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ABSTRACT: Maintenance of calcium and phosphorus homeostasis in laying hens is crucial for preservation of skeletal integrity and eggshell quality, though physiological regulation of these systems is incompletely defined. To investigate changes in mineral and vitamin D3 homeostasis during the 24-h egg formation cycle, 32-wk-old commercial laying hens were sampled at 1, 3, 4, 6, 7, 8, 12, 15, 18, 21, 23, and 24 h post-oviposition (HPOP; n ≥ 4). Ovum location and egg calcification stage were recorded, and blood chemistry, plasma vitamin D3 metabolites, circulating parathyroid hormone (PTH), and expression of genes mediating uptake and utilization of calcium and phosphorus were evaluated. Elevated levels of renal 25-hydroxylase from 12 to 23 HPOP suggest this tissue might play a role in vitamin D3 25-hydroxylation during eggshell calcification. In shell gland, retinoid-x-receptor gamma upregulation between 6 and 8 HPOP followed by subsequently increased vitamin D receptor indicate that vitamin D3 signaling is important for eggshell calcification. Increased expression of PTH, calcitonin, and fibroblast growth factor 23 (FGF23) receptors in the shell gland between 18 and 24 HPOP suggest elevated sensitivity to these hormones toward the end of eggshell calcification. Shell gland sodium-calcium exchanger 1 was upregulated between 4 and 7 HPOP and plasma membrane calcium ATPase 1 increased throughout eggshell calcification, suggesting the primary calcium transporter may differ according to eggshell calcification stage. Expression in shell gland further indicated that bicarbonate synthesis precedes transport, where genes peaked at 6 to 7 and 12 to 18 HPOP, respectively. Inorganic phosphorus transporter 1 (PiT-1) expression peaked in kidney between 12 and 15 HPOP, likely to excrete excess circulating phosphorus, and in shell gland between 18 and 21 HPOP. Upregulation of FGF23 receptors and PiT-1 during late eggshell calcification suggest shell gland phosphorus uptake is important at this time. Together, these findings identified potentially novel hormonal pathways involved in calcium and phosphorus homeostasis along with associated circadian patterns in gene expression that can be used to devise strategies aimed at improving eggshell and skeletal strength in laying hens.

ABSTRACT: Vitamin D3 is hydroxylated by cytochrome P450 (CYP) before exerting biological effects. The chicken CYP involved in vitamin D3 25-hydroxylation has yet to be cloned, and little is known about its functional characteristics, tissue distribution, and cellular expression. We identified a novel, full-length CYP27A1 gene cloned from chicken hepatocyte cDNA that encodes a putative protein of 518 amino acids. Swiss modeling revealed that chicken CYP27A1 has a classic open-fold form. Multisequence homology alignment determined that CYP27A1 contains conserved motifs for substrate recognition and binding. Quantitative real-time PCR analysis in 2-mo-old Partridge Shank broilers demonstrated that CYP27A1 mRNA levels were highest in the liver, followed by the thigh muscles, the breast muscles, and kidneys. The transcripts of CYP27A1 in breast muscles were significantly higher in males than in females. A subcellular localization analysis demonstrated that CYP27A1 was mainly expressed in the mitochondria. In vitro enzyme assays suggested that recombinant CYP27A1 hydroxylates vitamin D3 at the C-25 position to form 25-hydroxyvitamin D3 (25(OH)D3). The Km and Vmax values for CYP27A1-dependent vitamin D3 25-hydroxylation were estimated to be 4.929 μM and 0.389 mol min−1 mg−1 protein, respectively. In summary, these results suggest that CYP27A1 encodes a mitochondrial CYP that plays an important physiologic role in the 25-hydroxylation of vitamin D3 in chickens, providing novel insights into vitamin D3 metabolism in this species.

ABSTRACT: This study assessed the effects of combined supplementation with canthaxanthin (Cx) and 25-hydroxycholecalciferol (25-OH-D3) on incubation performance, fertility, and chick quality in European quail breeders. A total of 240 birds were distributed in a completely randomized design with 5 diets and 8 replicates. The animals were fed a basal diet containing 50 µg of vitamin D3 or the basal diet supplemented with 3 ppm Cx and 34.5 µg 25-OH-D3, 6 ppm Cx, and 69 µg 25-OH-D3, 9 ppm Cx and 103.5 µg 25-OH-D3, or 12 ppm Cx and 138 µg 25-OH-D3. Incubation performance was analyzed in 2 periods (32 and 38 wk). Breeders aged 32 wk produced eggs with higher hatchability (P = 0.024), hatchability of fertile eggs (P = 0.026) and lower initial plus mid embryonic mortality (P = 0.021), whereas 38-week-old breeders generated chicks with a higher length at hatching (P < 0.001) and lower final plus pipped embryonic mortality (P = 0.021). In both age groups, Cx + 25-OH-D3 levels had a quadratic effect on egg fertility (P < 0.001), hatchability of total (P < 0.001), and fertile eggs (P < 0.001). The fertility and the number of sperm cells in the perivitelline membrane was analyzed in two periods (26 and 40 wk). A quadratic effect of diet and days after mating on both parameters (P < 0.05) was observed. Eggs from supplementing breeders showed a high fertility (P < 0.001) and sperm cell counts (P < 0.001) for up to 7 and 3 d after mating, respectively, then the control group. Moreover, the supplementation of quail breeder diets with 6 ppm Cx + 69 µg 25-OH-D3 enhances sperm cell longevity in sperm storage tubules, hatchability of total and fertile eggs, fertility, and chick quality, especially in older quail's breeders and reduces embryonic mortality.

