Effect of rearing system (free-range vs cage) on gut and muscle histomorphology and microbial loads of Italian White breed rabbits

Abstract

Objective: The growing consumers’ interest on animal welfare has raised the request of products obtained by alternative rearing systems. The present study was conducted to assess the influence of housing system on gut and muscle morphology and on microbial load in rabbits reared under free-range (FR) and cage system (CS).Methods: A total of forty weaned (35 days of age) male Italian White breed rabbits were allotted according to the rearing system, and at 91 days of age were randomly selected and slaughtered for the morphological evaluation of tissue from duodenum and <i>longissimus lumborum</i>. Morphometric analysis of the villus height, villus width, crypt depth, villus height/crypt depth ratio, and villus surface was performed. The microbial loads on hind muscle was determined by total mesophilic aerobic count (TMAC), <i>Escherichia coli</i> and <i>Enterobacteriaceae</i>; whereas, total anaerobic bacteria count (TABC) and TMAC, <i>E. coli</i> and <i>Enterobacteriaceae</i> was determined on caecal content.Results: Rearing system did not interfere with the duodenum and muscle histomorphology in both rabbit groups. Similarly, microbial load of caecal content showed no significant differences on the TABC and TMAC. Conversely, significant difference was found for <i>E. coli</i> strains in caecal content, with the lower counts in FR compared to CS rabbits (p<0.01). Microbiological assay of muscle revealed significant lower TMAC in FR vs CS rabbits (p< 0.05). All rabbit meat samples were negative for <i>E. Coli</i> and <i>Enterobacteriaceae</i>.Conclusion: Free-range could be considered a possible alternative and sustainable rearing system in rabbits to preserve gut environment and muscle quality.