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With today's challenges regarding antibiotic resistance and the importance of the implementation of prudent use of antibiotics, fast and reliable diagnostic tools for bacterial infections and subsequent antimicrobial susceptibility testing are of utmost relevance. Isothermal microcalorimetry (IMC) is a broadly applicable method, with which metabolic heat flow in reproducing bacteria can be measured in real time. To the best of the authors' knowledge, this is the first report on examination of 124 urine samples from feline and canine urinary tract infection with an IMC-based prototype instrument. A concentration-dependent time of peak heat flow by dilution series with Escherichia coli and Enterococcus faecalis reference strains demonstrated the general good performance of the prototype for detection of these bacteria. With diagnostic culture being set as a gold standard, the diagnostic sensitivity of IMC compared to bacteriological culture was 80 %, the diagnostic specificity was 97 %. With a Cohens' kappa value (κ) of 0.80, the two methods show good concordance. The results from our study demonstrate that the IMC technology is suitable to allow reliable, but much faster detection of bacteria than conventional culture, especially for Escherichia coli. Thus, implementing IMC technology could markedly speed up the bacteriological diagnostic process in veterinary medicine., Competing Interests: Declaration of Competing Interest We declare that we have no competing interests., (Copyright © 2023. Published by Elsevier B.V.)

The dairy industry uses enzymes to make cheese, alter product flavor, and eliminate lactose. The activities of these enzymes have been measured in clear buffered solutions, but because of the limitations of spectrophotometric methods, enzyme activities have not been measured in opaque or colored dairy products where they are used. Isothermal titration calorimetry (ITC) can be used to determine reaction kinetics in opaque and colored solutions by measuring the heat rate (thermal power) from enzyme-catalyzed reactions as a function of time. This study used ITC to measure β-galactosidase activity in opaque solutions of milk, sweet whey, sweet whey permeate, acid whey, and acid whey permeate with 2 β-galactosidase (Enzyme Commission number 3.2.1.23) isozymes derived from Aspergillus oryzae and Kluyveromyces lactis. The components of the dairy fluids alter the enzyme kinetics and reaction thermodynamics, and the reactions catalyzed by the 2 homologues differ as shown by differing thermodynamic profiles. The study demonstrates that ITC can be used to measure enzyme activity in opaque and colored dairy fluids and identify reactions by their thermodynamic properties., (© 2023, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Three experiments were conducted to determine the effect of different dietary net energy (NE) and AMEn ratios (NE:AMEn) on performance, egg quality, and heat production (HP) in laying hens. In experiment 1, 62 Hy-Line Brown hens were fed 2 treatments with 31 replicates from 44 to 54 wk of age. In experiment 2, 600 hens of the same strain were fed 3 treatments from 22 to 42 wk of age with 10 replicates. Both used a completely randomized design. Diets were based on corn, wheat, wheat bran, barley, soybean meal, canola meal, meat and bone meal, and canola oil. In both experiments, the NE:AMEn ratio of diets was increased with higher oil inclusion compared with T1 controls. The AMEn (kcal/kg), NE (kcal/kg), ether extract (g/kg), and CP (g/kg), respectively, on a DM basis in experiment 1 was T1: 3,011, 2,288, 42, 202 and T2: 3,023, 2,374, 81, 203; and in experiment 2, T1: 3,026, 2,324, 25, 187; T2: 2,949, 2,315, 61, 185; and T3: 3,026, 2,397, 73, 181. Increasing the ratio of NE:AMEn decreased feed intake (P < 0.001) and increased egg mass (P < 0.05) in experiment 2 and increased egg weight (P < 0.01), decreased feed conversion ratio (P < 0.01), increased egg albumen % (P < 0.001), and decreased yolk % (P < 0.05) and shell % (P < 0.05) compared with T1 controls in both experiments. Haugh units and yolk color scores were increased with high NE:AMEn in both experiments (P < 0.001; P < 0.01). Experiment 3 was conducted in calorimetry chambers to measure HP in birds fed experiment 2 diets. Increasing the NE:AMEn increased total retained energy (RE), RE as fat, and RE in the body (kcal/kg BW 0.75 /D) and NE:AME. The results indicate that using oil to increase the NE:AMEn results in improved performance and egg quality and more efficient energy utilization., (Copyright © 2020. Published by Elsevier Inc.)

There is evidence indicating that using the current UK energy feeding system to ration the present sheep flocks may underestimate their nutrient requirements. The objective of the present study was to address this issue by developing updated maintenance energy requirements for the current sheep flocks and evaluating if these requirements were influenced by a range of dietary and animal factors. Data (n = 131) used were collated from five experiments with sheep (5 to 18 months old and 29.0 to 69.8 kg BW) undertaken at the Agri-Food and Biosciences Institute of the UK from 2013 to 2017. The trials were designed to evaluate the effects of dietary type, genotype, physiological stage and sex on nutrient utilization and energetic efficiencies. Energy intake and output data were measured in individual calorimeter chambers. Energy balance (Eg) was calculated as the difference between gross energy intake and a sum of fecal energy, urine energy, methane energy and heat production. Data were analysed using the restricted maximum likelihood analysis to develop the linear relationship between Eg or heat production and metabolizable energy (ME) intake, with the effects of a range of dietary and animal factors removed. The net energy (NEm) and ME (MEm) requirements for maintenance derived from the linear relationship between Eg and ME intake were 0.358 and 0.486 MJ/kg BW0.75, respectively, which are 40% to 53% higher than those recommended in energy feeding systems currently used to ration sheep in the USA and the UK. Further analysis of the current dataset revealed that concentrate supplement, sire type or physiological stage had no significant effect on the derived NEm values. However, female lambs had a significantly higher NEm (0.352 v. 0.306 or 0.288 MJ/kg BW0.75) or MEm (0.507 v. 0.441 or 0.415 MJ/kg BW0.75) than those for male or castrated lambs. The present results indicate that using present energy feeding systems in the UK developed over 40 years ago to ration the current sheep flocks could underestimate maintenance energy requirements. There is an urgent need to update these systems to reflect the higher metabolic rates of the current sheep flocks.

Our aim was to compare the energy balance estimated (EBest) according to equations published by various energy feeding systems (German Society for Nutrition Physiology, French National Institute for Agricultural Research, and US National Research Council) and the EB calculated by use of calorimetrically measured heat production (EBhp) of 20 high-yielding (≥10,000 kg/305 d) German Holstein cows at -4 (pregnant, nonlactating) and 2 wk (early lactation) relative to parturition. In addition to heat production, feed and water intake, physical activity (including standing-lying behavior), body weight, body condition score, body temperature, plasma concentrations of fatty acids and β-hydroxybutyrate, milk yield, and milk composition were measured to characterize the metabolic status. The EBhp was balanced [2.74 ± 4.09 MJ of metabolizable energy (ME)/d; ±standard error] before calving, but strongly negative (-84.7 ± 7.48 MJ of ME/d) at wk 2 of lactation. At both time points, EBhp and EBest differed significantly. On average, the equations overestimated the antepartum EB by 33 MJ of ME/d and underestimated the postpartum negative EB by 67 MJ of ME/d, respectively. Because the same ME intake and energy-corrected milk values were used for calculation of EBest and EBhp in our study, we considered that the factors (0.488 to 0.534 MJ of ME/kg 0.75 ) currently used to calculate the ME requirements for maintenance probably underestimate the needs of high-yielding dairy cows, particularly during early lactation. In accord, heat production values determined under standard conditions of thermoneutrality and locomotion restriction amounted to 0.76 ± 0.02 MJ of ME/kg 0.75 (4 wk antepartum) and 1.02 ± 0.02 MJ of ME/kg 0.75 (2 wk postpartum), respectively. The expected positive correlation between EBhp and DMI was observed in pregnant cows only; however, a bias of 26 MJ of ME/d between mean actual energy intake and ME intake predicted according to German Society for Nutrition Physiology was found in cows at wk 4 antepartum. At both investigated time points, mobilization of tissue energy reserves (reflected by plasma fatty acid concentration) was related to EBhp. In early lactating cows, metabolic body weight (kg 0.75 ) and the percentage of milk fat showed the strongest correlation (correlation coefficient = -0.70 and -0.73) to EBhp. Our findings must be taken into account when experimental data are interpreted because the true energy status might be significantly overestimated when EBest is used., (The Authors. Published by FASS Inc. and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

