Cassava cell wall characterization and degradation by a multicomponent NSP-targeting enzyme (NSPase).

Cassava (Manihot esculenta Crantz) is considered the third most important source of calories in tropical regions. Up to one third of cassava harvested worldwide is used in livestock production. The focus of this study was to characterize cassava cell wall structure to provide knowledge for a better application of cassava as an energy source in monogastric animal feed. A total of five cassava samples from different feed mills in South East Asia were investigated. On a dry matter basis, the cassava cell walls contained, on average, 640 mg g-1 glucose, 140 mg g-1 galactose, 50 mg g-1 mannose, 80 mg g-1 xylose, 60 mg g-1 arabinose, 10 mg g-1 fucose and 20 mg g-1 rhamnose. RONOZYME VP (DSM Nutritional Products, Switzerland), a non-specific multicomponent non-starch polysaccharide (NSP) degrading enzyme (NSPase) product from Aspergillus aculeatus, solubilized about 10% of cassava NSP content during 4 h incubations at 40 °C and pH 5. There was notable solubilization of polymers containing uronic acids, galactose, arabinose and rhamnose. Immuno-microscopy imaging indicated the solubilization of pectin, galactan and xyloglucan polysaccharides from cassava cell wall. As a consequence, the starch granules became more available to exogenous α-amylase degradation.

Nutritive value of enzyme-supplemented carinata meal for growing pigs.

Carinata meal is increasingly available for livestock feeding. However, the effects of supplemental phytase and fiber degrading enzymes on nutritive value of carinata meal for pigs have not been reported. Objective of the study was to evaluate the standardized ileal digestibility (SID) of amino acid (AA), and digestible energy (DE) and net energy (NE) values of phytase- and fiber-degrading enzymes-supplemented carinata meal for growing pigs. Ten ileal-cannulated pigs (initial body weight = 53.9 ± 4.76 kg) were fed 4 diets in a replicated 4 × 4 Latin square design with two additional columns to give 10 replicates per diet. Diets included a corn-soybean meal (SBM)-based basal diet, basal diet with 25% carinata meal, basal diet with 25% carinata meal plus phytase at 2,000 FTU/kg and multi-carbohydrase at 0.2 g/kg, and in addition a nitrogen-free diet. The multicarbohydrase supplied 4 units of xylanase, 10 units of ß-glucanase, and 1,000 units of pectinase per kilogram of diet. The ratio of corn to SBM and soybean oil in carinata meal-containing diets was identical to that in the corn-SBM-based basal diet to allow calculation of AA and energy digestibility of carinata meal by the difference method. On a dry matter basis, carinata meal contained 50.2% crude protein, 0.88% ether extract, 15.37% acid detergent fiber, 1.82% Lys, 0.96% Met, 1.89% Thr, and 0.64% Trp, respectively. The SID of Lys, Met, Thr, and Trp for carinata meal were 51.4%, 82.2%, 65.9%, and 85.9%, respectively. The DE and NE values for carinata meal were 3,427 and 1,828 kcal/kg of dry matter, respectively. Supplementation of a combination of phytase and multicarbohydrase did not affect the apparent ileal digestibility of AA and SID of AA for the corn-SBM-carinata meal-based diet, and for the carinata meal. However, the combination of phytase and multicarbohydrase did improve (P < 0.05) apparent total tract digestibility, and DE and NE values for carinata meal by 9.4%, 9.5%, and 12.4%, respectively. In conclusion, the enzymes used in the current study could be added in carinata meal-based diets for growing pigs to improve the energy value.

Superior Growth Rates in Broilers Fed Wheat with Low In Vitro Feed-Xylanase Inhibition.

