Effects Of Grape Pomace Replacing Wheat Bran On Growth Performance And Meat Quality Of Finishing Pigs

In recent years,with the rapid development of China’s economy and the continuous improvement of national living standards,people’s demand for high-quality pork is getting higher and higher.Due to the impact of the trade war between China and the United States,the prices of feed materials such as soybean meal and corn continue to rise.At the same time,affected by the pig cycle,pig prices continue to fall;The income of pig breeding is decreasing and even appears serious deficit.Therefore,how to develop and utilize nongrain feed such as agricultural and sideline products,save money and increase efficiency and improve meat quality has become an urgent problem to be solved in pig production.As the main grape production area in China,northwest China is rich in grape pomace resources.However,it is underutilized.Studies have shown that grape residue is rich in a variety of bioactive substances such as anthocyanins,resveratrol and flavonoids.At the same time,the price of grape pomace is low compared with wheat bran and other feed ingredients.Therefore,it is a potential feed resource.In this study,grape pomace was used to replace all wheat bran in the diet of finishing pigs.RT-q PCR,RNA-Seq and metabolomics techniques were used to investigate the effects of grape residue on growth performance and meat quality of finishing pigs.Twenty-four growing and finishing pigs(55.14±0.59kg)were randomly divided into two groups with 12 pigs in each group.Pigs in control group were fed with ordinary diet,and pigs in experimental group were fed with grape pomace diet.Slaughter analysis was conducted when the body weight reached 115 kg.The main results are as follows:1.Compared with the control group,there were no significant differences in average initial body weight(AIW),average finishing body weight(AFW),average daily gain(ADG),average daily feed intake(ADFI)and feed to meat ratio(F:G)between the experimental group and the control group(P > 0.05).There were no significant differences in carcass weight(HCW),slaughter rate(SR),eye muscle area(EMA)and other carcass traits(P > 0.05).However,compared with the control group,the experimental group saved22.66 yuan per pig during the whole experiment period.2.Compared with the control group,there were no significant differences in p H,meat color and shear force of finishing pigs in experimental groups(P > 0.05),but water loss(WL),drip loss(DL)and cooking loss(CL)were significantly decreased in experimental groups(P < 0.05).T-aoc and SOD activities of longissimus dorsi muscle of finishing pigs were significantly increased(P < 0.05),while MDA content and ROS activity were significantly decreased(P < 0.05).3.Metabolic group analysis showed that compared with control group,the contents of alanine,cardamomoleic acid(C14:1)and stearic acid(C18:0)in longissimus dorsi muscle of finishing pigs in experimental group were significantly increased(P < 0.05);The contents of polyunsaturated fatty acids such as linoleic acid(C18:2N6)and eicosapentaenoic acid(C20:4N6)were significantly increased(P < 0.05);There was no significant difference in restricted amino acid content(P > 0.05).4.Transcriptome analysis showed that a total of 50 differential genes were identified,of which 27 genes were significantly up-regulated and 23 genes were down regulated.Through go and KEGG enrichment analysis,the differential genes were mainly enriched in MAPK signaling pathway,insulin signaling pathway,metabolic pathway and other pathways related to glucose and lipid metabolism.RT-q PCR analysis showed that the expression of kcnh2 gene in the longissimus dorsi muscle of the experimental group was significantly down regulated,and the expression of tecrl,KDSR,LPL,MGST1,FZD1 were significantly up-regulated(P<0.05),which was consistent with the results of the transcriptome.In conclusion,the substitution of grape pomace for wheat bran has no significant effect on the growth performance and carcass traits of finishing pigs,but it can improve meat quality,significantly improve the antioxidant performance of muscle and reduce feed cost.This study provides data and theoretical basis for the development of new non grain feed resources to improve pork quality and save cost and increase efficiency.