The objective of this experiment was to find out the effect of lemon leaves on energy and C-N balances, methane emission, and milk performance in dairy goats. Lemon leaves were used to replace alfalfa as forage in a diet for Murciano-Granadina goats. Ten Murciano-Granadina dairy goats (44.1 ± 4.47 kg of BW) in late lactation (185 ± 7.2 d) were selected in a crossover design experiment, where each goat received 2 treatments in 2 periods. One group was fed a mixed ration with 450 g of pelleted alfalfa per kilogram of DM (ALF diet) and, the other group replaced alfalfa with 450 g of pelleted lemon leaves per kilogram DM (LEM diet). The concentrate was pelleted, being the same for the two groups (forage to concentrate ratio was 45/55). The goats were allocated to individual metabolism cages. After 14 d of adaptation, feed intake, total fecal and urine output, and milk yield were recorded daily over a 5-d period. Then, gas exchange measurements were recorded individually by an open-circuit indirect calorimetry system using a head box. Higher dietary lipids in LEM diet reduced DMI (200 g/d) and energy intake (251 kJ/kg of BW0.75), although no differences between treatments were observed for ME intake (998 kJ/kg of BW0.75, on average) and oxidation of nutrients (64% and 25% for carbohydrates and fat oxidation, respectively, on heat production from oxidation basis). Greater (P < 0.05) milk fat values for C18:2n6t and CLA 9c11t + 9t11c were found in LEM compared with ALF diet. Goats fed LEM diet produced significantly fewer CH4 emissions than ALF diet (18%). Likewise, the use of lemon leaves as forage reduced the amount of CH4 in 2.7 g/kg of milk. Results suggest that lemon leaves are effective in reducing CH4 emission without detrimental effect on milk yield.

Cattle grazing wheat pasture in the southern Great Plains are sometimes fed an energy supplement; however, the benefits of supplementation on nutrient balance, energy metabolism, and greenhouse gas emissions have not been elucidated. Therefore, we used 10 British crossbred steers (206 ± 10.7 kg initial BW) in a respiration calorimetry study to evaluate the effects of energy supplementation on energy losses, N balance, and nutrient digestibility of steers fed green-chopped wheat forage. The study design was an incomplete replicated 4 × 4 Latin square with treatments in a 2 × 2 factorial arrangement. Steers ( = 8) were assigned to 1 of 2 BW blocks (4 steers per block) with dietary factors consisting of 1) no supplementation (CON) or supplemented with a steam-flaked corn-based energy supplement (that also contained monensin sodium) at 0.5% of BW daily (SUP) and 2) NEm intakes of 1 times (1x) or 1.5 times (1.5x) maintenance. Wheat forage was harvested daily and continuously fed as green-chop to steers during the 56-d study. There were no differences ( ≥ 0.32) between CON and SUP for OM (78.3 vs. 80.7%, respectively) or NDF (68.3 vs. 64.8%, respectively) digestibility. At the 1.5x level of intake, there was no difference ( ≥ 0.16) in energy lost in feces (4.27 vs. 3.92 Mcal/d) or urine (0.58 vs. 0.55 Mcal/d), heat production (8.69 vs. 8.44 Mcal/d), or retained energy (3.10 vs. 3.46 Mcal/d) between supplementation treatments. Oxygen consumption (1,777 vs. 1,731 L/d; = 0.67) and CO production (1,704 vs. 1,627 L/d; = 0.56) of CON and SUP steers, respectively, were not different; however, SUP steers tended to have ( = 0.06) lower CH production (115 vs 130 L/d) than CON steers. Methane, as a proportion of GE intake, was similar for CON (6.87%) and SUP (6.07%; = 0.18), as was the ME:DE ratio ( = 0.24; 86.3% for CON and 87.9% for SUP). Fractional N excretion in urine and feces, as a proportion of total N excreted ( ≥ 0.84) or N intake ( ≥ 0.63), was not different between treatments. Calculated NEm and NEg values for CON were 1.76 and 1.37 Mcal/kg DM, respectively, whereas the NEm and NEg values for the SUP treatment were 2.32 and 1.61 Mcal/kg DM, respectively. Calculated NE values for steers fed additional energy were approximately 17.5% greater than the expected difference in energy content. This was probably the result of the inconsistent response at the 1x DMI level. Under these circumstances, energy supplementation did appear to enhance NEm and NEg value of the supplemented wheat forage diet.

The objective of the present study was to examine the effect of dietary forage proportion (FP) on metabolizable energy (ME) requirement for maintenance (MEm) and the efficiency of ME use for lactation (kl) in lactating dairy cows. Data used were derived from 32 calorimetric chamber experiments undertaken at our institute between 1992 and 2010, including data from 818 Holstein-Friesian cows (HF), 50 Norwegian Red cows, and 62 crossbred cows (Jersey × HF or Norwegian Red × HF). Animals were offered forage-only rations (n=66) or forage and concentrate rations (n=864) with FP ranging from 18 to 100% (dry matter basis). The effect of FP was evaluated by dividing the whole data set into 4 groups according to the FP ranges, categorized as FP <30%, FP=30 to 59%, FP=60 to 99%, and FP=100%. The MEm for individual cows was calculated from heat production minus energy losses from inefficiencies of ME use for lactation, energy retention and pregnancy, and kl was obtained from milk energy output adjusted to zero energy balance (El(0)) divided by ME available for production. Increasing FP significantly reduced ME intake and milk energy output, although the differences between the 2 low FP groups were not significant. However, increasing FP significantly increased the ratio of heat production over ME intake and MEm (MJ/kg(0.75)), with the exception that the increases did not reach significance in heat production/ME intake between FP <30% and FP=30 to 59%, or in MEm between FP=60 to 99% and FP=100%. However, the FP had no significant effect on the kl values, which were similar among the 4 groups of cows. The effect of FP was also evaluated using the linear mixed regression technique relating El(0) to ME intake. The results demonstrated that with a common regression coefficient (slope), the regression constants (intercepts) taken as net energy requirement for maintenance significantly increased with increasing FP. However, the increase between the 2 high FP groups did not research significance. It is concluded that increasing diet FP had no effects on kl but significantly increased maintenance energy requirement (MJ/kg(0.75)). These results indicate that using the current energy feeding systems to ration dairy cows managed under low input systems may underestimate their nutrient requirements, because the majority of feeding systems adopted globally do not differentiate the maintenance energy requirements between low and high forage input systems., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The net energy (NE) value may be a better measure than apparent metabolizable energy (ME) of the effect of supplemental phytase on energy utilization in broilers. The present study was conducted to assess the impact of 3 microbial phytases supplemented at an unconventionally high level (1,000 FTU/kg feed) on performance and NE of broilers using the indirect calorimetric method (IC). Four treatments included: 1) Control, formulated to be deficient in ME (12.35 MJ/kg in the starter diet; 12.56 MJ/kg in the grower diet), calcium (0.72% in the starter diet; 0.60% in the grower diet), and available phosphorus (0.25% in the starter diet; 0.20% in the grower diet); 2) control + intrinsically thermostable phytase A; 3) control + intrinsically thermostable phytase B; and 4) control + coated phytase C. A completely randomized design was employed. A total of 384 male broiler chicks were used, and each treatment had 6 replicates with 16 birds per replicate. The birds were reared until d 21 in floor pens with hardwood shavings. Thirty-two birds (8 birds per treatment) were randomly selected to determine heat production and NE (from 25-28 d) following a 3-d acclimatization in the respiratory chambers. Performance results at d 21 showed that supplementation with either of the 3 phytases improved body weight (P < 0.001) and feed intake (P < 0.05), and increased the relative weights of tibia ash (P < 0.05) and toe ash (P < 0.01). Phytases A and B increased the NE value of the diet (P < 0.05). It may be concluded that the negative effects imposed by calcium and available phosphorus down-specification can be compensated by phytase supplementation in general, and intrinsically thermostable phytases improve the ME and NE value. However, phytase did not reduce heat production, heat increment, or increase NE:ME in birds., (© 2015 Poultry Science Association Inc.)

