Effects of Compound Probiotics on Performance,Intestinal Microflora, Antioxidant Indices and Immune Function of Broilers

This experiment was conducted to investigate the effects of compound probiotics on the performance,intestinal microflora,antioxidant indices and immune function of broilers.Two hundred and forty 1-day-old famale broiler chickens were randomly divided into 4 groups with 3 replicates in each group and 20 chickens per replicate.The chickens in the control group(group Ⅰ) were fed a basal diet,and those in other groups(groups Ⅱ,Ⅲ and Ⅳ) were fed the basal diet and drank the water with compound probiotics A and its adjuvant B in different levels.From 6 days of age,compound probiotics A of 2.0‰ diets was supplemented twice a week(half of 2.0‰ of weekly feed intake at a time),and adjuvant B was supplemented for successive 3 days(once a day) after immunization at 7,14 and 21 days of age,respectively,and the supplemental level of adjuvant B was 0.5‰,1.0‰ and 2.0‰ of daily feed intake of broilers,respectively.The pre-trial period lasted for 5 days,and the experiment lasted for 37 days.Performance,intestinal microflora,antioxidant and immune indices were determined in different periods.The results showed as follows: 1) in every test period,compared with the control group,the average daily gain of broilers in group Ⅱ was significantly higher(P0.05),and feed/gain(F/G) was significantly lower(P0.05);except F/G at 7 to 14 days and 15 to 21 days,the average daily gain and F/G of broilers in group Ⅱ were significantly better than those in the other groups(P0.05).2) The number of cecal Lactobacillus of broilers aged 14 and 28 days in groups Ⅱ and Ⅲ was significantly higher than that in the control group(P0.05);the number of cecal E.coli of broilers aged 14 days in groups Ⅱ and Ⅲ was significantly lower than that in the control group(P0.05);for 28-day-old broilers,only the number of cecal E.coli in group Ⅱ was significantly lower than that in the control group(P0.05).3) The total antioxidant capacity in plasma of broilers aged 21,28 and 35 days in groups Ⅱ and Ⅲ was significantly higher than that in the control group(P0.05),but there was no significant difference between group Ⅱ and group Ⅲ(P0.05).4) The spleen index of broilers aged 14 and 42 days in group Ⅳ was significantly higher than that in the control group(P0.05);the bursa of Fabricius index of broilers aged 14,28 and 42 days in group Ⅲ was higher than that in the control group(P0.05).In conclusion,the supplementation of 2.0‰ compound probiotics A and 0.5‰ adjuvant B can improve performance,gain a better cecal micro-ecosystem,and enhance the antioxidant function of broilers.Meanwhile,the supplementation of compound probiotics and its adjuvant can improve the immune function of broilers to some degree.