饲用酶制剂对生长猪营养物质消化利用率的影响

选择８头体重１７ｋｇ,在回肠末端安装改进“Ｔ”型瘘管的断奶公仔猪,随机分为两组,分别饲喂添加复合酶和对照日粮,进行两次重复代谢试验和回肠末端食糜消化酶活性测定。试验结果表明,酶制剂可使饲料中主要营养物质、氨基酸的消化利用率和回肠末端食糜中蛋白酶类的活性略有提高,但与对照日粮无显著差异。试验组对饲料干物质、有机物、粗蛋白质、粗灰分的消化率和消化能的转化率平均分别为８４．１６％,８８．７７％,８４．９２％,５４．０４％和８２．８１％。食糜和粪中的氨基酸平均消化率分别为８５．９％和７９．５％,两者差异极显著（Ｐ＜０．０１）。加酶组与对照组的淀粉酶、蛋白酶、胰蛋白酶、胰凝乳蛋白酶的活性分别为９２８１．３Ｕ／ｇ和９８９１．５Ｕ／ｇ,３４７．２Ｕ／ｇ和３０４．８Ｕ／ｇ,１０１７．６和７３７．８Ｕ／ｇ,２３．６Ｕ／ｇ和１６．８Ｕ／ｇ。     

家禽营养研究进展及添加剂应用新技术(续)

２饲料添加剂及其应用技术进展２．１饲用酶制剂在肉仔鸡饲料中添加酶制剂的研究比较多。王健鹏等（１９９４）在小型（８１７型）肉鸡饲料中添加３种复合酶各为０．１％,其增重分别比对照组提高了２１．２％、１９．５％和６％,饲料／增重比对照组降低约１１％,另外,胸肌氨基酸总量比对照组增加Ｔ３．３％。林在康等（１９９５）在ＡＡ肉仔鸡饲粮中添加０．１％复合酶,结果发现饲料于物质消化率提高了５９％,有机物消化率提高了５．４％,能量消化率提高了６．６％。陈侠勇等（１９９４）在肉仔鸡饲料中添加０．０２％、０．０５％水…     

尿素精料和碱化秸秆在幼羊全混合日粮中的应用效果

选用 １２ 只两月龄东北细毛公幼羊，按体重大小随机分为 ４ 组，测定不同加工处理全混合日粮（ＴＭ Ｒ）对其生产性能的影响，并分析ＴＭ Ｒ饲养的经济效益。试验结果表明，在含玉米秸的ＴＭＲ 中以尿素精料等氮代替豆饼，在不降低幼羊生产性能的前提下（Ｐ＞ ０．０５），使每千克增重的饲料费用降低２６．４４％ ；在含尿素精料的 ＴＭＲ 中，玉米秸的碱化处理虽未显著影响幼羊的日增重及日采食 ＴＭ Ｒ 量（Ｐ＞ ０．０５），但却使ＴＭＲ 转化率提高了 ２１．５２％ （Ｐ＜ ０．０１），而且每千克增重的饲料费用降低 １１．２５％ ；对含尿素精料及碱化玉米秸的ＴＭＲ 进行颗粒化加工，与加工前相比，试羊日增重、日采食 ＴＭＲ 量及其转化率分别提高了 １６１．９２％ （Ｐ＜ ０．０１）、８８．７４％ （Ｐ＜ ０．０１）及２８．０１％ （Ｐ＜ ０．０１），每千克增重的饲料费用降低１７．６４％ 。     

饲料中添加维生素E对肉种鸡和肉仔鸡生产性能的影响

设４ 个处理组,即在肉种鸡饲粮中添加ＶＥ：０ 、２０ 、３０ 和４０ＩＵ／ｋｇ 。结果表明,饲料中添加ＶＥ 对种蛋受精率、孵化率和肉仔鸡成活率有明显影响（Ｐ＜ ０ ．０５） 。４０ＩＵ 的一组明显高于其它各组（Ｐ＜ ０ ．０５） 。种鸡产蛋率、产蛋量、肉仔鸡日增重、平均日耗料量和料重比不受饲粮ＶＥ添加量的影响（Ｐ＞ ０ ．０５） 。     

