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Background: The vegetable‐based diet alone does not provide the lysine (Lys) needed to maximize poultry productive performance. Objectives: This experiment aimed to evaluate the effects of dietary digestible Lys (dLys) level on productive and reproductive performance, egg quality, blood metabolites and immune responses in breeding Japanese quails (Coturnix japonica). Methods: The experiment was conducted in a completely randomized design with 6 treatments, 5 replicates and 15 (12 females and 3 meals) 10‐week‐old breeding Japanese quails each. A basal diet was formulated to meet nutritional requirements of breeding quails except dLys. The basal diet was supplemented with graded (+0.82 g/kg) levels of l‐Lys‐HCl, corresponding to dietary dLys levels of 0.690%, 0.755%, 0.820%, 0.885%, 0.950% and 1.015%. The experiment lasted for 12 weeks, which was divided into 3‐4‐week periods. Results: Significant differences were observed for egg production (EP), egg mass (EM) and feed efficiency (FE) in response to increasing dietary dLys concentration with quadratic trends. The highest traits were observed in the birds fed with a diet containing 0.885% dLys. However, feed intake, egg quality, reproductive performance, blood metabolites and immune responses against sheep red blood cell inoculation were not significantly affected by increasing dietary dLys concentrations. The dLys requirements during 11–14, 15–18, 19–22 and 11–22 (overall) weeks of age for optimal EP, EM and FE, based on the quadratic broken‐line regression analysis, were estimated 272, 265, 250 and 266; 293, 285, 264 and 279; and 303, 294, 281 and 293 mg/bird/day, respectively. Conclusions: The dLys requirements vary depending on the EP phase and the trait being optimized. The estimated dLys requirement for FE was higher than those for EP and EM. During the peak stage of the first laying cycle, the dietary dLys level of 0.932% and a daily intake of 303 mg dLys/bird are sufficient for optimal performance. [ABSTRACT FROM AUTHOR]

Abstract Background The vegetable‐based diet alone does not provide the lysine (Lys) needed to maximize poultry productive performance. Objectives This experiment aimed to evaluate the effects of dietary digestible Lys (dLys) level on productive and reproductive performance, egg quality, blood metabolites and immune responses in breeding Japanese quails (Coturnix japonica). Methods The experiment was conducted in a completely randomized design with 6 treatments, 5 replicates and 15 (12 females and 3 meals) 10‐week‐old breeding Japanese quails each. A basal diet was formulated to meet nutritional requirements of breeding quails except dLys. The basal diet was supplemented with graded (+0.82 g/kg) levels of l‐Lys‐HCl, corresponding to dietary dLys levels of 0.690%, 0.755%, 0.820%, 0.885%, 0.950% and 1.015%. The experiment lasted for 12 weeks, which was divided into 3‐4‐week periods. Results Significant differences were observed for egg production (EP), egg mass (EM) and feed efficiency (FE) in response to increasing dietary dLys concentration with quadratic trends. The highest traits were observed in the birds fed with a diet containing 0.885% dLys. However, feed intake, egg quality, reproductive performance, blood metabolites and immune responses against sheep red blood cell inoculation were not significantly affected by increasing dietary dLys concentrations. The dLys requirements during 11–14, 15–18, 19–22 and 11–22 (overall) weeks of age for optimal EP, EM and FE, based on the quadratic broken‐line regression analysis, were estimated 272, 265, 250 and 266; 293, 285, 264 and 279; and 303, 294, 281 and 293 mg/bird/day, respectively. Conclusions The dLys requirements vary depending on the EP phase and the trait being optimized. The estimated dLys requirement for FE was higher than those for EP and EM. During the peak stage of the first laying cycle, the dietary dLys level of 0.932% and a daily intake of 303 mg dLys/bird are sufficient for optimal performance.

Supplementing a diet with rumen-protected amino acids (AAs) is a common feeding strategy for efficient production. For a cost-effective use of rumen-protected AA, the accurate bioavailability of rumen-protected amino acids should be known and their metabolism after absorption needs to be well understood. The current study determined the bioavailability, absorption, utilization, and excretion of rumen-protected Lys (RP-Lys). Four ruminally cannulated cows in a 4 × 4 Latin square design (12 d for diet adaptation; 5 or 6 d for total collections) received the following treatments: L0, a basal diet; L25, the basal diet and L-Lys infused into the abomasum to provide 25.9 g/d L-Lys; L50, the basal diet and L-Lys infused into the abomasum to provide 51.8 g/d L-Lys; and RPL, the basal diet supplemented with 105 g/d (as-is) of RP-Lys to provide 26.7 g of digestible Lys. During the last 5 or 6 d in each period, 15N-Lys (0.38 g/d) was infused into the abomasum for all cows to label the pool of AA, and the total collection of milk, urine, and feces were conducted. 15N enrichment of samples on d 4 and 5 were used to calculate the bioavailability and Lys metabolism. We used a model containing a fast AA turnover (≤ 5 d) and slow AA turnover pool (> 5 d) to calculate fluxes of Lys. The Lys flux to the fast AA turnover pool (absorbed Lys + Lys from the slow AA turnover pool to fast AA turnover pool) was calculated using 15N enrichment of milk Lys. The flux of Lys from the fast AA turnover pool to milk and urine was calculated using 15N transfer into milk and urine. Then, absorbed Lys was estimated by the sum of Lys flux to milk and urine assuming no net utilization of Lys by body tissues. Duodenal Lys flow was estimated by 15N enrichment of fecal Lys. The bioavailability of RP-Lys was calculated from duodenal Lys flows and Lys absorption for RPL. Increasing Lys supply from L25 to L50 increased Lys utilization for milk by 9 g/d but also increased urinary excretion by 10 g/d. For RPL, absorbed Lys was estimated to be 136 g/d where 28 g of absorbed Lys originated from RP-Lys. In conclusion, 68% of bioavailability was obtained for RP-Lys. The Lys provided from RP-Lys was not only utilized for milk protein (48%) but also excreted in urine (20%) after oxidation.

Simple Summary: In recent years, affected by the international trade situation, China's corn import volume and import price have risen sharply, which has increased the production cost of poultry farming. Poultry nutritionists have been encouraged to use different grains instead of corn. However, it is unclear whether feeding broiler chickens with different starch sources affects the utilization of digestible lysine (dLys) in their body due to differences in digestion rate, thereby affecting broiler breast muscle protein and liver lipid metabolism. Therefore, this study aims at the above-mentioned problems. Here, we found that the waxy corn starch diet resulted in significantly higher expression levels of fat-synthesis-related genes than lipolysis-related genes, leading to abdominal fat deposition in broilers. Increasing the level of dLys in the diet increased the protein content in muscle by promoting protein synthesis and inhibiting protein degradation and also promoted the expression of lipolysis-related genes, thereby degrading the generation of abdominal fat in broilers. In conclusion, our findings signify that increasing the dLys level to 1.32% when using the waxy corn starch diet could improve carcass traits. This study investigated the effects of digestible lysine (dLys) in different dietary starch sources on liver lipid metabolism and breast muscle protein metabolism in broiler chickens. The experimental design was a 3 × 3 two-factor completely randomized design. A total of 702 one-day-old male Arbor Acres Plus broilers were randomly divided into nine treatments of six replicate cages with thirteen birds each. The treatments consisted of three different starch sources (corn, cassava and waxy corn) with three different dLys levels (1.08%, 1.20% and 1.32%). The trial lasted from 1 to 21 days. Carcass traits, serum metabolites, breast muscle protein and liver lipid metabolism were evaluated. A significant interaction effect (p < 0.05) for dietary starch sources and dLys levels was noted in the percentage of abdominal fat and gene expression related to breast muscle protein metabolism throughout the experimental period. The waxy corn starch diet and a 1.08% dLys level in the diet increased both the percentage of abdominal fat (p < 0.01) and blood total cholesterol (p < 0.05) in the broilers. The waxy corn starch diet significantly upregulated the mRNA expressions of Eif4E, AMPK, FABP1, ACC and CPT1 (p < 0.05). The 1.32% dLys level significantly upregulated the mRNA expressions of mTOR, S6K1, Eif4E, AMPK and PPARα (p < 0.05) and significantly downregulated the mRNA expressions of MuRF and Atrogin-1 (p < 0.05). In summary, the waxy corn starch diet resulted in significantly higher expression levels of fat-synthesis-related genes than lipolysis-related genes, leading to abdominal fat deposition in broilers. Increasing the level of dLys in the diet increased the protein content in muscle by promoting protein synthesis and inhibiting protein degradation and also promoted the expression of lipolysis-related genes, thereby degrading the generation of abdominal fat in broilers. Our findings signify that increasing the dLys level to 1.32% when using the waxy corn starch diet could improve carcass traits. [ABSTRACT FROM AUTHOR]

SUMMARY: The current objective was to expand on previous research using the Cobb MV × Cobb 500 to determine its finisher digestible Lys (dLys) requirement (Req; d 28–41), as well as the effect of feeding varying finisher dLys levels on performance, processing, and economics. This was a 2 Sex (male or female) × 8 dLys factorial arrangement, wherein the experimental diets consisted of a practical control; (PRAC-CON; 0.94% dLys) and 7 other diets with varying dLys concentrations (0.72%, 0.80%, 0.88%, 0.94%, 1.02%, 1.10%, and 1.18%) Chicks were fed common starter (1.28% dLys) and grower diets (grower 1 and 2 dLys were 1.18 and 1.08%, respectively). In general, males had improved performance versus females while females had increased processing yield (% of live weight) vs. males. Also, increasing finisher dLys resulted in improvements in performance and processing metrics, regardless of sex. Quadratic regression (QR; 95% of vertex) and linear and quadratic broken line (LBL; QBL) models were utilized to estimate dLys Req for each sex. The estimated dLys Req range for females was 0.752-1.292% and males, 0.748 to 1.320%, when using all models. An economic model determined 1.10% finisher dLys to be most profitable. These data demonstrate that increasing finisher dLys can improve Cobb MV × Cobb 500 performance and processing; however, the optimal dLys Req can vary depending on sex, regression model, response parameter, and economics.

