8种不同来源菜籽饼粕的生长猪氨基酸回肠消化率评定

本研究旨在评定8种不同来源菜籽饼粕对生长猪的氨基酸回肠消化率。选取初始体重相近(33.21±1.56)kg、在回肠末端安装简单T-型瘘管并恢复良好的DLY生长阉公猪12头,随机分配到2个6×6拉丁方试验中,每个拉丁方均含1个无氮饲粮、1个基础饲粮和4个试验饲粮处理。试验共6期,每期7 d,前5 d为适应期,后2 d收集回肠食糜。结果表明:除蛋氨酸外,不同来源菜籽饼粕中其他氨基酸回肠表观(标准)消化率差异显著(P<0.05)。赖氨酸、蛋氨酸、苏氨酸和色氨酸4种限制性氨基酸回肠表观消化率变化范围依次为41.73%~60.19%、69.35%~76.90%、50.72%~61.37%和52.49%~68.14%;回肠标准消化率变化范围依次为48.65%~66.14%、73.85%~81.15%、57.42%~67.67%和57.10%~73.04%。总之,菜籽粕中绝大部分氨基酸回肠表观(标准)消化率显著高于菜籽饼。     

2种指示剂测定玉米干酒糟及其可溶物生长猪标准回肠氨基酸消化率的比较研究

本试验旨在研究三氧化二铬和氧化钛2种指示剂对测定玉米干酒糟及其可溶物(D D G S)生长猪标准回肠氨基酸消化率的影响。试验选用6头安装简单T型瘘管的三元杂交(杜洛克×大白×长白)去势公猪,初始体重为(35.1±2.1)kg,应用6×6拉丁方试验设计,分为6期,6种日粮,分别以三氧化二铬和氧化钛配制4种含D D G S日粮,2种无氮日粮。结果表明:玉米D D G S的赖氨酸和色氨酸标准回肠消化率最低;除组氨酸和苯丙氨酸外,2种指示剂对测定其他必需氨基酸和非必需氨基酸标准回肠消化率均无显著影响(P>0.05)。结果提示,三氧化二铬和氧化钛均可用于测定玉米D D G S氨基酸消化率。     

精油对生长猪蛋白质和氨基酸等回肠末端表观消化率的影响

试验旨在通过采用T型瘘管法,研究精油对生长猪蛋白质和氨基酸等回肠末端表观消化率的影响。试验选用6头(杜×长×大)去势公猪([28.6±1.3)kg],采用3×3双拉丁方试验设计,分别饲喂正对照日粮:玉米-豆粕型基础日粮+抗生素;负对照日粮:无抗基础日粮;精油组日粮:负对照+0.01%精油。每个试验期为7 d,前5 d为适应期,后2 d为食糜收集期。结果表明,在日粮中添加精油可提高(P<0.05)蛋白质、能量、精氨酸、赖氨酸、亮氨酸、色氨酸、蛋氨酸、丙氨酸、总必需氨基酸、总氨基酸的回肠末端表观消化率,并有提高干物质、苏氨酸、天冬氨酸、丝氨酸和酪氨酸表观消化率的趋势(P<0.10)。在日粮中添加0.01%的精油可提高生长猪蛋白质、能量、总必需氨基酸和总氨基酸的回肠末端表观消化率,并有提高干物质表观消化率的趋势。     

几种饲料原料的猪氨基酸回肠末端表观消化率和真消化率的测定

试验选用起始体重为(35±1.04)kg的5头健康去势公猪(大白×长白),采用5×5拉丁方设计测定了玉米、豆粕、花生粕和乳清粉的氨基酸回肠末端表观消化率,采用水解酪蛋白法测定了氨基酸的内源损失,并计算得出4种原料的氨基酸回肠末端真消化率。本试验测得的4种原料的赖氨酸、蛋氨酸、苏氨酸、色氨酸的表观消化率与真消化率与中国饲料数据库2004年第15版推荐范围比较吻合。     

