The Vitamin D3 Requirement of Broiler Breeders

Genotype-dependent impact of dietary vitamin D3 on laying hens

Vitamin D₃ has an integral part in calcium and phosphorus homoeostasis, which in turn plays a key role in egg production of hens. The present study aimed to investigate whether an additional vitamin D₃ supplementation improves the laying performance and egg quality of hens according to their genetic potential. For this purpose, four layer lines (low performing: R11 and L68; high performing: WLA and BLA) supplemented either with 300 or 3000 IU vitamin D₃ per kg feed were compared concerning serum 25-hydroxyvitamin D₃ (25-OHD₃), calcium, phosphorus and alkaline phosphatase (ALP), laying performance and egg quality. The higher supplementation of vitamin D₃ increased 25-OHD₃ serum concentrations in all genotypes, except for R11 and WLA hens in week 49, and also elevated vitamin D₃ and 25-OHD₃ content in the egg yolk (p < 0.05). In week 29, 3000 IU vitamin D₃ decreased pooled least squares means (LSMeans) of serum calcium concentrations considering all genotypes and increased the ALP concentrations in BLA hens (p < 0.05). Considering the whole experimental period daily egg mass of R11 hens was increased by an additional vitamin D₃ supplementation (p < 0.001). Regarding all genotypes and the whole experimental period the pooled LSMeans of breaking strength of eggs from hens fed 3000 IU vitamin D₃ were higher than those of hens fed 300 IU (p = 0.044). In conclusion, present results give evidence that the higher vitamin D₃ supplementation might have genotype-dependently beneficial effects on calcium and phosphorus homoeostasis of hens, which might improve feed efficiency in the early laying period and promote the persistence of the laying period irrespectively of genotype. The increase of serum 25-OHD₃ by the higher vitamin D supplementation supported the higher transfer of vitamin D in the egg yolk and improved genotype-dependently the breaking strength of the eggshell.

Supranutrition of microalgal docosahexaenoic acid and calcidiol improved growth performance, tissue lipid profiles, and tibia characteristics of broiler chickens

BACKGROUND

Docosahexaenoic acid (DHA) and calcidiol could be enriched in chicken for improving public nutrition and health. It remains unclear if supranutritional levels of DHA and calcidiol impair growth performance or metabolism of broiler chickens. This study was to determine singular and combined effects of high levels of supplemental DHA-rich microalgal biomass or oil and calcidiol on growth performance, concentrations of triglycerides, cholesterol, and nonesterfied fatty acids in plasma, liver, breast, and thigh, and biophysical properties of tibia.

METHODS

In Exp. 1, 144 day-old Cornish chicks were divided into 4 groups (6 cages/treatment, 6 birds/cage), and were fed a corn-soybean meal basal diet (BD), BD + 10,000 IU calcidiol/kg (BD + Cal), BD + 1% DHA-rich Aurantiochytrium (1.2 g DHA/kg; BD + DHA), and BD + Cal + DHA for 6 weeks. In Exp. 2, 180 day-old chicks were divided into 5 groups, and were fed: BD, BD + DHA (0.33% to 0.66% oil, 1.5 to 3.0 g DHA/kg), BD + DHA + EPA (1.9% to 3.8% eicosapentaenoic acid-rich Nannochloropsis sp. CO18, 0.3 to 0.6 g EPA/kg), BD + DHA + calcidiol (6000 to 12,000 IU/kg diet), and BD + DHA + EPA + Cal for 6 weeks.

RESULTS

Birds fed BD + Cal diet in Exp. 1 and BD + DHA + EPA diet in Exp. 2 had higher (P < 0.05) body weight gain (10%-11%) and gain:feed ratio (7%), and lower (P < 0.05) total cholesterol and triglyceride concentrations in plasma (18%-54%), liver (8%-26%), breast (19%-26%), and thigh (10%-19%), respectively, over the controls. The two diets also improved (P < 0.05) tibial breaking strength (8%-24%), total bone volume (2%-13%), and (or) bone mineral density (3%-19%) of chickens.

CONCLUSION

Supranutrition of dietary calcidiol and DHA alone or together did not produce adverse effects, but led to moderate improvements of growth performance, lipid profiles of plasma and muscle, and bone properties of broiler chickens.