海藻作饲料添加剂饲喂产蛋鸡的效果

用６００只产蛋鸡分四组进行了６７ｄ饲养实验,考察海藻粉（ＳＭ）的效果。结果表明：ＳＭ组试鸡产蛋率与商品添加剂组和Ｋ１组比差异显著（Ｐ＜０．０５）,与未加ＳＭ组比差异不显著（Ｐ＞０．０５）。蛋重比其他三组高０．４～１．５ｇ／枚,饲料转化率高６．４％、７．６％和低０．７６％;试期４～２７ｄ,ＳＭ组蛋黄的碘含量由９．４ｕｇ／ｇ增加到６６．８ｕｇ／ｇ（鲜样）。至２７ｄ达到高值,比未加ＳＭ和ＫＩ组高达８．４和５．２倍。蛋白含碘亦由０增加到８．７ｕｇ／ｇ;蛋黄色素变化随着饲养期延长而加深,至２７ｄ达到９个评分等级,比未加ＳＭ和ＫＩ组高２．７和１．５个等级;此外还发现ＳＭ中的碘比ＫＩ中的碘更稳定,两种日粮同时保存５２ｄ,前者损失５９％（碘由８０．４×１０－６降至３２．７×１０－６）,后者损失７６．５４％（碘由８０×１０－６降至１８．７７×１０－６）。     

生长期藏羊蛋白质需要量的研究

采用消化代谢试验、比较屠宰试验、饲养试验、内源尿氮及代谢粪氮测定等方法，研究藏羊生长期氮代谢规律，以测定其蛋白质需要量。研究结果表明，藏羊生长期日粮蛋白质水平以９．０％为宜，高于此值意义不大。用低氮日粮测得藏羊每日排出内源尿氮（ＥＵＮ）为０．１８６ｇ／Ｗ￣０．７５。代谢粪氮（ＭＦＮ）为０．８０９ｇ／Ｗ￣０．７５，氮沉积（ＮＲ）为３．１３ｇ／ｗ￣０．７５。通过对试验数据的统计分析，得出藏羊粗蛋白质维持需要（ＣＰｍ）为８．２８ｇ／Ｗ￣０．７５，日增重需要（ＣＰ△ｇ）为０．４９ｇ／ｇ·△Ｇ）。藏羊生长期的粗蛋白（ＲＣＰ）和可消化粗蛋白质（ＲＤＣＰ）的需要量为：ＲＣＰ（ｇ／ｄ）＝８．２８Ｗ￣０．７５＋０．４９△ＧＲＤＣＰ（ｇ／ｄ）＝６．９１Ｗ￣０．７５＋０．４１△Ｇ     

不同酶制剂对生长猪效果试验

选择１２８头长大二元杂交猪随机分为４组,每组设２个重复。４组分别饲喂含０ｍｇ／ｋｇ、１０００ｍｇ／ｋｇ的红八利酶制剂、万达福酶制剂和溢多利酶制剂的饲粮,试验为期２９天。试验结果表明,猪日粮中添加红八利酶和溢多利酶可促进生长和改善饲料利用率。与对照组相比,红八利酶组平均日增重提高４．９２％（Ｐ＞０．０５）,饲料利用率提高１．７２％（Ｐ＞０．０５）,经济效益提高５．０４％;溢多利酶组平均日增重提高３．８７％（Ｐ＞０．０５）,饲料利用率提高５．５０％（Ｐ＞０．０５）,经济效益提高９．３６％;而万达福酶组对猪的生长性能和饲料利用率有负效应     

