Effects of variety, the 1B/1R translocation and xylanase supplementation on nutritive value of wheat for broilers

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.

Meta-analysis of effect of a mono-component xylanase on the nutritional value of wheat supplemented with exogenous phytase for broiler chickens

A total of 1600 Ross broiler chicks were used in six separate balance studies (with equivalent protocols) to investigate the effect of an exogenous xylanase on the nutritional value of wheat (supplemented with a background of exogenous phytase) sourced from Asia, North America and Europe. The mean apparent metabolisable energy of the 10 batches of wheat per se was 13.4 MJ/kg DM and the addition of xylanase increased (P < 0.001) this by an average of 0.43 MJ/kg DM (~3.2%). Apparent ileal digestibility of nitrogen in the 10 batches of wheat per se was 69.8% and xylanase addition increased (P < 0.001) this by 2%. The apparent ileal disappearance of soluble and insoluble non-starch polysaccharides (NSP) was –53% and +5%, respectively and xylanase addition increased these by 28% and 15%, respectively. The apparent ileal disappearance of total arabinose + xylose was –10% and xylanase increased this by 21%. The apparent ileal flow of fucose was 0.38 g/kg DM intake and xylanase addition reduced (P < 0.05) this by 0.03 g/kg DM intake. There was a significant negative correlation between the apparent ileal flow of fucose and the digestibility of nitrogen and energy in the wheat and the wheat plus xylanase. These results demonstrate the continued effectiveness of exogenous xylanase to enhance the nutritional value of wheat for broiler chickens. Furthermore, the degradation of NSP fractions is confirmatory of both soluble and insoluble fibre hydrolysis in the intestine of the birds. Finally, although de-caging, viscosity amelioration and microbial changes are likely to be involved, the reduced flow of fucose in the intestine of birds fed wheat with supplemental xylanase is indicative of reduced endogenous (mucin) loss with net energy and enteric health implications. The effect of wheat pentosans and xylanase on intestinal secretion and endogenous protein and energy loss is an area for future study. Finally, the results presented herein suggest a reduction in soluble NSP concentrations in wheat over the past 2–3 decades, which is a trend that may explain anecdotal observations that the incidence of so-called sticky wheats is in decline. Systematic assessment of the implications of changing substrate concentrations and characteristics for new xylanase development is warranted.

Energy utilization and growth performance of chickens fed novel wheat inbred lines selected for different pentosan levels with and without xylanase supplementation

Different F5 recombinant inbred lines from the cross Yumai 34×Ukrainka were grown in replicated trials on a single site in one harvest year at Rothamsted Research. A total of 10 samples from those lines were harvested and used in a broiler experiment. Twenty nutritionally complete meal-form diets that had 630 g/kg of wheat with different amounts of pentosan, with and without exogenous xylanase supplementation, were used to compare broiler growth performance and determine apparent metabolizable energy corrected for N retention (AMEn). We examined the relationship between the nutritive value of the wheat samples and their chemical compositions and results of quality tests. The amounts of total and water soluble pentosans in wheat samples ranged from 36.7 to 48.0 g/kg DM, and 6.7 to 11.6 g/kg DM, respectively. The mean crude oil and protein contents of the wheat samples were 10.5 and 143.9 g/kg DM, respectively. The average determined value for the kinematic viscosity was 0.0018 mPa.s, and 2.1 mPa.s for the dynamic viscosity. The AMEn of the wheat-based diets had a maximum range of 0.47 MJ/kg DM within the ten wheat samples that were tested. Xylanase supplementation improved (P<0.05) dietary AMEn, dry matter, and fat digestibility coefficients. There was a positive (P<0.05) relationship between in vitro kinematic viscosity of the wheat samples and the total pentosan content. There was a negative relationship between the total pentosan content in the wheat and broiler growth performance. An increase by 10 g of pentosan per kg of wheat reduced (P<0.001) daily feed intake and weight gain by 2.9 g and 3.5 g, respectively. The study shows that the feeding quality of wheat samples can be predicted by their total pentosan content. Supplementary xylanase improved energy and nutrient availability of all wheat samples that was independent of differences in pentosan content.

