Apparent Metabolizable Energy Content Research Articles

Effects of varying vicine, convicine and tannin contents of faba bean seeds ( Vicia faba L.) on nutritional values for broiler chicken

Faba bean tannins are known to decrease apparent protein digestibility. The vicine and convicine contained in the seeds reduce egg size in laying hens, but their effects in broiler chickens have never been reported. Vicia faba genotypes have been identified which result in a major reduction of these compounds in seeds. Tannins are located in seed hulls whereas vicine and convicine (VC) are located in the cotyledons and therefore they can be separated and re-combined in reconstituted faba beans (RFB) by mixing hulls and cotyledons from genotypes with variable tannin and VC contents, in order to evaluate their effects alone or in interaction. Six RFB were built with high, medium or low tannin contents (means of 9.9, 5.8 and 1.3 g/kg, respectively) combined with high or low VC contents (means of 10.1 and 0.7 g/kg, respectively). The six RFB were incorporated in the experimental diets and fed to broiler chickens in a balance experiment to measure apparent protein digestibility and apparent metabolisable energy (AMEn) content. The AMEn was lower for the high- than for the low-tannin RFB (12.08 MJ/kg versus 12.48 MJ/kg DM; P < 0.001). Also, the AMEn was lower for the high- than for the low-VC RFB (11.99 MJ/kg versus 12.34 MJ/kg DM; P < 0.05). The negative effects of the two anti-nutritional factors on energy were additive and a linear regression on their contents explains 80% of the variability. The total tract apparent protein digestibility was lower for the high- than for the low-tannin RFB (0.75 versus 0.86; P <0.001) with no significant interaction with VC contents, which in contrast have no significant effect on this trait. The results confirm the nutritional advantages of faba bean varieties free of tannins and low in vicine and convicine content in diets for poultry.

Lack of relationship between either specific weight or presence of the 1B1R gene and nutritive value of wheat in broiler diets

1. A study of the relationship between specific weight (SW) and nutritive value of wheat in diets offered to broilers up to 4 weeks of age was carried out using 10 varieties of wheat grown at three different locations; this gave rise to a range of specific weights from 59 to 76 kg/hl. 2. Because five varieties contained the 1B1R translocation and 5 did not, this allowed the effects of 1B1R on the performance of birds given high concentrations of dietary wheat to be further investigated. 3. The diets, which contained wheat at 744 g/kg with casein (142 g/kg) as the sole protein supplement, were heat-treated and pelleted. They were fed ad libitum to male, Ross broiler chicks from 7 to 28 d, in individual cages in a controlled environment room. 4. A 7 d excreta collection was made from 14 to 21 d for determination of apparent metabolisable energy (AME) content and wheat AME was calculated from the diet values. A separate determination of true metabolisable energy (TME) was undertaken using the method of McNab and Blair (British Poultry Science, 29: 697-707, 1988). 5. Wheat samples were analysed for proximate constituents, starch, total and soluble non-starch polysaccharides (NSP), amino acid content and gross energy and specific weight, thousand grain weight and in vitro viscosity were recorded. They were also subjected to near infrared reflectance spectroscopy (NIRS) with a view to establishing relationships with chemical constituents and performance parameters. 6. At 28 d the birds were humanely killed and in vivo viscosity was determined on the jejunal digesta supernatant. 7. There was quite a narrow range of crude protein content (N x 5.83) across the 30 wheat samples, the means for the three locations (Crossnacreevy, Downpatrick and Limavady, respectively) being 112, 121 and 122 g/kg. Starch contents of individual samples ranged from 604 to 679 g/kg, total NSP from 92.1 to 122.6 g/kg, soluble NSP from 17.6 to 32.6 g/kg and in vitro viscosity from 10.6 to 26.3 cps. 8. There were no significant varietal effects for dry matter intake (DMI), live weight gain (LWG) or gain:feed ratio. Apparent metabolisability of energy (ME:GE) for the diets ranged from 0.738 (Hussar) to 0.778 (Harrier) the effect being significant (P 0.05). TME values ranged from 16.3 to 16.6 MJ/kg DM (NS). 9. In vivo viscosity ranged from 12.3 (Ritmo) to 23.7 cps (Hussar), the varietal effects being significant (P < 0.001). Viscosity was significantly higher for the 1B1R varieties than for the non-1B1R (22.7 vs 16.3 cps) but there were no significant effects on mean DM intake, LWG, gain:feed, ME:GE, calculated wheat AME, ME:gain (MJ AME per kg gain) or TME. 10. Wheat AME was negatively correlated (P < 0.05) with total NSP (slope -0.035) but was significantly affected by variety, constants ranging from 16.74 to 17.79. For wheat TME there were significant variety*total NSP interactions with slopes ranging from 0.29 to -0.07. There was no significant relationship between wheat AME and soluble NSP and there were significant variety*soluble NSP interactions for TME with slopes ranging from 0.09 to -0.14. 11. Despite the relatively wide range of in vitro viscosity there was no significant correlation of either calculated wheat AME or wheat TME with in vitro viscosity. For TME there were significant variety*viscosity interactions with slopes ranging from 0.21 to -0.13 (P < 0.001). There was also no significant correlation between soluble NSP and in vivo viscosity. 12. AME values for the NIRS calibration set varied from 13.7 to 15.6 MJ/kg and averaged 14.6 MJ/kg, whereas for the validation set, the values ranged from 14.0 to 16.1 MJ/kg with the mean value being 14.7 MJ/kg. The best correlation coefficient (r(2)) of 0.90 was obtained when the calibration sample set was subjected to SMLR using the second-order derivatised data. However, moving to validation, the outcome was extremely poor with 1-VR values being 0.12 and 0.09, respectively, for the external validation and an internal validation subset. 13. In summary, none of the production characteristics showed a good correlation with specific weight. Using the linear estimates for wheat AME and TME the effect of a 10 kg/hl change in SW equates to a 3 or 1.4% change, respectively. The estimate for AME is likely to be a worst-case value due to the high inclusion level of wheat. The range of calculated wheat AME (approximately 1 MJ) across the 30 wheat samples is similar to that seen in previous studies for wheat grown in Northern Ireland and much lower than in some other studies. 14. None of the other parameters examined gave any better relationship with nutritive value (assessed as AME or TME) than SW. This is a disappointing outcome, particularly in view of some previous studies which suggested that in vitro viscosity provides a good prediction of nutritive value.

