Evaluation of metabolic stress status in common carp (Cyprinus carpio) exposed to the fungicide folpet.

Among pesticides, fungicides are the most extensively used ones in agriculture and their effects on fish health and indirectly human health are needed to evaluate. Folpet has been used for over 50 years as a fungicide across the world. The mechanism of action of folpet on non-target aquatic organisms is so poorly understood and there is no available information about potential acute toxicity of folpet and its mechanism of action in non-target aquatic organisms. With this motivation, two successive experiments were set up: first, 96 h-LC50 value of folpet for common carp (Cyprinus carpio) was determined; and second, effects of different sublethal concentrations (0, 0.025, 0.50, 0.1 and 0.15 mg/L) of folpet on hematological serum biochemical blood parameters, DNA damages, expression levels of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), and cortisol receptor (HSP70) genes were evaluated in this study. It was calculated that 0.199 mg/L of folpet was the 96 h-LC50 value. After the folpet exposure for 14 days, significant decreases in red blood cells, hemoglobin, hematocrit, serum total protein, and GST gene expression levels were observed while serum glucose, liver enzymes activities, and expression levels of CAT, SOD, GPx, HSP70 genes increased. Also, folpet induced a significant genotoxic effect on the blood cells regarding to DNA damages. Consequently, the results have shown the toxic effects of folpet even at the lowest concentration on common carp.

The impact of acute cold water stress on blood parameters, mortality rate and stress-related genes in Oreochromis niloticus, Oreochromis mossambicus and their hybrids.

This study aims to evaluated the response of Oreochromissp. to cold stress. Two experiments were conducted involving a total of 1080 juvenile Oreochromis niloticus, O. mossambicus, O. niloticus♂ × O.mossambicus♀=F1♂ × O.mossambicus ♀ (Hybrid 1; H1) and O. mossambicus♂ × O. niloticus♀ (Hybrid 2; H2). In the 1st experiment, fish were exposed to cold water (12 °C) for 24 h and then hematological parameters, serum biochemical variables, innate immune responses, antioxidant status, and liver gene expression responses (hsp70, hsp27, hsp90, hsp40, cat, sod, eef1a1 and calreticulin) were analyzed. Hematological and serum biochemical responses involved species-specific differences. At optimal temperatures (28 °C), respiratory burts activity (RBA) and myeloperoxidase (MPO) values of H1, H2 and O. mossambicus were significantly higher than O. niloticus (p< 0.05). While the RBAvalue of O. mossambicus decreased after exposure to cold water (p< 0.05), lysozyme activities of O. niloticus and H2 and MPO activities of all experimental fish increased significantly (p< 0.05). At control conditions (28 °C), cortisol levels were found to be higher in O. mossambicus than in H1 and O. niloticus (p< 0.05). A significant increase in cat and sod transcripts was observed in liver of fish being very pronounced in O. mossambicus and H2. The highest up-regulation was observed for hsp70 target where the lowest but significant up-regulation was observed for hsp90 gene. In 2nd experiment, water temperature was gradually decrease from 28 °C to 12 °C (average, 1 °C/1 h).Survival rates of H1 and H2 were found to be different compared to O. mossambicus and O. niloticus (p< 0.05) after 20 days of cold water challenge.O. mossambicus was the most cold-sensitive group, followed by the H2, H1 and O. niloticus. Our data should be carfully considered in view of the possible physiological and anti-stressor responses being species-specific in fish.

Effects of subchronic exposure to phosalone on oxidative stress and histopathological alterations in common carp (Cyprinus carpio, L., 1758).

In this study, possible oxidative stress, biomarkers, and histopathological alterations were investigated in common carp (Cyprinus carpio, L., 1758) that were exposed to various phosalone concentrations in vivo. Fish were exposed to 0.15, 0.3, and 0.6 mg/L phosalone concentrations in a semistatic regime for 14 d. Biomarkers, including Na(+), K(+)-ATPase, reduced glutathione (GSH), thiobarbituric acid-reactive substances (TBARS), and histopathological changes, were determined in gills, liver, and kidney tissues of fish. Sublethal phosalone concentrations produced lipid peroxidation and impairment in the antioxidant defense system by increasing reactive oxygen species (ROS) production. While GSH increased in all groups at d 7 compared to control, GSH fell significantly at medium and high doses at d 14. Reduced GSH levels were diminished in all tissues and a significant induction in lipid peroxidation (TBARS) was observed. Na(+),K(+)-ATPase enzyme activity was significantly inhibited especially in gills. No histopathological effects were observed in the control group. Lamellar aneurysm, lamellar fusion, hyperplasia, epithelial lifting, and hemorrhages were observed in gill tissues exposed to phosalone. Histopathological effects in the liver tissues of fish exposed to phosalone were characterized by cytoplasmic vacuolation, congestion, hypertrophy, and nuclear degeneration. Hypertrophy, tubule degeneration, mononuclear cell infiltration, and dilation of glomerular capillaries were noted in kidney tissues exposed to phosalone. The results indicate that phosalone exposure adversely affected the health of the fish, attributable to oxidative stress.

Effect of dietary herbal supplements on some physiological conditions of Sea Bass Dicentrarchus labrax.

This study was conducted in order to investigate the effects of dietary thyme Thymus vulgaris, rosemary Rosmarinus officinalis,and fenugreek Trigonella foenum graecum as feed additives on total liver fat levels and biometric indices of Sea Bass Dicentrarchus labrax. Four isonitrogenous (48% crude protein) and isocaloric(21 kJ/g) diets were formulated to contain 0% (control), or 1% of thyme, rosemary, or fenugreek. In a 45-d feeding trial, 12 fiberglass tanks (140 L) were each stocked with 17 fish (20.43 ± 0.03 g).Herbal supplemented diets significantly decreased the total liver fat, visceral fat index, viscerosomatic index, hepatosomatic index,and increased the spleen­somatic index and bile­somatic index(P<0.05). In conclusion, the results indicated that a dietary level of1.0% for thyme, rosemary, or fenugreek could improve some of the physiological parameters of Sea Bass. Thus, this work provides anew perspective for the use of medicinal herbs that can be added to fish feed to improve the status of fish organs. Thyme, rosemary, and fenugreek contain a number of different active components, which possibly play an important role in improving these conditions, but the mechanism by which this is achieved needs further and more detailed study.