Effects of maternal vitamin A injection during late gestation on maternal physiology, offspring performance, and recruitment of cells for myogenesis and adipogenesis in offspring muscle tissue

Abstract

The objective of this study was to evaluate the effects of maternal vitamin A injection during late gestation on placental adaptations, lactation performance, and offspring skeletal muscle development in Tabapuã beef cattle. The experiment was conducted over two years using 41 pregnant Bos indicus (Tabapuã) cows. At 245 days of gestation, cows were blocked by parity and assigned to one of two treatments: control without vitamin A injection (CON, n = 21) or vitamin A injection (VA, n = 20). Cows in the VA group received intramuscular injections of vitamin A (2,700,000 IU) at 245, 260, and 275 days of gestation. Data were analyzed using the MIXED procedure of SAS in a randomized complete block design with a 2 × 2 factorial arrangement (treatment × offspring sex). Maternal vitamin A injection tended to reduce gestation length in cows carrying female fetuses (P = 0.07) and decreased maternal body weight at 275 days of gestation (P = 0.09). Additionally, VA-treated cows carrying male fetuses exhibited greater plasma retinol concentrations at 275 days of gestation (P < 0.10). Male fetuses exhibited greater gestational gain (0.702 vs. 0.610 kg/day) and placental weight compared with females. VA-treated cows carrying female fetuses exhibited approximately 11.5% greater vascular area density and 20% greater capillary area than CON cows carrying female fetuses, along with greater STRA6 expression (P = 0.04). A significant VA × Sex interaction was observed for birth weight (P = 0.05), in which female calves born from vitamin A-treated cows had lower birth weight. During lactation, vitamin A injection increased milk yield and milk fat and protein concentrations, with the greatest milk production observed in cows nursing male calves (P = 0.02). At weaning, male calves exhibited greater body weight (P = 0.01) and average daily gain (P = 0.05) compared with females. Calves born from VA-treated cows exhibited greater muscling index (P = 0.01) and tended to present greater longissimus muscle length (P = 0.06). In offspring skeletal muscle, maternal vitamin A injection upregulated genes associated with adipogenesis (ZNF423 and PPARG) and myogenesis at birth (PAX7), characterized by increased adipogenic and myogenic indices and lower myostatin abundance. Male offspring exhibited greater activation of retinoic acid signaling (ALDH1A2) and myogenic pathways (MYOG). At weaning, offspring from vitamin A-treated cows maintained a greater adipogenesis:myogenesis balance (P = 0.07) and increased Nfix expression (P = 0.10), a transcription factor associated with muscle fiber formation. In summary, maternal vitamin A injection during late gestation modulated placental vascularization, improved milk production and composition, and stimulated adipogenic and myogenic programming of offspring skeletal muscle in a sex-dependent manner, indicating that prenatal vitamin A administration may enhance developmental and carcass-related traits in beef cattle.