The effect of variety and growing conditions on the chemical composition and nutritive value of wheat for broilers

The aim of this study was to examine the effect of variety and growing conditions of wheat on broiler performance and nutrient digestibility. One hundred and sixty-four wheat samples, collected from a wide range of different sources, locations, varieties and years, were analyzed for a range of chemical and physical parameters. Chemical and physical parameters measured included specific weight, thousand grain weight (TG), in vitro viscosity, gross energy, N, NDF, starch, total and soluble non-starch polysaccharides (NSP), lysine, threonine, amylose, hardness, rate of starch digestion and protein profiles. Ninety-four of the wheat samples were selected for inclusion in four bird trials. Birds were housed in individual wire metabolizm cages from 7 to 28 d and offered water and feed ad libitum. Dry matter intake (DMI), live weight gain (LWG) and gain:feed were determined weekly. A balance collection was carried out from 14 to 21 d for determination of apparent metabolizable energy (AME), ME:gain, DM retention, oil and NDF digestibility. At 28 d the birds were sacrificed, the contents of the jejunum removed for determination of in vivo viscosity and the contents of the ileum removed for determination of ileal DM, starch and protein digestibility. The wheat samples used in the study had wide-ranging chemical and physical parameters, leading to bird DMI, LWG, gain:feed, ME:GE, AME content and ileal starch and protein digestibility being significantly (p<0.05) affected by wheat sample. A high level of N fertilizer application to the English and NI wheat samples tended to benefit bird performance, with increases of up to 3.4, 7.2 and 3.8% in DMI, LWG and gain:feed, respectively. Fungicide application also appeared to have a positive effect on bird performance, with fungicide treated (+F) wheat increasing bird DMI, LWG and gain:feed by 6.6, 9.3 and 2.7%, over the non-fungicide treated (-F) wheats. An increase (p<0.1) of 9.3% in gain:feed was also observed at the low seed rate of 40 compared to 640 seeds/m². It was concluded that the type of wheat sample and environmental growing conditions significantly affects bird performance when fed wheat-based diets.

Chemical and physical predictors of the nutritive value of wheat in broiler diets

The aim of this study was to establish relationships between chemical and physical parameters of wheat with performance and digestibilities of feed components in broiler chickens fed on wheat-based diets. Ninety-four wheat samples were selected for inclusion in four bird trials. Birds were housed in individual wire metabolism cages from 7 to 28 d and offered water and feed ad libitum. Dry matter intake (DMI), liveweight gain (LWG) and gain:feed were measured weekly. A balance collection was carried out from 14 to 21 d for determination of apparent metabolizable energy (AME), ME:gain, dry matter retention, oil and neutral detergent fibre (NDF) digestibility. At 28 d the birds were humanely killed, the contents of the jejunum removed for determination of in vivo viscosity and the contents of the ileum removed for determination of ileal dry matter, starch and protein digestibility. When wheat parameters were correlated with bird performance data, it was found that specific weight was not significantly (p>0.05) related to bird performance. Bird DMI, LWG and gain:feed were best correlated (p<0.05) with the rate of starch digestion, although the coefficients of correlation (r) were still low (0.246 to 0.523). A negative relationship (p<0.01) between AME and total (r = −0.432) and soluble (r = −0.304) non starch polysaccharide (NSP) was observed in this study. Thousand grain weight (TG) was positively correlated with DMI (r = 0.299), LWG (r = 0.343) and gain:feed (r = 0.371). When establishing multiple regression relationships, correlation coefficients greater than 0.8 were achieved for DMI, LWG, gain:feed and ileal crude protein digestibility. However, the economics involved in determining the parameters involved in the regressions make the process impractical.