This study aimed to investigate the effect of supplementation with canthaxanthin (Cx) and 25-hydroxycholecalciferol (25-OH-D3) on the production performance, egg quality, bone mineral content, blood biochemical parameters, and antioxidant status of European quail breeders. Two hundred and forty quail breeders were distributed in a completely randomized design with 5 diets and 8 replicates of 4 females and 2 males were used. All quail breeders received one of 5 diets: basal diet (containing 2,000 IU vitamin D3) or the same diet supplemented with 3 ppm Cx and 34.5 μg 25-OH-D3, 6 ppm Cx and 69 μg 25-OH-D3, 9 ppm Cx and 103.5 μg 25-OH-D3, or 12 ppm Cx and 138 μg 25-OH-D3. Production performance and internal and external egg quality parameters were not influenced by diet. Eggshell dry weight decreased linearly with increasing supplementation levels, and eggshell ash and calcium content increased quadratically. Plasma phosphorus, calcium, and ionic calcium levels in females and plasma ionic calcium levels in males showed a positive quadratic response to dietary supplementation. Femoral and tibiotarsal dry weight and calcium content were influenced by diet. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity in the liver of males and females and in the serum of females showed a positive quadratic relationship with Cx and 25-OH-D3 levels, whereas the malonaldehyde concentration showed a negative quadratic relationship. DPPH scavenging activity in the serum of male quail increased linearly with supplementation. There was a positive quadratic effect on superoxide dismutase gene expression and a positive linear effect on glutathione peroxidase 7 gene expression, suggesting that dietary enrichment with Cx and 25-OH-D3 might help protect spermatozoa against oxidative damage. The dietary supplement was pro-oxidative at high concentrations (above 9 ppm Cx). The results indicate that diets with adequate levels of Cx and 25-OH-D3 have a beneficial effect on calcium and phosphorus metabolism as well as on the antioxidant defense system. We recommend supplementing European quail breeders in the laying period with 6 ppm Cx and 69 μg 25-OH-D3.

The influence of dietary vitamin D3 (VD3) levels on growth, bone performance, and duodenal type IIb sodium-dependent phosphate cotransporter (NaPi-IIb) genes in broiler chicken were studied. One-day-old male Ross308 broilers (n = 432) were allocated into 6 treatment groups with each group consisting of 6 cage pens. Each treatment group received diet containing different amounts of VD3 (80, 200, 500, 1,250, 3,125, or 7,813 IU per kg of diet) from a day-old to 31 D of age. Dietary available phosphorus and calcium were kept the same across all treatments in each phase. At 14 D, influence of VD3 on BW gain was found in the birds that received VD3 of 3,125 IU/kg and 200 IU/kg (P

