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One Alpha-hydroxycholecalciferol Improves Growth Performance, Tibia Quality, and Meat Color of Broilers Fed Calcium- and Phosphorus-Deficient Diets.

An experiment was conducted to evaluate the effects of one alpha-hydroxycholecalciferol (1α-OH D3) on growth performance, tibia quality, and skin and meat color in broilers fed calcium (Ca)- and phosphorus (P)-deficient corn-soybean meal diets. A total of 288 male Ross broilers, at 21 days of age, were randomly assigned to three treatments with eight cages per treatment. Three levels of 1α-OH D3 (0, 5, and 10 μg/kg) were added to a basal diet (0.50% Ca, 0.13% non-phytate phosphorus (NPP), and 0.35% total phosphorus (tP)) without vitamin D3. As a result of this study, the addition of 1α-OH D3 increased body weight gain (p<0.001), feed intake (p = 0.007), feed efficiency (p<0.001), tibia weight (p = 0.002), length (p<0.001), breaking-strength (p = 0.012), ash (p<0.001), Ca (p<0.001), and P content (p = 0.004). Dietary 1α-OH D3 enhanced breast meat yellowness (p = 0.015) and the length and weight of the small intestine of the broilers. Moreover, 1α-OH D3 decreased serum Ca concentration (p = 0.074) and breast meat redness (p = 0.010). These results indicate that the 1α-OH D3 improves growth, tibia quality, and meat color in broilers fed Ca- and P-deficient corn-soybean meal diets.

Effects of fermentation products of Cordyceps militaris on growth performance and bone mineralization of broiler chicks

The present study aimed to evaluate the effects of fermentation products of Cordyceps militaris (FPCM) on growth performance and tibia mineralization of broiler chicks. A total of 240 one-day-old female Ross 308 broilers were allotted into four treatments with six cages of 10 chicks each. Four diets were the control diet supplemented with 0, 1, 2 and 4 g/kg of FPCM, respectively. Compared with the control, supplementation of 1 g/kg FPCM improved body weight gain of broilers from 22 to 42 days of age and from 1 to 42 days of age (P < 0.05); 4 g/kg of FPCM enhanced the feed intake of 22- to 42-day-old and 1- to 42-day-old chicks (P < 0.05). Addition of 2 g/kg FPCM increased tibia calcium (Ca) content of broilers at 21 and 42 days (P < 0.01). FPCM did not affect serum biochemical parameters (P > 0.05). These data indicate that FPCM had positive effects on growth performance of broiler chicks and the optimal dietary FPCM level was 1 g/kg in chicks from 1 to 42 days of age.

Relative biological value of 1α-hydroxycholecalciferol to 25-hydroxycholecalciferol in broiler chicken diets

&NA; This study was conducted to evaluate the relative biological value (RBV) of 1&agr;‐hydroxycholecalciferol (1&agr;‐OH‐D3) to 25‐hydroxycholecalciferol (25‐OH‐D3) in one‐ to 21‐day‐old broiler chickens fed calcium (Ca)‐ and phosphorus (P)‐deficient diets. On the d of hatch, 450 male Ross 308 broiler chickens were weighed and randomly allotted to 9 treatments with 5 replicates of 10 birds per replicate. The basal diet contained 0.50% Ca and 0.25% non‐phytate phosphorus (NPP) but was not supplemented with cholecalciferol (vitamin D3). The levels of Ca and NPP in basal diets were lower than those recommended by NRC (1994). 25‐OH‐D3 was fed at zero, 1.25, 2.5, 5.0, and 10.0 &mgr;g/kg, and 1&agr;‐OH‐D3 was fed at 0.625, 1.25, 2.5, and 5.0 &mgr;g/kg. The RBV of 1&agr;‐OH‐D3 to 25‐OH‐D3 based on vitamin D intake was determined by the slope ratio method. Results showed that 25‐OH‐D3 or 1&agr;‐OH‐D3 improved the growth performance and decreased the mortality in one‐ to 21‐day‐old broilers. A linear relationship was observed between the level of 25‐OH‐D3 or 1&agr;‐OH‐D3 and mineralization of the femur, tibia, or metatarsus. The RBV of 1&agr;‐OH‐D3 to 25‐OH‐D3 were 234, 253, and 202% when the weight, ash weight, and Ca percentage of femur were used as criteria. The corresponding RBV of 1&agr;‐OH‐D3 to 25‐OH‐D3 were 232 to 263% and 245 to 267%, respectively, when tibia and metatarsus mineralization were used as criteria. These data indicate that when directly feeding a hormonally active form of vitamin D as 1&agr;‐OH‐D3 proportionally less is needed than when using the precursor (25‐OH‐D3) in diets deficient in Ca and P.