Effect of Wheat Cultivar and Enzyme Addition to Broiler Chicken Diets on Nutrient Digestibility, Performance, and Apparent Metabolizable Energy Content

A total of 5,000 one-day-old male broiler chickens were assigned to 8 different treatments in a 4 x 2 factorial design. Four wheat cultivars (Amiro, Guadalupe, Isengrain, and Horzal) and 2 levels (0 or 1 kg/t of feed) of an enzyme cocktail (Avizyme 1300, xylanase, 2,500 U/kg and protease, 800 U/kg) were used. Nutritionally complete mash diets contained 65 and 70% of the test wheat for the starter and grower period, respectively. Test wheats were used in diets for broilers, and growth performance and AME contents were measured. Broiler performance was measured in 4,800 broilers allocated to floor pens with 75 birds each and fed from 1 to 42 d of age. Digestibilities and AME contents of diets were measured in 200 broilers from 6 to 27 d of age individually allocated to battery cages. Chromic oxide (Cr(2)O(3)) at an inclusion rate of 0.5% in the diet was used as an indigestible marker. Apparent metabolizable energy was corrected by zero N balance to obtain AME(n). Wheat cultivar strongly influenced animal performance during the starter period (1 to 21 d of age). During the grower period (21 to 42 d of age), only BW and daily feed intake were influenced by wheat cultivar. Differences in daily feed intake were associated with differences in AME(n) intake during the starter period, but not during the grower period. Nutrient digestibility was higher with the use of enzyme. Animal performance was not affected (i.e., wheat cultivar differences were not eliminated by using enzymes). During the grower period, significant interactions were detected with regard to nutrient digestibility and AME(n). Differences in AME(n) content of wheat could not be explained by digestible starch.

Effects of different feed additives alone or in combination on broiler performance, gut microflora and ileal histology

1. The objectives of this experiment were to investigate the effects of different xylanases, alone or in combination with different organic acid and oligosaccharide sources, on bird performance, gut microflora and ileal histology. 2. Birds were given a diet based on a commercial formulation, which was split into 8 batches. Batch 1 contained the antibiotic growth promoter Avilamycin and acted as the positive control. To batch 2 the enzyme Allzyme PT® was added and to batch 3 Allzyme PT was added with the organic acid and oligosaccharide mixture Avimos®. To batch 4, Allzyme PT was added with the oligosaccharide mixture Biomos®. To batch 5, yeast extract 2012 was added with the organic acid mixture Gustor and the enzyme xylanase XP20. To batch 6, yeast extract 2012 and feed acidifier Gustor were added as before, with the enzyme Avizyme 1300. Batches 7 and 8 both acted as negative experimental controls, with no added growth promoters. 3. A total of 64 birds were housed in individual wire cages in each of three consecutive experimental replicates (24 birds/treatment). Birds were fed ad libitum from 7 to 28 d and a 7–d excreta collection was carried out to determine apparent metabolisable energy (AME) content. 4. At 28 d, the birds were killed and viscosity of jejunal digesta supernatant and gizzard weight were determined. Samples were taken from the crop, ileum and caecum and analysed for viable presumptive lactic acid bacteria and coliforms. The overall microbial flora was determined using denaturing gradient gel electrophoresis of 16S ribosomal DNA followed by DNA sequence analysis in order to assign amplicons to a bacterial species. Ileal sections were also collected for histological analysis. 5. Total live weight gain (12%) and gain : feed (9%) were significantly improved for all diets containing additives, compared to the negative control diets. All diets containing xylanases gave significantly lower in vivo viscosity values than the positive and negative controls. Diet treatment significantly affected viable coliform numbers in the ileum and also viable lactobacilli in the ileum and caecum. A substantial proportion of the bacteria present in the GI tract (40%) belong to unknown species. No effects of diet treatment on histological measurements were observed in this study. 6. All the additive combinations studied were at least as effective as the antibiotic growth promoter and the results for Allzyme PT® suggest that xylanase alone is as effective as any of the combinations studied.