The objectives of the present study were to investigate the effects of cow group on energy expenditure and utilization efficiency. Data used were collated from 32 calorimetric chamber experiments undertaken from 1992 to 2010, with 823 observations from lactating Holstein-Friesian (HF) cows and 112 observations from other groups of lactating cows including Norwegian (n=50), Jersey × HF (n=46), and Norwegian × HF (n=16) cows. The metabolizable energy (ME) requirement for maintenance (MEm) for individual cows was calculated from heat production (HP) minus energy losses from inefficiencies of ME use for lactation, energy retention, and pregnancy. The efficiency of ME use for lactation (kl) was obtained from milk energy output adjusted to zero energy balance (El(0)) divided by ME available for production. The effects of cow groups were first evaluated using Norwegian cows against HF crossbred cows (F1 hybrid, Jersey × HF and Norwegian × HF). The results indicated no significant difference between the 2 groups in terms of energy digestibility, ratio of ME intake over gross energy intake, MEm (MJ per kg of metabolic body weight, MJ/kg(0.75)), or kl. Consequently, their data were combined (categorized as non-HF cows) and used to compare with those of HF cows. Again, we detected no significant difference in energy digestibility, ratio of ME intake over gross energy intake, MEm (MJ/kg(0.75)), or kl between non-HF and HF cows. The effects were further evaluated using linear regression to examine whether any significant differences existed between HF and non-HF cows in terms of relationships between ME intake and energetic parameters. With a common constant, no significant difference was observed between the 2 groups of cows in coefficients in each set of relationships between ME intake (MJ/kg(0.75)) and MEm (MJ/kg(0.75)), El(0) (MJ/kg(0.75)), HP (MJ/kg(0.75)), MEm:ME intake, El(0):ME intake, or HP:ME intake. However, MEm values (MJ/kg(0.75)) were positively related to ME intake (MJ/kg(0.75)), irrespective of cow group. We concluded, therefore, that cow groups evaluated in the present study had no significant effects on energy expenditure or energetic efficiency. However, the maintenance energy requirement (MJ/kg(0.75)) was not constant (as adopted in the majority of energy rationing systems across the world) but increased with increasing feed intake., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Urinary energy losses in cats have to be determined in energy balance trials as well as for the calculation of the metabolizable energy (ME) content of cat food. The aim of the present study was: first, to assess whether the energy content of cat urine quantified by bomb calorimetry differs from that quantified using GE (kJ) urine = 33 kJ × g C urine + 9 kJ × g N urine and investigate whether this difference could be attributed to influences of diets. Second, to assess whether the subtraction of 3.1 kJ/g of protein intake used for estimation of metabolizable energy content of cat foods is confirmed as usable. Data from 27 energy and protein balance trials from different studies with complete sampling of urine and faeces (29 cats in part A and 35 cats in part B) were used. Gross energy, carbon and nitrogen were determined in food, faeces and urine. Gross energy values in urine tended to be higher when determined with the formula of Hoffman and Klein compared to bomb calorimetry. The average relative difference of gross energy values between the methods was 18.8%. The mean energy loss in kJ/g of protein intake resulted in 3.7 kJ/g protein intake, which was not statistically significantly different (p = 0.12) from the tested value of 3.1 kJ/g of protein intake. In conclusion, the formula of Hoffman and Klein is not appropriate for the estimation of energy in cat urine. In balance studies, it is advisable to quantify the urinary energy content by bomb calorimetry. In the second part of the study, the protein correction factor to determine ME of 3.1 kJ/g protein intake for urinary energy losses of Kienzle et al. could be confirmed., (Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.)

The effect of dietary nonphytate P (nPP) and Ca concentration on the Ca appetite in broilers was evaluated. A total of 288 one-day-old male Ross 308 broilers were fed a commercial diet for 7 d then randomly allocated to 1 of 8 dietary treatments for a 28-d study. Diets were corn-soybean meal based and formulated to be nutritionally adequate except for nPP and Ca. Two concentrations of Ca (5.0 and 10.0 g/kg) and 4 of nPP (2.5, 3.5, 4.5, and 5.5 g/kg) were used, and all birds had access to a separate Ca source (CaCO3). Bird performance, nutrient digestibility, and tibia ash were determined. Birds fed 5.0 g of Ca/kg diets consumed more (P < 0.01) of the separate Ca source than birds fed diets containing 10.0 g of Ca/kg. Increased consumption (P < 0.01) of the separate Ca source was associated with increasing nPP concentration. Bird performance was not influenced by dietary treatment. Birds fed 5.5 g of nPP/kg diets had lower (P < 0.01) digestibility of DM, CP, and energy than the other groups. Phosphorus digestibility was reduced in birds fed high Ca diets and those fed 2.5 g of nPP/kg diets (P < 0.001). Birds fed 2.5 g of nPP/kg had lower tibia ash values than those fed higher concentrations of nPP while feeding diets containing 10.0 g of Ca/kg led to higher concentrations (P < 0.05) of tibia ash than for birds fed 5.0 g of Ca/kg. This study confirms previous findings that birds are able to meet their Ca requirement when fed Ca separately from the mixed ration. Consumption of the separate Ca source responded to not only Ca concentration but also to the amount of nPP in the diet. These data suggest that dietary nPP concentration influences the Ca specific appetite of broilers, and this may indicate that birds attempt to regulate their intake of Ca relative to nPP. This may be mediated via a physiological mechanism to maintain an appropriate Ca:nPP intake., (© 2014 Poultry Science Association Inc.)

This study investigated the effect of dietary Ca to available P (AvP) ratio and phytase supplementation on bone ash, ileal phytate degradation, and nutrient digestibility in broilers fed corn-based diets. The experimental design was a 4 × 2 factorial arrangement of treatments evaluating 4 Ca:AvP ratios (1.43, 2.14, 2.86, and 3.57) and 2 levels of phytase (0 and 1,000 phytase units/kg of feed). The 4 Ca:AvP ratios were achieved by formulating all diets to a constant AvP level of 0.28% and varying Ca levels (0.4, 0.6, 0.8, and 1.0%). Each treatment was fed to 6 cages of 8 male Ross 308 broilers from 5 to 21 d. At 21 d, digesta from the terminal ileum was collected and analyzed for energy, phytate, P, Ca, and amino acids (AA) to determine digestibility. Digesta pH was measured in each segment (crop, gizzard, duodenum, and ileum) of the digestive tract. Data were analyzed by 2-way analysis of covariance. There was a significant interaction between dietary Ca:AvP ratio and phytase supplementation for weight gain (WG), feed intake (FI), and feed conversion ratio (FCR). In diets with no phytase, Ca:AvP ratio had a greater effect on WG, FI, and FCR compared with those fed diets without phytase. The orthogonal polynomial contrasts showed that the increase in dietary Ca:AvP ratio significantly decreased WG and FI in a quadratic manner, whereas FCR increased (P < 0.05) linearly with higher dietary Ca:AvP ratio. Increasing dietary Ca:AvP ratio led to a significant quadratic decrease in phytate degradation and significant linear decreases in P digestibility and bone ash. Phytase addition increased (P < 0.05) phytate degradation and improved (P < 0.05) energy, AA, and P digestibility at all levels of Ca:AvP with no interaction (P > 0.05) between the main factors. Digestibility of AA was positively correlated (P < 0.05) with the degree of phytate degradation. Increasing dietary Ca:AvP ratio significantly increased gizzard pH in a linear manner. In conclusion, phytase (1,000 phytase units/kg of feed) improved phytate, and P and AA digestibility at all Ca:AvP ratios evaluated in this study.