Maintenance of calcium and phosphorus homeostasis in laying hens is crucial for preservation of skeletal integrity and eggshell quality, though physiological regulation of these systems is incompletely defined. To investigate changes in mineral and vitamin D 3 homeostasis during the 24-h egg formation cycle, 32-wk-old commercial laying hens were sampled at 1, 3, 4, 6, 7, 8, 12, 15, 18, 21, 23, and 24 h post-oviposition (HPOP ; n ≥ 4). Ovum location and egg calcification stage were recorded, and blood chemistry, plasma vitamin D 3 metabolites, circulating parathyroid hormone (PTH), and expression of genes mediating uptake and utilization of calcium and phosphorus were evaluated. Elevated levels of renal 25-hydroxylase from 12 to 23 HPOP suggest this tissue might play a role in vitamin D 3 25-hydroxylation during eggshell calcification. In shell gland, retinoid-x-receptor gamma upregulation between 6 and 8 HPOP followed by subsequently increased vitamin D receptor indicate that vitamin D 3 signaling is important for eggshell calcification. Increased expression of PTH, calcitonin, and fibroblast growth factor 23 (FGF23) receptors in the shell gland between 18 and 24 HPOP suggest elevated sensitivity to these hormones toward the end of eggshell calcification. Shell gland sodium-calcium exchanger 1 was upregulated between 4 and 7 HPOP and plasma membrane calcium ATPase 1 increased throughout eggshell calcification, suggesting the primary calcium transporter may differ according to eggshell calcification stage. Expression in shell gland further indicated that bicarbonate synthesis precedes transport, where genes peaked at 6 to 7 and 12 to 18 HPOP, respectively. Inorganic phosphorus transporter 1 ( P i T-1 ) expression peaked in kidney between 12 and 15 HPOP, likely to excrete excess circulating phosphorus, and in shell gland between 18 and 21 HPOP. Upregulation of FGF23 receptors and PiT-1 during late eggshell calcification suggest shell gland phosphorus uptake is important at this time. Together, these findings identified potentially novel hormonal pathways involved in calcium and phosphorus homeostasis along with associated circadian patterns in gene expression that can be used to devise strategies aimed at improving eggshell and skeletal strength in laying hens. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of supplementation with canthaxanthin (Cx) and 25- hydroxycholecalciferol (25-OH-D3) on the production performance, egg quality, bone mineral content, blood biochemical parameters, and antioxidant status of European quail breeders. Two hundred and forty quail breeders were distributed in a completely randomized design with 5 diets and 8 replicates of 4 females and 2 males were used. All quail breeders received one of 5 diets: basal diet (containing 2,000 IU vitamin D3) or the same diet supplemented with 3 ppm Cx and 34.5 mg 25-OH-D3, 6 ppm Cx and 69 mg 25-OH-D3, 9 ppmCx and 103.5 mg 25-OH-D3, or 12 ppmCx and 138 mg 25-OH-D3.Production performance and internal and external egg quality parameters were not influenced by diet. Eggshell dry weight decreased linearly with increasing supplementation levels, and eggshell ash and calcium content increased quadratically. Plasma phosphorus, calcium, and ionic calcium levels in females and plasma ionic calcium levels inmales showed a positive quadratic response to dietary supplementation. Femoral and tibiotarsal dry weight and calcium content were influenced by diet. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity in the liver of males and females and in the serum of females showed a positive quadratic relationship with Cx and 25-OH-D3 levels, whereas the malonaldehyde concentration showed a negative quadratic relationship. DPPH scavenging activity in the serum of male quail increased linearly with supplementation. There was a positive quadratic effect on superoxide dismutase gene expression and a positive linear effect on glutathione peroxidase 7 gene expression, suggesting that dietary enrichment with Cx and 25-OH-D3 might help protect spermatozoa against oxidative damage. The dietary supplement was pro-oxidative at high concentrations (above 9 ppm Cx). The results indicate that diets with adequate levels of Cx and 25-OH-D3 have a beneficial effect on calciumand phosphorus metabolismas well as on the antioxidant defense system.We recommend supplementing European quail breeders in the laying period with 6 ppm Cx and 69 mg 25-OH-D3. [ABSTRACT FROM AUTHOR]

The influence of dietary vitamin D3 (VD3) levels on growth, bone performance, and duodenal type IIb sodium-dependent phosphate cotransporter (NaPi-IIb) genes in broiler chickenwere studied. One-day-old male Ross 308 broilers (n 5 432) were allocated into 6 treatment groups with each group consisting of 6 cage pens. Each treatment group received diet containing different amounts of VD3 (80, 200, 500, 1,250, 3,125, or 7,813 IU per kg of diet) from a day-old to 31 D of age. Dietary available phosphorus and calcium were kept the same across all treatments in each phase. At 14 D, influence of VD3 on BW gain was found in the birds that received VD3 of 3,125 IU/kg and 200 IU/kg (P, 0.05). Toe ash and tibia ash linearly increased (P,0.05) at 14 D with increase in dietary VD3. There was no significant influence of dietary VD3 on tibia breaking strength. In both phases, relative expression of duodenal NaPi-IIb linearly increased (P,0.01) with increase in dietary VD3. At 14 D, highest expression of 3.2 folds was observed in birds treated with VD3 at 7,813 IU/kg of feed. At 31 D, birds that received VD3 levels of 3,125 and 7,813 IU/kg of feed showed 2.9 folds higher in NaPi-IIb expression compared with those fed lowest level of VD3 at 80 IU/kg of feed. When dietary calcium and phosphorus were maintained at the standard requirement, increase in dietary VD3 did not improve growth performance. For optimum growth and bone characteristics, dietary inclusion of VD3 at 500 IU/kg was adequate for both starter and grower broiler diets. Vitamin D3 enhanced the expression of NaPi-IIb at higher doses and thus improving the tibia ash content in high VD3 treatment groups. This study reported for the first time an increased in the expression of duodenal NaPi-IIb in 31-day-old broilers in response to high dietary VD3 levels. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to investigate the effects of various dietary concentrations of vitamin D3 (D3) on pullet and laying hen performance, eggshell quality, bone health, and yolk D3 content from day of hatch until 68 wk of age. Initially, 440 Hy-line W36-day-old chicks were randomly assigned to 5 dietary treatments: 1,681 (control); 8,348; 18,348; 35,014; 68,348 IU D3/kg. At 17 wk of age, pullets were assigned to experimental diets with 12 replicate groups of 6 birds. At 17 wk of age, pullets fed diets containing 8,348 and 35,014 IU D3/kg had an increased bone mineral density in comparison to the control fed birds (P ≤ 0.01). Body weights of pullets fed the diet with 68,348 IU D3/kg were lower than other treatments (P ≤ 0.01). Hen-housed egg production (HHEP) of hens fed the 35,014 IU D3/kg diet was increased in comparison to control-fed hens (P ≤ 0.01), whereas HHEP of those fed 68,348 IU D3/kg diet was reduced in comparison to all other treatments (P ≤ 0.01). Shell breaking strength of eggs from hens fed 8,348, 35,014 and 68,348 IU D3/kg was increased in comparison to eggs from control-fed birds (P ≤ 0.01). Fat-free tibia ash content of hens fed any of the diets supplemented with D3 (8,348 to 68,348 IU D3/kg) was increased in comparison to control-fed hens (P ≤ 0.05). Yolk D3 content increased linearly with dietary D3 and the D3 transfer efficiency for the control, 8,348 IU, 18,348 IU, 35,014 IU, and 68,348 IU D3 treatments were 8.24, 10.29, 11.27, 12.42, and 12.06%, respectively. These data suggest that supplementation of dietary D3 up to 35,014 IU D3/kg feed maintained if not increased laying hen performance and enhanced pullet and laying hen skeletal quality as well as yolk D3 content and eggshell quality. Feeding pullets at a higher level 68,348 IU of D3 resulted in reduced growth and ultimately decreased performance of laying hens. [ABSTRACT FROM AUTHOR]

