Effects Of Enzyme Complex On Growth Performance And Nutrient Utilization In Broiler Chickens

A 6-week experiment was conducted to investigate the effect of supplementing different enzyme cocktails in corn-soybean-byproduct diets on broiler chickens' growth performance and nutrient utilization. 630 1-day-old Arbor Acre broiler chicks were randomly allocated to 7 experimental groups with 6 replicates. One acted as control group(A) and fed basal diet, another six treated groups were fed the basal diet supplemented with six different enzyme complexes, namely B (RD1), C (RD2), D (RD3), E (RD4), F (RD5), G (RD6), the supplementation level for each enzyme were 0.75Kg/t. At the same time, a metabolic trial was carried out on 42 birds at 27d .The results showed that ADG (average day weight gain) during 0-2Id in all enzyme complex supplementing groups, with the exception of group B, have been improved in some extent (1.34-4.21%). Among those, group G was the best (PO.05). FCR (feed conversion ratio) showed a decreasing tendency (2.78-3.98%) in enzyme supplementing groups, although there was no significant difference between treated group and control. During 22-42d, ADG of group D and group E were the best, which were 6.12% and 5.66% higher than control group(P<0.05 ), respectively. Group D, E and B had better FCR than other groups in this period, they were 5.63%, 5.42% and 5.17% higher than control group respectively (P<0.05) . In the whole experiment period, the ADG of all enzyme cocktails supplementing groups had been improved, among them group E and D was the best, which were increased by 4.39% and 4.24% (P<0.05) ; FCR in group D, E and B were better than other groups, they were decreased by 4.69% , 4.55% and 4.26% in contrast with control(P<0.05).There were no significant difference in broiler chicks carcass weight (% of weight), abdominal fat (% of carcass) and breast weight (% of carcass) between treated group and control (P>0.05) .All enzyme complexes supplementing groups have improved the thigh muscle ratio of birds, but only group D increased 11.34%, significantly (PO.05). With the exception of group B, AME of enzyme supplementing diets have an increasing tendency. However, there is no significantdifference (P>0.05 ); The NPU (net protein utilization) showed the same tendency as the AME, especially in diet F, E and D, which were 7.18%, 6.66% and 5.72% higher than control group respectively.