Effects of Added Dietary Fiber and Rearing System on the Gut Microbial Diversity and Gut Health of Chickens

Abstract

It is of merit to study the appropriate amount of dietary fiber to add to free-range chickens’ feed to improve their microbial diversity and gut health in times of plant fiber deprivation. Lignocellulose is a useful source of dietary fiber, and its positive effects on the growth performance and laying performance of chickens has already been proven. However, few researchers have researched the effects of adding it on the gut microbiota of chickens. In this research, we added three different levels of eubiotic lignocellulose (0%, 2%, and 4%) to the feed of caged and free-range Bian chickens from September to November, aiming to observe the effects of added dietary fiber and different rearing systems on the gut microbial diversity and gut health of chickens, as well as to determine an appropriate amount of lignocellulose. The results showed that adding dietary fiber increased the thickness of the cecum mucus layer and the abundance of Akkermansia and Faecalibacterium in caged chickens, and 4% lignocellulose was appropriate. In addition, adding lignocellulose increased the microbial diversity and the abundance of the butyrate-producing bacteria Faecalibacterium and Roseburia in fee-range chickens. The α-diversity and the length of the small intestine with 2% lignocellulose in free-range chickens were better than with 2% lignocellulose in caged chickens. Maybe it is necessary to add dietary fiber to the feed of free-range chickens when plant fibers are lacking, and 2% lignocellulose was found to be appropriate in this experiment. In addition, compared with caged chickens, the free-range chickens had a longer small intestine and a lower glucagon like peptide-1 (GLP-1) level. The significant difference of GLP-1 levels was mainly driven by energy rather than short chain fatty acids (SCFAs). There was no interaction between added dietary fiber and the rearing system on SCFAs, cecum inner mucus layer, and GLP-1.

Lignocellulose as an insoluble fiber source in poultry nutrition: a review

“…Moreover, increasing concentrations of dietary LC decreased counts of Escherichia/Hafnia/Shigella [ 25 ]. Four recent studies using a potential more fermentable LC product also displayed conflicting results regarding the effect of dietary LC on the gut microbiota in broilers and laying hens [ 22 , 24 , 35 , 86 ]. The feeding of isoenergetic, isonitrogenous diets containing 2% and 4% LC increased the cecal microbial diversity and the abundance of butyrate-producing bacteria in free-range chickens, while the luminal concentration of butyrate, acetate and propionate was not affected [ 86 ].…”

“…Four recent studies using a potential more fermentable LC product also displayed conflicting results regarding the effect of dietary LC on the gut microbiota in broilers and laying hens [ 22 , 24 , 35 , 86 ]. The feeding of isoenergetic, isonitrogenous diets containing 2% and 4% LC increased the cecal microbial diversity and the abundance of butyrate-producing bacteria in free-range chickens, while the luminal concentration of butyrate, acetate and propionate was not affected [ 86 ]. In contrast, broilers and laying hens fed diets which were supplemented with 0.8% and 1% LC, showed no alterations in the overall cecal microbial diversity [ 22 , 35 ].…”

The relationship among gut microbiota, short-chain fatty acids, and intestinal morphology of growing and healthy broilers

“…(2016) found that the changes of fermentation of end products are likely to be associated with the density of the resident bacteria, and the cecum has greatest taxonomic diversity and abundance in the present study, which were in agreement with the previous studies ( Gong et al., 2007 ; Choi et al., 2014 ). In addition, the diet composition and rearing system are also the important influences of bacteria in the gut, and thus, SCFAs will change as diet component or rearing system varies ( Heinritz et al., 2016 ; Hou et al., 2020 ). Therefore, the effects of other types of diets or rearing system on gut microbiota, SCFAs, and intestinal morphology of broilers need to be further studied.…”

Campylobacter sp.: Pathogenicity factors and prevention methods—new molecular targets for innovative antivirulence drugs?

“…Other plant constituents contribute to influencing the microbiome and it is known that indigestible dietary fibers such as lignin can change the microbial composition (Hou et al 2020).…”