A Preliminary Study On The Effect Of Dietary Supplementation Of Edible Oil On Growth And Meat Quality Traits In Fattening Cattle

As a kind of high-protein meat,beef consumption in meat products has been among the top three in the world.Fattening effect and beef quality directly affect the economic benefits of raising.High-quality livestock products are not only favored by the market,but also can increase feeding remuneration.At present,China is in the context of the transformation and upgrading food consumption structure.The demand for beef continues to rise,while the domestic beef cattle industry is still in the development stage,unable to provide a large number of high-quality beef products to the market.The quality of beef is affected by many factors,such as pH,meat color,marbling,tenderness and juiciness.In the high quality beef cattle fattening production,the content of intramuscular fat is insufficient,and large deposition of subcutaneous fat has become an urgent problem to in the industry.Oleic acid is a long-chain unsaturated fatty acid of 18-carbon-9-enoic acid,which has the effect of promoting adipocyte differentiation and fat deposition in a variety of species.In addition,unsaturated fatty acids are more beneficial to the human body than saturated fatty acids,and oleic acid has a positive effect on immune regulation and prevention of different types of diseases.Oleic acid is ubiquitous in edible oils,with an oleic acid content of about 22.8% in soybean oil and about 57.3% oleic acid in rapeseed oil.Therefore,this research aims to increase the proportion of oleic acid in the feed of fattening cattle by adding 3% soybean oil or rapeseed oil to the diet,promote the deposition of intramuscular fat(IMF)in fattening cattle,improve the growth traits and meat quality traits of beef cattle,and increase the content of unsaturated fatty acids in beef to achieve the purpose of producing high-quality beef.In this study,nine healthy,similar age and body weight cross-fattening Chinese Simmental cattle were selected.They were divided into 3 groups with 3 heads in each.The diet treatment groups were: control group(NC,basal diet),soybean oil group(SO,basal diet+ 3% soybean oil),rapeseed oil group(CO,basal diet + 3% rapeseed oil),and the prefeed period was 15 days followed by 90 days of feeding.During the trial period,the feed intake,blood indexes and growth indicators of the cattle were measured.After the feeding period,the cattle were slaughtered and sampled.The slaughter and meat quality performance,the fat content and fatty acid ratio of the longissimus dorsi muscle were determined,and transcriptome sequencing was performed.The main findings of the study are as follows:1.The addition of edible oil to the diet has no significant effect on the growth performance of fattening cattleThere was no significant difference in average daily gain between the treatment group and the control group during the trial period(P>0.05).There were no significant differences in weekly feed intake,dry matter intake,blood biochemical indexes and carcass weight after slaughter in fattening beef cattle during the trial period(P>0.05).2.The addition of cooking oil to the diet significantly improves the tenderness of beefThe shear force of the longissimus dorsi muscle in fattening cattle decreased significantly with the increase of oleic acid concentration of edible oil added to the diet,among which the shear force of the longissimus dorsi muscle in the SO group was significantly lower than that in the NC group(P<0.05),the shear force of the longissimus dorsi muscle in the CO group was significantly lower than that in the NC group(P<0.01),the flesh-colored brightness(L~*)in the SO group and CO group was significantly lower than that in the NC group(P<0.05),and the flesh yellowness(b~*)in the CO group was significantly lower than that in the NC group(P<0.05).There was no significant difference in cooking loss,water binding capacity and pH of the longissimus dorsal muscles(P>0.05).3.The addition of edible oil to the diet increases the IMF content and the proportion of unsaturated fatty acidsThe IMF content of the longissimus dorsi muscle in fattening cattle increased significantly with the increase of the concentration of oleic acid in diet.Among them,the CO group was significantly higher than that in the NC group and the SO group(P<0.05),and the fat content in the CO group in subcutaneous fat was significantly higher than that in the NC group(P<0.05).The unsaturated rate of fatty acids in the CO group was higher than that in the NC group and the SO group(P>0.05),indicating that the addition of rapeseed oil to the diet increased the proportion of unsaturated fatty acids in beef.4.The addition of edible oil to diets affects gene expression in lipid metabolism pathwaysFurthermore,Transcriptome sequencing of the longissimus dorsi muscle showed that the differential genes in the longissimus dorsi muscle in the CO vs NC group were enriched in the PPAR signaling pathway(P<0.05),and the significantly different gene in the pathway was glycerol kinase2(Glyceras E2,GK2)and carnitine O-palmitoyltransferase 1A(CPT1A)(P<0.05).This study showed that the addition of different edible oils to the diet had no significant effect on the growth performance of fattening cattle,but could increase the tenderness,IMF content and unsaturated fatty acid ratio of beef.This study provides a theoretical basis for the production of high-grade beef.