Effect of enzymes of microbial origin on in vitro digestibilities of dry matter and crude protein in soybean meal

The effects of supplementation with cellulase, xylanase, pectinase, hemicellulase, glucanase, phytase and protease of microbial origin on digestibility of crude protein (CP) and dry matter (DM) of soybean meal in vitro were examined in the present study. Changes in viscosity during in vitro digestion were also examined as an index of carbohydrate digestibility. Hemicellulase and all enzyme combinations without protease showed significant improvement of CP digestibility. Cellulase, xylanase, phytase and glucanase tended to improve CP digestibility. Dry matter digestibility was improved significantly by pectinase and all enzyme combinations. Cellulase and phytase tended to improve DM digestibility. Crude protein and DM digestibilities were the highest when all the enzymes except protease were added. Protease, cellulase, pectinase, xylanase, glucanase and hemicellulase significantly reduced viscosity, while phytase had no effect on viscosity. Viscosity was increased unexpectedly when all the enzymes were added. These results strongly suggest that a combination of carbohydrases improves the CP and DM digestibility of soybean meal while protease inhibits the actions of these enzymes. The present study also suggests that viscosity is not always a good index of digestibility. Moreover, excluding the protease from commercial crude enzyme preparations may improve digestibility.     

Enzymes (beta-glucanase and arabinoxylanase) and/or sepiolite supplementation and the nutritive value of maize-barley-wheat based diets for broiler chickens

1. Two experiments were conducted to study the effects of crude enzyme preparations (beta-glucanase and arabinoxylanase) and/or 20 g/kg Sepiolite (Exal) on the performance and nutrient digestion of broiler chickens fed on maize-barley-wheat based diets. 2. In experiment 1, enzymes improved daily bodyweight gain (by 14%; P<0.001) and food:gain ratios (8%; P<0.001). Sepiolite improved bodyweight gain on the diets not supplemented simultaneously with enzymes (by 6% in 21-d-old chickens, P<0.05) but reduced it for enzymes-supplemeented diets. Changes in productive perfiormance with both additives were associated with changes in diet digestibility and nitrogen balance. 3. In experiment 2, enzyme supplementation reduced viscosity in jejunum and ileum and the mean retention time of digesta in the gut. Sepiolite inclusion significantly reduced the viscosity of jejunum digesta and modified the retention times of digesta in the gut, depending upon whether enzymes had been added. There was a decreased retention time without enzymes but an increase with enzyme supplementation. 4. Although different mechanisms are presumed for enzymes and sepiolite, both seem to counteract the negative effects of soluble, non-starch polysaccharides (NSP) in the diet by modifying jejunal viscosity and improving organic matter digestibility.     

Studies of viscosity as the probable factor involved in the improvement of certain barleys for chickens by enzyme supplementation

The hypothesis that the sticky droppings and the poor performance of chicks fed on low‐enzyme barleys are due to hemicelluloses and related substances in barley, which in solution in the alimentary tract give rise to a highly viscous state, was tested.

It is demonstrated that pectin significantly reduced chick performance and the droppings produced were very sticky. A pectin‐degrading enzyme quickly reduced the viscosity of a solution of pectin and significantly improved the performance of chicks.

The effect of feeding a bacterial enzyme preparation on the viscosity of water extracts of the contents of the small intestines of chickens that were fed on a low‐enzyme barley, was studied. It is shown that the viscosities were reduced by the “enzyme”. The viscosities of extracts from chickens that were fed on barley alone were lowered by enzyme preparations that were effective in increasing the performance of chickens.

Aqueous extracts of Australian barleys, steamed Irish barley and processed Irish barley were highly viscous, whereas similar extracts of raw Irish barleys had very low viscosities. The viscosities of the former barley extracts were markedly lowered by adding “effective” (i.e. those which improve chick performance) enzyme preparations to them.

The “enzymes” gave similar results with a solution of β‐glucan, and it is concluded that the enzyme responsible for lowering the viscosities was endo‐β‐glucanase.

A simple method for the determination of endo‐β‐glucanase activity is described. The activities of Irish barleys were high, but the activities of Australian barleys were very low. The enzyme was present in “effective” crude enzyme preparations.

It is concluded that the poor nutritional value of low‐enzyme barleys is related to the glucan and β‐glucan components of barley. Under the particular conditions the glucan/β‐glucan components give rise to fairly stable highly viscous conditions in the small intestine.     

