Modulation of toxic effects of ammonia on growth, pathology of liver and kidney tissues and relative expression of GH and IGF-1 Genes by CoQ10 Supplementation in Oncorhynchus mykiss.

Reducing the negative impact of environmental and stressful factors is a crucial step in achieving sustainable aquaculture. Therefore, a study was aimed at evaluating the impacts of Coenzyme Q10 (CoQ10) supplementation on growth, relative gene expression of Growth Hormone (GH) and Insulin-like growth factor-1 (IGF-1), liver and kidney histopathology against stress induced by ammonia in Rainbow trout (Oncorhynchus mykiss). The fish were given feed containing different levels of CoQ10 for 8 weeks: Control - CoQ10 0%, G1 - CoQ10 0.1%, G2 - CoQ10 0.5% and G3 - CoQ10 1%. At the end of the experiment, fish were exposed to ammonia stress concentration at 0.6mg/L for 24 h to assess liver and kidney tissue damage. Results showed that there was a significant activity increase in GH and IGF-1 genes due to supplementation with CoQ10 alone (p < 0.05). Gene expression for GH increased about two-fold whereas that for IGF-1 experienced a four-fold upregulation compared to controls (p < 0.05). CoQ10's-related antioxidant effects probably minimized liver and kidney cellular injuries, as significant decreases were observed in ammonia-induced mortality (p < 0.05). In summary, adding CoQ10 to the diet is a potential way to improve fish production through controlling the gene expression of GH and IGF-1, as well as making fish populations more resistant to possible future stress caused by ammonia in intensive or super-intensive aquaculture systems.

Chestnut Shell Tannins: Effects on Intestinal Inflammation and Dysbiosis in Zebrafish.

The aim of the present study was to test the possible ameliorative efficacy of phytochemicals such as tannins on intestinal inflammation and dysbiosis. The effect of a chestnut shell (Castanea sativa) extract (CSE) rich in polyphenols, mainly represented by tannins, on k-carrageenan-induced intestinal inflammation in adult zebrafish (Danio rerio) was tested in a feeding trial. Intestinal inflammation was induced by 0.1% k-carrageenan added to the diet for 10 days. CSE was administered for 10 days after k-carrageenan induced inflammation. The intestinal morphology and histopathology, cytokine expression, and microbiota were analyzed. The k-carrageenan treatment led to gut lumen expansion, reduction of intestinal folds, and increase of the goblet cells number, accompanied by the upregulation of pro-inflammatory factors (TNFα, COX2) and alteration in the number and ratio of taxonomic groups of bacteria. CSE counteracted the inflammatory status enhancing the growth of health helpful bacteria (Enterobacteriaceae and Pseudomonas), decreasing the pro-inflammatory factors, and activating the anti-inflammatory cytokine IL-10. In conclusion, CSE acted as a prebiotic on zebrafish gut microbiota, sustaining the use of tannins as food additives to ameliorate the intestinal inflammation. Our results may be relevant for both aquaculture and medical clinic fields.