Influence of dietary carbohydrases, individually or in combination with phytase or an acidifier, on performance, gut morphology and microbial population in broiler chickens fed a wheat-based diet

The objective of this study was to examine the effects of dietary carbohydrases(xylanase and b-glucanase; XG), individually or in combination with phytase or acidifier on the growth performance, carcass attributes, intestinal microbial counts and morphology in broiler chickens fed a wheat-based diet. A total of 240 one-day-old male broiler chicks were randomly allocated into 4 treatment groups with 6 replicates of 10 birds each. The dietary treatments included a basal diet, the basal diet with an enzyme complex containing XG, XG plus a microbial phytase(XG + P) and XG plus acidifier(XG + A). The results indicated that feed conversion ratio(FCR) was improved in broiler chickens which received XG + A during the entire production period(1 to 35 d) of the trial(P < 0.05). The broiler chickens fed XG + P had lower feed intake compared with the control group at 29 to 35 d of age. The experimental treatments had no effect on the body weight gain of broiler chickens. In carcass traits, except for spleen(P < 0.05), the dietary treatments had no effects on the carcass characteristics of broiler chickens. The birds which received diets supplemented with XG and XG + A had a lower weight of the spleen compare with the control. Addition of XG in combination with phytase(XG + P) resulted in a decrease in ileal enumeration of Escherichia coli at 35 d of age(P < 0.05). However, dietary treatments did not alter the population of ileal Lactobacilli in broiler chickens. Supplementing carbohydrases with phytase and acidifier(XG + P and XG + A) significantly increased the intestinal villus length at 35 d of age(P < 0.05). In conclusion, the present study demonstrated that supplementation of the wheat-based diet with a combination with carbohydrases and acidifier(XG + A) improves FCR in broiler chickens. Furthermore, combinations of carbohydrases with phytase(XG + P) and with acidifier(XG + A) decrease the E. coli counts and increase the villus length in broiler chickens.

Dietary fibre effects and the interplay with exogenous carbohydrases in poultry nutrition

A comprehensive understanding of the role of dietary fibre in non-ruminant animal production is elusive.Equivocal and conflated definitions of fibre coupled with significant analytical complexity,interact with poorly defined host and microbiome relationships.Dietary fibre is known to influence gut development,feed intake and passage rate,nutrient absorption,microbiome taxonomy and function,gut p H,endogenous nutrient loss,environmental sustainability,animal welfare and more.Whilst significant gaps persist in our understanding of fibre in non-ruminant animal production,there is substantial interest in optimizing the fibre fraction of feed to induce high value phenotypes such as improved welfare,live performance and to reduce the environmental footprint of animal production systems.In order to achieve these aspirational goals,it is important to tackle dietary fibre with the same level of scrutiny as is currently done for other critical nutrient classes such as protein,minerals and vitamins.The chemical,mechanical and nutritional role of fibre must be explored at the level of monomeric sugars,oligosaccharides and polysaccharides of varying molecular weight and decoration,and this must be in parallel to standardisation of analytical tools and definitions for speciation.To further complicate subject,exogenous carbohydrases recognise dietary fibre as a focal substrate and have varying capacity to generate lower molecular weight carbohydrates that interact differentially with the host and the enteric microbiome.This short review article will explore the interactive space between dietary fibre and exogenous carbohydrases and will include their nutritional and health effects with emphasis on functional development of the gut,microbiome modulation and host metabolism.

Non-starch polysaccharide-degrading enzymes may improve performance when included in wheat- but not maize-based diets fed to broiler chickens under subclinical necrotic enteritis challenge

The present study investigated whether supplementing fibre-degrading enzymes can ameliorate the severity of subclinical necrotic enteritis(NE)in broiler chickens offered wheat-or maize-based diets.A total of 1,544 mixed-sex broiler chickens were assigned to 16 experimental treatments as a 2×2×4 factorial arrangement of treatments.The factors were the following:NE challenge,yes or no;diet type,wheat-or maize-based;and enzyme supplementation,control(no enzyme),family 10 xylanase(XYN10),family 11 xylanase(XYN11)or b-mannanase(MAN).Each treatment was replicated 6 times,with 16 birds per replicate pen.A three-way challenge×diet type×enzyme interaction occurred for body weight at 21 d of age(P=0.025)and overall feed conversion ratio(P=0.001).In the non-challenged birds fed the wheat-based diet,supplementing MAN increased d 21 body weight compared to the control.In challenged birds fed the maize-based diet,supplemental XYN11 impeded body weight and overall FCR compared to the control.Birds offered the maize-based diet presented heavier relative gizzard weights at both 16 and 21 d of age(P<0.001)and reduced liveability(P=0.046)compared to those fed the wheatbased diet.Enzyme supplementation reduced ileal and jejunal digesta viscosity at 16 d of age only in birds fed the wheat-based diet(P<0.001).XYN11 increased ileal digesta viscosity in birds fed the maizebased diet,and MAN reduced it in birds fed the wheat-based diet at 21 d of age(P=0.030).Supplementing XYN11 improved ileal soluble non-starch polysaccharides(NSP)digestibility in birds fed the wheat-based diet compared to non-supplemented birds(P<0.001).Birds fed the wheat-based diet displayed a higher abundance of Bifidobacterium,Lactobacillus and Enterobacteriaceae and butyric acid in the caeca at 16 d of age compared to birds fed the maize-based diet(P<0.05).In conclusion,supplemental XYN11 exacerbated the negative impact of NE on growth performance in birds fed the maizebased diet.Supplementing wheat-based diets with fibre-degrading enzymes ameliorates production losses induced by NE.