The Effect Of ɑ-tocopherol And ɑ-tocotrienol On Antioxidant Capacity And Meat Quality Of Growing-finishing Pigs

Vitamin E has 8 isomers.α-Tocopherol has higher bioavailability,butα-Tocotrienol has stronger antioxidant capacity.Under the condition that the total tocopherol remains unchanged,it is worth studying whether a certain amount of tocotrienol can replace tocopherol in the feed to better improve the antioxidant capacity of growing-finishing pigs.The following three experiments were carried out to determine the antioxidant capacity and its impact on pork quality of different proportions ofα-Tocopherol andα-Tocotrienol.Test 1:Comparison of antioxidant capacity ofα-tocopherol andα-tocotrienol at different ratios in vitroThe sum of tocopherol and tocotrienol was kept at 100μmol/L,and 100μmol/Lα-tocopherol was used as control group（TE group）,set 3 different ratiosα-Tocopherol andα-Tocotrienol,respectively 6.5:1（TT1 group）,2.75:1（TT2 group）,1.5:1（TT3 group）.Detect the superoxide anion scavenging rate and the hydroxyl radical scavenging rate.The intestinal epithelial cells（IPEC-J2）were cultured with different proportions ofα-Tocopherol andα-Tocotrienol was co-cultured for 6 h,and then treated with 1 mmol/l Diquat（DQ）for 4 h.Cell viability was measured by CCK-8 method,and intracellular reactive oxygen content was measured by flow cytometry.Results:The Hydroxyl radical scavenging rate in TT3 group was significantly higher than that in control group（P<0.05）;The superoxide anion scavenging rate in TT1 group was significantly higher than that in control group（P<0.05）,TT2 and TT3 groups were significantly higher than the control group（P<0.01）.The pretreatment ofα-tocopherol andα-tocotrienol in different proportions could alleviate the damage of DQ.TT3 had the strongest ability to remove intracellular reactive oxygen species（P<0.01）,TT3 showed the best resistance to oxidative stress of diquat.Test 2:Effects of Different proportions ofα-tocopherol andα-tocotrienol in diets on pork quality,Antioxidant Capacity and muscle fiber Types210 heads,120 days old,60 kg growing-finishing pigs（long×Large,similar body weight,barrow）were randomly divided into five treatment groups.Each treatment group had 6 replicates,and were fed with basic diet（Ctrl group）,while in other groups had the following contents of tocopherol and tocotrienol:75 mg/kg+0 mg/kg（TE group）,65mg/kg+10 mg/kg（TT1 group）,55 mg/kg+20 mg/kg（TT2 group）,45 mg/kg+30 mg/kg（TT3 group）.The formal test will be conducted for 45 days.The feed intake of pigs was recorded during the test and weighed after the test;At the end of the experiment,one（30 in total）of each repeat was randomly selected for slaughtering and sampling.Serum was collected to measure the antioxidant capacity and meat quality of longissimus dorsi muscle.The m RNA expression of myosin heavy chain My HC subunit gene in muscle tissue was analyzed by fluorescence quantitative PCR.Results:Dietary supplementation of 45 mg/kgα-tocopherol+30 mg/kgα-tocopherol（TT3 group）could significantly increase daily gain（P<0.05）,significantly decrease the feed to meat ratio（P<0.05）,and the content of SOD and CAT increased significantly（P<0.05）,while the content of MDA decreased significantly（P<0.05）.When adding 75 mg/kgα-tocopherol（TE group）,the content of collagen was significantly increased（P<0.05）,My HCⅠin muscle fiber types of growing-finishing pigs increased significantly,while My HCⅡb decreased significantly（P<0.05）.Test 3:The relevant samples of TE group,which showed significant changes in antioxidant capacity and muscle fiber type in test 2 were selected.The expression of mitochondrial related genes and Adipo Q signal pathway related genes were analyzed by fluorescence quantitative PCR（q PCR）,short-chain fatty acids in cecum contents were determined by gas chromatography,and the intestinal microorganisms were analyzed by 16S r DNA sequencing.In order to analyze the change mechanism of muscle fiber type.Results:1.Compared with Ctrl group,the m RNA expression of CPTⅠ,PGC-1αin the longissimus dorsi muscle of growing-finishing pigs in TE group increased significantly（P<0.05）,the content of acetic acid in cecum contents of TE group was significantly decreased（P<0.01）,the content of propionic acid and butyric acid was significantly decreased（P<0.05）.2.16S r DNA sequencing analysis showed that at the phylum level,the relative abundance of Cyanobacteria and Teneris in TE group was significantly higher than that in control group（P<0.05）;At the species level,the relative abundance of Eubacterium biform in TE group was significantly higher than that in control group（P<0.05）,and the relative abundance of Ruminococcus flavefaciens was significantly lower than that in control group（P<0.01）.The correlation analysis showed that Ruminococcus was positively correlated with the content of butyric acid and propionic acid（P<0.05）;Bacteroides was positively correlated with DAO（P<0.05）;Peptococcus and collagen content were negatively correlated,and positively correlated with p H_45min（P<0.05）;Prevotella was negatively correlated with collagen content（P<0.05）;Firmicutes was negatively correlated with DAO content（P<0.01）;Eubacterium had a negative correlation with the content of My HC IIa（P<0.05）.The main conclusion of this study is that:1.In vitro experiments showed that TT3 group（α-tocopherol:α-tocotrienol=1.5:1）,its hydroxyl radical scavenging rate and superoxide anion scavenging rate were the highest;It had the best preprotection effect on IPEC-J2 cells and the best antioxidant capacity.2.Dietary supplementation of 45 mg/kgα-tocopherol+30 mg/kgα-tocotrienol（TT3group）can significantly increase the daily weight gain,reduce the feed to meat ratio,and improve the antioxidant capacity of growing-finishing pigs.75 mg/kgα-tocopherol（TE group）did not significantly improve the daily gain of pigs,but could significantly improve the antioxidant capacity,change the type of muscle fiber,and increase the content of collagen in muscle.The dominant flora was significantly correlated with collagen and muscle fiber type.