The effects of adding xylanase, vitamin C and copper sulphate to wheat-based diets on broiler performance

Interactive effects of dietary protein concentration, a mono-component exogenous protease and ascorbic acid on broiler performance, nutritional status and gut health

A total of 640 male Ross 308 broiler chickens were used to explore the interactive effects of diet nutrient density, exogenous protease and ascorbic acid on performance, nutrient digestibility and various gut health metrics. A total of eight dietary treatments were arranged as a 2 × 2 × 2 factorial with the factors being adequate or reduced (~4%) crude protein and amino acids, without or with exogenous protease and without or with supplemental ascorbic acid. Over the 35-day experimental period, birds that received the adequate diet had higher (P < 0.01) bodyweight gain and lower (P < 0.001) feed conversion ratio (FCR) than birds that received the diet with reduced protein and amino acid density. Supplemental protease reduced (P < 0.001) FCR and this influence was more apparent in birds fed the diet with reduced protein concentration. Gut tensile strength tended to be increased by protease (P = 0.09) and ascorbic acid (P = 0.06) supplementation. Supplemental protease reduced (P < 0.001) jejunal goblet cell numbers and epithelial thickness and increased (P < 0.05) villus height compared with unsupplemented diets. Ascorbic acid tended (P = 0.05) to increase sialic acid concentration in ileal digesta. Protease increased (P < 0.01) the coefficients of apparent ileal digestibility for all amino acids other than methionine and this effect tended (P = 0.07 to 0.09) to be more pronounced in the low protein diet for aspartic acid, histidine and arginine. The concentration of taurine in ileal digesta was reduced (P < 0.01) by protease whereas hydroxyproline concentrations tended (P = 0.09) to increase by ascorbic acid addition. These results confirm previous reports on the effectiveness of exogenous protease in diets reduced in crude protein and digestible amino acids. Furthermore, both protease and ascorbic acid may influence gut health through promotion of tensile strength, epithelial morphology and endogenous protein flow. The interaction between exogenous protease and ascorbic acid on gut health with an emphasis on collagen structure and tight junction integrity is an area for future study.

Effects of diets supplemented with zinc and manganese on performance and related parameters in laying hens

Iron is often found to be of excessive concentrations in laying hens' diets, which may cause antagonistic interactions with other minerals. This study was conducted to investigate how to supplement Zn and Mn in the diets without Fe supplementation. In experiment 1, 420 18-week Lohmann Brown layers were fed a basal diet or a basal diet supplemented with 30-0, 65-30 and 100-60 mg/kg of Zn and Mn, respectively. In experiment 2, 360 40-week Lohmann Brown layers were fed a basal diet or a basal diet supplemented with 15-0, 35-0 and 55-15 mg/kg of Mn and Zn, respectively. Minerals were supplemented in the form of sulfate. Egg production was improved by supplementing 30 mg/kg Zn or 65 mg/kg Zn in combination with 30 mg/kg Mn in experiment one. In experiment two, a significant reduction of egg performance occurred with 35 mg/kg Mn supplementation. Mn and/or Zn supplementation increased eggshell thickness in experiment one, and decreased yolk cholesterol in both experiments. Mn and/or Zn supplementation increased Zn and Mn excretion in both experiments. Serum growth hormone (GH), thyroxine (T(4) ), and insulin levels, or alkaline phosphatase (AP) activity were not affected by treatments; serum estrogen (E(2) ) and triiodothyronine (T(3) ) were different but there was no consistency by dietary treatments. This study demonstrates that 30 mg/kg supplemental Zn is necessary to obtain maximal egg production, and there seems to be no need to supply Mn in this type of diet.

Limitations to wheat starch digestion in growing broiler chickens: a brief review

Starch digestibility may be suboptimal in broilers fed pelleted wheat-based diets. In the present review, the digestion and absorption process related to starch is presented, followed by a discussion of the effect of wheat characteristics and bird-related effects. Enzyme secretion or glucose absorption and metabolism have not been shown to be limiting factors. Suboptimal starch digestibility is primarily observed when a large proportion of wheat is included in the diet, and appears to be partly associated with characteristics of the wheat such as hardness and cell wall structure, which cause starch granules to remain entrapped in the protein matrix and the cell wall of the endosperm or aleurone layer. There are indications that low starch digestibility is negatively correlated with feed intake, and that such a feed over-consumption is linked to an under-developed gizzard.