Feed enzyme supplementation does not ameliorate foot pad dermatitis in broiler chickens fed on a corn-soyabean diet

1.?Foot Pad Dermatitis (FPD) can be a serious health, quality and welfare problem in poultry production, with a significant affect on the economics of production. The physico-chemical properties of (NSP) have been correlated with increases in excreta viscosity and adherence, and hence FPD in broiler chickens.

2.?Two broiler experiments were conducted to evaluate the effects of different dietary non-starch polisaccharide (NSP) applications to corn-soyabean based diets in replicated floor pens. In addition to live performance, the incidence and severity of FPD was scored and, in experiment 2, intestinal viscosity and ammonia volatilization were measured.

3.?Live performance did not vary with the different treatments in either experiment and the incidence and severity of FPD, and ammionia volatisation in experiment 2, were unaffected. However, birds reared on enzyme supplemented diets had lower (P? 4.?In this study with corn-soyabean meal based diets, dietary enzyme supplementation had no affect on the incidence and severity of FPD. The lack of an association between the excreta viscosity and FPD is attributed to the multifactorial etiology of this condition.     

Improvement of the nutritional value of rye by the partial hydrolysis of the viscous water‐soluble pentosans following water‐soaking or fungal enzyme treatment

1. Two nutritional experiments with young chicks and one in vitro trial were carried out to determine the effect of water‐soaking and enzyme supplementation on the nutritive value of rye grain, and to establish the mode by which the effects were brought about.

2. In experiment 1, enzyme treatment of rye (1–0 g Tv cellulase/kg rye) improved weight gains by 15% (P<0–05) and food:gain ratios by 14% (P<0–05) but did not affect food consumption (P>0–05). Corresponding improvements produced by water‐soaking were 7 (P>0–05), 16 (P<0–05) and 10% (F<0–05). In the second experiment, similar trends occurred but improvements were less pronounced.

3. The second experiment also demonstrated that both enzyme supplementation and water‐soaking reduced the viscosity of both the diet and excreta, and increased the retention of fat.

4. Water‐soaking and fungal enzyme treatment caused an increase in extractable water‐soluble pentosans which were of sufficient molecular mass (not monomers or oligomers) to be almost entirely precipitated by 80% ethanol. Sufficient hydrolysis of these polysaccharides had occurred by both enzyme and soaking treatments, but not by normal digestion by chickens, to lower viscosity. The results suggest that the viscosity of rye can be reduced slowly by endogenous enzymes present in rye (water‐soaking), rapidly by a fungal enzyme preparation and in the lower sections of the gastrointestinal tract by microbial enzymes.

5. Both water‐soaking and enzyme treatment greatly improved the nutritive value of rye by bringing about a reduction in the viscosities of the water‐soluble and highly viscous pentosans. The results also suggest that the production of monomers or oligomers was not necessary for the lowering of viscosity observed with the two treatments.     

Effect of soaking,germination, and enzyme treatment of whole barley on nutritional value and digestive tract parameters of broiler chickens

1. An experiment was carried out to determine the effect of soaking at 0°C, soaking at room temperature, germination, or enzyme treatment of whole barley on feeding value and digestive tract parameters of 2‐ to 4‐week old broiler chickens given diets with 700g/kg whole barley.

2. Soaking or germination decreased the soluble and total β‐glucan content (P<0.05) and, except for soaking at 0°C, the acid extract viscosity of the grain also decreased (P< 0.05). Germination and soaking in the presence of enzymes produced the lowest β‐glucan content and viscosity.

3. Except for soaking in cold water, the soaking, germination and enzyme treatments increased weight gain and decreased food: gain ratio (P< 0.05). Correspondingly, the digestibility of protein, fat, and ash, and the digestible energy content, increased (P< 0.05) after enzyme treatment or germination.

4. Chickens fed on enzyme‐treated or germinated barley diets had intestinal contents with a greater proportion of dry matter and lower viscosity than chickens fed on untreated barley (P< 0.05). Consequently, the cages and chickens were cleaner (P< 0.05) and the weight of digestive organs as proportion of live weight was lower.

5. Particle size analysis of excreta revealed that whole barley was efficiently ground by the gizzards of 16‐d‐old chickens, and very few whole kernels were found.     

