| The increasing domestic demand for beef has led to higher consumer demand for meat quality.It is well known that breeds affect the yield and meat quality of beef,and genetic improvement and crossbreeding is one of the effective ways to improve meat quality.Therefore,there is great potential for comparative studies on meat quality of different breed crosses.This experiment aims to compare the differences of beef quality and blood indexes between Simmental cattle and their crossbred fattening cattle,explore the relationship between intestinal flora of beef cattle on the improvement of intestinal short-chain fatty acids and meat quality,and use the transcriptome to reveal the mechanism of cross utilization on body metabolism and meat quality,so as to reveal the correlation between beef quality and glycolipid metabolism,with a view to provide some theoretical support for the improvement of beef quality by cross utilization.Our study showed that hybrid utilization could significantly improve glucose metabolism and meat flavor in beef cattle by regulating insulin signaling pathway and altering fatty acid composition.The study was conducted at Inner Mongolia Tianmuzhen Meat Industry Co,Ltd,and three Simmental cattle(S group),Simmental × Holstein cattle(SH group)and Simmental× Mongolian cattle(SM group),each with healthy body condition and similar age and weight,were divided into three groups and fattened and slaughtered under the same feeding management conditions,and samples of blood,rectal contents and longest back muscle of the test cattle were collected for determination and analysis.The results showed that The results showed that:Test 1: The glucose content of the SM group was significantly higher than that of the S group,and the crossbred beef samples a* in both the SM and SH groups were significantly higher than that of the S group,indicating that the crossbred beef samples in the SM and SH groups were redder than that of the Simmental cattle.the myoglobin and iron content of the crossbred cattle in the SM and SH groups were higher than that of the Simmental cattle,and the SM group had higher levels of internal glucose metabolism and nutrient utilization of the organism.Test 2: The acetic acid content of crossbred fattening cows in the SH group was significantly higher than that of crossbred fattening cows in the SM group,the ratio of intestinal thick-walled Firmicutes/Bacteroides was higher in crossbred fattening cows in the SM group than in the S group,the relative abundance of intestinal cyanobacteria was extremely significantly lower in crossbred fattening cows in both groups than in Simmental fattening cows,and the relative abundance of intestinal Bacteroides was significantly higher in both groups of crossbred fattening cows than in the S group.The short chain fatty acid producing Rikenobacteriaceae RC9 intestinal group showed high abundance in the SM group of crossbred beef cattle,indicating that crossbreeding could reduce cyanobacterial toxins in the intestine of beef cattle and facilitate the formation of healthier intestinal immunity.The intestinal flora of crossbred feedlot cattle had a greater ability to break down cellulose,which could produce more energy for the organism and improve its resistance.Crossbreeding also improves the redness of Simmental beef by increasing the relative abundance of the intestinal Actinobacteria and Bifidobacteria.Test 3: In this experiment,the content of C12:0,C15:1 and C18:3n6 in the longest dorsal muscle of SM group was significantly higher than that of S and SH groups.The antimicrobial properties and the ability to maintain the balance of glucolipid metabolism of fattened cattle in SM group were better than those of the other two groups.The content of erucic acid,HOMO-γ-linolenic acid in UFA in the longest back muscle of fattened cattle crossed with Mongolian cattle was significantly higher than that of the SH group,indicating that crossbreeding with Mongolian cattle was better in maintaining higher levels of UFA in the muscles of Simmental cattle,especially the content of erucic acid,HOMO-γ-linolenic acid.The content of UFA and MUFA in the SM group was significantly higher than that of the S and SH groups,proving that the beef from fattened cattle crossed with Mongolian cattle had more flavor-related fatty acids and the meat was richer in flavor.The transcriptome was annotated with a total of 27,607 genes and 43,984 transcripts,of which 12,626 genes were co-annotated.The blood glucose level in the hybrid-modified SM group was significantly higher than that in the S group.Compared with the S group,the SM group had 49 differently expressed genes(DEG),of which 18 genes were up-regulated and 31 genes were downregulated,while the SH group had 1031 DEG,of which 251 genes were up-regulated and780 genes were down-regulated.In the enrichment analysis,the insulin signaling pathway was significantly enriched in both heterozygote groups.In conclusion,the crossbred beef cattle of SH and SM groups had better energy and fat storage capacity and better redness in meat color than the S group.Crossbreeding can improve energy acquisition,nutrient digestion and absorption ability.The S and SM groups had more unsaturated fatty acids,better disease resistance,and more fatty acids that could improve cardiac metabolism.The transcriptome suggests that this may be closely related to the insulin signaling pathway.Therefore,this study demonstrated that the use of crossbreeding can improve the meat quality and its energy and fat metabolism and enhance the intestinal immunity in beef cattle,and the differential expression analysis of relevant differential genes was performed.It is expected to provide some data support and theoretical basis for beef cattle selection and crossbreeding for efficient production. |
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