| The objective of the research was to investigate the effect of ferulic acid (FA) and vitamin E (VE) supplementation on the meat quality, anioxidative capacity and NF-E2-related Factor2(Nrf2-ARE) signaling pathway in finishing pigs.To find out that whether the FA and VE can improve meat quality by improving the antioxidant capacity. In addition, by studying the expression of target genes and proteins which relevant to Nrf2-ARE signaling pathway, we can reveal the mechanism of FA and VE in the process of improving antioxidant capacity and analysis the interaction effects between FA and VE. And it will provide the technological and theoretical basis for the application of FA and VE on the pig industry. The research can be divided into three parts:The first part was aim to study the effects of FA and VE on the pork quality of finishing pigs.60healthy barrows were randomly allocated to4treatment groups and were fed four different types of diet for28d before slaughter. Experimental treatments were as follows:basal diets (Control group); the basal diets with100mg/kg FA (FA group); the basal diets with400mg/kg VE (VE group); the basal diets with100mg/kg FA and400mg/kg VE (FA+VE group). After the trial period, from each group6pigs were randomly selected and slaughtered. The results showed that:compared with the control group, the shear force values of the FA group and the VE group decreased significantly (P<0.05), and the eye muscle area increased significantly in the VE group (P<0.05), the cooking loss and inosinic acid (IMP) content decreased significantly in the FA+VE group (P<0.05), but the eye muscle area was markedly increased in the FA+VE group (P<0.01). There were no significant effects of dietary FA and VE on the texture and nutritional components of longissimus dorsi muscle (P>0.05). While compared to the control group and the FA group, VE group and FA+VE group had an increase in a-tocopherol concentration of plasma, liver and muscle tissues (P<0.01).The results of storage life between different groups had shown that:compared with the control group, the FA group decreased the juices loss and MDA level on4d of storage (P<0.01), and had a rising trend in a*value on1d of storage (P=0.079).The VE group increased a*value on45min postmortem (P<0.01)and4d of storage (P=0.069), meanwhile, the VE group decreased the juices loss on2,4d of storage (P<0.01, P<0.05) respectively, and also decreased the malondialdehyde (MDA) content on4d of storage significantly (P<0.05). The FA+VE group significantly increased the pH45min (P<0.01) and decreased the MDA content on4d of storage (P<0.05).In the second part, the experiment was designed to study the effects of FA and VE on the antioxidative capacity in serum, liver and longissimus dorsi muscle of finishing pigs. The results showed that:compared with the control group, the VE group increased the serum catalase enzyme (CAT), glutathione peroxidase enzyme (GPx) activities (P<0.01, P=0.074) and decreased the level of serum MDA (P=0.090), while the serum CAT, GPx activities in FA+VE group were significantly higher (P<0.05). Compared with the control group, the FA group decreased the level of liver MDA significantly (P<0.05) and its CAT activity had an elevated trend (P=0.086). The VE group significantly elevated the total superoxide dismutase enzyme(T-SOD), CAT activities and total antioxidant capacity (T-AOC), glutathione (GSH) level in liver (P<0.01), and declined the level of liver MDA significantly (P<0.01). The FA+VE group increased the liver GPx activity significantly (P<0.01) and existed a rising trend in liver T-SOD activity and GSH level (P=0.055, P=0.057), but decreased the level of serum MDA significantly (P<0.05). Compared with the control group, the FA group and the VE group increased the GPx activity in longissimus dorsi muscle (P=0.057, P<0.05). Moreover, the muscle T-AOC level of the VE group showed an increased trend (P=0.057). The FA+VE group increased the muscle GPx activity significantly (P<0.05) and had a tendency for the GSH level to be elevated (P=0.079). What’s more, the muscle MDA level in the FA group, the VE group and the FA+VE group was significantly decreased (P<0.01).The third part was conducted to study the effects of FA and VE on the Nrf2-ARE signaling pathway in liver and longissimus dorsi muscle of finishing pigs. The results showed that:compared with the control group, the FA+VE group enhance the liver glutathione peroxidase1(GPX), glutamate cysteine ligase catalytic subunit (GCLC) and muscle NAD(P)H quinine oxidoreductase1(NQO1) mRNA expression (P<0.05), and had a tendency to increase the heme oxygenase-1(HO-1) mRNA expression in muscle (P =0.062). Besides, compared with the control group; the FA group, the VE group and the FA+VE group both significantly up-regulated the protein expression of GPX1, GCLC, Nrf2in muscle and liver tissues, and of which we also observed an increasing nucleus Nrf2protein level in liver and muscle cells as well, showing that dietary supplementation of FA and VE could activate Nrf2-ARE pathway and enhance Nrf2nuclear translocation.As stated above, the conclusions are as follows:(1) Diets supplemented with FA or VE could significantly reduce the shear force value and improve the tenderness. Supplementation with VE alone or in combination with FA, could elevate the eye muscle area and increase the a-tocopherol concentration in plasma, liver and muscle tissues. Otherwise, Supplementation with400mg/kg VE or100mg/kg FA, could effectively improve the colour stability, inhibit lipid oxidation and reduce juices loss during storage time, which were effective to extend the storage time of pork, but when supplemented with VE and FA together, there was no synergetic effect to be observed.(2) Diets supplemented with FA or VE could effectively increase activities of antioxidant enzymes in serum, liver and muscle, increase the level of GSH in liver and muscle, and reduce the MDA content in liver and muscle. All of these indicated that supplementation with FA and VE was effective to improve antioxidative capacity of finishing pigs.(3) Diets supplemented with FA and VE could effectively activate the Nrf2-ARE signaling pathway in liver and muscle, and then promote Nrf2nuclear translocation, up-regulate the mRNA and protein expression of downstream target genes, in which the FA+VE group had the most obvious effect. |
PDF Full Text Request