Molecular changes in the intestinal barrier function of broiler chickens with bacterial chondro-necrosis and osteomyelitis

The aim of the study was to evaluate the characteristics of gene expression of inflammation, apoptosis, and intestinal barrier function markers in broiler chickens with bacterial chondronecrosis and osteomyelitis, as well as under the influence of a composition of organic (fatty) acids. The study was conducted on ROSS-308 broiler chickens under commercial production conditions. Experimental groups were formed retrospectively according to clinical status. Samples of the small and large intestine, chyme, and feces were collected for molecular analysis. The relative expression levels of the genes TNF-α, IL-1β, Caspase-9, Claudin-1, Occludin, MUC-2, and Fibronectin were determined using the RT-qPCR method. It was established that under pathological conditions, a redistribution of the inflammatory response occurs between the tissue and luminal compartments of the intestine, manifested by decreased TNF-α expression in the small intestine and increased IL-1β expression in chyme and feces. Changes in Caspase-9 expression indicate modification of apoptotic processes, with a tendency toward suppression in tissues and possible enhancement in the luminal environment. Impairment of the intestinal barrier function was revealed, as confirmed by decreased expression of Claudin-1 and MUC-2 in tissues and feces, as well as multidirectional changes in Occludin expression. Increased Fibronectin expression in the luminal compartment indicates activation of extracellular matrix remodeling processes and destructive-reparative changes in the mucous membrane. The obtained results indicate a profound restructuring of the functional state of the intestine in bacterial chondronecrosis and osteomyelitis, accompanied by an imbalance between inflammation, apoptosis, and barrier function. The use of a composition of organic acids may modify the nature of the intestinal response, contributing to the limitation of inflammation in tissues and the maintenance of intestinal barrier integrity.