The Effect Of Apidaecin On The Performances And Rumen Microflora Of Hu Sheep

As a new substitute of antibiotics,antimicrobial peptides?AMPs?can resist many kinds of pathogenic microorganisms,improve livestock performance,and improve the economic benefits of breeding industry.The AMPs have been widely used in pig and chicken production.In intensive farming system,high-concentrate diets are often used for livestock fattening production,which have a negative effect on rumen health of ruminants.The purpose of this study was to explore the bacteriostatic effect of a new type of AMPs-Apidaecin and its effect on the growth performance and rumen function of Hu sheep,which intend to provide some reference for Apidaecin as a feed additive for fattening sheep feeding.Effect of Apidaecin on rumen microorganisms in vitroThe apidaecin used in this experiment was provided by Gansu Olymbel Biotechnology Group Co.,Ltd.The minimum inhibitory concentration and minimum inhibitory titer of Apidaecin against E.coli and Salmonella were determined by susceptibility test.In addition three treatments were designed by single factor test,and Apidaecin were added at 0,0.75 mg and 1.5 mg,with 7 replicates in each treatment.Before the experiment,1 g diet was accurately weighed into each glass fermentation flask and with ice water to stops fermentation after 24 hours.Gas and fermentation broth were used to determined rumen pH gas compositions,volatile fatty acid concentration and some microorganisms.The results are as follows:the minimum bacteriostatic concentration for E.coli and Salmonella was 0.625 g/mL,and the lowest antimicrobial titer was 533.33 AU/mL.During 24 h in vitro fermenation,0.75%Apidaecin could significantly increase the concentration of acetate and acetate to propionate ratio in rumen?P<0.05?,and significantly reduce the concentration of propionic acid?P<0.05?.The yield of CH₄ was significantly increased?P<0.05?.There was a tendency to increase Prevotella brevis content?P=0.078?.Effect of compound Apidaecin on performances and rumen microflora of fattening Hu sheepA total of 180 male Hu sheep with 2 months age and 25-30 kg body weight were selected.The experiment was designed by single factor experiment.There were 5 treatments,30 test unit,6 units for each treatment,and 6 sheep for each unit.When Apidaecin were supplied and added to the diet in the form of premixed,they were as follows:control group?no antibiotics and Apidaecin supplemented diet?,100 g/T?basic diet+100 g/T Apidaecin?,200 g/T?basic diet+200 g/T Apidaecin?,400 g/T?basic diet+400 g/T Apidaecin?,800 g/T?basic diet+800 g/T Apidaecin?,respectively.The trial transition period was 14 days,the pre-feeding period was 14 days,and the trial period was 63 days.The results are as follows:1.Feeding Apidaecin significantly increased the average daily gain?ADG?throughout the trail period?P<0.05?.The whole body weight gain increased linearly with the increase of Apidaecin in the feed?P<0.05?;the average daily feed intake?ADFI?and feed efficiency increased with the addition of Apidaecin in the feed and there was a significant linear increase?P<0.05?.2.The addition of Apidaecin in the feed can quadratically increase the number of Selenomonas ruminantium and Fibrobacter succinogenes in the rumen?P<0.05?.And the number of Prevotella brevis changed quadratically?P<0.05?.Meanwhile Apidaecin significantly linear increase the number of Ruminobacter amylophilus and the abundance of the Firmicutes?P<0.05?.The addition of Apidaecin quadratically changed the abundance of the Tenericutes?P<0.05?.The Apidaecin in the feed can significantly increase the proportion of acetate in the rumen and decrease the proportion of propionic acid?P<0.05?.It could significantly reduce the proportion of isobutyric acid in the rumen?P<0.05?.And there is a quadratic exponential relationship between the content of Apidaecin and the isobutyric acid.The proportion of acetate to propionate in the rumen was quadratically increased?P<0.05?.To sum up,Apidaecin not only inhibit E.coli and Salmonella,but also increase the ratio of acetate,reduce the ratio of propionate,increase the ratio of acetate to propionate,and promote acetate production in rumen.Apidaecin can improve the production performance of fattening Hu sheep,regulate its rumen microflora and fermentation.