Dietary lipid requirements of the teleost pejerrey (Odontesthes bonariensis): gene expression of muscle growth biomarkers and the GH/IGF system

CANOSA LF; GOMEZ-REQUENI P; KRAEMER MN

Fishes

MDPI AG

Lugar: Basel; Año: 2019 vol. 4 p. 37 - 50

Abstract: Gene expression of growthhormone receptors (GHRs), insulin-like growth factors (IGFs), myostatin (MSTN)and myogenin (MyoG) was analyzed in juveniles pejerrey fed with graded levelsof lipids (L): 6% (L6), 10% (L10), 25% (L25). After 14 weeks, no changes werefound in liver GHR-I GHR-II and IGF-II mRNA levels whereas IGF-I decreased inL10 and L25. Muscle GHR-I gene expression increased in L25 whereas GHR-II,IGF-II and MyoG were higher in L6. IGF-I and MSTN expression was not affected bythe different diets. Adipose IGF-I mRNA levels decreased in L10. Correlationsbetween body weight and members of GH/IGF system in liver and skeletal muscle werefound only in L10 group. Correlations found in L10 group between both liver andskeletal muscle GHR-I and IGF-I were lost in either L6 or L25 groups. Thus,fish fed with apparently unbalanced dietary lipid contents (6% and 25%) exhibita compensatory regulation of systemic and local components of the GH/IGF axis.Furthermore, the marked inhibition of muscle MyoG gene expression in L25 mightlimit excessive lipid deposition and fish growth. Our data suggest that adietary lipid contents of 10% would promote a particular adjustment of theendocrine and autocrine/paracrine GH/IGF system, stimulating body growth andperhaps muscle hyperplasia. On the other hand, a higher dietary lipid contentwould uncouple the GH/IGF system, reducing hepatic IGF-I while slightlyincrease hepatic GHR-I, probably to prompt lipolysis.