How Different Dietary Methionine Sources Could Modulate the Hepatic Metabolism in Rainbow Trout?

Abstract

In aquafeeds in which plant proteins are used to replace fishmeal, exogenous methionine (Met) sources are demanded to balance the amino acid composition of diets and meet the metabolic fish requirements. Nonetheless, since different synthetic Met sources are commercially available, it is important to determine their bioavailability and efficacy. To address this issue, we conducted a two-month feeding trial with rainbow trout (Oncorhynchus mykiss), which were fed diets supplemented with five different forms of Met: Met-Met, L-Met, HMTBa, DL-Met, and Co DL-Met. No differences in growth performance were found in trout fed with different Met forms, but changes in the whole-body composition were found. In particular, Met-Met and L-Met promoted a significant body lipid reduction, whereas the protein retention was significantly increased in fish fed with HMTBa and Co DL-Met. The latter affected the hepatic Met metabolism promoting the trans-sulfuration pathway through the upregulation of CBS gene expression. Similarly, the L-Met enhanced the remethylation pathway through an increase in BHMT gene expression to maintain the cellular demand for Met. Altogether, our findings suggest an optimal dietary intake of all tested Met sources with similar promoting effects on fish growth and hepatic Met metabolism. Nevertheless, the mechanisms underlying these effects warrant further investigation.

Genome‐wide insights into whole gut microbiota of rainbow trout, Oncorhynchus mykiss, fed plant proteins and camelina oil at different temperature regimens

“…Interestingly, our results showed a significant increase in levels of genes involved in methionine and cysteine metabolism in fish fed plant ingredients (100% PP, 100% CO) than those fed animal‐rich diet (100% AP, 50% FO, 50% CO). These findings contradict earlier reports that animal diets have higher levels of methionine than plant‐based diets (Ceccotti et al, 2022; Nguyen et al, 2019). It is possible that the gut microbiota of rainbow trout raised on plant ingredients may have utilized the supplemental methionine more efficiently or added methionine created an enrichment culture for the bacteria that can feed on it or the level of methionine in plant‐based diets exceeded the levels contained in animal‐based diets; however, the exact concentration of methionine in these diets was not determined.…”

Dietary Effect of S-Methylmethionine Sulfonium Chloride on Growth, Serum Biochemical Parameters, Body Composition, and Expression of Some Related Genes in Oreochromis niloticus

“…It is produced biologically from L-methionine and S-adenosylmethionine by the enzyme methionine Smethyltransferase in hepatocytes (Bradbury et al, 2014). Moreover, methionine or its derivatives were shown to be an important amino acid in most of plant ingredients applied into fish feed (Ceccotti et al, 2022). Therefore, the main purpose of this feeding investigation was to evaluate the effects of methionine-derived MMSC supplementation on performance, feed efficiency, blood constituents, body chemical composition and intestinal morphometric characteristics of Nile tilapia, as well as to investigate the key molecular mechanisms of the observed alterations.…”