Bee propolis extract as a phytogenic feed additive to enhance diet digestibility, rumen microbial biosynthesis, mitigating methane formation and health status of late pregnant ewes

Late pregnancy is one of the most critical stressed periods of reproductive lives of ewes that can effectively affect the whole animal subsequent productive life. Propolis is considered as an effective enhancer of rumen fermentation and the whole animal health conditions in growing and dairy cattle; however no study has confirmed these positive effects in late pregnant ewes. The aim of this study was to evaluate the beneficial effects of supplementing red propolis extract (RPE) on apparent digestibility, purine derivatives, methane (CH₄) emission and blood metabolites of late pregnant ewes. Eighteen Santa Inês ewes (52.5 ± 2.50 kg body weight) were kept individually in indoor pens. The trail lasted for 44 d of which 14 d were for adaptation and 30 d for data collection. Ewes were allotted into a randomized complete block design (9 blocks × 2 dietary treatments). The treatments were: control diet (CTL); the basal diet without supplementations and propolis diet (RPE); the basal diet supplemented with 3 g RPE/ ewe/ day. The GC/MS analysis of RPE showed 20 different components all belonging to the flavonoids class were detected. Propolis supplementation increased (P = 0.02) organic matter and crud protein digestibility compared to the control. Higher intake of nitrogen (P = 0.03) and body N retention (P = 0.01) were observed with RPE supplementation compared to CTL, also, the retained N expressed as g/g N intake tended to increase (P = 0.063). The administration of RPE increased (P < 0.05) urinary allantoin derivative excretion and also total purine derivatives (PD) tended to increase (P = 0.06) for RPE compared to CTL. Enhanced individual, total short chain fatty acids and acetate/propionate ratio were exhibited (P < 0.05) by RPE supplementation compared to CTL. Additionally, RPE decreased (P < 0.05) CH₄ emission compared to CTL. All hematological parameters and biochemical parameters including total protein, globulin and glucose were enhanced (P < 0.05) by RPE supplementation compared to CTL. Propolis supplementation decreased (P < 0.05) the tested hormones cortisol, triiodothyronine and thyroxine compared to CTL. This study illustrated that RPE represent a promising diet natural supplement for supporting body activates during the transition from late pregnancy to lactation without adverse impact on either animal productivity or environment.