Effects of gastric pH on the activity of exogenous pentosanase and the effect of pentosanase supplementation of the diet on the performance of growing-finishing pigs

Effects of Different Proteases on Protein Digestion In Vitro and In Vivo and Growth Performance of Broilers Fed Corn-Soybean Meal Diets

This study was conducted to investigate the effects of different proteases alone or in combination on protein digestibility of broilers. In vitro, the properties of four proteases in broilers, including acidic protease (AcP), alkaline protease (AlP), neutral protease (NeP) and keratinase (Ker), on endogenous protease activity and their effects on protein digestibility of common ingredients in broiler diets were investigated using a gut-mimicking model. In vivo, 640 1-day-old male broilers were randomly divided into 8 groups of 10 with 8 replicates of 10 birds per replicate cage. Eight dietary treatments included a corn-soybean meal basal diet (control), and the basal diet with 1.6 U AcP/g, 0.8 U NeP/g, 0.8 U AlP/g, 0.4 U Ker/g, 1.6 U AcP/g + 0.8 U NeP/g, 1.6 U AcP/g + 0.8 U AlP/g, or 1.6 U AcP/g + 0.4 U Ker/g added. The experiment lasted for 31 days. The results showed that the optimum pH values of AcP, NeP, AlP and Ker were 3.0, 9.0, 11.0 and 11.0 in vitro, respectively. Ker recovery proportion was 37.68% at pH 3.3-6.2. AcP alone or in combination with NeP, AlP or Ker increased in vitro crude protein digestibility (IVCPD) and decreased ileal apparent digestibility of crude protein in 31-day-old broilers (p < 0.05). All protease supplementation reduced the ileal apparent digestibility of amino acids compared to the control (p < 0.05). Acidic protease had a positive effect on trypsin and chymotrypsin activities, while AlP and Ker showed a negative effect. In vivo, average daily gain and average daily feed intake were significantly (p < 0.05) increased in broiler diets supplemented with AcP compared to the control group. When adding exogenous proteases to broiler diets, their sensitivity to digestive pH and their negative effects on endogenous protease activity, dosage and combination effects should be taken into account. In addition, the properties and dosage of proteases and the protein level in the feed should be considered.

In vitro evaluation of efficacy of nonstarch polysaccharides enzymes on wheat by simulating the avian digestive tract

In this study, the efficacy of different nonstarch polysaccharide (NSP) enzyme sources on wheat ingredients and wheat basal diets in vitro were evaluated by simulating the avian digestive tract. In Exp. 1, pH level was increased from 2.0 to 8.0 by simulating the avian digestive tract. The relative enzyme activities of xylanase A, B, and C and β-glucanase X at pH 3.0-3.5 were higher (P < 0.05) than those at pH 2.0 or 7.0-8.0. The optimal pH levels of 3.5 and 7.0 were screened by simulating the proventriculus and small intestine, respectively to evaluate the efficacy of NSP enzyme on wheat sources. In Exp. 2, wheat 1 contained the highest content of NSP fractions and the lowest digestibility in vitro dry matter (IVDMD) and energy (IVED) in wheat samples. Therefore, wheat 1 was selected for hydrolysis research under different NSP enzyme sources and levels (1,500, 4,500, 13,500, 40,500, 121,500 U xylanase/kg and 250, 500, 1,000, 2,000, 4,000 U β-glucanase/kg) in vitro. The hydrolysis of wheat on the basis of the released reducing sugar content was determined by xylanase sources A > B > C (P < 0.05) and β-glucanase sources of X > Y (P < 0.05). On the basis of the hydrolysis, the optimum dose of xylanase A and β-glucanase X were 40,500 U/kg and 2,000 U/kg, respectively. Subsequently, the completely randomized designs involving 2 NSP enzymes treatments × 2 endogenous digestive enzymes treatments (Exp. 3), as well as 2 wheat basal diets × 2 NSP enzymes treatments (Exp. 4) were used to evaluate the efficacy of NSP enzymes on dietary nutrient digestibility. The addition of NSP enzymes (40,500 U xylanase A/kg and 2,000 U β-glucanase X/kg) increased the IVDMD and IVED of wheat 1 without endogenous enzymes (P < 0.05), while the IVDMD and IVED of wheat 1 with endogenous enzyme were only slightly increased (P > 0.05). The addition of NSP enzymes could increase the IVDMD and IVED of corn-wheat-soybean meal diet (P < 0.05), but had no effect on those of wheat-cottonseed meal rapeseed meal diet (P > 0.05). In conclusion, xylanase and β-glucanase additions could effectively eliminate the adverse effects on wheat and wheat basal diets at the optimal pH levels of 3.5 and 7.0 by simulating the proventriculus and small intestine parts, respectively. The efficacy of NSP enzymes was influenced by the enzyme sources, dietary type, and the interaction of endogenous enzymes.

