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.

Metabolic responses to prolonged starvation, food restriction, and refeeding in the brown trout, Salmo trutta: oxidative stress and antioxidant defenses.

The effects of long-term starvation and food restriction (49 days), followed by refeeding (21 days) have been studied with respect to antioxidant defense in the liver and gills (branchial tissues) of the brown trout, Salmo trutta. Malondialdehyde levels in both tissues increased in parallel with starvation and food restriction and these values did not return to normal after the refeeding period. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in liver and gills increased during the 49 days of starvation, but glucose-6-phosphate dehydrogenase (G6PD) activities decreased. Glutathione S-transferase (GST) activity decreased in the liver at the 49th day of starvation, but increased in the branchial tissues. Some of the antioxidant enzyme activities (such as hepatic GST and branchial G6PD) returned to control values of fed fish after the refeeding period, but others (e.g. hepatic SOD and branchial GPx) did not return to normal values. In conclusion, our study indicates that total or partial food deprivation induces oxidative stress in brown trout.