Reproductive performance, expression of TRAP6 and TGF-β4 genes in utero-vaginal junction mucosa, and indicators of liver function in female Chukar partridge (Alectoris chukar) breeders fed with fish oil and calcitriol during the egg-laying period

Reproductive attributes, expression of TRAP6 and TGF-β mRNA in the mucosa of the utero-vaginal junction (UVJ) of oviduct, and liver function were evaluated in Chukar partridge (Alectoris chukar) breeders subjected to long-term oral administration of fish oil (FO) and/or calcitriol (CT). A total of forty-eight 1.5-year-old laying Chukar partridges and 16 age-matched males (female:male ratio of 3:1) were randomly allocated to four groups (4 replicates of 3 female birds and one male bird each). Breeder females in groups 1, 2, and 3 were orally administered daily with 0.2 mL (0.24 g)/500 g body weight FO, 0.2 mL solution containing 10 μg CT, or their combination (FO + CT) for 42 successive days, respectively. Pure crystalline calcitriol was dissolved in ethanol (30%) prior to administration. The control group (CON), received a similar volume of a 30% solution of ethanol only. Eggs were collected and incubated to evaluate the reproductive performance. Blood samples were taken on days 0, 21, and 42 of the trial for the quantification of serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). On day 43, one bird per replicate was killed by cervical dislocation to assess the expression of TRAP6 and TGF-β genes in the UVJ mucosa. Administration of CT or FO + CT increased the egg production rate, fertility rate, and hatchability rate of the set eggs. Fertility duration and sperm penetration rate were higher in partridges receiving FO and (or) CT, but chick quality, and embryonic mortality were not affected by the treatment effect. Administration of CT or FO + CT decreased the serum ALT and AST levels. Administration of FO or CT was associated with a lower expression of TGF-β mRNA in the UVJ mucosa. Oral administration of FO resulted in a reduction in the expression of TRAP6 in the UVJ mucosa. However, the birds fed with CT or FO + CT recorded a higher mRNA expression for TRAP6. Although the reproductive performance and TRAP6 expression were higher following the feeding of FO or FO + CT, expression of TGF-β was decreased, suggesting plausibly that TGF-β may not have a determinant effect on the reproductive attributes in female Chukar partridges. Further studies are required to understand the mechanisms underlying the effects of TRAP6 and TGF-β on other reproductive criteria in partridges.

UV-light and dietary vitamin D and their effects on ionized calcium and 25-OH-D plasma concentrations in captive gentoo penguins (Pygoscelis papua)

In this study, the effect of ultraviolet (UV) light and dietary vitamin D on calcium metabolism in permanently indoor-housed gentoo penguins (Pygoscelis papua) was investigated. The study consisted of three periods, each completed with blood samples to analyse plasma concentrations of 25-OH-D, 1,25-(OH)₂ -D, ionized (iCa) and total calcium (tCa). During the first study period (D), animals were housed under routine conditions without UV-light and fed a diet of different fish species, supplemented with 1,000 IU vitamin D per animal and day. The following study period (Baseline) of 28-day duration consisted of the same diet without any vitamin D supplementation and without UV-light. During the study period (UVB) artificial UV-light was added for 3 weeks. The vitamin D content of fish was measured by high-performance liquid chromatography. It varied between fish species and between facilities, ranging from no measurable content in capelin (Mallotus villosus) to 7,340 IU vitamin D/kg original matter (OM) in herring (Clupea spp). The average dietary vitamin D content was 311 IU/kg OM at facility 1 and 6,325 IU/kg OM at facility 2, resulting in a vitamin D intake per animal and day without supplementation of 130 IU (25.5 IU/kg body weight BW) and 2,454 IU (438.2 IU/kg BW) respectively. The supplementation of vitamin D elevated significantly the plasma concentrations of 25-OH-D by an intraindividual difference of 15 (range -2 to 59) nmol/L and tCa by 0.1 (0.0-0.3) mmol/L only at facility 2. The exposure to UV-light raised the blood concentrations of tCa at facility 2 by 0.15 (0.1-0.2) mmol/L, and of iCa and tCa for females at facility 1 by 0.23 (0.13-0.41) mmol/L and 1.8 (1.1-2.5) mmol/L respectively. No significant influence of the study periods (D) and (UVB) was found for the concentrations of 1,25-(OH)₂ -D at both facilities.

