24-25-dihydroxyvitamin-d-3 and Poultry-Diseases

Studies were conducted to evaluate several cholecalciferol (D3 metabolites: 1,25-dihydroxycholecalciferol [1,25-(OH)2D3], 1,24R,25-trihydroxycholecalciferol [1,24R,25-(OH)3D3], 1 alpha-hydroxy-cholecalciferol (1 alpha-OHD3), 24R,25-dihydroxycholecalciferol [24R,25-(OH)2D3], 1,25-dihydroxy-26,27 hexadeuterium cholecalciferol (1,25-(OH)2-26,27[2H]6D3) and 1,25-dihydroxy-24R-fluorocholecalciferol [1,25-(OH)2-24R-FD3] for their activity in preventing the development of tibial dyschondroplasia in broilers. The basal diet used is low in calcium, high in phosphorus and chlorine and is known to promote a high incidence of tibial dyschondroplasia. The chicks received ultraviolet radiation from fluorescent lights in addition to 1100 ICU/kg (27.5 micrograms/kg) of D3 in the basal diet. Supplementation of the diet with 10 micrograms/kg of all the metabolites except 24R,25-(OH)2D3 significantly lowered the incidence and severity of tibial dyschondroplasia and increased bone ash when compared to birds receiving the basal diet. None of the active D3 metabolites was effective when fed at 0.1 or 1.0 micrograms/kg of diet. Two active compounds tested [1,25-(OH)2D3 and 1,24R,25-(OH)3D3] at 5 micrograms/kg of diet were effective in reducing either the incidence or severity of tibial dyschondroplasia.

Topics: 24,25-Dihydroxyvitamin D 3; Analysis of Variance; Animals; Calcitriol; Calcium; Chickens; Cholecalciferol; Hydroxycholecalciferols; Male; Osteochondrodysplasias; Poultry Diseases; Tibia

Vitamin D-deficient chicken embryos were obtained by feeding laying hens diets in which 3-7 micrograms calcitriol replaced the vitamin D3 supplement. A large proportion of the D-deficient embryos failed to complete the prehatching positional changes required to start pulmonary respiration. For this reason most of them became cyanotic and had subcutaneous edema and hemorrhages in the head and neck and died without hatching. Total as well as leg-bone and muscle weights were significantly lower in the deficient embryos than in the controls and these changes probably explain the inability of the embryos to complete the movements required to place the beak in contact with the air chamber and start pulmonary respiration. The histological study of the tibiae showed decreased mineralization with narrower trabeculae and enlarged osteoid seams; bone resorption at the inner surface was also significantly decreased. The ultrastructural study of parathyroid glands showed increased functional activity reflected by increased number and size of cisternae of rough endoplasmic reticulum. Injection of 10 ng calcitriol, 1 microgram 24,25-(OH)2D3, or 2 micrograms 25OHD3 to deficient embryos on the 14th day of incubation improved hatchability, bone and muscle weights, and both bone mineralization and resorption.

Topics: 24,25-Dihydroxyvitamin D 3; Animals; Bone and Bones; Calcifediol; Calcitriol; Chick Embryo; Dihydroxycholecalciferols; Movement; Muscles; Parathyroid Glands; Poultry Diseases; Vitamin D Deficiency

Experiments have been conducted to obtain information on the cause of tibial dyschondroplasia in chickens. All studies were conducted with corn-soybean meal practical-type diets and chicks from 1 day to 3 or 4 weeks of age. A high calcium and low phosphorus content of the diet and a wide calcium:phosphorus ratio in the diet decrease the incidence of tibial dyschondroplasia in broiler chickens. Increasing the chloride level of the diet increased the incidence of tibial dyschondroplasia. Increasing the magnesium content of the diet decreased tibial dyschondroplasia; however, the effect of magnesium was not as strong as that of calcium. The addition of sodium sulfate to the diet had no effect on the incidence of tibial dyschondroplasia. Five broiler strain crosses were all susceptible, although to a variable extent, to the development of tibial dyschondroplasia, whereas Single Comb White Leghorn chickens did not develop the disease. Male chicks developed tibial dyschondroplasia with a higher incidence than did female chicks. Supplementation of the chickens with 20 ng/day of either 1,25-dihydroxycholecalciferol [1,25(OH)2D3] or 24,25-dihydroxycholecalciferol [24,25(OH)2D3] had no effect on the incidence of tibial dyschondroplasia. J. Nutr . 114: 1001-1013, 1984.

Topics: 24,25-Dihydroxyvitamin D 3; Aging; Animal Feed; Animals; Calcitriol; Calcium; Chickens; Chlorides; Diet; Dihydroxycholecalciferols; Female; Male; Osteochondrodysplasias; Phosphorus; Poultry Diseases; Sex Factors; Sodium; Species Specificity; Tibia