Probiotic fermented feed improved the production, health and nutrient utilisation of yellow-feathered broilers reared in high altitude in Tibet

1. Probiotic fermented feed (PFF) has been widely used in poultry production. The current study was designed to investigate whether PPF could alleviate the negative effects of hypoxia on yellow-feathered broilers reared at high altitude on the Tibet Plateau. 2. A total of 480, one-day-old male Lingnan yellow-feathered broilers were divided into four treatment groups with six replicates, each containing 20 broiler chickens. Broilers in the four groups were offered either a basal diet (without antibiotics) or test diets containing 5, 10 and 15% of PFF respectively. The experiment lasted for eight weeks. 3. Birds fed the 10% PFF diet exhibited increased (P < 0.05) average daily gain (ADG) on d 28 and 56, body weight (BW) on d 56, total tract apparent digestibility (TTAD) of dry matter (DM), crude protein (CP) and gross energy (GE). Feeding diets supplemented with 10% PFF increased (P < 0.05) digestive activity and gut development in duodenum and jejunum. Supplementation with 10% or 15% PFF significantly increased (P < 0.05) the caecal populations ofLactobacilliandBifidobacteria spp. and decreased (P < 0.05) caecalE. coliandSalmonella spp. on d 28 and 56. 4. The ADG and BW on d 56, protease activity in duodenum on d 56 and jejunum on d 28 and 56, villus height and villi absorptive area in duodenum and jejunum and caecalBifidobacteria spp. showed a quadratic (P < 0.05) dose response as supplemental PFF level increased. The TTAD of DM and CP and caecalLactobacilli spp. increased linearly with PFF level. The caecal populations ofE. coliandSalmonella spp. decreased linearly with PFF level. 5. In conclusion, addition of PFF in broiler diets had the potential to improve production performance, nutrient utilisation, intestinal digestive function and caecal microflora in yellow broiler chickens raised at high altitude.