Effects of Maternal and Progeny Dietary Vitamin Regimens on the Performance of Ducklings

This study evaluated the interaction effect of maternal and progeny vitamin regimens on the performance of ducklings. At 38 weeks of age, 780 female and 156 male duck breeders were fed either regular or high vitamin premix diet (maternal high premix had higher levels of all vitamins except K₃ than maternal regular premix) for 16 weeks. Ducklings hatched from eggs laid at the end of the duck breeder trial were kept separate according to maternal treatment and were fed 2 levels of vitamin premix (NRC and high, progeny high premix had higher levels of all vitamins except biotin than progeny NRC premix) for 35 days. Body weight (P<0.001) and tibia ash (P=0.033) of 1-day-old ducklings and serum total superoxide dismutase activity of 14-day-old ducklings (P=0.027) were increased by maternal high vitamin premix. Progeny high vitamin premix increased body weight (14 days, P=0.019; 35 days, P=0.034), body weight gain (1–14 days, P=0.021; 1–35 days, P=0.034), gain:feed ratio (1–14 days, P<0.001), feed intake (15–35 days, P=0.037), serum total antioxidant capacity (14 days, P=0.048; 35 days, P=0.047), and serum calcium (14 days, P=0.007), and decreased serum malondialdehyde (14 days, P=0.038; 35 days, P=0.031) of ducklings. Maternal vitamin premix–progeny vitamin premix interaction significantly affected body weight (14 days, P=0.029), body weight gain (1–14 days, P=0.029), and feed intake (1–14 days, P=0.018) of progeny ducklings. Briefly, progeny NRC premix decreased the growth performance (days 1–14) of ducklings from maternal regular vitamin group, but not duckling from maternal high vitamin group. The results demonstrate a shortcoming of current vitamin recommendations for ducklings and suggest that the vitamin needs of starter ducklings can be met by either maternal or progeny vitamin supplementation.

THE EFFECT OF UVB RADIATION ON SERUM VITAMIN D AND IONIZED CALCIUM IN THE AFRICAN SPOONBILL (PLATALEA ALBA)

Metabolic bone disease (MBD) was diagnosed in two chicks produced by a captive breeding colony of African spoonbills (Platalea alba). The birds were housed indoor during the winter breeding season and had no access to natural sunlight. When the index cases occurred, the nesting birds and chicks had a mean 25-hydroxyvitamin D (25-OHD) concentration of 9.9 ± 2.7 nmol/L and a mean ionized calcium (iCa) concentration of 0.98 ± 0.12 mmol/L (winter pretreatment). For comparison purposes, serum was collected the following summer; mean 25-OHD was 20.8 ± 3.9 nmol/L and mean iCa was 1.32 ± 0.05 mmol/L (summer). During the following breeding season, ultraviolet B (UVB) lighting was provided to the flock, resulting in a mean 25-OHD of 19.0 ± 5.6 nmol/L and mean iCa of 1.23 ± 0.06 mmol/L (winter treatment 1). Both 25-OHD and iCa were significantly higher compared with winter pretreatment, and 25-OHD was not significantly different from summer, indicating that treatment during the winter months succeeded in increasing 25-OHD levels to summer levels. However, winter treatment 1 and summer iCa were significantly different. During the next breeding season (winter treatment 2), the birds were exposed to a light with higher UVB output. The mean 25-OHD of the flock was 16.5 ± 7.2 nmol/L, and the mean iCa increased to 1.34 ± 0.04 mmol/L. Both were comparable to summer values. Healthy chicks were hatched during both breeding seasons, and no further cases of MBD occurred during the course of the study. Provision of a UVB light source to captive African spoonbills maintained indoors during the winter months can increase 25-OHD and iCa to levels equivalent to those seen in the summer months, when birds have unrestricted access to natural sunlight. UVB lighting is recommended for all breeding spoonbills that do not have access to natural sunlight.

Super pharmacological levels of calcitriol (1,25-(OH)2D3) inhibits mineral deposition and decreases cell proliferation in a strain dependent manner in chicken mesenchymal stem cells undergoing osteogenic differentiation in vitro

The biologically active form of vitamin D₃, calcitriol (1,25-(OH)₂D₃), plays a key role in mineral homeostasis and bone formation and dietary vitamin D₃ deficiency is a major cause of bone disorders in poultry. Supplementary dietary cholecalciferol (25-hydroxyvitamin D, 25-OH), the precursor of calcitriol, is commonly employed to combat this problem; however, dosage must be carefully determined as excess dietary vitamin D can cause toxicity resulting in a decrease in bone calcification, hypercalcinemia and renal failure. Despite much research on the therapeutic administration of dietary vitamin D in humans, the relative sensitivity of avian species to exogenous vitamin D has not been well defined. In order to determine the effects of exogenous 1,25-(OH)₂D₃ during avian osteogenesis, chicken bone marrow-derived mesenchymal stem cells (BM-MSCs) were exposed to varying doses of 1,25-(OH)₂D₃ during in vitro osteogenic differentiation and examined for markers of early proliferation and osteogenic induction. Similar to humans and other mammals, poultry BM-MSCs were found to be highly sensitive to exogenous 1,25-(OH)₂D₃ with super pharmacological levels exerting significant inhibition of mineralization and loss of cell proliferation in vitro. Strain related differences were apparent, with BM-MCSs derived from layers strains showing a higher level of sensitivity to 1,25-(OH)₂D₃ than those from broilers. These data suggest that understanding species and strain specific sensitivities to 1,25-(OH)₂D₃ is important for optimizing bone health in the poultry industry and that use of avian BM-MSCs are a useful tool for examining underlying effects of genetic variation in poultry.

