Real ileal protein and amino acid digestibilities in feedstuffs for growing pigs as determined with the 15N-isotope dilution technique

Twelve gilts, with an average initial BW of 38 kg, were fitted with a simple T-cannula at the distal ileum and two catheters in the external jugular veins. The animals were fed 700 g of one of the experimental diets, twice daily at 0800 and 2000. Diets 1 and 2 were cornstarch-based diets formulated to contain 16% CP from soybean meal and canola meal, respectively. Diets 3 and 4 contained 93.9% wheat and barley, respectively. Chromic oxide was included to determine nutrient digestibilities. Following recovery from surgery, 15N-leucine was infused continuously via a jugular catheter for 9 d at a rate of 40 mg.kg BW-1.d-1. Blood samples were taken at every feeding. Ileal digesta were collected for 24 h on d 7 and 9 of the infusion period. Assuming that the 15N-enrichment excess in the trichloroacetic acid-soluble fraction of the blood was similar to that in endogenous N, the contribution of endogenous to total N in ileal digesta was calculated. The amount of endogenous protein (N x 6.25) recovered in digesta collected from the distal ileum were 25.5, 30.5, 27.4 and 27.7 g/kg DM intake for the pigs fed diets 1, 2, 3 and 4, respectively. In the same order for the diets, the real ileal protein digestibilities were 97.5, 84.1, 99.0 and 94.2%, respectively. In addition, the real ileal amino acid digestibilities were calculated. The recoveries of endogenous protein in ileal digesta and the real ileal protein and amino acid digestibilities were higher than those determined by feeding protein-free diets for determining the recovery of endogenous protein and amino acids in ileal digesta.     

水果蔬菜和鱼类的副产物作为猪饲料的可行性分析

我们对水果蔬菜和鱼类的副产物作为育肥猪的饲料进行了可行性分析。这些副产物主要是指水果蔬菜的皮、核以及鱼内脏等，主要来自于西班牙的Salamanca的商店，并且对它们的营养成分、矿物质含量以及可消化性进行了评估。在本次实验中，这些副产品的干物质含量偏低（在果菜和鱼类副产物分别为12％和26％），但这些干物质却包含了所有猪饮食中所需的营养成分。鱼类的副产物含有58％的粗蛋白、22％的灰份、19％的醚提取物和1％的粗纤维，而果菜副产物中含有65％自由氦提取物、13％粗纤维、12％粗蛋白、8％的灰份以及2％醚提取物。这些副产物随着温度的升高，它们的可消化性会逐渐降低，所以温度高于65℃的果菜副产物和高于105℃的鱼类副产物，我们都予以废弃，这也是出于控制微生物含量的考虑。     

Effect of fumaric acid and dietary buffering capacity on ileal and fecal amino acid digestibilities in early-weaned pigs

Experiments were conducted to determine the effect of fumaric acid supplementation and buffering capacity of the diet on ileal and fecal digestibilities of CP, GE, and amino acids in early-weaned pigs. In two experiments, 12 pigs each were weaned at 14 d of age and fitted with a simple T-cannula at the distal ileum between 15 and 17 d of age. In both experiments, the pigs were fed four diets, based on wheat and soybean meal without (control) or with 1, 2, or 3% fumaric acid according to a balanced two-period change-over design. In Exp. 2, the buffering capacity of the diets was increased by supplementation of 3% sodium bicarbonate. The pigs were fed three times daily: equal amounts at 8-h intervals. The diets were supplied at a rate of 5% (wt/wt) of body weight. The inclusion of fumaric acid to the diet with a low buffering capacity increased (P < .05) the ileal digestibilities of CP, GE, and the majority of amino acids. The highest responses were found at an inclusion level of 2% fumaric acid. The improvements in apparent ileal amino acid digestibilities ranged from 4.9 to 12.8 percentage units. Supplementation of fumaric acid to a diet with a high buffering capacity led only to numerical increases in ileal digestibilities of CP, GE, and amino acids. In both studies, fumaric acid supplementation had no effect (P > .05) on the fecal digestibilities of CP, GE, and amino acids, except histidine. A high buffering capacity of the diet decreased the ileal amino acid digestibilities by 1 to 10 percentage units compared with diets with the low buffering capacities. In both experiments, ileal and fecal digestibilities were higher (P < .05) in Period 2 (on d 24 after weaning) than in Period 1 (on d 11 after weaning). A positive correlation (P < .05) between ileal digestibilities and fumaric acid supplementation to the diets with the low buffering capacities was observed in Period 1 (on d 11 after weaning), but not in Period 2 (on d 24 after weaning). No relationship (P > .05) between ileal digestibilities and fumaric acid supplementation to the diets with a high buffering capacity could be established. In conclusion, supplementation of fumaric acid to starter diets during the first 3 to 4 wk after weaning increases the ileal digestibilities of GE, CP, and amino acids.     

