Effect of vitamin D status on the activity of carbonic anhydrase in chicken epiphysis and kidney

The effects of 1a(OH)D3 individually or in combination with phytase, and different levels of cholecalciferol on performance, tibia criteria, and plasma minerals of Japanese quails

The aim of studywas to compare efficacy of 1-α(OH)D3 alone or in combination with phytase and 1-α(OH)D3 in combination of phytase and different concentration of cholecalciferol on performance, tibia parameters, andplasma minerals of quails fed Ca-P deficient diet. A total of 280 mixed sex 5-d-old quails were allocated to 7 treatments with 5 replicates. The vitamin supplement which incorporated to basal diet did not contain cholecalciferol. The dietary treatments were as follows: Ca-P deficient diet (basal diet); basal diet + 500 FTU phytase/kg of diet; basal diet + phytase + 5 μg of 1-α(OH)D3 kg-1 of diet;basal diet + phytase + 5 μg of 1-α(OH)D3 and 250, 500, 750 and 1,000 IU of cholecalciferol kg-1of diet. The highest final body weight and the best feed conversion ratioobtained in the group supplemented with 1,000 IU cholecalciferol kg-1 of diet (p < 0.05). Supplementation of 1-α(OH)D3 alone or in combination with phytase and phytase and different concentration of cholecalciferol could improve tibia parameters (p < 0.05). In conclusion, supplementation of 1-α(OH)D3 alone to Ca-P deficient diet could maximize tibia mineralization, whereas it couldn't maximize performance, performance criteria were maximized by supplementation of 1,000 IU cholecalciferol kg-1 of diet.

Investigation of different levels of cholecalciferol and its metabolite in calcium and phosphorus deficient diets on growth performance, tibia bone ash and development of tibial dyschondroplasia in broilers

This experiment was conducted to examine the effects of 1-α(OH)D3 alone or in combination with different levels of cholecalciferol on performance, and tibia parameters of one-d–old male broilers fed a tibial dyschondroplasia (TD)-inducing diet. A total of three hundred male broilers were randomly allocated to 5 treatment groups with 4 replicates. The dietary treatments consisted of TD inducing diet, TD inducing diet supplemented with 5 μg per kg of 1-α(OH)D3; TD inducing diet supplemented with 5 μg per kg of 1-α(OH)D3 and 1,500; 3,000 or 5,000 IU cholecalciferol kg-1 of diet. At 42 d of age, broiler chickens fed diets containing 1-α(OH)D3 and 1,500 IU cholecalciferol kg-1 of diet had higher body weight (p < 0.05). In the complete experimental period the best FCR and the highest daily weight gain were obtained in broilers supplemented with 1-α(OH)D3 and 1,500 IU cholecalciferol kg-1 of diet. Broilers supplemented with 1-α(OH)D3 and 1,500 IU cholecalciferol kg-1 of diet had significantly lower incidence and severity of TD in comparison with other groups. In conclusion, the results indicated that the supplementation of 1-α(OH)D3 in combination of 1,500 IU cholecalciferol kg-1 of diet could maximize tibia bone ash, performance and prevent TD in broilers fed TD inducing diet.

Evaluation of one-alpha-hydroxy-cholecalciferol alone or in combination with cholecalciferol in Ca-P deficiency diets on development of tibial dyschondroplasia in broiler chickens

This experiment was conducted to determine whether dietary cholecalciferol will alleviate a calcium and phosphorous (Ca—P) deficiency when one-alpha-hydroxy-cholecalciferol, 1α(OH)D₃, is supplemented, and to determine the effects of adequate and inadequate Ca—P when 1α(OH)D₃ is supplemented and vitamin D₃ is adequate. A total of 144 one-d-old broiler chicks (Ross 308) were allocated to 3 treatments. The dietary treatments were as follows: treatment A, adequate Ca—P + cholecalciferol + 5 μg/kg 1α(OH)D₃; treatment B, inadequate Ca—P + cholecalciferol + 5 μg/kg 1α(OH)D₃; treatment C, inadequate Ca—P + 5 μg/kg 1α(OH)D₃. All diets were mixed with 500 FTU/kg of phytase, and cholecalciferol was provided in 5,000 IU/kg except for treatment C that fed diets without vitamin D_3. The Ca—P levels in the adequate diets were 0.90% Ca, 0.66% total phosphorus (tP); 0.75% Ca, 0.59% tP; 0.69% Ca, 0.54% tP for the starter, grower and finisher periods. At d 42 of age, broilers were inspected for incidence and severity of tibial dyschondroplasia (TD). The results showed that inadequate Ca—P supplementation with cholecalciferol significantly decreased the incidence of TD, score and tibia ash compared with broilers fed the same diet in the absence of cholecalciferol (P < 0.05). The broilers fed inadequate Ca—P diets with cholecalciferol were unable to achieve the same tibia ash and incidence of TD as those fed Ca—P adequate diets (P < 0.05). In conclusion, this trial suggests that broilers fed an inadequate Ca—P diet with 1α(OH)D₃ and adequate level of cholecalciferol are unable to sufficient bone formation. There was no indication that 1α(OH)D₃ in the absence of cholecalciferol was effective in reducing TD whereas it could improve tibia ash.