Effects of a mono-component endo-xylanase supplementation on the nutritive value of wheat-based broiler diets

1. Two trials were conducted to evaluate the effects of a mono-component thermostable endo-1,4-β-xylanase derived from Thermomyces lanuginosus on the nutritive value of wheat-based broiler diets. In a 5-week growth trial, the efficacy of xylanase supplementation at 0, 100, 150, 200, 400 and 4000 FXU/kg diet was evaluated. A short-term balance trial was carried out according to a 4?×?2 factorial arrangement of treatments, involving 4 wheat cultivars and endo-xylanase at 0 or 200 FXU/kg.

2. In the growth trial, enzyme supplementation from 0 to 400 FXU/kg reduced feed intake and improved feed conversion linearly. Digesta viscosity was significantly reduced by all enzyme inclusion levels by 49·6–56·9%, in a quadratic manner.

3. In the balance trial, xylanase supplementation resulted in a significant improvement of protein, lipid and dry matter apparent digestibility coefficients of diets, accompanied by improved dietary AME _N values. There was a significant wheat?×?enzyme interaction on AME _N and lipid digestibility. There was a significant effect of wheat cultivar on dry matter digestibility.     

Effects of cultivar,pelleting and enzyme addition on nutritive value of barley in poultry diets

1. The effect of pelleting process and Trichoderma viride enzymes (TVE) addition on apparent metabolisable energy, corrected for nitrogen balance (AMEn) and on productive value of practical diets containing 40 and 45% of three different barley cultivars and one wheat were studied in poultry.

2. The effect of the pelleting process on AMEn was inconsistent and was dependent on the cereal included and the addition of enzyme.

3. The growth trial showed a significant effect of enzyme addition to pelleted diets over the whole growth period (0 to 42 d). Addition of TVE improved weight gain and food efficiency by 1.3% and 2.9%, respectively and decreased food intake by 1.6% between 0 and 22 d. In the finisher period (23 to 42 d) TVE improved efficiency by 2.8% and reduced food intake by 2.9%.

4. The incidence of sticky droppings was related to the viscosity of barley used, and enzyme supplementation reduced it. Both pelleting and enzyme addition increased dry matter content of excreta.

5. At the end of the experiment, 14 animals per treatment were slaughtered and carcass yield, viscera weight and abdominal fat were determined.     

Variation in levels of non-starch polysaccharides and endogenous endo-1,4-β-xylanases affects the nutritive value of wheat for poultry

1. Endo-1,4-β-xylanase is known to improve the nutritive value of wheat-based diets for poultry by degrading dietary arabinoxylans. However, broilers’ response to supplementation of wheat-based diets with exogenous endo-1,4-β-xylanase is not always observed.

2. In this study, 108 different wheat lots were analysed for levels of extract viscosity as well as for endogenous endo-1,4-β-xylanase activity, and the impact of these two variables in animal performance was tested.

3. Results revealed that endogenous endo-1,4-β-xylanase activity and extract viscosity content varied widely among different wheat lots. Thus, a trial was conducted to evaluate the efficacy of exogenous enzyme supplementation in broiler diets using wheats with different levels of extract viscosity and endogenous endo-1,4-β-xylanase activity.

4. The data revealed that exogenous enzyme supplementation was only effective when the wheat present in the diet had high levels of extract viscosity (14.8 cP) with low endogenous endo-1,4-β-xylanase activity (347.0 U/kg). Nevertheless, it is apparent that exogenous microbial xylanases reduce digesta extract viscosity and feed conversion ratio independently of the endogenous properties presented by different wheat lots.

5. The data suggest that extract viscosity and/or endogenous endo-1,4-β-xylanase activity affect the response to enzyme supplementation by poultry fed on wheat-based diets.     

Evaluation of Dairy–Yeast Prebiotic Supplementation in the Diet of Juvenile Goldfish in the Presence or Absence of Phytoplankton and Zooplankton

