Gastrointestinal Microbiota and Their Manipulation for Improved Growth and Performance in Chickens

Abstract

The gut of warm-blooded animals is colonized by microbes possibly constituting at least 100 times more genetic material of microbial cells than that of the somatic cells of the host. These microbes have a profound effect on several physiological functions ranging from energy metabolism to the immune response of the host, particularly those associated with the gut immune system. The gut of a newly hatched chick is typically sterile but is rapidly colonized by microbes in the environment, undergoing cycles of development. Several factors such as diet, region of the gastrointestinal tract, housing, environment, and genetics can influence the microbial composition of an individual bird and can confer a distinctive microbiome signature to the individual bird. The microbial composition can be modified by the supplementation of probiotics, prebiotics, or synbiotics. Supplementing these additives can prevent dysbiosis caused by stress factors such as infection, heat stress, and toxins that cause dysbiosis. The mechanism of action and beneficial effects of probiotics vary depending on the strains used. However, it is difficult to establish a relationship between the gut microbiome and host health and productivity due to high variability between flocks due to environmental, nutritional, and host factors. This review compiles information on the gut microbiota, dysbiosis, and additives such as probiotics, postbiotics, prebiotics, and synbiotics, which are capable of modifying gut microbiota and elaborates on the interaction of these additives with chicken gut commensals, immune system, and their consequent effects on health and productivity. Factors to be considered and the unexplored potential of genetic engineering of poultry probiotics in addressing public health concerns and zoonosis associated with the poultry industry are discussed.

Necrotic Enteritis in Broiler Chickens: A Review on the Pathogen, Pathogenesis, and Prevention

“…Probiotics are defined as “live microbial feed supplements which, when administered in adequate amounts, beneficially affect the host animal by improving the gut microbial balance” [ 179 ]. The proposed modes of action of probiotics are: (1) competitive exclusion and antagonism, (2) improving the host intestinal health and integrity, (3) improving digestion and absorption, (4) enhancing growth and performance, and (5) immunomodulation [ 180 ]. An ideal probiotic should be non-pathogenic, of host origin, free of adverse side effects, should have demonstrated a beneficial effect on the host, be resistant to gastric acid and bile salts, be able to adhere to the host gastrointestinal mucosa, competitively exclude pathogenic bacterial colonization, be sensitive to antibiotics, positively modulate host immune functions, and be able to withstand processing and storage conditions [ 181 , 182 , 183 ].…”

The Development of Gut Microbiota and Its Changes Following C. jejuni Infection in Broilers

“…The gastrointestinal tract of poultry species is highly populated with microorganisms that exist in a symbiotic relationship with the host [ 1 ]. These complex microbial communities benefit the host by regulating digestion and synthesizing bile acids, vitamins, and short-chain fatty acids [ 2 ].…”

Dietary rosemary extract modulated gut microbiota and influenced the growth, meat quality, serum biochemistry, antioxidant, and immune capacities of broilers

“…The gut microbial homeostasis was required for the development and maturation of the animals, which affected a wide range of physiology aspects, including growth performance, production performance, nutrient digestibility, immune function, and antioxidative capacity ( Sommer and Bäckhed, 2013 ; Fathima et al, 2022 ). Previous literature reported that RE had the potential to reshape the gut microflora in mice under stressed conditions ( Guo et al, 2018 ; He et al, 2022 ), and rosemary leaf meal could increase the population of Lactobacillus but reduce the population of E. coli and Salmonella ( Ogwuegbu et al, 2021 ).…”