Risk assessment of glyphosate and malathion pollution and their potential impact on Oreochromis niloticus: role of organic selenium supplementation.

A field survey was conducted on five fish farms to trace glyphosate and malathion pollution with some physicochemical parameters. A precise half-life time, LC50-96h, of these agrochemicals on Oreochromis niloticus, as well as chronic exposure with organic selenium (OS) supplementation, were experimentally investigated. Oreochromis niloticus was subjected to the following: (negative control); (2 mg L-1 glyphosate); (0.5 mg L-1 malathion); (glyphosate 1.6 mg L-1 and 0.3 mg L-1 malathion); (glyphosate 2 mg L-1 and OS 0.8 g kg-1 diet); (malathion 0.5 mg L-1 and OS 0.8 g kg-1 diet) and (glyphosate 1.6 mg L-1; malathion 0.3 mg L-1 and OS 0.8 g kg-1 diet). Furthermore, data from the analyzed pond revealed a medium risk quotient (RQ) for both agrochemicals. The detected agrochemicals were related to their application, and vegetation type surrounding the farms, also their biodegradation was correlated to water pH, temperature, and salinity. Glyphosate and malathion had half-lives of 2.8 and 2.3 days and LC50-96h of 2.331 and 0.738 mg L-1, respectively. The severest nervous symptoms; increased oxidative stress markers, as well as high bacterial count in the livers and kidneys of fish challenged with Aeromonas hydrophila, were observed in the combined exposure, followed by a single exposure to malathion and then glyphosate. Organic selenium mitigated these impacts.

Ameliorative effect of selenium yeast supplementation on the physio-pathological impacts of chronic exposure to glyphosate and or malathion in Oreochromis niloticus.

BACKGROUND: Pesticide exposure is thought to be a major contributor to living organism health deterioration, as evidenced by its impact on both cultured fish species and human health. Commercial fish diets are typically deficient in selenium (Se); hence, supplementation may be necessary to meet requirements during stress. Therefore, this study was conducted to investigate the protective role of selenium yeast (SY) supplementation for 60 days against the deleterious effects of glyphosate and or malathion chronic toxicity at sublethal concentrations in Oreochromis niloticus . METHODS: Two hundred and ten fish were divided into seven groups (n = 30/group) as follows: G1 (negative control); G2 (2 mg L- 1 glyphosate); G3 (0.5 mg L- 1 malathion); G4 (glyphosate 1.6 mg L- 1 and malathion 0.3 mg L- 1); G5 (glyphosate 2 mg L- 1 and SY 3.3 mg kg- 1); G6 (malathion 0.5 mg L- 1 and SY 3.3 mg kg- 1); and G7 (glyphosate 1.6 mg L- 1; malathion 0.3 mg L- 1 and SY 3.3 mg kg- 1). RESULTS: Results revealed significant alteration in growth performance parameters including feed intake (FI), body weight (BW), body weight gain (BWG), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER). G4 has the highest documented cumulative mortalities (40%), followed by G3 (30%). Additionally, the greatest impact was documented in G4, followed by G3 and then G2 as severe anemia with significant thrombocytopenia; leukocytosis; hypoproteinemia; increased Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST), urea, and creatinine, as well as malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx). Considering the previously mentioned parameters, selenium yeast (Saccharomyces cerevisiae) (3.3 mg kg- 1 available selenium) mitigated the negative impact of both the agrochemicals, whether exposed singly or in combination, in addition to their antioxidative action. CONCLUSIONS: In conclusion, our study found that organophosphorus agrochemicals, single or combined, had negative impacts on Oreochromis niloticus regarding growth performance, biochemical and hematological changes in the serum, as well as induced oxidative damage in liver and kidney tissues. Supplementation of SY at the rate of 3.3 mg kg- 1 diet (2.36 mg kg- 1 selenomethionine and 0.94 mg organic selenium) ameliorated the fish performance and health status adversely affected by organophosphorus agrochemical intoxication.

Effects of bovine lactoferrin and chitosan nanoparticles on serum biochemical indices, antioxidative enzymes, transcriptomic responses, and resistance of Nile tilapia against Aeromonas hydrophila.

The present study was carried out to investigate the effects of dietary bovine lactoferrin (BLF) or chitosan nanoparticles (CHN) alone or in combinations on serum biochemical indices, antioxidative capacity, transcriptomic responses, non-specific immunity, and resistance of Nile tilapia (Oreochromis niloticus) against challenge with Aeromonas hydrophila. Fish were fed on the basal diet with no supplements and served as control (CTR), and six other experimental diets containing different levels of BLF (800 and 1200 mg per kg diet), CHN (500 and 1000 mg per kg diet), and their combinations (400 mg BLF plus 250 mg CHN per kg diet, and 600 mg BLF plus 500 mg CHN per kg diet) for 45 days. At the end of the experiment, serum, and tissue specimens (liver and kidney) were collected, fish in all groups were challenged with A. hydrophila and then observed for another ten days to calculate the RPS. Compared to the CTR group, no significant differences were recorded in TP, ALB, GLO, BUN, and CREAT values among all treatments. Serum LYZ, ALT, AST, and ALP enzyme activities were significantly increased in all experimental groups over the CTR (P < 0.05), and their highest values were recorded in the combined treatments. Moreover, dietary supplementation with CHN (1000 mg/kg) and combined treatments significantly increased the SOD, CAT, and GSH-Px enzyme activities compared to other groups (P < 0.05). The highest mRNA expression levels of IGF-1 gene in liver, and IL-1ß, and IFN-γ genes in kidneys were found in CHN (1000 mg/kg) group and combined treatments more than other groups. Interestingly, no, or mild histopathological alterations were noticed in the hepatopancreas and posterior kidney of the treated groups. A significantly higher RPS was identified in the combined treatments challenged with A. hydrophila compared with the CTR group. This study exemplifies the positive impacts of dietary supplementation with BLF or CHN alone or combinations on the antioxidative status, immunity, and disease resistance of Nile tilapia.