Protection Of Silymarine To Liver Injury Of Megalobrama Amblycephala Induced By Oxidized Oil

Test1: In the artificial oxidation conditions, we measured acid value, iodine value,peroxide value, MDA and fatty acids of lard, soybean oil, rapeseed oil, cottonseed oilfrom Jiangsu and Xinjiang,tilapia oil, soybean meal and rapeseed meal.Results:①Changes of the measured oxidation indicators of tilapia oil were more obvious thanother oil, which meant tilapia oil was the worst oxidation stability;②The indicator POVof lard, tilapia oil, cottonseed oil, rapeseed oil and soybean oil obviously changed in theoxidation process, therefore it should become the common evaluation indicator;③Changes of the oxidation indicators of soybean meal and rapeseed meal were thesmallest, and the oxidative stability was obviously better than their corresponding oil;④During the70hours period, with the extention of oxidation time, the fatty acidcomposition of the oil hadn’t obviously change. Conclusion: In the oxidation process,sensitive indicators of different types of fat are different. To evaluate oil oxidation, theindicators should be selected according to each type of fat. In the early stage of oiloxidation, it is not obvious to characterize the quality of the oil with the change of fattyacid composition.Test2: The purpose of this study was focused on the damage of oxidized soybeanoil to the liver of megalobrama amblycephala and the protection effect of silymarine,meanwhile, define the appropriate dosage in the feed initially. Experiment was dividedinto oxidized soybean oil group and soybean group according to whether the soybeanoil be oxidized or not in feed.0mg/kg(control group),5mg/kg,10mg/kg,50mg/kgsilymarine were added into the experimental diets respectively. There were eightexperimental groups, each with three replicates.480fish(initial weight:31.00±0.60g)were randomly divided into24cages, hanged in the indoor concrete ponds, and20fishin each cage were fed for8weeks. We analysed the growth performance, biochemicalindicator and the structure of liver and intestinal tract.The results showed that:①Theweight gain rate was decreased and feed coefficient was increased significantly(P＜ 0.05); Compared to the control group, weight gain rate of50mg/kg silymarine groups ofoxidized soybean oil group and soybean oil group were increased significantly (P＜0.05), and feed coefficient was decreased in oxidized group (P＞0.05).②Afteroxidized soybean oil being added, content of Hb and serum Alb, activity of SOD andGSH-Px in liver were decreased and serum GOT, Glo increased significantly (P＜0.05);Serum HDL-C decreased, and serum GPT, CHO and TRIG increased, but notsignificantly (P＞0.05); In the oxidized soybean oil group, Hb, SOD and GSH-Px ofliver, serum HDL-C, Alb increased and serum GOT, CHO, TRIG and Glo decreasedalong with rise of silymarine level.③After oxidized soybean oil being added, crude fatof liver increased significantly. Moreover, we found that there were lots of fat droplet inthe hepatocyte and density of the hepatocyte decreased by tissue slice of liver. Aftersilymarine was added, content of crude fat, fat droplet in liver were decreased anddensity of hepatocyte was increased gradually. Liver was protected when the silymarinelevel was50mg/kg. The damage of oxidized soybean oil and protection of silymarine tothe intestinal microvilli somewhat analogous to the liver.The results suggest that: The growth performance of megalobrama amblycephalawas decreased after oxidized soybean oil being added in the feed, meanwhile, proteinanabolism and lipid metabolism of liver, structure of liver and intestinal tract were alsodamaged. In the condition of this experiment, the silymarine level of50mg/kg willincrease the growth performance of megalobrama amblycephala in both the oxidizedgroup and non-oxidized group(P＜0.05), repair the oxidation resistance and metabolicfunctions and structure of the liver efficiently, although, there was negative effect forthe physiology of non-oxidized group.Test3: The purpose of the experiment was focused on vicarious function of themilk thistle seed to silymarine in the feed of megalobrama amblycephala. Diets weredivided into silymarine group and milk thistle seed group, in which containing the samelevels of the silymarine of5mg/kg,10mg/kg,50mg/kg and0mg/kg as the commoncontrol group. There are7groups, each with three replicates,420fish(initial weight:31.00±0.60g) were randomly divided into21cages, hanged in the indoor concreteponds, and20fish in each cage were fed for8weeks. We analysed the growthperformance, biochemical indicator and the structure of liver and intestinal tract. The results showed that:①Compared to the control group, the weight gain rate increasedalong with level of milk thistle seed rise, but not significantly. Between silymarinegroup and milk thistle seed group, there was no significant change.②Compared to thecontrol group, serum glucose and GOT decreased significantly, serum SOD and HDL-Cincreased significantly(P＜0.05)in the50mg/kg milk thistle seed group; the Hb, serumAlb increased and serum GPT decreased along with rise of milk thistle seed level, butnot significantly(P＞0.05). Compared to the silymarine group, content of Hb increasedand serum GOT decreased significangtly in50mg/kg milk thistle seed group(P＜0.05).③There was no obvious difference about structure of liver and intestinal tract betweensilymarine group and milk thistle seed group.The results suggest that: In the condition of this experiment, milk thistle seed isgood for the growth performance,antioxidation and metabolic functions of the liver.There was no significant difference about the growth,antioxidation and metabolicfunctions of the liver at the same level of silymarine and milk thistle seed. Theappropriate of milk thistle seed was50mg/kg, which could supersede the function ofsilymarine.