Samples of sorghum distillers dried grains with solubles (DDGS) were collected and analyzed to establish a nutrient database and evaluate the quality and consistency between and within 5 ethanol plants in Kansas and Texas. Each sample (n = 21) was analyzed for AA, DM, CP, crude fiber, crude fat, ash, NDF, ADF, trace minerals, and starch. Mean values (DM basis) were 0.88% Lys, 10.49% crude fat, 34.21% CP, and 4,722 kcal/kg GE. The standard deviations among sorghum DDGS plants were similar to those within plants for most nutrients. Results of these analyses were used to formulate diets for 2 nursery trials. The 2 experiments were conducted to determine the effects of adding sorghum DDGS (29.0% CP and 7.2% crude fat) to corn- or sorghum-based diets on nursery pig growth performance. In Exp. 1, 360 nursery barrows (6.8 kg and 26 d of age) were used in a 34-d study. Pigs were allotted to 1 of 8 dietary treatments with 5 pigs per pen and 9 pens per treatment. Treatments were arranged in a 2 × 4 factorial with main effects of grain source (corn vs. sorghum) and sorghum DDGS (0, 15, 30, or 45%). Diets were formulated to 1.30 and 1.25% standardized ileal digestible (SID) Lys in phases 1 and 2, respectively, but were not balanced for energy. Overall, there were no differences among pigs fed sorghum- or corn-based diets for ADG and ADFI; however, as sorghum DDGS increased from 0 to 45% of the diet, ADG decreased (linear, P < 0.01). There was a DDGS × grain source interaction (linear, P < 0.04) observed for G:F. In corn-based diets, pigs fed increasing sorghum DDGS had relatively similar G:F. However, in pigs fed sorghum-based diets, G:F was best for those fed 0% DDGS but was decreased in pigs fed 15, 30, or 45% sorghum DDGS. In Exp. 2, 180 nursery pigs (10.7 kg and 38 d of age) were used in a 21-d study with 6 pigs per pen and 5 pens per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of grain source (corn vs. sorghum) and DDGS (0 vs. 30% corn or sorghum DDGS). Diets were formulated to 1.27% SID Lys and were not balanced for energy. Overall, there were no differences in ADG among pigs fed sorghum- or corn-based diets as well as no differences among pigs fed sorghum or corn DDGS. Pigs fed diets with 30% DDGS gained less (P < 0.03) than pigs fed basal diets. These results indicate sorghum can be a suitable replacement for corn in nursery pig diets, but increasing sorghum DDGS decreased ADG.

A study was conducted to determine the standardized ileal digestibility (SID) of AA and calculate the NE value for regular-oligosaccharide, micronized full-fat soybean (R-MFFSB), low-oligosaccharide, micronized full-fat soybean (LO-MFFSB), lentil, and enzymatically hydrolyzed casein (EHC) for growing pigs. Six ileal-cannulated barrows (31.4 kg BW) were fed 6 diets in a 6 × 6 Latin square. Five diets were cornstarch based, containing either soybean meal (SBM), R-MFFSB, LO-MFFSB, or EHC as sole protein source or N free. The sixth diet contained lentil as sole protein and energy source. The SID of AA for diets was calculated using the N-free diet. Digestibility of AA in feedstuffs was determined by the direct method. Energy digestibility in SBM, R-MFFSB, and LO-MFFSB was determined by difference from the N-free diet whereas energy digestibility in lentil was determined by the direct method. On DM basis, SBM, R-MFFSB, LO-MFFSB, and lentil contained 52, 43, 43, and 27% CP, 8, 12, 14, and 16% NDF, and 1.8, 19, 21, and 1.6% ether extract, respectively. The SID of Lys for SBM was greater (P < 0.05) than that for R-MFFSB or LO-MFFSB (76 vs. 79 and 79%). The SID of other indispensable AA (except Trp) for SBM was also greater (P < 0.05) than that for R-MFFSB or LO-MFFSB. The R-MFFSB and LO-MFFSB were similar in SID of AA. The SID of Lys for lentil (81%) was lower (P < 0.05) than that for SBM with a similar trend for SID of other indispensable AA except for Met and Thr whose SID was similar to SBM. The SID of AA for EHC ranged from 98 to 112%. The SBM had a lower (P < 0.05) NE value than R-MFFSB or LO-MFFSB (2.63 vs. 2.95 and 3.00 Mcal/kg DM). Lentil and SBM were similar in NE value (2.60 vs. 2.63 Mcal/kg DM). In conclusion, R-MFFSB and LO-MFFSB were similar in energy and AA value for pigs. Lentil had lower SID of AA than SBM. However, lentil and SBM were similar in NE value; therefore, lentil can serve as alternative pulse feedstuff for pigs. The AA in EHC were mostly completely digested indicating that EHC can be fed to estimate ileal endogenous AA losses.

An experiment consisting of 2 identically designed trials was conducted to determine the nutrient composition and AMEn content of distillers dried grains with solubles (DDGS) to develop prediction equations for AMEn in broilers. Fifteen samples of DDGS ranging in ether extract (EE) from 3.15 to 13.23% (DM basis) were collected from various dry-grind ethanol plants and were subsequently fed to broiler chicks to determine AMEn content. A corn-soybean meal control diet was formulated to contain 15% dextrose, and test diets were created by mixing the control diet with 15% DDGS at the expense of dextrose. In each trial, 672 male Ross × Ross 708 chicks were housed in grower battery cages with 7 birds per cage (0.06 m(2)/bird) and received a common starter diet until 10 d of age. Each cage was randomly assigned to 1 of 16 dietary treatments, with 6 replicate pens per treatment. Experimental diets were fed over a 6-d acclimation period from 10 to 16 d of age, followed by a 48-h total excreta collection period. Gross energy (GE) and CP of the experimental diets and excreta were determined to calculate AMEn for each DDGS sample. On a DM basis, AMEn of the 15 DDGS samples ranged from 1,869 to 2,824 kcal/kg. Analyses were conducted to determine the GE, CP, EE, DM, starch, total dietary fiber (TDF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and ash content of the DDGS samples. Stepwise regression resulted in the following best-fit equation for AMEn (DM basis) based on the adjusted coefficient of determination (R(2)adj), SE, and prediction error sum of squares (PRESS): AMEn, kcal/kg = -12,282 + (2.60 × GE) + (89.75 × CP) + (125.80 × starch) - (40.67 × TDF; R(2)adj = 0.86; SE = 98.76; PRESS = 199,819; P ≤ 0.001). These results indicated that the composition of DDGS with variable EE content may be used to predict AMEn in broiler chicks.

Two experiments were conducted to determine the DE and ME content of corn distillers dried grains with solubles (corn-DDGS) containing variable ether extract (EE) concentrations and to develop DE and ME prediction equations based on chemical composition. Ether extract content of corn-DDGS ranged from 4.88 to 10.88% (DM basis) among 4 corn-DDGS samples in Exp. 1 and from 8.56 to 13.23% (DM basis) among 11 corn-DDGS samples in Exp. 2. The difference in concentration of total dietary fiber (TDF) and NDF among the 4 corn-DDGS sources was 2.25 and 3.40 percentage units, respectively, in Exp. 1 but was greater among the 11 corn-DDGS sources evaluated in Exp. 2, where they differed by 6.46 and 15.18 percentage units, respectively. The range in CP and ash were from 28.97 to 31.19% and 5.37 to 6.14%, respectively, in Exp. 1 and from 27.69 to 32.93% and 4.32 to 5.31%, respectively, in Exp. 2. Gross energy content among corn-DDGS samples varied from 4,780 to 5,113 kcal/kg DM in Exp. 1 and from 4,897 to 5,167 kcal/kg DM in Exp. 2. In Exp. 1, the range in DE content was from 3,500 to 3,870 kcal/kg DM and ME content varied from 3,266 to 3,696 kcal/kg DM. There were no differences in ME:DE content among the 4 corn-DDGS sources in Exp. 1, but ME:GE content differed (P = 0.04) among sources (66.82 to 74.56%). In Exp. 2, the range in DE content among the 11 corn-DDGS sources was from 3,474 to 3,807 kcal/kg DM and ME content varied from 3,277 to 3,603 kcal/kg DM. However, there were no differences in DE:GE, ME:DE, or ME:GE among sources in Exp. 2. In Exp. 1, no ingredient physical or chemical measurement [bulk density (BD), particle size, GE, CP, starch, TDF, NDF, ADF, hemicellulose, EE, or ash)] was statistically significant at P ≤ 0.15 to predict DE or ME content in corn-DDGS. In Exp. 2, the best fit DE equation was DE (kcal/kg DM) = 1,601 - (54.48 × % TDF) + (0.69 × % GE) + (731.5 × BD) [R(2) = 0.91, SE = 41.25]. The best fit ME equation was ME (kcal/kg DM) = 4,558 + (52.26 × % EE) - (50.08 × % TDF) [R(2) = 0.85, SE = 48.74]. Apparent total tract digestibility of several nutritional components such as ADF, EE, and N were quite variable among corn-DDGS sources in both experiments. These results indicate that although EE may be a good predictor of GE content in corn-DDGS, it is not a primary factor for predicting DE or ME content. Measures of dietary fiber, such as ADF or TDF, are more important than EE in determining the DE or ME content of corn-DDGS for growing pigs.

