The Roles And Mechanisms Of Phytol On The Meat Quality Of Finishing Pigs

Pork quality is an important economic traits in pigs,including meat color,tenderness,pH value,hydraulic and flavor et al.Meat quality is affected by a variety of factors,such as muscle fibers type,intramuscular fat and muscle protein deposition et al.Phytol is a branch of plant chlorophyll molecules,belonging to a kind of fatty alcohol,and it can be metabolized to produce phytate and phytate acid in the liver of animals,which play a variety of biological effects.Some study reported that phytol can regulate the change of skeletal muscle fibers type.However,it still is not clear that the effects of phytol on regulating growth performance and meat quality,and its mechanisms are still to be revealed.This study includes following the five parts.Experiment 1: Effects of diary supplementation of phytol on growth performance and meat quality.To research whether phytol regulate growth performance and the formation of meat quality of finishing pigs,ternary miscellaneous finishing pigs were used as research model in the experiment.0.01%,0.05% and 0.1% phytol were respectively supplemented into diary of finishing pigs,and we would observe the effects of phytol on growth performance and meat quality of finishing pigs,and measure serum lipid metabolism items and the expression of lipid metabolism and protein metabolism related genes in the muscle of finishing pigs.The results showed that there was not effect on growth performance of finishing pigs by diary supplementation of phytol.But 0.05% and 0.1% phytol could significantly increase eye muscle area and marble score,and improve pH24 h value and intramuscular fat levels in longissimus dorsal muscle.Further,we found that phytol could significantly reduce triglycerides and free fatty acid levels in pigs serum,and inhibit the expression of lipolysis genes ATGL in longissimus dorsal muscle,thereby inhibiting the decomposition of intramuscular fat.At the same time,phytol also significantly reduced the expression of protein degradation related genes,MuRF1 and MAFbx.Furthermore,phytol could activate Akt/mTOR signaling pathway to increase protein deposition.Experiment 2: the mechanisms of phytol promoting skeletal muscle protein synthesisThe above study found that diary supplementation of phytol could significantly increase eye muscle area and skeletal muscle protein synthesis in finishing pigs.Further,to reveal its mechanisms,C2C12 cells were used as this experiment model,and were co-treated with phytol and the inhibitor of Akt and mTOR to research the signaling pathway of phytol on regulating skeletal muscle protein deposition.The results showed that both 50 ?M and 200 ?M phytol could significantly improve the total protein levels of C2C12 cells,and promote phosphorylation of S6 and the expression of MHCII.By blocking mTOR,Rapomycin could significantly inhibit the effects of phytol on promoting preotin synthesis in C2C12 cells,and block the effects of phytol on the phosphorylation of m TOR downstream,S6 and 4E-BP1.But by blocking Akt,Wortmannin could not block the effects of phytol on promoting preotin synthesis in C2C12 cells and on the phosphorylation of mTOR downstream,S6 and 4E-BP1.The above results showed that phytol could promote skeletal muscle protein deposition by activating the phosphorylation of mTOR and its downstream signaling molecular.Experiment 3: The effects and mechanisms of phytol in the differentiation of adipocytes in porcine intramuscular preadipocytesThe above research also found that phytol could significantly increase and marble score intramuscular fat levels in longissimus dorsal muscle.Further,to reveal its mechanisms,porcine intramuscular preadipocytes were used as the objects to investigate the roles of phytol on porcine intramuscular preadipocytes differentiation in vitro.The results showed that 50 ?M and 200 ?M phytol could dose-dependently increase the triglyceride levels and lipid droplet diameters of porcine intramuscular preadipocytes.Moreover,phytol significantly promote the phosphorylation of PI3K?Akt and FoxO1,and increase the expression of lipid synthesis genes PPAR? and CEBP? and inhibit the phosphorylation of lipid degradation genes ACC and HSL,thereby promoted porcine intramuscular preadipocytes differentiation.Experiment 4: The effects and mechanisms of phytol on glucose uptake and the differentiation of adipocytes in 3T3-L1 cellsThe source of fatty acids had two ways in the process of differentiation in adipocytes cells.The first one was the uptake of extracellular fatty acids,and the second was to produce fatty acids by using intracellular metabolites.The metabolism of cellular glucose is closely related to the synthesis of fatty acids.And to investigate whether the effect of phytol on promoting intramuscular preadipocytes differentiation is related to the uptake of glucose,3T3-L1 cells were used as objects to investigate the effects and mechanisms of phytol on glucose uptake and adipocytes differentiation.The results showed that phytol significantly promoted the uptake of glucose and dose-dependently increased the triglyceride levels and lipid droplet diameters in 3T3-L1 cells.Phytol significantly promoted the expression of GLUT4?PPAR??aP2 and C/EBP?.Furthermore,phytol significantly activated PI3K/Akt signaling pathway.Experiment 5: the roles and mechanisms of phytol on mice glycolipid metabolismThe glucose metabolism is closely related to lipid metabolism in animals.The above study found that phytol significantly promoted the adipocytes glucose uptake and cells differentiation in vitro.The experiment used high glucose and high fat induced C57 BL / 6J obese mice as objects to investigate whether phytol could regulate the glucose and lipid metabolism of animals at the living level.We observed that the effects of phytol on mice glycolipid metabolism by oral administration of phytol different content.The results suggested that oral administration of phytol could significantly reduce blood glucose and serum insulin levels in mice and reduce mice subcutaneous fat and epididymal fat weight.At the same time,phytol significantly increased serum free fatty acids levels and glucose tolerance of mice.Phytol significantly activated PI3K/Akt signaling pathway and the expression of GLUT4.The above results suggested that phytol could significantly promote mice glycolipid metabolism by insulin signaling pathway.In summary,the results of this study showed that diary supplementation of 0.05% and 0.1% phytol could significantly increase the longest musculocutaneous eye muscle area and marble score of finishing pigs and improve skeletal muscle protein deposition and intramuscular fat levels.Its mechanisms included two hand effects.One hand,phytol promoted adipocytes differentiation of intramuscular fat by PI3K/Akt signaling pathway,on the other hand,phytol promoted skeletal muscle protein deposition by mTOR signaling pathway,thereby to achieve the regulation of pork quality.Phytol could also promote mice glycolipid metabolism by insulin signaling pathway.The above results not only have important reference value for the effective regulation of pork quality in pig production,but further research on the regulation of glycolipid metabolism and the promotion of animal and human health.