| The experiment by adding high-activity yeast into daily ration is aimed at studying its effects on production performance, breeding egg quality, hatching performance and serum biochemical parameters of Liangfeng broiler breeders as well as providing reference base for scientific and reasonable application of high-activity yeast in production of Liangfeng broiler breeders.This experiment selects 576 Liangfeng broiler breeders with age of 190 days which have no difference in all production indices and immune indices. They are randomly divided into 6 groups with each group having 96 broiler breeders.4 repetitions are set in each group and each repeats 24 broiler breeders. Group I is the control group with basic ration; for Group Ⅱ, Ⅲ, Ⅳ, Ⅴ and VI,0.015%,0.03%,0.06%,0.12% and 0.24% of high-activity yeast are respectively added based on consistent nutrient level of basic ration. Experimental results are as following:Production performance:added with high-activity yeasts of different levels, laying rates of Group IV are 4.3% higher than control group(P<0.05); egg hatching rates, average egg weights and feed-egg ratios have slightly changed yet without obvious difference (P>0.05).Breeding egg quality:application of high-activity yeasts of different levels has no obvious influence on Haugh unit, egg shape index, eggshell strength, eggshell thickness, relative eggshell weight or relative yolk weight(P>0.05).Hatching performance:application of high-activity yeasts of different levels has no obvious influence on hatching eggs fertilization rate, fertilized egg hatching rate or healthy chick rate(P> 0.05).Serum biochemical parameters:after high-activity yeasts of different levels are added, contents of T-CHO and TC present decreasing tendency, TC contents in Group Ⅲ, Ⅴ, Ⅵ are lower than the control group respectively by 20.4%(P<0.05),21.1%(P<0.01),33.5%(P< 0.01).The contents of TP in serum after high-activity yeasts of different levels are added are on the rise, TP contents in Group Ⅴ、Ⅵ are higher than that of the control group respectively by 12.6%(P<0.05),15.3%(P<0.01); Contents of ALB are on the rise, ALB contents in Group Ⅳ, Ⅵ are higher than that of the control group respectively by 9.1%(P<0.05),10%(P< 0.01); Contents of GLB are on the rise, GLB contents in Group Ⅴ, Ⅵ are higher than that of the control group respectively by 16%(P< 0.05),17.6%(P< 0.05); A/G have slightly changed but the difference is not obvious(P>0.05).Contents of AKP in serum after high-activity yeasts of different levels are added are on the rise, AKP contents in Group Ⅳ、Ⅴ、Ⅵ are higher than that of the control group respectively by 19.7%(P<0.01),22.6%(P<0.01)and 25.6%(P<0.01); Contents of ALT, AST and UA have slightly changed but the difference is not obvious(P>0.05).The following conclusions can be reached through the experiment:1.Application of 0.015%～0.06% high-activity yeasts in daily ration can increase laying rate to a certain degree, but has no obvious influence on egg hatching rates, average egg weights and feed-egg ratios.2.Application of high-activity yeasts in daily ration will not influence breeding egg quality and egg hatching performance.3.Application of high-activity yeasts in daily ration can decrease serum lipid level to a certain degree, and 0.12%～0.24% addition can obviously decrease TC level.4.Application of high-activity yeasts in daily ration can increase protein content in serum.5.Application of 0.06%～0.24%high-activity yeasts in daily ration can obviously enhance the level of AKP and has no obvious influence on ALT, AST and UA. |