用直接技术测定玉米蛋白粉猪回肠表观氨基酸消化率

本试验采用直接技术 ,测定玉米蛋白粉的 18种猪回肠表观氨基酸消化率。选择的玉米蛋白粉是具有我国代表性的玉米加工副产品 ,粗蛋白质含量分别为 6 3% ,5 2 %和 4 7%。 6头T型瘘管猪平均体重 (4 7± 2 .81)kg,6× 6拉丁方试验设计。试验结果表明 ,玉米蛋白粉的蛋氨酸、酪氨酸、亮氨酸和苯丙氨酸回肠表观氨基酸消化率相对较高 ;不同蛋白质含量的玉米蛋白粉的色氨酸、酪氨酸和亮氨酸回肠表观消化率有显著性差异 (P <0 .0 5 )。赖氨酸、色氨酸和组氨酸分别是玉米蛋白粉的第一、第二和第三限制性氨基酸。加工工艺影响玉米蛋白粉猪回肠表观氨基酸消化率     

不同蛋白质含量和热处理对4种不同来源菜籽粕的猪消化能、代谢能含量和氨基酸消化率的影响

为研究4种不同来源的菜籽粕(高蛋白质,高温处理,低温处理和传统菜籽粕)添加到生长猪豆粕型日粮中对消化能、代谢能和粗蛋白质、氨基酸表观和标准回肠消化率的影响,试验选用148头阉割生长猪(初始体重:39.7±1.58 kg),采用完全随机区组设计分配到代谢笼中,24头猪为一组,每组8个重复。试验日粮包含玉米基础日粮和5种试验日粮,混合玉米和4种菜籽粕的一种(添加水平为39%)或豆粕(添加水平为28.5%)。在5 d的预饲期后,连续收集粪尿5 d。每种菜籽粕和豆粕的消化能、代谢能的计算采用不同的程序。4种不同来源菜籽粕的消化能和代谢能显著低于玉米和豆粕(P0.05)(消化能:2854、2680、2892、2883 kcal/kg vs 3324和3784 kcal/kg;代谢能:2540、2251、2681、2637 vs 3213和3253 kcal/kg)。4种来源菜籽粕间的消化能和代谢能无显著差异。在试验2,12头在回肠末端按有T型瘘管阉割生长猪(初始体重:34±1.41 kg)采用6×6拉丁方设计,每个拉丁方6种试验日粮,6个阶段。5种试验日粮包含35%豆粕或45%4种菜籽粕的1种,氨基酸是平衡的和使用无氮基础日粮。每个阶段持续7d,在每个阶段第6 d和第7 d收集回肠内容物。豆粕粗蛋白质和氨基酸的表观和标准回肠消化率显著高于4种来源的菜籽粕(P0.05)。与传统菜籽粕相比,高温工艺处理菜籽粕异亮氨酸、赖氨酸、天门冬氨酸、胱氨酸和脯氨酸的表观回肠消化率,赖氨酸和胱氨酸的标准回肠消化率均显著提高(P0.05)。没有观察到高温处理和低温处理菜籽粕氨基酸消化率的不同。总之,无论菜籽粕加工工艺和粗蛋白质水平,与玉米和豆粕相比,菜籽粕具有较低的消化能和代谢能,菜籽粕氨基酸标准回肠消化率也低于豆粕。在本试验中,加工温度不影响菜籽粕的代谢能、消化能或氨基酸的标准回肠消化率。高温处理菜籽粕的赖氨酸和胱氨酸的标准回肠消化率要高于传统工艺生产的菜籽粕。     

国外畜牧科技

生长猪所饲的低植酸玉米、正常玉米及大豆饼中钙、磷和氨基酸的消化率R.A.Bohlke等著赵海燕摘王楚端校摘要:在9头生长阉猪的回肠末端安装T型套管用于测定低植酸玉米、正常玉米、大豆饼以及大豆饼与低植酸玉米或正常玉米的混合日粮中Ca和P的表观回肠消化率(AID)以及表观总消化道消化率(ATTD)。同时也测定CP和AA的表观回肠消化率系数(AID)和标准回肠消化率系数(SID)。试验猪初始体重为29.3±1 kg,设计9种日粮和9个阶段的9×9拉丁方。含有低植酸玉米、正常玉米和大豆饼的3种日粮分别作为CP、AA、Ca和P的唯一来源。其余3种日粮和这3…     

