| Antimicrobial peptides(AMPs)have multidimensional properties including antimicrobial activity,antifungal activity,anti-parasite activity,etc.AMPs more used in the prevention and treatment of mastitis and improve production performance and other aspects of ruminant breeding.However,there are few reports on the effects of rumen fermentation.In order to explore the feasibility of antimicrobial peptides as a new feed additives,this study evaluates the effects of AMPs on the rumen fermentation function in goats,using a single-factor approach with 3 groups(15.53±1.06kg BW,n=6).These included group?(control group),group?(Taikanglibao Group A),and group?(Taikanglibao Group B).Goats in each group were fed a dietary concentrate containing 0;2.0,or 3.0 g AMPs daily for 60 days.All the goats were weighted on days 0,20,40,and 60,prior to morning feeding.Then,each group were randomly selected 4 goats of rumen fluid samples and jugular vein blood testing ruminal pH,the concentration of volatile fatty acids,NH3-N,urea nitrogenat and MCP,the activities of xylanase,pectinase,P-glucosidase,carboxymethyl cellulose,protease,amylase and lipase,and serum growth-related hormone levels during the research and weighed one by one.Results:(1)Effects of AMPs on pH value and the concentration of volatile fatty acids in rumen fluid of goats.AMPs had no observed effect on ruminal pH;the concentration of acetate in group ?was higher than group I in addition to the 60th day,but the difference was not significant(P>0.05);the AMPs-fed groups showed an increase in the concentrations of acetate,propionate and total volatile fatty acids at the other time points(P<0.01or 0.05),but did not show a change in the butyrate and the molar proportion of acetate,butyrate and propionate(P>0.05).Nevertheless,there is a downturn in the molar proportion of acetate,butyrate and propionate.(2)Effects of AMPs on nitrogen metabolism in rumen fluid of goats.Relative to the control group,the group II showed a decrease the concentration of NH3-N(P<0.01or 0.05).On day 60,the group III significantly lower than the control group(P<0.05);the AMPs-fed groups were also lower than the control group at the rest of the time,but the difference was not significant(P>0.05);and the concentration of urea nitrogenat was also decreased in group II on day 60(P<0.05).AMPs had no observed effect on the concentrations of MCP,but AMPs-fed groups were higher than that of the control group and the highest in the group II.(3)Effects of AMPs on enzyme activity in goats.Relative to the control group,supplementation with AMPs significantly increased the enzyme activities of xylanase,pectinase and lipase at both treatment levels(P<0.01or 0.05),the group II was higher than group?;AMPs had no observed effect on carboxymethyl cellulose or protease at either level of supplementation(P>0.05),and did not affect ?-glucosidase and amylase activity at the 2.0g per head per day level(P>0.05),but a decrease was observed in the activiy of ?-glucosidase and amylase at the 3.0g per head per day supplementation level(P<0.01or 0.05).(5)Effects of AMPs on serum growth-related hormone levels and weight in goats.Supplementation with AMPs significantly increased the level of IGF-1?T3 and T4(P<0.01 or 0.05).Relative to the control group,The weight of goat in group II was significantly increased in addition to the 60th day(P<0.05).The AMPs-fed groups were higher than the control group at the other time points,but the difference was not significant(P>0.05),the group II was higher than groupIII.Supplementation with AMPs significantly increased the average daily gain of goats(P<0.01or 0.05).Conclusions:Our results indicate that dietary supplementation with AMPs increased the concentrations of acetate,propionate and total volatile fatty acids,and decreased the concentration of NH3-N,urea nitrogenat,and increased the concentrations of MCP,enzyme activity,and the level of IGF-1,T3,T4 and the average dialy gain,which confirmed that the AMPs can promote the growth of the goats. |
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