| In order to study the effects of antibacterial peptide on weaned piglets,200Landrace×Yordshire weaned piglets were divided into5groups randomly,5duplicates per group and8piglets per duplicate, and groups1-5were treated as follows:(1)basal diet;(2)basal diet+150mg/kg aureomycin;(3)basal diet+150mg/kg cecropins;(4)basal diet+300mg/kg cecropins;(5)basal diet+450mg/kg cecropins. The trial last for28days. The samples were collected and growth performances, microbe population in intestinal tract, serum hormone levels and blood biochemical parameters of piglets on the28th day were determined, the results showed that:1. The effects of different treatments on growth performances of pigletsThe average daily gain (ADG) in group2-5were greater than control group by6.7%(P>0.05),8.26%(P<0.05),11.54%(P<0.05) and8.63%(P<0.05) respectively, and the ADG in cecropins groups were higher than aureomycin group by1.42%(P>0.05),4.49%(P>0.05) and1.77%(P>0.05) respectively. The average daily feed intake (ADFI) in groups2-5were greater than control group by5.68%(P>0.05),4.67%(P>0.05),5.84%(P>0.05) and4.15%(P>0.05) respectively. The F/G in groups2-5were lower than control group by1.14%(P>0.05),3.41%(P>0.05),5.68%(P>0.05) and4.55%(P>0.05) respectively, and the F/G in cecropins groups were lower than aureomycin group by2.30%(P>0.05),4.60%(P>0.05) and3.45%(P>0.05) respectively. The diarrhea incidence in groups2-5were lower than control group by27.62%(P>0.05),28.18%(P>0.05),31.00%(P>0.05),27.85%(P>0.05)(1-14d)and15.24%(P>0.05),15.24%(P>0.05),18.03%(P>0.05),14.31%(P>0.05)(15-28d) respectively.2. The effects of different treatments on microbe population in intestinal tract of pigletsThe number of E. coli in group2-5were decreased by16.30%(P<0.05),26.06%(P<0.05),28.47%(P<0.05) and21.23%(P<0.05), and the number of E. coli in cecropins groups were lower than aureomycin group by11.66%(P<0.05),14.54% (P<0.05) and5.89%(P>0.05) respectively in14d. The number of E. coli in cecropins groups were lower than control group by13.11%(P<0.05),16.27%(P<0.05) and12.36%(P<0.05) respectively in28d. The number of lactobacillus in groups2-5were decreased by11.24%(P<0.05),4.11%(P>0.05),6.49%(P>0.05),4.32%(P>0.05) and16.51%(P<0.05),8.47%(P>0.05),9.63%(P>0.05),8.36%(P>0.05) respectively in14and28d. The number of bifidobacterium in cecropins groups were lower than control group by14.63%(P<0.05),15.89%(P<0.05) and14.88%(P<0.05) respectively.3. The effects of different treatments on serum hormone levels of pigletsThe level of serum GH in group3and4were higher than control group by0.54%(P>0.05and4.86%(P>0.05) respectively. The level of T3in aureomycin group were lower than control group by17.78%(P>0.05), while in cecropins groups were increased by32.59%(P<0.05),39.26%(P<0.05) and34.07%(P<0.05) respectively, and higher than aureomycin group by61.26%(P<0.05),69.37%(P<0.05) and63.06%(P<0.05) respectively. The level of T4in cecropins groups were higher than control group by9.19%(P>0.05),13.99%(P>0.05) and10.32%(P>0.05) respectively. The level of INS in cecropins groups were higher than group1and2by20.55%(P<0.05),27.35%(P<0.05),23.79%(P<0.05) and22.13%(P <0.05),29.02%(P<0.05),25.41%(P<0.05) respectively. The level of COR in groups2-5were decreased by7.07%(P>0.05),13.25%(P<0.05),14.58%(P<0.05) and13.78%(P<0.05) respectively.4. The effects of different treatments on blood biochemical parameters of pigletsThe level of TP in cecropins groups were increased by11.96%(P>0.05),19.34%(P>0.05) and11.09%(P>0.05) respectively. The content of UN in groups2-5were decreased by1.72%(P>0.05),5.38%(P>0.05),5.81%(P>0.05) and4.95%(P>0.05) respectively. The content of TC in cecropins groups were lower than group1and2by20.82%(P<0.05),23.21%(P<0.05),19.80%(P<0.05) and16.25%(P<0.05),18.77%(P<0.05),15.16%(P<0.05) respectively. The content of TG and HDL-C in groups2-5were increased by4.55%(P>0.05),2.27%(P> 0.05),9.09%(P>0.05),9.09%(P>0.05) and1.52%(P>0.05),9.09%(P>0.05),19.70%(P<0.05),10.61%(P>0.05) respectively. The content of LDL-C in groups2-5were decreased by3.80%(P>0.05),10.33%(P<0.05),11.41%(P<0.05) and8.70%(P<0.05) respectively.In conclusion, antibacterial peptide in ideal level could improve the growth performances and microbial community structure in intestinal tract of weaned piglets, it could also increased the level of serum hormone related to growth and development, while improve the metabolic situation of lipid and protein in organism. The antibiotic could be replaced by antibacterial peptide in practical application effectively, and the ideal additive level was300mg/kg in this study. |
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