Comparison of gastrointestinal transit times between chickens from D+ and D- genetic lines selected for divergent digestion efficiency

D+ (high digestion efficiency) and D- (low digestion efficiency) genetic chicken lines selected for divergent digestion efficiency were compared in this experiment. Gizzard functions were tested in terms of digesta mean retention time and reactions to high dilution of a corn diet with 15% coarse sunflower hulls. The corn standard (S) and high fibre (F) experimental diets were given from 9 days of age to chickens from both lines. Besides the measurements of growth efficiencies (9 to 20 days), digestibilities (20 to 23 days) and gut anatomy (0, 9, 29, 42 and 63 days), two digestive transit studies were performed at 9 and 29 days of age. For the transit studies, the S and F diets were labelled with 0.5% TiO2 and 1% Cr-mordanted sunflower hulls. These diets were fed ad libitum during 3 days, and then the birds were euthanized. The digestive contents were analysed for the determination of marker concentrations and mean retention times (MRTs) in digestive compartments (crop + oesophagus, proventriculus + gizzard, duodenum + jejunum, ileum, rectum + cloaca and caeca) were determined. D+ birds were confirmed as better digesters than D- birds during the growth period, in association with larger gizzard and pancreas, and lighter small intestine in D+ than in D-birds. The MRT in the proventriculus-gizzard system, higher in D+ than in D- birds, was a major factor associated with differences between D+ and D- birds regarding digestion efficiencies and gut anatomy. Diet dilution with fibres reduced differences in digestion efficiencies and proventriculus-gizzard MRT between lines. Differences in gut anatomy between lines tended to disappear after 8 weeks of age. In conclusion, this study showed that MRT in the proventriculus-gizzard system was a major factor associated with genotype differences between the D+ and D- genetic chicken lines selected for divergent digestion efficiency, with longer MRT found in D+ than in D- birds.

Broiler performance and in vivo viscosity as influenced by a range of xylanases, varying in ability to effect wheat in vitro viscosity

1. Exogenous enzymes such as xylanase are used in diets for broilers to eliminate anti-nutritive effects caused by the presence of non-starch polysaccharides (NSP). It has been proposed that the mechanism by which xylanases exert their effect is through reducing in vivo viscosity within the broiler digestive tract. Previous research has reported that in vitro viscosity was a reasonable predictor of in vivo viscosity and that this method could be used to assess the efficacy of xylanases. 2. The objective of this study was to examine the response of broilers offered a wheat-based diet supplemented with a range of xylanases, varying in ability to reduce in vitro viscosity. 3. A total of 18 xylanases (Syngenta Animal Nutrition) were used to investigate the effect of xylanase on wheat in vitro viscosity. For the in vitro viscosity assay, pepsin was dissolved in either 005 or 01 M hydrochloric acid (HCl). 4. A wheat-based diet was formulated, produced and split into 7 batches; xylanase (500 U/kg) was sprayed onto 6 of the batches and the 7th was the control. This was repeated three times to produce a total of 21 diets, 18 of which contained xylanase. 5. The experiment was conducted in three consecutive trials. Each trial utilised 63 male, Ross broilers from 7 to 28 d of age. Dry matter intake (DMI), liveweight gain (LWG) and gain:feed were determined weekly. Excreta were collected from d 14 to 21 for determination of apparent metabolisable energy (AME). Oil and neutral detergent fibre (NDF) digestibility and ileal digestibility of dry matter (DM) and starch were determined. 6. Regression analyses were applied to the mean intestinal viscosity against DMI, LWG, gain:feed and the ratio of metabolisable energy to gross energy (ME:GE). To compare xylanases across the three trials, the data were subjected to REML analysis (Genstat 5). 7. When 01 M HCl was used for dissolution of pepsin, considerable reductions in in vitro viscosity were achieved for the majority of the xylanases-to values less than 12% of the control treatment. When 005 M HCl was used for the dissolution of pepsin, initial viscosity values were lower and the reduction in in vitro viscosity less dramatic than that observed with 01 M HCl. 8. With the exception of diets containing xylanases 9003 and 7162, significant reductions in in vivo viscosity were observed for diets containing xylanase in comparison to the control diet. 9. In terms of gain:feed, ME:GE and AME the xylanases ranked best were 2230 and 9003. Xylanase 2230 also resulted in the highest values for ileal DM and starch digestibility. 10. There were weak but significant relationships between in vitro viscosity and in vivo jenjunal digesta viscosity when in vitro viscosity was determined using either 01 or 005 M HCl (r(2)= 0287 and 0240, respectively). 11. The relationship between jejunal viscosity and DMI was significant (P < 005) but relatively poor (r(2)= 023). There were also significant (P < 005) relationships between jejunal digestal viscosity and gain:feed and ME:GE (r(2)= 034 and 028, respectively). 12. In conclusion, in vitro viscosity may be of some use in predicating xylanase response in vivo.