Effects of calcium to non-phytate phosphorus ratio and different sources of vitamin D on growth performance and bone mineralization in broiler chickens

ABSTRACT - A 7 × 2 factorial experiment was designed to test the effects of calcium (Ca) to non-phytate phosphorus (NPP) ratio (1.14, 1.43, 1.71, 2.00, 2.29, 2.57, and 2.86) and different sources of vitamin D (1α-hydroxycholecalciferol (1α-OH-D3) and 25-hydroxycholecalciferol (25-OH-D3)) on growth performance and bone mineralization in 1- to 42-d-old broiler chickens. On the day of hatch, 700 female Ross 308 broilers were weighed and randomly assigned to 14 treatments with five stainless steel cages of 10 birds each. Dietary Ca levels were 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0 g kg−1 and the NPP content was 3.5 g kg−1. The dose of 1α-OH-D3 or 25-OH-D3 was 5 µg kg−1. Diets were not supplemented with cholecalciferol (vitamin D3). Results showed that the Ca to NPP ratio, vitamin D source, and their interaction affected body weight gain (BWG), feed intake (FI), feed efficiency (FE), and carcass and breast yields, as well as tibia weight and length and ash weight in broiler chickens from 1 to 42 d of age. Broilers fed 1α-OH-D3 had higher BWG and FI as well as tibia breaking strength, weight, length, diameter, and ash weight than birds fed 25-OH-D3 at 42 d of age. The Ca to NPP ratio had a quadratic effect on BWG, FI, mortality, as well as tibia breaking strength, weight, length, ash weight, and ash and P contents in 42-d-old broilers. Broiler chickens at 42 d of age obtain optimal growth performance and bone mineralization at the Ca to NPP ratio of 2.32 when 1α-OH-D3 or 25-OH-D3 are used as the vitamin D source.

Comparison of the Growth and Mineralization of the Femur, Tibia, and Metatarsus of Broiler Chicks

This study aimed at comparing the growth and mineralization of the femur, tibia, and metatarsus of male and female broiler chicks. On the day of hatch, 100 male and 100 female Ross 308 broiler chicks were transferred stainless cages with 10 birds per cage. On d 7, 14, 21, 28, 35, and 42, five males and five females were sacrificed and their femur, tibia, and metatarsus were collected. Results showed that the tibia was the heaviest and the longest and contained the highest content of ash and calcium (Ca) among the three leg bones. The femur had the greatest diameter. The weight, length, diameter, and ash weight of the femur, tibia, and metatarsus linearly increased with age. The ash, Ca, and phosphorus (P) content in the femur and the tibia quadratically increased with age; by contrast, these parameters in the metatarsus linearly increased with age. The bones grew faster in 1 to 21 d of age. The weight, diameter, and ash weight of the three bones of males were higher than those of females. The Ca to P ratio of the three bones (femur, tibia, and metatarsus) was approximately 2.0:1. These data indicate that there are differences in bone growth and mineralization among the femur, tibia, and metatarsus of male or female broiler chicks.

Evaluation of Relative Bioavailability of 25-Hydroxycholecalciferol to Cholecalciferol for Broiler Chickens

