| Popis: |
The study investigated the effect of inclusion levels and withdrawal periods of Tetracin on growth performance, carcass trait and occurrence of residues in meat type chickens raised in a tropical environment. Tetracin® a feed grade antibiotic was administered at 0, 50, 100, 150 and 200mg/kg of feed (starter and finisher diets) with observation of different withdrawal periods (0, 7 and 15 days each) for 6 weeks using a 3x5 factorial layout. One hundred and fifty (150) two weeks old broiler chicks (Anak strain) were randomly divided into five treatments of thirty birds each and three replicates of ten birds. The broilers were fed between 2-4 weeks of age on the starter diet and 4-8 weeks of age on finisher diets, while antibiotic withdrawal was practiced at 15, 7 and 0 day respectively for each inclusion level. Performance (feed intake, weight gain and feed: gain ratio) was monitored while six broilers per treatment were used for carcass and organ evaluation. At the end of feeding trial, microbial assay method was used to detect antibiotic residues on samples from breast, thigh, kidney and liver from two birds per treatment. Data on performance and carcass evaluation were analysed using one-way analysis of variance and significant means separated at 5% level of probability. The final body weight (FBW), total body weight gain (TBWG), total feed intake (TFI), plucked weight (PW), eviscerated weight (EW) and dressing percentage of birds increased progressively (P |
