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Influences of dietary selenomethionine exposure on tissue accumulation, blood biochemical profiles, gene expression and intestinal microbiota of Carassius auratus

Bai, Zhuoan, Ren, Tongjun, Han, Yuzhe, Rahman, Md Mostafizur, Hu, Yanan, Li, Zequn, Jiang, Zhiqiang
Comparative biochemistry and physiology 2019 v.218 pp. 21-29
Carassius auratus, Ralstonia, Vibrio, alanine transaminase, alkaline phosphatase, antioxidant activity, aspartate transaminase, blood chemistry, blood serum, catalase, diet, dose response, fish, gene expression, gene expression regulation, genes, glutathione peroxidase, glutathione transferase, high-throughput nucleotide sequencing, hydrogen peroxide, insulin-like growth factor I, intestinal microorganisms, kidneys, liver, malondialdehyde, microbial communities, muscles, selenium, selenomethionine, somatotropin receptors, toxicity
A 30-days feeding trail was conducted to determine the sensitivity of Carassius auratus to the toxicological effects of elevated dietary Selenomethionine (Se-Met). C. auratus averaging 23.56 ± 1.82 g were exposed to four Se-Met concentrations (mg Se/kg): 0 (Se-Met0), 5 (Se-Met5), 10 (Se-Met10) and 20 (Se-Met20) to estimate the effects on tissue selenium (Se) accumulation, blood biochemical profiles, transcript expression and intestinal microbiota. Se accumulated in the kidney, liver and muscle in a dose-dependent manner and followed this order: kidney > liver > muscle, the highest accumulation were obtained in kidney of Se-Met20 diet after 30 days of feeding. Serum contents of alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) in fish exposed to Se-Met20 group was significantly highest among Se-Met exposure groups. Hydrogen peroxide (H2O2) concentrations in liver were affected by dietary Se-Met exposures. Liver contents of total antioxidant capacity (TAC), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) in fish exposure to Se-Met5 group was significantly highest among Se-Met exposure groups. Growth hormone receptor (GHR), insulin-like growth factor 1 (IGF-1) and antioxidant enzyme related genes including glutathione peroxidase (GPx), catalase (CAT) and glutathione S-transferase (GST) expression in liver were down-regulated with the concentration of Se-Met exposure groups. The results of high-throughput sequencing showed that gut microbial communities and hierarchy cluster heatmap analysis were significantly affected by Se-Met exposure. The abundances of Cetobacterium and Vibrio increased while fish exposed to Se-Met20 group. The abundance of Ralstonia increased when the Se-Met exposure dose reached 10 mg Se kg−1. The results suggested that the exposure to elevated dietary Se-Met may result toxic effects in C. auratus.