Goose fat, a promising nutrient for fish feeding, activates antioxidant enzymes in rainbow trout, Oncorhynchus mykiss.

The objective of this experiment was to test effects of different dietary lipids in rainbow trout feeding on the activity and expression of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione S-transferase (GST). Four iso-nitrogenous and iso-lipidic casein-gelatin based experimental diets were formulated. The sources of dietary lipids were cod liver oil (CO, rich in polyunsaturated fatty acids), goose fat (GF, rich in saturated fatty acids and monounsaturated fatty acids), soybean oil (SO, rich in linoleic acid), and a blend of CO, GF and SO. Dietary treatments had no significant effect on growth performance and survival was not affected. SOD, GPx and GST enzymes had the maximum activity in GF diet. However qPCR data showed that SOD and GPx mRNA levels were minimum in GF group. Overall data showed that rainbow trout liver enzymes were activated upon GF diet probably activating the enzyme structure itself without stimulating gene expression.

Alterations in fatty acids of polar lipids in Salmo trutta on long-term exposure to a glyphosate-based herbicide (Roundup).

Abstract: In present study, the effects of sublethal doses (10 and 20 mg L(-1)) of Roundup on fatty acid pattern in muscle and liver of brown trout were investigated. For this purpose, fish were held in experiment tanks for 1 month. While total MUFA wasn't influenced, the highest total SFA and total n-6 PUFA were determined in group 10 mg L(-1) and the lowest values were determined in control group and group 20 mg L(-1) in muscle, respectively. The highest and the lowest total n-3 PUFA was found in control group and group of 10 mg L(-1) in muscle, respectively. Total n-3/n-6 PUFA ratio and EPA+DHA level of group 10 mg L(-1) were lower than other groups in muscle. The amount of total n-3/n-6 PUFA, EPA + DHA and total n-3 PUFA of control group were found higher than treatment groups in liver. While the highest total SFA was determined in group 10 mg L(-1), there wasn't difference between control group and group 20 mg L(-1) in liver. Both of doses herbicide had higher value than control for total MUFA in liver. While Roundup didn't inhibit n-3 PUFA synthesis in the muscle, both concentrations, exhibited inhibitory effect on n-3 PUFA synthesis in the liver. This result probably consequence of its indirect effect on the some enzyme activities or gene expressions in fatty acid metabolism of brown trout.