Effect of housing systems on inflammatory and regulatory gene expression in blood and spleen of Popielno White rabbits

Abstract The development of welfare-oriented rabbit production systems requires a better understanding of how housing conditions affect physiological and immune responses at the molecular level. This study evaluated the effect of housing systems on the expression of selected genes related to inflammation, immune regulation, and adaptation in Popielno White (PW) rabbits. After weaning at 35 days of age, female rabbits were allocated to five housing systems differing in design and environmental exposure: hutches with an outdoor run, rabbit tractor cages with an outdoor run, conventional cages without bedding, deep-litter pens, and modified cages connected by a plastic pipe ( n = 16 per group). At 2,600–2,900 g body weight (90–120 days of age), blood and spleen samples were collected. The relative expression of IL6, CXCR1, IL10, TGFB1, IL8, PTGS2, IL1B, and TNF was determined by reverse transcription quantitative polymerase chain reaction using β-actin and beta-2-microglobulin as reference genes. Housing system affected the expression of several immune-related genes, with more pronounced responses observed in blood than in the spleen. Outdoor systems (A and B), modified cages (E), and deep-litter pens (D) were associated with distinct patterns of inflammatory and regulatory gene expression. Following FDR correction, significant housing-related effects were confirmed for a subset of genes, indicating tissue-dependent modulation of immune-related pathways. Overall, the results suggest that housing conditions influence molecular indicators of immune responsiveness in PW rabbits. Gene expression profiling may complement conventional physiological and welfare-related assessments in studies evaluating rabbit housing systems.