The influence of the energy and the standardized ileal digestible lysine (DLys) content of the diet on egg production and egg quality, was studied in brown-egg laying hens from 18 to 41 wk of age. The experimental design was completely randomized with 10 treatments organized as a 2 × 5 factorial with 2 energy concentrations (2,750 and 2,800 kcal AMEn/kg) and 5 levels of DLys (values varied from 0.66 to 0.78% and 0.67 to 0.79%, for the low and high energy diets, respectively). Each treatment was replicated 10 times (10 hens per replicate). The data were analyzed using the MIXED procedure of SAS with energy concentration and DLys content of the diets as main effects. In addition, the effects of the DLys on the variables studied were partitioned into its lineal and quadratic components. From 18 to 21 wk of age (pre-peak phase), diet composition had limited effects on egg production. From 22 to 41 wk of age (peak phase), however, an increase of 50 kcal AMEn/kg diet increased egg weight (P < 0.05) and tended to improve energy intake (P = 0.083) and feed conversion ratio (P = 0.074). An increase in DLys improved linearly (P < 0.001) egg production, egg weight, egg mass, feed conversion, and energy conversion ratio, and tended to increase BW gain (P = 0.074). Diet composition did not any affect egg quality trait except shell strength that increased linearly (P < 0.05) with increases in the DLys. Cumulatively (18–41 wk of age), egg weight increased (P < 0.05) as the energy and the DLys content of the diet increased. In summary, an increase in energy and DLys content of the diet had limited effects on egg production during the prepeak phase but improved egg production, feed conversion ratio, and BW gain during the peak phase. The data indicate that hens require at least 839 mg DLys/d to maximize egg production in the peak production phase.

This study investigated the effects of digestible lysine (dLys) in different dietary starch sources on liver lipid metabolism and breast muscle protein metabolism in broiler chickens. The experimental design was a 3 × 3 two-factor completely randomized design. A total of 702 one-day-old male Arbor Acres Plus broilers were randomly divided into nine treatments of six replicate cages with thirteen birds each. The treatments consisted of three different starch sources (corn, cassava and waxy corn) with three different dLys levels (1.08%, 1.20% and 1.32%). The trial lasted from 1 to 21 days. Carcass traits, serum metabolites, breast muscle protein and liver lipid metabolism were evaluated. A significant interaction effect (p < 0.05) for dietary starch sources and dLys levels was noted in the percentage of abdominal fat and gene expression related to breast muscle protein metabolism throughout the experimental period. The waxy corn starch diet and a 1.08% dLys level in the diet increased both the percentage of abdominal fat (p < 0.01) and blood total cholesterol (p < 0.05) in the broilers. The waxy corn starch diet significantly upregulated the mRNA expressions of Eif4E, AMPK, FABP1, ACC and CPT1 (p < 0.05). The 1.32% dLys level significantly upregulated the mRNA expressions of mTOR, S6K1, Eif4E, AMPK and PPARα (p < 0.05) and significantly downregulated the mRNA expressions of MuRF and Atrogin-1 (p < 0.05). In summary, the waxy corn starch diet resulted in significantly higher expression levels of fat-synthesis-related genes than lipolysis-related genes, leading to abdominal fat deposition in broilers. Increasing the level of dLys in the diet increased the protein content in muscle by promoting protein synthesis and inhibiting protein degradation and also promoted the expression of lipolysis-related genes, thereby degrading the generation of abdominal fat in broilers. Our findings signify that increasing the dLys level to 1.32% when using the waxy corn starch diet could improve carcass traits.

Broiler chickens grow rapidly, and their nutrient requirements change daily. However, broilers are fed three to five diet phases, meaning nutrients are under or over-supplied throughout production. Increasing diet phases improves production efficiency as there is less time in the production cycle that nutrients are in under or over-supply. Nevertheless, the process of administering four or more diets is costly and often impractical. New technologies are now available to blend feed to match the daily nutrient requirements of broilers. Thus, the aim of this review is to evaluate previous studies measuring the impact of increasing feed phases on nutrient utilisation and growth performance, and review recent studies taking this concept to the extreme; precision nutrition - feeding a new diet for each day of the production cycle. This review will also discuss how modern precision feeding technologies have been utilised and the potential that new technologies may bring to the poultry industry. The development of a precision nutrition regime which targets daily requirements by blending dietary components on farm is anticipated to improve the efficiency of production, reduce production cost and therefore improve sustainability of the industry. There is also potential for precision feeding technology along with precision nutrition strategies to deliver a plethora of other management and economic benefits. These include increased fluidity to cope with sudden environmental or market changes, and the ability to alter diets on a farm by farm level in a large, integrated operation. Thus, the future possibilities and practical implications for such technologies to generate a paradigm shift in feed formulation within the poultry industry to meet the rising demand for animal protein is also discussed.

• There is a need to better understand amino acid metabolism. • We determined the bioavailability and examined the metabolism of rumen-protected Lysine. • An increase in digestible Lysine increased Lysine oxidation and excretion in urine. • Lysine from rumen-protected Lysine was utilized for milk but also excreted in urine. • The limitations of the experiment are the high cost and labor intensive. Supplementing a diet with rumen-protected amino acids (AAs) is a common feeding strategy for efficient production. For a cost-effective use of rumen-protected AA, the accurate bioavailability of rumen-protected amino acids should be known and their metabolism after absorption needs to be well understood. The current study determined the bioavailability, absorption, utilization, and excretion of rumen-protected Lys (RP-Lys). Four ruminally cannulated cows in a 4 × 4 Latin square design (12 d for diet adaptation; 5 or 6 d for total collections) received the following treatments: L0 , a basal diet; L25 , the basal diet and L-Lys infused into the abomasum to provide 25.9 g/d L-Lys; L50 , the basal diet and L-Lys infused into the abomasum to provide 51.8 g/d L-Lys; and RPL , the basal diet supplemented with 105 g/d (as-is) of RP-Lys to provide 26.7 g of digestible Lys. During the last 5 or 6 d in each period, 15N-Lys (0.38 g/d) was infused into the abomasum for all cows to label the pool of AA, and the total collection of milk, urine, and feces were conducted. 15N enrichment of samples on d 4 and 5 were used to calculate the bioavailability and Lys metabolism. We used a model containing a fast AA turnover (≤ 5 d) and slow AA turnover pool (> 5 d) to calculate fluxes of Lys. The Lys flux to the fast AA turnover pool (absorbed Lys + Lys from the slow AA turnover pool to fast AA turnover pool) was calculated using 15N enrichment of milk Lys. The flux of Lys from the fast AA turnover pool to milk and urine was calculated using 15N transfer into milk and urine. Then, absorbed Lys was estimated by the sum of Lys flux to milk and urine assuming no net utilization of Lys by body tissues. Duodenal Lys flow was estimated by 15N enrichment of fecal Lys. The bioavailability of RP-Lys was calculated from duodenal Lys flows and Lys absorption for RPL. Increasing Lys supply from L25 to L50 increased Lys utilization for milk by 9 g/d but also increased urinary excretion by 10 g/d. For RPL, absorbed Lys was estimated to be 136 g/d where 28 g of absorbed Lys originated from RP-Lys. In conclusion, 68% of bioavailability was obtained for RP-Lys. The Lys provided from RP-Lys was not only utilized for milk protein (48%) but also excreted in urine (20%) after oxidation. [ABSTRACT FROM AUTHOR]

Broiler chickens grow rapidly, and their nutrient requirements change daily. However, broilers are fed three to five diet phases, meaning nutrients are under or oversupplied throughout production. Increasing diet phases improves production efficiency as there is less time in the production cycle that nutrients are in under or over-supply. Nevertheless, the process of administering four or more diets is costly and often impractical. New technologies are now available to blend feed to match the daily nutrient requirements of broilers. Thus, the aim of this review is to evaluate previous studies measuring the impact of increasing feed phases on nutrient utilisation and growth performance, and review recent studies taking this concept to the extreme; precision nutrition - feeding a new diet for each day of the production cycle. This review will also discuss how modern precision feeding technologies have been utilised and the potential that new technologies may bring to the poultry industry. The development of a precision nutrition regime which targets daily requirements by blending dietary components on farm is anticipated to improve the efficiency of production, reduce production cost and therefore improve sustainability of the industry. There is also potential for precision feeding technology along with precision nutrition strategies to deliver a plethora of other management and economic benefits. These include increased fluidity to cope with sudden environmental or market changes, and the ability to alter diets on a farm by farm level in a large, integrated operation. Thus, the future possibilities and practical implications for such technologies to generate a paradigm shift in feed formulation within the poultry industry to meet the rising demand for animal protein is also discussed. [ABSTRACT FROM AUTHOR]

Abstract A 12-week feeding experiment was conducted to determine the lysine requirement for Totoaba macdonaldi juveniles. Five isonitrogenous and isocaloric diets, with 420 g kg−1 crude protein and 21 MJ kg−1, were formulated and produced to contain increasing levels of dietary lysine. After HPLC analysis the actual lysine dietary levels were found to be 16, 17.7, 22, 25.1, and 27.8 g kg−1 of diet dry matter. Each diet was randomly assigned to triplicate groups of 10 fish and fed to apparent satiation by hand, three times a day. Growth in terms of weight and length, survival and feed utilization (as feed conversion rate, protein efficiency ratio, and protein productive value) were used as response variables. Lysine digestibility of diets was estimated using acid-insoluble ash as an internal marker. Results revealed that final weight and weight gain significantly increased with increasing levels of lysine in the diet, from 16 up to 17.7 g kg−1 of the dry matter (DM). Thermal growth coefficient was the response variable used to estimate the lysine requirement using a quadratic broken-line model (R2 = 0.82). The model estimated that highest growth is obtained with a dietary lysine level of 19.3 ± 0.8 g kg−1 DM or 46 g kg−1 of dietary crude protein (equivalent to 16.4 g kg−1 of digestible lysine). Using the results here obtained, estimates of other amino acid requirements were calculated using the quantified lysine requirement and totoaba whole-body amino acid concentrations, which can serve as a base-line to formulate practical diets for juvenile totoaba, summing for the further development of the commercial culture of this promising species. Highlights • First report of Totoaba macdonaldi lysine requirement and to estimate other EAA requirements based on whole-body EAA relative concentrations. • Dietary lysine requirement for juvenile Totoaba was determined to be 19.3 ± 0.8 g kg−1 of the DM or 46 g kg−1 of the crude protein in the diet. • Based on the analyzed digestibility of lysine, this value corresponds to a digestible lysine requirement of 16.4 g kg−1 of the DM [ABSTRACT FROM AUTHOR]