玉米、玉米副产品和面包副产品饲喂生长猪的氨基酸消化率

文章旨在测定面包副产品、玉米蛋白粉、玉米糠麸饲料、玉米胚芽粕和玉米麸的粗蛋白（CP）和氨基酸（AA）的表观回肠消化率（AID）和标准回肠消化率（SID）,并将这些值与玉米和玉米干酒精糟及可溶物（DDGS）的粗蛋白和氨基酸表观回肠消化率和标准回肠消化率进行比较。8头生长阉公猪[初始体重(82.5±5.5) kg],随机分配,按照8×8的拉丁方设计,8种日粮和8个阶段。日粮分别以玉米、DDGS、面包副产品、玉米蛋白粉、玉米糠麸饲料、玉米胚芽粕和玉米麸作为唯一的蛋白和氨基酸来源。使用无氮日粮测定氨基酸和蛋白质的基础内源性损失。试验日粮分成8个阶段饲喂给试验猪只,每个阶段7 d,每个阶段的第6和第7 d收集回肠食糜。结果显示,玉米蛋白粉的赖氨酸SID（78.7%）高于（P<0.01）DDGS、面包副产品、玉米胚芽粕和玉米麸的赖氨酸SID (分别为46.0%、48.4%、68.4%和58.8%)。面包副产品和DDGS的必需氨基酸（除精氨酸、亮氨酸和蛋氨酸外）的SID没有差异。玉米糠麸饲料的精氨酸、组氨酸、亮氨酸和蛋氨酸的SID比玉米的低（P<0.01）,除此之外,其他所有必需氨基酸的SID,玉米糠麸饲料和玉米没有显著差异。然而,对于大多数的必需氨基酸而言,玉米糠麸饲料和DDGS的SID没有差异。除精氨酸、组氨酸、亮氨酸和蛋氨酸外,玉米胚芽粕的必需氨基酸SID和玉米的必需氨基酸SID没有差异。同样地,除精氨酸、亮氨酸和赖氨酸外,玉米胚芽粕的必需氨基酸SID和DDGS的必需氨基酸SID没有差异。玉米麸的异亮氨酸、蛋氨酸、苯丙氨酸和缬氨酸SID低于玉米的（P<0.01）,但是除此之外的其他必需氨基酸的SID玉米麸和玉米没有差异。除精氨酸和赖氨酸外,玉米麸的所有其他必需氨基酸的SID和DDGS的必需氨基酸的SID没有差异,玉米麸的精氨酸和赖氨酸的SID高于（P<0.01）DDGS的精氨酸和赖氨酸的SID。总之,面包副产品的大多数氨基酸的SID低于玉米的,但是,玉米蛋白粉的大多数氨基酸的SID高于玉米、面包副产品和玉米副产品的氨基酸SID。     

喷雾干燥鸡血浆蛋白粉在仔猪上的营养价值评定

本试验旨在对喷雾干燥鸡血浆蛋白粉在仔猪上的营养价值进行评定。试验采用单因子设计,将24头健康的"杜×长×大"三元杂交去势公猪(初始体重(24.96±1.05)kg)随机分配到3个处理,每个处理8个重复。分别饲喂无氮饲粮、玉米-豆粕型基础饲粮、鸡血浆蛋白粉饲粮(等氮替代基础饲粮中40%的氮)。所有仔猪预饲6d后,进行4d的消化代谢试验,收集全部粪尿,用于测定养分消化率和利用率。试验结束后所有仔猪麻醉屠宰,采集回肠末端食糜,用于测定氨基酸表观回肠消化率和标准回肠消化率。结果表明:喷雾干燥鸡血浆蛋白粉的粗蛋白质高达69.36%,赖氨酸含量为4.53%,蛋氨酸含量为1.65%,赖氨酸∶蛋氨酸∶色氨酸∶苏氨酸=100∶36∶30∶91,与猪的理想蛋白质氨基酸模式较接近;鸡血浆蛋白粉的表观消化能为16.02 MJ·kg-1,表观代谢能为15.39MJ·kg-1;粗蛋白质的表观消化率和真消化率分别为87.58%和91.11%;除了甘氨酸外,所有氨基酸的标准回肠消化率都高于80%。综上表明,喷雾干燥鸡血浆蛋白粉是一种优质的动物性蛋白质原料。     

