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The free-range system improves chicken's welfare and enriches their diet. There is little information about influence of chickens on the sward quality. The aim of the study was to identify differences in the chemical and botanical composition of the pasture sward used by chickens and to assess if frequency of chicken exits outdoors is associated with the botanical composition of the ranging areas. One hundred twenty non-beak trimmed mixed sex birds of Green-legged Partridge (GP) and Sasso line C44 (S) were used. Each pen had direct access to an individual outdoor range providing 10.5 m2 per chicken, video-recorded continuously. Vegetation coverage regarding botanical composition was determined based on botanical-weight analysis from three control plots, while range use was calculated from the video material. The data were analysed by ANOVA model in SAS software (v 9.4). Regarding chemical composition, fiber content was higher in dry matter from the control pastures. Significantly more Dactylis glomerata (L.) and Alopecurus pratensis (L.) were observed on ranges used by Sasso. The higher share (%) of weeds and grasses was at the ranges used by chickens (weeds: S:8.66 (1.42) and GP:7.61 (0.59) and grasses: S:10.36 (0.96) and GP:12.10 (0.65)) as compared to control plots (1.45 (1.34)) and 3.86 (2.97), respectively) in contrast to legumes ((S:0.01 (0.01) and GP:0.32(0.26)) and sedges (S:0.64 (0.48) and GP: 0.09 (0.06)) most present in the control plots (10.88 (1.55)). Positive association between range use frequency and proportion of Heracleum sphondylium (L.), Rumex acetosa (L.), Festuca rubra (L.), and Lolium perenne (L.) was observed for Sasso, while foe Green-legged Partridges with proportion of Armoracia rusticana (L.), Stellaria media (L.), Ranunculus repens (L.), Cirsium arvense (L.) and Rumex crispus (L.). Concluding, the sward quality of the ranging areas was affected by the presence of the chickens and it differed between genotypes. Unknown remain if birds used the pasture more frequently depending on its botanical composition or if the pasture composition depended on the frequency of its uses by the birds. [ABSTRACT FROM AUTHOR]

Despite the existing research into the gut microbiome of meat chickens, the associations between gut microbiome composition, its activity and chicken outdoor ranging frequency remain unexplored. The aim of this study was to determine the gut microbiota composition, activity and metabolic products in chickens of 2 different lines and 3 ranging profiles. Sixty non-beak trimmed birds, either Sasso or Green-legged Partridge were housed with access to outdoor ranges from wk. 5 to 10 of age. Outdoor ranges were video recorded to obtain frequencies of the birds' range use. The information about relative abundance of selected bacterial groups in the ceca including Lactobacillus spp., E. coli, Bifidobacterium spp., and Clostridium spp. was obtained with the PCR method. Gut microbiota activity was assessed based on the glycolytic activity of bacterial enzymes including, α-glucosidase, β-glucosidase, α-galactosidase, β-galactosidase, and β-glucuronidase as well as based on the concentration of short-chain fatty acids (SCFA) in the caecal digesta. Statistical analysis was conducted by generalized linear mixed models, applying the breed and ranging profile as fixed effects and pen as a random factor. The lowest relative abundance of Bifidobacterium spp. was found in the cecal content of indoor-preferring Sasso birds (0.01 ± 0.001), as compared to all other birds in the experiment (ranging from 0.03 ± 0.01 to 0.11 ± 0.07; P = 0.0002). The lowest relative abundance of E. coli was identified for all outdoor-preferring birds and indoor- preferring Sasso birds (0.01 ± 0.001; P = 0.0087). Cecal activity of: α-glucosidase, β-glucuronidase and β-galactosidase was higher in Green-legged Partridges, as compared to Sasso (P = 0.013; P = 0.008; P = 0.004). Valeric acid concentrations were higher in moderate Green-legged Partridges than in Sasso of the same ranging profile (2.03 ± 0.16 vs. 1.5 ± 0.17; 0.016). The majority of the current results confirmed an effect of genotype and ranging profile on the various analyzed parameters. In outdoor-preferring birds, the consumption of pasture originating feed sources as a supplement to the indoor accessible cereal-based diet likely caused the positive effects on the birds' microbial profile. [ABSTRACT FROM AUTHOR]