饲料回肠末端氨基酸消化率测定方法的研究

畜禽饲料回肠消化率是一项评评价饲料营养价值更有效的指标，和以配制日粮，更符合畜禽对营养物质的需要，饲料因种类，来源及加工处理不同，回肠消化率也表现出差异；同时饲料回肠消化率又受动物年龄，性别、生长阶段及生产目的影响。     

Prediction of protein and amino acid composition and digestibility in individual feedstuffs and mixed diets for pigs using near-infrared spectroscopy

Knowledge of the amounts and digestibility of amino acids in pig feedstuffs is essential for calculating the appropriate inclusion level in a complete diet. Wet chemical analysis and in vivo digestibility trials are time-consuming and costly and cannot be used for routine assessment. Near-infrared spectroscopy (NIRS) offers a rapid, cost effective and environmentally friendly method for evaluating feedstuffs. Calibrations models were developed using NIRS to predict the content of crude protein and 18 amino acids from a wide range of feedstuffs used in pig production (n = 607). The samples ranged from single feed ingredients (containing amino acids from 0.3 to 129.8 g/kg of dry matter) to feed mixtures (containing amino acids from 1.2 to 53.2 g/kg of dry matter). The predictive ability of the calibrations was tested with an independent dataset (n = 150) and with cross-validation. Furthermore, we compare these calibrations with calibrations developed on more narrowly defined groups of samples and with predictions from regression analysis of crude protein. The models were able to predict the concentrations of crude protein and 18 amino acids with good levels of precision and high coefficients of determination for calibration (RSQ ^CAL) from 0.91 to 0.99 and validation (RSQ^VAL) from 0.87 to 0.97. Calibration models were able to predict all amino acids except tryptophan and valine with greater accuracy than those from protein regression. We also developed calibration models to predict the apparent ileal and total tract digestibility of protein and amino acids. With the exception of tryptophan, RSQ values (>0.7) and standard error of cross validation (SECV) values (<5%) were obtained for the digestibility of most of the amino acids. In conclusion, NIRS can be used to predict crude protein and amino acid concentrations from a wide range of single ingredients and feed mixtures used for pig diets without separate models for each feedstuff. The digestibility of protein and amino acids can be predicted with an acceptable accuracy to be useful in formulating pig diets.     

Effect of phytase supplementation to diets for weanling pigs on the digestibilities of crude protein, amino acids, and energy