抗病促长剂促进肉仔鸡生长发育的试验

用抗病促长剂对肉仔鸡进行促长效果试验，１５日龄时首次肌肉注射抗病促长剂１．０ｍＬ／只，２５日龄时再重复注射２．０ｍＬ／只。在为期３５ｄ的试验中，试验组平均每只鸡增重１９７７．４ｇ，比对照组的１８４０．０ｇ多增重１３７．４ｇ，增重提高了７．４７％，差异极为显著（Ｐ＜０．０１）。     

生长期牦牛蛋白质需要量的研究

将１８头１．５岁生长牦牛分为Ⅰ、Ⅱ、Ⅲ三组，分别饲喂含ＣＰ６．７１％，１０．１４％，１３．４３％的日粮，用比较屠宰试验、消化代谢试验和饲养试验相结合的方法研究其氮代谢。结果表明：Ⅰ、Ⅱ、Ⅲ组日增重分别为５４．０６ｇ，１９３．６７ｇ，２４７．４７ｇ，其中Ⅱ组与Ⅰ组差异显著（Ｐ＜０．０５），Ⅲ组与Ⅰ组差异极显著（Ｐ＜０．０１），而Ⅲ组与Ⅱ组差异不显著（Ｐ＞０．０５）；相应的尿氮（ＵＮ）排出（ｇ／ｄ·Ｗ￣（０．０５２））分别为０．５６２，１．２９１，１．７６２，其中Ⅱ、Ⅲ与Ⅰ差异极显著（Ｐ＜０．０１），Ⅱ与Ⅲ差异显著（Ｐ＜０．０５）；在氮沉积（ＮＲ）、采食氮利用效率方面，三组均无显著差异（Ｐ＞０．０５）。生长牦牛的维持需要量ＲＤＣＰｍ＝６．０９３Ｗ￣（０．５２），增重需要量ＲＤＣＰｇ＝（１．１５４８／△Ｗ＋０．０５０９／Ｗ￣（０．５２））￣（－１）。得出的三个回归方程均呈强直线相关（Ｐ＜０．０１）：１．ＵＮ与进食氮（ＮＩ）的回归方程ＵＮ（ｇ／ｄ）＝－０．１１Ｗ￣（０．５２）＋０．４７３２ＮＩ（ｎ＝９，ｒ＝０．９２８）２．粪氮（ＦＮ）与干物质进食量（ＤＭＩ）及ＮＩ的回归方程ＦＮ（ｇ／ｄ）＝－０．７５１０（１＋０．８     

半胱胺对绵羊消化代谢的影响

十二指肠灌注半胱胺后，４头湖羊平均日采食量（以ＤＭ计）虽无显著性变化，而由复胃进入十二指肠的食糜流量则增加１５．８１％（Ｐ〈０．０５）；食糜ＴＮ流量由１８．３４±０．４２ｇ／ｄ提高到２１．３４±０．５８ｇ／ｄ（Ｐ〈０．０１），其中ＭＣＰ－Ｎ及表观过瘤胃蛋白氮（ＢＰＮ）分别提高２８．５７％（Ｐ〈０．０５）和１４．４４％（Ｐ〈０．０５）。瘤胃液总脱氢酶活力平均提高２１．１５％（Ｐ〈０．０２５），ＮＨ３     

Efficiency of different xylanase preparations in diets for pekin ducks.