The present study was conducted to develop a non-traditional vitamin D3 (D3) intake bioassay with the objective of increasing the precision of D3 delivery to the chickens. For this purpose, newly hatched chickens (5 birds per cage) were allocated in battery brooders and randomly distributed into 8 treatments and 6 replicates per treatment. A basal corn-soy diet devoid of D3 containing calculated calcium and non-phytate phosphorus concentrations of 0.90 and 0.45%, respectively, was fed throughout a 21-D period. The first 9 D of the study served to deplete the maternal stores of D3 followed by a 12-h fasting period. From day 10 to the end of the trial, the birds were gavaged with graded levels of D3 obtained from a highly purified pharmaceutical grade D3 standard (99.8%) purchased from Sigma-Aldrich and dissolved in corn oil. Daily gavage treatments were based on estimated intake of 0, 50, 100, 200, 400, 800, 1,600, and 3,200 IU D3/kg of feed consumed over the last 12 D of the study. Precise cholecalciferol intake per kg of diet was adjusted based on actual daily feed intake per pen of birds. Performance data were evaluated from day 10 to 21. Percent tibia bone ash (TBA), tibia breaking strength (TBS), total mineral content, and total bone mineral density were obtained at day 21. The D3 treatments improved (P < 0.05) weight gain and feed efficiency. There was no linear or quadratic effect for any of the productivity performance variables. Graded levels of D3 improved (P < 0.05) TBA and TBS. Both were linearly increased (P < 0.05) in response to graded levels of D3. A quadratic response was observed for TBS only. Under the conditions of the present experiment and the average of 3 regression models, the D3 requirement for starter broilers was estimated at 285 IU D3/kg of feed when bone mineralization responses (TBA and TBS) were used as criteria to estimate the requirement. [ABSTRACT FROM AUTHOR]

A total of 800 1-day-old Ross 308 male broiler chicks were used in a 5-wk feeding trial to evaluate the effects of commercial feed additive that is composed of blends of essential oil (EO; CRINA Poultry, DSM) and vitamin D3. The birds were randomly assigned to 5 treatments with 10 replicate cages; each stocked with 16 birds and was fed corn–soybean-meal-based basal diet. Dietary treatments included: CON, unvaccinated birds fed basal diet/control; CCO, CON + coccidian oocysts vaccinated birds; EOD1, CCO + Essential oil blends and vitamin D/Prototype 1 (50 μg 25-OH-D3/kg diet, 15 mg CRINA Poultry/kg diet); EOD2, CCO + Prototype 2 (69 μg 25-OH-D3/kg diet, 30 mg CRINA Poultry/kg diet); and EOD3, CCO + Prototype 3 (138 μg 25-OH-D3/kg diet, 50 mg CRINA Poultry/kg diet). On day 7, all birds, except CON, were inoculated with 300 to 500 purified sporulated viable oocysts from Eimeria tenella and Eimeria maxima. As a result of this study, the supplementation of EO blends with vitamin D3 showed trends in improvement (P = 0.075) body weight gain (BWG) compared with CON and CCO during the grower phase (day 7 to 21). An increase (P < 0.05) in BWG and reduction (P < 0.05) in feed conversion ratio (FCR) were observed in birds fed EOD2 diet during day 21 to 35 compared with vaccinated birds without feed additive. The cumulative performance during overall period (day 1 to 35) also showed that BWG was increased and FCR was reduced in EOD2 and EOD3 compared with CON, CCO, and EOD1. Furthermore, the apparent total tract digestibility of dry matter tended (P = 0.06) to increase in EOD2 and EOD3 compared with CON and other treatments. The EOD2 and EOD3 treatments showed increased (P < 0.05) excreta Lactobacillus counts than EOD1. The intestinal lesion score induced by E. tennela in gastro-intestinal tract was lower (P < 0.05) in EOD1, EOD2, and EOD3 treatments compared with CCO. In conclusion, blends of EO and vitamin D3 could be used as anti-coccidial feed additive in broilers with coccidian infection. [ABSTRACT FROM AUTHOR]

