Effects of alternative bedding materials on metabolism, performance, hygiene, immune-related genes expression and meat quality of broilers under conventional and organic production systems

: This study evaluated two alternative bedding materials (poplar pellet-PP and vine pellets-VP) in against conventional wood shavings (WS) on production performance, health status, hygiene, immune-related genes expression and meat quality of broilers reared in organic-like conditions. A total of 252 male Ross-308 chicks were assigned to 9 pens in a randomized blocked design with 3 replicates; 50 % were slaughtered at 42d while the remaining at 84d in accordance with organic farming regulations. Broilers raised on VP resulted in lower body and carcass weight than those on PP, which had the lowest feed conversion ratio at 63d. Compared to WS broilers on PP were heavier, cleaner and had lower water consumption, water consumption ratio, and water to feed ratio in organic rearing period. Pelleted beddings were drier until mid-trial; PP had a consistently higher fiber content (aNDF, ADF, lignin) than WS. Despite higher microbiological contamination pelleted beddings did not affect Lactobacillus spp. growth. Poplar pellet increased footpad and hock score (HS), while VP improved HS and plumage cleanliness (CS) at 28d but worsened HS at 84d. A blood protein reduction was observed in pellet beddings leading to increased creatinine levels. Birds reared on PP had the greatest thickness of tunica mucosa, villus-height (VH) and VH /crypt depth ratio at 42d. At 84d, VP increased IL-8 expression and reduced survival rate compared to PP. Overall, from a production perspective, pelleted beddings are suitable for fast-growing broiler hybrids under conventional and organic regimens. The PP is particularly recommended for organic production systems.