Effects Of Lycopene Extract On The Meat Quality Of Bamei Lamb And Its Antioxidant Mechanism

Six experiments were conducted to investigate the effects of tomato lycopene supplement on the meat quality of Bamei lamb and its antioxidant mechanism.28male weaned Bamei lambs (90days old) with an average live weight of19.34±2.21kg (mean±SD) were equally assigned, on the basis of body weight, to the basal diet (Control) and basal diet supplemented with50,100and200mg lycopene/kg feed intake. The feeding trial was lasted for120days. Experiment1:Effect of lycopene on growth performance, rumen fermentation parameters and hormone in Bamei sheep. The present study showed that dry matter intake increase with increasing lycopene addition (P<0.05), and average daily weight gain increased, compared to the control (P=0.086, quadratically). As to the rumen fermentation parameters, lycopene had a increased effect on the pH value and NH3-N concentration in rumen (P<0.05), while has a decreased effect on the content of acetic acid, propionic acid and butyric acid content (P<0.05), which resulted in the decrease in the content of total volatile fatty acid (P<0.05). The100mg/kg treatment group rumen fermentation parameters were in an optimal state among the four groups. Compared with the control group, lycopene supplement groups increased the content of plasma IGF-1, T3and T4. Experiment2:Effect of dietary lycopene supplementation on carcass performance, meat quality, fatty acid profile in feedlot Baimei lambs. The results showed that hot carcass weight, GR values, carcass muscle, muscle/bone ratio, and loin eye area tended to increase in a quadratic manner with the increase of lycopene (P<0.10). Meat quality results showed that the pH value at24h has a increased trend in lycopene-added groups.Ddietary lycopene make the meat had lower lightness and hue angle values at24h (P<0.05). Muscle fat content declined in the lycopene-supplemented groups (P<0.05), while polyunsaturated fatty acids increased compared with the control group (P<0.05). Experiment3:Effect of dietary lycopene supplementation on blood enzyme activities, lipid metabolism and low-density lipoprotein receptor protein (LDL-R) mRNA expression. The results showed that dietary supplementation of lycopene reduced creatine kinase, lactate dehydrogenase, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and improved the content of HSP70. Dietary lycopene supplementation significantly reduced the levels of plasma total cholesterol (TC, P<0.05, linearly), total triglycerides (TG, P<0.05) and low-density lipoprotein cholesterol (LDL-C, P<0.05), and atherogenic index (AI, P<0.001) as well. Malondialdehyde (MDA) level in plasma, liver and muscle decreased linearly with the increase of lycopene inclusion levels (P<0.05). In addition, lycopene intake increased the mRNA expression of LDL-R in liver (P=0.077) and muscle (P <0.05). Experiment4:Effect of dietary lycopene supplementation on antioxidative performance during the periods of aging of muscle in sheep. The results showed that dietary lycopene intake increased the plasma and meat antioxidant vitamin E level (P<0.001), had a increased trend on muscle GSH (P=0.075). a*of meat was increased after seven days storage in lycopene groups, the levels of lipid oxidation were significantly inhibited with aging time extension in lycopene-supplemented groups. Scavenging abilities of superoxide anion and hydroxyl radical were increased compared to control groups. Experiment5:Effect of different levels of lycopene intake on antioxidant status and Nrf2/HO-1-mediated antioxidant protection mechanisms. The results showed that dietary lycopene intake increased activities of catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) of plasma, liver and muscle. In addition, dietary lycopene intake had an increased effect on the mRNA expression of Nrf2and CAT, but not on the mRNA expression of P450, HO-1, SOD1, SOD2, and GSH-Px. Experiment6: Antioxidant activities of lycopene in vitro. The results showed that lycopene could scavenge DPPH radical, hydroxyl radical and superoxide anion radical, and has a good dose-dependent effect, and its scavenging activities were superior to vitamin C. Therefore, lycopene show a very good antioxidant capacity in vitro. In summary, lycopene intake in summer improved oxidative status via activating host defense system, and thus enhanced the disease-resistance of animal, and thus improved the growth of Bamei sheep. In addition, dietary lycopene supplementation also improved the muscle development, reducing intramuscular fat deposition and increased polyunsaturated fatty acids content of meat, thereby improved the meat quality.