应用离体法和排空强饲法测定鸡饲料代谢能的比较

<正> 近年来,我国在饲料营养价值评定的方法研究方面取得了不少成果。如离体法测定猪的消化能(DE)取代了古典的全粪收集法以及用排空强饲法为主的快速测定法等,在测试手段上比过去有了很大的改进,但其不足之处,仍然是受到试验动物的限制。为了进一步提高其测试效率,1985年我所用中国农科院畜牧所提出的离体法和排空强饲法同时测定了不同质量的糠饼和米糠各15种,两种方法测定的鸡饲料AME值都较接近,作者等认为对鸡的饲料代谢能测定方法的改进有其参考价值。     

鸡饲料代谢能值离体测定法的初步研究

用生物学法和离体法分别对10种肉鸡配合饲料进行了测定,探讨了以离体法干物质消化率或消化能估测鸡配合饲料表现代谢能(AME)值的可行性。并用同步测定的另2种肉鸡配合饲料和5种蛋鸡配合饲料对估测的精度进行了检验。结果表明:10种肉鸡配合饲料的离体法消化能(IVDE)与AME间的相关系数为0.958(P<0.01),回归公式;AME(千卡/克)=1.003IVDE-0.211,残余标准本差Sy,x=土0.055千卡/克。用2种肉鸡饲粮和5种蛋鸡饲粮进行精度检验,AME离体法估测值与生物学法实测值之差最大为0.1千卡/克,说明用离体法消化能可以满意地估测出AME。10种肉鸡饲粮的离体法干物质消化率(IVDMD)与AME间相关系数为0.862(P<0.01),回归公式AME(千卡/克)=0.042IVDMD+0.173,残余标准高差Sy,x=土0.124千卡/克。以此公式估测2种肉鸡饲粮的AME,估测值与实测值最大相差0.1千卡/克,结果令人满意;估测5种蛋鸡饲粮的AME,估测值比实测值大0.16～0.33千卡/克,达不到实用程度。由此可见,如果以IVDMD为自变量估测AMF,对肉鸡饲粮和蛋鸡饲粮有分别建立定标回归方程的必要。     

估测稻谷消化能值的回归方程

通过对三十个稻谷样品常规营养成分、总能、离体消化能值的测定,并用相关、通径和多元回归等统计方法,求得一个用常规营养成分估测稻谷消化能值的最优回归方程:Y=158X_2 84.3X_4-3172.8(R=0.956,N=30,RSD=0.0861)式中:Y 代表稻谷消化能估测值X_2为稻谷中粗脂肪含量,X_4为稻谷无氮浸出物含量.近二十年来,不少学者通过饲料中的化学成分及其可利用能值的关系从不同角度建立过各种数学模型,并报道了各种用以估测饲料消化能(DE)、代谢能(ME)的经验公式.Drennan(1970),Morgan(1975)等先后论证了消化能与粗纤维(CF)之间的相关,并推导出一些回归公式,张子仪(1979)也曾论证了饲料中非营养物质(NNM),如粗纤维或酸性洗涤纤维与其消化能之间的关系;Schcider 及 Harrise(1950,1951)曾通过用饲料中粗蛋白(CP),粗脂肪(EE)、粗纤维和无氮浸出物(NFE)等成分的测定值与各成分的消化率与可消化总氧分(TDN)的关系,求得一多元回归方程以估测猪饲料的消化能,并指出用估测的方法比借用消化率值更为可靠。张子仪等(1983)应用通径方法,通过饲料中粗蛋白、粗脂肪、粗纤维和无氮浸出物等化学成分估测猪饲料的数学模型,并建立了估测能量饲料、蜇白质饲料、粗饲料和青绿饲料的多元回规方程.稻谷是我国主要粮食作物,其产量居世界第一位,1985年稻谷产量达16356.9万吨。据估计1986年约有1685.6万吨稻谷用作饲料,而简易地估测稻谷有效能值是生产中迫切需要的技术之一.本试验试图用离体法测试稻谷中的消化能,即由离体法测值与全粪法消化能测值的相关以及消化能与常规成分之间的相关,求得一个由常规营养成分估测稻谷消化能的最优回归方程.     

