Synbiotics as Modulators of Developing Brain for Reproductive Development Via Estrogen Receptors in Male Coturnix Coturnix Japonica

The brain-gut–microbiome axis represents a bidirectional communication linking the gastrointestinal microbiome with immunity, digestion, reproduction and nervous system. Dietary supplementation of Lactobacillus rhamnosus, Bifidobacterium longum and mannan-oligosaccharides may modulate the brain-gut-axis and also have an effect on male reproductive physiology. Therefore, the study aims to explore the reproductive and neuronal physiology potentials of synbiotics in immature male Japanese quails. To achieve this, two weeks old quails were supplemented with 1% Lactobacillus rhamnosus (L), Bifidobacterium longum (B) and mannan-oligosaccharides (M) in their diet, individually as well as in combinations (LB and LBM) for 28days. The oxidative stress markers including malondialdehyde (MDA), hydrogen peroxide (H₂O₂), advanced oxygen protein products (AOPPs); antioxidant enzymes {Superoxide Dismutase (SOD), Catalase} and coenzyme Glutathione (GSH); monoamine oxidase (MAO) and acetylcholinesterase (AchE) activity were estimated in the brain. Inflammatory biomarkers (IL-10, IL-1β and NF-κB), apoptotic biomarkers (caspase-3 and caspase-7) and for reproductive aspect viz. gonadotropin releasing hormone (GnRH) and estrogen receptors (ER-α and ER-β) were analyzed by immunofluorescence in the brain. The results revealed that dietary supplementation with 1% LBM or synbiotics significantly enhances the number of neurons in the hippocampal area, antioxidant enzymes (SOD and Catalase) while it reduces MDA, H₂O₂ and AOPP. Synbiotics increases IL-10 expression and a substantial reduction in IL-1β and NF-κB which limits inflammation as well as apoptosis (Caspase-3 & Caspase-7) with increased AchE, MAO activity in the developing brain. Our findings indicate that synbiotics interfere and enhance neuronal development processes and are associated with fertility manifested by upregulated expression of GnRH, ER-α, ER-β in brain. Overall, combined use of pro, pre, synbiotics have a synergistic effect and serve as modulators in neuro-immune processes and fertility in developing brain of quail.