Ercüment Aksakal

Acute and long-term genotoxicity of deltamethrin to insulin-like growth factors and growth hormone in rainbow trout

We report here the acute and long-term influences of deltamethrin on the expression of IGF-I, IGF-II and GH-I in rainbow trout muscles. We treated rainbow trouts with different concentrations of deltamethrin (0.25 microg/L, 1 microg/L and 2.5 microg/L) and observed the alterations in mRNA expression levels of IGF-I, IGF-II and GH-I at different time intervals (at 6th, 12th, 24th, 48th, 72nd hours and 30th day). The mRNA levels significantly decreased with increasing deltamethrin concentrations for acute administration. Interestingly, a significant recovery in GH-I expression was seen after the 72nd hour up to 30th day while no significant differences were observed for IGF-I and IGF-II between the same time intervals. Here we demonstrate that deltamethrin exposure decreases the expression of IGF-I, IGF-II and GH-I in rainbow trout which might cause undesirable outcomes not only in growth, but also in development and reproduction.

The effect of peptide absorption on PepT1 gene expression and digestive system hormones in rainbow trout (Oncorhynchus mykiss).

The present study evaluates the effect of protein source (dipeptides, free amino acids, and intact protein) on development and growth of Salmonid fish alevin. Specifically, we follow the expression of oligopeptide transporter protein PepT1 in the intestine of rainbow trout (Oncorhynchus mykiss). Fish were fed exogenously one of four diets: three formulated (lysyl-glycine dipeptide supplemented diet - PP, free lysine and glycine supplemented diet - AA, control diet with no lysine - CON) or commercial starter (Aller Futura - AF). Fish increased mean body weight 8 fold with PP- and AA-supplemented diets resulting in significantly higher weight gain than fish fed CON. Statistical analysis revealed a significant increase in relative PepT1 expression of fish fed experimental diets. Immunohistochemical staining with PepT1 antibody showed the presence of the transporter protein in the brush border membrane of the proximal intestinal enterocytes of fish from all experimental groups. Leptin immunoreactivity occurred not only in the gastric glands but also in proximal intestine and pyloric caeca of fish fed PP, AA and AF diets. Leptin immunoreactivity was also observed in hepatocyte cytoplasm and pancreatic acinar cells. Gastrin/CCK immunoreactive cells were present in the proximal intestine and pyloric caeca.

Impact of deltamethrin exposure on mRNA expression levels of metallothionein A, B and cytochrome P450 1A in rainbow trout muscles

Metallothioneins (MT) are widely utilized to identify specific responses to heavy metal pollution. In addition, there is evidence demonstrating that in vertebrates MT synthesis is stimulated by different endogenous and exogenous agents in particular compounds leading to production of ROS. Also, cytochrome P450 1A can enhance the generation of ROS. On this basis, MT and CYP 1A induction can be considered as biomarkers of oxidative stress. In the current study, we examined the influences of pesticide administration on the expression of MT-A, MT-B and CYP 1A. For this purpose, we produced muscle metallothionein-A, metallothionein-B and cytochrome P450 1A cDNAs and used quantitative RT-PCR to assay mRNAs in rainbow trout exposed to acute and long-term deltamethrin administration. We observed that deltamethrin exposure significantly (p<0.05) increased the expression levels of Cyp1A, MT-A and MT-B in a time dependent manner. Results of our study contributes to the identification of inducers of such biomarkers in addition to well known agents.

Seasonal changes in antioxidant defence system of liver and gills of Salmo trutta caspius, Salmo trutta labrax and Salmo trutta macrostigma

Seasonal changes in antioxidant enzyme activities (superoxide dismutase, SOD, EC 1.15.1.1; catalase, CAT, EC 1.11.1.16; glutathione peroxidase, GPx, EC 1.11.1.9; glutathione reductase, GR, EC 1.6.4.2; glucose-6-phosphate dehydrogenase, G6PD, EC 1.1.1.49 and glutathione S-transferase, GST, EC 1.5.1.18) and lipid peroxidation (LPO) levels of livers and gills of female Caspian trout Salmo trutta caspius, Black Sea trout Salmo trutta labrax and mountain trout Salmo trutta macrostigma were investigated. SOD, CAT, GPx, G6PD and GST activities were higher in liver compared to gills of all sub-species; concomitantly, the GR activity was also higher in the livers of S. t. caspius and S. t. labrax, but the reverse was seen in S. t. macrostigma. LPO levels were higher in the gills compared to the liver of all sub-species. There was no general trend in the seasonal changes in the gill antioxidant enzyme (AE) activities or LPO levels. Higher AE activities, however, were found in the liver of each sub-species during autumn, and this coincided with an increase in the gonado-somatic index.

