Influence of Chromium Propionate Supplementation in Ewes During the Gestational Phase on the Regulation of Genes Associated with Growth and Metabolism in the Offspring

Abstract Maternal chromium (Cr) supplementation has been associated with altered offspring growth, carcass traits, and tissue gene expression in several species, but underlying programming mechanisms in sheep remain unclear. This study evaluated the effects of late-gestation and early-lactation dietary chromium propionate in ewes on the expression of genes related to myogenesis and lipid metabolism in the progeny. Sixty-nine Dorper × Santa Inês ewes were assigned, in a randomized block design, to receive 0 (CR0), 0.5 (CR0.5), or 1.5 mg/day (CR1.5) of chromium propionate per ewe from the last 50 days of gestation through the 80 days of lactation. Lambs received no supplemental Cr. After weaning, 18 single-born male lambs (approximately 80 days of age; 31.64 ± 6.07 kg) were finished in a feedlot for 52 days and slaughtered at 47.39 ± 7.15 kg. Samples of longissimus muscle, liver, and subcutaneous adipose tissue were collected for RT-qPCR analysis of MYOD, FASN, LPL, LIPE, IGF1, and IGFBP2. Maternal Cr supplementation altered ( P < 0.05) offspring gene expression in a tissue- and dose-dependent manner. The CR1.5 treatment downregulated MYOD, FASN, LIPE, and IGF1 in skeletal muscle and liver, while upregulating LPL in muscle and IGFBP2 in liver ( P < 0.05). In adipose tissue, LPL was upregulated by CR1.5, and LIPE by CR0.5 ( P < 0.05). These changes are consistent with enhanced lipolysis in adipose tissue and a redirection of energy toward muscle deposition. In conclusion, chromium propionate administered to ewes during late gestation and lactation promotes fetal programming by modulating the expression of myogenic and lipid-metabolism genes in the liver, skeletal muscle, and adipose tissue of the offspring.