| Crude enzyme preparations from anaerobic fungi were developed and the enzyme activities and their effects on the growth performance, gut microfiora and viscosity of gut digesta of broilers were investigated. The paper was described in three sections .In the first section, crude enzyme preparations were processed by concentrating 5-fold and 10-fold and using rice grain hull powder, rice bran and wheat bran, respectively. Xylanase activities in crude enzyme preparations were determined to obtain enzyme gain rate after processing with different combinations. The result indicated that the combination with 5-fold concentration and rice grain hull powder as carrier produced a relatively high gain rate of xylanase, with the value as 85.07%.In the second section, the optimal temperature and pH of the xylanase in the crude enzyme preparations and the degradation of wheat powder by the crude enzyme preparation were investigated. Results indicated that the optimal temperature of xylanase in the crude enzyme preparations was 50C and its optimal pH was 6.0. Wheat powder (10 g) was degraded by crude enzyme preparations by in vitro incubation. As compared with the control (without enzyme preparations), the reducing sugar content in supernatants in treatments of 0.50g, 1.00g, 1.50g and 2.00g crude enzyme preparations increased by 10.78%, 20.18%, 25.85%and 26.96%, respectively. The viscosity in the supernatants in treatments with 1.00g, 1.50g and 2.00g decreased by 7.09%, 9.45%and 8.66% as compared with the control.In the third section, the effects of supplementation with crude enzyme preparations to the wheat-based diet on the growth performances of broilers were investigated. 450 broilers were randomly divided into 5 groups each with 5 replicates and 18 broilers in each replicate. Groups 1, 2 and 3 were supplemented with crude enzyme preparations of anaerobic fungi at 0.2%, 0.4% and 0.8%, respectively. Group 4 was supplemented with 0.1% of commercial enzymes and group 5 was served as the control. The results showed that during the age 0 d to 21 d average daily weight gain in groups 1, 2, 3 and 4 were significantly higher than that in control group ( P< 0. 05 ) , and increased by 19.67%, 20.68%, 23.69% and 24.85%, respectively. The feed intake in each treatment group is slightly lower than that of thecontrol group, but no significant differences was observed( P > 0. 05 ). As compared with the control group, the feed conversion rate in group 1,2,3 and 4 decreased by 16.94%, 19.67%, 21.31% and 19.67%, respectively (P< 0. 05) . From the age 22 d to 42 d, the average daily weight gain of broilers in groupl, 2, 3 and 4 increased by 22.35%, 25.38%, 20.95% and 14.59% as compared with the control group ( P< 0. 05 ). And the feed intake in each treatment group is slightly higher than that of the control group, but no significant difference was observed (P > 0. 05 ). The feed conversion rates in groupl, 2, 3 and 4 were significantly lower than that in the control, decreasing by 14.18%, 15.30%, 14.55% and 8.21%, respectively (P < 0. 05 ). During the whole growth stage, the average daily weight gain in group 1, 2, 3 and 4 increased by 21.50%, 23.83%, 21.82% and 17.84% as compared with the control group ( P< 0. 05 ) . The feed intakes in treatment groups were all slightly higher than that in the control group (P > 0. 05 ) . The feed conversion rates in group 1, 2, 3 and 4 decreased by 14.94%, 16.18%, 16.18% and 12.03%, respectively, as compared with that in the control group ( P< 0. 05 ) .The numbers of ?coli and lactic acid bacteria in boilers' gut and the viscosity of gut digesta were also determined, at age of 21-days, numbers of E.coli in jejunum of broilers in group 2 and 4 were significantly lower than that in the control group ( P< 0. 05 ) , but no significant difference was observed between group 1 and 3 and the control ( P > 0. 05 ) . Numbers of lactic acid bacteria (LAB) in jejunum in treatment groups were slightly higher than that in the contrast group. Numbers of E.coli in ileum of broilers in group 2 and 4 we...
|
PDF Full Text Request