Can feeding the broiler breeder improve chick quality and offspring performance?

The impact of nutrition on the performance of broiler breeders in terms of bodyweight profile, egg production, egg size and shell quality, mortality, fertility and hatchability has been well documented. However, studies on the direct effects of breeder nutrition on subsequent chick quality and offspring performance are limited. The present paper reviews the nutritional factors in broiler breeders that may improve chick quality and progeny performance. Recent research has suggested that the feeding of low crude protein and medium to high energy breeder diets in both rearing and laying period will not only have a positive impact on egg production, egg size, breeder fertility, hatchability and embryonic livability, but also on offspring performance. Improvements include better chick quality, higher chick weight, lower mortality, increased immune responses, enhanced litter quality and broiler growth. Breast-meat yield in the progeny can be improved as the energy to protein ratio increases from the rearing phase to the laying phase, indicating that nutrition of pullets can also affect growth and yields. The effects of maternal diet on offspring performance may depend on the sex of the progeny, with male broilers responding more than female broilers to breeders’ dietary protein and energy concentrations. However, little work has been conducted on the effects of individual amino acids in breeder diets on the subsequent generation. There seems to be some benefits with the use of long-chain poly-unsaturated fats in breeder diets on carcass quality of offspring, but these effects appear inconsistent at this stage. There is substantial evidence that confirms the direct effects of vitamin D and E, and trace minerals, especially in organic form, such as selenium, zinc and manganese, on chick quality and progeny performance. In fact, the impact of breeder nutrition on progeny performance in the field is more likely to be greater under conditions of poor breeder-flock uniformity, low vitamin and trace mineral contents or certain types of stress in the broiler house.

Effects of 25-hydroxycholecalciferol and soy isoflavones supplementation on bone mineralisation of quail

1. The effects of 25-hydroxycholecalciferol (25-OH-D(3)) and soy isoflavones supplementation on performance, carcase recovery, bone mineral density, and tibia ash, Ca, P, and serum vitamin D concentrations and alkaline phosphatase activity in the Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature were evaluated. 2. A total of 270 ten-d-old Japanese quail were randomly assigned to 9 treatment groups, 6 replicates of 5 birds each in a 2 x 3 x 3 factorial arrangement of treatments. Birds were kept in a temperature-controlled room at either 22 degrees C (thermo-neutral) or 34 degrees C (heat stress) for 8 h/d (09:00-17:00 h) and given a basal (control) diet or the basal diet supplemented with one of three levels of 25-OH-D(3) (0, 250 and 500 IU/kg of diet) combined with one of three levels of soy isoflavones (0, 400 and 800 mg/kg of diet). 3. Birds kept at 34 degrees C consumed less feed and gained less weight than control birds. An increase in body weight, feed intake (and improvement in feed efficiency and carcase recovery were found in soy isoflavones and 25-OH-D(3)-supplemented quail reared under heat stress conditions. Bone mineral density, tibia ash, Ca, and P were linearly improved by 25-OH-D(3) and soy isoflavones supplementation in both thermoneutral and heat stress groups. Serum vitamin D levels and alkaline phosphatase activity were improved by 25-OH-D(3) and soy isoflavones supplementation in both thermoneutral and heat stress groups in quail. 4. In conclusion, a combination of 25-OH-D(3) and soy isoflavones supplementation to basal diet significantly improved bone mineralisation in quail.

Calcium metabolism in birds

Calcium is one of the most important plasma constituents in mammals and birds. It provides structural strength and support (bones and eggshell) and plays vital roles in many of the biochemical reactions in the body. The control of calcium metabolism in birds is highly efficient and closely regulated in a number of tissues, primarily parathyroid gland, intestine, kidney, and bone. The hormones with the greatest involvement in calcium regulation in birds are parathyroid hormone, 1,25-dihydroxyvitamin D(3) (calcitriol), and estrogen, with calcitonin playing a minor and uncertain role. The special characteristics of calcium metabolism in birds, mainly associated with egg production, are discussed, along with common clinical disorders secondary to derangements in calcium homeostasis.