This study was conducted to evaluate the relative bioavailability (RBV) of 25-hydroxycholecalciferol (25-OH-D3) to cholecalciferol (vitamin D3) in 1- to 21-d-old broiler chickens fed with calcium (Ca)- and phosphorus (P)-deficient diets. On the day of hatch, 450 female Ross 308 broiler chickens were assigned to nine treatments, with five replicates of ten birds each. The basal diet contained 0.50% Ca and 0.25% non-phytate phosphorus (NPP) and was not supplemented with vitamin D. Vitamin D3 was fed at 0, 2.5, 5.0, 10.0, and 20.0 μg/kg, and 25-OH-D3 was fed at 1.25, 2.5, 5.0, and 10.0 μg/kg. The RBV of 25-OH-D3 was determined using vitamin D3 as the standard source by the slope ratio method. Vitamin D3 and 25-OH-D3 intake was used as the independent variable for regression analysis. The linear relationships between the level of vitamin D3 or 25-OH-D3 and body weight gain (BWG) and the weight, length, ash weight, and the percentage of ash, Ca, and P in femur, tibia, and metatarsus of broiler chickens were observed. Using BWG as the criterion, the RBV value of 25-OH-D3 to vitamin D3 was 1.85. Using the mineralization of the femur, tibia, and metatarsus as criteria, the RBV of 25-OH-D3 to vitamin D3 ranged from 1.82 to 2.45, 1.86 to 2.52, and 1.65 to 2.05, respectively. These data indicate that 25-OH-D3 is approximately 2.03 times as active as vitamin D3 in promoting growth performance and bone mineralization in broiler chicken diets.

Accumulation of melanin in the peritoneum causes black abdomens in broilers

A suspected case of localized visceral hyperpigmentation was described for a breed of broiler in China. Using optical microscopy, the accumulation of pigments in the abdominal skin and visceral peritoneum was observed. Electron microscopy was used to further study the ultrastructure of the pigmented peritoneum, and pigment granules resembling melanosomes at different stages were found, and melanocytes were present in this tissue. Infrared spectroscopy was used to analyze the physical-chemical properties of pigments extracted from these broilers. Using synthetic melanin as a reference and the melanin from the peritoneum of Silkie fowls as a control, the pigments in the peritonea of these broilers were found to be melanin, and it had a chemical structure similar to that of melanin from the Silkie fowl peritoneum. In this way, the black abdomens of these broilers were found to have been caused by accumulation of melanin produced by melanocytes in visceral peritonea.

Age, phosphorus, and 25-hydroxycholecalciferol regulate mRNA expression of vitamin D receptor and sodium-phosphate cotransporter in the small intestine of broiler chickens

ABSTRACT Four experiments were conducted in this study. Experiment 1 was carried out to examine mRNA expressions of nuclear vitamin D receptor (nVDR), membrane vitamin D receptor (mVDR), and type IIb sodium‐phosphate cotransporter (NaPi‐IIb) in the small intestine of broiler chickens. Experiments 2, 3, and 4 were implemented to evaluate effects of age, non‐phytate phosphorus (NPP), and 25‐hydroxycholecalciferol (25‐OH‐D3) on mRNA expressions of nVDR, mVDR, and NaPi‐IIb in the duodenum of chickens. Results showed that mRNA expression levels of nVDR and NaPi‐IIb were highest in the duodenum of 21‐day‐old broilers, lower in the jejunum, and lowest in the ileum. By contrast, no differences in mRNA expression levels of mVDR were detected among the duodenum, jejunum, and ileum. Age quadratically affected mRNA expressions of nVDR, mVDR, and NaPi‐IIb in the duodenum and 25‐hydroxylase in the liver of 7‐ to 42‐day‐old broilers, with the highest levels observed at 21 d of age. By contrast, age linearly decreased mRNA expression level of 1&agr;‐hydroxylase in kidneys. Dietary NPP levels quadratically affected mRNA expression levels of nVDR and mVDR in the duodenum and 25‐hydroxylase in the liver of 21‐day‐old broilers. The highest mRNA expression levels of nVDR and mVDR and lowest mRNA level of 25‐hydroxylase were observed at 0.55% NPP. mRNA expression level of NaPi‐IIb linearly declined when dietary NPP levels increased from 0.25 to 0.65%. Addition of 12.5 &mgr;g/kg of 25‐OH‐D3 increased mRNA expression level of 1&agr;‐hydroxylase in kidneys and those of nVDR, mVDR, and NaPi‐IIb in the duodenum of broilers compared with birds fed the diet without 25‐OH‐D3. These data indicate that mRNA expressions of nVDR and NaPi‐IIb are highest in the duodenum, and the greatest mRNA levels of nVDR, mVDR, and NaPi‐IIb are observed at 21 d of age. Dietary NPP levels quadratically increase mRNA expressions of nVDR and mVDR but linearly decrease NaPi‐IIb mRNA level. 25‐OH‐D3 up‐regulates the above gene transcription.