A comparison of the effects of different yeast products and antibiotic on broiler performance

1. The objectives of this experiment were to compare the effects of different yeast products, with different nucleotide contents and inclusion rates, on broiler performance and to compare the effects to those observed with an antibiotic growth promoter. 2. Two experiments were carried out over two time replicates, one in individual wire cages and one in group pens. 3. Birds were given a diet based on a commercial formulation, which was split into 7 batches. One batch (C) contained no growth promoter and acted as a negative control, another (AV) contained the antibiotic growth promoter Avilomycin (5 g/tonne) and acted as the positive control. The other batches contained yeast extract 2012 at 100 g/tonne (Y21), yeast extract 2012 at 500 g/tonne (Y25), standard yeast 18 at 100 g/tonne (Y81), standard yeast 18 enriched in nucleotides at 100 g/tonne (Y8N1) and standard yeast 18 enriched in nucleotides at 500 g/tonne (Y8N5). 4. In the penned experiment, 280 Cobb broiler chicks (40 birds/treatment) were randomised to diet and pen position on day of hatch. Birds were fed ad libitum until slaughter at 28 d. Bird performance was monitored during the experimental period. 5. In the individual cage experiment, 63 Cobb broiler chicks (9 birds/treatment) were taken from the pens at 7 d of age and randomised to diet and cage position. Birds were fed ad libitum from d 7 to d 28. A 7-d excreta collection was carried out to determine apparent metabolisable energy (AME) content and nutrient digestibility between d 14 and d 21. Bird intake and weight were monitored weekly during the experimental period. At 28 d the birds were killed and viscosity of jejunal digesta supernatant was determined. 6. In the penned experiment, diet had no significant effect on dry matter intake (DMI), live weight gain (LWG) or gain:feed values during any individual week of the experiment or for the entire experimental period. In the caged experiment, DMI was numerically highest for birds fed Y25 diet over the entire experimental period, however, this only reached significance in the second week. LWG, gain:feed, viscosity of jejunal contents and gizzard weight were not significantly affected by dietary treatment. 7. Diet AV had a significantly higher AME content than diets Y25, Y81, Y8N1 or Y8N5. Also, oil and neutral detergent fibre (NDF) digestibility coefficients were significantly affected by diet treatment.

Sunflower seed meal as a substitute for soybean meal in commercial broiler chicken diets

1. An experiment was conducted to study the possibility of replacing soybean meal (SBM) with sunflower seed meal (SFM) in broiler chick diets. The SBM in broiler starter (317·9 g/kg) and finisher (275·4 g/kg) diets was replaced with SFM at 33, 67 and 100% on an iso-caloric and iso-nitrogenous basis using sunflower oil to balance the energy content of the diets. The metabolisable energy levels used in the diet were considerably less than the recommended levels for broilers. Each experimental diet was fed ad libitum from 2 to 42 d of age to 8 replicates of 5 birds. Parameters studied included amino acid and apparent metabolisable energy contents in food ingredients, body weight, food intake, food efficiency, leg abnormality score, dry matter digestibility, carcase traits, relative weight and length of intestine, fat and protein content in liver and serum biochemical profile. 2. SFM had higher concentrations of calcium, phosphorus, methionine and cystine and lower energy content than SBM. 3. Replacement of SBM with SFM up to 67% in starter and 100% in finisher diets did not affect weight gain. Total and 67% replacement of SBM with SFM depressed food efficiency at 21 and 42 d of age, respectively. Food intake was significantly higher in SFM-based diets than in the SBM reference diet at 21 and 42 d of age, except in groups given SFM100 at 21 d of age. In the latter group, the food intake was similar to that on the SBM reference diet. The digestibility of dry matter decreased with increased levels of SFM in the diet. 4. The relative weights of giblet, liver and abdominal fat, length of intestine, activity of alkaline phosphatase, concentrations of calcium and inorganic phosphorus in serum were not influenced by incorporation of SFM in the broiler diet. 5. The ready to cook yield and liver fat content decreased, while the relative weights of gizzard and intestine and protein content in liver increased, with increasing levels of SFM in the diet. 6. The concentration of HDL cholesterol increased while the concentration of LDL cholesterol decreased with increasing content of SFM (≥67% of SBM) in diet. The serum protein concentration decreased progressively with increase in dietary SFM. The concentrations of protein and triglycerides in serum were lowest in groups receiving SFM100. 7. Body weight gain was not affected by total replacement of SBM with SFM at 42 d of age. However, considering food efficiency, carcase yields, serum lipid profile and level of supplemental fat in diet, it is concluded that SFM can replace up to two-thirds of soybean, corresponding to inclusion of 345 and 296 g SFM per kg for starter and finisher phases, respectively.