家禽饲料有效能值的生物学评定方法

研究畜禽对于饲料及饲料原料的利用情况是传统动物营养学三大基本任务之一,代谢能体系可以很好地表达饲料所含有的有效能值,世界各国在家禽的营养中都应用代谢能体系,但家禽饲料代谢能的评定方法各异。本文综述了家禽饲料有效能值生物学评定方法。     

我国创建猪禽饲料能量生物学效价评定系统

近日,中国农业科学院北京畜牧兽医研究所动物营养学国家重点实验室承担的科技部创新方法工作专项"猪禽饲料能量生物学效价评定方法的创新研究"项目通过验收。饲料有效能值是制定畜禽饲养标准及优化饲料配方的首要技术参数。饲料能量生物学效价的评定是动物营养学科中世界性的"老大难"问题。传统的动物试验法存在着耗时、费力、重演性差的弊端。欧洲及美国、日本等发达国家虽然曾在体外消化技术方面进行过种种尝试,但一直缺     

离体方法在饲料用高粱代谢能值（鸡）评定上的应用

用生物学法和离体法分别对30个饲料用高梁样品进行了测定,以离体法干物质消化率(IVDMD)或离体法消化能(IVDE)为估测因子,对高梁的表现代谢能(AME)的估测可行性进行了探讨,并用15个高粱样品对估测值的精度进行了检验。结果得出:样品IVDE与AME间的相关系数为0.972(P<0.01),残余标准差(RSD)为0.2469 MJ/kg,回归公式为:AME1(MJ/kg)=1.1460+3.5815 IVDE。 IVDMD与AME间的相关系数为0.945(P<0.01),残余标准差(RSD)为0.3473MJ/kg,回归方程为:AME2(MJ/kg)=0.8033+0.1435 IVDMD。精度检验结果,估测值与实测值都才目当接近(P>0.05)。 试用公式1对大麦(江苏农学院提供)、稻谷(湖南农学院提供)、小麦、米糠(湖南省畜牧兽医所提供)等能量饲料的AME进行估测,前两样估测值与实测值比较近似(P>0.05),而后两样的估测值与实测值则差异较大(P<0.01)。试用估测肉鸡或蛋鸡配合饲料的AME的回归公式估测高梁,估测值与实测值差异均较大。     

国内创建猪禽饲料能量生物学效价评定系统

<正>近日,中国农业科学院北京畜牧兽医研究所动物营养学国家重点实验室承担的科技部创新方法工作专项"猪禽饲料能量生物学效价评定方法的创新研究"项目通过验收。饲料有效能值是制定畜禽饲养标准及优化饲料配方的首要技术参数。饲料能量生物学效价的评定是动物营养学科中世界性的"老大难"问题。传统的动物试验法存在着耗时、费力、重     

近红外快速预测饲料原料有效能值及其影响因素

饲料有效能值（Bioavail Eenrgy，BE）评定历来是饲料营养价值评定中一个极其重要的内容，寻找快速、简便、实用的评定饲料有效能的方法是营养学家追求的目标。     

猪禽饲料能量生物学效价评定系统创建

<正>近日,中国农业科学院北京畜牧兽医研究所动物营养学国家重点实验室承担的科技部创新方法工作专项"猪禽饲料能量生物学效价评定方法的创新研究"项目通过验收。饲料有效能值是制定畜禽饲养标准及优化饲料配方的首要技术参数。饲料能量生物学效价的评定是动物营养学科中世界性的"老大难"问题。传统的动物试验法存在着耗时、费     

家禽饲料有效能值的测定及影响因素

<正>客观准确地评定饲料原料和饲料的有效能值是开发利用饲料资源及优化饲料配方的主要决策依据。实践中,为了经济地配制家禽日粮,就要准确地测定各种饲料原料中(尤其是能量饲料)的有效能值,低估了能值,就会在最低成本日粮中拒用一种成分,但     

Analyses of degradation products from lipid and protein hydrolyses in the small intestine of broiler chickens fed on maize-based diets containing guar gum,or wheat-based diets