Four experiments were conducted with weanling pigs fitted with a simple T-cannula at the distal ileum, to determine the effect of phytase supplementation to four diets on the apparent ileal digestibilities (AID) of CP and AA, and the apparent total-tract digestibilities (ATTD) of CP and DE. Phytase (Natuphos, DSM Food Specialties, Delft, The Netherlands) was supplemented at rates of 0, 500 or 1,000 FTU/kg to the four diets. A 20% CP (as-fed basis) corn-soybean meal diet was used in Exp. 1; a 20% CP wheat-soybean meal diet in Exp. 2; a 20% CP wheat-soybean meal-canola meal diet in Exp. 3; and a 19% CP barley-peas-canola meal diet in Exp. 4. In each experiment, six barrows, fitted with a simple T-cannula at the distal ileum, were fed the basal plus phytase-supplemented diets according to a repeated 3 x 3 Latin square design. Each experimental period comprised 14 d. The piglets were at fed 0800 and 2000 daily, equal amounts for each meal, at a daily rate of at least 2.4 times the maintenance requirement for ME. Feces were collected from 0800 on d 8 until 0800 on d 12 of each experimental period. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Chromic oxide was used as the digestibility marker. The average initial and final BW (average of all experiments) were 7.9 and 16.5 kg, respectively. Phytase supplementation did not improve the AID of CP and AA in Exp. 1, 2, and 4; however, there were improvements (P < 0.05) or tendencies (P < 0.10) toward improvements in the AID of CP and AA or the ATTD of CP and the content of DE with phytase supplementation in Exp. 3. These results suggest that the AA response factor to microbial phytase supplementation depends on diet composition.     

以可利用氨基酸配制肉鸡饲粮研究

降低畜牧业生产对环境所造成的负面影响,最有效的技术在于降低氮摄入量和保持氨基酸的平衡供给以满足动物的需要.因此,以可利用氨基酸指标按理想蛋白质模式给畜禽配合日粮,可以更准确地满足需要,提高蛋白质的转化效率,节省蛋白质饲料资源,减少粪氮的排出.为此,我们进行了以可利用氨基酸配制肉鸡饲粮的研究.     

Comparative protein and amino acid digestibilities in growing pigs and sows.

An experiment was conducted to compare apparent total tract protein digestibilities and apparent ileal digestibilities of protein and amino acids in growing pigs and adult pregnant and lactating sows. Twelve growing pigs and 12 sows were used and surgically fitted with simple T-cannulas at the distal ileum. Six experimental diets based on corn, barley, wheat, soybean meal, canola meal, or meat and bone meal were formulated, and each diet was fed to growing pigs, gestating sows, and lactating sows for 7 d. Chromium oxide was included in all diets as an indigestible marker (.25%) for calculating nutrient digestibilities. Fecal material was collected on d 5 of each feeding period by grab sampling, and ileal samples were collected for 12 h/d during the last 2 d of each feeding period. Apparent fecal protein digestibilities for all feed ingredients were higher (P < .05) in gestating and lactating sows compared to growing pigs, but no differences between the two groups of sows were observed (P > .05). At the distal ileum, no differences (P > .05) in protein digestibilities were detected between sows and growing pigs regardless of feed ingredient. For all feed ingredients tested, lactating sows had apparent ileal digestibilities of most amino acids that were two to six percentage units higher than those obtained in growing pigs, but not all of the differences were significant. Gestating sows had digestibilities of most amino acids that were intermediate between those of growing pigs and lactating sows. The combined results from the six feed ingredients showed that lactating sows had higher (P < .05) digestibilities of all indispensable amino acids except arginine, and gestating sows had higher (P < .05) digestibilities of five of the indispensable amino acids than did growing pigs. The results of this experiment indicate that apparent fecal protein and apparent ileal amino acid digestibilities obtained in growing pigs are not always representative of digestibilities in either gestating or lactating sows.     

五种蛋白质饲料的家禽氨基酸利用率测定研究

以可利用氨基酸为基础配制动物日粮已成为发展趋势。因此,饲料原料的可利用氨基酸含量和氨基酸利用率的测定是非常重要的。目前,国内动物日粮配制所参照的营养需要量标准和饲料氨基酸利用率大都依据国外的数据。国内的饲料原料因生长环境、气候、土质及饲料原料品种等与国外不同,两者营养成分含量差异较大,其氨基酸利用率差异也较大。为尽快建立起国内主要饲料原料的养分含量和氨基酸利用率数据库,为饲料营养价值的评定和配制动物日粮时选取饲料原料提供参考依据,本试验用正常鸡测定了鱼粉、大豆粕、菜籽粕、花生粕和棉籽粕5种饲料原料的氨基酸表观和真利用率。     

