Effects Of Dietary Supplementation With Bacteriophages On Growth Performance,Meat Quality,Serum Immunity,Antioxidant Activity,Intestinal Development,and Bacterial Flora In Meat Rabbits

This experiment was conducted to investigate the effects of dietary bacteriophages supplementation on growth performance,meat quality,serum immunity and antioxidant,intestinal development and microflora of meat rabbits.A total of 800 weaned New Zealand rabbits with similar body weight at 28 days of age were randomly divided into5 groups with 10 replicates per group and 16 rabbits per replicate.The five groups were fed the following diets:basal diet,basal diet+250 mg/kg pnagus mix preparation,basal diet+500 mg/kg pnagus mix preparation,basal diet+750 mg/kg pnagus mix preparation,basal diet+200 g/t Emlamycin（4%）+1000 g/t aureomycin（15%）.The pnagus mixture was composed of pnagus Escherichia coli,Clostridium Weigi and Salmonella,and the total titer was 1×10⁹ PFU/g.The pre-test period lasted for 7 days and the experimental period lasted for 42 days.The results showed that:（1）Compared with the control group,the average daily feed intake of meat rabbits in 500 mg/kg and 750 mg/kg bacteriophages groups and antibiotic groups was significantly increased（P<0.05）,and the ratio of feed to gain was significantly decreased（P<0.05）.There was no significant diference in average daily feed intake between 500 mg/kg and 750 mg/kg bacteriophages groups and antibiotic groups（P>0.05）.（2）Compared with the control group,the diarrhea rate and mortality of meat rabbits in 500 mg/kg and 750 mg/kg bacteriophages groups and antibiotic groups were significantly decreased（P<0.05）,and there were no significant differences in diarrhea rate and mortality of meat rabbits in 500 mg/kg and 750 mg/kg bacteriophages groups and antibiotic groups（P>0.05）.（3）Compared with the control group,the live weight before slaughter and eviscope weight of meat rabbits in 500 mg/kg,750 mg/kg bacteriophages and antibiotic groups were significantly increased（P<0.05）,and the semi-eviscope weight of meat rabbits in 750 mg/kg bacteriophages and antibiotic groups was significantly increased（P<0.05）.There was no significant difference between the bacteriophages groups（250 mg/kg,500 mg/kg,750 mg/kg）and antibiotic groups in the rate of semi-evisceration（P>0.05）.（4）Compared with the control group,the muscle yellowness in all pnagus groups was significantly increased（P<0.05）,and the muscle PH_{45 min} in 500 mg/kg,750 mg/kg pnagus and antibiotic groups was significantly increased（P<0.05）.（5）Compared with the control group,the drip loss rate of muscle in 500 mg/kg bacteriophages group and antibiotic group was significantly increased（P<0.05）,and there was no significant difference in drip loss rate between 500 mg/kg bacteriophages group and antibiotic group（P>0.05）.（6）Compared with the control group,the contents of Ig A,Ig E and Ig M in serum of meat rabbits in bacteriophages group and antibiotic group were significantly decreased（P<0.05）,and the contents of Ig A,Ig E and Ig M in serum of meat rabbits in bacteriophages group were significantly higher than those in antibiotic group（P<0.05）.（7）Compared with the control group,the serum LPS content of meat rabbits in 250 mg/kg and 750mg/kg bacteriophages groups was significantly increased（P<0.05）,and the serum LPS content of meat rabbits in antibiotic group was significantly lower than that in all bacteriophages groups（P<0.05）.（8）Compared with the control group,the contents of CAT in serum of meat rabbits in 500 mg/kg bacteriophages group were significantly increased（P<0.05）,and the contents of MDA in serum of meat rabbits in antibiotic group were significantly increased（P<0.05）.（9）Compared with the control group,the villus height of duodenum and ileum of meat rabbits in 250 mg/kg bacteriophages group and antibiotic group was significantly decreased（P<0.05）,and the villus height of duodenum and jejunum of meat rabbits in 750 mg/kg bacteriophages group was significantly higher than that in antibiotic group（P<0.05）.（10）Compared with the control group,the ileum crypt depth of meat rabbits in 250 mg/kg bacteriophages group and antibiotic group was significantly increased（P<0.05）,and the ileum crypt depth of meat rabbits in antibiotic group was significantly higher than that in 750 mg/kg bacteriophages group（P<0.05）.（11）Compared with the control group,the ratio of villus height to crypt depth of duodenum,jejunum and ileum of meat rabbits in 250mg/kg and 500 mg/kg bacteriophages groups and antibiotic groups was significantly decreased（P<0.05）,and the ratio of villus height to crypt depth of duodenum,jejunum and ileum of meat rabbits in 750 mg/kg bacteriophages group was significantly higher than that in antibiotic group（P<0.05）.（12）Compared with the control group,the Chao1 observed index ofαdiversity of microbe in cecum of meat rabbits in 500 mg/kg bacteriophages group decreased significantly（P<0.05）.The Chao1 and observed indexes ofαdiversity of cecal microbe of meat rabbits in 500 mg/kg bacteriophages group and antibiotic group were not significantly different（P>0.05）.（13）Compared with the control group,the abundance of Synergistetes in cecum microorganisms of meat rabbits in 500 mg/kg bacteriophages group was significantly increased（P<0.05）,and the abundance of Clostridia in cecum microorganisms of meat rabbits in 500 mg/kg bacteriophages group was significantly decreased（P<0.05）.The cecal microbe Erysipelotrichaceae in 750 mg/kg bacteriophage group and antibiotic group was significantly increased（P<0.05）.And the cecal microbe Erysipelotrichaceae of meat rabbits in antibiotic group was significantly higher than that in 500 mg/kg bacteriophages group（P<0.05）.In conclusion,the growth performance,meat quality,serum immunity and antioxidant capacity of meat rabbits can be improved significantly when supplemented with 500 mg/kg and 750 mg/kg bacteriophages mixed preparation,but there is no adverse effect on intestinal development and cecum microorganisms,and the effect of750 mg/kg bacteriophages mixed preparation is better.