Modulatory effects of in ovo delivery of galactooligosaccharide and Lactiplantibacillus plantarum on antioxidant capacity, gene expression, and selected plasma metabolite parameters of broiler chickens

A stable gut microbiota promotes a healthy gut and enhances immune function, antioxidant status, and metabolic activities in chickens. The present research work aimed to investigate the modulatory impacts of in ovo delivery of prebiotic and probiotic on oxidative stress, the intestinal transcriptome, and various plasma metabolites in chickens. Fertilized Ross 308 eggs were administered in ovo either with galactooligosaccharide (GOS) (3.5 mg/egg or Lactiplantibacillus plantarum (LP) 1 × 10⁶/egg on the 12th day of egg incubation. Three hundred viable Ross 308 broiler hatching eggs in total were randomly assigned to four groups, namely, the negative control not injected group, the group receiving physiological saline injections as the positive control, GOS, and LP. The analysis of genes associated with immune functions, antioxidants, barrier functions, and free fatty acid receptors were determined via qPCR. The analysis of the selected plasma blood metabolites was performed automatically with Pentra C 400. The antioxidant capacity of the chickens' liver, breast muscle, and spleen was enhanced by the in ovo injection of GOS and LP. The immune-related gene expression levels were upregulated after in ovo stimulation with either GOS or LP which improved the gut health of broiler chickens. In addition, several genes related to gut barrier functions were upregulated, thus ensuring epithelial integrity. As for blood plasma metabolites, no adverse effects were observed. In summary, we report that in ovo stimulation with either GOS or LP stimulates the immune system and improves the antioxidant status and gut health of chickens with no negative impact on plasma blood metabolite indices.