The aim of this study was to investigate the effect of dietary replacement of soya bean meal (SBM) with faba bean (FB) and a blend of non-starch polysaccharide (NSP) degrading enzymes on the gastrointestinal function, growth performance and welfare of young turkeys (1 to 56 days of age). An experiment with a 2×2 factorial design was performed to compare the efficacy of four diets: a SBM-based diet and a diet containing FB, with and without enzyme supplementation (C, FB, CE and FBE, respectively). In comparison with groups C, higher dry matter content and lower viscosity of the small intestinal digesta were noted in groups FB. The content of short-chain fatty acids (SCFAs) in the small intestinal digesta was higher in groups FB, but SCFA concentrations in the caecal digesta were comparable in groups C and FB. In comparison with control groups, similar BW gains, higher feed conversion ratio (FCR), higher dry matter content of excreta and milder symptoms of footpad dermatitis (FPD) were noted in groups FB. Enzyme supplementation increased the concentrations of acetate, butyrate and total SCFAs, but it did not increase the SCFA pool in the caecal digesta. The enzymatic preparation significantly improved FCR, reduced excreta hydration and the severity of FPD in turkeys. It can be concluded that in comparison with the SBM-based diet, the diet containing 30% of FB enables to achieve comparable BW gains accompanied by lower feed efficiency during the first 8 weeks of rearing. Non-starch polysaccharide-degrading enzymes can be used to improve the nutritional value of diets for young turkeys, but more desirable results of enzyme supplementation were noted in the SBM-based diet than in the FB-based diet.

The digestion of polysaccharides from the wheat cultivars Caphorn and Isengrain was investigated, and the efficiency of an enzyme preparation was tested using the TNO gastrointestinal model (TIM-1). The apparent digestibility (AD) of carbohydrates was determined based on the measurement of organic matter (OM), total monosaccharides, reducing ends (RE) and end products (EP: glucose, maltose and xylobiose). The AD of the OM from Caphorn and Isengrain measured using caecectomised cockerels did not differ from that measured using TIM-1: 72·0 (sd 2·6) v. 70·6 (sd 0·6) % for Caphorn (P = 0·580) and 73·0 (sd 2·3) v. 71·1 (sd 1·9) % for Isengrain (P = 0·252). After the 6 h TIM-1 digestion, 41·4–58·9 % of the OM, RE and EP were recovered from the jejunal compartment and 18·3–27·1 % from the ileal compartment, while ileal deliveries and digestive residues constituted the remainder. A commercial enzyme cocktail tested at 0·2 μl/g of wheat improved TIM-1 digestibility of Caphorn and Isengrain polysaccharides: 3·9 % (P = 0·0203) and 3·4 % (P = 0·0058) based on the OM; 9·7 % (P < 0·0001) and 3·1 % (P = 0·031) based on the total glucose; 47·2 % (P < 0·0001) and 14·2 % (P = 0·0004) based on the RE, respectively. The enzyme cocktail improved the release of the EP for Caphorn (3·8 %, P = 0·008) but not for Isengrain ( − 0·8 %, P = 0·561). The higher efficiency of the enzyme supplementation on the digestion of Caphorn polysaccharides compared with Isengrain seems to be linked to the higher soluble carbohydrate contents and/or less ramified arabinoxylan of Caphorn.

An experimental model is described that was used for assessing in vivo effects in fowls of exogenous enzyme supplementation on the degradation of plant cell walls to metabolizable monosaccharide residues. It was based on tube-feeding U-14C-labelled cell-wall substrates, cellulose, spinach (Spinacia oleracea) or Festuca with and without enzyme treatments, and monitoring recovery of 14C radioactivity in exhaled carbon dioxide and excreta in the following 8 h. Normal digestion of cell-wall polysaccharides by endogenous microbial activity was also studied by pretreating birds with an antibiotic mixture intended to deplete their intestinal microflora. The results of this pretreatment appeared to confirm the existence of microbial degradation of cellulose in (conditioned) fowls. Judging from differences in 14CO2 production, effects of exogenous enzyme additions were greatly enhanced with all substrates by combining them with a wet pretreatment, thereby increasing the time-period available for them to act in aqueous conditions. However, estimations of digestibilities of cellulose, hemicellulose and pectin with dry and wet treatments, based on recovery of 14C in excreta, indicated that it was only cellulose digestion that was improved by the wet pretreatment. This suggests that degradation of cellulose, which appeared to be slowest, was limited by the dry treatments, whereas that of hemicellulose and pectin was not. Respective digestibilities of these three cell-wall components, from all treatments combined, were in the proportions 1:1.5:4·2.

A major benefit of supplementing non-ruminant feedstuffs with exogenous enzymes is presumed to be the degradation of plant cell-wall polysaccharides to metabolizable monosaccharide residues. In the present study, metabolic fates of (U-14C-labelled, 10 mM) glucose, galactose, mannose, xylose and arabinose were compared in the fowl, by measuring recoveries of 14C radioactivity in exhaled carbon dioxide, excreta and body tissues after administration either by wing vein (iv) or into the crop (ic). A further comparison was made with a tube-fed, enzyme-treated, U-14C-labelled cell-wall substrate, Festuca arundinacea and a final experiment tested possible competition for absorption between different cell-wall residues. Delays between iv and is treatments in recovery of 14C in CO2, which were assumed to reflect intestinal absorption, indicated that xylose was absorbed more slowly than glucose and galactose, but faster than mannose and arabinose. Total recoveries of 14C in CO2 and excreta over the whole test period indicated that metabolizabilities were highest with glucose, galactose and mannose, and lowest with arabinose. After testing, 14C recovery in caecal contents was highest with is arabinose, and recoveries in body tissues, with all sugar treatments, were in the order liver > breast and leg muscle > abdominal fat > plasma. Results with the Festuca substrate showed similar patterns of recovery in body tissues and confirmed an increase in metabolizability with addition of enzymes. The timing of the 14CO2 response with Festuca and a wet enzyme pretreatment was broadly similar to a ‘predicted Festuca’ response, based on the composition of the substrate and the measured responses with individual (ic) monosaccharides. There was no evidence of any competition for absorption or metabolism among cell-wall residues. It was concluded that glucose release from cellulose is potentially the most important product of cell-wall degradation to contribute to enzyme enhancement of metabolizable energy.

A total of 360 I-d-old broiler chickens were fed on a diet based on rye and wheat in equal proportions without or with supplementation of increasing levels (0.11, 0.22, 0.44 and 0.88 g/kg) of a technical enzyme preparation containing pentosanase and β-glucanase activities. In vitro investigations revealed that the enzyme preparation solubilized pentosans, increasing the relative viscosity of buffer extracts from enzyme-supplemented diets. Enzyme supplementation generally improved body-weight by approximately 27% at day 15 and 15% at day 27, increased feed intake by 15 and 8% respectively, and improved feed conversion efficiency by 10 and 5% respectively. There was also a decreased occurrence of sticky droppings. Enzyme supplementation increased the digestibility of organic matter, crude protein (nitrogen x 6.25) and starch measured in the last third of the small intestine, and of organic matter and crude fat measured in excreta. Solubilization of insoluble pentosans by the enzyme included led to negative digestibility values for soluble pentosans in the small intestine at the higher levels of supplementation. Most of the dietary fibre degradation observed occurred before the middle section of the small intestine, with some degradation of soluble fibre in the caeca and colon. The solubilization and disruption of feed endosperm cell walls by enzyme supplementation probably was primarily responsible for the observed improvements in digestibility and production results.