Effects Of Antibacterial Peptide CC34 Yeast Culture On Rumen Development,Gastrointestinal Flora And Immune Performance Of Lambs

In order to investigate the role of antibacterial peptide CC34 yeast culture in alleviating the stress and nutritional regulation of early-weaning lambs,a single-factor test design was used in this test.Twenty-four 9.64 ± 0.84 kg(mean ± SD)healthy twenty-four-day-old male lambs(small-tailed Han Sheep × northeast fine wool sheep)were assigned to three groups with 8 replicates.Lambs were fed a basal diet(CON,control)or the basal diet supplemented with 2 g/kg of the Pichia yeast culture containing the antimicrobial peptide CC34(CC34)or the basic diet supplemented with 2 g/kg of the Pichia yeast culture(PY)for a 38-d period(8 days trial period).Three sheep(nine in total)were randomly selected from each group at 14 days and 28 days of the experimental period for slaughter to collect samples.The growth performance,apparent digestibility,blood cytokines,and gastrointestinal development of lambs were determined to investigate the effect of antibacterial peptide CC34 yeast culture on early weaning lambs,to provide important basic data for the systematic evaluation of antimicrobial peptide functional characteristics and to reduce the use of antibiotics in livestock and poultry breeding,and to provide a certain theoretical reference value for the development of antibacterial peptides as functional additives for humans and animals in the near future.The experimental results were showed as follows:(1)Throughout the trial period,there was no significant difference in ADFI,ADG,and F: G between the groups(P > 0.05).As the lamb grows,the levels of IL-6,TNF-? and TGF-? in the serum gradually decrease.In the 14 days of the experiment,compared with the CON group,the addition of the antibacterial peptide CC34 yeast culture increased the content of TGF-?(P < 0.05)and decreased the content of TNF-?(P < 0.05).During the 28-day test period,the proportion of lambs' heels to live weight in the CC34 group was significantly lower than that in the CON group(P < 0.05).Compared with the CON group,antibacterial peptide CC34 yeast culture supplementation not only increased the apparent digestibility of Ca(P < 0.05),but also tended to increase the apparent digestibility of NDF(P = 0.0624),However,the apparent digestibility of various nutritional components of lamb supplemented with antibacterial peptide CC34 yeast culture was not significantly different from that of PY supplementation(P > 0.05).(2)Compared with CON treatment,supplemented with antibacterial peptide CC34 yeast culture throughout the test period can increase the content of ammoniacal nitrogen and acetic acid(P < 0.05)in the rumen,increase the relative expression level of Claudin-1 gene in rumen epithelialium of lambs(P < 0.05),and promote the rumen dorsal and rumen peritoneal papilla heights of weaned lambs(P < 0.05),and reduce the thickness of the stratum corneum(P < 0.05);at the same time,the rumen weight and rumen weight percentage of lambs supplemented with antibacterial peptide CC34 yeast culture were highest at 28 days in the experimental period(P < 0.05).(3)The supplementation of antibacterial peptides CC34 and PY had no significant effect on the rumen and cecum bacterial hilum level of the lamb with the CON group(P > 0.05),but at the bacterial genus level,the content of Vibrio succinate in the rumen fluid of the lamb supplemented with the antibacterial peptide CC34 yeast culture was significantly higher than that of the CON group at the 28 day test(P < 0.05).In conclusion,the supplementation of antibacterial peptide CC34 yeast culture in the diet has not significantly improved the growth performance and cecum flora diversity and structure of lambs,but it has effectively promoted rumen development and enhanced its fermentation and immune performance.