Vitamin D 3 is hydroxylated by cytochrome P450 (CYP) before exerting biological effects. The chicken CYP involved in vitamin D 3 25-hydroxylation has yet to be cloned, and little is known about its functional characteristics, tissue distribution, and cellular expression. We identified a novel, full-length CYP27A1 gene cloned from chicken hepatocyte cDNA that encodes a putative protein of 518 amino acids. Swiss modeling revealed that chicken CYP27A1 has a classic open-fold form. Multisequence homology alignment determined that CYP27A1 contains conserved motifs for substrate recognition and binding. Quantitative real-time PCR analysis in 2-mo-old Partridge Shank broilers demonstrated that CYP27A1 mRNA levels were highest in the liver, followed by the thigh muscles, the breast muscles, and kidneys. The transcripts of CYP27A1 in breast muscles were significantly higher in males than in females. A subcellular localization analysis demonstrated that CYP27A1 was mainly expressed in the mitochondria. In vitro enzyme assays suggested that recombinant CYP27A1 hydroxylates vitamin D 3 at the C-25 position to form 25-hydroxyvitamin D 3 (25(OH)D 3). The K m and V max values for CYP27A1-dependent vitamin D 3 25-hydroxylation were estimated to be 4.929 μM and 0.389 mol min−1 mg−1 protein, respectively. In summary, these results suggest that CYP27A1 encodes a mitochondrial CYP that plays an important physiologic role in the 25-hydroxylation of vitamin D 3 in chickens, providing novel insights into vitamin D 3 metabolism in this species. [ABSTRACT FROM AUTHOR]

Decreasing feed costs while maintaining broiler performance at a high level with minimal environmental pollution has become a major challenge for poultry nutritionists in recent years. In this regard, phosphorus (P) is a nutrient that is problematic. To overcome this, a comprehensive knowledge of the responses of broilers to P is needed and the factors that affect its utilization need better understanding. For this purpose, a meta-analysis was conducted using results published in the literature on the responses of broilers to different levels of nonphytate P (NPP), calcium (Ca), microbial phytase (MP), and vitamin D3 or its metabolites (VD). The effects of Ca, MP, and VD on NPP requirements were investigated. Results showed significant (P ≤ 0.0001) linear and quadratic effects of NPP on all the responses, viz. average daily gain (ADG), feed intake (FI), feed efficiency (FE), and tibia ash concentration (TA). Results showed the negative effect of high Ca levels on all investigated responses, although these deleterious effects were alleviated when levels of NPP were increased or MP and/or VD added. Synergistic effects of MP and VD on FI and TA were observed. Best performance for all responses was found when MP and VD were added to low or moderate levels of Ca and NPP. Optimization showed higher levels of NPP are required to maximize TA compared to ADG, FI, and FE. Based on our analysis, requirements for NPP were affected mostly by Ca (increased) and MP (decreased), and, to a lesser extent, VD (inconsistent). [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the effect of in ovo feeding (IOF) with inorganic minerals or organic minerals and vitamin D3 on bone properties and mineral consumption. Eggs were incubated and divided into 4 groups: IOF with organic minerals, phosphate, and vitamin D3 (IOFOMD); IOF with inorganic minerals and phosphate (IOF-IM); sham; and non-treated controls (NTC). IOF was performed on embryonic day (E) 17; tibiae and yolk samples were taken on E19 and E21. Post-hatch, only chicks from the IOF-OMD, sham, and NTC were raised, and tibiae were taken on d 10 and 38. Yolk mineral content was examined by inductively coupled plasma spectroscopy. Tibiae were tested for their whole-bone mechanical properties, and mid-diaphysis bone sections were indented in a micro-indenter to determine bone material stiffness (Young's modulus). Micro-computed tomography (μCT) was used to examine cortical and trabecular bone structure. Ash content analysis was used to examine bone mineralization. A latency-to-lie (LTL) test was used to measure standing ability of the d 38 broilers. The results showed that embryos from both IOF-OMD and IOF-IM treatments had elevated Cu, Mn, and Zn amounts in the yolk on E19 and E21 and consumed more of these minerals (between E19 and E21) in comparison to the sham and NTC. On E21, these hatchlings had higher whole-bone stiffness in comparison to the NTC. On d 38, the IOF-OMD had higher ash content, elevated whole-bone stiffness, and elevated Young's modulus (in males) in comparison to the sham and NTC; however, no differences in standing ability were found. Very few structural differences were seen during the whole experiment. This study demonstrates that mineral supplementation by in ovo feeding is sufficient to induce higher mineral consumption from the yolk, regardless of its chemical form or the presence of vitamin D3. Additionally, IOF with organic minerals and vitamin D3 can increase bone ash content, as well as stiffness of the whole bone and bone material in the mature broiler, but does not lead to longer LTL. [ABSTRACT FROM AUTHOR]