The aim of this study was to determine if a mixed microbial community from the bovine rumen would respond to excess carbohydrate by accumulating reserve carbohydrate, energy spilling (dissipating excess ATP energy as heat), or both. Mixed microbes from the rumen were washed with N-free buffer and dosed with glucose. Total heat production was measured by calorimetry. Energy spilling was calculated as heat production not accounted by (i) endogenous metabolism (heat production before dosing glucose) and (ii) synthesis of reserve carbohydrate (heat from synthesis itself and reactions yielding ATP for it). For cells dosed with 5 mM glucose, synthesis of reserve carbohydrate and endogenous metabolism accounted for nearly all heat production (93.7%); no spilling was detected (P = 0.226). For cells dosed with 20 mM glucose, energy spilling was not detected immediately after dosing, but it became significant (P < 0.05) by approximately 30 min after dosing with glucose. Energy spilling accounted for as much as 38.7% of heat production in one incubation. Nearly all energy (97.9%) and carbon (99.9%) in glucose were recovered in reserve carbohydrate, fermentation acids, CO2, CH4, and heat. This full recovery indicates that products were measured completely and that spilling was not a methodological artifact. These results should aid future research aiming to mechanistically account for variation in energetic efficiency of mixed microbial communities.

The aim of this study was to assess the role of soluble non-starch polysaccharide (guar gum) on white sea bream Diplodus sargus, glucose and lipid metabolism. A control diet was formulated to contain 40 % crude protein, 14 % crude lipids and 35 % pregelatinized maize starch, and three other diets were formulated similar to the control diet except for guar gum, which was included at 4 % (diet GG4), 8 % (diet GG8) or 12 % (diet GG12). Diets were fed to the fish for 9 weeks on a pair-feeding scheme. Guar gum had no effect on growth performance, feed efficiency, glycaemia, cholesterolaemia and plasma triacylglyceride levels. Hepatic glucokinase and pyruvate kinase activities, liver glycogen content and liver insulin-like growth factor-I gene expression were not affected by dietary guar gum, while fructose-1,6-bisphosphatase activity was lower in fish fed guar gum-supplemented diets. Hepatic glucose-6-phosphate dehydrogenase activity was higher in fish fed diets GG4 and GG8 than in the control group. Overall, data suggest that in contrast to mammals guar gum had no effect on white sea bream glucose utilization and in lowering plasma cholesterol and triacylglyceride levels. However, it seems to contribute to lower endogenous glucose production.

To ensure broiler welfare during winter transport, it is necessary to manage heat and moisture accumulation within the transport vehicles. Hence, it is necessary to determine heat production (HP) and moisture production (MP) rates under representative conditions. An environmental chamber containing a standard transport drawer was used. Cold air was drawn from outside the building, warmed to the desired temperature, and passed through the drawer at 0.35 m(3)/s. Broilers were fasted for 7 h, placed into the drawer, and exposed to test conditions within the chamber for 3 h. Air temperature and RH were measured upstream and downstream of the insulated bird compartment at 1-min intervals. Differences in the paired temperature and RH values were used to calculate sensible HP and MP for each 1 min of confinement. Effects of temperatures between -8 and -18°C and a control (+20°C) were measured for birds in 2 conditions. In condition A, there were 15 birds/drawer. Birds were 32 to 33 d old and weighed 1.8 kg. Packing density was approximately 27 kg/drawer (31 kg/m(2)). In condition B, there were 19 or 22 birds/drawer. The drawers with 19 birds contained birds that were 39 to 40 d old that weighed 2.68 kg. In the drawers with 22 birds, the birds were 35 to 36 d old and weighed 2.29 kg. In either case, the packing density was approximately 50 kg/drawer (59 kg/m(2)). Thus, the birds in condition B were bigger, more numerous, and more tightly packed than the birds in condition A. Drawers were balanced for sex. At +20°C, HP and MP rates were similar to other published values. However, for both conditions, HP and MP rates increased with decreasing exposure temperatures. In condition A, HP was 6.08 ± 0.43 W/kg and MP was 4.46 g/h per kg at 20°C compared with 87.5 ± 10.3 W/kg and 22.08 ± 5.05 g/h per kg at -15°C. In condition B, HP was 8.12 ± 1.24 W/kg and MP was 5.53 ± 1.68 g/h per kg at 20°C compared with 45.92 ± 1.95 W/kg and 12.33 ± 0.22 g/h per kg at -18°C.

The energy density (ED) of nine species of sub-Antarctic fishes was estimated by calorimetry. The fish, seven notothenioids, one atherinopsid and one galaxiid, represents some of the more abundant species in the ichthyofauna of the Beagle Channel. Principal-components analysis (PCA) of the ED of the different organs/tissues indicated that PC(1) and PC(2) accounted for 87% of the variability. Separation along PC(1) corresponded to differences in muscle and liver energy densities whereas separation along PC(2) corresponded to differences in the ED of the gonads. Differences between species were significant except for P. sima. Inclusion of the gonadosomatic index (GSI) as an explanatory variable enabled us to establish the existence of energy transfer from muscle and liver to the gonads in ripe P. tessellata females. Total ED values varied between 4.21 and 6.26 kJ g(-1), the pelagic Odontesthes sp. being the species with the highest ED. A significant relationship between ED and muscle dry weight (DW(M)) was found for all the species except P. tessellata. These data are the first direct estimates of ED of fishes from the Beagle Channel.

Shea nut meal is obtained after fat extraction from shea nuts produced in West Africa. Two experiments compared the ME of different shea nut meal samples. The objective of the first experiment was to estimate the TME(n) of 2 expeller shea nut meal samples and a single nonindustrial shea nut meal sample using a precision-fed broiler assay. The second objective was to compare the nutrient composition of 6 collected shea nut meal samples (i.e., 4 expeller, 2 nonindustrial) as well as 2 defatted samples (1 expeller, 1 nonindustrial) and to examine the differences in AME between the samples. The 8 shea nut meal samples were fed at 3 dietary levels (0, 2, 4%) in a nutritionally complete basal diet to 180 Ross male broiler chicks (12 to 20 d) in an AME assay. The mean TME(n) (3,577 kcal/kg of DM) of expeller samples was higher (P<0.001) than TME(n) (3,017 kcal/kg of DM) of the nonindustrial sample. The dietary level of shea nut meal had a significant (P<0.01) effect on AME with the 4% level tending to give a lower AME than the 0 or 2% levels. However, increasing levels of defatted shea nut meals from 2 to 4% had no effect on AME of the diets. It was concluded that the available energy concentrations in the shea nut meal samples were low relative to their nutrient compositions and variable due to the content and nature of the residual fat. The variation observed among samples indicates that industrial expeller shea nut meal samples are preferable to nonindustrial meals for use in poultry rations. The nutritional quality of shea nut meal still needs improvement to allow it to be a valuable feed ingredient.

This study showed that in vitro survival of Salmonella typhimurium, after exposure to haemocytes of Mytilus edulis, was significantly affected by the lipopolysaccharides (LPS) structures expressed on the cell surface of the bacteria. Survival seemed to be affected by the surrounding temperature as well. Mussel haemocytes were in vitro exposed to mutants of S. typhimurium, expressing differences in O -antigen polysaccharide chains and core sugars of LPS on their cell surface. Surviving cells of the mutants were determined after incubation with the haemocytes at different temperatures, using a colorimetric assay. In addition, a complementary study on clearance of these mutants, inoculated into the adductor muscle of mussels, was performed at 6 and 20 degrees C. It was concluded that the survival index (SI%) measured in vitro for the mutant with complete LPS was significantly lower at 6 degrees C (c.15%) compared to that at 14 and 20 degrees C (c.70%). SI% for the other mutants was c.35-45% and was not affected by temperature. The in vivo study at 20 degrees C showed that during the first 24h, the clearance rate for the mutants with complete LPS was significantly higher than for the others. Thereafter all mutants, with exception for the most deficient, started to increase in numbers and caused death to the mussels. At 6 degrees C the mutants were slowly reduced and after 17 days, viable cells of the mutant with complete LPS were still detectable in the haemolymph. The study indicated that the mussel haemocytes responded in relation to the LPS of the mutants. However, more intact LPS also seemed to protect the bacteria from being killed. The higher temperatures favoured the growth of the mutants that managed to resist the haemocyte defence. Cell surface properties and temperature seem to affect the survival of bacteria in mussels, which consequently can affect risk assessments in regard to public health.

