Abstract   

    A total of 480 day-old Fayoumi chicks were randomly selected and divided into four groups of 120 chicks each. The chicks in each group were further sub divided into 3 replicates giving 40 chicks to each replicate. The treatments included feed supplementation with TM-200, Tylan Premix and Reotin F upto 5^th week of age during winter (Phase I) and summer (Phase 11). The average body weight gain during Phase 1 (November-December) was significantly (P< 0.05) increased in all supplemented groups whereas highest weight gain was obtained consequent to supplementation with Tylan Premix. The average feed consumption and mol1ality was significantly higher (P<0.05) in non supplemented control group. During -Phase II (May-June) average body weight gain was significantly higher (P<0.05) in supplemented group as compared with control group. There was no significant difference in average feed consumption and mortality among all the four groups. The study provided evidence that the supplementation of feed with dietary antibiotics particularly with Tylan Premix was efficacious during winter season but these effects were reduced under spell of summer season irrespective of nature of antibiotics

Key words: Supplementation, Antibiotics, Fayoumi Chicks, Body weight gains, Feed Consumption, Mortality, Feed Conversion