Increasing hybrid rye level substituting wheat grain with or without enzyme on growth performance and carcass traits of growing-finishing barrows and gilts

New European, fall-planted hybrid rye grown in western Canada is more resistant to ergot and fusarium and has lower content of anti-nutritional factors than common rye. We evaluated the effect of feeding increasing hybrid rye level substituting wheat grain and non-starch polysaccharide (NSP) enzyme inclusion in diets fed to growing-finishing pigs raised under western Canadian commercial conditions. In total, 1,008 pigs (~44 kg body weight [BW]) housed in 48 pens by sex, 21 pigs per pen, were fed diets with one of three rye (var. KWS Bono; KWS LOCHOW GMBH) inclusion levels substituting wheat grain: low (L; one-third of wheat replaced), medium (M; two-thirds of wheat replaced), or high (H; most wheat replaced), either without (WO) or with (W) enzyme inclusion (280 units of β-glucanase and 900 units of xylanase per kilogram feed; Endofeed W DC; GNC Bioferm) over four growth phases (Grower 2: d 0 to 22, Grower 3: d 23 to 42, Finisher 1: d 43 to 63, Finisher 2: d 64 to slaughter). Pen BW, feed added, and orts were measured on d 0, 22, 42, 63, 76, 91, and at slaughter weight (130 kg). Warm carcasses were weighed and graded (Destron). BW was not affected by either increasing hybrid rye level substituting wheat grain or enzyme inclusion throughout the trial. For the entire trial (d 0 to 76), pigs fed increasing hybrid rye level substituting wheat grain had decreased (P < 0.050) average daily feed intake (ADFI; L 3.05, M 2.98, H 2.91 kg/d) and average daily weight gain (ADG; L 1.01, M 1.00, H 0.97 kg/d). Enzyme inclusion did not affect ADFI but tended (P = 0.080) to increase ADG (WO 0.98, W 1.00 kg/d). Enzyme inclusion improved (P < 0.050) gain-to-feed ratio only in pigs fed the H rye level. Most carcass traits were not affected by either increasing hybrid rye level substituting wheat grain or enzyme inclusion. Increasing dietary hybrid rye level substituting wheat grain increased (P < 0.001) cost per tonne of feed (L 240.28, M 241.28, H 242.20 Can$/kg), but did not affect feed cost per pig or per kilogram BW gain. Enzyme inclusion increased (P < 0.001) cost per tonne of feed (WO 240.36, W 242.15 Can$/kg), but feed cost per pig (WO 82.14, W 80.44 Can$ per pig) and per kilogram BW gain (WO 0.96, W 0.94 Can$/kg gain) were reduced (P < 0.050). In conclusion, fall-planted hybrid rye can completely replace wheat grain in grower-finisher pig diets without affecting feed efficiency, feed cost per pig or feed cost per kilogram BW gain. Inclusion of NSP enzyme would be recommended for diets including high rye levels to improve feed efficiency and ADG.

