Effects Of Compound Antimicrobial Peptides "Taikanglibao" On The Community Structure And The Number Of Common Ciliates Population In The Rumen Of Goats

In recent years,the antimicrobial peptides(AMPs)have received attention due to its broad spectrum activity,speed of action and a low propensity for the development of bacterial resistance.As a new type of feed additive,it has been used in pigs,poultry and other animals,but research on AMPs as alternatives for feed additive in ruminant nutrition is limited and inconclusive.This study investigated the effects of compound antimicrobial peptides“Taikanglibao” on the community structure and number of common ciliates population in the rumen of goats by using MiSeq sequencing technology and Real-time PCR.To provide a theoretical basis for the ruminant feeding that the compound antimicrobial peptides“taikanglibao”as feed additives in ruminant animal.Twenty-four male goats[4-month-old,(16.17±0.72)kg] were randomly divided into 4groups,with six goats each group.Control group: group I-normal concentrate group(300 g concentrate [per head per day]),III-double concentrate group(600 g concentrate),AMPs group: group II-normal concentrate and antimicrobial peptide group(300 g concentrate + 3.0g AMPs),and IV-double concentrate and antimicrobial peptide group(600 g concentrate +3.0 g AMPs),continuous feeding of 60 d.Rumen fluid samples were collected on days 0,20 and 60,prior to morning feeding;Three goats were selected from each treatment group for sampling(50 mL/goat).And then the total DNA were extraced for amplification 18 S rRNA(V547F-V4R),sequencing by MiSeq Illumina250,and the number of common ciliates in different groups was compared by Real-time PCR.Test results:(1)Polyplastron(40.07%~65.59%)and Ophryoscolex(9.9%~52.09%)was the most abundant ciliate genera in all samples.(2)The Alpha diversity index were elevated in the AMP-supplemented groups(II 、 IV),especially on day 60,but no significant differences(P > 0.05).The indexes of group III(double concentrate)was lower than that of group I(normal concentrate),but no significant differences(P > 0.05).(3)Compared with the control groups(I and III),Ophryoscolex appeared to increase in the AMP-supplemented groups,Polyplastron,Entodinium,and Isotricha appeared to decrease in the AMP-supplemented groups,although a significant difference were only apparent with normal concentrate(P<0.05),double feed group(IV compared with III)showed no significant difference(P > 0.05).Moreover,no differences in Polyplastron,Ophryoscolex,and Isotricha were evident between groups I(normal concentrate)and III(double concentrate).(4)The totalnumber of ciliates showed no significant changes between groups(P > 0.05);the number of Ophryoscolex caudatus was increased significantly in the AMP-supplemented groups(P<0.01).Compared with I group(normal concentrate),the number of Entodinium caudatum was increased significantly in group III(double concentrate)(P < 0.01).In addition,in the whole test period,the number of Isotricha prostoma was increased with time,the number of Diploplastron affine was decreased with time,the number of Polyplastron multivesiculatum and Ophryoscolex purkynjei were increased with time in Ⅰand Ⅱgroups,the number of Ophryoscolex caudatus was increased with time in Ⅱand Ⅳgroups,the number of Entodinium simplex and Entodinium caudatum were increased with time in Ⅲand Ⅳ groups.Conclusion: Composite antimicrobial peptides“taikanglibao” can increase the diversity of rumen ciliate trend,the relative content of Ophryoscolex,decrease the relative content of Polyplastron,Entodinium,and Isotricha,but the effect is weaker in double concentrate;The addition of “taikanglibao” at two concentrate levels significantly increased the number Ophryoscolex caudatus,and Ophryoscolex and Ophryoscolex caudatus are closely related to rumen digestion and degradation fibers.Indicated that the composite antimicrobial peptides“taikanglibao” can promote some the degradation of fiber genus or species growth,to improve the growth performance.In addition,The effect of double concentrate on ciliate population structure was not statistically significant,but the number of Entodinium caudatum increased significantly.The addition of “taikanglibao” can enhance the influence of concentrate on ciliate community structure,and further reduce the relative content of fiber degradation.