Vaccination is an important mainstay of biosecurity and disease prevention in livestock farming. Vaccination failures represent an economic burden for the farmer. Polyphenol supplementation, known for its antioxidant properties, could help reduce oxidative damage and improve the success of vaccination. We evaluated the effect of a rumen-protected grape extract (RPGE) supplementation around vaccination on the immune response in young ruminants.

Heat stress (HS) in dairy cows disrupts homeostasis and thermoregulation, negatively affecting milk production, health status, and metabolism. Dietary supplementation with phytoextracts such as polyphenols may offer an effective dietary strategy by stimulating the immune system, reducing oxidative stress, and ultimately enhancing welfare, metabolic function, and milk performance. This study aimed to evaluate the effects of supplementing mid-lactating Fleckvieh cows with rumen-protected grape extract (Nor-Grape BP-O, Nor-Feed) on milk performance, rectal temperature (RT), behavior, immunometabolism, rumen fermentation, and innate immune response under naturally occurring HS conditions (temperature-humidity index >72). Thirty cows were balanced by days in milk, milk yield, and parity, and randomly assigned to receive either 470 mg/cow per day of Nor-Grape BP-O supplementation (NG-BPO, n = 15) or a control diet without supplementation (CTR, n = 15) and monitored for 35 d. Both groups were cooled daily using forced ventilation and fans. Temperature-humidity index, milk yield, heavy breathing (HB), rumination, and eating time were recorded daily. Milk, blood, and rumen fluid samples were collected at different time points, and RT was measured. The NG-BPO cows exhibited greater milk production, fat-corrected milk, energy-corrected milk, and yields of fat and protein, alongside lower SCC compared with CTR cows. The NG-BPO cows exhibited improved thermoregulatory responses, reflected by significantly lower RT and reduced HB. Supplementation with Nor-Grape BP-O lowered inflammatory status and enhanced innate immune responses, as indicated by higher plasma zinc and myeloperoxidase levels, lower haptoglobin concentrations, and increased phagocytic activity of neutrophils and monocytes compared with CTR cows. These findings were supported by higher levels of proinflammatory cytokines TNF-α and IL-1 β during peak HS periods, compared with CTR cows. In addition, the NG-BPO group had lower circulating platelet and eosinophil counts compared with the CTR group. In conclusion, supplementation with a low dose of rumen-protected dry grape extract-rich in low-molecular-weight polyphenols (oligomeric and monomeric flavanols, anthocyanins)-effectively supported milk production and quality in heat-stressed dairy cows. Moreover, supplementation improved thermotolerance during heat waves and enhanced innate immune functions while reducing inflammatory responses. These findings suggest Nor-Grape BP-O as an effective dietary strategy to mitigate the negative effects of heat stress by enhancing cow performance and welfare during periods of elevated environmental temperatures.

In laying hens, maintaining optimal bone health and development from the early stages is crucial, as it directly affects their egg-laying efficiency, overall welfare and productivity. Studies have shown that grape polyphenols from Vitis vinifera enhance bone health in both humans and animals. Still, the mechanisms behind this effect remain unclear, given the diversity of grape polyphenols and their varying mechanisms of action. The objective of this study was to investigate the effect of a standardized dry grape extract (SDGE) on bone quality and metabolome of future laying hens reared in commercial conditions. Therefore, 36300 day-old pullets were randomly divided into two barns on the same farm site. Both received the same diet, with the addition of 30 mg/kg of SDGE (Nor-Grape®, Nor-Feed, France) from day 1 until week 17 in the supplemented group (SDGE). At the end of the supplementation period, several bone quality parameters were analyzed on 50 individuals per group. Additionally, non-targeted metabolomics on plasma and bones were performed to uncover the impact of SDGE supplementation on pullet's metabolome. Results demonstrated that keel bone deformity tended to improve following SDGE supplementation (P = 0.10). Moreover, SDGE intake significantly increased bone dry and mineral content, compared to the control group (P < 0.05) and tended to increase calcium (Ca) (P = 0.074) and phosphorus (P) content (P = 0.055). On the other hand, non-targeted metabolomics on plasma samples revealed an impact on fatty acids and glycerophospholipid metabolisms while bone samples analysis uncovered pathways related to sphingolipid and estrogen mediated signaling pathways. Overall, this study suggests novel mechanisms related to estrogen signaling through lipid metabolism in SDGE supplemented pullets and highlights that nutritional intervention with SDGE in early developmental stage of future laying hens improves their bone health prior to entry into the laying phase, thus proving a useful tool in bone health management.

Oxidative stress can impair poultry health and performance, underscoring the importance of enhancing endogenous antioxidant defenses as a nutritional strategy. Although plant-derived polyphenols have shown antioxidant potential, their efficacy remains inconsistent owing to variability in extract composition and the frequent evaluation of doses exceeding those authorized for commercial use. This study investigated the effects of dietary supplementation with a standardized dry grape extract (SDGE, Nor-Grape^®, Nor-Feed, France) at an authorized inclusion level (30 mg/kg feed) on growth performance and antioxidant status in broiler chickens under commercial production conditions. A total of 756 one-day-old male Ross 308 broilers were randomly allocated to a control diet (CTL, n = 392) or the same diet supplemented with grape extract (NG, n = 364) for 35 days. Growth performance was recorded throughout this study, and blood samples collected on days 11 and 35 were analyzed for total antioxidant capacity (TEAC), lipid peroxidation (TBARS), and the activities of the endogenous antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Compared with controls, NG birds exhibited greater final body weight (+71.9 g; p < 0.001) and improved FCR during the finisher phase (p < 0.05). Supplementation significantly enhanced systemic antioxidant capacity and endogenous antioxidant enzyme activities while reducing lipid peroxidation, indicating improved oxidative status. These findings demonstrate that SDGE supplementation at commercially authorized inclusion levels effectively enhances antioxidant defenses and improves production performance in broiler chickens.