ABSTRACTThe digestible lysine requirement for the growth performance of broilers fed diets with decreasing energy to protein ratio and reared under subtropical summer conditions were determined. Treatments consisted of five wheat-based diets with five levels (0.90, 0.95, 1.00, 1.05 and 1.10%) of digestible lysine (DL) and lowering energy to protein ratio (EPR; 13.6, 12.8, 12.0, 11.4 and 11.0), with five replicates of 80 birds each (n = 2000). Body weight gain (BWG) significantly increased by increasing DL levels during wk 1 (p

Quantitative control of nutrient intake may decrease the incidence of wooden breast (WB) and white striping (WS) myopathies with some impairment of live performance. Two experiments (Exp) utilizing Yield Plus × Ross 708 male broilers were conducted to determine if a reduction in myopathies may be obtained through a qualitative approach by reducing digestible lysine (dLys) density. All birds received an identical starter diet until 11 d of age. In Exp 1 (63 pens; 22 birds/pen), each pen was then randomly assigned to 1 of the following 7 dietary treatments (TRT) for a 47 d production period. Seven dietary treatments were provided for the grower 1 (G1; 12 to 18 d of age) and grower 2 (G2; 19 to 26 d of age) phases: 1) 100% of primary breeder recommendations for dLys throughout Exp; 2) 85% of TRT 1 dLys for G1; 3) 85% of TRT 1 dLys for G2; 4) 85% of TRT 1 dLys for G1 and G2; 5) 75% of TRT 1 dLys for G1; 6) 75% of TRT 1 dLys for G2; 7) 75% of TRT 1 for G1 and G2. In Exp 2 (24 pens; 30 birds/pen), birds were randomly assigned to 1 of the following 4 dietary TRT (Table 2) during a 61 d production period. Four dietary treatments were provided for the grower (G; 12 to 28 d) and finisher 1 (F1; 29 to 40 d of age) phases: 1) 100% of primary breeder recommendations for dLys 2) 85% of TRT 1 dLys for G; 3) 85% of TRT 1 dLys for F1; 4) 85% of TRT 1 dLys for G and F1; thereafter, birds received common finisher 1 (Exp 1: 27 to 42 d of age), finisher 2 (Exp 2: 41 to 48 d of age) and withdrawal (Exp 1: 43 to 47 d of age; Exp 2: 49 to 61 d of age) diets. Ideal amino acid ratios were not maintained in reduced dLys diets in either Exp. At 48 (Exp 1; 18 birds/pen) and 62 (Exp 2; 30 birds/pen) d of age, selected birds were processed and fillets were visually scored for WB and WS. No differences (P > 0.05) in cumulative live performance responses between TRT 1 and the remaining TRT were observed in either Exp. In Exp 1, the incidence of severe WB (20.8%) and WS (42.3%) at 48 d of age among birds receiving TRT 7 was reduced (P < 0.01) compared with TRT 1 (WB: 36.6%; WS: 64.3%), at the expense of reduced (P = 0.003) breast weights and yield. In Exp 2, the incidence of severe WB (18.8%) and WS (17.8%) at 62 d of age for birds receiving TRT 4 was reduced (P < 0.05) compared with TRT 1 (WB: 39.3%; WS: 38.3%), without any detrimental effects on processing characteristics. These results indicate that altering dietary dLys during critical periods of the growth trajectory may be a viable strategy for reducing the incidence and severity of WB and WS. [ABSTRACT FROM AUTHOR]

Exogenous phytase could influence dietary protein availability by variation in using dose. The objective of the present study was to determine if incremental dosing of an evolved E.coli 6-phytase would lead to improvements in lysine availability through evaluating performance and bone status in Bovans White layers. A total of 182 layers were placed in individual cages and distributed to 13 treatments: a 3 × 4 factorial arrangement with three levels of digestible lysine (dLys - 0.67, 0.77, and 0.87 %) and four doses of phytase (0, 300, 1 200, and 4 800 FTU/kg) in 0.12 % available P (avP) diets. Additionally, one phytase-free control treatment was included with 0.25 % avP and 0.87 % dLys. Productive parameters were recorded for 25 weeks, from 39 week-old. At the end, abdominal fat deposition and the tibia were sampled; in bone was determined breaking strength and bone ash. Layers fed 1 200 FTU/kg phytase increased egg production percentage (F3,169 = 2.01, p = 0.111), abdominal fat deposition (F3,169 = 2.52, p = 0.059), bone breaking strength (F3,169 = 4.29, p = 0.006) and bone ash weight (F3,169 = 3.62, p = 0.014) compared with non-phytase inclusion. Furthermore, 1 200 FTU/kg phytase decreased incidence of broken eggs and soft-shell eggs (F3,169 = 2.9, p = 0.036). Phytase and dLys levels influenced egg mass and bone ash concentration (F12,169 = 1.86, p = 0.043). FCR and body weight loss was reduced with phytase inclusion (respectively: F12,169 = 2.43, p = 0.006, and F12,169 = 2.24, p = 0.012). Phytase-free control diet increased egg weight (F12,169 = 3.70, p < 0.001), but gave greater BW loss (F12,169 = 17.79, p < 0.001), less abdominal fat content (F12,169 = 5.85, p < 0.001), and no effect on other variables (p > 0.07). In conclusion, 1 200 FTU/kg of phytase improved productive performance and preserved body weight and bone status, without equivalence of phytase inclusion for dLys level, even with higher doses. [ABSTRACT FROM AUTHOR]

Modern broilers have been submitted to continuous genetic improvement, and therefore, their nutritional requirements must be constantly updated to ensure their performance. Two experiments were carried out to evaluate different digestible lysine levels for starter (1021 days) and grower (22-35 days) phases. The experiments were carried out with male and female Cobb 500 broilers, distributed according to a randomized block experimental design in a 5x2 factorial arrangement (5 increasing digestible lysine levels x 2 sexes), totaling 10 treatments, with 8 replicates of 22 and 20 birds during the starter and grower phase, respectively. Digestible lysine levels of 1.06, 1.12, 1.18, 1.24, and 1.30 were used in the starter diets (10-21 days) and 0.9, 0.98, 1.04, 1.10, and 1.16% in the grower diets (22-35 days). Based on the statistical analyses of the evaluated performance parameters, digestible lysine requirements for maximum performance were determined as 1.22% for males and 1.24% for females in the starter phase, and 1.16% for both sexes in the grower phase. Carcass and performance results indicate that digestible lysine requirements vary with sex and evaluated production parameter. Considering the most relevant broiler production parameters, in 22- to 35-d-old males, digestible lysine requirement for breast meat yield (1.16%) was higher than those for feed conversion ratio (1.07%) and weight gain (1.05%).

The aim of the current study was to determine the digestible lysine (DLys) requirement of Cherry Valley ducks from 1 to 14 d and from 15 to 35 d of age. One-day-old male Cherry Valley ducks (n = 320) were divided randomly and evenly into five treatments with 8 replicates of 8 birds. Ducks were fed adequate levels of digestible amino acid but with graded levels of DLys: 0.80, 0.88, 0.96, 1.04, and 1.12% from 1 to 14 d; 0.60, 0.68, 0.76, 0.84, and 0.92% from 15 to 35 d. At 35 d of age, 8 ducks per treatment were slaughtered for evaluating the yields of abdominal fat, subcutaneous fat, breast meat, and leg meat. Additionally, a 7-d metabolizable experiment was conducted with ducks of the same hatch beginning on d 35 (8 ducks per treatment). The results showed that the DLys level in diet had a quadratic relationship both with the average daily gain (ADG) and feed:gain ratio (F/G). According to the quadratic model, an optimum digestible lysine level was 0.948% from 0 to 14 d and 0.758% from 15 to 35 d based on ADG. The digestible lysine level for obtaining minimum F/G were 0.986% (0 ~ 14 d) and 0.792% (15 ~ 35 d), respectively. Breast meat yield (P = 0.110) and subcutaneous fat percentage (P = 0.021) showed a quadratic or linear response to the increasing dietary DLys level. To achieve maximum breast meat yield, the digestible lysine level of 0.961% and 0.761% were needed for the starter period (1 ~ 14 d) and the growth period (14 ~ 35 d), respectively. N excretion showed a quadratic response to the increasing dietary DLys level (P = 0.103). The results of the current study suggested that the optimum digestible lysine level was very different with the response criterion. The dietary digestible lysine levels were 0.948, 0.961% in the starter period (1 ~ 14 d) and 0.758, 0.761% in the growth period (15 ~ 35 d) for ADG, F/G, respectively. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate the prevalence and severity of white striping (WS) and wooden breast (WB) in breast fillets from broilers fed diets with increasing digestible Lysine (dLys) from 12 to 28 d (Exp. 1) and from 28 to 42 d (Exp. 2). Trials were sequentially conducted using one-d-old male, slow-feathering Cobb 500 × Cobb broilers, both with 6 treatments and 8 replicates. Increasing dLys levels were equally spaced from 0.77 to 1.17% in Exp. 1 and from 0.68 to 1.07% in Exp. 2. The lowest dLys diet was not supplemented with L-Lysine (L-Lys) in either one of the studies and all other essential amino acid (AA) met or exceeded current commercial recommendations such that their dietary concentrations did not limit broiler growth. Four birds per pen were randomly selected from each replication and processed at 35 and 42 d in Exp. 1 and Exp. 2, respectively. Deboned breast fillets (Pectoralis major) were submitted to a 3 subject panel evaluation to detect the presence of WS and WB, as well as to provide scores of WS (0-normal, 1-moderate, 2-severe) and WB (0-normal, 1-moderate light, 2-moderate, 3-severe). Increasing the level of dLys had a positive effect on BW, carcass, and breast weight, as well as breast yield. White striping and WB prevalences were 32.3 and 85.9% in Exp. 1 and 87.1 and 89.2% in Exp. 2. Birds fed diets not supplemented with L-Lys had the lowest average WS and WB scores (0.22 and 0.78 in Exp. 1 and 0.61 and 0.68 in Exp. 2). White striping and WB presented linear responses to performance variables in Exp. 1, whereas quadratic responses were observed for all variables in Exp. 2. In conclusion, increasing the level of dLys improved growth performance and carcass traits as well as induced the occurrence and severity of WS and WB lesions. [ABSTRACT FROM AUTHOR]