The effect of date fibre supplemented with an exogenous enzyme on the performance and meat quality of broiler chickens

1. Two experiments were conducted to evaluate the use of date fibre as a partial replacement of maize as a source of energy for growing broiler chicken. In experiment 1, date fibre was given alone to determine apparent metabolisable energy (AME) and apparent ileal digestibility of amino acids and crude fibre. 2. Date fibre had lower AME content (8·7 vs 13·6 MJ/kg) and apparent ileal digestibility coefficients for dry matter (0·35 vs 0·83), crude fibre (0·20 vs 0·54) and amino acids. 3. Based on the results of experiment 1, a growth study was conducted to test the effect of exogenous enzymes on the nutritive value of date fibre (experiment 2). 4. Three date fibre contents (5, 10 and 15%) with and without enzyme supplementation were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of experiment 2, 160 birds were randomly selected and slaughtered to evaluate carcase and meat quality traits as well as measuring ileal viscosity. 5. Substitution of maize by 10 and 15% date fibre significantly depressed AME. Enzyme supplementation did not improve crude fibre digestibility. The inclusion of date fibre in the diets except at 5% decreased average daily gains, feed intake and feed conversion ratio. 6. Addition of date fibre caused a significant increase in the weights of total digestive tract, pancreas and caecum. Addition of date fibre or the exogenous enzyme had no significant effect on carcase or meat quality characteristics. 7. Date fibre increased ileal digesta viscosity compared to the control. Addition of the exogenous enzyme decreased the viscosity of the basal diets but had no effect on the date fibre diets. 8. This study indicated that date fibre can be included at levels of 5% in broiler diets without affecting performance.

Effects of xylanase supplementation on between-bird variation in energy metabolism and the number of Clostridium perfringens in broilers fed a wheat-based diet

Three experiments were conducted to examine: (a) the apparent metabolisable energy (AME) contents, the level of non-starch polysaccharides (NSP), and the extract viscosity value of 9 wheat samples; (b) the efficacy of a xylanase in reducing between-bird variation for AME; and (c) the effect of a xylanase on the number of Clostridium perfringens in broilers fed a low AME wheat diet. Experiment 1 revealed that the AME value of wheat varied from 11.5 to 13.6 MJ/kg dry matter (DM), which negatively correlated with the total NSP level (r = –0.97). Experiment 2 involved a 48-cage individual bird trial, where xylanase increased (P &lt; 0.05) the AME from 12.51 to 13.09 MJ/kg DM and reduced (P &lt; 0.05) its standard deviation from 1.13 to 0.52. The standard deviation for feed conversion ratio, ileal viscosity, and faecal viscosity was also reduced. In this experiment, there was a strong correlation between AME and excreta viscosity (r = –0.81) and the caecal xylanase activity of birds fed the control diet was positively correlated with AME (r = 0.72). In Expt 3, xylanase reduced the number of Clostridium perfringens, the causative agent for necrotic enteritis, to a non-detectable level in the ileum and caeca of broilers fed a low-ME wheat diet.

Pectinase Plays an Important Role in Stimulating Digestibility of a Corn-Soybean Meal Diet in Broilers

In our previous experiment, neither cellulase (Cell) nor hemicellulase (Hem) was effective in improving digestibility of corn-soybean meal diet in broiler chickens. As pectin is an important component in the cell wall matrix together with cellulose and hemicellulose, the effect of pectinase (Pec) and its combination with other carbohydrases were tested in the present study. The enzymes were mixed with the basal diet (CP 21%, ME 3000kcal/kg) and fed to male broiler chickens (Cobb) for 12 days from 15-d of age. Feed and water were offered ad libitum. Chicks were raised in a 25°C environment in wire bottom cages during the entire experimental period. Pectinase had no significant effect on any of the parameters measured. However, the combination of Pec with Cell or Hem led to significant improvement in the ileal digestibilities of crude protein and organic matter and increased apparent metabolizable energy content of the corn-soybean meal diet. Carcass yield was improved by all the enzyme combinations. Breast muscle weight was significantly increased by Pec+Hem and Pec+Cell+Hem and tended to be increased by Pec+Cell. All of the enzyme combinations had no significant effects on body weight gain, feed intake, feed conversion ratio and abdominal fat content. The results show the importance of Pec as a feed enzyme to improve the digestibility of a corn-soybean meal broiler diet.

