| Piglet diarrhea,as a multi-factor disease under large-scale farm,has brought great problems to pig farms and serious threat to the sustainable development of animal industry,which has caused low survival rate,decreased growth and feed conversion rate for piglets.Antibiotic abuse will cause the organisms appearance with resistance and tolerance to drugs and deposit in animal products.In this study,the combination of probiotics and berberine with good prevention and treatment effect on piglet diarrheas was studied to make a mixed feed additive for piglet production.This kind of feed additive can replace antibiotics for safe animal production.The main results were as following.(1)Bacterial inhibition experiment by compound probiotics in vitro: Firstly,probiotics with good inhibitory effect on Escherichia coli proliferation were screened in vitro and combined.Escherichia coli and probiotic strains preserved in our laboratory and were incubated in the corresponding liquid medium.Secondly,proliferation inhibition of Escherichia coli in vitro was performed using the Oxford cup.After 24 h incubation,the diameter of antibacterial zone was measured.The results showed that the optimal combination of viable Lactobacillus casei,Enterococcus faecalis,Bacillus subtilis K4 and Saccharomyces boulardii was 1×106,1×107,1×106and 1×107 CFU/m L,the diameter of antibacterial zone was 12.06 mm(P < 0.05).(2)Effect of compound probiotics and berberine on bacterial inhibition in vitro: The selected compound probiotics were combined with berberine for investigating their optimal ratio for inhibiting E.coli proliferation.The compound probiotics were inoculated in liquid MRS medium containing berberine at different concentrations.After culture for 24 h,the inhibitory effect of berberine at different concentrations on the counts of viable probiotics was observed.The result indicated that 0.01% berberine inhibited probiotic proliferation to the minimum.The combination of compound probiotics and berberine made the diameter of antibacterial zone be12.06 mm(P < 0.05).(3)Effects of compound probiotics combined with berberine on growth performance of weaned piglets:200 35-day-old weaned piglets(Duroc×Landrace×Large White)were randomly divided into 5 group,four repeats in each group,10 piglets in each repeat(half male and half female).The experimental period was 42 d.Group A: basic diet without antibiotics and zinc oxide;group B: basal diet + antibiotics(quetiapine ketene,calcium terramycin,methylene salicylic acid)+ zinc oxide(1600 PPM);group C: 0.06% probiotic mixture with berberine;group D: 0.12%probiotic mixture with berberine;group E: 0.18% probiotic mixture with berberine.The results demonstrated that there were no significant differences in daily gain,feed intake,feed conversion rate,and apparent digestibility of crude protein,crude fat,calcium and phosphorus among 5 groups(P > 0.05).The diarrhea rate in the experimental groups was a little lower than the control group(P > 0.05).Amylase activity in the feces of piglets in group E was higher than that in group A and C(P < 0.05);protease activity in the feces of piglets in group D was higher than that in group C(P < 0.05).There were no significant difference in other groups for fecal amylase and protease activity.The results microbial high-throughput sequencing in piglet faeces were as follows: There were a total of 1540 OTUamong 9 piglet,3 piglets in group A,B and C.The OTU number was598 for group A,538 for group B,404 for group C.330 OUT were shared in 3 groups accounting for 21.42% of the total OUT.The unique OTU percentage in group A,B and C was only 3.70%,1.82%,0.71%,respectively.Quality sequence difference between each treatment group was insignificant(P > 0.05).Microflora richness indexes such as Chao and ACE in group A were lower than group B and C(P < 0.05),indicating that the compound probiotics and berberine had some effects on piglet fecal microflora richness.Microbial diversity index of Shannon in group B and C had no significant difference from group A,but a little higher than group A.At phylum level,Bacaeroides were the dominant bacteria in group A,B and C,which was not affected by adding probiotic mixture with berberine or antibiotics.The Bacteroides and Firmicutes in each group accounted for 47.39%~56.7% and 41.23%~48.09% of total sequences,respectively.However,the sequence content of Helicobacter,Cyanobacteria,Fibrobacter and Actinomycetes were all relatively low,which was insignificant different among 3 groups(P >0.05).There was no significant difference among 3 groups for Prevotella,Prevotellaceae_nk31_group,Macrococcid,Unclassified_f__Lachnospiraceae,lactic acid bacteria,Bacteroidales_S24-7_group,Streptococcus,Rikenellaceae_RC9_gut_group and Bacteroides(P>00.05).In this study,the mixed feed additive which can replace antibiotics,reduce diarrhea rate,mortality and culling rate of piglets as well as improve piglet growth performance of piglets has been obtained.It will have the positive effect on pig health and safe animal products. |
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