One thousand eight hundred and ninety male broilers of two strain crosses (fast and slow initial growth) were fed different ideal protein profiles in four-phase feed programs: 1 to 7, 8 to 21, 22 to 34 and 35 to 40 days of age. All vegetable, corn-soybean meal feeds were formulated to maintain the Met+Cys:Lys and Thr:Lys relationships at 75 and 65%, respectively, on true digestible basis. Three ideal protein profiles were used: low, medium and high. From 1 to 21 days of age, half of the birds fed low and high diets were changed to high and low diets, respectively. Birds on the medium diet were kept on the same diet until the end of the study. A 3 × 2 (ideal protein profile x strain cross) factorial design was used for the period from 1 to 21 days and a 5 × 2 design thereafter. Carcass and commercial cuts were performed at 34 and 40 days of age to determine corresponding live weight and carcass yields. In general, the fast strain growth was superior in comparison to the low one when live performance and carcass and commercial cuts were evaluated. Live performance was positively affected by the increases in the dietary protein profiles; however, processing yield parameters could not be related with the dietary parameters. The low diets, which have similar protein contents to those used in some integrations, were shown to produce poor responses and, therefore are not recommended for broilers from 1 to 40 days of age. Alternating low and high ideal protein profiles at 21 days could result in similar feed conversions, and therefore, can lead to production cost reduction.Mil oitocentos e noventa frangos de corte machos de duas linhagens comerciais (de crescimento inicial rápido e lento) receberam dietas com diferentes perfis de proteína ideal em programas alimentares de quatro fases: 1 a 7; 8 a 21; 22 a 34; e 35 a 40 dias de idade. Dietas exclusivamente vegetais, à base de milho e farelo de soja, foram formuladas de modo a manter as relações Met+Cis:Lis e Ter:Lis em 75 e 65%, respectivamente, em base digestível verdadeira. Foram utilizados três perfis de proteína ideal: baixo, médio e alto. Aos 21 dias de idade, metade das aves consumindo dieta de perfil baixo passou a receber perfil alto e metade daquelas que receberam perfil alto passaram a receber dieta de perfil baixo. As aves que recebiam dieta de perfil médio permaneceram sem alteração até o final do estudo. Utilizou-se esquema fatorial 3 × 2 (perfil de proteína ideal × linhagem) para o período de 1 a 21 dias e 5 × 2 para o período de 21 a 40 dias de idade. Além das respostas de desempenho zootécnico, foram realizados abates aos 34 e 40 dias de idade para determinação dos rendimentos de carcaça e de cortes. De modo geral, a linhagem de crescimento rápido foi superior à de crescimento lento para as respostas de crescimento e rendimentos de carcaça e cortes. As aves responderam significativamente ao aumento no conteúdo proteico das rações, independentemente da linhagem utilizada para características de desempenho zootécnico; entretanto, as respostas de rendimento pós-abate não puderam ser relacionadas da mesma forma. A alternância de perfis proteicos aos 21 dias pode levar a conversões alimentares similares e, portanto, reduzir o custo de produção.

O objetivo neste estudo foi avaliar diferentes modelos ajustados às respostas de ganho de peso obtidas em experimento com aves da linhagem ISA Label no período de 1 a 28 dias de idade. Foram utilizados 480 pintos de ambos os sexos, distribuídos em delineamento inteiramente casualizado, em arranjo fatorial 4 X 2 (níveis de lisina X sexo), com três repetições, com 20 aves por unidade experimental. Uma ração basal foi formulada para atender às exigências das aves, exceto em lisina. Essa ração foi suplementada com L-lisina HCl em substituição ao ácido L-glutâmico, resultando em rações experimentais isonitrogênicas e isoenergéticas contendo 0,85; 0,97; 1,09 e 1,21% de lisina digestível. As respostas de ganho de peso foram ajustadas de acordo com os níveis de lisina da ração pelos modelos Linear Reponse Plateau (LRP), segmentado de duas inclinações, polinomial quadrático e exponencial. A primeira intersecção da equação quadrática com o platô do LRP também foi utilizado para estimar o nível ótimo. Os níveis de lisina digestível estimados pelos modelos LRP, segmentado e quadrático, foram 0,999; 1,010 e 1,116%, respectivamente. Na combinação do modelo quadrático com o LRP, a estimativa da exigência de lisina digestível foi de 1,041%. O modelo exponencial proporcionou estimativa de 1,066%, considerando 95% da resposta assintótica. Com base nos custos com alimentação, esse mesmo modelo gerou estimativas de 1,000 e 1,030% quando o custo do quilograma de L-lisina HCl foi R$ 8,50 e R$ 6,50, respectivamente. Considerando as limitações de cada um dos modelos propostos, o procedimento para estimar as exigências de lisina digestível pela primeira intersecção da equação quadrática com o platô do LRP foi o mais adequado para melhorar o ganho de peso das aves quando variáveis econômicas não foram consideradas.The objective of this study was to evaluate different models in the adjustment of weight gain (WG) responses, obtained in an experiment carried out with ISA Label birds from 1 to 28 days of age. A total of 480 male and female chicks were distributed in a completely randomized design, in a 4 X 2 factorial arrangement (lysine levels X sex), with three replications of 20 birds each. The basal diet was formulated to meet the chick requirements, except for lysine. This diet was supplemented with L-lysine HCl replacing the L-glutamic acid and resulting in experimental diets containing 0.85, 0.97, 1.09 and 1.21% digestible lysine. The weight gain response was adjusted to lysine levels according to following models: Linear Response Plateau (LRP), segmented regression with two slopes, quadratic and exponential. The first interception of the quadratic model on the LRP plateau was used to estimate the optimum lysine level. The lysine levels estimated according to LRP, segmented regression and quadratic models were 0.999, 1.010 and 1.116%, respectively. The digestible lysine level estimated by the combination of quadratic with LRP models was 1.041%. The exponential model provided an estimate of digestible lysine digestible of 1.066%, considering 95% of the asymptotic response. Based on the economic approach this model generated estimates of 1.000 and 1.030%, when the L-lysine cost was R$ 8.50 and R$ 6.50, respectively. Considering the limitations of each one of the proposed models, procedure to estimate the digestible lysine by the interception of quadratic equation with LRP plateau was the most adequate to optmize the weight gain of the birds when economic variables were not considered.

The objective of the present study was to investigate crude protein reduction and the methionine+cystine and threonine to lysine ratios in diets for reversed Nile tilapia fingerlings (Oreochromis niloticus), Thai strain. Four hundred and twenty Nile tilapia fingerlings with an average initial weight of 1.83 ± 0.02 g were placed in a completely randomized design, with five treatments, seven replications per treatment and 12 fish per experimental unit, for 37-days. Two crude protein (CP) levels were evaluated (32 and 28%). The diet with 32% CP had methionine+cystine:lysine and threonine:lysine ratios of 63 and 74%, respectively. Three diets with 28% CP had methionine+cystine:lysine and threonine:lysine ratios of 63 and 74%, 60 and 74% and 60 and 69%, respectively. The diet with 28% CP and had methionine+cystine:lysine ratio of 63% and threonine:lysine of 74% and was supplemented with 0.3% glutamic acid. The fish were kept in thirty-five 130 L aquariums supplied with single-pass flow-through water, individual aeration and fed ad libitum six times per day. Fish fed the diet with 32% CP had lower protein efficiency ratios and nitrogen efficiency ratios. The diet CP level was 28% and the methionine+cystine and threonine to lysine ratios were 60 and 69%, respectively.Objetivou-se avaliar a redução do nível de proteína bruta e as relações dos aminoácidos metionina+cistina e treonina digestíveis com a lisina digestível em dietas para alevinos revertidos de tilápia-do-nilo (Oreochromis niloticus), da linhagem tailandesa. Um experimento com duração de 37 dias foi realizado utilizando-se 420 alevinos com peso inicial de 1,83 ± 0,02 g, distribuídos em delineamento inteiramente ao acaso, composto de 5 dietas, 7 repetições e 12 peixes por unidade experimental. Foram avaliados dois níveis de PB (32 e 28%) em diversas dietas experimentais. Na dieta com 32% de PB, foram mantidas as relações de metionina+cistina e treonina com lisina de 63 e 74%, respectivamente; nas três dietas com 28% de PB, as relações de metionina+cistina e treonina com lisina foram de 63 e 74%, 60 e 74% e 60 e 69%, respectivamente; e, na dieta com 28% de PB, as relações de metionina+cistina e treonina com lisina foram de 63 e 74%, respectivamente, porém com acréscimo de 0,3% de ácido glutâmico. Os peixes foram mantidos em 35 aquários de 130 litros, com abastecimento de água, aeração individual e alimentação à vontade em seis refeições diárias. Os peixes mantidos com a dieta com 32% de PB apresentaram menores eficiências de retenção de proteína e de nitrogênio. O nível de PB de rações para alevinos de tilápia-do-nilo deve ser de 28,0% e as relações de metionina+cistina digestível e treonina digestível com a lisina, de 60 e 69%, respectivamente.

Objetivou-se avaliar o efeito da redução da proteína bruta (PB) da ração com suplementação de aminoácidos, com base no conceito de proteína ideal, sobre o desempenho de alevinos de tilápia-do-nilo (Oreochromis niloticus). Utilizaram-se 396 alevinos, linhagem tailandesa, com 0,80 ± 0,17 g de peso vivo, distribuídos em delineamento de blocos ao acaso, composto de seis tratamentos (32, 31, 30, 29, 28 e 27% de PB), seis blocos por tratamento e 11 peixes por unidade experimental. As rações foram formuladas para serem isoenergéticas e isolisínicas digestíveis, mantendo-se constantes as relações mínimas dos aminoácidos com a lisina. Os peixes foram mantidos em 36 aquários de 130 L, dotados de abastecimento de água, temperatura controlada e aeração individual, e alimentados à vontade seis vezes ao dia durante 40 dias. A redução do teor de proteína bruta da ração não afetou o ganho de peso, a taxa de crescimento específico, o consumo de ração, o consumo de lisina digestível, o teor de proteína corporal, as taxas de deposição de gordura e de proteína e a eficiência de retenção de nitrogênio dos peixes. Os peixes alimentados com rações com 27% de PB apresentaram pior conversão alimentar, menor eficiência de utilização da lisina para ganho, menor consumo de nitrogênio e umidade corporal, maior eficiência protéica para ganho e mais alto teor de gordura corporal. O nível de proteína bruta da ração para alevinos de tilápia-do-nilo pode ser reduzido em quatro pontos percentuais (de 32 para 28%), pois essa redução não prejudica o desempenho dos animais, desde que as rações sejam suplementadas com aminoácidos essenciais limitantes.The effect of decreasing dietary crude protein (CP) with supplementation of amino acids, based on the ideal protein concept on Nile tilapia (Oreochromis niloticus) fingerlings performance was evaluated. A total of 396 fingerlings from Thai strain, with 0.80 ± 0.17 g of BW, was allotted to a randomized block design, with six levels of CP (32, 31, 30, 29, 28 and 27% of CP) in the diets, six replications with 11 fish each. The diets were formulated to be isocaloric and digestible isolysine, remaining constant the amino acids to lysine minimum ratio. The fish were kept in 36 aquariums of 130 L, equipped with water supply, controlled temperature and individual aeration, and ad libitum fed six times a day for 40 days. The reduction of CP content of the diet did not affect weight gain, specific growth rate, feed intake, digestible lysine intake, body protein content, fat and protein deposition rates and nitrogen retention efficiency of fishes. The fish fed diets with 27% of CP lower feed: gain ratio, lysine efficiency for gain, nitrogen intake and body water and higher protein efficiency for gain and body fat content. The level of crude protein of the diet for Nile tilapia fingerlings can be reduced by four percentage points (from 32 to 28%), without negative effect on the performance of the animals, since the diets are supplemented with essential limiting amino acids.

