| Two experiments were conducted to investigate the synergistic effect and related mechanism of probiotics and enzyme preparation on the effect of production performance of yellow broiler. On the basis of the effects which probiotics and enzyme preparation on the growth performance, nutrient utilization and serum biochemical parameters of yellow broilers, further studies were taken to investigate the effects and the intrinsic link of probiotics and enzyme preparation on slaughter performance, intestinal villi structure and immune function of yellow broilers, and compared with antibiotic feed additives, and to clarify the synergistic mechanism of probiotic and enzyme preparations from multi-level and multi-angle.Experiment Ⅰ:Effects of Probiotics and Enzyme Preparation on Growth Performance, Nutrient Utilization and Serum Biochemical Parameters of Yellow BroilersTo evaluate the effects of probiotics and enzyme preparation on growth performance, nutrient utilization and serum biochemical parameters of yellow broilers,675of healthy5-day-old female yellow broilers with the same weight were randomly selected and allocated to5groups,5replicates in each group and27broilers in each replicate. The diets were fed between5and53days of age. The control group (Ⅰ) was provided with the basal diet, the test groups (Ⅱ、Ⅲ、Ⅳ、Ⅴ) was fed a basal diet which added25g/t probiotics,150g/t multi-enzyme preparation,25g/t probiotics+150g/t multi-enzyme preparation and300g/t colistin sulphate respectively. Results showed that the test group Ⅳ got the highest ADG of the whole trial period, and compared to control group Ⅰ and test Group Ⅴ was increased by4.22%(P<0.05) and2.12%(P>0.05) respectively. And there was no significant difference on ADFI and F/G of the whole period among each group (P>0.05), but there was a trend that the synergy of probiotics and enzyme preparation increased the ADFI and reduced the F/G of the whole trial period (P>0.05); The test group Ⅳ got the highest TME, and compared with control group Ⅰ and test Group Ⅴ was increased by11.29%(P<0.01) and6.89%(P<0.05) respectively. And there was no significant difference on DM metabolizability and ture protein metabolizability among each group (P>0.05), Crude fiber metabolizability of test group Ⅲ was significantly higher than the group Ⅰ、Ⅱ、 Ⅴ (P<0.01) and the group Ⅳ (P<0.05); The test group Ⅳ improved blood biochemical and hormonal indicators in varying degrees, and showed the trend better than the other groups. In general, probiotics and enzyme preparation had a good synergistic effect in improving the growth performance and nutrient utilization of yellow broilers, and it was superior to antibiotic feed additives in some extent.Experiment II:Effects of Probiotics and Enzyme Preparation on Slaughter Performance, Intestinal Villi Structure and Immune Function of Yellow BroilersFor further studying the synergitic mechanism of the probiotics and enzyme preparation and comparing to the effect of the antibiotic feed additives, in this study,10broilers(2broilers in each replicate) which close to the average weight of the group were randomly selected from the Experiment I (group Ⅰ、Ⅱ、Ⅲ、Ⅳ、 Ⅴ) to carry out the slaughtering experiment, and to investigate the slaughter performance, intestinal villi structure and immune function indications. Results showed that the test group Ⅳ got the highest slaughter rate, and compared to control group I and test Group V was increased by0.75%(P>0.05) and0.79%(P>0.05) respectively. Test group IV’s percentage of eviscerated yield compared with control group I’s was increased by5.80%(PO.01), and it had no significant difference with test Group V (P>0.05). And also there was no significant difference on percentage of breast muscle, leg muscle, lean meat and abdominal fat among each group (P>0.05); Antibiotic, probiotics and enzyme preparation and their synergy all can improve the duodenal, jejunal and ileal villus morphology development in different degrees; And there was also no significant difference on Index of thymus, bursa of fabricius and spleen among each group (P>0.05). The test group Ⅳ got the highest density of TP and ALB, and its density of GLO at a high level, the test group IV also had appropriate A/G. The density of FT3of group I and group II were significantly higher than the test group V (PO.05), and whereas the density of FT4of group V was significantly higher than the group I and group Ⅱ (p<0.05), the density of FT3and FT4of group Ⅳ was appropriate. Group I and group II had the same FT3/FT4, and it significantly higher than the test group IV (P<0.05) and the test group V (P<0.01). In general, each additive group had different effects on yellow broilers, but the synergy of probiotics and enzyme preparation demonstrated certain advantages. |
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