Insight into Enzymatic Degradation of Corn, Wheat, and Soybean Cell Wall Cellulose Using Quantitative Secretome Analysis of Aspergillus fumigatus

Lignocelluloses contained in animal forage cannot be digested by pigs or poultry with 100% efficiency. On contrary, Aspergillus fumigatus, a saprophytic filamentous fungus, is known to harbor 263 glycoside hydrolase encoding genes, suggesting that A. fumigatus is an efficient lignocellulose degrader. Hence the present study uses corn, wheat, or soybean as a sole carbon source to culture A. fumigatus under animal physiological condition to understand how cellulolytic enzymes work together to achieve an efficient degradation of lignocellulose. Our results showed that A. fumigatus produced different sets of enzymes to degrade lignocelluloses derived from corn, wheat, or soybean cell wall. In addition, the cellulolytic enzymes produced by A. fumigatus were stable under acidic condition or at higher temperatures. Using isobaric tags for a relative and absolute quantification (iTRAQ) approach, a total of ∼600 extracellular proteins were identified and quantified, in which ∼50 proteins were involved in lignocellulolysis, including cellulases, hemicellulases, lignin-degrading enzymes, and some hypothetical proteins. Data are available via ProteomeXchange with identifier PXD004670. On the basis of quantitative iTRAQ results, 14 genes were selected for further confirmation by RT-PCR. Taken together, our results indicated that the expression and regulation of lignocellulolytic proteins in the secretome of A. fumigatus were dependent on both nature and complexity of cellulose, thus suggesting that a different enzyme system is required for degradation of different lignocelluloses derived from plant cells. Although A. fumigatus is a pathogenic fungus and cannot be directly used as an enzyme source, as an efficient lignocellulose degrader its strategy to synergistically degrade various lignocelluloses with different enzymes can be used to design enzyme combination for optimal digestion and absorption of corn, wheat, or soybean that are used as forage of pig and poultry.

Alternatives to antibiotics as growth promoters for use in swine production: a review

In the past two decades, an intensive amount of research has been focused on the development of alternatives to antibiotics to maintain swine health and performance. The most widely researched alternatives include probiotics, prebiotics, acidifiers, plant extracts and neutraceuticals such as copper and zinc. Since these additives have been more than adequately covered in previous reviews, the focus of this review will be on less traditional alternatives. The potential of antimicrobial peptides, clay minerals, egg yolk antibodies, essential oils, eucalyptus oil-medium chain fatty acids, rare earth elements and recombinant enzymes are discussed. Based on a thorough review of the literature, it is evident that a long and growing list of compounds exist which have been tested for their ability to replace antibiotics as feed additives in diets fed to swine. Unfortunately, the vast majority of these compounds produce inconsistent results and rarely equal antibiotics in their effectiveness. Therefore, it would appear that research is still needed in this area and that the perfect alternative to antibiotics does not yet exist.

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.

The degradation of phytate by microbial and wheat phytases is dependent on the phytate matrix and the phytase origin

BACKGROUND

Phytases increase utilization of phytate phosphorus in feed. Since wheat is rich in endogenous phytase activity it was examined whether wheat phytases could improve phytate degradation compared to microbial phytases. Moreover, it was investigated whether enzymatic degradation of phytate is influenced by the matrix surrounding it. Phytate degradation was defined as the decrease in the sum of InsP₆ + InsP₅.

RESULTS

Endogenous wheat phytase effectively degraded wheat Ins₆ + InsP₅ at pH 4 and pH 5, while this was not true for a recombinant wheat phytase or phytase extracted from wheat bran. Only microbial phytases were able to degrade InsP₆ + InsP₅ in the entire pH range from 3 to 5, which is relevant for feed applications. A microbial phytase was efficient towards InsP₆ + InsP₅ in different phytate samples, whereas the ability to degrade InsP₆ + InsP₅ in the different phytate samples ranged from 12% to 70% for the recombinant wheat phytase.

CONCLUSION

Wheat phytase appeared to have an interesting potential. However, the wheat phytases studied could not improve phytate degradation compared to microbial phytases. The ability to degrade phytate in different phytate samples varied greatly for some phytases, indicating that phytase efficacy may be affected by the phytate matrix.