1. Three maize diets containing graded levels (0, 0.1, 0.3%) of guar gum and two wheat diets differing in their in vitro viscosities were fed to male broiler chickens (7 to 23 d) for measurements of growth performance and analyses of degradation products from lipid and protein hydrolyses in the small intestine of broiler chickens. Analyses of degradation products were conducted to define which step (hydrolysis or absorption) was most involved in the negative effects of the digesta viscosity on lipid and protein digestibilities. The experiment was also carried out to examine whether effects of wheats could be explained in terms of intestinal viscosity alone. 2. The intestinal viscosities with wheat diets were within the range of those observed with the three maize diets. The correlations between in vivo and in vitro viscosities were higher with real than with potential applied viscosity of diets, both in jejunum and ileum. 3. The mean gain:food ratio observed with wheat diets was lower (P<0.05) than with maize diets despite lower (P<0.05) mean intestinal viscosities in birds given the wheat than given the maize diets. This shows that factors different from intestinal viscosity were also involved in the negative effects of wheats. 4. Distributions of nitrogen compounds in digesta were characterised by low proportions of compounds with high molecular weight (>12,000). For all classes of nitrogen compounds, the contents measured in digesta dry matter did not differ between chickens fed with or without guar gum. 5. Distributions of lipid classes in both jejunum and ileum were characterised by a large proportion of free fatty acids (FFA) and very few triglycerides (TG). In the ileum, FFA and TG contents were both positively correlated with supernatant viscosity, but the slope for FFA content was 35 times higher than for TG. In these relationships, there was no difference between maize and wheat diets. 6. It is concluded that absorption was the main step involved in the lipid digestibility reduction due to intestinal viscosity. For proteins, the most important step (hydrolysis or absorption) involved in decreased digestibility due to intestinal viscosity was not clearly identified.     

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.     

Chemical composition and the nutritive quality of different wheat cultivars for broiler chickens

1. Different wheat cultivar samples were grown in replicated trials on a single site in three harvest years. A total of 23 wheat samples were harvested. Nutritionally complete, meal-form diets that included each wheat sample at 650 g/kg were used to compare broiler growth performance and determine apparent metabolisable energy (AME). The relationships were examined between these variables of nutritive value for broilers and the chemical composition and tests of quality on the wheat samples. 2. The total starch contents of the wheat samples ranged from 594 to 732 g/kg dry matter (DM). The mean total non-starch polysaccharide (NSP) content was 100g/kg DM comprising 73.5 g/kg DM of insoluble material. Endosperm hardness ranged between 10 and 77 relative units and Beaver was the softest cultivar in two of the batches of samples. The AME of the wheat-based diets had a maximum range of 0.5 MJ/kg within each of the three batches of wheat that were tested. 3. Endosperm hardness of the wheat grains, within a harvest year, was positively correlated with broiler weight gain and the 1000-grain weight was negatively correlated with feed conversion efficiency (FCE). Starch content and gross energy were positively correlated with determined AME, and DM, 1000-grain weight and water holding capacity were negatively correlated with AME. 4. A step-wise regression technique indicated that endosperm hardness and ash content of the wheat were the explanatory variables that, within harvest years, significantly reduced the unexplained variation in broiler growth rate, feed intake and FCE. The contents of total starch, crude protein and ether extract were the explanatory variables that, within harvest years, significantly reduced the unexplained variation in AME.     

The dietary effect of different wheat cultivars for broiler chickens.

1. An experiment was conducted to examine the variability in chemical composition of 16 wheat cultivars and to study how this variability affected the performance of broiler chickens given diets containing 650 or 815 g wheat/kg diet during the first 3 weeks of life. Intestinal viscosity, apparent fat digestibility and apparent metabolisable energy were determined with all diets. Intestinal pH and the relative weight of different parts of the intestine were measured in chickens fed on diets with the high wheat inclusion. 2. The 16 wheat cultivars varied in chemical composition, with protein content ranging from 112 to 127 g/kg dry matter, starch content from 658 to 722 g/kg dry matter and non-starch polysaccharides from 98 to 117 g/kg dry matter. The effect of the different wheat cultivars on the measured parameters was most pronounced in chickens fed on diets with 815 g wheat/kg diet (P<0.001). However, significant (P<0.001) differences between cultivars were still present at the lower wheat content. 3. Milling-quality wheats resulted in better performance (P<0.001) than feeding-quality wheats at the high inclusion, whereas such an effect could not be registered in diets at the lower wheat inclusion. These results indicate that some of the feeding wheats are comparable in quality to milling wheats when included at the concentrations which are more common in practical broiler diets. 4. Decreasing the wheat content in the diets resulted in significantly (P<0.001) better performance and considerably (P<0.001) lower intestinal viscosity (jejunum; 2.4 to 5.9 cps, ileum; 4.6 to 10.9 cps) than in chickens fed on diets with the higher wheat inclusion level (jejunum; 9.1 to 38.4 cps, ileum; 20.8 to 82.0 cps). 5. Diets with 815 g wheat/kg influenced pH in the caeca, but not in the ileum and gizzard. The relative weights of the gizzard and ileum differed significantly (P<0.05) between treatments, whereas those of duodenum, jejunum and caeca were not affected by dietary addition of the different wheat cultivars. 6. The present study demonstrated that the chemical composition and the nutritive value of Danish wheats for broilers vary markedly. The results indicated that the non-starch polysaccharide and especially the arabinoxylan content of wheat are important factors in the discussion of the result obtained. Poor correlations were seen between performance and AMEn and care should be taken when using AMEn values alone to predict the nutritive value of wheat and wheat-based diets.     

