Interaction between xylanase and phytase on the digestibility of corn and a corn/soy diet for broiler chickens.

An experiment was carried out to evaluate the digestibility and metabolizability of corn and a corn/soy-based diet with the inclusion or not of xylanase and/or phytase in broilers. In the trial, 1,120 broiler chicks were distributed according to a completely randomized experimental design, consisting of 16 treatments, with 10 replicates of 7 birds each. Treatments were evaluated following a factorial arrangement (4 × 2 × 2), with 4 xylanase levels (zero, 50, 100, or 150 fungal ß-xylanase units/kg; FXU), 2 phytase levels (zero or 1,000 phytase units/kg; FTU), and 2 diets (corn/soy or pure corn). The same basal diets were fed from one to 14 d post hatch for all birds, after which the experimental diets were provided until d 25. All birds were euthanized on d 25 for collection of ileal contents. Samples of feed, excreta, and ileal digesta were analyzed for determination of apparent ileal digestibility. The effect of xylanase on the coefficient of apparent dry matter metabolizability and apparent metabolizable energy was increased by the presence of phytase in the complete diet but not in the diet based on pure corn resulting in a diet*phytase*xylanase interaction (P < 0.01; P < 0.001, respectivaly). Equivalent effects were observed for the apparent coefficient of ileal protein digestibility in which xylanase effects were potentiated by the presence of phytase only in the complete diet, resulting in a significant 3-way interaction. In corn there was a limitation in improving digestibility when we added increasing levels of xylanase with phytase. Otherwise in the corn/soy-based diets, the enzymes were potencialized when they were added together. The fact that the effect of xylanase was enhanced by the presence of phytase in complete diets but not in pure corn may be associated with differences in substrate (arabinoxylan and/or phytate) concentration and presentation, diet nutrient balance, or other factors. It can be concluded that the interactive effects of xylanase and phytase can be substantial but may depend on the characteristics of the diet fed.

Reduced Nutrient Excretion and Environmental Microbial Load with the Addition of a Combination of Enzymes and Direct-Fed Microbials to the Diet of Broiler Chickens

This study evaluated the effects of the dietary inclusion of an enzyme blend and a direct-fed microbials in broiler diets on litter production and quality. In total, 900 Cobb 500(r) broiler chicks were distributed according to a completely randomized design into 4 treatments and 9 replicates of 25 birds each. Broilers were reared from 1 to 42 days of age. The treatments consisted of the following diets: NC: negative control; DFM: NC + 500 ppm of direct-fed microbials product (DFM), containing Bacillus subtilis and Bacillus licheniformis; ENZ: diet formulated with an enzyme blend (20 ppm phytase, 200 ppm protease and 200 ppm of xylanase); DFM+E: ENZ + DFM. Birds and litter were weighed at the start and end of the rearing period, for litter production and waste ratio (Rw) determination. Litter samples were analyzed for dry matter (DM) content, total and thermotolerant coliform counts, nutrient composition (nitrogen (N), phosphorous (P) and potassium (K)), and fiber fraction (neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin). The dietary inclusion of the evaluated additivesdid not influence litter production or Rw; however, ADF (%), NDF (kg and kg/kg DM litter), and total and thermotolerant coliform counts were reduced, and N content increased in the litter. The diets containing enzymes (ENZ and DFM+E) reduced litter P content. The addition of exogenous enzymes and their combination with a DFM based on Bacillus spp .Did not affect waste production, and reduced litter microbial load, and the contents of P and insoluble fiber in the litter.(AU)

Reduced Nutrient Excretion and Environmental Microbial Load with the Addition of a Combination of Enzymes and Direct-Fed Microbials to the Diet of Broiler Chickens

This study evaluated the effects of the dietary inclusion of an enzyme blend and a direct-fed microbials in broiler diets on litter production and quality. In total, 900 Cobb 500(r) broiler chicks were distributed according to a completely randomized design into 4 treatments and 9 replicates of 25 birds each. Broilers were reared from 1 to 42 days of age. The treatments consisted of the following diets: NC: negative control; DFM: NC + 500 ppm of direct-fed microbials product (DFM), containing Bacillus subtilis and Bacillus licheniformis; ENZ: diet formulated with an enzyme blend (20 ppm phytase, 200 ppm protease and 200 ppm of xylanase); DFM+E: ENZ + DFM. Birds and litter were weighed at the start and end of the rearing period, for litter production and waste ratio (Rw) determination. Litter samples were analyzed for dry matter (DM) content, total and thermotolerant coliform counts, nutrient composition (nitrogen (N), phosphorous (P) and potassium (K)), and fiber fraction (neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin). The dietary inclusion of the evaluated additivesdid not influence litter production or Rw; however, ADF (%), NDF (kg and kg/kg DM litter), and total and thermotolerant coliform counts were reduced, and N content increased in the litter. The diets containing enzymes (ENZ and DFM+E) reduced litter P content. The addition of exogenous enzymes and their combination with a DFM based on Bacillus spp .Did not affect waste production, and reduced litter microbial load, and the contents of P and insoluble fiber in the litter.

