PSA-Nutrition: Vitamin/Minerals and Miscellaneous Nutrition

A floor pen study was conducted to determine the efficacy of vitamin D source and level on performance and bone mineralization of broilers fed dietary treatments for six weeks. Dietary treatments included: 1) Basal diet supplemented with NRC recommended levels of vitamin D3 (200,000 ICU/ton); 2) Basal plus 2.5 million ICU (MICU) D3 /ton; 3) basal plus 2.5 MICU D3/ton plus 62.5 mg Hy-D/ton; 4) basal diet plus 5 MICU D3 /ton diet; and 5) basal plus 62.5 mg Hy-D/ton diet. Diets were fed from day 1 to 42, and nutrient concentrations were adjusted at the end of week 3 according to NRC recommendations. Four replicate pens of 20 chicks were fed each treatment from day 1 to 21. On day 21, 6 chicks from each pen were removed for sampling, leaving 4 replicate pens of 14 chicks from day 21 to 42. Compared with chicks fed diet 1, chicks fed all other treatments consumed more feed and gained more weight (P < 0.05) at both weeks 3 and 6. Feed intake and body weight gain were similar (P > 0.05) for chicks fed treatments 2 4 at both weeks 3 and 6. Feed conversion was not affected (P > 0.05) by dietary treatments at either week 3 or 6. Compared with chicks fed diet 1, chicks fed all other treatments had a higher (P < 0.05) percent tibia ash at week 3, whereas at week 6, chicks fed diets 1 and 5 had a lower (P < 0.05) percent tibia ash compared with other dietary treatments. However, on an absolute bone ash weight basis (mg bone ash), bone ash was not affected (P > 0.05) by dietary treatments at either week 3 or 6. Bone breaking strength was also not affected (P > 0.05) by dietary treatments at either week 3 or 6. Results indicate that supplemental vitamin D3 above NRC recommendations was effective in improving chick performance and bone mineralization, and 62.5 mg Hy-D/ton feed was as effective as industry vitamin D3 levels in improving chick performance.