Effectiveness of twenty-five-hydroxycholecalciferol in the prevention of tibial dyschondroplasia in Ross cockerels depends on dietary calcium level

• Published in: Poultry science 2003-11, Vol.82 (11), p.1769-1777
• Main Authors: Ledwaba, M.F, Roberson, K.D
• Format: Article
• Language: English
• Subjects: 25-hydroxycholecalciferol; Animals; ash content; blood serum; body weight; Calcifediol - administration & dosage; calcium; Calcium, Dietary - administration & dosage; Chickens; deficiency diseases; dietary minerals; disease incidence; dosage; dose response; dyschondroplasia; feed conversion; Male; nutrient retention; Osteochondrodysplasias - prevention & control; Osteochondrodysplasias - veterinary; phosphorus; Phosphorus - metabolism; phosphorus retention; Phosphorus, Dietary - administration & dosage; phytic acid; Phytic Acid - metabolism; poultry diseases; Poultry Diseases - prevention & control; poultry feeding; rickets; Tibia; ultraviolet radiation; Ultraviolet Rays; vitamin deficiencies
• ISSN: 0032-5791; 1525-3171
• DOI: 10.1093/ps/82.11.1769

Five experiments were conducted to evaluate the efficacy of 25-hydroxycholecalciferol [25-(OH)D3] to minimize the development of tibial dyschondroplasia (TD) and improve phytate phosphorus retention in Ross cockerels during the starter period. In experiment 1, chicks were fed a TD-inducing (0.67% calcium) diet with or without exposure to ultraviolet light and no supplemental cholecalciferol. Dietary 25-(OH)D3 was added at 0, 10, or 70 microgram/kg for both light treatments. In experiment 2, 25-(OH)D3 was added at 0, 10, 40, or 70 microgram/kg to a TD-inducing diet containing 27.5 microgram/kg added cholecalciferol. Experiment 3 was similar to experiment 2 except a diet marginal (0.85%) in calcium was fed, and cholecalciferol was added at 55 microgram/kg. In experiments 4 and 5, 25-(OH)D3 was added at 0, 18, 36, 54, 72, or 90 microgram/kg to a diet marginal in calcium. Dietary 25-(OH)D3 decreased the incidence of TD similarly at 40 and 70 microgram/kg 25-(OH)D3 and improved phytate phosphorus retention when the TD-inducing diet was fed. The incidence of TD was decreased when 70 microgram/kg 25-(OH)D3 was added to a diet marginal in calcium in experiment 3 only. Phytate phosphorus retention was generally not affected by dietary 25-(OH)D3 when a diet containing marginal calcium, adequate phosphorus, and high cholecalciferol was fed. The effectiveness of 25-(OH)D3 to reduce the incidence of TD in young broilers was higher when the dietary calcium level was below 0.85%. The incidence of TD in Ross cockerels was low (