| Pork is one of the most consumed meat types in many countries around the world.With the improvement of the quality of life,people have higher and higher requirements for the quality of pork.They are no longer satisfied with satiety,but pursue higher nutritional value and taste.Oxidation is not only the main non microbial cause of meat quality deterioration,but also one of the biggest economic problems in the meat industry.It not only loses nutritional quality,limits shelf life,but also increases toxicity and reduces market value.Fat metabolism can also affect meat quality by changing the composition of fatty acids in the body.Rosmarinic acid(RA),which is famous for its strong antioxidant activity,is a naturally occurring phenolic acid found in herbs such as Perilla family.The addition of herbaceous plants containing RA bioactive components to livestock diets has shown good effects in promoting growth,improving reproductive performance and feed utilization,and enhancing antioxidant and immune capacity.In addition,RA is favored in the meat processing industry because it can extend the shelf life and improve product quality.In this study,"Duroc ×Landrace × Yorkshire" three-way crossbred pigs were used as experimental animals to explore the effects of RA on antioxidant and fat metabolism of fattening pigs,so as to provide some theoretical support for the application of RA in improving the quality of fattening pigs.The results of this study are as follows:1.RA can improve the growth performance,meat quality and immunity of finishing pigs.A total of 60 finishing pigs from the same batch and the same health status were randomly divided into three groups: control group(common diet),100mg/kg RA group(common diet + 100mg/kg RA),200mg/kg RA group(common diet + 200mg/kg RA).Blood and longissimus dorsi muscle samples were collected for detection and analysis.Results show:(1)Growth performance: supplementation of RA in diets did not significantly increase the average daily gain(ADG),average daily feed intake(ADFI)and feed/gain ratio(F/G)(p>0.05),but there is a tendency to improve ADG.(2)Slaughter performance: RA treatment significantly increased the slaughter rate and lean meat rate compared with the control group(p<0.05),and the backfat thickness and fat rate were significantly lower than those in the control group(p<0.05).(3)Meat quality: RA can significantly improve the meat color score,marbling score and the content of intramuscular fat(IMF)(p<0.05),and significantly reduce shear force and drip loss(p<0.05).(4)Serum biochemical parameters: the total protein(TP)and Ig M levels of RA treated group were significantly higher(p<0.05).And the activities of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)were significantly decreased(p<0.05).The results indicate that RA can effectively improve the growth performance,slaughter performance and meat quality of fattening pigs,and enhance their immunity.2.RA can enhance the antioxidant capacity of finishing pigs.The serum,liver and muscle of fattening pigs were collected,and the activity of antioxidant enzymes was detected by kit.Results show:(1)In serum,the activities of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GSH-Px)were significantly increased in RA treatment group(p<0.05),and the content of malondialdehyde(MDA)decreased significantly(MDA)(p<0.05).(2)In the liver,RA significantly decreased the MDA content(p<0.05).RA can significantly improve the activities of SOD,CAT and GSH-Px(p<0.05).And RA can enhance the expression level of SOD2 protein and m RNA(p<0.01).(3)In muscle,RA significantly decreased the MDA content(p<0.05).RA can significantly improve the activities of SOD,CAT and GSH-Px(p<0.05).And RA can enhance the expression level of SOD2 protein and m RNA(p<0.05).These results indicate that RA can significantly enhance the antioxidant capacity of the body.3.RA can improve fat metabolism in finishing pigs.In this study,the blood lipid level in serum was detected.And investigated the effects of RA on the expression levels of genes and proteins related to lipolysis and lipid synthesis by q PCR,Western blot,and histological section staining in subcutaneous adipose and liver tissues.Results show:(1)RA could significantly reduce the contents of total cholesterol(TC),low density lipoprotein(LDL)and triglyceride(TG)in serum(p<0.05)and increase the content of high-density lipoprotein(HDL)in serum(p<0.05).(2)In subcutaneous adipose tissue,HE staining showed that RA significantly reduced the size of adipocytes(p<0.05).At the level of protein and m RNA expression,RA significantly down regulated the expression of fat synthesis related genes compared with the control group(p<0.05),and the expression of lipolysis increased significantly(p<0.05).(3)In liver tissue,oil red O staining showed that RA could reduce lipid deposition(p<0.05).At the level of protein and m RNA expression,the expression of fat synthesis and decomposition in the RA treatment group were significantly different from those in the control group(p<0.05).The results showed that RA could increase the expression level of lipolysis related protein and m RNA,and inhibit the expression level of lipid synthesis related protein and m RNA,thereby effectively improving lipid metabolism.To sum up,adding RA to the diet effectively improved the growth performance,slaughter performance and meat quality of finishing pigs,enhanced the immune level and antioxidant level of the body,promoted the process of fat decomposition and inhibited the process of fat synthesis,so as to reduce fat deposition.This study provides experimental support for RA as a feed additive to improve livestock and poultry production performance and meat quality. |
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