Effects of supplementing pregnant ewes with prenatal calcium salts of soybean on the growth characteristics, nutritional parameters, and meat quality of their offspring

Nutritional signals during gestation shape fetal growth, metabolic programming, and tissue development. However, how specific maternal diets drive these outcomes in small ruminants remains unclear. Therefore, this study evaluated how maternal feeding regimen (FR) during gestation of ewes affects their offspring growth, nutrient utilization, and meat quality, including potential interactions with offspring sex (OS). At 74 days of gestation, 30 multiparous ewes [44.1 ± 6.90 kg body weight (BW)] were randomly assigned to: (1) Control (CON; n = 16; 9 male and 7 female fetuses) – basal diet meeting requirements for singleton pregnancies, or (2) CSSO (n = 14; 7 male and 7 female fetuses) – basal diet plus calcium salts of soybean oil (1.5 g/kg BW). Lambs remained with their dams until weaning, were finished in a feedlot, and slaughtered at 32–33 kg BW. At 15 days of age, muscle biopsies were collected for gene expression analyses. A digestibility trial was conducted during the finishing period, and carcass traits were recorded at slaughter. At slaughter, longissimus lumborum and subcutaneous adipose tissue samples were collected for histological evaluation, while latissimus dorsi muscle and adipose tissue samples were used for gene expression analyses. Significance was declared at P < 0.05. Lambs from CSSO-supplemented ewes had 15 % greater birth BW than CON (P = 0.01). At 15 days, Zinc finger protein 423 (ZFP423) expression was greater in CSSO-females (FR × OS: P < 0.01), and Myogenin (MYOG) was upregulated in CSSO vs. CON lambs (P = 0.05). At slaughter, Mechanistic target of rapamycin (MTOR) expression in skeletal muscle was greater in CON-males, while Peroxisome proliferator-activated receptor gamma (PPARG) expression was upregulated in CSSO-females relative to other groups (P < 0.01). The Myosin heavy chain type I (MyHC-I) expression was reduced in the skeletal muscle of CSSO offspring at slaughter (P = 0.02). In subcutaneous adipose tissue, PPARG expression was greater in CSSO lambs than in CON (P = 0.01). Muscle fiber area, perimeter, and diameter were greater in CSSO-females (FR × OS: P < 0.05), and adipocyte density was greater in CSSO than CON offspring (P = 0.02). No effects of maternal diet or FR × OS interaction were detected for carcass traits (P ≥ 0.09) or on biochemical and structural meat quality parameters, including water-holding capacity, muscle pH, instrumental tenderness, and color attributes (P ≥ 0.11). Therefore, maternal CSSO supplementation modulates early postnatal muscle and adipose tissue development. However, these changes do not lead to significant long-term effects on growth performance, carcass traits, or meat quality.