In a market undergoing constant evolution, the production of chicken meat that consumers would perceive as “natural” and “animal friendly” is crucial. The use of probiotics in rurally reared chickens could represent a major opportunity to achieve mutual benefit for both the industry and consumers. A total of 264 male Kabir chicks were randomly distributed to one of 2 dietary treatments: the L group received a commercial feed supplemented with 2.0 g/100 kg of Lactobacillus acidophilus D2/CSL, while the C group received the same basal diet without the additive. To assess the effects of probiotic supplementation in the chickens’ diet, productive performance was evaluated at d 21 and 42, whereas microbiological analyses of the intestinal content and intestinal histology and morphometry were performed at the end of the trial (d 42). At d 21 and 42, L birds showed better (P < 0.001) performance in terms of body weight, average daily gain, and feed conversion ratio. Enterococci, staphylococci, and Escherichia coli populations were not influenced by dietary treatment. On the contrary, Lactobacillus population increased (P = 0.032) in the L group. Furthermore, a tendency (P = 0.069) was observed for the coliforms to be influenced by diet, with lower values in the L group in comparison to the C group. Histological techniques revealed that the number of goblet cell containing neutral mucins was lower in the C group. Morphometric evaluations demonstrated that the probiotic supplementation increased the height of the mucosal layer by improving (P = 0.040) villus height, while crypt depth was unaffected. In conclusion, the results obtained in this study demonstrate that it is possible to use Lactobacillus acidophilus D2/CSL (CECT 4529) in rurally reared chicken breeds with positive effects on performance and gut health.

The aim of the present study was to investigate the effect of transport on welfare traits, several haematological parameters and carcase hygiene in two different chicken genotypes (fast-and slow-growing strains) reared under free-range conditions. For this aim, two hundred male chicks, 100 from fast-growing (Ross 308, R) and 100 from slow-growing (Naked Neck, NN) strain were farmed. At the end of the rearing period, at 81 days of age, 56 birds/strain were randomly selected for slaughtering and submitted to two different pre-slaughter conditions: no transport (0h) or 4 hours of transport (4h). Tonic immobility (TI), blood parameters and carcase hygiene traits were determined. Strain and transport significantly affected TI of birds. Both experimental factors and their interaction significantly affected plasma creatine kinase, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase. Cholesterol and triglycerides were not different between the experimental groups, whereas glucose decreased after 4 hours of transport in both strains. A significant difference between groups for the heterophils/lymphocytes ratio after transport was also observed, with NN being higher than Ross. Concerning the oxidative stress, we observed a higher ROS production in NN chickens. The carcase microbial characteristics showed a higher level of contamination after the transport (total viable counts), but not concerning the Enterobacteriaceae counts.