Nutrient digestibility and intestinal viscosities in broiler chickens fed on wheat diets, as compared to maize diets with added guar gum

1. Three maize diets containing 0, 1 or 3 g of guar gum per kg and 2 wheat diets were given to male broiler chickens for measurements of growth performance and nutrient digestibility. 2. The intestinal viscosities found with wheat diets were within the range of those observed with the 3 maize diets. The correlations between in vivo and in vitro viscosities were higher with real than with potential applied viscosity. 3. The gain:food ratio decreased (P < 0.05) with the addition of 3 g guar gum/kg. The mean gain:food ratio observed for wheat diets was lower (P = 0.007) than the mean value found for the 3 maize diets. 4. The negative effects of increased intestinal viscosity due to guar gum addition on nutrient digestibility were highest for lipids and lowest for starch. 5. Wheat diets resulted in much lower (P < 0.001) starch apparent digestibility compared to maize diets with added guar gum despite similar mean intestinal viscosities in the 2 groups of diets. Apparent lipid digestibility with wheat diets was lower (P < 0.01) than the value predicted from intestinal viscosity, the predictive model having been calculated with the guar gum added maize diets. Apparent protein digestibility did not differ between wheat diets and guar gum added maize diets. 6. It was concluded that the low apparent digestibilities of starch and lipid observed with wheats could not be attributed only to intestinal viscosity and that other factors appear to be implicated in the low digestibilities observed with the wheat samples tested in the present experiment.     

Soft wheat instead of hard wheat in pelleted diets results in high starch digestibility in broiler chickens

(1) The aim of the experiment was to re-examine variations in digestibilities of food components in 3-week-old broiler chickens fed on pelleted diets based on wheats differing in lipase activity and hardness. Fourteen wheat (Triticum aestivum) samples, each from a different cultivar, were included at 550 g/kg in 14 different diets given to male Ross broiler chicks from 7 d of age. The other main ingredients consisted of soyabean meal (353 g/kg) and rapeseed oil (55 g/kg). A 15th diet containing durum wheat (Triticum durum) was also tested. (2) Hardness of wheats (Triticum aestivum) varied between 14 (very soft) and 88 (very hard), and lipase activity of wheats varied from 1 to 13.1 (relative scale). No significant correlation was found between in vitro viscosities and other parameters such as hardness, particle size of wheat flours and lipase. Hardness was correlated with the mean particle size of wheat flours and durability of pellets. (3) Individual lipid digestibilities were negatively correlated with in vitro viscosities of wheats. (4) Individual starch digestibilities were negatively correlated with wheat hardness, particle size of wheat flour before pelleting, and pellet durability. The ratio of measured AME(N) to predicted AME(N) was also negatively correlated with wheat hardness. Simple regression calculation showed that a 100-point increase in wheat hardness resulted in a 3% decrease in the AME(N) value of diets. Multiple regression calculation showed the food/gain ratio (d 10 to d 21) to be positively related to wheat hardness and negatively related to pellet durability. (5) Wheat lipase activity was positively correlated with individual starch digestibility, which was the reverse of a result obtained in a previous experiment. Thus, wheat lipase activity did not seem consistent for predicting starch digestibility and AME(N) values. (6) Among all wheat samples, durum wheat showed the highest protein content and the lowest content of water-insoluble cell-wall. Starch digestibility of durum wheat tended to be lower than that of other wheats (0.916 vs 0.936). However, no significant difference in AME(N) was observed between the durum wheat sample and other wheats. (7) Gut morphometric data measured at d 24 did not show significant differences between dietary treatments.     

In vitro bile acid-binding capacity of dietary fibre sources and their effects with bile acid on broiler chicken performance and lipid digestibility

1. A 4 × 2 factorial experiment was conducted to study the effect of feeding diets-containing dietary fibre (DF) sources and a source of bile acid (BA) on growth performance and lipid metabolism. In addition, in vitro BA-binding capacity of fibre sources was investigated.

2. A total of 256 one-d-old male broiler chickens (Ross 308) were assigned to DF sources [maize-soybean meal (control, C), or 30 g/kg of wheat bran (WB), barley bran (BB) or soybean hulls (SH)] and BA (with or without 1.5 g Na-deoxycholate/kg). Each treatment was replicated 4 times with 8 broiler chickens per cage.

