emamectin-benzoate and Body-Weight

Emamectin benzoate (EB) is an avermectin insecticide used extensively in pest control on vegetable and field crops. Few studies have been done for evaluating adverse effects of EB. In the current study, we evaluated the toxic effects of EB on male rats and the possible ameliorative role of fennel essential oil (FEO). Thirty two male rats were randomly divided into 4 equal groups. All groups were treated orally with distilled water (control group), 0.5mlFEOkg(-1) BW (FEO group), 2.5mgEBkg(-1) BW (EB group), and 0.5mlFEOkg(-1) BW+2.5mgEBkg(-1) BW (FEO+EB group) for 28 days. The obtained results showed that EB treatment resulted in a significant decrease in body weight, body weight gain, RBC count, Hb concentration, % PCV, MCV and MCHC. Moreover, EB significantly decreased total leukocyte, lymphocyte, monocyte and platelet count but significantly increased granulocyte count. EB markedly decreased total protein, albumin, globulin, IgG and IgM concentrations with a significant increase in TNF-α secretion. EB had a negative impact on the liver as it significantly increased ALT, ALP, and MDA, while decreasing SOD activity. Regarding to the histopathological examination, EB treatment induced coagulative necrosis and blood vessels congestion of the liver in treated rats. Furthermore, it resulted in depletion and necrosis of the white pulp of the spleen in treated rats. The co-administration of FEO with EB, however, improved the majority of parameters studied, suggesting that FEO is an important substance in decreasing toxic effects of EB.

Topics: Administration, Oral; Animals; Biomarkers; Body Weight; Chemical and Drug Induced Liver Injury; Foeniculum; Ivermectin; Male; Oils, Volatile; Rats; Toxicity Tests, Subchronic; Weight Gain

The impact of salmon lice on the survival of migrating Atlantic salmon smolts was studied by comparing the adult returns of sea-ranched smolts treated for sea lice using emamectin benzoate or substance EX with untreated control groups in the River Dale in western Norway. A total of 143 500 smolts were released in 35 release groups in freshwater from 1997 to 2009 and in the fjord system from 2007 to 2009. The adult recaptures declined gradually with release year and reached minimum levels in 2007. This development corresponded with poor marine growth and increased age at maturity of ranched salmon and in three monitored salmon populations and indicated unfavourable conditions in the Norwegian Sea. The recapture rate of treated smolts was significantly higher than the controls in three of the releases performed: the only release in 1997, one of three in 2002 and the only group released in sea water in 2007. The effect of treating the smolts against salmon lice was smaller than the variability in return rates between release groups, and much smaller that variability between release years, but its overall contribution was still significant (P < 0.05) and equivalent to an odds ratio of the probability of being recaptured of 1.17 in favour of the treated smolts. Control fish also tended to be smaller as grilse (P = 0.057), possibly due to a sublethal effect of salmon lice.

Topics: Animals; Body Size; Body Weight; Copepoda; Ectoparasitic Infestations; Fish Diseases; Ivermectin; Norway; Salmo salar; Sexual Maturation

The potential impact of commercial salmon aquaculture along the coast of British Columbia on the health of non-target marine wildlife is of growing concern. In the current initiative, the biological effects on gene expression within spot prawn (Pandalus platyceros) exposed to the sea lice controlling agent, emamectin benzoate (EB; 0.1-4.8 mg/kg sediment), were investigated. A mean sediment/water partitioning coefficient (K(p)) was determined to be 21.81 and significant levels of EB were detected in the tail muscle tissue in all exposed animals. Animals selected for the experiment did not have eggs and were of similar weight. Significant mortality was observed within 8 days of EB treatment at concentrations between 0.1 and 0.8 mg/kg and there was no effect of EB on molting. Twelve spot prawn cDNA sequences were isolated from the tail muscle either by directed cloning or subtractive hybridization of control versus EB exposed tissues. Three of the transcripts most affected by EB exposure matched sequences encoding the 60S ribosomal protein L22, spliceosome RNA helicase WM6/UAP56, and the intracellular signal mediator histidine triad nucleotide binding protein 1 suggesting that translation, transcription regulation, and apoptosis pathways were impacted. The mRNA encoding the molting enzyme, β-N-acetylglucosaminidase, was not affected by EB treatment. However, the expression of this transcript was extremely variable making it unsuitable for effects assessment. The results suggest that short-term exposure to EB can impact biological processes within this non-target crustacean.

Topics: Animals; Antiparasitic Agents; Body Weight; Gene Expression Profiling; Gene Expression Regulation; Ivermectin; Muscles; Pandalidae; RNA, Messenger; Water Pollutants, Chemical