Four experiments were conducted with a total of 2288 pekin ducks. Day-old ducklings were group-penned on straw bedding and were fed complete, pelleted diets ad libitum for up to 49 days depending on experiment. In each experiment, starter diets (until day 21) and grower diets (from day 22) were used adequate in ME content and nutrient content. The sum of wheat, rye, and triticale amounted to at least 57% (starter diet) and 63% (grower diet), respectively. The inclusion level of wheat, rye, and triticale was different between experiments, with a maximum rye inclusion of 45%. Five different enzyme preparations all having, 1,4-beta-xylanase as the main activity were considered in this study with either one (2 preparations) or three (3 preparations) levels of supplementation. The effect of enzyme supplementation on ileal digesta viscosity was studied at the end of two experiments comprising 4 enzyme preparations. A significant reduction in digesta viscosity was determined for all preparations. The viscosity of digesta was higher in birds that were fed 45% rye in their diet as compared to those fed a diet based on triticale and wheat, even with enzyme supplementation. Differences in digesta viscosity were not reflected in growth or feed conversion data. In one experiment, the body weight of ducks on day 21 was significantly improved by enzyme supplementation. This effect disappeared with progress in experiment. In another experiment, feed intake was significantly improved with enzyme supplementation. Apart from this, no statistically significant improvement in performance could be detected. On overall average, the final BW of ducks fed an enzyme was (as compared to the unsupplemented control = 100), 100, and the feed conversion ratio was 101. There is no indication from the growth and feed conversion data that an enzyme effect becomes more pronounced with increasing inclusion rate of soluble NSP by rye. It is concluded that supplementary xylanases are efficient in reducing digesta viscosity in ducks fed diets with high inclusion of wheat, rye and triticale. No consistent effect of enzyme supplementation, however, can be expected on growth and feed conversion.     

米曲霉发酵粗酶制剂对肉鸡生产性能和食糜黏度的影响

选择健康、体重一致的1日龄商品代AA肉鸡960只随机分为4组,每组8个重复,每个重复30只,研究分别在玉米-豆粕型日粮和玉米-小麦-豆粕型日粮中添加粗酶制剂对肉鸡生产性能和食糜黏度的影响。结果表明,添加粗酶制剂显著降低了肉鸡的料重比(P<0.05),有提高肉鸡1~42日龄日增重和出栏体重的趋势(P<0.10);在玉米-小麦-豆粕型日粮中添加粗酶制剂可以显著降低肉鸡食糜的黏度(P<0.05)。结果揭示,添加粗酶制剂可以降低肉鸡肠道内食糜的黏度,改善肉鸡的生产性能。     

Effects of diet acidification and xylanase supplementation on performance, nutrient digestibility, duodenal histology and gut microflora of broilers fed wheat based diet

1. The objective of this experiment was to study the influences of xylanase and citric acid on the performance, nutrient digestibility, digesta viscosity, duodenal histology, and gut microflora of broilers fed on a wheat based diet.

2. The experiment was carried out as a 2?×?3 factorial arrangement with two concentrations of xylanase (0 and 200?mg/kg) and three concentrations of citric acid (0, 20 and 40?g/kg). A total of 408 one-day-old chickens with similar body weight were distributed into 24 pens with 17 birds/pen. Each dietary treatment was given to 4 replicate pens from 0 to 24?d of age. To determine the apparent nutrient digestibility, chromic oxide (3?g/kg) was added to the diets as an indigestible marker.

3. Xylanase significantly increased body weight gain at 24?d of age by 1·4% and improved gain-to-feed (G:F) by 3·6%. The inclusion of 40?g/kg citric acid decreased feed intake and body weight gain by 15·4% and 11·8%, respectively. The inclusion of 20?g/kg of citric acid decreased feed intake, but it did not affect body weight gain of broilers at 24?d of age. The inclusion of 20 and 40?g/kg citric acid improved G:F by 3·8 and 4·3% respectively. Xylanase significantly decreased the viscosity of digesta and improved retention of DM, CP, and energy.

4. Xylanase and citric acid did not have any effect on the histo-morphology of the duodenum and intestinal microbial population.

5. In conclusion, citric acid at 20?g/kg decreased feed intake, did not have a negative effect on body weight gain, and improved G:F. Xylanase decreased digesta viscosity, increased nutrient retention and consequently improved performance of broilers fed on a wheat based diet.     