Chronic toxicity of pesticides to the mRNA expression levels of metallothioneins and cytochrome P450 1A genes in rainbow trout

The hazardous effects of pesticides on various metabolic pathways are a great problem for environmental health and should be well determined. In the present study, the authors treated rainbow trout with 0.6 μg/L deltamethrin for 28 days and 1.6 mg/L 2,2-dichlorovinyl dimethyl phosphate for 21 days. After this time period, the authors observed alterations in mRNA expression levels of MT-A, MT-B and CYP-1A. Chronic exposure to low levels of pesticides may have a more significant effect on fish populations than acute poisoning. While both pesticides caused a significant increase on mRNA levels of MT-A and CYP-1A, MT-B mRNA levels were increased significantly only upon deltamethin administration. The significant increase in mRNA levels of the corresponding genes may be considered as a defence mechanism in addition to the antioxidants against oxidative stress, as well as a detoxification mechanism against adverse effects of pesticides.

Influence of pesticides on the pH regulatory enzyme, carbonic anhydrase, from European Seabass liver and bovine erythrocytes.

The objective of this study was to assess the inhibitory effects of six commonly used pesticides, cyhalothrin, cypermethrin, dichlorvos, methamidophos, chlorpyrifos and methylparathion, on the pH regulatory enzyme carbonic anhydrase (CA) of Dicentrarchus labrax (European Seabass) liver (dCA) and bovine erythrocytes (bCA). Results of the study showed that the pesticides displayed quite variable inhibition profiles with K(I) values ranging from 0.376 to 26.164μM against dCA, and from 1.174 to 53.281μM against bCA. Methylparathion was the most effective inhibitor for both enzymes. Overall data show that all of the tested pesticides inhibit both dCA and bCA at low concentrations indicating that indiscriminate use of these pesticides might cause disruption of acid base regulation resulting in animal deaths. Our results also point out that susceptibility to these pesticides varies among CAs from different organisms.

Effect of dietary fish oil replacement with plants oils on growth performance and genes expression in juvenile rainbow trout (Oncorhynchus mykiss)

Abstract An eight-week feeding trial was conducted to evaluate the effects of total (100%) replacement of dietary fish oil with alternative lipid sources in juvenile rainbow trout. Six iso-nitrogenous and iso-lipidic experimental diets were formulated: CO (14%) – cod liver oil; SSO (14%) – safflower seed oil; SBO (14%) – soybean oil; LO (14%) – linseed oil; SBO (7%) + LO (7%) – a blend of soybean oil and linseed oil; and SSO (7%) + LO (7%) – a blend of safflower seed oil and linseed oil. Growth performance [specific growth rate (SGR), weight gain (WG), food conversion ratio (FCR) and survival rate (SR)], growth hormones [growth hormone (GH-I), insulin-like growth factor-I (IGF-I) and insulin-like growth factor-II (IGF-II)], immune transforming growth factor-β (TGF-β) and antioxidant [superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT) and glutathione S-transferase (GST)] response, and heat shock protein 70 (HSP70) mRNA levels were determined in muscle and liver. Our data indicated that final weight, weight gain, FCR and SGR showed significant difference among the six dietary treatments (P<0.05) while there were no significant differences in survival rate between the rainbow trout from supplement fed groups and control group. HSP70 mRNA level expression in muscle was higher in fish fed SSO (P<0.05) while highest level in liver was obtained from fish fed SBO compared to the other treatments (P<0.05). There were no significant differences among treatments for TGF-β mRNA expression level in muscle and liver. In conclusion, growth performance and expression levels of growth hormones, antioxidants, HSP70, except TGF-β were affected by five separate lipid sources. In addition, LO positively increased growth performance of juvenile rainbow trout by means of preventing oxidative stress and HSP70 and, enhanced expression of growth hormone related gene.