Eulamprus tympanum is a high-altitude viviparous lizard that was probably used to help define a Type I chorioallantoic placenta. In this article, we (1) describe the net transport of nutrients across the placenta of E. tympanum, and (2) compare placental uptake in E. tympanum with a previous study of Eulamprus quoyii, which occurs in warmer environments, to assess the potential importance of thermal regime on placentotrophy. Freshly ovulated eggs are 387.3+/-19.7 mg. There is a significant net uptake of water and a net loss of dry matter during development, so the dry neonate is only 84% the size of the dry egg. There is no significant change in the total ash or nitrogen in eggs during embryonic development, with the entire loss of dry matter being lipid. Almost the entire loss of lipid occurs in the triacylglycerol fraction, with no net change in phospholipids. A net increase in total cholesterol suggests that cholesterol is synthesised by the developing embryo. The lipid profile of eggs of E. tympanum reflects that of other species with simple placentae in having a relatively high proportion of triacylglycerol and little cholesterol. The fatty acid composition of eggs reflects that expected in the diet of E. tympanum. There is a preservation and some synthesis of arachidonic (20:4n-6) and docosahexaenoic (22:6n-3) acids in the phospholipid fraction during embryonic development. Despite there being no net uptake of ash, there is a net increase in calcium, potassium, sodium, and magnesium in the neonate compared with the egg. We conclude that E. tympanum, like E. quoyii, is predominantly lecithotrophic with little, if any, uptake of organic molecules but with significant uptake of some inorganic ions and water. In addition, there is no difference in placentotrophy correlated with differences in the environments inhabited by each species.

1. Two experiments were conducted to determine the effects of tannins on nutrient utilisation in the White Pekin duck. 2. Experiment 1 was a rapid nutrient balance assay to determine the nitrogen (N) retention and metabolisable energy (ME) of maize, low-tannin sorghum (P-954063) (Sorghum bicolor (L). Moench) and high-tannin sorghum (IS-4225) cultivars for ducks. The assay lasted 120 h, with an initial 24 h food-deprivation period, a 48 h excreta collection period for endogenous losses and a 48 h excreta collection period for ingredient losses. The true metabolisable energy (TMEn) content was lower (P<0.05) in the high-tannin sorghum cultivar (13.85 MJ/kg) than the maize (14.94 MJ/kg) and the low-tannin sorghum cultivar (14.39 MJ/kg). True N retention was lower (P<0.05) for the high-tannin sorghum (0.24 g) than for maize (1.33 g) and low-tannin sorghum (1.1 g). 3. In experiment 2, the brush-border membrane vesicles technique was used to determine whether tannic acid caused inhibition of L-threonine transport across duck intestinal brush-border membrane. The brush-border membrane vesicles were mixed with tannic acid solutions (pH 7.4) to give gradient tannic acid concentrations of 0, 0.05, 0.10, 0.25, 0.50, 1.00 and 2.50%. As a fraction of the control (no tannic acid), the maximal inhibition of L-threonine transport (Imax) under the sodium-gradient condition was 77.10% (P<0.05). Under the sodium-free condition, the maximal inhibition of L-threonine transport (Imax) was 45.15% (P<0.05). 4. These results demonstrated that nutrient utilisation in the White Pekin duck was lower from the high-tannin sorghum cultivar than from the low-tannin sorghum cultivar. The results also suggested that the antinutritive effects of tannins in foodstuffs are due partly to their inhibitory action on intestinal brush-border bound amino acid transporter proteins.

1. The objective of this work was to explore the possibilities of modelling the static and dynamic responses of total heat production of broiler chickens to step changes in temperature and light intensity (light-dark alterations) using compact dynamic model structures. 2. Seventy-seven experiments were performed in an open-circuit respiration chamber to measure the dynamic response of heat production to step variations in temperature and light (on/off). The animal responses were modelled using transfer function model structures. 3. It was demonstrated that the complex process of the dynamic response of heat production of broiler chickens to step changes in air temperature and light-dark alterations can be modelled assuming 1st order dynamics. The coefficient of determination between measured and simulated heat production was on average 0.83 for responses to air temperature and 0.93 for responses to light-dark alterations.

1. The yields of true metabolisable energy (TME) and net energy (NE) from chaya leaf meal and wheatfeed were mcasured in tube-fed cockerels. 2. TME, 5.76 MJ/kg, from chava leaf meal was lower than from wheatfeed, 8.39 MJ/kg. The total heat increment attributable to the feeding of chaya leaf meal was 1-7 times greater than that of wheatfeed. 3. The net efficiency of utilisation of ME (k) from chaya leaf meal was 0.64, while that from wheatfeed was 0.86. The role of different chemical composition, especially the high fibre content of the materials, is discussed. 4. The metabolisable energy and net energy values derived from chava leaf meal represented 0.34 and 0.23 respectively of its gross energy content. The combination of lower TME and lower net efficiency of utilisation led to chaya having a NE value, 3.86 MJ/kg, which was only 0.53 that of wheatfeed.

1. The apparent digestibility coefficients (ADC) of a diet consisting of a concentrate and of alfalfa grass in a 4:1 ratio were measured in 6, 12-and 18-week-old ostriches. 2. These coefficients were measured in 4 animals eating ad libitum using both a total collection method, and internal marker methods with acid detergent lignin (ADL) and with acid insoluble ash (AIA). 3. The ADC of dry matter, organic matter, crude protein, ether extract and energy were not influenced by the age of the ostriches. The ADC of structural carbohydrates, however, were significantly higher (P<0.01) in the 12-and 18-week-old animals. 4. The results obtained by the total collection and ADL methods were similar. The AIA method, however, overestimated the values due to the very high marker recovery rate (128.0%).

Anhydrobiosis is considered to be an important means of achieving storage stability of entomopathogenic nematodes that are used in biological control. This study explored the effects of anhydrobiosis on longevity and infectivity of infective juveniles (IJs) of three species of entomopathogenic nematodes Steinernema carpocapsae, Steinernema feltiae, and Steinernema riobrave at 5 and 25 degrees C. Anhydrobiosis was induced in water-dispersible granules (WG) at 0.966-0.971 water activity and 25 degrees C following a 7-day preconditioning of IJs at 5 degrees C in tap water. Survival and infectivity of the desiccated (anhydrobiotic) IJs was compared with non-desiccated IJs stored in water for different periods. Anhydrobiosis increased longevity of S. carpocapsae IJs by 3 months and of S. riobrave by 1 month in WG at 25 degrees C as compared with IJs stored in water. However, desiccation decreased S. feltiae longevity at 25 degrees C and of all three species at 5 degrees C. These results demonstrate a shelf-life of 5 months for S. carpocapsae at 25 degrees C and 9 months at 5 degrees C in WG with over 90% IJ survival. For S. feltiae, over 90% survival occurred only for 2 months at 25 degrees C and 5 months at 5 degrees C in WG. Steinernema riobrave had over 90% survival only for 1 month at 25 degrees C and the survival dropped below 85% within 1 month at 5 degrees C. Induction of anhydrobiosis in WG resulted in 85, 79 and 76% reduction in oxygen consumption by S. carpocapsae, S. feltiae, and S. riobrave IJs, respectively. Differences in IJ longevity among three species in water at 25 degrees C were related both to the initial lipid content and the rate of lipid utilisation, but not at 5 degrees C. The one-on-one infection bioassays indicated that desiccation had no negative effect on the infectivity of any of the nematode species suggesting no harmful effect on the IJs and/or their symbiotic bacteria. The species differences in IJ longevity and desiccation survival at different temperatures are discussed in relation to their foraging strategy and temperature adaptation.