Improvement of Aspergillus sulphureus endo-beta-1,4-xylanase expression in Pichia pastoris by codon optimization and analysis of the enzymic characterization

The gene xynB from Aspergillus sulphureus encoding the endo-beta-1,4-xylanase was de novo synthesized by splicing overlap extension polymerase chain reaction according to Pichia pastoris protein's codon bias. The synthetic DNA and wild-type DNA were placed under the control of a glyceraldehyde-3-phosphate dehydrogenase gene promoter (GAP) in the constitutive expression vector plasmid pGAPzalphaA and electrotransformed into the P. pastoris X-33 strain, respectively. The transformants screened by Zeocin were able to constitutively secrete the xylanase in YPD liquid medium. The maximum yield of the recombinant xylanase produced by the synthetic DNA was 105 U ml(-1), which was about 5-fold higher than that by wild-type DNA under the flask culture at 28 degrees Celsius for 3 days. The enzyme showed optimal activity at 50 degrees Celsius and pH 5.0. The residual activity remained above 90% after the recombinant xylanase was pretreated in Na(2)HPO(4)-citric acid buffer (pH 2.4) for 2 h. The xylanase activity was significantly improved by Zn(2+). These biochemical characteristics suggest that the recombinant xylanase has a prospective application in feed industry as an additive.

Effects of exogenous enzymes (phytase, non-starch polysaccharide enzyme) in diets on growth, feed utilization, nitrogen and phosphorus excretion of Japanese seabass, Lateolabrax japonicus

A feeding experiment was conducted to investigate the effects of exogenous enzymes (phytase, non-starch polysaccharide enzymes: WX and VP, supplied by DSM) on growth performance and excretion of Japanese seabass (Lateolabrax japonicus) (initial mass 6.26+/-0.10 g). A basal diet was used as a control that contained a mixed protein source, and lysine, methionine and valine were supplemented to simulate the essential amino acid pattern of fish meal. Four other diets were supplemented with 200 mg phytase (500 IU), 400 mg VP, 800 mg WX, or a combination of 800 mg WX and 400 mg VP per kg diet, respectively. Each diet was assigned to triplicate groups of fish in floating sea cages, and each cage was stocked with 60 fish. The results showed specific growth rate (SGR) and feed efficiency ratio (FER) were not significantly improved by the phytase supplementation. However, supplementations with WX and VP significantly enhanced the SGR and FER (P<0.05). Phosphorus retention was significantly increased by the supplementation with phytase, whereas nitrogen retention was also enhanced by supplementations of non-starch polysaccharide enzymes (P<0.05). The excretion experiment showed that the soluble phosphorus and ammonia nitrogen in starved fish were constant, irrespective of dietary treatments. The total phosphorus effluent in fish fed the diet with phytase supplementation was significantly lower compared with the control group after feeding to satiation (P<0.05), but soluble phosphorus excretion was still independent of dietary treatments. The ammonia excretion in satiated fish significantly decreased with supplementations of non-starch polysaccharide enzymes.

Performance of growing-finishing pigs fed diets based on normal or low viscosity rye fed with and without enzyme supplementation

One hundred and forty crossbred pigs (Pig Improvement Canada Ltd, Acme Alberta), weighing an average of 21.5 + 3.6 kg, were assigned on the basis of sex, weight and litter to one of five dietary treatments. The control diet was barley-based, while in the remaining four treatments, the grain component consisted of either normal or low viscosity rye fed with or without pentosanase. Digestibility coefficients for dry matter, crude protein and gross energy were significantly (P = 0.0001) higher for the rye-based diets than the barley based diet. There were no differences in digestibility coefficients between normal and low viscosity diets or between diets supplemented or unsupplemented with pentosanase. Over the entire experimental period (21.5 to 100.7 kg), pigs fed the normal viscosity rye gained better (P = 0.001) and had a higher daily intake (P = 0.001) than pigs fed the low viscosity rye. Pigs fed the low viscosity rye tended to gain slower than pigs fed barley and with lower intake while pigs fed the normal viscosity rye had similar gains and intake to the pigs fed barley. Enzyme supplementation failed to improve pig performance. Males had higher gains and intake than females (P < 0.05). Enzyme supplementation, rye viscosity or choice of cereal grain had no effect on any of the carcass traits measured. In conclusion, the results of the present experiment indicate that rye is a good alternative to barley for use in growing-finishing rations and becomes increasing attractive as the age of the pig increases. Breeding efforts directed towards reducing the viscosity of rye are unlikely to be successful in improving the nutritive value of rye for swine.