Avaliaram-se quatro níveis de proteína bruta (PB) em dietas consideradas comerciais fornecidas a suínos machos castrados nas fases de crescimento e terminação. Foram utilizados 48 machos castrados de mesma linhagem genética, com pesos iniciais de 30,8 ± 0,12 kg (fase de crescimento) e 61,2 ± 0,89 kg (fase de terminação), segregados no sistema de produção. Os animais foram distribuídos em delineamento experimental de blocos ao acaso, compostos de quatro tratamentos (níveis de PB) e seis repetições e dois animais por unidade experimental. Os níveis de PB testados foram 19,5; 18,0; 16,5 e 15,0% na fase crescimento e 18,0; 16,5; 15,0 e 13,5% na fase terminação. Na fase crescimento, não foram constatadas diferenças no desempenho dos machos castrados. Independentemente do nível de PB na dieta, as exigências nutricionais foram atendidas, não obstante, a dieta com 16,5% PB indicou maior viabilidade econômica, calculada como margem bruta decorrente da alimentação. Semelhante à fase de crescimento, na fase de terminação os níveis de PB da dieta não promoveram diferenças no desempenho e nas características de carcaça dos animais ao abate. Ao considerar a margem bruta atribuída à alimentação, a dieta com 15,0% PB permitiria maior retorno econômico no período correspondente ao intervalo dos 60 aos 100 kg. A variação da proteína dietética com a suplementação dos principais aminoácidos não prejudicou o desempenho de suínos machos castrados nas fases de crescimento e terminação criados em condições desejáveis de saúde, segregados, em sistema de criação comercial. Pequenas variações entre aminoácidos não prejudicam o desempenho de suínos machos castrados nas fases de crescimento e terminação, desde que as exigências de lisina digestível e dos demais aminoácidos limitantes sejam mantidas próximas às relações mínimas atualmente indicadas.It was evaluated four crude protein (CP) levels in diets considered as commercial fed to barrows in the growing and finishing phases. A total of 48 barrows, from the same genetic strain, averaging initial weights of 30.8 ± 0.12 kg (growing phase) and 61.2 ± -0.89 kg (finishing phase), segregated in the production system, was used. The animals were allotted to randomized blocks design, composed of four treatment (level of CP) and six replications and two animals per experimental unit. The CP levels tested were: 19.5, 18.0, 16.5, and 15.0% in growing and 18.0, 16.5, 15.0 and 13.5% in finishing phases. There was no difference in the growing phase of barrows performance. Independently of the dietary CP levels, the nutritional requirements were supplied, in spite of the diet with 16.5% CP indicated greater economic viability, calculated as gross margin due to the feed. Similar to the growing phase, there were no differences among CP levels on performance and carcass characteristics of finishing barrows at slaughter. The gross margin due to the feed indicated that 15.0% CP in the diet offered greater economic gain for barrows from 60 to 100 kg. The results indicate that dietary protein changes, with main principal amino acids supplied not impaired the barrows performance. The creation and segregation conditions of commercial farm system in growing and finishing phases need considerations. Small variations between amino acids did not affect performance of barrows in the growing and finishing phases if the requirements of digestible lysine and others amino acids are maintained close to the indicated minimal relation.

The current objective was to expand on previous research using the Cobb MV × Cobb 500 to determine its finisher digestible Lys (dLys) requirement (Req ; d 28–41), as well as the effect of feeding varying finisher dLys levels on performance, processing, and economics. This was a 2 Sex (male or female) × 8 dLys factorial arrangement, wherein the experimental diets consisted of a practical control; (PRAC-CON ; 0.94% dLys) and 7 other diets with varying dLys concentrations (0.72%, 0.80%, 0.88%, 0.94%, 1.02%, 1.10%, and 1.18%) Chicks were fed common starter (1.28% dLys) and grower diets (grower 1 and 2 dLys were 1.18 and 1.08%, respectively). In general, males had improved performance versus females while females had increased processing yield (% of live weight) vs. males. Also, increasing finisher dLys resulted in improvements in performance and processing metrics, regardless of sex. Quadratic regression (QR ; 95% of vertex) and linear and quadratic broken line (LBL; QBL) models were utilized to estimate dLys Req for each sex. The estimated dLys Req range for females was 0.752-1.292% and males, 0.748 to 1.320%, when using all models. An economic model determined 1.10% finisher dLys to be most profitable. These data demonstrate that increasing finisher dLys can improve Cobb MV × Cobb 500 performance and processing; however, the optimal dLys Req can vary depending on sex, regression model, response parameter, and economics. [ABSTRACT FROM AUTHOR]

An experiment was conducted to evaluate the effect of dietary digestible lysine concentration on productive performance, egg quality, and blood metabolites in laying hens. A completely randomized block design was performed with 5 treatments and 6 replicates of 8 Hy-line W-36 hens each, from 32 to 44 wk of age. The treatments were 5 digestible lysine concentrations (0.657, 0.707, 0.757, 0.807, and 0.857% of diet). Feed intake was significantly increased with each increment in dietary digestible lysine concentration. Significant improvement in egg production, egg weight, egg mass, Haugh unit, and FCR were observed by an increase in lysine intake. Dietary lysine concentration did not have a significant impact on percentage of egg components, specific gravity, eggshell thickness, DM, and protein constituents of eggs. Dietary digestible lysine concentration did not have a significant effect on triglyceride, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), uric acid, and total protein in plasma. The digestible lysine requirements for optimal egg production, egg mass, and egg weight (32 to 44 wk of age), based on the linear broken-line regression analysis, were 814, 810 and 778 (mg/\b/d), respectively. Whereas, these values were 4, 3.9, and 6 percent less than those estimated by the quadratic broken-line model, respectively. [ABSTRACT FROM AUTHOR]

Dois ensaios foram conduzidos para se avaliarem os efeitos de níveis de lisina digestível em rações, mantendo ou não a relação aminoacídica, sobre o desempenho de frangos de corte dos 22 aos 42 dias, criados em ambiente de termomeutralidade. No ensaio 1, foram utilizados 210 frangos de corte machos Avian Farms com peso inicial médio de 662,5 g e, no ensaio 2, 168 frangos com peso inicial médio de 623,7 g. Em ambos os ensaios, o delineamento experimental foi o inteiramente casualizado; no ensaio 1, as aves foram distribuídas em cinco tratamentos (níveis de lisina digestível em rações convencionais) e seis repetições, com sete aves cada e, no ensaio 2, em quatro tratamentos (níveis de lisina em rações mantendo a relação aminoacídica) e seis repetições, com sete aves cada. Nos ensaios 1 e 2, os níveis de lisina digestível da ração influenciaram de forma linear crescente o ganho de peso e a conversão alimentar. No ensaio 1, observou-se efeito linear crescente dos tratamentos sobre o peso absoluto da carcaça. Não foi observado efeito dos tratamentos sobre o peso relativo da carcaça e os pesos absoluto e relativo de cortes nobres e de gordura abdominal. No ensaio 2, os pesos absoluto e relativo do peito e da coxa aumentaram linearmente, enquanto o peso absoluto da sobrecoxa elevou de forma quadrática até o nível de 0,955% de lisina. O peso relativo da sobrecoxa e os pesos absoluto e relativo da gordura abdominal não foram influenciados pelos tratamentos. Concluiu-se que frangos de corte machos Avian Farms na fase de 22 a 42 dias de idade, mantidos em ambiente de termomeutralidade, exigem no mínimo 1,015 e 1,075% de lisina digestível na ração convencional e na ração mantendo a relação aminoacídica, respectivamente, correspondente a um consumo estimado de 28 g de lisina digestível.Two trials were conducted to evaluate the effects of increasing dietary digestible lysine levels, maintaining or not the amino acid relation, on performance of broilers from 22 to 42 days old on thermoneutral environment. Two hundred and ten male broilers (averaging initial weight of 662.5 g) and 168 broilers (averaging initial weight of 623.7 g) were assigned to a completely randomized experimental design in trials 1 and 2, respectively. In trial 1, the broilers were allotted to five treatments (digestible lysine levels in conventional diets) and six replicates of seven broilers. In trial 2, the broilers were allotted to four treatments (digestible lysine levels in diet maintaining amino acid relation) and six replicates of seven broilers. In both trials, linear effect of digestible lysine levels on body weight gain and feed:gain ratio were observed. In trial 1, the increasing dietary digestible lysine levels increased linearly absolute carcass weight. There was no effect of lysine levels on relative carcass weights and on absolute and relative weichts of abdominal fat. In trial 2, absolute and relative breast and thigh weights increased linearly, while the absolute drumstick data increased quadraticly up to 0.955% digestible lysine level. No treatment effects on relative drumstick weight and absolute and relative weights of abdominal fat was observed. It was concluded that male broilers, Avian Farms, in the period from 22 to 42 days old, require at least 1.015 and 1.075% digestible lysine in conventional diet or in a diet maintaining the amino acid relation, respectively. This corresponds to an intake of 28 g digestible lysine for birds on a thermoneutral environment.