Effect of cultivar and enzyme supplementation on nutrient availability and performance of broilers fed Maritime Canadian wheat

The feeding value of wheat is affected by the content of soluble non-starch polysaccharides (NSP), which varies among cultivars and the environment in which they are grown. Dietary enzymes can reduce the negative effects of NSP and improve the apparent metabolizable energy (AME) content of the wheat. This study examined differences in feeding value of four wheat cultivars grown in 2 crop years in the Maritime provinces of Canada and the need for enzymes. In a growth trial, diets containing one of the Maritime wheats or corn were fed with or without commercial enzymes containing, for wheat-based diets a mixture of xylanase and protease, and for corn-based diets a mixture of xylanase, protease, and amylase. In a broiler chick bioassay, diets containing 80% wheat were fed with or without a commercial enzyme with xylanase and protease activities. Enzymes significantly lowered body weight gain of birds fed Walton wheat in the second year, and improved the grower feed conversion ratio of birds fed Norboro wheat. Enzyme supplementation significantly improved apparent metabolizable energy and digestibility of crude protein. The AME content did not appear to be a direct indicator of performance. There were significant differences in AME content among the wheat samples. Enzymes generally did not improve performance in this study, possibly due to the relatively low in vitro viscosity values of these samples. Maritime wheats were equal or compared favourably with the sample of wheat from Western Canada and to locally obtained corn. Key words: Wheat, broiler performance, apparent metabolizable energy, enzyme

Effect of enzyme supplementation on the metabolisable energy content of solvent-extracted rapeseed and sunflower seed meals for chicken, guinea fowl and quail

1. The nitrogen-corrected apparent metabolisable energy (AMEN) content of solvent-extracted rapeseed and sunflower seed (un-decorticated) meals in relation to species (chicken, guinea fowl and quail) and dietary addition of feed enzymes (0 or 0·5 g/kg diet) was evaluated by a diet replacement method in a 3 × 2 factorial design. 2. The metabolism trial was conducted at two substitution levels (200 and 400 g/kg diet) of each meal with or without supplementation of commercial enzyme preparation in 6 individuals or 6 groups of cockerels, guinea fowls and quails. 3. The experimental diets were fed for a period of 12 d followed by a 3-d collection period during which total feed consumed and droppings output were quantitatively recorded. 4. The AMEN values of rapeseed meal for cockerels, guinea fowls and quails were 8·4, 8·7 and 8·8 MJ/kg, respectively, while the corresponding values for sunflower seed meal were 6·1, 6·1 and 6·2 MJ/kg dry matter, without enzyme supplementation. 5. The AMEN value of rapeseed meal did not improve with enzyme supplementation. However, AMEN values of sunflower seed meal significantly increased with enzyme supplementation, from 6·1 to 6·5 MJ/kg dry matter. 6. Since AMEN values of rapeseed meal and sunflower seed meal were similar in chicken, guinea fowl and quail, values reported for chicken could, therefore, be used for guinea fowl and Japanese quail.

Causes for improvement in nutritive value of broiler chicken diets with whole wheat instead of ground wheat

1. Two experiments were conducted with broiler chicks to compare nutritive values of ground and whole wheat diets containing titanium oxide as indigestible marker. 2. In Experiment 1, a wheat and soy isolate based cold-pelleted diet, in which all the wheat was ground in a hammer mill to pass through a 3 mm sieve, was compared with a diet in which about half (375 g/kg) of the ground wheat was taken out of the diet and supplied as whole wheat mixed into the diet after pelleting. 3. In Experiment 2, a diet based on ground wheat and soy isolate which was pelleted after preconditioning (final temperature 81°C) was compared with a diet in which 500 g of the ground wheat was replaced by whole wheat mixed into the diet before pelleting. 4. In Experiment 1, replacement of ground wheat with whole wheat increased apparent metabolisable energy (AME) content and starch digestibility measured at ileal as well as faecal level, while weight gain and feed conversion efficiency (FCE) were not affected. Jejunal chyme showed increased amylase activity and bile salt concentration. 5. In Experiment 2, replacement of ground wheat with whole wheat increased dry matter content as well as bile content of gizzard, and stimulated an increase in gizzard as well as pancreas weight. Jejunal amylase and bile concentrations were not significantly affected and neither were growth, FCE or AME. 6. Results from this experiment indicate that the improved feed value sometimes observed with whole wheat may be associated with modulation of digestive processes resulting in increased pancreas and liver secretions.

