Calcium and Phosphorus Retention by Laying Hens Fed Diets Supplemented with Ascorbic Acid and Cholecalciferol

Abstract

This study was designed to assess the influence of supplemental ascorbic acid and cholecalciferol on calcium (Ca) and phosphorus (P) retention in laying hens. Bovan Brown pullets (n=384) aged 12 weeks were randomly assigned to 12 dietary treatment in a 3x4 factorial arrangement of a completely randomised design. Diets were supplemented with three levels of vitamin C at 0, 300 and 600 mg/kg and four levels of cholecalciferol at 0, 1000, 2000 and 3000 IU/kg with feed and water provided ad libitum for 58 weeks. At week 70, four birds per treatment were selected and arranged in metabolic cages for faecal collection. Faecal calcium and phosphorus were determined according to standard procedures while calcium and phosphorus retention were calculated. There were highly significant (p<0.01) variations in Ca and P retention (73.10 and 70.13) in birds on 300 mg/kg ascorbic acid compared with birds on 0 mg/kg (66.92 and 55.82) and 600 mg/kg ascorbic acid (70.55 and 66.43). Also, calcium retention in birds on supplemental cholecalciferol at 3000 IU (81.66) was significantly higher (p<0.01) than 61.23, 76.40 and 61.47 in birds fed supplemental cholecalciferol at 0, 1000 and 2000 IU/kg, respectively. Though, calcium retention in birds on 0 and 2000 IU/kg cholecalciferol were similar (p>0.01), phosphorus retention in birds on 3000 IU/kg cholecalciferol supplementation (77.57) was higher (p<0.01) than in birds on 1000 IU/kg (69.56), 2000 IU/kg (58.71) and 0 IU/kg cholecalciferol (50.65). Interaction of ascorbic acid and cholecalciferol however, was significant (p<0.01) on calcium and phosphorus retention. Sole supplemental ascorbic acid or cholecalciferol and their interaction improved calcium and phosphorus retention in laying hens.