Efficacy and Metabolizable Energy Equivalence of an -Amylase--Glucanase Complex for Broilers

A trial was conducted to evaluate the effects of adding an exogenous -amylase--glucanase complex produced from Bacillus amyloliquefaciens on the growth performance, carcass yield, and relative AME bioequivalence in broilers fed corn-soy diets from 1 to 40 d of age. One thousand seven hundred and fifty one-day-old Cobb x Cobb 500 slow-feathering male broilers were randomly allotted to seven treatments with 10 replicates of 25 birds each as follows: control diet (C); C diet with reduction of 60 (C-60), 90 (C-90), or 120 (C-120) kcal AME/kg; C diet with reduction of 120 kcal AME/kg and supplemented with 200 (C-120-200), 300 (C-120-300), or 400 (C-120-400) mg of the enzyme complex/kg. Each g of the enzyme complex corresponded to 200 kilo-Novo -amylase and 350 fungal -glucanase units. On d 40, eight birds were randomly taken from each pen and processed to evaluate carcass and commercial cuts yields. Percent mortality was not affected by the treatments (p > 0.05). Live performance, as indicated by BW gain (BWG) linearly decreased (p 0.05) and FCR linearly increased with the reduction in AME. Birds fed diets supplemented with the enzyme complex showed weekly improvements in BWG and FCR. There were no effects of the treatments on the yield of the carcass or of commercial cuts; however, abdominal fat was significantly lower (p 0.0343) in birds fed the C-120-400 compared to the C-120 feeding program (1.67% vs. 1.90%); all other treatments were intermediate. Average AME equivalence of the enzyme complex varied weekly. Estimations for the entire period were 40, 46, and 56 kcal for BWG and 58, 76, and 99 kcal AME/kg for FCR (p 0.001) for the diets containing 200, 300, and 400 mg enzyme complex/kg, respectively.

Efficacy and Metabolizable Energy Equivalence of an -Amylase--Glucanase Complex for Broilers

A trial was conducted to evaluate the effects of adding an exogenous -amylase--glucanase complex produced from Bacillus amyloliquefaciens on the growth performance, carcass yield, and relative AME bioequivalence in broilers fed corn-soy diets from 1 to 40 d of age. One thousand seven hundred and fifty one-day-old Cobb x Cobb 500 slow-feathering male broilers were randomly allotted to seven treatments with 10 replicates of 25 birds each as follows: control diet (C); C diet with reduction of 60 (C-60), 90 (C-90), or 120 (C-120) kcal AME/kg; C diet with reduction of 120 kcal AME/kg and supplemented with 200 (C-120-200), 300 (C-120-300), or 400 (C-120-400) mg of the enzyme complex/kg. Each g of the enzyme complex corresponded to 200 kilo-Novo -amylase and 350 fungal -glucanase units. On d 40, eight birds were randomly taken from each pen and processed to evaluate carcass and commercial cuts yields. Percent mortality was not affected by the treatments (p > 0.05). Live performance, as indicated by BW gain (BWG) linearly decreased (p 0.05) and FCR linearly increased with the reduction in AME. Birds fed diets supplemented with the enzyme complex showed weekly improvements in BWG and FCR. There were no effects of the treatments on the yield of the carcass or of commercial cuts; however, abdominal fat was significantly lower (p 0.0343) in birds fed the C-120-400 compared to the C-120 feeding program (1.67% vs. 1.90%); all other treatments were intermediate. Average AME equivalence of the enzyme complex varied weekly. Estimations for the entire period were 40, 46, and 56 kcal for BWG and 58, 76, and 99 kcal AME/kg for FCR (p 0.001) for the diets containing 200, 300, and 400 mg enzyme complex/kg, respectively.(AU)

Intestinal bacterial community and growth performance of chickens fed diets containing antibiotics.

This study was conducted to relate the performance of broiler chickens fed diets containing growth-promoting antibiotics to changes in the intestinal microbiota. The technique of denaturing gradient gel electrophoresis (DGGE) of amplicons of the region V3 of 16S rDNA was used to characterize the microbiota. Two experiments were conducted, one with broilers raised in battery cages and the other with broilers raised in floor pens. Antibiotics improved the performance of the chickens raised in floor pens only. Avilamycin, bacitracin methylene disalicylate, and enramycin induced changes in the composition of the intestinal bacterial community of the birds in both experiments. The number of bacterial genotypes found in the intestinal tract of chickens was not reduced by the antibiotics supplemented in either environment. However, the changes in the composition of the intestinal bacterial community induced by antibiotics may be related to improvement in growth performance. This was indicated by the suppression of 6 amplicons and the presence of 4 amplicons exclusive to the treatment that had the best performance in the floor pen experiment.