Abstract

Prebiotics recently have been shown to increase immune responses and disease resistance in certain fish species; therefore, the current study was conducted to evaluate the commercially available dairy–yeast prebiotic, GroBiotic-A, for use with juvenile goldfish Carassius auratus. The study consisted of two 10-week feeding trials in which juvenile goldfish were fed practical diets that were either unsupplemented or supplemented with the dairy–yeast prebiotic at 2% by dry weight. Juvenile fish were sorted by size and stocked into 12 units within each of two culture systems: one indoor system supplied with recirculated well water and one system located outdoors with a continuous flow of pond water to provide a source of phytoplankton and zooplankton. Both diets were fed to fish in six units within each system at the same fixed percentage of body weight twice daily. Culture system (i.e., presence or absence of phytoplankton and zooplankton) was the primary factor influencing (P < 0.0001) percent weight gain, feed efficiency, and survival of goldfish during the feeding trials. No dietary effect was detected, although there was a significant (P < 0.05) interaction between culture system and diet, with supplementation of the dairy–yeast prebiotic tending to improve weight gain and feed efficiency of fish in the presence of phytoplankton/zooplankton. During a controlled disease challenge with an intraperitoneally administered dose of Aeromonas hydrophila that was equivalent to a predetermined LD50 (dose lethal to 50% of test fish), average survival values ranged between 67% and 83% for fish that previously had access to phytoplankton/zooplankton compared with 17–33% for fish that had no access to phytoplankton/zooplankton. The dairy–yeast prebiotic, however, did not enhance resistance of goldfish to the bacterial pathogen and did not greatly alter microbiota of the anterior or posterior gastrointestinal tract based on denaturing gradient gel electrophoresis analysis. In conclusion, the dairy–yeast prebiotic did not improve feed efficiency in goldfish or resistance to a bacterial pathogen as previously observed in golden shiners Notemigonus crysoleucas and hybrid bass (white bass Morone chrysops × striped bass M. saxatilis).     

Blood chemistry for the diagnosis of hepatobiliary disease in birds. A review

Summary

A review is presented of current knowledge with regard to blood chemistry for the diagnosis of hepatobiliary disease in birds. Straightforward conclusions are difficult, because research on this subject has been limited.

Jaundice caused by hyperbilirubinaemia occurs infrequently in birds, because the main bile pigment is biliverdin and not bilirubin. A yellow discolouration of avian plasma is often caused by the presence of carotenoids. The diagnostic value of plasma ALAT concentrations is controversial. Although ASAT and LD are not specific for the liver they appear to be sensitive enzymes to detect liver cell damage.

GLDH is liver specific in a number of animal species (including birds) and might prove to be a useful enzyme for diagnostic purposes. AP and GGT seem less useful. Little information is available on the diagnostic value of plasma bile acids and plasma dye clearance tests.     

Effects of oregano essential oil with or without feed enzymes on growth performance,digestive enzyme,nutrient digestibility,lipid metabolism and immune response of broilers fed on wheat–soybean meal diets

1.?The study was conducted to determine the effects of dietary supplementation of enzyme and oregano essential oil at two levels, alone or together, on performance, digestive enzyme, nutrient digestibility, lipid metabolism and immune response of broilers fed on wheat–soybean meal based diets.

2.?The following dietary treatments were used from d 0 to 21. Diet 1 (control, CONT): a commercial diet containing no enzyme or oregano essential oil, diet 2 (ENZY): supplemented with enzyme, diet 3 (EO250): supplemented with essential oil at 250 mg/kg feed, diet 4 (EO500): supplemented with essential oil at 500 mg/kg feed, diet 5 (ENZY + EO250): supplemented with enzyme and essential oil at 250 mg/kg, and diet 6 (ENZY + EO500): supplemented with enzyme and essential oil at 500 mg/kg.

3.?Birds fed on diets containing ENZY, EO250 and ENZY + EO250 had significantly higher weight gain than those given CONT diet from d 0 to 7. No significant effects on feed intake, feed conversion ratio, mortality, organ weights except for jejunum weight and intestinal lengths was found with either enzyme or essential oil, alone or in combination, over the 21-d growth period. The supplementation of essential oil together with enzyme decreased jejunum weight compared with essential oil alone.

4.?Supplementation with enzyme significantly decreased viscosity and increased dry matter of digesta, but did not alter pH of digesta. There was no effect of essential oil alone at either concentration on viscosity, dry matter or pH of digesta. A significant decrease in viscosity of digesta appeared when essential oil was used with together enzyme.

5.?The supplementation of essential oil at both levels with or without enzyme significantly increased chymotrypsin activity in the digestive system, and improved crude protein digestibility.

6.?The higher concentration of essential oil with and without enzyme significantly increased serum total cholesterol concentrations. No significant effect on immune response was found with either enzyme or essential oil, alone or together.

7.?Enzymes and essential oil had different modes of actions. The supplementation of enzyme with essential oil in diets is likely more effective in view of performance, nutrient digestibility, enzyme activities and immune system.     

