| In this study,twenty four Chinese Holstein cows with the same health,similar body weight,the same parity,and about 3 weeks postpartum were randomly divided into two groups,each group with 12 repetitions.The groups were HC that was fed high ratio of concentrate-to-roughage(60:40)and LC group that was fed low ratio of concentrate-to-roughage(40:60).By studying the effects of these different ratio of concentrate-to-roughage diet on the rumen fermentation,bacterial structure and serum biochemical indexes of dairy cows.This paper aims to provide a scientific and theoretical basis on making up a reasonable diet ratio in actual aquaculture production.The results of experiment were as follows:Experiment 1:The effect of different ratio of concentrate-to-roughage diet on the rumen fermentation of dairy cows.For the rumen volatile fatty acid content,the content of propionic acid in the HC group was extremely significant higher than that in the LC group(P<0.01),the acetic acid/propionic acid value was extremely significant decreased(P<0.01),butyric acid and acetic acid content was not significant(P>0.05),but the acetic acid content was lower than that in the LC group.The NH3-N concentration and pH were not significant between the two groups(P>0.05).Experiment 2:The effect of different ratio of concentrate-to-roughage diet on the rumen flora of dairy cows.At the level of phylum in bacterial flora,the abundance of Bacteroides,Fibrobacteres,Firmicutes,SRI,Verrucomicrobia,Tenericutes,TM7,Lentisphaerae and Elusimicrobia in the LC group was extremely significant higher than that in the HC group(P<0.01),while the abundance of Proteobacteria and Spirochaetes was extremely significant lower than that in the HC group(P<0.01).At the level of genus in bacterial flora,comparing with the HC group,the abundance of Ruminococcus,Fibrobacter,Butyrivibrio and Succiniclasticum in the LC group was significantly or extremely significant increased(P<0.05 or P<0.01).The abundance of Treponema and Coprococcus in the HC group was extremely significant increased than that in the LC group,but the abundance of Prevotella had no sinificant different(P>0.05).At the level of phylum in the fungi,the abundance of Ascomycota and Basidiomycetes in the HC group was extremely significantly higher than that in the LC group(P<0.01),while Mortierellomycota was extremely significant lower than that in the LC group(P<0.01).Between the two groups,there was no significant difference in the abundance of the Mucoromycota and Neocallimastigomycota(P>0.05).At the level of genus in the fungi,the abundance of five kinds Yeasts,Piromyces,Neocallimastix,Pleospora and Caecomyces in the HC group was extremely significant or significantly increased than that in the LC group(P<0.01 or P<0.05),but the abundance of Orpinomyces,Cyllamyces,Anaeromyces,Aspergillus and Candida was extremely significant or significantly decreased(P<0.01 or P<0.05).Experiment 3:The effect of different ratio of concentrate-to-roughage diet on functional genes of rumen microorganism in dairy cows.In the KEGG metabolic pathway,it was found that the rumen microbial functional genes mainly concentrated on the carbohydrate metabolism pathway in the two groups.Among them,the number of annotated genes in the starch and sucrose metabolism and the glycolysis gluconeogenesis pathways in the HC group were higher than that in the LC group,but the pyruvate metabolism was decreased.From the CAZy functional analysis,in the GH family,the abundance of cellulase and hemicellulolytic enzyme families GH5S GH9,GH8,GH11 and GH16 in the LC group was significantly or extremely significant increased than that in the HC group(P<0.05 or P<0.01),the abundance of GH3 and GH32 in the LC group was lower than that in the HC group.In the CBM family,the abundance of CBM6 and CBM50 in the LC group was significantly higher than that in the HC group(P<0.05),and the abundance of CBM32 was significantly lower than that in the HC group(P<0.05).For the CE family,the abundance of the CE12 and CE8 in the HC group was significantly or extremely significant increased than that in the LC group(P<0.05 or P<0.01),while the abundance of CE7 was extremely significant decreased(P<0.01).Experiment 4:The effect of different ratio of concentrate-to-roughage diet on serum biochemical parameters of dairy cows.Integrating serum biochemical indicators,there was no significant effect the serum biochemical indices of dairy cows(P>0.05).In summary,comparing with low ratio of concentrate-to-roughage diet,Under premise of maintaining milk production,the high ratio of concentrate-to-roughage diet reduces the pH of the rumen,inhibits the growth of some fiber-degrading bacteria,promotes the proliferation of a large number of acid-producing bacteria,and affects the balance of rumen nicro-ecology,but improves the nutritional metabolism of dairy cows to some extent Therefore,the reasonable ratio of concentrate-to-roughage diet plays an important role in developing of animal husbandry. |
PDF Full Text Request