3. The highest in vitro BA-binding capacity was observed with BB (8.76 mg/g BB). From 0 to 21 d, with the addition of BA, the average daily feed intake (ADFI) decreased in broiler chickens fed on the C, WB or BB diets, while there was no difference with the SH diet. With added BA, the average daily gain decreased in broiler chickens fed on the C or SH diets, but it did not change in those fed on the other diets. The addition of BA decreased feed conversion ratio (FCR) in broiler chickens fed on the BB or WB diets, but it increased in those fed on the C or SH diets. Interaction results indicated that the apparent ileal digestibility of lipid increased in broiler chickens fed the C and other DF diets with BA compared to those fed the diets without BA. The addition of BA decreased the pancreas lipase activity (PLA) in broiler chickens fed on the C diet compared to those fed the C diet without BA, while no changes observed in those fed the DF diets with or without BA. No interaction was observed in total liver bile acid (TLBA).

4. The WB, BB and SH with little Na-deoxycholate-binding capacity (<10 mg/g of DF) under in vitro conditions had particular effects with BA on the measured criteria in broiler chickens. The magnitude of improvement in digestibility of lipid with the addition of BA depends on the source of fibre used and the addition of BA in DF diets had little effect on growth performance in young broiler chicken diets.

     

肉仔鸡体外消化模拟技术评定不同剂量植酸酶作用效果的研究

对肉仔鸡体外消化模拟技术评定不同剂量植酸酶在玉米-豆粕日粮中作用效果的可行性进行了检验.在体外条件下,分别测定了添加与不添加植酸酶的6种玉米-豆粕日粮磷体外消化率和无机磷释放量.结果表明：磷体外消化率和无机磷释放量随植酸酶添加水平的增加而增加（P＜0.01）,添加不同剂量的植酸酶日粮,磷体外消化率和无机磷释放量与肉仔鸡日增重、采食量、回肠磷消化率、胫骨灰分和磷的沉积以及胫骨灰分中磷的含量等指标均存在强相关（R^2=0.971,0.990,0.962,0.903,0.866,0.986和R^2=0.970,0.987,0.976,0.898,0.859,0.984）.利用肉仔鸡体外消化模拟技术,可以评定和预测玉米-豆粕日粮中添加不同剂量植酸酶对肉仔鸡生产性能和磷利用的影响.     

The incorporation of whole grain into pelleted broiler chicken diets: production and physiological responses

1. Pelleted diets, incorporating whole or ground triticale or wheat in the pellets, were fed to broiler chickens and the performance, gastro-intestinal development and health of those chickens recorded. 2. The use of whole triticale in the pelleted food produced similar bodyweight responses to when ground triticale was incorporated in the food. Food conversion efficiency was enhanced when whole triticale was used compared to ground triticale and was similar to when an exogenous enzyme was added to the ground triticale diet. The incorporation of whole wheat into the pelleted food produced similar production responses to the use of ground wheat. 3. The gastro-intestinal development of the birds was greater when they were fed the whole grain diet as gizzard weights were increased by the incorporation of whole grain into the diet. Gastro-intestinal development was thought to be related to the presence of large fibre particles in the food. 4. Proventricular dilatation and mortality due to ascites were reduced by feeding pelleted diets containing whole grain, which was possibly related to the early development of the gastro-intestinal tract relative to total body development. 5. It is suggested that the current use of exogenous enzyme additions to broiler diets may be reduced by incorporating whole grain into pelleted diets for broiler chickens.     

Ileal starch digestibility in growing broiler chickens fed on a wheat-based diet is improved by mash feeding, dilution with cellulose or whole wheat inclusion.

1. An experiment was conducted to study causes of low ileal starch digestibilities when broiler chickens were fed on wheat-based diets. Each of 5 cold-pelleted diets containing 771 g/kg DM wheat and one cold-pelleted diet containing 694 g/kg DM wheat were fed to 24 male broiler chickens in 8 cages from 10 to 21 d of age. 2. Feed intake and weight gain were significantly reduced when the wheat diet was crushed and fed in a mash form. 3. Ileal starch digestibility increased significantly from 0.79 to 0.95, 0.93 and 0.91, respectively, when the diet was crushed and fed in a mash form, was diluted with cellulose prior to pelleting, or when parts of the wheat were fed as whole grains. Correspondingly, random variation between individual birds was reduced. 4. These results indicate that an overload of wheat starch in the digestive tract may be the cause of poor digestibility for some broilers in a flock. Grinding of the wheat may also influence starch digestibility.