The effect of graded inclusions of waxy starch hull-less barley and a multi-component exogenous carbohydrase on the growth performance,nutrient digestibility and intestinal morphometry of broiler chickens

ABSTRACT

1. A 21-d experiment was conducted to investigate the effect of graded inclusions of waxy starch hull-less (WSHL) barley and a multi-component exogenous carbohydrase on the growth performance, nutrient digestibility and intestinal morphometry of broiler chickens. Five levels of WSHL barley inclusion (0, 65, 130, 195 and 260 g/kg) in a wheat-based diet, and two levels of enzyme supplementation (0 and 150 g/tonne of feed) were evaluated in a 5 × 2 factorial arrangement of 10 dietary treatments. All diets were equivalent in metabolisable energy and digestible amino acid content. A total of 400, one-d-old male broilers (five cages/treatment; eight birds/cage) were used in the experiment.

2. Regardless of enzyme supplementation, feed intake declined (P < 0.001) with increasing inclusion of WSHL barley. Increasing levels of WSHL barley (P < 0.001) and supplemental enzyme (P < 0.01) increased gain to feed ratio.

3. Birds fed diets with 0 g/kg WSHL barley showed the lowest (P < 0.001 to 0.01) digestibility for all nutrients except starch. Only starch digestibility was improved (P < 0.05) by enzyme supplementation. The nitrogen-corrected apparent metabolisable energy improved with increasing inclusion of WSHL barley (P < 0.001) and supplemental enzyme (P < 0.001). Increasing inclusion of WSHL barley increased the relative weight of gizzard (P < 0.001) and reduced jejunal digesta viscosity (P < 0.01). Supplemental enzyme (P < 0.001) reduced digesta viscosity.

4. All levels of WSHL barley inclusion improved digestibility of dry matter, nitrogen and fat, whilst energy utilisation improved at inclusions of 130 g/kg WSHL and above, probably due to lowered digesta viscosity and better development of the gizzard. Gain to feed ratio, starch digestibility, energy utilisation and jejunal digesta viscosity can benefit from carbohydrase supplementation in wheat-based diets, regardless of barley inclusion level.     

Effects of pea extrusion and enzyme and probiotic supplementation on performance,microbiota activity and biofilm formation in the broiler gastrointestinal tract

ABSTRACT

1. The effects of supplementation of broiler chicken diets with pea meal, carbohydrase enzymes and a probiotic were investigated for potential performance improvement.

2. Raw or extruded pea meal (cv Model, grown in Poland) was included in a wheat-soybean meal-based diet at 250 g/kg. The diets were unsupplemented (control) or supplemented with either carbohydrase enzymes (200 U/kg xylanase and 10 U/kg β-glucanase in feed) or a probiotic (Bacillus subtilis), or both. The diets were fed to Ross 308 broilers aged 9–28 days.

3. After two additional days, chick gastrointestinal tracts were excised and analysed for the presence of Bacillus subtilis biofilm; and the ileal and caecal digesta were analysed for bacterial enzyme activities and to determine the concentration of short-chain fatty acids (SCFAs).

4. Feeding the pea-based diet supplemented with the probiotic compromised feed utilisation, due to higher feed intake. The addition of enzymes to the raw, but not the extruded, pea containing diet partially ameliorated this effect (pea form × additives; P < 0.002).

5. In the ileal digesta, interactions between the dietary treatments were observed for the activities of all bacterial glycolytic enzymes and for SCFA concentrations. β-glucosidase, α-galactosidase and β-glucuronidase were highest in birds fed the diet containing extruded pea supplemented with the probiotic and enzymes (pea form x additives; P = 0.018 to P < 0.006). In the caecal digesta, interactions were observed for bacterial enzyme activities, but not for total SCFA concentration. Biofilm formation in the caecum indicated that the probiotic strain was metabolically active in the broiler gut.

6. In conclusion, supplementation of diets containing raw or extruded pea meal with enzymes and a Bacillus subtilis spore-based probiotic modulated microbiota activity but had no clear effects on broiler performance. Probiotic administration did not cause excessive fermentation in the ileum and caecum but enhanced Bacillus subtilis spp. biofilm formation in the caecum, which may be indicative of a beneficial effect on gut health.     

Measurement of certain plasma and serum enzymes in the horse

The study of the use of serum or plasma enzymes in the horse is reviewed.

