Efeitos da L-carnitina e de fontes lipídicas na dieta sobre o status antioxidante de matrizes e reprodutores de jundiá

Abstract

This study aimed to evaluate the effect of diets with inclusion of L-carnitine and different lipid sources, on blood biochemical parameters, activity of antioxidant enzymes and the histology of liver and gonads of jundiá broodstocks. Males and females of jundiá (n=360; 167.33 ± 9.24 g) were distributed in a 4x2 bi-factorial experimental design, with diets containing four levels of inclusion of L-carnitine (0, 150, 450, 750 mg kg-1 feed) and two lipid sources (soybean oil and marine fish oil), totaling eight treatments with three repetitions. Fish were fed on these diets, isoproteic (36.2% crude protein) and isoenergetic (3,188.9 kcal digestible energy kg-1) for 153 days. Glucose, triglycerides, cholesterol, high-density lipoprotein (HDL), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and plasma albumin were analyzed. Liver and gonads were analyzed for histology and activity of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST). For females, diets with 750 mg L-carnitine resulted in higher levels of glucose. The diet with 450 mg L- carnitine combined with soybean oil led to higher levels of triglycerides, cholesterol, HDL, and higher SOD activity in the liver. The diet with 150 mg L-carnitine combined with fish oil led to lower ALT and higher albumin. Diets with 150 mg L-carnitine resulted in higher AST. GST activity was not different between treatments. According to the histology of the ovaries, all females were able to spawn, with no difference in the percentage of vitellogenic oocytes. Liver had normal liver tissue, without the presence of vacuoles. For males, the diet with 750 mg L- carnitine combined fish oil led to the lowest mean value of HDL and higher mean levels of plasma glucose and SOD activity in testicles. The highest cholesterol level was found with diets containing 150 mg L-carnitine. Diets containing fish oil provided animals with higher mean values for glucose, triglycerides, cholesterol, ALT and albumin, and lower AST. There was no effect of diets on the activity of antioxidant enzymes in the liver. According to histological analysis, all males were able to spermiate, and their liver cells showed no vacuoles. The supplementation with 450 mg L-carnitine kg-1 feed, combined with soybean oil, can alter the lipid metabolism and positively influence the antioxidant status of jundiá females, and the combination of 750 mg L-carnitine kg-1 feed and fish oil can positively influence the antioxidant status of jundiá males.