Effects of Non-phytate Phosphorus and 1a-Hydroxycholecalciferol on Growth Performance, Bone Mineralization, and Carcass Traits of Broiler Chickens

This study evaluated the effects of dietary non-phytate phosphorus (NPP) and 1a-hydroxycholecalciferol (1a-OH-D3) on the growth performance, bone mineralization, and carcass traits of 1- to 21-day-old broiler chickens. On the day of hatch, 600 male Ross 308 chicks were weighed and randomly assigned to 12 treatments, with five cages of 10 birds each. A 6 × 2 factorial arrangement was applied, consisting of 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, or 0.45% NPP and 0 or 5 μg/kg of 1a-OH-D3. The basal diet contained 0.52% calcium (Ca) and was not supplemented with vitamin D3. Dietary NPP levels significantly affected growth performance and tibia mineralization (except width) of broilers; by contrast, meat yield and organ relative weight were not influenced by NPP. The inclusion of 1a-OH-D3 improved growth performance, tibia mineralization, and carcass and breast yield, whereas it decreased the relative weights of the liver, heart, and kidney. A significant interaction between NPP and 1a-OH-D3 was observed for body weight gain (BWG), feed efficiency (FE), mortality, serum Ca and P levels, tibia breaking-strength, ash weight, and Ca content, as well as breast yield and heart relative weight. These results suggest that broilers fed with 5 μg of 1a-OH-D3 per kg of diet obtain optimal growth performance and tibia mineralization when dietary NPP level was 0.30% and the analyzed Ca to NPP ratio was 1.97.

1α-Hydroxycholecalciferol improves the growth performance and up-regulates the mRNA expression of vitamin D receptor in the small intestine and kidney of broiler chickens

ABSTRACT 1&agr;‐Hydroxycholecalciferol (1&agr;‐OH‐D3) is a vitamin D derivative. The objective of this study was to evaluate the effects of 1&agr;‐OH‐D3 on the growth and the mRNA expression of vitamin D receptor (VDR) in the small intestine and kidney of chickens. A total of 240 males of one‐day‐old Ross 308 broilers was randomly assigned to 4 treatments with 5 replicates of 12 birds per replicate. Three levels of 1&agr;‐OH‐D3 (1.25, 2.5, and 5 &mgr;g/kg) were added to a basal diet containing 0.50% calcium (Ca), 0.25% non‐phytate phosphorus (NPP), and without supplemental cholecalciferol (vitamin D3). The control diet contained 1.00% Ca, 0.45% NPP, and 25 &mgr;g/kg cholecalciferol. Dietary 1&agr;‐OH‐D3 levels linearly improved the average daily feed intake (ADFI), average daily gain (ADG), femur and tibia mineralization, and plasma Ca concentration, and retained Ca and total phosphorus (tP) amounts in broilers from 1 to 21 d of age (P < 0.05). In addition, 1&agr;‐OH‐D3 also linearly up‐regulated the mRNA expression levels of VDR in the duodenum as well as those of VDR and sodium‐phosphate cotransporter NaPi‐IIa and NaPi‐IIc in the kidney of broilers (P < 0.05). However, 1&agr;‐OH‐D3 did not affect the mRNA levels of 25‐hydroxylase in the liver or NaPi‐IIb in the duodenum (P > 0.05). No differences were observed in the ADFI, ADG, bone length, plasma mineral concentration, retained tP amount, or the mRNA levels of the above genes (except for VDR in the kidney) between the birds fed the diet with 5 &mgr;g/kg 1&agr;‐OH‐D3 and the birds fed the control diet (P > 0.05). By contrast, the weight, ash weight, ash percentage, and Ca percentage of the bone, retained Ca amount, and the mRNA level of VDR in the kidney were lower in the birds fed the diet with 5 &mgr;g/kg 1&agr;‐OH‐D3 than in the birds fed the control diet (P < 0.05). These data indicate that 1&agr;‐OH‐D3 up‐regulates the gene expression of VDR in the small intestine and kidney at the transcriptional level, thereby improving the growth performance and bone mineralization of broiler chickens from 1 to 21 d of age.