1. The effect of diet form (mash, cold-pelleted, steam-conditioned/pelleted, wet mash, whole wheat with balancer pellet, restricted pellet) and enzyme inclusion (Avizyme 1300, absent, present) was studied in 2 trials using individually caged, male broilers from 14 to 42 d. Bird performance, viscosity of ileal contents and diet metabolisability (AME) were measured. 2. The performance of mash-fed birds was significantly poorer than for the other treatments in relation to dry matter intake, liveweight gain and gain:food. This was not due to reduced diet AME content. 3. There was no significant effect of heat treatment on any of the variables measured, although viscosity of ileal contents was increased by 30% as compared to the cold-pelleted diet. 4. Gain:food was improved with wet-mash feeding in comparison to the dry mash treatment but it was concluded that this was not due to any intrinsic improvement in diet quality, but rather to voluntary food restriction on introduction of the wet food. 5. Whole wheat feeding improved gain:food and diet AME content by 3% as compared to the complete diets and caused approximately a 50% increase in gizzard weight as compared with the pelleted diets. 6. Food enzyme inclusion did not improve performance although a significant improvement in diet AME content was observed with enzyme inclusion in trial 1.

Objective: To compare effects of low and high intensity warm-up exercise on oxygen consumption (VO2) and carbon dioxide production (VCO2) in horses., Animals: 6 moderately conditioned adult Standard-breds., Procedures: Horses ran for 2 minutes at 115% of maximum oxygen consumption (VO2max), 5 minutes after each of the following periods: no warm-up (NoWU); 10 minutes at 50% of VO2max (LoWU); or 7 minutes at 50% VO2max followed by 45-second intervals at 80, 90, and 100% VO2max (HiWU). Oxygen consumption and VCO2 were measured during exercise, and kinetics of VO2 and VCO2 were calculated. Accumulated O2 deficit was also calculated., Results: For both warm-up trials, the time constant for the rapid exponential increase in VO2 was 30% lower than for NoWU. Similarly, the rate of increase in VCO2 was 23% faster in LoWU and HiWU than in NoWU. Peak values for VO2 achieved during the high-speed test were not significantly different among trials (LoWU, 150.2 +/- 3.2 ml/kg/min; HiWU, 151.2 +/- 4.2 ml/kg/min; NoWU, 145.1 +/- 4.1 ml/kg/min). However, accumulated O2 deficit (ml of O2 equivalents/kg) was significantly lower during LoWU (65.3 +/- 5.1) and HiWU (63.4 +/- 3.9) than during NoWU (82.1 +/- 7.3)., Conclusions and Clinical Relevance: Both the low- and high-intensity warm-up, completed 5 minutes before the start of high-intensity exercise, accelerated the kinetics of VO2 and VCO2 and decreased accumulated O2 deficit during 2 minutes of intense exertion in horses that were moderately conditioned.

1. Apparent MEn and oil digestibility of hulled sunflower seed (SFS) and the products derived from the oil extraction process: press extracted SFS (PESFS), sunflower seed meal (SFSM), and press and solvent oils (PO and SO) were determined with 198 cockerels. Recombined products (mix of meal and oil) were also evaluated to study the effect of the 2 consecutive oil extraction steps. Each foodstuff was included in a basal diet, according to the proportions resulting from processing, at 100, 200, and 300 g SFS/kg. 2. Dietary energy value and digestible fat content were linearly related to rate of inclusion of test ingredients. Extrapolation values for AMEn (MJ/kg DM) were: SFS, 16.20; PESFS, 9.46; SFSM, 7.62. A decreasing quadratic trend was also found in the AMEn of PESFS, with interpolation values ranging from 11.77 to 9.33 MJ/kg DM between 70 and 210 g/kg DM of inclusion. No differences were observed between PO and SO. The AMEn of of sunflower oil, calculated from its digestibility, was 33.70 MJ/kg DM. 3. The oil extraction process affected the nutritional value of sunflower products. Recombined materials showed greater values than original foodstuffs: R-SFS, 17.47; R-PESFS, 11.49 MJ/kg DM. The increase in oil digestibility (from 0.814 to 0.862 g/kg DM in SFS; from 0.778 to 0.892 in PESFS) accounted for most of the increase observed in AMEn values. 4. As the form in which oil is incorporated in diets (released or within SFS or PESFS) affects the utilisation of sunflower products, their nutritional value is less than maximal and should not be calculated from their ingredients. Solvent oil seems to be the less available fraction of sunflower oil within SFS as the effect of the 2nd extraction proved to be greater than that of the previous press extraction.

1. Two experiments were performed to evaluate the effect of dietary fat on performance and fat and protein accretion in broiler chickens according to the degree of saturation. 2. The first experiment was designed to test 2 sources of dietary fat and 3 levels of dietary energy using a factorial (2x3) experimental design. The foods were formulated to maintain a constant ratio of energy to protein (and other nutrients). There were no significant differences in weight gain, intake, final body weight or food to gain ratio between broilers fed on diets differing solely in the degree of fat saturation. Broilers fed on diets containing animal fat showed higher whole-body fat retention (P=0.02) and lower protein accretion (P=0.03) than those fed on diets containing vegetable oils. 3. In the second experiment, only 1 concentration of fat (tallow, lard or sunflower oil) was incorporated into the experimental diets, providing different energy to protein ratios. The carcase protein content was not affected by dietary fat source, while total fat accretion (P=0.01) and energy retention (P=0.14) were highest in broilers fed on a diet containing tallow. 4. The findings suggest that the degree of saturation of dietary fats affects their metabolic use and fat accumulation in broiler chickens.

Activity of supplemental enzymes in a barley-soybean-maize based diet at 60, 75 and 90 degrees C pelleting temperatures was studied using feed viscosity, in-vitro enzyme activity and broiler performance data. High pelleting temperatures increased feed viscosity but supplemented enzymes reduced the viscosity at all three temperatures levels by 11, 14 and 17%, respectively. Water intake and losses in excreta of birds were found to be affected by feed viscosity. Activity of cellulase enzyme, measured using the radial diffusion method, was unaffected at 60 and 75 degrees C, but reduced by 73% in feed processed at 90 degrees C. Enzymes increased the weight gain of broilers by 11.1% at 90 degrees C, but no effect could be seen at low pelleting temperatures possibly due to high dietary protein and energy contents. Feed intake was unaffected by enzymes. Birds consumed 6% more feed and grew 9% faster when the pelleting temperature was increased from 60 to 75 degrees C. Reduced feed intake and daily weight gain observed at 90 degrees C could be fully compensated by the enzyme supplementation. High pelleting temperature reduced energy metabolizability (3.2%) and nitrogen utilization (4%) but enzyme almost compensated them (by 3.3% and 2.6%, respectively). No interaction could be detected between the pelleting temperatures and enzymes. It is concluded that pelleting temperatures as high as 90 degrees C drastically reduce cellulase activity, energy and nitrogen utilization thus lowering broiler performance. Either the remaining activity of cellulase or other thermostable enzymes can prevent the losses.

Raw yolk of 1-d-old eggs was either subjected to linear electron beam irradiation at approximately 2.5 kGy dosage or not processed. Both irradiated and nonprocessed egg yolk samples were stored at -15 C after irradiation. Testing was conducted on 0, 1, 7, 15, 30, and 60 d of storage. Development of storage modulus (G') was delayed in irradiated samples after 7 d, which suggests that less structure was developed in irradiated egg yolk than in nonprocessed egg yolk during storage. Irradiated samples retained more soluble protein within the first 7 d and showed slightly improved emulsion capacity over that from nonprocessed samples. However, irradiated egg yolk was less bright than nonprocessed samples. No differences were observed in SDS-PAGE patterns of soluble proteins and delipidized low density lipoprotein (LDL). The LDL isolated from irradiated liquid egg yolk showed no difference in N-terminal amino acids compared to that of nonprocessed egg yolk, indicating no detectable cleavage of LDL. However, the denaturation temperature of irradiated samples at Day 0 shifted about 1 C lower than that of the nonprocessed sample. Results indicated that electron beam irradiation did not cause significant physical, chemical or functional changes of egg yolk, or cleavage of egg yolk protein. Therefore, electron beam irradiation could serve as a preservation method for liquid egg yolk.

