Study On The Multi-strain Solid Fermenting Process Of Rapeseed Meal And Its Feeding Value For Broilers

The aim of this study was to establish a fermentation process to rapeseed meal detoxificate and improve its feeding value.Based on the screened natural strains that could degrades the glucosinolate in rapeseed meal efficiently and combining with other strains,the solid fermentation technology of multiple strains of rapeseed meal was established.The apparent metabolic energy and the ileal amino acid digestibility of rapeseed meal on broilers before and after fermentation were evaluated.The effect of fermented rape seed meal for broilers was testified and the proper dosage in broiler diet was determinded.The full study was divided into five experiments.In experiment one,this study was to screen natural bacterial strains that can efficiently degrade the glucosinolates in rapeseed meal.A total of 54 strains with good growth were screened and isolated from mixed liquid with fermented silage and soil through cultivating in medium containing glucosinolate?GS?as a sole carbon source.According to re-screening in the solid-state fermentation,strain named A9showed high degradation rate?23.69%?of GS.Strain A9 has been identified as Lactobacillus farciminis after morphological observation and 16s rDNA sequence analysis.Rapeseed meal was fermented through mixing Lactobacillus farciminis with Bacillus subtilis and Saccharomyces cerevisiate.The contents of GS decreased from 37.48?mol/g to 25.96?mol/g while the degradation rate was 30.73%.Polypeptide content increased from 0.84%to 2.62%respectively.The fermented rapeseed meal was yellow-brown and fluffy with a rich sour aroma in which total acid content increased from 1.01%to3.91%.The nutritional value and relish of rapeseed meal was improved efficiently.In experiment two,this study was to optimize the process of mixed bacteria solid state fermentation rapeseed meal.Three strains of Lactobacillus acidophilus,Bacillus subtilis and Saccharomyces cerevisiae were used,and the rate of glucosinolate degradation?X%?,total acid increase rate?Y%?,polypeptide increase rate?Z%?were used as evaluation indices.Method M as the comprehensive evaluation index?M=0.7*X+0.15*Y+0.15*Z?.Taking the addition ratios of the three strains as the experimental factors,the L₉?3⁴?three-factor and three-level orthogonal design experiment was designed to explore the best mixed ratio of the mixed strains fermented rapeseed meal.Taking the fermentation temperature,feed water ratio,time,and inoculum volume as experimental factors,L₁₆?4⁵?four-factor and four-level of orthogonal design experiments was designed to explore the best process of mixed strains solid state fermentation of rapeseed meal.The result shows that the best mixed ratio of the mixed strains of fermented rapeseed mealwas Lactobacillus acidophilus:Bacillus subtilis:Saccharomyces cerevisiae=1:3:2.The best process of mixed strains solid state fermentation of rapeseed meal was fermentation temperature:33?,feed water ratio:1:1,time:84h and inoculum volume:6%.In experiment three,this study was to explore the effect of microbial fermented rapeseed meal on the Apparent Metabolizable Energy of broiler.72AA broilers were assigned into 3 experimental diets with 4 broilers per replicate and 6 replicates.The results showed that the apparent digestibility of rapeseed meal increased significantly after fermentation?P<0.05?.The Apparent digestive energy of rapeseed meal was increased from 7.41MJ/kg to 8.51MJ/kg after fermentation.In experiment four,this study was to explore the effect of fermented rapeseed meal on the Apparent Ileal Digestibility and the Standard Ileal Digestibility of broilers.72AA broilers were assigned into 3experimental diets with 4 broilers per replicate and 6 replicates.The results showed that the digestibility of various amino acids of rapeseed meal was increased to varying degrees after fermentation.The apparent ileal digestibility and standard ileal digestibility of Arg,Lys,Tyr,Leu,and Ile were significantly higher than those unfermented treatment group?P<0.05?.No significant difference in digestibility of other amino acids?P>0.05?.In experiment five,this experiment was designed to study the effect of fermented rapeseed meal on the growth and development of broilers.420 AA broilers were assigned into 7 experimental diets with 10broilers per replicate and 6 replicates.With corn-soybean meal diet as the control,fermented rapeseed meal and unfermented rapeseed meal were set with three addition gradients of 5%,10%and 15%.The results showed that fermented rapeseed meal can improve the production performance of broilers in different degrees,can improve the slaughter rate,the clean-out rate and the reduce the rate of abdominal fat of broilers significantly?P<0.05?.The effect is better than unfermented rapeseed meal.Microbial fermentation of rapeseed meal can significantly increase the spleen index of broilers?P<0.05?and increase the V/C of duodenum and jejunum in broilers?P>0.05?.Microbial fermented rapeseed meal can replace soybean meal in broiler diets,and 15%of fermented rapeseed meal had no significant effect on the control group with no added rapeseed meal?P>0.05?.10%of fermented rapeseed meal has a better production performance,immune indicators and intestinal development status than the control group with added rapeseed meal?P>0.05?.So it is recommended that the amount of fermented rapeseed meal added to broilers can be 10%.