Growth Performance, Carcass Yield, and Immune Competence of Broiler Chickens as Influenced by Dietary Supplemental Zinc Sources and Levels

摘要

This study was conducted to determine the effect of sources and levels of zinc (Zn) on growth performance, carcass characteristics, and immunocompetence of broilers. A 6-week (0–6 weeks of age) feeding trial was conducted as per 3 × 4 factorial design involving three Zn sources (zinc propionate—ZnP, zinc oxide—ZnO and zinc sulfate—ZnS) each with four levels of Zn (40, 60, 80, and 100 mg/kg) during starting (0–3 weeks) and finishing (4–6 weeks) phase in a standard broiler diet. Overall body weight gain, feed intake, feed conversion ratio, and percent Zn retention in broilers from 0 to 6 weeks were not differed significantly due to the interaction of different sources and levels of Zn. Growth traits were non-significant due to the main effect of Zn level. Percent Zn retention was decreased due to increase in Zn levels (L effect, P < 0.001; Q effect-non-significant) among different groups. The humoral (HA titre to-SRBC) and cellular (foot pad index (FPI) to phytohaemagglutinin-P) immune response did not differ significantly due to main effect of Zn sources and interaction effect of Zn sources and levels. However, HA titre to SRBC was maximum (P < 0.05) at 80 mg Zn/kg diet and FPI to PHA-P was maximum (P < 0.05) at 60 mg Zn/kg diet. The L effect of Zn level was non-significant for HA titre and FPI. The Q effect of Zn level was significant at P < 0.05 and P < 0.01 for HA titre and FPI, respectively.