Abstract
Improper usage of antibiotics in poultry production is a great threat to the ecosystem because their residues can enter into the food chain or leach into soil or water systems and increase antibiotic resistance risks. Hence, direct-fed microbials (DFMs) have gained recognition as a sustainable and viable alternative to antibiotics in poultry production, capitalizing on the relationship between microbial genetics, host genomics, and gut microbiota. This review delves into the genetic and host genomic mechanisms through DFMs effects including the enhancement of nutrient metabolism, modulation of gut microbiota and strengthening of the host immunity. The revolution of multi-omics has participated in the identification of probiotic strains with desirable traits and revealed their impact on host gene expression, particularly in genes related to intestinal health, such as tight junction proteins and mucins. Furthermore, the review summarizes the benefits of using DFMs in poultry production, the factors affecting their efficacy and their challenges and limitations. Future research integrating host and microbial genomics, along with precision microbiome engineering, holds promise for maximizing the potential of DFMs in advancing sustainable poultry farming practices.