This study assessed the effects of combined supplementation with canthaxanthin (Cx) and 25-hydroxycholecalciferol (25-OH-D 3) on incubation performance, fertility, and chick quality in European quail breeders. A total of 240 birds were distributed in a completely randomized design with 5 diets and 8 replicates. The animals were fed a basal diet containing 50 µg of vitamin D 3 or the basal diet supplemented with 3 ppm Cx and 34.5 µg 25-OH-D 3 , 6 ppm Cx, and 69 µg 25-OH-D 3 , 9 ppm Cx and 103.5 µg 25-OH-D 3 , or 12 ppm Cx and 138 µg 25-OH-D 3. Incubation performance was analyzed in 2 periods (32 and 38 wk). Breeders aged 32 wk produced eggs with higher hatchability (P = 0.024), hatchability of fertile eggs (P = 0.026) and lower initial plus mid embryonic mortality (P = 0.021), whereas 38-week-old breeders generated chicks with a higher length at hatching (P < 0.001) and lower final plus pipped embryonic mortality (P = 0.021). In both age groups, Cx + 25-OH-D 3 levels had a quadratic effect on egg fertility (P < 0.001), hatchability of total (P < 0.001), and fertile eggs (P < 0.001). The fertility and the number of sperm cells in the perivitelline membrane was analyzed in two periods (26 and 40 wk). A quadratic effect of diet and days after mating on both parameters (P < 0.05) was observed. Eggs from supplementing breeders showed a high fertility (P < 0.001) and sperm cell counts (P < 0.001) for up to 7 and 3 d after mating, respectively, then the control group. Moreover, the supplementation of quail breeder diets with 6 ppm Cx + 69 µg 25-OH-D 3 enhances sperm cell longevity in sperm storage tubules, hatchability of total and fertile eggs, fertility, and chick quality, especially in older quail's breeders and reduces embryonic mortality. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of varying dietary vitamin D3 and stocking den-sity on growing performance, carcass characteristics, bone biomechanical properties, and welfare responses in Ross (308) broilers. Experimental diets, containing 1, 10, or 20 times the NRC recommended level of vitamin D3 (200 IU/kg), were formulated with low, medium, or high vitamin D3 levels for 3 growing phases. Two stocking densities were 10 and 16 birds/m². One-day-old hatchlings (1,872 males) were randomly assigned to 6 pens in each treatment. Results showed that high stocking density decreased the feed intake, BW gain (P < 0.01), breast muscle yield (P = 0.010), and tibial development (P < 0.01), whereas increasing feed conver-sion ratio (P < 0.001), and the scores of gait, footpad and hock burn, and abdominal plumage damage (P < 0.01), particularly toward the age when birds attained their market size. Increasing dietary vitamin D3 im-proved the birds' walking ability and tibial quality (P < 0.05), and reduced the development of footpad or hock dermatitis and abdominal plumage damage (P < 0.01), some aspects of which were age-dependent and appeared to vary with stocking density. These data in-dicate that increasing supplemental vitamin D3 has a favorable effect on walking ability and welfare status of high stocking density birds, but not on performance. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the quality of eggs from 2 selected commercial strains of laying hens and 2 unselected lines of chickens fed diets with different combinations of Ca and vitamin D and relate it to the profile of uterine proteins and ultrastructure of the shell. A group of 4 chickens was housed in each of 24 cages. The group consisted of one representative from each of the following breeds: Lohmann LSL- Lite, Lohmann Classic-Brown, Fayoumi, and Light Sussex. Six dietary combinations of Ca and vitamin D3 (3.35%, 2,500 IU; 4.10%, 2,500 IU (control); 4.85%, 2,500 IU; 3.35%, 200 IU; 4.10%, 200 IU; and 4.85%, 200 IU) were randomly assigned to 4 replicate cages for 2 treatment periods (26-29 and 56-59 wk of age). Data were analyzed as a split-plot design with cage as the main plot and hen as the subplot. Egg quality traits were different (P < 0.0001) between commercial and heritage breeds. Lohmann Brown had stronger shells with higher specific gravity compared with other breeds. Both commercial and heritage birds responded to a drop in vitamin D3 level by marked reduction in shell thickness. The SDS-PAGE profiles of uterine fluid samples revealed a decrease (P < 0.05) in 200-, 150-, 116-, and ≤6.5-kDa proteins, whereas proteins with molecular weight (MW) of 80, 55, 52, 45, 42, and 28 kDa increased with bird age. A 36- and 52-kDa protein band was most intense for Fayoumi compared with other breeds. Ultrastructural characteristics showed flattened and deeply etched mammillary caps for Lohmann Brown and the presence of type A and type B bodies between mammillary cones in eggshells from Fayoumi and Lohmann Lite. The negative correlation between ultrastructural characteristics, which decrease with bird age, and the 116-kDa uterine protein band could provide insight into reduced eggshell quality as hens age. [ABSTRACT FROM AUTHOR]