Dois ensaios foram conduzidos para avaliar rações com diferentes níveis de lisina digestível, mantendo-se ou não a relação aminoacídica, para frangos de corte de 1 a 21 dias, criados em ambiente de termoneutralidade. Em ambos os ensaios, utilizou-se o delineamento experimental inteiramente casualizado. No ensaio 1, os frangos foram distribuídos em cinco tratamentos (0,92; 0,98; 1,04; 1,10 e 1,16% de lisina digestível, em ração convencional), oito repetições e dez aves por repetição, enquanto, no ensaio 2, foram distribuídos em quatro tratamentos (1,04; 1,10; 1,16 e 1,22% de lisina digestível, em rações mantendo a relação aminoacídica), oito repetições e dez aves por repetição. No ensaio 1, os tratamentos influenciaram o ganho de peso, o consumo de ração, que aumentaram de forma quadrática até os níveis de 1,13 e 1,11%, respectivamente, e a conversão alimentar, que reduziu até o nível de 1,14% de lisina. O peso absoluto da carcaça aumentou até o nível de 1,13% de lisina digestível. O peso relativo da carcaça e o peso absoluto da moela aumentaram, enquanto os pesos relativos do coração e os dos intestinos reduziram linearmente com os tratamentos. No ensaio 2, apesar do ganho de peso ter elevado de forma linear, o modelo LRP foi o que melhor se ajustou aos dados, estimando em 1,17% o nível de lisina, a partir do qual ocorreu um platô. Os tratamentos não influenciaram o consumo de ração, a conversão alimentar e os pesos absoluto e relativo dos órgãos, enquanto o peso absoluto de carcaça aumentou de forma linear. Concluiu-se que frangos de corte machos Avian Farm, no período de 1 a 21 dias, criados em ambiente de termoneutralidade, exigem no mínimo 1,14 e 1,17% de lisina digestível em ração convencional e em ração mantendo-se a relação aminoacídica, respectivamente.Two trials were conducted to evaluate the requirements of increasing dietary digestible lysine levels, maintaining or not the amino acids relation, for broilers from 1 to 21 days old, on thermoneutral environment. A complete randomized experimental design was used in both trials. In trial 1, broilers were allotted to five treatments (0.92, 0.98, 1.04, 1.10, and 1.16% digestible lysine levels, conventional diet), with eight replicates of ten birds. In trial 2, chicks were allotted to four treatments (1.04, 1.10, 1.16, and 1.22% of digestible lysine, in diets maintaining amino acid relation) with eight replicates of ten birds. In trial 1, effects of dietary lysine levels on body weight gain and feed intake, both increasing quadraticly up to 1.13 and 1.11% digestible lysine, respectively, were observed. There was significant treatment effect on feed:gain ratio, that decreased quadraticly up to 1.14% digestible lysine. Absolute carcass weight increased quadractily while relative carcass values and absolute weight of gizzard increased linearly with treatments. Relative weights of heart and intestines decreased linearly with the treatments. In trial 2, body weight gain also increased linearly with treatments, the LRP model better adjusted to data, where the 1.17% digestible lysine level was estimated. No effects of treatments on feed intake and feed:gain ratio were detected. Absolute carcass weight was linearly affected by the increasing dietary lysine levels. There was no effect of dietary lysine levels on absolute and relative weights of all evaluated organs. It was concluded that Avian Farms male broilers, in the period from 1 to 21 days, require at least 1.14 and 1.17% digestible lysine, in a conventional diet or of a diet maintaining the amino acid relation, respectively, on a thermoneutral environment.

Quarenta e oito leitões híbridos comerciais, machos castrados e fêmeas, com 5,5 ± 0,21 kg foram distribuídos em blocos ao acaso, com quatro tratamentos e seis repetições, para determinar a melhor concentração de lisina até os 11,9 ± 0,35 kg (fase inicial-1) e os efeitos subseqüentes até os 19,0 kg (fase inicial-2). A composição química das frações corporais e a deposição de tecido muscular na carcaça e no corpo vazio foram determinadas. As concentrações de lisina total utilizadas na primeira fase pós-desmame foram 1,16 a 1,46%. Não foi observado efeito na composição química do sangue e das vísceras, caracterizando a independência das concentrações de lisina. As respostas para acúmulo protéico e água da carcaça e do corpo vazio foram ascendentes com o aumento de lisina, caracterizando a maior eficiência na utilização e direcionamento do nutriente para a síntese protéica da musculatura esquelética. Na segunda fase, não foram observados efeitos, mas os animais que, anteriormente, receberam menores níveis de lisina tenderam acumular mais proteína e água na carcaça e no corpo vazio. Possivelmente, encontrando-se em déficit de lisina, fisiologicamente tolerável, a nova dieta supriu parte da demanda anterior, porém pode não ter atendido à demanda para síntese protéica dos animais que se encontravam em maior ascensão de síntese e acúmulo protéico na fase inicial-1. As respostas favoráveis ao aumento da concentração de lisina na dieta de leitões entre 5,5 e 11,9 kg de peso vivo recomendam novos estudos utilizando níveis de lisina superiores aos empregados, combinados com maiores níveis de energia metabolizável, a fim de estabelecer a eficiência máxima de deposição protéica. Estudos nas fases subseqüentes devem complementar informações de melhor aporte nutricional para o suíno.Forty eight commercial hybrids, barrows and females with 5.47 ± 0.21 kg, were allotted to a randomized block design with four treatments and six replications, to determine the best lysine level until 11.9 ± .35 kg and subsequent effects at 19.0 kg. The chemical composition of body fractions and the carcass and empty body accretion rates were determined. The studied digestible lysine levels in the nursery phase were 1.16 at 1.46%. No effects were observed on the chemical composition of the offal and blood, characterizing independence of lysine levels. The response to carcass and empty body accretion rates of protein and water was ascendant, as lysine levels increased, characterizing higher efficiency of utilization and direction of lysine for protein synthesis of the musculature. In the second phase, significant effects were observed, but the animals that were previously fed diet with smaller lysine levels tended to accumulate more protein and water in the carcass and empty body. Possibly, being in nutritional deficit, physiologically tolerate, the new diet provided the previous demand, but can not provide the demand for protein synthesis of the animals that were fed higher accretion rates of protein and synthesis ascent in the initial-1 phase. The positive responses for increasing lysine concentration in the diet of piglets from 5.5 to 11.9 kg suggest a need for new evaluations with lysine and metabolizable energy levels above the ones used, in order to establish the maximum efficiency of protein accretion rates. Studies in subsequent phases may add information of better nutritional levels for pig.

The influence of the energy and the standardized ileal digestible lysine (DLys) content of the diet on egg production and egg quality, was studied in brown-egg laying hens from 18 to 41 wk of age. The experimental design was completely randomized with 10 treatments organized as a 2 × 5 factorial with 2 energy concentrations (2,750 and 2,800 kcal AMEn/kg) and 5 levels of DLys (values varied from 0.66 to 0.78% and 0.67 to 0.79%, for the low and high energy diets, respectively). Each treatment was replicated 10 times (10 hens per replicate). The data were analyzed using the MIXED procedure of SAS with energy concentration and DLys content of the diets as main effects. In addition, the effects of the DLys on the variables studied were partitioned into its lineal and quadratic components. From 18 to 21 wk of age (pre-peak phase), diet composition had limited effects on egg production. From 22 to 41 wk of age (peak phase), however, an increase of 50 kcal AMEn/kg diet increased egg weight (P < 0.05) and tended to improve energy intake (P = 0.083) and feed conversion ratio (P = 0.074). An increase in DLys improved linearly (P < 0.001) egg production, egg weight, egg mass, feed conversion, and energy conversion ratio, and tended to increase BW gain (P = 0.074). Diet composition did not any affect egg quality trait except shell strength that increased linearly (P < 0.05) with increases in the DLys. Cumulatively (18–41 wk of age), egg weight increased (P < 0.05) as the energy and the DLys content of the diet increased. In summary, an increase in energy and DLys content of the diet had limited effects on egg production during the prepeak phase but improved egg production, feed conversion ratio, and BW gain during the peak phase. The data indicate that hens require at least 839 mg DLys/d to maximize egg production in the peak production phase. [ABSTRACT FROM AUTHOR]

This research evaluates standard ileum digestible (SID) lysine density in starter period in Ross 308 male broilers to better understand the impact of increase dietary SID lysine density in live weight performance. Six diets (6 replicates) in starter period with different levels of SID lysine density, 1.411% (150% NRC), 1.321% (140% NRC), 1.215% (130% NRC), 1.126% (120% NRC), 1.035% (110% NRC) and 0.945 (100% NRC, 1994) were used in a completely randomized experimental design. All diets were iso-caloric and iso-nitrogenous. As a result of this study, Broilers fed 1.321% SID lysine level diet, body weight in 21 d was increased by 90 g compared with standard group (P<0.05). Levels of SID lysine density had a significant effect on body weight in weeks 1, 2 and 3. Feeding broilers with 1.321% SID lysine in starter diet was significant highest in body weight at 7, 14 and 21 days of age. Treatment 1.321% SID lysine was significant highest body weight gain from 0 to 7, 0 to 14 and 0 to 21 days of age and treatment 1.413% was significant highest body weight gain from 8 to 14 days of age compared with standard treatment (P<0.05). The results of this study suggest that 1.321% SID lysine density (140% NRC) in starter period diet optimized live weight and growth of Ross 308 male broiler and increasing SID lysine level from 0.945 to 1.413%, improved live weight in quadratic model. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine lysine (Lys) requirements of two commercial strains, Ross 308 and Cobb 500, from 15 to 28d of age. Basal diet was formulated to be adequate in all nutrients except for Lys. Incremental levels of supplemental Lys were added to the basal diet generating six experimental treatments in a range from 0.60 to 1.20% digestible Lys. Birds were randomized across 48 floor pens (4 replicates and 12 birds in each replicate) in completely randomized design and each pen was fed one of six amino acid levels. Body weight gain, feed intake, feed conversion ratio, and digestible Lys intake responded quadratically to graded levels of digestible Lys, and interaction effects between Lys and strain were significant for all performance traits except for feed conversion ratio. Digestible Lys requirements were estimated using broken-line linear and broken-line quadratic models. In Ross 308, digestible Lys requirements for body weight gain and feed conversion ratio were estimated at 0.95 and 1.08% of diet, respectively, by broken-line linear model. Digestible Lys need for body weight gain was optimized at 1.05% of diet using broken-line quadratic model. In Cobb 500, Lys requirements for body weight gain and feed conversion ratio were estimated at 0.89 and 0.98% of diet, respectively, by broken-line linear model. Digestible Lys need for body weight gain and feed conversion ratio were optimized at 0.99 and 1.14% of diet using broken-line quadratic model.