Influence of phytase and xylanase, individually or in combination, on performance, apparent metabolisable energy, digestive tract measurements and gut morphology in broilers fed wheat-based diets containing adequate level of phosphorus

1. The aim of the present study was to examine the influence of microbial phytase and xylanase, individually or in combination, on performance, apparent metabolisable energy, digesta viscosity, digestive tract measurements and gut morphology in broilers fed on wheat-soy diets containing adequate phosphorus (P). The wheat-soy basal diet was formulated to contain 4.5 g/kg non-phytate P and the experimental diets were formulated by supplementing the basal diet with xylanase (1000 xylanase units/kg diet), phytase (500 phytase units/kg diet) or a combination of phytase and xylanase. 2. Supplemental phytase improved the weight gains and feed efficiency by 17.5 and 2.9%, respectively. Corresponding improvements due to the addition of xylanase were 16.5 and 4.9%, respectively. The combination of phytase and xylanase caused no further improvements in broiler performance. 3. Individual additions of xylanase or phytase resulted in numerical improvements in apparent metabolisable energy (AME), but the differences were not significant. The combination of the two enzymes significantly increased AME. Addition of xylanase and the combination of the two enzymes reduced the viscosity of digesta in all sections of the intestine. Phytase supplementation reduced digesta viscosity in the duodenum and ileum, but not in the jejunum. 4. Enzyme supplementation lowered the relative weight and length of the small intestine. Additions of xylanase and phytase reduced the relative weight of the small intestine by 15.5 and 11.4%, respectively, while the corresponding reductions in the relative length of the small intestine were 16.5 and 14.1%, respectively. The combination of phytase and xylanase had no further effects on the relative weight and length of the small intestine compared with the xylanase group. 5. The addition of phytase increased villus height in the duodenum and decreased the number of goblet cells in the jejunum compared with those on the unsupplemented basal diet. Xylanase supplementation tended to increase goblet cell numbers in the duodenum and decreased crypt depth in thejejunum. The combination of phytase and xylanase increased villus height in the ileum and crypt depth in thejejunum and ileum. 6. In summary, the present results showed that the addition of a microbial phytase, produced by solid state fermentation and containing significant activities of beta-glucanase and xylanase, was as effective as xylanase in improving the performance of broiler chickens fed on wheat-based diets containing adequate levels of P. Improved performance with enzyme supplementation was generally associated with reduced digesta viscosity, increased AME, and reduced relative weight and length of small intestine.     

Synergistic effect of cellulase and hemicellulase on nutrient utilization and performance in broilers fed a corn–soybean meal diet

In the present study, the synergistic effect of dietary cellulase and hemicellulase on the nutrient utilization, performance and digesta (content of jejunum) viscosity in broilers fed a corn–soybean meal diet were studied. The treatment groups included a control, cellulase (0.33 U/g feed), hemicellulase (2 U/g feed) and mixed enzyme (cellulase (0.33 U/g feed) + hemicellulase (2 U/g feed)) group. The enzymes were mixed with the basal diet (21.1% crude protein, 3000 kcal/kg metabolizable energy) and fed to male broiler chickens (Cobb strain) for 12 days from 15 days of age. Feed and water were offered ad libitum. Chicks were raised under 25°C in wire‐bottomed cages during the entire experimental period. We found that broilers given enzymes grew faster, and that the mixed enzyme was most effective. Feed intake remained the same for all of the treatment groups. Carcass weight was increased by mixed enzyme significantly, but not by cellulase and hemicellulase. The enzymes, but not mixed enzyme, decreased abdominal fat and were significant in the case of cellulase. Enzymes did not affect muscle weight and nitrogen‐retention, but metabolizable energy content of the diet was improved by the mixed enzyme. Ash‐retention was increased by hemicellulase and mixed enzyme. Digesta viscosity was significantly decreased by cellulase, but not by hemicellulase and the mixed enzyme. The results indicate that the combination of cellulase and hemicellulase has a synergistic effect on the performance of broilers fed a corn–soybean meal diet.     

