Effects of Undernutrition and Hydroxytyrosol Supplementation in Late Pregnancy on Growth and Metabolic and Endocrine Profiles of Male Beef Offspring During the Fattening Phase

Maternal undernutrition in late gestation can compromise fetal development and postnatal productivity in beef cattle. This study evaluated whether maternal supplementation with hydroxytyrosol (HT)—a potent antioxidant from olive by-products—during late gestation could alleviate the effects of undernutrition on growth, concentrate conversion ratio, and metabolic and endocrine adaptation of male offspring during the fattening phase. Forty-six multiparous pregnant cows were assigned to four dietary treatments combining nutritional level (T100% vs. T60% of nutritional requirements) and HT supplementation (CONTROL vs. HT at 180 mg/kg of diet) exclusively during the last third of pregnancy. Maternal undernutrition reduced calf morphometric development at the beginning of fattening (4 months), although compensatory growth enabled recovery by slaughter (12 months). For live weight (LW), the feeding level and HT interaction showed a tendency (p = 0.084), but pairwise comparisons within the restricted groups suggested that calves from HT-supplemented dams were 31 kg heavier at slaughter than calves from non-supplemented dams (p = 0.023). HT supplementation was also associated with higher plasma urea concentrations at 12 months in restricted calves, suggesting potential adaptations in nitrogen metabolism without changes in glucose or IGF-1 profiles. In summary, these findings might support our hypothesis suggesting potential benefits in the development of male offspring from HT-supplemented cows during the last third of gestation. However, further studies will be needed to demonstrate definitive overall evidence of HT benefits.