The effect of site of starch digestion on performance of broiler chickens

A growth trial with 420 broiler chickens (35 per experimental unit) was conducted in order to evaluate whether bird performance (Days 0–38) is affected by site of starch digestion. Two diets were formulated with the same calculated apparent metabolisable energy, digestible lysine, and digestible starch content. The diets contained starch sources with known amounts of rapidly digestible starch (RDS, starch digested until the posterior jejunum) and slowly digestible starch (SDS, starch digested in the ileum). Diets were either high (H) or low (L) in SDS content. RDS and SDS contents were 298 and 52 g/kg for the H diet and 345 and 7 g/kg for the L diet, respectively. Starch in the H diet was supplied by waxy maize, peas and sorghum and starch in the L diet was supplied by tapioca and common maize. Birds receiving the H diet consumed more feed ( P<0.10), grew faster ( P<0.01) and had a lower feed conversion ratio ( P<0.01) than birds receiving the L diet. The results suggest that broiler chickens perform better on diets containing a minimal amount of slowly digestible starch. Future experiments are necessary to investigate the relation between amount of slowly digestible starch and performance of broiler chickens.

Effects of inclusion with blue lupins ( Lupinus angustifolius) in broiler diets and enzyme supplementation on production performance, digestibility and dietary AME content

An experiment with broiler chickens was conducted to study the effect of inclusion of blue lupins and exogenous enzyme to broiler diets on the apparent metabolisable energy (AME), digestibility and performance. Two basal diets were formulated: a non-lupin diet A based on soya bean meal and maize, and a diet B where parts of soya bean meal and maize were substituted with blue lupin (200 g/kg). The two basal diets were fed either alone or, for diet B in combination with different enzyme preparations (Bio-Feed Plus, lactase, two galactanases (Gal-I and Gal-II)). The experiment was performed in battery cages with 648 male broiler chickens, where eight experimental diets were fed to the chickens from 7 to 21 days of age and weight gain and feed intake were measured during the period. At the end of the experiment, three chickens from each pen were slaughtered and the content from jejunum and ileum was separately collected and pooled and used for measurement on intestinal viscosity. For measurements of the apparent metabolisable energy and the apparent digestibility, excreta were collected at 22–24 days of age and ileal contents collected at 25–26 days from the remaining chickens. Substitution of soya bean meal and maize with blue lupin depressed weight gain (9%) and feed conversion ratio (12%) significantly. Feed intake of the lupin-based diets was not decreased. The protein in lupin was digested to the same extent as the protein from soya bean meal, the coefficient of ileal apparent digestibility being on average 0.75. However, the high content of the non-starch polysaccharides (NSP; 450 g/kg) in lupin depressed the apparent digestibility of the organic matter by approximately 10%. The AME n of the non-lupin diet was 14.01 MJ/kg dry matter (DM) compared to a value of 13.11 MJ/kg DM in the lupin control diet. Improvements in the measured parameters were seen with some of the enzymes. Gal-I, and Gal-II in combination with lactase were the most efficient enzymes concerning improvement in AME n and performance. Weight gain was increased by 3.5–5.5% by addition with these enzymes. Gal-I increased the AME n significantly to 13.65 MJ/kg, a value not significantly different from the AME n of the non-lupin diet. There was no effect of addition with the different enzymes on the coefficients of apparent digestibility of organic matter measured in the ileum, whereas addition with Gal-I to the lupin diet increased the apparent digestibility of organic matter over the total tract by 3%. The mode of action of the galactanases has been to hydrolyse the galactan in the NSP cell wall of lupins to galactose and dimers of galactose, which are energy-yielding to poultry. From the results obtained, it can be indicated that Gal-I increased the energy utilisation of the lupin-based diet, confirmed by the improved AME n content and performance.

Effects of prepress-solvent extraction on the nutritional value of canola meal for broiler chickens

The objective of the experiment was to determine if standard prepress-solvent extraction of canola (low glucosinolate, low erucic acid rapeseed) affects the nutritional value of the resulting meal for broiler chickens. Three sets of samples were collected from all stages of prepress-solvent extraction at a commercial crushing plant and examined for nutritional value. Except for cystine and serine, processing stages up to and including solvent extraction did not affect coefficient of apparent ileal digestibility (CAID). However, the desolventization/toasting process reduced ( P<0.05) lysine content (6.03–5.50 g/16 gN), crude protein CAID (0.81–0.77), lysine CAID (0.87–0.79) and the CAID of all the other amino acids except glutamine, leucine, methionine and serine. Desolventization/toasting increased the coefficient of variation (percent CV) for the CAID of lysine over the solvent extracted meal (5.6% versus 1.4%) and all the other amino acids except glutamine, histidine, leucine, and serine. As expected, apparent metabolizable energy (AME) content decreased ( P<0.05) with expelling and solvent extraction due to the reduced oil content, but was not affected by other processing stages. In conclusion, commercial desolventization/toasting can reduce the content and CAID of many amino acids in canola meal and increase the level of variability in nutritional value between canola meal samples.

