| In order to alleviate the contradiction between human and livestock competing for food and ensure the growth performance and health of fattening pigs under the background of banning anti substitution antibody,this study aimed to explore the appropriate multi-bacteria solid-state fermentation system,and to investigate the effects of multi-bacteria solid-state fermented diet with different crude fiber(CF)levels on growth performance,nutrient digestion,blood biochemical indicators,fecal microbial flora and short chain fatty acids(SCFAs)of fattening pigs.Test 1:This test aimed to obtain four strains to be fermented through the screening of cellulose degradation ability,and then optimized their mixing ratio and fermentation conditions to obtain the optimal multi-bacteria fermentation system.The experimental results showed that:(1)According to the results of relative enzyme activity and cellulase activity,Lactobacillus amylophilus TZR-PI001(3.9 mm/d,13.25 U/10~4CFU),Candida utilis CICC1314(5.1 mm/d,12.88 U/10~4CFU),Bacillus subtilis ATCC19659(8.2 mm/d,12.70 U/10~4CFU)and Enterococcus faecalis TZR-PI003(3.2 mm/d,11.58U/10~4CFU)were selected.(2)When Lactobacillus amylophilus TZR-PI001:Candida utilis CICC1314:Bacillus subtilis ATCC19659:Enterococcus faecalis TZR-PI003=2:1:1:1,the maximum cellulase activity 12.14 U/10~4CFU was obtained.(3)When the inoculation amount of multi-bacteria was 2.1%,the initial water addition amount was54.0%,and the fermentation time was 3.5 d,the maximum CF degradation rate 30.52%was obtained.(4)Multi-bacteria solid-state fermentation could not only degrade CF,neutral detergent fiber(NDF),acid detergent fiber(ADF),and increase the content of crude protein(CP)in high and low fiber feeds,but also increase the content of soluble sugar,amylase activity,total antioxidant capacity(T-AOC)and inhibit mold growth to improve feed quality.Test 2:This test aimed to study the effects of multi-bacteria solid-state fermented diet with different CF levels on growth performance,nutrient digestion,serum biochemical indexes,fecal microflora and SCFAs of fattening pigs.Using a 2(factors)×2(levels)design,a total of 36 fattening pigs(Duroc×Landrace×Large White)(70.80±5.75 kg)were randomly divided into 4 treatments with 9 pigs in each group.Treatment I:fed a non-fermented basal diet containing 7.00%CF(HF);Treatment II:fed a multi-bacteria solid-state fermented diet containing 7.00%CF(HFM);Treatment III:fed a non-fermented basal diet containing 2.52%CF(LF);Treatment IV:fed a multi-bacteria solid-state fermented diet containing 2.52%CF(LFM),and the experimental period was 28 d.After the end of the test period,information about weight gain,body size and feed intake were collected,and samples of serum,feed and feces were collected.The experimental results showed that:(1)Multi-bacteria solid-state fermented feed significantly increased the backfat thickness of fattening pigs(P<0.05),and high-fiber diet significantly increased the average daily feed intake of pigs and decreased the chest circumference(P<0.05).Both of them had no significant effect on average daily gain(P>0.05).(2)Multi-bacteria solid-state fermented feed significantly increased the total tract apparent digestibility(ATTD)of CP,CF,NDF,ADF,8 amino acids(Trp,Asp,Gly,Cys,Val,Met,Ile and Leu),essential amino acids(EAA),non-essential amino acids(NEAA)and total amino acids(TAA)(P<0.05)and the digest amounts of 5 amino acids(Trp,Glu,Gly,Val,Ile and Leu),EAA,NEAA and TAA(P<0.05).Multi-bacteria solid-state fermented feed significantly decreased the digest amounts of CF,NDF and ADF(P<0.05).High-fiber diet significantly reduced the ATTD of CP,CF,NDF,ADF,Ca,18 amino acids(Trp,Thr,Val,Met,Ile,Leu,Phe,Lys,His,Arg,Asp,Ser,Glu,Gly,Ala,Cys,Tyr and Pro),EAA,NEAA and TAA(P<0.05)and the digest amounts of CP,14 amino acids(Trp,Thr,Ser,Glu,Gly,Ala,Val,Ile,Leu,Phe,Lys,His,Arg and Pro),EAA,NEAA and TAA(P<0.05).High-fiber diet significantly increased the digest amounts of CF,NDF and ADF(P<0.05).(3)Multi-bacteria solid-state fermented feed significantly reduced serum cholesterol(TC),triglyceride(TG),low density lipoprotein(LDL-c),urea nitrogen(BUN)and propylene glycol(MDA)in fattening pigs(P<0.05),increased serum high-density lipoprotein(HDL-c),total protein(TP),albumin(ABL)and glucose(GLU),as well as activities of T-AOC,glutathione Oxidase(GSH-Px),superoxide dismutase(SOD)and catalase(CAT)(P<0.05).High-fiber diet increased serum TC,TG,LDL-c,BUN and MDA(P<0.05),decreased serum HDL-c,TP,ABL and GLU,as well as activities of T-AOC,GSH-Px,SOD and CAT(P<0.05).(4)Multi-bacteria solid-state fermented feed significantly increased the relative abundances of Lactobacillus and Coprococcus(P<0.05),and decreased the relative abundance of Streptococcus in fecal microorganisms(P<0.05).High-fiber diet significantly increased the relative abundances of Akkermansia and Coprococcus(P<0.05),and decreased the relative abundances of Clostridiaceae＿clostridium and Oscillospira in fecal microorganisms(P<0.05).The interaction between them had a significant effect on the relative abundances of Oscillospira and Coprococcus(P<0.05).The biomarkers of HFM group were Coprococcus and Gemmiger,the biomarker of LF group was Oscillospira and the biomarker of LFM group was Bifidobacterium.(5)Both multi-bacteria solid-state fermented feed and high-fiber diet significantly increased the content of acetic acid,propionic acid and butyric acid in the feces of fattening pigs(P<0.05).To sum up,neither multi-bacteria solid-state fermented feed nor the 7.00%CF high fiber diet had a significant effect on the weight gain of fattening pigs(P>0.05).The7.00%dietary CF level had a negative effect on the nutrient digestion and serum biochemical indexes of fattening pigs,but multi-bacteria solid-state fermented feed could alleviate this negative effect and increase the backfat thickness.High-fiber diet and multi-bacteria solid-state fermented feed were able to improve the microbial structure and diversity of fattening pig,and increase the content of SCFAs in feces. |
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