The objectives of this experiment were to evaluate procedures that may be used to predict the concentration of standardized ileal digestible (SID) Lys in distillers dried grains with solubles (DDGS) fed to pigs and to evaluate the accuracy of a published equation to predict SID Lys in DDGS. Twenty-one sources of DDGS were analyzed (as-fed basis) for CP (23.8% to 33.6%; CV = 8.3%), Lys (0.69% to 1.17%; CV = 12.4%), and furosine (0.02% to 0.22%; CV = 91.4%). The concentration of reactive Lys (%, as-fed basis) was calculated as analyzed Lys (%) - furosine (%) + 0.32 x 0.40 and ranged from 0.47% to 1.15% (CV = 20.7%) in the 21 sources of DDGS. Twenty-one diets that each contained 60.0% of 1 source of DDGS as the sole source of CP and AA were formulated. An N-free diet was also formulated and was used to determine basal endogenous losses of CP and AA. Twenty-two barrows with an initial BW of 45.2 kg (SD = 3.1 kg) were fitted with a T-cannula in the distal ileum and allotted to a 22 x 10 Youden square design with the 22 diets and 10 periods. The SID of CP and AA were calculated for each source of DDGS. The SID of CP ranged from 69.8% to 79.6%, and the SID of Lys ranged from 45.3% to 74.1%. The concentration of SID Lys in the 21 samples of DDGS was highly related to the concentration of analyzed Lys (P < 0.001 ; r² = 0.849) and with the concentration of reactive Lys in the samples (P < 0.001; r² = 0.898). In contrast, the concentration of SID Lys in the 21 sources of DDGS was not related to the concentration of CP in the samples (P = 0.558; r² = 0.021). However, values for SID Lys were in good agreement with values predicted using a published prediction equation. In conclusion, analyzed Lys in DDGS, but not CP, may be used to predict the concentration of SID Lys in DDGS fed to pigs. However, analysis of furosine in addition to Lys and subsequent calculation of reactive Lys improve the prediction accuracy of digestible Lys concentration in DDGS. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the requirement for digestible lysine for broilers from 35 to 49 days of age. Two hundred and forty chicks with a mean weight of 44±1 g were used in a completely randomized design, made up of male and female chicks and 6 digestible lysine levels. Experimental diets were formulated to be isoenergetic and isonitrogenous. Fitted broken lines on different responses indicated break points at 0.93, 0.93 (for body weight), 0.98, and 0.92 for feed conversion ratio for male and female, respectively. The results showed that the digestible lysine requirement of male broilers for maximum breast yield percentage, plasma free lysine and antibody titer against Newcastle disease virus exceeded the range of lysine levels tested. Dietary lysine had a significant effect in increasing the plasma free lysine, albumin, total protein, immunoglobulin, antibody titer against sheep red blood cell, Newcastle disease virus and heterophil to lymphocyte ratio. In conclusion, lysine requirements of broilers for performance were lower than breast yield percentage and immune responses. Broken-line analysis showed that the concentrations of plasma free lysine were useful physiological indicators for determining the digestible lysine requirement of male and female broilers. Our results suggest that the estimated requirements based on exponential response curves were higher than estimated requirements obtained using a broken-line model. [ABSTRACT FROM AUTHOR]

There is little research data available on the digestible Lys requirement of broilers from 2 to 4 wk of age. Two experiments were conducted to determine the digestible Lys requirements of male and female Ross x Ross TP16 broilers from 14 to 28 d. Two diets (dilution and summit) consisting of corn, soybean meal, poultry by-product meal, and peanut meal were formulated to be adequate in all other amino acids. The dilution and summit diets were blended to create 9 titration diets. A control diet containing adequate Lys was used for comparison with the titration diets. A true Lys digestibility assay was conducted with cecectomized roosters to determine the values for the dilution (low) and summit (high) diets. True digestible Lys of the low and high dose-response diets were determined to be 0.84 and 1.21%, respectively. Body weight gain, feed intake, digestible Lys intake, digestible Lys intake:BW gain, feed conversion, and mortality were assessed during experimentation. Digestible Lys requirements were estimated using a quadratic broken-line model and a quadratic regression equation based on 95% of the optimum response. In experiment 1, the digestible Lys requirement for male Ross x Ross TP16 broilers was determined to be between 1.07 and 1.09% and 1.10 and 1.15%, for BW gain and feed conversion, respectively. in experiment 2, the digestible Lys requirement for female Ross x Ross TP16 broilers was estimated as 0.98% for BW gain determined with a quadratic broken-line model and 1.03 and 0.99% for feed conversion, respectively, using a quadratic regression equation based on 95% of the optimum response and the quadratic broken-line model. Digestible Lys requirements for male and female Ross x Ross TP16 broilers were estimated at 1.10 and 1.00%, respectively, based upon BW gain and feed conversion averaged for both statistical models. [ABSTRACT FROM AUTHOR]

The response of broiler chickens to two levels of endo-1,4-β xylanase (EC 3.2.1.8) and endo-1,3-β glucanase (EC 3.2.1.6) combination (with and without), three levels of digestible lysine (0.8%, 0.9% and 1.0% with the applicability of ideal protein concept) and two levels of cottonseed meal (CSM; 20% and 30%) were evaluated in 2 × 3 × 2 factorial arrangement. A total of 2448 male Hubbard broiler chicks were fed on practical vegetable-based mash diets having 2750 kcal metabolizable energy (ME) per kg and 18.5% crude protein (CP) from the age of day 1 to 42. The supplemental enzyme had minimum 1100 units of endo-1,4-β xylanase and 100 units of endo-1,3-β glucanase/kg of finished diet. The addition of CSM at 30% resulted in increasing arginine to lysine ratio. A decrease in dressing and breast percentages were observed by the addition of 30% CSM. The digestible lysine at 1.0% decreased the body weight (BW) gain and lowered the mortality during day 1 to 21 whereas the BW gain and feed:gain ratio were unaffected among the three digestible lysine levels during day 1 to 42. The antibody titres against Newcastle and infectious bursal disease viruses were improved with the increasing levels of digestible lysine. The enzyme supplementation improved the apparent ME and digestibility coefficient of nitrogen when it was used with 30% CSM. No effect of enzyme, lysine, CSM or their interactions was observed on serum iron, gizzard and liver weights or abdominal fat percentage. The results showed that increasing digestible lysine improved the antibody titre but did not improve the growth performance and carcass characteristics; supplemental enzyme failed to show any improvement in performance of birds fed on CSM-based diets. [ABSTRACT FROM AUTHOR]

The optimum biological digestible lysine level in laying hens past production peak was determined in a 7-wk trial using diets with different digestible lysine levels. A total of 336 Isa Babcock B-300 laying hens (32 wk old) housed in cages were distributed randomly in seven treatments with four replicates each and 12 hens per replicate. The basal diet was based on sorghum, soybean and sesame meal, contained 15 % crude protein and 0.50 % digestible lysine. Six experimental diets were formulated with digestible lysine levels ranging from 0.50 % to 0.74 %; L-lysine HCl was added to increase lysine levels by 0.04 % in each successive diet. Production variable data were recorded weekly: average egg weight, egg mass, feed conversion and feed intake. At 3.5 weeks, egg component variable data (percentage albumen, yolk and shell) were collected. Data were analyzed using a multivariate analysis with the principal components technique, and a regression analysis with quadratic transformation. The principal components exhibited a quadratic effect (P<0.01), with egg mass (0.899) having a greater effect on digestible lysine requirements than other components, such as egg weight (0.590). Egg mass was thus used to calculate the optimum biologically digestible lysine level requirement for the studied laying hens, which was 0.659 %, or 12.14 mg lysine per gram egg mass. [ABSTRACT FROM AUTHOR]

Abstract: Response of broiler chickens to 2 levels of endo-1,4-β xylanase (EC 3.2.1.8) and endo-1,3-β glucanase (EC 3.2.1.6) cocktail (with and without), 3 levels of digestible lysine (8.0, 9.0 and 10.0gkg−1 with the applicability of ideal protein concept), and 2 levels of sunflower meal (SFM; 200 and 300gkg−1) were evaluated in the present experiment. The factorial design of 2×3×2 using 2448 one-day-old straight-run Hubbard broiler chicks was used to evaluate the effect of two levels of enzymes, 3 levels of digestible lysine and 2 levels of SFM in practical vegetable based mash diets having 11.51MJME and 190gCPkg−1 from 1 to 42d of age. The BW gain was improved linearly (P≤0.001) with the increasing level of digestible lysine during 1–21d and 22–42d of age. The gain:feed was improved linearly (P≤0.001) with the increasing digestible lysine during 1–21d and a quadratic effect of digestible lysine was noted during 1–42d where 9.0 and 10.0g digestible lysine kg−1 of diet responded similar for gain:feed. Enzyme supplementation at 300gSFMkg−1 improved BW gain (P≤0.008) and gain:feed (P≤0.048) during 1–21d. When 10.0g digestible lysine kg−1 of diet was used at 2 levels of SFM, gain:feed was improved (P≤0.013) during 1–21d. However, this interaction was not significant on other performance parameters either at 21d or at 42d of age. The enzyme supplementation decreased the feed intake (P≤0.019) by 4.67% and improved gain:feed by 5.53% (P≤0.012) during 1–42d without affecting BW gain. The main effect of SFM was not significant for live performance or carcass response at any stage. The depression in breast weights at 42d due to 300g SFM or 8.0g digestible lysine kg−1 of diet was compensated by the enzyme addition (a significant enzyme×SFM effect). No significant effect of enzyme, SFM, digestible lysine or their interactions was observed on apparent metabolizable energy of the diets. Coefficient of total tract apparent digestibility of nitrogen was improved by the addition of enzyme to 10.0g digestible lysine kg−1 of diet or addition of digestible lysine to high SFM. The results of the present study revealed a positive response of enzyme addition in low nutrient density and high SFM diets. Moreover, digestible lysine is not suggested to be lowered than 10.0g during 1–21d and it may be reduced to 9.0gkg−1 if a single diet having high level of SFM is planned to be offered during 1–42d. [Copyright &y& Elsevier]

