Effects Of Lactic Acid Bacteria On Growth Performance And Immune Capability Of Juvenile Rabbits

In this study, we investigated the effect of lactic acid bacteria on growth performance, abattage performance, quality of meat, blood biochemical indexes, immunity indexes and immunoglobulin contents of juvenile rabbits. And the reasons why lactic acid bacteria promoted the growth of juvenile rabbits and kept its healthy were discussed. The experiment was designed using single-factor randomized trial. Forty male and forty female rabbits with similar weight,43days old, were randomly divided into4groups, which were control group, test Ⅰ group, test Ⅱ group, test Ⅲ group and test Ⅳ group. Each group has4replicates with4rabbits. The control group was fed basal diet with physiological saline and the test groups were fed basal diet supplemented with104,107,1010and1013cfu/ml lactic acid bacteria, respectively. The trial lasted for7days for adaptation and60days for test (starter1-30d, finisher31-60d). Four rabbits each group were slaughtered for the indicators measurement in30th day and in60th day during the test. The results showed as follows:(1)Significant effect of lactic acid bacteria was observed on average daily gain and feed to gain ration. In the test Ⅱ group of the c stage and the test Ⅱ group and test Ⅲ group of the whole stage, the average daily gain increased by15.29%,13.09%and12.07%respectively in comparison to control group (P<0.05). While the gain ration in test Ⅱ group of the1st stage and2nd, the Ⅱ group and test Ⅲ group of the whole stage was significantly lower than control group by7.17%,10.49,10.04%and10.05%respectively (P<0.05). However, there was no significant effect of lactic acid bacteria on the daily feed intake (P>0.05).(2) Lactic acid bacteria increased the percentage of half-eviscerated yield and percentage of eviscerated yield, but the difference was not significant (P>0.05).(3) Lactic acid bacteria could improve the quality of meat. In the1st stage, the crude protein in test Ⅱ group increased by6.78%(P<0.05); in the2nd stage, the crude protein in test Ⅱ group and test Ⅲ group increased by7.24%and6.89%respectively (P<0.05).The crude ash in test Ⅱ group and test Ⅲ group of the1st stage increased by5.38%and7.38%respectively (P<0.05);the crude ash in test Ⅱ group increased by6.96%(P<0.05).But no significant effect was observed on the moisture or crude fat in meat(P>0.05). (4) Significant effect of lactic acid bacteria was observed on the blood biochemical indexes. In the1st stage, the contents of SUN of test Ⅱ group and test Ⅲ group reduced by10.32%and9.33%respectively (P<0.05); In the2nd stage, the contents of SUN of test Ⅲ group reduced by12.12%(P<0.05).The contents of HDL-C in test Ⅱ group of the1st stage increased by21.37%(P<0.05). In the2nd stage, the contents of GLO of test Ⅲ group increased by14.30%(P<0.05); A/G in test Ⅱ group and test Ⅲ group reduced by9.12%and11.68%respectively(P<0.05). There was no significant effect of lactic acid bacteria on the contents of TP and ALB (P>0.05).(5) Lactic acid bacteria could improve the immune capability of juvenile rabbits. In the1st stage, the spleen index and the contents of slgA in test Ⅱ group was higher than control group (P<0.05); the thymus index in test Ⅱ group, test Ⅲ group and test Ⅳ group were significantly improved in comparison to control group (P<0.05). In the2nd stage, the liver index, the contents of slgA and IgG were higher than control group(P<0.05); the thymus index in test Ⅰ group, test Ⅱ group and test Ⅲ group were significantly improved in comparison to control group (P<0.05).From the results above, it could be concluded that lactic acid bacteria can promote the growth, improve the quality of meat and the immune capability of juvenile rabbits. In our experiment, the appropriate supplemental level of lactic acid bacteria was107cfu/ml.