Effect Of Dietary Fatty Acid Saturation On Performance,Meat Quality And DGAT2 Gene In Finishing Pigs

The aim of this study was to investigate the effects of the ratio of unsaturated fatty acids and saturated fatty acids on growth performance,meat quality and DGAT2 gene expression in finishing pigs.The experiment selected 90 healthy Duroc×Landrace×Yorkshire ternary hybrid lean meat type finishing pigs.The test period was 45 days and the experimental group was randomly divided into 6 treatment groups and 5 replicates per treatment group.The first treatment was the control group:added 2%lard to the base diet and treatment of 2?6 groups added 0.4%,0.8%,1.2%,1.6%,2%soybean oil,etc.to the basal diet to replace lard.The U/S of each group was 1.2:1,1.4:1,1.7:1,1.9:1,2.8:1,and 3.0:1,respectively.The results showed that:1.With the increase of U/S ratio in diet,both ADFI and ADG showed a downward trend?P>0.05?.And ADFI and ADG were the lowest when the U/S ratio was 3.0:1.From the F/G results,the difference in feed-to-meat ratio of each treatment group was not significant?P>0.05?.2.The increase in U/S value in the diet significantly reduced the TG content in the serum?P<0.05?,and the lowest when the U/S ratio was 1.9:1.At the same time,the content of HDL was significantly increased?P<0.05?,and the highest when the U/S ratio was 2.8:1.There were no significant differences in serum TC,LDL and VLDL levels between treatment groups?P>0.05?.3.The U/S value in the diet was increased,and the serum SOD content was also significantly increased?P<0.05?.When the U/S ratio was 1.9:1,the SOD content was the highest.The MDA content decreased significantly with the increase of U/S value in the diet?P<0.05?,and the U/S ratio was 2.8:1,the MDA content was the lowest.There was no significant difference in GSH-px and T-AOC content between treatments?P>0.05?.4.The increase in U/S ratio in the diet significantly reduced the backfat thickness of the finishing pigs?P<0.05?,and the U/S ratio was 2.8:1.There was no significant difference in slaughter rate and eye muscle area between treatment groups?P>0.05?.5.Increasing the U/S ratio of diets had no significant effect on the shearing force,drip loss,cooked meat rate,meat color score,p H₁and p H₂of finishing pigs?P>0.05?.6.With the increase of dietary U/S ratio,the levels of LDL and TG in intramuscular fat were significantly decreased?P<0.05?.And the LDL content was the lowest when the U/S ratio was 1.9:1.The content of TG is the lowest when the U/S ratio was 1.7:1;There was no significant difference in LDL,HDL,VLDL and HL content between treatment groups?P>0.05?.In liver fat metabolism,compared with U/S 1.2:1 group,when the U/S ratio was1.7:1,the HDL content in the liver was significantly increased?P<0.05?.Increasing the U/S ratio compared with the 1.2:1 group significantly reduced the TC content?P<0.05?,and the U/S ratio was 1.9:1.7.The increase of U/S ratio in diet had no significant effect on intramuscular fatty acid content of finishing pigs?P>0.05?.However,linolenic acid content in UFA tends to increase,but the difference was not significant?P>0.05?.There was no significant effect on fatty acid content in liver of finishing pigs with the increase of dietary U/S ratio?P>0.05?.8.Increasing the ratio of U/S in the diet significantly reduced the expression of DGAT2gene in the longissimus dorsi muscle?P<0.05?.The U/S ratio was 1.9:1 and the 2.8:1 group had the lowest DGAT2 gene expression compared with the 1.2:1 group.There was no significant difference in the expression of DGAT2 gene in subcutaneous fat of each treatment group?P>0.05?.In summary,the U/S value in the diet was 1.7?3.0,which had a good effect on the performance and meat quality of the finishing pigs.