Analyses of such enzymes in the horse have been performed mainly for the detection and monitoring of abnormalities which affect liver tissue and muscle fibres. Examples of muscle disorders are post-anaesthetic forelimb lameness and the clinical myopathy syndrome which varies from a mild “tying-up” to a severe paralytic myoglobinuria (EPM). Measurements have also been made during training periods in an endeavour to assess the effects of exercise on muscle tissue. One of the benefits of such a study could be the prediction of the period of optimum performance.

The two enzymes most frequently used for. muscle studies have been glutamic oxaloacetic transaminase (GOT) (aspartate aminotransferase) and creatine Phosphokinase (CPK). The former, while not muscle specific and less sensitive than CPK to small amounts of muscle tissue damage, has a slower clearance rate from blood than CPK. Determination of both enzymes together has some advantages in determining the prognosis in cases with severe muscle damage. Later studies have included aldolase, which is a sensitive skeletal muscle specific enzyme and lactic dehydrogenase (LDH), which is widely distributed by various tissues at high concentrations. Most of the work on serum LDH has centred on its separation into 5 isoenzymes, and on relating the isoenzyme pattern to the various tissues. More studies on this, and on the isoenzymes of CPK, are required.

Apart from cost, one of the major problems in enzymology has been lack of a standardisation of laboratory methods which has led to a wide range of published normal values. Reliance on such values may lead to difficulties in interpretation, particularly when serum changes are small.     

Influence of inclusion level of barley in wheat-based diets and supplementation of carbohydrase on growth performance,nutrient utilisation and gut morphometry in broiler starters

ABSTRACT

1. The influence of barley inclusion level and supplementation of a multi-component non-starch polysaccharide degrading enzyme on performance and nutrient utilisation in broilers was investigated. Normal-starch hulled barley was evaluated with five levels of inclusion (0, 141, 283, 424 and 565 g/kg) in a wheat-based diet and two levels of enzyme supplementation (0 and 150 g/tonne of feed; a 5 × 2 factorial arrangement of 10 dietary treatments). All diets were equivalent in metabolisable energy and digestible amino acid contents. A total of 400, one-d old male broilers (five cages/treatment; eight birds/cage) were used in the experiment.

2. Regardless of enzyme supplementation, weight gain (WG) increased up to 283 g/kg of barley and was reduced afterwards (P < 0.01). Increasing levels of barley resulted in greater (P < 0.001) gain per feed (G/F). Enzyme addition increased WG (P < 0.05) and G/F (P < 0.001) at each barley inclusion level.

3. Birds fed diets with 0 and 565 g/kg barley showed the lowest and highest (P < 0.001to 0.05) digestibility for all nutrients measured, respectively. Digestibility of all nutrients was improved by enzyme supplementation at each barley inclusion level (P < 0.05). The nitrogen-corrected apparent metabolisable energy improved with increasing inclusion of barley (P < 0.001) and supplemental enzyme (P < 0.01). Increasing inclusion of barley increased the relative weight of gizzard (P < 0.001) and reduced jejunal digesta viscosity (P < 0.001). Supplemental enzyme (P < 0.001) reduced digesta viscosity.

4. The optimum inclusion level of barley, with respect to growth performance, was 283 g/kg of diet. Increasing barley inclusion improved nutrient and energy utilisation, possibly through lowered digesta viscosity and better function of the gizzard. Feed efficiency and nutrient and energy utilisation can benefit from carbohydrase supplementation in barley-based diets, regardless of barley inclusion level.     

Effects of enzyme supplementation on the nutritive value of dehulled lupins

1. Separate balance experiments were conducted to assess the potential of 2 commercial enzyme supplements to improve the nutritive value of dehulled lupin kernels. One supplement (enzyme A) contained primarily xylanase, pen‐tosanase, hemicellulase activities and the other (enzyme B) primarily ß‐glucanase, hemicellulase and pectinase activities.

2. The enzymes were added at 0, 025, 0.50, 0.75 and 1.00 g/kg in diets containing (g/kg) lupins 300, sorghum 543, casein 91, celite (as marker) 20, and vitamins and minerals 46. Control diets, with and without enzyme supplementation contained sorghum and casein at 800 and 134 g/kg, respectively, and no lupins.

3. Growth rates and food conversion ratios (FCR) of birds over 7 days were not affected by lupin inclusion or enzyme supplementation. FCR of broilers fed on the sorghum diet was improved by enzyme A but not by enzyme B.