Effects of food deprivation and particle size of ground wheat on digestibility of food components in broilers fed on a pelleted diet

The first aim of the experiment was to study the effect of wheat (Triticum aestivum) particle size on the digestibility of starch in a pelleted diet given to broilers. The second aim was to study the consequences of food deprivation before the excreta collection period (from 21 to 24 d). Wheat from a strong hardness cultivar was incorporated at 546.1 g/kg in diets. The other main ingredients were soybean meal (353.5 g/kg) and rapeseed oil (55.0 g/kg). Diets were given as pellets. The experimental design was a 2 x 2 factorial design testing two particle sizes of wheat flour and two procedures of a balance experiment (with or without food deprivation). Birds given diet C (wheat coarse grinding before pelleting) had significantly greater gizzard weight than birds fed on diet F (wheat fine grinding before pelleting). Starch digestibility value was significantly increased when birds were fed on diet F. This effect was halved by food deprivation. No significant effect of grain particle size was observed for protein and lipid digestibility values. However, food deprivation decreased apparent protein digestibility, with an effect which was more pronounced for fine than for coarse grinding. AMEN of the diet was significantly improved by fine grinding of wheat and decreased by food deprivation. However, no significant differences in growth performance were induced by differences in wheat grinding. No significant effect of grinding was observed on the water excretion:feed intake ratio. No significant difference was observed for vent score between treatments. There was over-excretion of starch in the first hours of refeeding following food deprivation.

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.

Feed formulations to reduce N excretion and ammonia emission from poultry manure

This summary focuses on reducing nitrogen (N) and ammonia emissions from poultry manure through the use of improved amino acid digestibilities and enzyme supplementation. Proper feed processing techniques, phase feeding, and the minimization of feed and water waste can contribute to additional minor reductions in these emissions. Reductions in environmental pollution can be achieved through improved diet formulation based on available nutrients in the ingredients, reducing crude protein (CP) levels and adding synthetic amino acids. Use of amino acid and CP digestibilities can reduce N excretion up to 40% and a 25% increase in N digestibility can be achieved with enzyme supplementation in broiler diets. Digestibilities can be measured by two methods: the excreta and ileal amino acid digestibilities. Both methods allow amino acid levels to be reduced by 10% or more. Enzyme supplementation decreases intestinal viscosity, improves metabolizable energy levels, and increases amino acid digestibilities. Many feed manufacturers still use total amino acid content to formulate feeds. To meet amino acid requirements, crystalline amino acids are needed. The use of feather, meat and bone meal must not be overestimated or underestimated and the limiting amino acids such as cystine, tryptophan, and threonine must be carefully analyzed.

Exogenous dietary xylanase ameliorates viscosity-induced anti-nutritional effects in wheat-based diets for White Pekin ducks (Anas platyrinchos domesticus)

Nutrient utilisation and growth performance responses of White Pekin ducks (Anas platyrinchos domesticus) offered diets containing low- or high-viscosity wheat supplemented with xylanase were investigated in two studies. In Expt 1, six diets consisting of low-viscosity wheat or high-viscosity wheat supplemented with 0·0, 1·5 or 3·0 g xylanase (2590 units/g)/kg diet were used in a true metabolisable energy (TME) bioassay with eight 8-week-old ducks per diet group. In Expt 2, eight pens of ten 3-d-old ducks per pen for each of six wheat-based diets arranged in a 2×3 factorial of low-viscosity or high-viscosity wheat and 0·0, 1·5 or 3·0 g xylanase/kg were used in a 42 d growth study. High-viscosity wheat depressed (P>0·001) TME and xylanase supplementation improved (P>0·001) TME, more so for high-viscosity than low-viscosity wheat. Xylanase supplementation of the high-viscosity wheat-based diet improved (P>0·05) weight gain and gain:feed ratio by 13 and 12% respectively. There was no weight gain or gain:feed ratio response to xylanase supplementation of the low-viscosity wheat-based diet. Xylanase supplementation reduced (P>0·001) the viscosity of duodenal and ileal digesta for high-viscosity but not low-viscosity wheat-based diets. Ileal digestibilities of nutrients and energy were higher (P>0·001) for low-viscosity than high-viscosity wheat-based diets; xylanase supplementation improved (P>0·05) energy, fat, N and starch digestibilities. Given that xylanase supplementation of high-viscosity wheat assuaged its anti-nutritional effect, it is surmised that digesta viscosity plays a role in anti-nutritional effects in wheat-based diets for ducks.