Influence of Phytase and Xylanase Supplementation on Growth Performance and Nutrient Utilisation of Broilers Offered Wheat-based Diets

Individual and combined supplementation of phosphorus-adequate, wheat-based broiler diets with exogenous phytase and xylanase was evaluated in three experiments. The effects of the enzyme combination in lysine-deficient diets containing wheat and sorghum were more pronounced than those of the individual feed enzymes. The inclusion of phytase plus xylanase improved (p<0.05) weight gains (7.3%) and feed efficiency (7.0%) of broilers (7-28 days post-hatch) and apparent metabolisable energy (AME) by 0.76 MJ/kg DM. Phytase plus xylanase increased (p<0.05) the overall, apparent ileal digestibility of amino acids by 4.5% (0.781 to 0.816); this was greater than the responses to either phytase (3.6%; 0.781 to 0.809) or xylanase (0.7%; 0.781 to 0.784). Absolute increases in amino acid digestibility with the combination exceeded the sum of the individual increases generated by phytase and xylanase for alanine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, phenylalanine, threonine, tyrosine and valine. These synergistic responses may have resulted from phytase and xylanase having complementary modes of action for enhancing amino acid digestibilities and/or facilitating substrate access. The two remaining experiments were almost identical except wheat used in Experiment 2 had a higher phytate concentration and a lower estimated AME content than wheat used in Experiment 3. Individually, phytase and xylanase were generally more effective in Experiment 2, which probably reflects the higher dietary substrate levels present. Phytase plus xylanase increased (p<0.05) gains (15.4%) and feed efficiency (7.0%) of broiler chicks from 4-24 days post-hatch in Experiment 2; whereas, in Experiment 3, the combination increased (p<0.05) growth to a lesser extent (5.6%) and had no effect on feed efficiency. This difference in performance responses appeared to be 'protein driven' as the combination increased (p<0.05) nitrogen retention in Experiment 2 but not in Experiment 3; whereas phytase plus xylanase significantly increased AME in both experiments. In Experiments 2 and 3 the combined inclusion levels of phytase and xylanase were lower that the individual additions, which demonstrates the benefits of simultaneously including phytase and xylanase in wheat-based poultry diets.

Comparison of two direct bioassays using 3-week-old broilers to measure the metabolisable energy of diets containing cereals high in fibre: Differences between true and apparent metabolisable energy values

1. Nitrogen-corrected apparent and true metabolisable energy contents (AMEN and TMEN) of 12 diets, containing different amounts of maize, wheat, barley and rye, barley with β -glucanase and maize with 0.05 g/kg guar gum were measured using 3-week-old male broilers. 2. The AMEN method involved: 4 d of dietary adaptation, 24 h of starvation, 54 h of ad libitum feeding, 24 h of starvation and daily total droppings collection. TMEN was measured after a 48 h starvation period followed by 2 d of tube-feeding two doses of 15 g of the diets and quantitatively collecting all the droppings after 48 h of starvation. The endogenous energy losses (EELN) were measured after tube-feeding 8 chickens with 30 g of glucose, also over 2 d. 3. The results show that a significant interaction exists between the nature of the diets and the method used to measure metabolisable energy. Differences between TMEN and AMEN values ranged from 1.03 to 1.98 MJ/kg dry matter. These differences were positively correlated with the total pentosan contents of the diet (r = 0.94), the natural logarithm of the viscosities of the water extracts (r = 0.87), the sum of the contents of total pentosans and total β -glucan (r = 0.85), the calculated total non-starch polysaccharide contents (r = 0.79), the neutral detergent fibre contents (r = 0.76) and the total β -glucan contents (r = 0.70). Furthermore, a significant interaction was found between diets and the method used to derive lipid digestibility. The differences between apparent and true lipid digestibility ranged from 0.05 percentage points for the wheat diet to 0.20 percentage points for the rye diet. 4. From the results of this trial, it appears that TMEN overestimates the energy value of high fibre diets.

Effects of preservation method and β-glucanase supplementation on ileal amino acid digestibility and feeding value of barley for poultry

1. Effects of preservation method (drying or air-tight storage of whole grain and ensiling of rolled high-moisture grain) and β -glucanase supplementation (Econase®) on apparent ileal amino acid digestibilities and metabolisable energy content of barley were evaluated with Ross broiler chickens. In addition, the effect of barley preservation method was assessed using Leghorn cockerels. 2. Birds were given either a semi-purified soyabean meal basal diet or a mixture of the basal diet and barley (50:50 on dry matter basis). Apparent ileal digestibilities (AID) of nutrients were assessed using the slaughter technique. AID of nutrients and nutrient digestibility measured using excreta (AED) were determined using chromium mordanted straw as an indigestible marker. 3. In broilers, AID of amino acids, dry matter and organic matter were lower for dried than air-tight stored barley, particularly for diets based on ensiled barley. In cockerels, barley preservation method had no effect on amino acid AID. The AED of nutrients and nitrogen corrected apparent metabolisable energy content (AME n ) was highest for ensiled barley across both experiments. 4. β -glucanase supplementation increased nutrient digestibility, phosphorus retention and AME n content of airtight stored and dried barley diets in particular but had only negligible effects on ensiled barley. β -glucanase improved the AID of amino acids in dried barley but not in air-tight stored or ensiled barley. 5. Amino acid digestibilities were lower in broilers than cockerels and the effect of barley preservation on feeding value of barley was different for broilers and cockerels.

