Location: Cool and Cold Water Aquaculture ResearchTitle: Dietary methionine restriction: Effects on glucose tolerance, lipid content and micro-RNA composition in the muscle of rainbow trout
|LATIMER, MARY - University Of Alabama|
|BIGA, PEGGY - University Of Alabama|
Submitted to: Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2017
Publication Date: 5/4/2018
Citation: Latimer, M., Cleveland, B.M., Biga, P. 2018. Dietary Methionine Restriction: Effects on glucose tolerance, lipid content and micro-RNA composition in the muscle of rainbow trout. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 208:47-52. https://doi.org/10.1016/j.cbpc.2017.10.012.
Interpretive Summary: Methionine is an essential amino acid critical for optimal growth performance in all animals, including rainbow trout. However, aquafeeds contain protein sources that are relatively low in methionine so feeds are often supplemented with free-methionine to meet the requirement of the fish. Understanding the mechanisms through which methionine regulates growth and muscle development is central for optimizing fish nutrition. Mechanisms involving micro-RNAs, small RNA molecules that regulate gene expression, are of particular interest as they are relatively novel and not completely characterized. This study investigates growth, glucose tolerance, and the micro-RNA response in rainbow trout consuming a methionine-restricted diet. Although growth performance was not affected, methionine-restricted fish demonstrated altered fat deposition and reduced expression of micro-RNAs that regulate muscle growth dynamics. These results suggest that sustained consumption of methionine-restricted diets negatively affect nutrient deposition and muscle development, partially through micro-RNA-related mechanisms.
Technical Abstract: Lean muscle mass plays an important role in overall health, as altered skeletal muscle metabolism can impact both the incidence and prevention of conditions related to metabolic health. Intriguingly, dietary methionine restriction (MR) has been shown to ameliorate this phenotype over time potentially through mechanisms related to changes in myogenic precursor cell (MPC) differentiation status. Recently the role of micro-RNAs (miRs) in regulating the expression of muscle specific transcription factors myoD and myogenin as well as signaling molecules involved in skeletal muscle differentiation has been reported in vitro. We performed an 8 week feeding trial to determine if MR in vivo could alter miR abundance as well as change in metabolic markers. Results show changes in muscle miR abundance for miR-133a at 4 weeks with no significant difference seen in miR-210 or miR-206. After 8 weeks of MR feeding fish demonstrated increased clearance of a glucose load, increased fat accumulation in the liver, and decreased fat accumulation in the muscle.