Differential mRNA expression profiles in proximal tibia of aged rats in response to ovariectomy and low-Ca diet

Both ovariectomized animals and animals fed with Ca-depleted diets are commonly used in vivo models for the investigation of osteoporosis-related bone loss. The present study aimed to study the genomic responses of bone in aged female rats to ovariectomy and dietary Ca deficiency in these models. Aged (11 months old) Sprague-Dawley rats were subjected to bilateral ovariectomy or sham-operation and fed with diets containing different dietary Ca content (LCD, 0.1% Ca or HCD, 1.2% Ca) for 12 weeks. Serum and urine were collected for biochemical marker measurement, and tibias were collected for bone mineral density (BMD) analysis by pQCT as well as for gene expression analysis by real-time PCR. Ovariectomy increased serum N-telopeptides of bone type I collagen (NTx) levels in aged rats fed with HCD (P<0.05). In addition, ovariectomy reduced BMD and predicted bone strength of tibial proximal metaphysis in aged rats fed with either LCD or HCD. Dietary Ca deficiency did not alter serum bone-specific alkaline phosphatase (BAP) or NTx levels, but induced a loss of BMD at tibia proximal metaphysis in aged rats. Ovariectomy promoted the mRNA expression of alpha-1 type I collagen (COL), osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa B ligand (RANKL); and inhibited the mRNA expression of cathepsin K and matrix metalloproteinase-9 (MMP-9) in the proximal tibia of aged rats. Low-Ca diet significantly up-regulated the mRNA expression of COL, core binding factor I (Cbfa1), OPG and carbonic anhydrase II (CAII) in proximal tibia of aged rats. Our study revealed that the genomic responses of bone in proximal tibia to ovariectomy and dietary Ca deficiency were different. The bone loss induced by ovariectomy appears to be mediated primarily by an increase in RANKL mRNA expression; whereas the induction by dietary Ca restriction might be mediated by the induction of carbonic anhydrase II expression.

Effects of dietary calcium and 1,25-dihydroxycholecalciferol on the development of tibial dyschondroplasia in broilers during the starter and grower periods

Two experiments were conducted to determine whether dietary 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] can prevent tibial dyschondroplasia in broiler chickens throughout the growing period when withdrawn from the grower diet. The birds were reared in floor pens with pine shavings to 6 wk in Experiment 1 and 5 wk of age in Experiment 2. Calcium was fed at .65 or 1.00% and 1,25-(OH)2D3 was fed at 0 or 5 micrograms/kg to 3 wk of age. Half the birds consuming 1,25-(OH)2D3 were then fed 0 microgram/kg until the end of the experiments. The higher level of calcium decreased the incidences of tibial dyschondroplasia and severe lesions and increased bone ash. Dietary 1,25-(OH)2D3 increased bone ash at both levels of calcium at 3 wk and the end of the experiments when supplemented for the duration of the studies. When 1,25-(OH)2D3 was fed, tibial dyschondroplasia was reduced in Experiment 2 only at 3 wk. Tibial dyschondroplasia was decreased at 5 wk in Experiment 2 when .65% calcium was fed with or without 1,25-(OH)2D3 from 3 to 5 wk of age. There were no treatment effects on plasma calcium, dialyzable phosphorus, or 25-hydroxycholecalciferol. Plasma 1,25-(OH)2D3 was decreased at 3 and 5 wk in Experiment 2 when 1.00% calcium was fed. The results of Experiment 2 suggest that 1,25-(OH)2D3 can prevent tibial dyschondroplasia caused by inadequate calcium when fed for only 3 wk. The bone ash observed when 1.00% dietary calcium is fed is equal to that obtained when 5 micrograms/kg 1,25-(OH)2D3 is fed with .65% calcium for the entire growout period.