植酸酶对不同类型的断乳仔猪日粮粗蛋白、氨基酸和能量的消化率的影响

通过对4个安装了简易T型瘘管的断奶仔猪研究表明,添加植酸酶并没有提高玉米-豆粕型日粮(试验组1)、小麦-豆粕型日粮(试验组2)和大麦-豌豆-菜籽粕型日粮(试验组4)粗蛋白和氨基酸的回肠表观消化率(AID),而使小麦-豆粕-菜粕型日粮的粗蛋白和氨基酸回肠表观消化率或粗蛋白和消化能的总消化道表观消化率(ATTD)得到了显著的提高(P<0.05)或呈提高的势态(P<0.10)。这些结果表明,氨基酸对细菌性植酸酶的反应因子取决于日粮的组成。     

植酸酶在含有玉米副产品猪日粮中的效果

因为即使是不添加微生物型植酸酶,干酒糟副产品中的磷也可被猪充分地消化,所以添加植酸酶对提高这些成分中磷的消化率仅能产生极为有限的作用,因此并不经济。     

Efficiency of amino acid utilization in the growing pig at suboptimal levels of intake: lysine, threonine, sulphur amino acids and tryptophan

A series of N balance experiments using growing pigs was conducted to study the efficiency of utilization of lysine, threonine, sulphur amino acids and tryptophan and to estimate their maintenance requirements. Purified diets based on casein and crystalline amino acids as the sole source of N contained graded levels of each amino acid, corresponding to expected protein accretion rate of 0, 33, 66, 99 and 132 g/day, respectively. N retention increased linearly (p < 0.01) as the dietary concentration of the limiting amino acid increased. Based on linear regression equations relating amino acid deposition in body protein to amino acid intake, marginal efficiencies of ileal digestible amino acid utilization were calculated to be lysine 0.91, threonine 0.83, sulphur amino acids 0.85 and tryptophan 0.66. Extrapolating the regression equations to zero N retention, the daily requirements of amino acids for N equilibrium were estimated to be (mg/kg(0.75)) lysine 39, threonine 49, sulphur amino acids 46 and tryptophan 16.     

The effect of microbial phytase on true and apparent ileal amino acid digestibilities in growing-finishing pigs

Ten 56-d-old, 15-kg barrows were surgically fitted with a postvalvular T-cecum cannula at the ileo-cecal junction to evaluate the effect of microbial phytase on apparent and true ileal AA digestibility and N utilization. A semipurified cornstarch- and soybean meal-based diet was formulated to contain 3.4 Mcal of DE/kg, 17.0% CP, 0.8% Ca, and 0.6% P but had a low phytate-P concentration (0.13%; all on an as-fed basis). Chromic oxide and dysprosium chloride were used as indigestible markers. The basal diet was supplemented with 0 or 1,000 phytase units/kg of microbial phytase. Postprandial plasma urea N and alpha-amino N concentrations, excretion of Ca, P, and N in feces and urine, and ileal AA digestibilities were determined 3 times at 4-wk intervals beginning at 70 d of age. The homoarginine (HA) method was used to determine endogenous AA flow by replacing 50% of the basal protein with guanidinated protein. Microbial phytase had no effect on apparent ileal digestibility (AID) or on true ileal digestibilities of N and most AA but did increase AID for arginine (P = 0.006) and methionine (P = 0.037). However, in HA diets, phytase increased the AID of CP (P = 0.01) and several AA. Addition of microbial phytase had no effect on the postprandial alpha-amino N concentrations in plasma but increased overall plasma urea N concentrations (P = 0.035). Barrows fed phytase-supplemented diets had decreased P in feces (P = 0.003) and greater P in urine (P = 0.001) but comparable total P excretion compared with barrows fed no phytase-supplemented diets. In conclusion, the addition of phytase to a semi-purified soybean meal-based diet did not affect the AID of several AA. In addition, differences between the basal and HA diets in N digestibilities indicated that that guanidination may limit the use of the HA method in determining endogenous protein losses.     

