Abstract:
This study was conducted to evaluate the using ofthree levels of dry yeast (0.1,0.2,and 0.3%)respectively , Neomycin and control groups on broiler on performance and immune responses. Hundred and five unsexed day old Aberker strain was an average weight of 43 grams were subjected to 43-days experimental period. The chicks were distributed randomly into (5)groups with( 3) replicates each 7chicks per replicates .Treatments groups (A)represent control,(B) Neomycin and C,E,Dcontaining 0.1%,0.2% and 0.3% dry yeast (sacchromycescereviase) respectively. Result showed thatchicksfed 0.3% dry yeast(s.c) had higher significantly (p<0.05) body weight gain(BWG) at end of experiment and best feed conversion ratio (FCR) (1.8). There is no significant differences in feed intake (FI) among all treatments .Chicks fed 0.3% yeast compared to- Neomycin ,0.1% and 0.2%(s.c) groups had a lower abdominal fat and high carcass yield . Belong immune response chicks were fed yeast (0.1%,0.2%,0.3%) showed no significant difference among treatments groups after using of (IBD-D78) vaccine regarding antibodies titer of vaccination but when used yeast 0.3%there is a high antibodies titer different between the treatments neomycin and control group When applied (0.1% 0.2% and 0.3%)yeast respectively had high antibodies titer of vaccine NDV in both readings (18days -43days of age) of vaccination programme .In conclusion in this study regarding to the results obtained indicated that supplementary yeast 0.3% could improve performance values in body weight gain ,feed conversion ratio and highly rate of carcass dressing. In immune response chicks at 18days where recorded highly titer antibodies in group treated by 0.3% yeast .
