In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting...In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting protein degradation to avoid excess release of ammonia, and activation of fiber digestion. The main approach has been the use of dietary supplements. Since growth-promoting antibiotics were banned in European countries in2006, safer alternatives including plant-derived materials have been explored. Plant oils, their component fatty acids,plant secondary metabolites and other compounds have been studied, and many originate or are abundantly available in Asia as agricultural byproducts. In this review, the potency of selected byproducts in inhibition of methane production and protein degradation, and in stimulation of fiber degradation was described in relation to their modes of action. In particular, cashew and ginkgo byproducts containing alkylphenols to mitigate methane emission and bean husks as a source of functional fiber to boost the number of fiber-degrading bacteria were highlighted. Other byproducts influencing rumen microbiota and fermentation profile were also described. Future application of these feed and additive candidates is very dependent on a sufficient, cost-effective supply and optimal usage in feeding practice.展开更多
Dietary fiber-degrading enzyme supplementation in broilers aims at off-setting the anti-nutritive effect of non-starch polysaccharides and at promoting broiler health.Recently,we demonstrated that xylanase/glucanase a...Dietary fiber-degrading enzyme supplementation in broilers aims at off-setting the anti-nutritive effect of non-starch polysaccharides and at promoting broiler health.Recently,we demonstrated that xylanase/glucanase addition in wheat-based diet improved nutrient digestibility,arabinoxylan fermentability and broiler growth.Conversely,maize arabinoxylan was found to be recalcitrant to xylanase action.These findings suggested that enzyme-mediated improvement of nutrient digestion and carbohydrate fermentation depended on the cereal type present in the diet,and may have contributed to broiler growth.Hence,we aimed at further investigating the link between dietary enzymes and carbohydrate fermentation in broilers,by studying the impact of enzyme supplementation in cereal-based diets,to the microbial communities in the ileum and ceca of broilers.For that purpose,96 one-day-old male broilers were randomly reared in two pens and received either wheat-based or maize-based starter and grower diets.At d 20,the broilers were randomly assigned to one out of four dietary treatments.The broilers received for 8 d the wheat-based or maize-based finisher diet as such(Control treatments;WC,MC)or supplemented with a xylanase/glucanase combination(Enzyme treatments;WE,ME).At d 28,samples from the digestive tract were collected,and the ileal and cecal microbiota composition was determined by 16S ribosomal RNA gene amplicon sequencing.A similar phylogenetic(alpha)diversity was observed among the four treatments,both in the ileal and the cecal samples.Furthermore,a similar microbial composition in the ileum(beta diversity)was observed,with lactobacilli being the predominant community for all treatments.In contrast,both cereal type and enzyme supplementation were found to influence cecal communities.The type of cereal(i.e.,wheat or maize)explained 47% of the total variation in microbial composition in the ceca.Further stratifying the analysis per cereal type revealed differences in microbiota composition between WC and WE,but not between MC and ME.Furthermore,the prevalence of beneficial genera,such as Faecalibacterium and Blautia,in the ceca of broilers fed wheat-based diets coincided with arabinoxylan accumulation.These findings indicated that fermentable arabinoxylan and arabinoxylo-oligosaccharides released by dietary xylanase may play an important role in bacterial metabolism.展开更多
基金supported by JSPS KAKENHI Grant Numbers JP20380146,JP23380156,JP23658213,JP26660207
文摘In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting protein degradation to avoid excess release of ammonia, and activation of fiber digestion. The main approach has been the use of dietary supplements. Since growth-promoting antibiotics were banned in European countries in2006, safer alternatives including plant-derived materials have been explored. Plant oils, their component fatty acids,plant secondary metabolites and other compounds have been studied, and many originate or are abundantly available in Asia as agricultural byproducts. In this review, the potency of selected byproducts in inhibition of methane production and protein degradation, and in stimulation of fiber degradation was described in relation to their modes of action. In particular, cashew and ginkgo byproducts containing alkylphenols to mitigate methane emission and bean husks as a source of functional fiber to boost the number of fiber-degrading bacteria were highlighted. Other byproducts influencing rumen microbiota and fermentation profile were also described. Future application of these feed and additive candidates is very dependent on a sufficient, cost-effective supply and optimal usage in feeding practice.
文摘Dietary fiber-degrading enzyme supplementation in broilers aims at off-setting the anti-nutritive effect of non-starch polysaccharides and at promoting broiler health.Recently,we demonstrated that xylanase/glucanase addition in wheat-based diet improved nutrient digestibility,arabinoxylan fermentability and broiler growth.Conversely,maize arabinoxylan was found to be recalcitrant to xylanase action.These findings suggested that enzyme-mediated improvement of nutrient digestion and carbohydrate fermentation depended on the cereal type present in the diet,and may have contributed to broiler growth.Hence,we aimed at further investigating the link between dietary enzymes and carbohydrate fermentation in broilers,by studying the impact of enzyme supplementation in cereal-based diets,to the microbial communities in the ileum and ceca of broilers.For that purpose,96 one-day-old male broilers were randomly reared in two pens and received either wheat-based or maize-based starter and grower diets.At d 20,the broilers were randomly assigned to one out of four dietary treatments.The broilers received for 8 d the wheat-based or maize-based finisher diet as such(Control treatments;WC,MC)or supplemented with a xylanase/glucanase combination(Enzyme treatments;WE,ME).At d 28,samples from the digestive tract were collected,and the ileal and cecal microbiota composition was determined by 16S ribosomal RNA gene amplicon sequencing.A similar phylogenetic(alpha)diversity was observed among the four treatments,both in the ileal and the cecal samples.Furthermore,a similar microbial composition in the ileum(beta diversity)was observed,with lactobacilli being the predominant community for all treatments.In contrast,both cereal type and enzyme supplementation were found to influence cecal communities.The type of cereal(i.e.,wheat or maize)explained 47% of the total variation in microbial composition in the ceca.Further stratifying the analysis per cereal type revealed differences in microbiota composition between WC and WE,but not between MC and ME.Furthermore,the prevalence of beneficial genera,such as Faecalibacterium and Blautia,in the ceca of broilers fed wheat-based diets coincided with arabinoxylan accumulation.These findings indicated that fermentable arabinoxylan and arabinoxylo-oligosaccharides released by dietary xylanase may play an important role in bacterial metabolism.