An experiment was conducted with 25- to 66-wk-old Ross broiler breeders in an environment excluding ultraviolet light to determine the cholecalciferol (D3) requirements for hen day egg production; hatchability; body weight of the progeny at 1 d; embryo mortality during the early (1 to 10 d of incubation), middle (11 to 15 d of incubation), and late stages (16 to 21 d of incubation) of development; egg weight; specific gravity; and body ash of the progeny at 1 d of age. Five levels of vitamin D3 (125, 250, 500, 1,000, and 2,000 IU/kg of diet) were fed to hens from 25 to 66 wk of age. One additional group was fed no supplemental D3 until 36 wk of age and was then changed to 4,000 IU/kg of diet. Separate regression analyses were performed for wk 27 to 36 (peak original design) and for wk 37 to 66 (postpeak production modified design). The D3 levels for the predicted maximum hen day egg production during peak and postpeak were 1,424 and 2,804 IU/kg, respectively. The D3 levels for the predicted maximum hatchability were 1,390 IU/ kg (peak) and 2,708 IU/kg (postpeak). The level of D3 that resulted in the minimum early embryo mortality was 1,288 IU/kg at peak; however, no significant effect was observed at postpeak. The D3 levels for minimum middle stage embryo mortality were 1,130 IU/kg (peak) and 2,568 IU/kg (postpeak) and for late stage embryo mortality were 1,393 IU/kg (peak) and 2,756 IU/kg (postpeak). The D3 level for maximum egg weight was 1,182 IU/kg (peak) and for specific gravity was 1,337 IU/kg (peak) and >2,000 IU/kg (postpeak). The D3 level for maximum body ash of progeny at d 1 was >2,000 IU/kg. Analysis of the data from the original design of the experiment (treatments providing 0, 125, 250, 500, 1,000, and 2,000 IU of vitamin D3/kg for the 27- to 36-wk-old birds) indicates a requirement of approximately 1,400 IU of D3/kg of feed for broiler breeder hens. When the data from the modified experiment (37 to 66 wk of age) include conversion of the treatment provided at 0 IU of D3/kg to a treatment providing 4,000 IU of D3/kg, the requirement may be approximately 2,800 IU of D3/kg. [ABSTRACT FROM AUTHOR]

An experiment was conducted with broiler breeder hens to determine the relative biological value of 25-hydroxycholecalciferol (25-OHD3) compared with cholecalciferol (vitamin D3) for hen-day egg production, hatchability, embryo mortality (early, 1 to 10 d of incubation, late, 11 to 21 d), and body ash of the progeny. The study was conducted with 73-to-90-wk-old molted Ross broiler breeder hens in an environment excluding ultraviolet light. A basal vitamin D3 deficient diet supplemented with 4 levels of vitamin D3 (0, 3,125, 12,500, and 50,000 ng/kg of diet) and 2 levels of 25-OHD3 (3,125 and 12,500 ng/kg of diet) was fed. The relative biological values of 25-OHD3 in comparison to vitamin D3, using slope ratio techniques, were 138, 133, 128, and 111% for hen-day egg production, hatchability, late embryo mortality, and body ash of the progeny, respectively (average = 128%). When comparing 25-OHD3 against D3 at the 3,125 ng/kg level, the relative biological values were 209, 167, 400, and 108% for the same criteria, respectively (average = 221%). However, at the 12,500 ng/kg level no statistical differences between 25-OHD3 and D3 were observed (average = 108%). Four trials were conducted to determine the effect of the maternal diet on the performance and leg abnormalities of the hens' progeny. In experiment 1, no vitamin D was added to the corn-soybean meal basal diet fed to the chicks, and in experiments 2, 3, and 4 the basal diet was supplemented with 27.5 µg of D3/kg of diet. In the progeny study, the average relative biological value of 25-OHD3 at the 3,125 and 12,500 ng/kg levels were 115 and 101%, respectively. The potency of 25-OHD3 in relation to vitamin D3 depended on the level tested. When comparing vitamin D sources, 25-OHD3 had greater potency than D3 only at very low levels of supplementation. [ABSTRACT FROM AUTHOR]

Higher concentrations of Ca in the diet may decrease phytate-phosphorus hydrolysis because of chelation of Ca with the phytin molecule. In experiment 1, drakes were fed 0.74, 0.85, 0.95, or 1.11% Ca (analyzed) from 7 to 18 d of age (6 birds/cage, 8 cages/diet). Intestinal mucosa was collected at 18 d of age from birds fed 0.74 and 1.11% Ca for determination of intestinal phytase activity. In experiment 1, 17 d BW gain and feed consumption exhibited a quadratic response to increasing concentrations of Ca and were found to be maximal for ducks fed the 0.95% Ca diet. Toe ash percentage (18 d) had a quadratic response to increasing concentrations of Ca with a maximal response for birds fed the 0.85% Ca diet. Increasing dietary Ca did not affect P retention from 15 to 17 d of age or intestinal phytase activity and brush border vesicle Ca concentration. A positive correlation was found between the Vmax and the Ca concentration within the vesicles (r = 0.59, P < 0.02), suggesting that the vesicle Ca concentration did not negatively affect the kinetics of the phytase assay. In experiment 2, drakes were fed 0.6, 0.8, 1.0, or 1.2% Ca (formulated) with 826 or 8,260 ICU/kg of vitamin D3 from 0 to 13 d of age. There was no response to increasing concentrations of Ca for performance characteristics or bone ash measurements. [ABSTRACT FROM AUTHOR]

Presents abstracts of several studies on the physiology of poultry animals. "Differential Expression of Mitochondrial and Extra-Mitochondrial Proteins in Heart of Low and High Feed Efficient Broilers Within a Single Male Line," by N. Tinsely et al; "Aorta Pulse Wave Velocity Is Reduced by Intravenous Injections of L-Arginine in Female, But Not Male, White Leghorn Chickens," by C. A. Ruiz-Feria and H. Nishimura; "Pulmonary and Systemic Hemodynamic Responses to Prostacyclin in Broilers," by R. F. Wideman and M. E. Chapman.