Grain-batch variation in xylanase-inhibitor levels may account for variations in the efficacy of feed xylanase supplementation. This would make inhibition an important quality parameter in the routine analysis of feedstuffs. Two analytical procedures for testing feedstuffs against specific xylanases were researched: the high-throughput viscosity-pressure assay (ViPr) and the extraction-free remazol-brilliant-blue-beechwood-xylan (RBBX) assay. Thirty-two wheat cultivars were analyzed for inhibition of a commercial xylanase, Ronozyme WX. Four cultivars were selected for a feeding experiment in which the growth of 1440 broilers from ages 7-33 days was monitored. The treatments resulted up to 7 % difference (day 14) in broiler weight . The cultivar choice had an effect throughout the experiment ( p < 0.05). The performance ranking of the treatments corresponded better to xylanase inhibition than to crude-protein content or nonstarch-polysaccharide content. Wheat-grain xylanase-inhibitor content is therefore a highly relevant quality parameter when broiler diets are supplemented with feed xylanase.

In vitro and in vivo degradation of myo-inositol hexakisphosphate by a phytase from Citrobacter braakii.

Phytases (EC 3.1.3) are widely used in animal feed to increase the availability of phosphorus and decrease the anti nutritive effect of myo-inositol hexakisphosphate (InsP6). The aim of this work was to investigate the stereospecific degradation of InsP6 in vitro and in vivo by a phytase from Citrobacter braakii (C. braakii), and to study gastric survival of the phytase as well as the site of action in the gastrointestinal tract. The in vitro results showed that the C. braakii phytase belongs to the group of 6-phytases (EC 3.1.3.26). However, in approximately one out of 10 instances the phytase initiated hydrolysis at the D-3 (L-1) position, demonstrating that phytase specificity is not unambiguous. Following the main degradation pathway, InsP6 was degraded by stepwise removal of the phosphate groups on positions 6/1/5. The stereospecificity was found to be similar under in vitro and in vivo conditions. The phytase was found to be stable in the gastric environment and to be active in the stomach and possibly also in the proximal small intestine. While InsP4 was accumulated under in vitro conditions this was not the case in vivo, where both InsP5 and InsP4 were seen to be hydrolysed in the small intestine, possibly as a combined action of the C. braakii phytase and endogenous phosphatases present in the mucosa. The ability of the C. braakii phytase to focus its activity on degrading InsP6 to InsP4 is believed to be a favourable complement to the endogenous phosphatases.

Peniophora lycii phytase is stabile and degrades phytate and solubilises minerals in vitro during simulation of gastrointestinal digestion in the pig.

BACKGROUND: Microbial phytases (EC 3.1.3) are widely used in diets for monogastric animals to hydrolyse phytate present in the feed and thereby increase phosphorus and mineral availability. Previous work has shown that phytate solubility is strongly affected by calcium in the feed and by pH in the gastrointestinal (GI) tract, which may have an effect on phytase efficacy. An in vitro model simulating the GI tract of pigs was used to study the survival of Peniophora lycii phytase and the effect of the phytase on phytate degradation, inositol phosphate formation and mineral solubilisation during in vitro digestion of a 30:70 soybean meal/maize meal blend with different calcium levels. RESULTS: The phytase retained 76 and 80% of its initial activity throughout the gastric in vitro digestion. Total phytate hydrolysis by P. lycii phytase was in the same range at total calcium levels of 1.2 and 6.2 mg g(-1) dry matter (DM), despite very large differences in phytate solubility at these calcium levels. However, at 11.2 and 21.2 mg Ca g(-1) DM, phytate hydrolysis was significantly lower. The amount of soluble mineral was generally increased by P. lycii phytase. CONCLUSION: Stability of P. lycii phytase during gastric digestion was not found to be critical for phytate hydrolysis. Furthermore, original phytate solubility was not an absolute requirement for phytate degradation; phytate solubility seemed to be in a steady state, allowing insoluble phytate to solubilise as soluble phytate was degraded. This is new and interesting knowledge that adds to the current understanding of phytate-phytase interaction. Copyright © 2007 Society of Chemical Industry.