摘要
Abstract
To investigate the improvement effect of mixed-strain fermentation on the nutritional value of dis-tillers' grains feed and its regulatory mechanism on rumen function in beef cattle,Chinese Baijiu distillers'grains were used as raw material and subjected to solid-state fermentation with a mixed strain system of Aspergillus niger,Bacillus subtilis and Saccharomyces cerevisiae at a ratio of 1:1:2,and then a 90-day feeding trial was conducted.Thirty 2-year-old Simmental crossbred beef cattle with an initial body weight of(380±21.5)kg were randomly divided into 5 groups:the control group(CON)was fed a basal diet with 20％unfermented distillers' grains as an equal replacement,while the treatment groups F1,F2,F3,and F4 were fed diets with 20％,40％,60％,and 80％fermented distillers' grains as equal replacements,respec-tively.The results showed that compared with pre-fermentation,the contents of crude protein,true protein,calcium and total phosphorus in fer-mented distillers' grains were significantly increased(P<0.05),while the contents of neutral detergent fiber and acid detergent fiber were sig-nificantly decreased(P<0.05),and the contents of total amino acids,lysine,methionine,threonine,valine,leucine,glycine,alanine,serine,glutamic acid,aspartic acid,phenylalanine and histidine were also signifi-cantly increased(P<0.05);compared with the CON group,ruminal pH in the F4 group was significantly decreased(P<0.05),the ammonia nitrogen content in the F3 group was significantly lower than that in the CON,F1 and F4 groups(P<0.05),and the total volatile fatty acid content was significantly higher than that in all other groups(P<0.05),meanwhile the F3 group had the lowest acetate proportion and acetate/propio-nate ratio as well as the highest microbial protein content;the apparent digestibility of dry matter,neutral detergent fiber and acid detergent fiber in the F3 group was the highest and significantly higher than that in all other groups(P<0.05);the final body weight and average daily gain of the F3 group were the highest and significantly higher than those of all other groups(P<0.05),the feed conversion ratio of the F3 group was sig-nificantly lower than that of the CON,F1 and F4 groups(P<0.05),and the cost per kg weight gain in the F3 and F4 groups was significantly lower than that in all other groups(P<0.05).In conclusion,mixed-strain fer-mentation can effectively improve the nutritional value of distillers' grains,and the 60％substitution level presents the optimal effect.关键词
混合菌发酵/酒糟饲料/肉牛/瘤胃发酵/养分消化率/生长性能Key words
mixed-strain fermentation/distiller's grains feed/beef cattle/rumen fermentation/nutrient digestibility/growth performance分类
农业科技