Presents abstracts of several studies about amino acids and vitamin/mineral nutrition. "Evaluation of Guar By-Products in High Production Laying Hen Diets," by C. Zhang, A. L. Cartwright, J. B. Carey, and C. A. Bailey; "Effect of Dietary Nutrient Density, Feed Form, and Lighting on the Growth Performance of Broiler Chickens," by K. E. Brickett and H. L. Classen; "Satellite Cell Mitotic of Broilers Receiving Lysine Deficient Diets," by S. Pophal, P. Mozdziak, and S. Vieira; "Synthetic Methionine and Feed Restriction Effects on Performance and Meat Quality of Organically Reared Broiler Chickens in the Summer Months," by A. S. Parsons, N. J. Baker, and J. S. Moritz.

The objective of this experiment was to investigate the effects of various dietary concentrations of vitamin D3 (D3) on pullet and laying hen performance, eggshell quality, bone health, and yolk D3 content from day of hatch until 68 wk of age. Initially, 440 Hy-line W36-day-old chicks were randomly assigned to 5 dietary treatments: 1,681 (control); 8,348; 18,348; 35,014; 68,348 IU D3/kg. At 17 wk of age, pullets were assigned to experimental diets with 12 replicate groups of 6 birds. At 17 wk of age, pullets fed diets containing 8,348 and 35,014 IU D3/kg had an increased bone mineral density in comparison to the control fed birds (P ≤ 0.01). Body weights of pullets fed the diet with 68,348 IU D3/kg were lower than other treatments (P ≤ 0.01). Hen-housed egg production (HHEP) of hens fed the 35,014 IU D3/kg diet was increased in comparison to control-fed hens (P ≤ 0.01), whereas HHEP of those fed 68,348 IU D3/kg diet was reduced in comparison to all other treatments (P ≤ 0.01). Shell breaking strength of eggs from hens fed 8,348, 35,014 and 68,348 IU D3/kg was increased in comparison to eggs from control-fed birds (P ≤ 0.01). Fat-free tibia ash content of hens fed any of the diets supplemented with D3 (8,348 to 68,348 IU D3/kg) was increased in comparison to control-fed hens (P ≤ 0.05). Yolk D3 content increased linearly with dietary D3 and the D3 transfer efficiency for the control, 8,348 IU, 18,348 IU, 35,014 IU, and 68,348 IU D3 treatments were 8.24, 10.29, 11.27, 12.42, and 12.06%, respectively. These data suggest that supplementation of dietary D3 up to 35,014 IU D3/kg feed maintained if not increased laying hen performance and enhanced pullet and laying hen skeletal quality as well as yolk D3 content and eggshell quality. Feeding pullets at a higher level 68,348 IU of D3 resulted in reduced growth and ultimately decreased performance of laying hens., (© 2019 Poultry Science Association Inc.)

The present study was conducted to develop a non-traditional vitamin D3 (D3) intake bioassay with the objective of increasing the precision of D3 delivery to the chickens. For this purpose, newly hatched chickens (5 birds per cage) were allocated in battery brooders and randomly distributed into 8 treatments and 6 replicates per treatment. A basal corn-soy diet devoid of D3 containing calculated calcium and non-phytate phosphorus concentrations of 0.90 and 0.45%, respectively, was fed throughout a 21-D period. The first 9 D of the study served to deplete the maternal stores of D3 followed by a 12-h fasting period. From day 10 to the end of the trial, the birds were gavaged with graded levels of D3 obtained from a highly purified pharmaceutical grade D3 standard (99.8%) purchased from Sigma-Aldrich and dissolved in corn oil. Daily gavage treatments were based on estimated intake of 0, 50, 100, 200, 400, 800, 1,600, and 3,200 IU D3/kg of feed consumed over the last 12 D of the study. Precise cholecalciferol intake per kg of diet was adjusted based on actual daily feed intake per pen of birds. Performance data were evaluated from day 10 to 21. Percent tibia bone ash (TBA), tibia breaking strength (TBS), total mineral content, and total bone mineral density were obtained at day 21. The D3 treatments improved (P < 0.05) weight gain and feed efficiency. There was no linear or quadratic effect for any of the productivity performance variables. Graded levels of D3 improved (P < 0.05) TBA and TBS. Both were linearly increased (P < 0.05) in response to graded levels of D3. A quadratic response was observed for TBS only. Under the conditions of the present experiment and the average of 3 regression models, the D3 requirement for starter broilers was estimated at 285 IU D3/kg of feed when bone mineralization responses (TBA and TBS) were used as criteria to estimate the requirement., (© 2019 Poultry Science Association Inc.)