Effect of enzyme preparation containing xylanase and beta-glucanase on performance of laying hens fed wheat/barley- or maize/soybean meal-based diets

1. A commercial enzyme preparation (Quatrazyme HP) containing xylanase and beta-glucanase was examined in two laying hen experiments with wheat/barley- or maize-based diets. The activities of other enzymes were measured also. Starch, cell wall contents and effects of Quatrazyme HP on in vitro viscosity of wheat, barley, maize and soybean meal were determined. 2. In the first experiment, 90 ISA Brown laying hens at 28 weeks of age were given a wheat/barley basal diet with or without 20mg of Quatrazyme HP, which provided 560 and 2,800 IU of xylanase and beta-glucanase/kg diet. In the second experiment, 66 ISA Brown laying hens at 45 weeks of age were given a maize/soybean meal basal diet with or without 20 mg of Quatrazyme HP/kg diet for 9 weeks. Egg production, egg weight, egg mass, feed conversion ratio and change in body weight were recorded as response criteria. 3. There was a significant improvement in feed conversion ratio with enzyme supplementation. Birds given an enzyme-supplemented diet gained 86 g while those fed on the unsupplemented diet lost 103 g of their body weight by the end of the experiment. 4. The enzyme preparation did not affect either egg production, egg weight or egg mass of birds fed on the maize/soybean meal diet. However, a significant improvement in feed conversion ratio was detected. Birds on either the supplemented or unsupplemented diet exhibited an increase in their body weight at the end of the experiment. 5. Addition of xylanase and beta-glucanase decreased in vitro viscosity of wheat, barley, maize and soybean meal. This effect was greater for wheat and barley than for maize and soybean meal. 6. It was concluded that the beneficial effect of using an enzyme preparation containing xylanase and beta-glucanase is not limited to wheat/barley-based diets but also occurs with maize/soybean meal-based diets.     

Interactions between dietary fat type and xylanase supplementation when rye‐based diets are fed to broiler chickens. 1. physicochemical chyme features

1. The interactions between fat type and xylanase supplementation of rye‐based diets were investigated using a 2 × 2 factorial design in which a rye‐based diet (610 g rye/kg) was combined with 100 g/kg of soya oil or beef tallow, with and without xylanase supplementation at 3000 IU/kg, and fed to 1‐d‐old male broilers. Food passage time, viscosity of digesta supernatant, xylanase activity and pH in different segments of the digestive tract were examined.

2. Food passage throughout the digestive tract was accelerated by enzyme addition regardless of fat type. The time taken for 50% of the marker to be excreted was reduced from 8.4 to 6.7 h in animals receiving the rye‐soya oil diets and from 8.0 to 6.9 h with the rye‐tallow diets.

3. Viscosity in the supernatant of the jejunal and ileal digesta was markedly decreased after enzyme addition. Viscosities were generally higher in the ileal than in the jejunal supernatant, and fell as the birds aged from 14 to 28 d. The effect of enzyme was also reduced in older chicks. There was not a clear effect of the fat source on viscosity.

4. Xylanase activity was still found at the end of the ileum in digesta of birds fed on the enzyme‐supplemented diets but not in control animals. Xylanase activity was also detected in the caeca of all groups.

5. Significantly lower pH values were found in tallow‐fed birds in some segments of the digestive tract. A significant increase in pH after enzyme addition was detected in the proximal ileum; this was independent of fat source.     