The influence of caecectomy on amino acid availability of three feedstuffs for ganders

1. Experiments were conducted to assess the influence of caecectomy on amino acid availability (AAA) of three feedstuffs for goose. 2. Nine caecectomised and 9 intact Yangzhou ganders, 24 weeks old, were used in these experiments. Fish meal, soybean meal and cottonseed meal were used as the sole source of protein. The endogenous amino acid (AA) losses were evaluated by a nitrogen (N)-free diet method. The influence of caecectomy on apparent amino acid availability (AAAA) in fish meal, soybean meal and cottonseed meal was assessed in experiment 1 and true amino acid availability (TAAA) of three protein diets was determined in experiment 2. 3. Results showed that, in the soybean meal and cottonseed meal, the AAAA and TAAA of most AA determined by the intact ganders were higher than in the caecectomised ganders; in the fish meal, the AAAA and TAAA of most AA determined by the intact ganders were lower than in the caecectomised ganders. 4. Results of the present study suggest that the effect of caecectomy on AAA in geese was dependent on the feedstuff assayed, and it was better to use caecectomised poultry for AAA assessment.     

Steroid hormone pathways in the pig, with special emphasis on boar odor: a review

Although castration of male pigs grown for meat production has long been a commercial practice in order to eliminate an undesirable odor emanating from the meat upon heating, intact males (boars) grow faster, utilize feed more efficiently and produce leaner carcasses. This review outlines the biochemical pathways of steroid hormone formation in the pig, placing special emphasis on the C19-delta 16-steroids, which have been shown to produce the "urine- or perspiration-like" odor of boar meat. Analytical methods currently available for quantitation of the C19-delta 16-steroids are also reviewed, including gas chromatography-mass spectrometry, radioimmunoassays and enzyme-linked-immuno-absorbent-assays (ELISA). Finally, methods for preventing boar odor are discussed, such as environmental methods of rearing boars, genetic selection against boar odor and autoimmunization against C19-delta 16-steroids. Autoimmunization techniques appear to offer the most promise for inhibiting production of the compounds responsible for boar odor in male pigs raised for meat production, while still maintaining the advantages of improved efficiency and greater leanness.     

生长猪回肠氨基酸消化率的标准化测定方法

根据荷兰CVB(1996)和德国GfE(2002、2005)的最新规定,提出了生长猪回肠氨基酸消化率测定的一个标准化方法。本文从①试验动物、猪舍环境和饲喂条件,②消化糜的收集及处理,③回肠氨基酸消化率测定方法三个方面比较了这些规定之间的差异和相似性。     

Standardization of methods for the determination of ileal amino acid digestibilities in growing pigs

Based on current recommendations of the CVB (1996) in the Netherlands and the GfE (2002, 2005) in Germany, a standardization of methods for the determination of ileal amino acid digestibilities in growing pigs is proposed. Differences and similarities between these protocols in terms of (i) animals, housing and feeding conditions (ii), methods for digesta collection and handling, and (iii) approaches to determine ileal amino acid digestibilities are described.     

玉米-豆粕型日粮中添加复合酶对仔猪生长性能及养分消化率的影响

选用72头胎次一致,体重约20kg的健康的杜×长×大三元杂交断奶仔猪(公母各半),随机分为4组,每组3个重复,每个重复6头猪。处理Ⅰ为对照组,饲喂玉米-豆粕型基础日粮,处理Ⅱ、Ⅲ和Ⅳ为试验组,分别在基础日粮中添加0.1%,0.2%,0.3%植酸酶和纤维素酶的复合酶制剂,研究复合酶制剂对仔猪生长性能及养分消化率的影响。结果表明:试验组仔猪的平均日增重、饲料转化率以及营养物质的消化率均高于对照组,其中处理Ⅲ的效果最好,但各组的采食量差异不大。