Two trials were conducted to determine the effects of steam-flaked sorghum grain bulk density on animal performance, cost of production, and propensity to induce ruminal acidosis in feedlot steers. In Trial 1, 336 yearling steers (343 kg; SEM = .346) were fed diets for 125 d that contained sorghum grain (82.5%, DM basis) flaked to .283 (L), .322 (M), or .361 (H) kg/L (i.e., 22, 25, and 28 lb/bu). Steers fed L consumed 3.2% less DM than those fed H (linear, P < .05), resulting in 6.9% lower ADG (linear, P = .02) and 3.6% lower gain efficiency (linear, P < .15). Sorghum grain flaked to M and L had 16 and 46% greater starch gelatinization than H (measured using differential scanning calorimetry; linear, P = .002). Dressing percentage increased linearly (P < .05) with increasing flake density, but no other carcass measurements were affected by treatment. Increasing flake density increased mill production rate linearly (P < .01), resulting in the lowest energy usage per unit of flaked grain for the H treatment. Trial 2 was an acidosis challenge study that incorporated six ruminally cannulated steers (422 kg; SEM = .129) into a replicated 3 x 3 Latin square experiment. Reducing flake density resulted in linear reductions in ruminal pH following intake challenge at 3, 33, and 36 h after the d-12 challenge (P < .05). There was a linear increase in the area between the pH vs time curve and a line at pH 5.5 (P < .01) and 5.0 (P = .09) with decreasing flake density (28.0, 25.2, and 18.2 pH-hours below 5.5 and 9.6, 7.3, and 3.9 pH-hours below 5.0 for L, M, and H, respectively). Cattle consuming L also tended to have higher VFA concentrations (mM) at 36 h after challenge (P = .12). There was no significant treatment effect on ruminal lactate. Flaking sorghum grain to .283 and .322 kg/L resulted in reduced intake and poorer animal performance compared with .361 kg/L (58.7% starch gelatinization), higher susceptibility to subacute acidosis, and higher costs of production.

The objectives of this study were 1) to determine the effects of supplemental ascorbic acid (AA) on the energy conversion of broiler chicks maintained at thermoneutral and potential heat stress temperatures using indirect convective calorimetry; and 2) to determine whether changes in energy conversion are reflected in changes in lipid metabolism. In Experiment 1, 120 2-d-old cockerels, housed in two identical environmental chambers, were maintained under constant light (2.0 +/- 0.2 fc) and recommended thermal conditions (29.6 +/- 0.8 C; 33.4 +/- 8.0% RH) and consumed water and feed ad libitum. Beginning on Day 8 posthatch, one-half of the birds inside each chamber were randomly assigned and received feed supplemented with AA. Beginning on Day 9 posthatch, the temperature inside one chamber was increased to 34 C whereas the other chamber remained thermoneutral. This design resulted in four treatments: 1) thermoneutral (TN: 27.7 +/- 0.8 C; 40.9 +/- 9.4% RH) and 0 mg AA/kg feed (ppm); 2) TN and 150 ppm AA; 3) heat stress (H: 33.8 +/- 0.5 C; 43.3 +/- 7.4% RH) and 0 ppm AA; or 4) H and 150 ppm AA. Also beginning on Day 9 posthatch, birds were randomly assigned to one of three identical, indirect convective calorimeters designed to accommodate TN or H. Oxygen consumption, carbon dioxide production, respiratory quotient, and heat production were evaluated daily for 8 h, through Day 17 posthatch. Following calorimetric measurement, birds were returned to their respective caging unit/chamber for the remainder of the study. Weight gain, feed intake, and gain: feed were also measured over the 9-d study. Heat exposure depressed (P < 0.05) weight gain, feed intake, and gain:feed. Ascorbic acid increased (P < 0.10) weight gain. Oxygen consumption and carbon dioxide and heat production per kilogram0.75 decreased (P < 0.05) with age with no change in the respiratory quotient. Heat exposure lowered (P < 0.001) the respiratory quotient. A temperature by AA interaction was detected in which heat-exposed birds expressed lower (P < 0.10) respiratory quotients when consuming the AA-supplemented diet. In Experiment 2, 18 2-d-old cockerels, housed in an environmental chamber, were maintained under constant light and recommended thermal conditions (29.3 +/- 0.4 C; 41.4 +/- 3.3% RH) and consumed water and feed ad libitum. On Day 9 posthatch, birds were deprived of feed for 24 h with ad libitum access to water supplemented with either 0 or 400 mg AA/L. Blood samples were obtained from each bird before and after feed withdrawal and supplementation. Supplemented birds exhibited elevated (P < 0.01) plasma AA, levels that were not affected by feed deprivation. Feed deprivation increased (P < 0.0001) plasma beta-hydroxybutyrate with no effect of AA, and decreased (P < 0.05) plasma triglycerides in the unsupplemented birds. A feed withdrawal by AA interaction was detected in which plasma triglycerides remained elevated in birds supplemented with AA. These data suggest that supplemental AA influences body energy stores that are used for energy purposes during periods of reduced energy intake.

Divergent selection for heat production/loss (kcal.kg-.75.d-1), measured in 9- to 11-wk-old male mice, was conducted for 15 generations. Heat loss was measured for 15 h on individual animals placed overnight in direct, gradient-layer calorimeters. Selection for high (MH) and low (ML) heat loss and unselected control (MC) occurred in each of three replicates for a total of nine unique lines. Repeatability of the heat loss measurement was .45 and the CV was 10.5%. Cumulative realized selection differentials, averaged for the three replicates, were 145.1 and -105.0 (kcal.kg-.75.d-1) and ranged from 136.9 to 149.2 and -17.1 to -101.3 for MH and ML selection, respectively. Cumulative standardized realized selection differentials, averaged for the three replicates, were 10.06 and -9.51 for MH and ML selection, respectively. Direct responses (kcal.kg-.75.d-1) in heat loss after 15 generations were 44.2 for MH and -27.4 for ML as deviations from MC. Asymmetry of response was evident (P = .03) by Generation 10. Realized heritability was .28 +/- .01 based on divergence of MH and ML selection. For selection for higher and lower heat loss, realized heritabilities were .31 +/- .01 and .26 +/- .01, respectively.

Irradiation sensitivity of five Salmonella enteritidis isolates inoculated either on the surface or inside of whole shell eggs were determined. The shell eggs were irradiated at doses of 0, 0.5, 1.0, and 1.5 kGy. A minimal dose of 0.5 kGy was sufficient to eliminate all the isolates from the surface of whole eggs; however, the same isolates were more resistant to irradiation when present inside the eggs. The ATCC 13076 isolate was significantly more sensitive to irradiation, with a D value of 0.32 kGy, than the other four isolates from animal origin. Irradiation D values of the latter ranged from 0.39 to 0.41 kGy. Liquid whole eggs were also inoculated (2.4 x 10(6) cells per milliliter) with two S. enteritidis isolates and were heat-treated at 50 C for 0, 20, 40, or 60 min followed by irradiation at 0, 0.25, 0.5, 0.75, or 1.0 kGy. The results indicate that mild heating prior to irradiation was ineffective in reducing the irradiation D values. However, on the basis of the D values obtained, an irradiation dose of 1.5 kGy should be sufficient to reduce Salmonella counts by approximately 4 log10 in both whole shell and liquid eggs. Results also indicate that color and thermal characteristics of the whole or liquid eggs were unaffected by a 1.5-kGy dose of irradiation.

The present work deals with the construction and function of a confinement chamber for small ruminants intended for use in short energy metabolism studies. CH4, CO2 and O2 are analysed according to physical principles. Several calibration tests of the whole system were carried out with satisfactory results. A close agreement has been observed when comparing the values of day-to-day variation heat production obtained by confinement and open-circuit calorimetry.

1. An open-circuit, automated, multi-calorimeter system for studies on the energy metabolism of the fowl is described. 2. Discontinuous observations of 10-min duration once each hour for 22 h gave good agreement with continuous observations throughout 22 h. 3. It is essential to train each hen before a series of calorimeter experiments. 4. A distinctive pattern of light-entrained, diurnal variation of metabolic rate has been observed in starving and fed birds of two laying strains.