The effects of coated inorganic trace minerals on the growth performance, mineral retention, and intestinal health comparing with inorganic and organic trace minerals for juvenile American eels (Anguilla rostrata)

This study was conducted to compare the effects of coated inorganic trace minerals (CITM) with those of inorganic and organic trace minerals on the growth performance, mineral retention in the whole-body, and intestinal health of juvenile American eels ( Anguilla rostrata ). Eels were randomly divided into the inorganic trace minerals (ITM) group, organic trace minerals (OTM) group, coated inorganic trace minerals I (CITM I) group, and coated inorganic trace minerals II (CITM II) group, respectively. The supplementation level of trace minerals in the CITM II group was 50 % of those in the CITM I group. Eels were fed experimental diets for ten weeks. Compared with the ITM group, weight gain rate, specific growth rate, protein efficiency, and feed efficiency of those in the CITM I and CITM II groups were increased. Eels in the CITM I group exhibited higher retention rates of calcium, phosphorus, and zinc in whole body than those in the ITM and OTM groups. CITM I group displayed the increased levels of high-density lipoprotein cholesterol, immunoglobulin M, and D-lactic acid compared to the ITE group. Compared with the ITM and OTM groups, CITM I and CITM II groups showed enhanced intestinal histology and activities of intestinal amylase, lipase, and glutathione peroxidase (GSH-Px), coupled with an increase of GSH content. Proteome analysis demonstrated that, compared to the ITE group, CITM I group displayed enhanced intestinal protein abundance associated with vitamin digestion and absorption, fat digestion and absorption, cysteine and methionine metabolism, and amino acid biosynthesis. In conclusion, CITM is more beneficial for the growth performance, mineral retention in the whole-body, and intestinal health of juvenile American eels compared to ITM and OTM sources. Our findings provide valuable insights into the application of the coated trace minerals sources in the diets for American eels and potentially for other fish species. • Dietary supplementation with OTM and CITM improved the growth performance, mineral retention, and immunity of American eels. • Dietary CITM enhanced intestinal histology, digestive enzyme activity, and antioxidant capacity of American eels. • CITM promoted the digestion and absorption of vitamins and fats, as well as the metabolism of amino acids, in the intestine.