Growth performance, digestibility, intestinal morphology, Carcass traits and meat quality of broilers fed marginal nutrients deficiency-diet supplemented with different levels of active Yeast

A total of 216 one-day-old Arbor Acres broiler chicks were randomly distributed among 36 cages of 6 replicates per treatment and 6 birds per cage during 1-38 d of age. A factorial design (2 x 3) was used in which there were two feed rations [standard diet vs. marginal nutrients deficiency-diet (MNDD)] and three Saccharomyces cerevisiae (SC, active yeast) concentrations (0, 0.02 and 0.04%). The results showed that marginal nutrients deficiency-diet significantly decreased growth rate and production index during the experimental period and this accounted for 5.4% for the whole period. The MNDD impaired feed conversion ratio (FCR) during 1-21 d of age, but FCR for the whole period was not affected. Addition of SC at 0.04% significantly improved growth rate and increased organic matter digestibility and apparent ash retention, compared to 0.02% diet. Addition of SC had a significant effect on percentage of gastrointestinal tract and length of villi. Dressing percentage was significantly higher for the group fed on MNDD than those on the standard diet. The increase in the dressing percentage was associated with significantly higher gizzard, gut percentage and length of the intestine. The type of diet, the SC concentration, and the interaction between them had no significant effects on the chemical composition and the physical characteristics of the meat. It could be concluded that SC supplementation to standard- or MNDD improved growth performance of broiler chickens. Hence, feeding MNDD supplemented with either 0.02 or 0.04% SC showed higher growth performance than the standard diet without SC supplementation.