Early life fecal microbiota transplantation enhances fermentation potential by changing the microbial profiles in broiler chickens

The early gut microbiota of broiler chickens plays a critical role in shaping physiological functions later in life. Broilers have a limited capacity to utilize dietary fiber at an early stage of life. Fecal microbiota transplantation (FMT) can modify the gut microbial composition of broilers, potentially enhancing their fiber utilization capability. In this study, fecal samples from different chicken donors (broilers, laying hens, and broiler breeders) were collected and used for in vitro fermentation with two structurally distinct fibers, inulin and citrus pectin. FMT was then performed on newly hatched broilers, followed by additional in vitro fermentation to evaluate changes in the recipients' fiber fermentation capacity. Laying hen fecal microbiota exhibited the fastest fermentation rates for both fibers, while broilers showed the slowest. Notably, laying hens produced the highest levels of propionic acid during fermentation. These donor-specific fermentation differences were likely driven by Bacteroides, Subdoligranulum, Collinsella, Clostridium, and Bifidobacterium. The in vivo experiment demonstrated that FMT significantly altered the microbial composition and volatile fatty acid production in recipient broilers up to 14 days of age. Subsequent in vitro fermentation of the recipients' cecal content revealed that fermentation capacity was influenced by both the donor microbiota and the fiber substrate, with recipients of laying hen microbiota showing significantly enhanced propionic acid production, mirroring donor patterns. In conclusion, differences in donor fecal microbiota composition reflect their distinct capacities to utilize different fibers. Through FMT, recipient's cecal microbiota composition can be changed, and the donor's fermentative capacity is reflected in the recipients. These findings highlight the potential of early microbial interventions to improve fiber utilization in broilers, offering a promising strategy to optimize gut health.