4. Heal starch digestibilities were slightly lower in birds fed on the lupin control diet (no enzyme) compared to the basal control diet.

5. Enzyme A increased the AME of the lupins from 10.01 MJ/kg DM to 11.65 MJ/kg DM when added at 0.5 g/kg. Higher rates of supplementation did not lead to further increases in AME values.

6. Enzyme A did not improve starch digestion in the diets but insoluble non‐starch polysaccharides concentration in the digesta decreased (50–41–42–71 g/g acid insoluble ash marker) with increasing enzyme supplementation, suggesting that the improvement in AME was the result of increased fermentation of fibre in the hindgut.

7. Enzyme B did not affect the AME of lupins nor the ileal digestibility of nutrients, but caused an increase in the concentrations of soluble non‐starch polysaccharides in the ileal digesta of chickens (19.21.35.77 mg/ml). This was accompanied by an increase in ileal digesta viscosity (11.4.34.2 m.Pa/s).     

Increased small intestinal fermentation is partly responsible for the anti‐nutritive activity of non‐starch polysaccharides in chickens

1. The mechanism of the anti‐nutritive activities of soluble non‐starch polysaccharides (NSPs) in broiler diets was investigated with emphasis on the inter‐relationship between viscosity and fermentation along the gut. Isolated soluble NSP were added to a control diet to effect high gut viscosity, and in vivo depolymerisation of the NSP was achieved using a commercial glycanase.

2. Addition of soluble NSPs significantly (P<0.01) increased gut viscosity, reduced the AME of the diet and depressed the growth and FCE of the birds. Enzyme supplementation of the NSP‐enriched diet reversed the adverse effects, increasing (P< 0.01) weight gain, FCE and AME. Comparisons of the viscosities (mPa) in birds fed on the NSP‐enriched diet and the same diet supplemented with enzyme were respectively: 11–9 v. 2–3 in the duodenum; 78–3 v. 4–4 in the jejunum and 409–3 v. 10–8 in the ileum.

3. Caecal volatile fatty acid concentration was markedly (P<0.01) elevated by enzyme supplementation, whereas ileal fermentation was inhibited.

4. Microscopic examination revealed that, among birds fed on the NSP‐enriched diet, there had been extensive small intestinal fermentation, which was eliminated by the enzyme supplementation.

5. Addition of a synthetic antibiotic (Amoxil) had no beneficial effects.

6. The current study demonstrated that increased fermentation occurs in the small intestine when a large amount of viscous NSPs is present in the diet and this is detrimental to the performance and well‐being of poultry.     

Fibre degrading enzymes and Lactobacillus plantarum influence liquid feed characteristics and the solubility of fibre components and dry matter in vitro

The effect of fibre degrading enzymes in combination with Lactobacillus plantarum on feed viscosity and pH and on solubilisation of non-starch polysaccharides (NSP) was studied in vitro using diets composed of cereals and soybean meal. The diet was incubated over time up to 24 h as liquid feed or liquid feed added L. plantarum and in addition both feeds were treated without or with fibre degrading enzymes.

Spontaneous fermentation developed in the liquid feed without L. plantarum and became noticeable after a period of 6 to 8 h, when pH began to drop. From 8 to 24 h there was a slow but steady reduction in pH down to a level of about pH 4.3. This development was irrespective of enzyme supplementation level. The L. plantarum treatment had already reached a pH of 4.2 after 8 h and a pH of 3.6 after 24 h.

The viscosity was reduced with supplementation with a high enzyme dose (6000 FXU and 600 FBG per kg diet), compared to the control diet (without enzymes). Treatment with L. plantarum (1.8 × 1011 CFU/kg feed) increased the viscosity over time, even with enzyme supplementation, compared to the control treatment.

Diets without and with enzyme supplementation and pre-treated as dry feed (control), liquid feed (incubated for 8 h) or liquid feed fermented with L. plantarum (incubated for 24 h), were subjected to an in vitro digestion procedure. Both pre-treatment as liquid feed and enzyme supplementation lead to a reduction in dry matter and in the insoluble NSP fraction during digestion in comparison with the control based on the original dry feed.

It may be concluded that enzyme supplementation to liquid or fermented feed may cause a reduction in the insoluble dietary fibre content as well as a reduction in feed viscosity, while the pH is not influenced.