Effects of wheat variety and specific weight on dietary apparent metabolisable energy concentration and performance of broiler chicks

1. This study used 4 wheat cultivars (Brigadier, Chaucer, Consort, Reaper) from three locations (Crossnacreevy, C; Downpatrick, D; Limavady, L), which had given rise to differences in wheat specific weight (SW), to examine the relationships between apparent metabolisable energy (AME) concentration, broiler performance and wheat SW. 2. The diets contained (g/kg): wheat 744, casein 142, blended vegetable fat 50, dicalcium phosphate 22, potassium bicarbonate 10.8, sodium bicarbonate 7.5, arginine 5, methionine 2, binder 8, trace minerals/vitamins 7.2, titanium dioxide 1.5. The diets were heat-treated (80 degrees C for 2 min) prior to pelleting (3 mm die). 3. SW ranged from 63 to 77 kg/hectolitre (hl), averaging 66, 69 and 76 kg/hl at D, C and L, respectively. In vitro viscosity of the wheat samples ranged from 5.2 to 17.5 cps and thousand grain weight (TGW) from 33.4 to 47.3 g. Mean TGW was similar at C and D (38.7, 37.0 g) but higher at L (43.1 g). In vitro viscosity was similar at C and L (11.2, 10.2 cps) but somewhat higher at D (14.4 cps). Crude protein (6.25 N) ranged from 116 to 147 g/kg and tended to be higher at D. Starch, which ranged from 612 to 656 g/kg, was least at D (617 g/kg) and greatest at L (641 g/kg). 4. Crude protein, crude fibre and total non-starch polysaccharide (NSP) were negatively correlated with SW, the R2 being respectively 0.38 (P<0.05), 0.16 (NS) and 0.45 (P<0.05). TGW and starch concentration were positively correlated with SW (R2=0.70, 0.44, respectively). There was a weak (NS) negative relationship (R2=0.19) between in vitro viscosity and SW. For both TGW and in vitro viscosity, correlations improved when variety was taken into account (R2=0.95, 0.92, respectively). 5. There were no significant effects of variety on dry matter (DM) intake or live weight gain (LWG). Gain: food was significantly higher (P<0.05) for Consort than for the other three varieties and the metabolisable energy ratio (ME:GE) just failed to attain significance (P=0.062). Calculated wheat AME (MJ/kg DM) was significantly (P<0.05) higher for Consort than for the other three wheats. There was a good correlation (R2=0.49) for the total data set between gain:food and ME:GE. In vivo viscosity varied from 13.6 to 28.6 cps for individual treatments and was significantly affected by variety (P<0001). 6. Although there were no significant differences in DM intake or LWG due to site the values for L (SW 76) were 6 and 5% lower, respectively, than for D (SW 66). Gain:food was lower (P<0.05) for C (SW 69) than for D. ME:GE, wheat AME and ME:gain were not significantly different between sites. 7. There was a weak (R2=0.18) positive relationship between ME:GE and SW corresponding to a 2.5% increase in energy value for a 10 kg/hl increase in SW and no relationship between gain:food and SW. When variety was taken into the regression the slope was similar but R2 increased to 0.82. 8. ME:GE and wheat AME concentration were negatively correlated with wheat in vitro viscosity (R2=0.64, 0.55, respectively). 9. It was concluded that in vitro viscosity appears to provide a better basis than SW for prediction of the nutritive value of wheats of unknown variety. If the variety is known then SW could be used to predict energy value. However, the effect of quite a large change in SW (10 kg/hl) was relatively small.