Effect Of Eucommia Leaves Extract As Additive On Growth Performance And Antioxidant Functions And Meat Quality In AA Broiler

This experiment is conducted to investigate the effects of different levels of Eucommia leaves extract on growth performance, immunity, meat quality, antioxidant functions in AA broiler. The study will provide the theoretical basis for applications of Eucommia leaves extract in poultry breeding.Design and grouping of the experiments: 275 AA broilers with 1-day-old were randomly divided into five treatment groups, with 5 replicates each group, 11 chickens each replicate. The control group was fed basic diets, and four Eucommia leaves extract preparation groups were fed basic diets supplemented with 0.05%, 0.10%, 0.15% and0.20% Eucommia leaves extract respectively. The trial lasted for 42 days.Experiment Ⅰ, To investigate the effects of Eucommia leaves extract on growth performance and immunity in AA chicken. The results showed that: 1) Growth performance, compared with control group, dietary supplemented with Eucommia leaves extract increased ADG and the feed conversion ratio, but no difference were found about the ADFI among all groups. 2) Immunity, dietary supplemented with 0.15% Eucommia leaves extract increased the concentration of Ig G by 23.06% on day 21, and diets supplemented with 0.05%, 0.15% and 0.20% Eucommia leaves extract increased the concentration of Ig M by 118.89%、73.33% and 71.11%（P<0.05） on day 42. 3) antioxidant index: comparing with the control, Eucommia leaves extract by 0.15% significantly increased the activity of serum SOD and T-AOC, but declined the concentration of MDA by 27.46%（P>0.05） at 42 d. However, serum GSH-Px activity of all treatment groups were increased significantly（P<0.05）. The activity of SOD and GSH-Px in muscle of all treatment groups were increased significantly, but MDA contents in muscle were decreased significantly comparing with the control group.Experiment Ⅱ, This experiment is conducted to investigate the effects of different levels of Eucommia leaves extract on slaughter performance and meat quality in AA broiler.The results were as follows: 1) Slaughter performance, compared with, no difference was noticed about the slaughter performance between all treatment groups and the control group. 2) meat quality, Dietary supplemented with 0.15% Eucommia leaves extract increased the contents of ether extract, but did not affect the contents of moisture, crude protein and ash. the shear force values of 0.15% Eucommia leaves extract group were higher but the drip loss were lower by 20.86%（P>0.05） than those of control group. The a* value of breast muscle in 0.15% and 0.20% groups were increased by 30.12% and17.39%（P<0.05） comparing with the control group, but the b* value of the pectoral muscles in all treatment groups were decreased significantly. 3) Fatty acid content:comparing with the control group, the contents of linoleic（C18:2 n-6）, peanut acid（C20:0）,α-linolenic acid（C18:3 n-3） in 0.15% group were improved, but the contents of γ-linolenic acid（C18:3 n-6） was decreased by 24.85%（P<0.05）. But SFA contents were decreased by7.56%（P<0.05）. Moreover, the contents of USFA, EFA, P/S and n-6value were increased.Experiment Ⅲ, To investigate the effects of Eucommia leaves extract on blood biochemical indexes and the relevance between blood biochemical parameters and slaughter performance, immunity performance and meat quality in AA chicken. The results were as follows, 1) blood biochemical indicators, compared with control group, diets supplemented with Eucommia leaves extract increased significantly the blood sugar, but,the content of serum urea nitrogen in Eucommia leaves extract by 0.05% and 0.10% were decreased significantly. 2) Correlation: there exists a certain correlation between slaughter rate and total protein（R²=0.838）, Serum BUN content has a certain negatively correlation with eviscerated rate（R²=0.829）, Thymus index has some negatively correlation with total protein（R²=0.810）. Moreover, there exists a certain correlation between spleen index and serum T₃（R²=0.965）, Pectoral muscle p H value has some positively correlation with total serum protein and T₄ contents（R²=0.906,0.778）, but the shear force has negative correlation with serum T₄ contents（R²=0.916）. Moreover, L* value has positive correlation with serum GLU（R²=0.817）, but the drip loss has negative correlation with the contents of serum albumin（R²=0.930）.These results showed that dietary supplementation with Eucommia leaves extract by0.15% enhanced growth performance, antioxidant and immunity, improved meat quality and flavor of AA broilers. Moreover, there exists a certain correlation between blood biochemical indicators and immune performance and meat quality, which indicated that blood biochemical indicators may reflect the change of immune performance and meat quality of AA broiler.