Effect of xylanase and beta-glucanase supplementation of wheat- or wheat- and barley-based diets on the performance of male turkeys

The efficiency of a mixture of xylanase and beta-glucanase enzymes was evaluated in two separate experiments on growing turkeys offered diets based on wheat or wheat and barley. 2. In the first experiment, the addition of 560 and 2800 IU of xylanase and beta-glucanase, respectively, per kg of diet significantly improved feed efficiency in turkeys fed on wheat- and barley-based diet throughout the entire experiment (42 d). 3. In the second experiment, the enzyme mixture significantly increased N-corrected apparent metabolisable energy (AMEN) by approximately 5%. 4. Furthermore, the combination of xylanase and beta-glucanase significantly improved body weight gain and feed efficiency. Feed efficiency was increased by 2.94, 2.47 and 5.91% in diets based on 500 then 540 g of wheat/kg of diet, 394 then 384 g of wheat and 100 then 150 g of barley/kg of diet and 180 g of wheat and 300 then 350 g of barley/kg of diet, respectively. 5. This enzyme mixture decreased in vitro viscosity of wheat, barley and soybean meal, the effect being larger for wheat and barley than for soybean meal. 6. In conclusion, the supplementation of diets based on wheat and barley with xylanase and beta-glucanase significantly improved body weight gain and feed efficiency. Therefore, wheat and barley could be used more efficiently by turkeys in the presence of an appropriate enzyme preparation.     

Influence of particle size and xylanase supplementation on the performance, energy utilisation, digestive tract parameters and digesta viscosity of broiler starters

1. The aim of the present experiment was to examine the influence of particle size and xylanase supplementation on the performance, energy utilisation, and gross morphological and histological parameters of the digestive tract of broiler starters fed wheat-based diets. The experimental design was a 2 x 2 factorial arrangement of treatments evaluating two wheat particle sizes (medium and coarse) and two levels of xylanase supplementation (without or with 1000 xylanase units/kg diet). The two particle sizes were achieved by grinding the whole wheat in a hammer mill to pass through 3 and 7 mm screens, respectively. Broiler starter diets, based on wheat and soybean meal, were formulated and each diet was fed ad libitum to 6 pens of 8 male broilers each from d 1 to 21 post-hatch. 2. Wheat particle size had no effect on the performance of broilers. Xylanase supplementation had no effect on weight gain and feed intake. However, a significant particle size x xylanase interaction was observed for feed per unit gain with xylanase lowering feed per gain only in the coarse particle size diet. Xylanase supplementation improved the nitrogen-corrected apparent metabolisable energy at both particle sizes. 3. Xylanase supplementation decreased the relative weight and relative length of all gut components. Villus height and crypt depth and total extent of the mucosal layer were unaffected by both wheat particle size and xylanase supplementation. 4. The apparent viscosity of intestinal digesta, determined over the physiological range of shear rates, was not influenced by xylanase addition or particle size. 5. The findings of this study suggest that the effectiveness of exogenous xylanase in broiler diets is influenced by wheat particle size.     

The incorporation of whole grain into pelleted broiler chicken diets. II. Gastrointestinal and digesta characteristics

1. Pelleted diets, incorporating whole or ground wheat or barley in the pellets, were fed to broiler chickens and the performance, gastrointestinal development and digesta characteristics of those chickens recorded. 2. Body weight was similar with whole grain incorporation or enzyme application. Food conversion efficiency was improved by addition of enzyme to a full wheat diet. 3. Whole grain inclusion in pellets reduced proventriculus proportional mass and increased gizzard proportional mass with no apparent effects of exogenous feed enzyme addition. 4. Relative ileal mass was reduced by enzyme inclusion in a wheat diet and by inclusion of whole barley in the pellets. 5. Digesta viscosity was increased by whole wheat inclusion but reduced by enzyme inclusion irrespective of grain processing. Inclusion of 200 g/kg of barley did not alter viscosity of digesta beyond the duodenum. 6. Fresh excreta pH was higher with both cereals in the grower phase when whole grain was fed. On the barley diet, this was affected by enzyme addition, which created higher pH from a point earlier in the grower phase than when no enzyme was employed. 7. Evidence of a complex interaction between higher viscosity and pH being involved in differences in ileal relative mass was found through significant relationships being produced by enzyme use on the wheat diet alone.