Supplementation of Avizyme 1502 to corn-soybean meal-wheat diets fed to turkey tom poults: the first fifty-six days of age

A study was designed to determine the effects of enzyme supplementation on poults fed commercially based diets that included corn, soybean meal, and ground wheat with meat and bone meal (0 to 21 d) or Pro-Pak (22 to 56 d). Day-old turkey poults (n = 3,850) were divided into 35 pens and fed 1 of 5 dietary treatments for 56 d. Treatments were a positive control, a negative control (corn matrix adjustment of 140 kcal), and negative control diets supplemented with Avizyme 1502 at 250, 500, or 750 g/tonne. Feed intake, live weight gain, feed conversion ratio, and mortality were measured for the periods 0 to 21 d, 21 to 42 d, and 42 to 56 d, as well as for the cumulative 0 to 56 d. The 0- to 21-d period was further divided into subperiods (0 to 4 d, 4 to 8 d, 8 to 12 d, 12 to 16 d, 16 to 21 d) to evaluate early nutritional development. Ileal contents along with duodenal, jejunal, and ileal sections (n = 7/treatment) were sampled to determine apparent digestibility and morphology. In most instances, production response differences between the positive and negative controls were not significant, making definitive interpretation of enzyme addition difficult. Energy and protein ileal digestibilities of the negative control diets were lower than those of the positive control diet at 4, 8, 12, 16, and 42 d. Enzyme supplementation significantly improved energy and protein beyond that of the PC diet on d 42. Villus height and crypt depth did not respond to dietary treatment, although there was a significant interaction of age by treatment on jejunal villus height. The similarity between the controls, as well as the high inclusion of CuSO(4), may be responsible for the low response with enzyme inclusion.

Hagberg falling number and the nutritional value of wheat in broiler chicken diets

1. Three experiments were performed to study the effect of Hagberg falling number in wheat on performance, nutrient digestibility and AMEN in broilers. In two experiments, one hard and one soft wheat variety were used to study the interaction between falling number and hardness of wheat with regard to nutritional value. In these experiments, wheat batches with high falling number when harvested under dry conditions were used in broiler diets. 2. Wheat with reduced falling numbers (high, medium and low) was obtained by controlled germination. In the third experiment, wheat with reduced falling numbers were obtained by delayed harvesting times. 3. In each experiment, a total of 4 cereal batches with different falling numbers from each wheat variety were used to produce corresponding experimental diets with wheat as the major ingredient. Each diet was fed to broiler chickens ad libitum from d 1 to d 17 of age. 4. There was no consistent effect of falling number on performance. Low falling number did not improve feed utilisation or AMEN compared to the original wheat, despite a higher AMEN associated with higher starch digestibility. This phenomenon was not observed after reduction of falling number by delayed harvesting. Apparently, natural reduction of falling number resulted in enhanced degradation of arabinoxylans compared to controlled germination.

Effects of dietary copper on production and egg cholesterol content in laying hens

1. This experiment was carried out to determine the effects of diets supplemented with different amounts of copper on egg production, food intake, food conversion ratio, egg weight, damaged egg ratio, specific gravity, mortality and cholesterol concentration in yolk. The experiment lasted 90 d and 400 Hisex-Brown hens, aged 27 weeks at the start of the study, were used. 2. There were no statistically significant effects of supplementary copper on egg production, food intake or food conversion efficiency. 3. There were no statistically significant differences between the groups in terms of damaged eggs, egg weight, specific gravity and live weight. 4. At the end of the experiment, the lowest yolk cholesterol concentrations were obtained in the 150 kg/kg copper group and the greatest concentrations were in the control group. 5. Consequently, the use of supplementary copper to provide 150 kg/kg in poultry diets was concluded to decrease yolk cholesterol concentrations without any effect on production performance.