Replacement of soybean meal with roasted full-fat soybeans from high-protein or conventional cultivars in diets for broiler chickens

The effects were examined of replacing part or all of the soybean meal in the starter and finisher diets for male broiler chickens with ground, roasted, full-fat soybeans from either a high-protein (AC Proteus) or conventional (Baron) cultivar. The starter (1–21 d) and finisher (22–36 d) diets were formulated by replacing, on an isonitrogenous basis, part or all of the soybean meal in the barley–wheat-based control diets with the roasted soybeans. Digestibility of dry matter, corrected nitrogen and energy were estimated by an index method for the last 2 d of the starter and grower periods. Soybean level influenced body weight gains directly in a quadratic manner, and feed intakes or feed conversions by inversely linear relationships (P &lt; 0.05 and P &lt; 0.01) during the starter period. Performance during the finisher period or during the entire growth period was not influenced (P &gt; 0.05) by dietary soybean source. Dry matter and energy digestibilities at both 21 and 35 d, and nitrogen at 35 d were affected in a quadratic manner (P &lt; 0.05 or P &lt; 0.01) by the soybean level of the diets, whereas, a linear relationship was present for the apparent metabolizable energy (AME) content (P &lt; 0.001). Soybean source had no effect on nutrient utilization, except for dry matter or energy digestibility during the starter period (P &lt; 0.01). In conclusion, the optimal performance should be obtained when the ratio of roasted full-fat soybeans to soybean meal is about 2:1 in the starter feeds for broiler chickens. Key words: Full-fat soybeans, soybean meal, high-protein soybeans, broiler, growth, nutrient digestibilities

Metabolisable energy content of diets and broiler performance as affected by wheat specific weight and enzyme supplementation

1. Two experiments were performed with male, Ross broiler chicks to study the relationship between wheat specific weight and performance parameters and the effects of xylanase inclusion in diets of different wheat specific weight (SW). 2. In both studies wheat was incorporated at 667 g/kg and a protein concentrate based on soyameal 50, full fat soyameal, extrupro and herring meal and formulated to provide (g/kg) crude protein 370, crude oil 140, crude fibre 45, crude ash 110 was incorporated at 333 g/kg. 3. In Experiment 1, 3 wheats (69, 67, 57, SW respectively) without or with enzyme (Avizyme TX, Finnfeeds International) and in Experiment 2, 6 wheats (81, 77, 76, 70, 64, 61 SW respectively) were used and diets were fed ad libitum to individually caged birds. 4. In Experiment 1 the feeding period was 7 to 28 d and a total excreta collection was made from 14 to 20 d for determination of apparent metabolisable energy (AME) content. Experiment 2 started at 4 d with excreta collections from d 6 to 9, 10 to 12 and 13 to 19 inclusive for AME measurements. 5. In Experiment 1 there were no significant effects of wheat on dry matter (DM) intake but liveweight gain (LWG) and gain:food were significantly better for 67 SW than for 57 SW. Food enzyme inclusion improved LWG and gain:food but there was a significant wheat/enzyme interaction for gain:food with no improvement due to enzyme addition for 67 SW but a 5% improvement for 57 SW. There was no significant effect of wheat or enzyme addition on the measured AME contents of the diets. 6. In Experiment 2, although not statistically significant, there were large numerical differences in food intake between diets, with the lowest values occurring for 64 SW. For the complete period, wheat variety tended to affect LWG ( P =0.057) with the best and worst results recorded for the 2 low SW wheats. Gain:food was significantly affected by wheat, the poorest values occurring with 64 SW and the best with 77 SW. Diet AME content was also affected by wheat variety ( P <0.01) but the low result obtained for 61 SW was not mirrored in the gain:food value. The lack of correlation between diet AME values and gain:food could not be attributed to differences in protein or amino acid content of the diets. 7. In Experiment 2 diet AME content increased from period 1.1 (6 to 9 d) to period 2 (13 to 20 d) by 7% but interpretation is hampered by the short adaptation period (2 d) prior to period 1.1. The AME values obtained in both studies during the 3rd week of age were towards the upper end of the range of values in the literature. 8. In Experiment 2 there was a good correlation ( r 2=0.95) between SW and wheat starch content and between SW and calculated wheat AME content ( r 2=0.40, P <0.001) but a poor correlation between SW and gain:food. There was also a high correlation between wheat AME content and starch content ( r 2=0.41, P <0.001). Taken together with the results of Experiment 1 it appeared that starch content is a better measure of wheat quality than specific weight.