The response of broiler chickens to 2 levels of endo-1,4-β xylanase and endo-1,3-β glucanase combination (with and without), 3 levels of digestible Lys (0.8, 0.9, and 1.0%), and 2 levels of canola meal (CM; 20 and 30%) were evaluated in 2 × 3 × 2 factorial arrangement. A total of 2,448 male Hubbard broiler chicks were fed on practical mash diets having 2,750 kcal of ME·kg-1 and 19.6% CP from 1 to 42 d of age. The BW gain was significantly reduced when 30% CM was added in the diets during 1 to 21 d. Feed:gain and mortality were also observed to be high. No significant effect of enzyme addition or Lys level was observed on feed intake, BW gain, feed:gain, and mortality during the starter phase. When the data were pooled for 42 d, BW gain and feed:gain were unaffected by enzyme addition or Lys levels. A depression in breast weight was observed due to 30% CM or 0.8 and 0.9% digestible Lys at 43 d. Leg weights were significantly depressed by enzyme addition or increasing digestible Lys to 1.0% of the diets. The AME, nitrogen digestibility, and antibody titers against Newcastle and infectious bursal diseases were also unaffected by the dietary treatments. In conclusion, the 30% CM is not recommended in broiler diets especially during starter phase (1 to 21 d). However, the CM may be used up to 30% of the diets during finishing phase. The digestible Lys can be lowered to 0.8% when amino acids in proportion to digestible Lys follow the ideal AA ratio. The glucanase and xylanase cocktail have no pronounced effect on the growth performance, nutrient digestibility, and carcass characteristics. [ABSTRACT FROM AUTHOR]

Metabolism and growth trials were conducted to study true digestible methionine (tMet) and lysine (tLys) requirements for growing Lohmann egg-type cockerels and to evaluate the effects of 2 dietary tMet levels and 4 tLys levels in a factorial arrangement on growth, nitrogen balance and serum biochemical indices. In the metabolism trial, 20 caecectomised and anus-stitch-surgery healthy adult male birds were used to determine the true digestibility of Met and Lys. In the growth trial, 30 Lohmann egg-type cockerels were allocated to each of 32 floor pens (total 960 birds). During the 0-6 week starting period, 2 levels of tMet (0.37, 0.42%) and 4 levels of tLys (0.84, 0.92, 1.00, 1.08%) were fed to birds, while during the 7-10 week finishing period tMet levels were 0.29% and 0.33% and tLys levels 0.73%, 0.80%, 0.87% and 0.94%, respectively. The results showed that the survival rate in all treatments was 100% during the whole period, indicating that levels of tMet and tLys in the experiment had no influence on the rate. Considering the average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), nitrogen retention ratio (N-retention), and serum uric acid (UA) content of all treatments together with Met and Lys digestibility, optimal tMet and tLys levels were 0.42%/1.00% (T7) for the starter diet and 0.33%/0.94% (T8) for the finisher diet. Although serum growth hormone (GH), thyroxine (T4) and triiodothyronine (T3) contents of chicks indicated significant differences among the treatments during the whole period, the relationship between dietary tMet and tLys levels and serum GH, T4 and T3 contents seemed irregular. The results also showed that there were interactions between tMet and tLys, and that this interaction had influenced ADG, ADFI, FCR, N-retention, serum UA and hormone contents significantly during the whole period. [ABSTRACT FROM AUTHOR]

Four experiments were conducted to study the changes in the digestible lysine (DLYS) and sulfur amino acid (DSAA) requirements of broilers during the first 21 d posthatching. Cobb 500 by-product male broilers were fed corn-corn gluten meal-soybean meal diets formulated to be isocaloric and isonitrogenous. Five graded levels of either Lys or SAA were used, varying from 0.78 to 1.28% DLYS (experiments 1 and 2) and from 0.61 to 1.08% DSAA (experiments 3 and 4). Body weight gain (BWG) and gain:feed ratio (GF) were calculated at 4, 7, and 21 d. The DLYS requirements based on BWG varied from 0.98 at 4 d of age to 1.01% at 21 d in experiment 1 and from 0.95 at 4 d of age to 0.99% at 21 d, in experiment 2. Based on GF, the DLYS requirement varied from 1.08 to 1.10% in experiment 1, and from 0.98 to 0.94% in experiment 2 at 4 and 21 d, respectively. The estimated DSAA requirements for BWG varied from 0.83 to 0.88% or from 0.71 to 0.75% for 4 and 21 d in experiments 3 and 4, respectively. For GF, the DSAA decreased slightly from 0.88% at 4 d to 0.83% at 21 d in experiment 3, but did not change in experiment 4 (0.81%). Minimal changes in the DLYS or DSAA estimated requirements occurred during the first 21 d of age, which suggests that the recommended DLYS and DSAA levels determined at 21 d of age appear to be adequate to meet chick needs for the first week of age. [ABSTRACT FROM AUTHOR]

In order to know the requirements of digestible lysine and sulfur amino acids in White Leghorn hens, two experiments were conducted. Two hundred and forty caged laying hens, Isa Babcock B-300 line, were used in each experiment. The birds were 24 weeks old. Completely randomized designs with 5 treatments were used in both experiments. In Experiment 1, the treatments were 5 amounts of digestible lysine (0.47%, 0.57%, 0.67%, 0.77% and 0.87%), and in Experiment 2 the treatments were 5 amounts of digestible methionine + cystine (0.41%, 0.47%, 0.53%, 0.59% and 0.65%). The basal diets with 15.69% crude protein were based on sorghum + soybean and corn yellow gluten meal. In order to reach the required amino acid levels in the experimental diets, HCl L-lysine and DL-methionine were added. In each experiment, the studied productive parameters that were analyzed by multivariate variance analysis were: laying percentage, egg weight, egg mass per bird per day, feed consumption and feed conversion. The results obtained through 10 weeks of experimentation showed a quadratic effect (P < 0.01), the optimum levels in order to reach maximum productivity were 0.728% of digestible lysine and 0.615% of digestible methionine + cystine with a daily feed consumption per bird of 655 mg of lysine and 553 mg of sulfur amino acids. These results suggest that the ideal relationship for maximum productivity in layer hens is: lysine at 100% and methionine + cystine at 84.4%. [ABSTRACT FROM AUTHOR]

Presents abstracts of several studies on nonruminant pig nutrition. "Advantages of Formulating Diets Based on Net Energy on Pig Performance, Carcass Characteristics and Production Economics," by M. Rademacher and L. Hagemann; "Energy, Protein, and Amino Acid Digestibility in Different Sources of Rice Bran for Growing Pigs," by C. Kaufmann and colleagues; "Comparison of a Diet Containing Food Waste With a Corn/Soybean Diet Fed to Swine," by J. Jones, M. L. Westendorf and J. E. Wohlt.

Presents abstracts of several studies on nonruminant pig nutrition. "Advantages of Formulating Diets Based on Net Energy on Pig Performance, Carcass Characteristics and Production Economics," by M. Rademacher and L. Hagemann; "Energy, Protein, and Amino Acid Digestibility in Different Sources of Rice Bran for Growing Pigs," by C. Kaufmann and colleagues; "Comparison of a Diet Containing Food Waste With a Corn/Soybean Diet Fed to Swine," by J. Jones, M. L. Westendorf and J. E. Wohlt.

Presents abstracts of several studies on nonruminant pig nutrition. "Advantages of Formulating Diets Based on Net Energy on Pig Performance, Carcass Characteristics and Production Economics," by M. Rademacher and L. Hagemann; "Energy, Protein, and Amino Acid Digestibility in Different Sources of Rice Bran for Growing Pigs," by C. Kaufmann and colleagues; "Comparison of a Diet Containing Food Waste With a Corn/Soybean Diet Fed to Swine," by J. Jones, M. L. Westendorf and J. E. Wohlt.

A digestibility experiment was carried out with 140 Ross-broiler chickens (age 24 days) to determine coefficient of ileal apparent digestibility (CIAD) of amino acids in meat and bone meal (MBM), full-fat soyabeans (FFSs), soyabean cake and meal, full-fat rapeseeds, and rapeseed cake and meal. The birds were fed semi-purified diets which contained protein feedstuffs as a sole protein source and chromium mordanted straw as an indigestible marker. The CIAD of nutrients were assessed using the slaughter technique.A 37-day growth experiment was carried out with 2880 Ross-broiler chickens to compare feed formulation systems based on apparent ileal digestible or total lysine content. Three barley based diets were formulated to be similar in total lysine content (9.5 g/kg feed). Diet 1 contained soyabean meal (SBM) (280 g/kg DM), Diet 2 SBM (180 g/kg DM) and rapeseed meal (RSM) (171 g/kg DM) and Diet 3 a combination of SBM (78 g/kg DM), RSM (172 g/kg DM) and MBM (87 g/kg DM). The composition of Diets 4 and 5 was similar to that of diets 3 and 4, respectively, except that they were supplemented with l-lysine–HCl to obtain a similar apparent ileal digestible lysine content as in Diet 1 (7.9 g/kg feed). The total lysine content of Diets 4 and 5 was 10 g/kg feed. Furthermore, Diet 1 was supplemented with l-lysine–HCl to obtain Diet 6, in which the total and apparent ileal lysine contents were 10 and 8.5 g/kg feed, respectively.CIAD of lysine, methionine, threonine and cystine were respectively 0.60, 0.66, 0.48 and 0.34 for MBM; respectively 0.81, 0.75, 0.68 and 0.67 for FFSs; respectively 0.86, 0.86, 0.76 and 0.62 for soyabean cake; respectively 0.85, 0.84, 0.74 and 0.63 for SBM; respectively 0.59, 0.59, 0.43 and 0.53 for full-fat rapeseeds; respectively 0.68, 0.81, 0.64 and 0.53 for rapeseed cake; and respectively 0.63, 0.75, 0.54 and 0.43 for RSM.Final weight and growth rate were highest when digestible lysine based feed formulation was used compared to that based on total lysine (P<0.001). The increase in final weight was largest for diet containing MBM and formulated based on digestible lysine (P<0.001). In addition, the proportion of breast muscle of total live-weight and weight of breast muscle increased (P<0.05) in animals fed diets formulated on the basis of digestible compared to total lysine. However, diet formulation based on digestible lysine impaired feed conversion ratio compared to that of total lysine for birds fed SBM as the sole source of supplementary protein compared to diets containing rapeseed or MBM (P<0.01). Growth rate and final weight were higher in birds fed diets containing SBM alone compared to those also containing RSM and MBM (P<0.001). In addition, the effect of diet formulation based on digestible lysine on performance results of broilers was more obvious in males than females (P<0.05). The results indicated that formulation of diets based on a digestible lysine was better than that based on total lysine when diets contained protein sources of low amino acid digestibility such as meat and bone and RSMs. [Copyright &y& Elsevier]