木薯渣对生长肥育猪饲用价值的研究

试验旨在研究木薯渣营养成分的表观消化率及其以不同比例替代日粮中玉米对生长肥育猪生长性能的影响。根据研究需要设计了2个试验。试验1:选用8头健康、体重(22.46±1.08)kg的杜×长×大三元杂交阉公猪作为试验动物,进行木薯渣养分消化试验。预试期10 ｄ,正试期5 ｄ。试验2:选择160头健康、体重(21.09±0.72)kg的杜×长×大三元杂交猪,随机分为5组,每组4个重复,每个重复8头猪。对照组饲喂基础日粮,试验1~4组分别饲喂以5%、10%、15%和20%木薯渣替代基础日粮中玉米的试验日粮。预试期5 d,正试期30 d。结果表明,木薯渣中粗蛋白质和脂肪含量均较低,分别为2.73%和0.68%,而粗纤维含量却高达15.34%,总能含量为13.55 MJ/kg;氨基酸含量也较低,赖氨酸(Lys)含量为0.11%,苏氨酸(Thr)含量为0.08%;钙、磷表观消化率较低,分别为40.24%和34.76%,总能的表观消化率为65.62%;16种氨基酸中精氨酸(Arg)、谷氨酸(Glu)、酪氨酸(Tyr)、蛋氨酸(Met)、亮氨酸(Leu)和缬氨酸(Val)的表观消化率均高于80%;随着日粮中木薯渣添加比例增加,猪的平均日增重降低,其中添加15%和20%木薯渣组显著低于对照组(P< 0.05),而添加5%和10%木薯渣组平均日增重与对照组相比均无显著差异(P >0.05);通过对饲料成本分析,添加木薯渣5%和10%组的每千克增重饲料成本比对照组分别降低了0.01和0.05元。综上所述,在本试验条件下,20~50 kg生长育肥猪日粮中木薯渣的添加量以5%~10%为宜。     

Ileal digestibility of nutrients and amino acids in unfermented,fermented soybean meal and canola meal for weaning pigs

Apparent ileal digestibility (AID) of energy, dry matter, nitrogen and amino acids and standardized ileal digestibility (SID) of nitrogen and amino acids were evaluated in six weanling pigs ((Landrace × Yorkshire) × Duroc)) fed unfermented soybean meal (SM), yeast fermented soybean meal (SMY), bacillus fermented soybean meal (SMB), yeast and bacillus fermented soybean meal (SMYB), canola meal (CM) and nitrogen‐free diet. Pigs having body weights 17.00 ± 0.3 kg were surgically equipped with T‐cannulas of approximately 15 cm prior to the ileo‐cecal junction and randomly allotted to one of five dietary treatments and a nitrogen‐free diet in 6 × 6 Latin squares. AID and SID of nitrogen (N) was greater (P < 0.05) in SMYB and SMB compared with SM and CM. AID and SID of amino acids such as, Lys (lysine) and Phe (phenylalanine) as well as total essential amino acids were greater (P < 0.05) in SMB and tended to be low in CM compared with SM. AID and SID of aspartic acid (Asp) and glycine (Gly) tended to be higher in SMB compared with SM and other diets except CM. In conclusion, fermentation of soybean meal by Bacillus showed better digestibility of amino acid and nutrients.     

Determination of the ileal amino acid and energy digestibilities of corn distillers dried grains with solubles using grower-finisher pigs

An experiment evaluated the ileal apparent and standardized AA and apparent energy digestibilities in grower-finisher pigs of 5 sources of distillers dried grains with solubles (DDGS) from corn. The 5 DDGS sources were analyzed for AA, GE, NDF, ADF, and color score. Diets were formulated to contain 15% CP from the test DDGS sources (approximately 60% of the diet). A low-protein (5% casein) diet was used to estimate basal endogenous AA losses. The experiment was conducted in 2 replicates of a 6 x 6 Latin Square design, with 6 treatments and six 1-wk periods. The experiment used 12 crossbred barrows [(Yorkshire x Landrace) x Duroc], averaging 28 kg of BW and 60 d of age, and surgically fitted with a T-cannula in the distal ileum. After a 10-d recovery period, treatment diets were fed in meal form, initially at 0.09 kg . BW(0.75). Feed intake was equalized between pigs within each period and increased for each subsequent period. Periods included 5 d of diet acclimation followed by two 12-h ileal digesta collections, one on d 6 and one on d 7. Apparent and standardized digestibility of AA was calculated using chromic oxide (0.4%) as an indigestible marker. The results demonstrated that apparent and standardized lysine digestibilities ranged from 24.6 to 52.3% and 38.2 to 61.5%, respectively. Average apparent essential AA digestibility was lower (P < 0.05) in sources 1 and 5, the 2 sources that were darkest in color. Apparent and standardized digestibility of the averaged nonessential AA were lower (P < 0.05) in source 5 than in all other sources. Source 5, the darkest colored DDGS, had a 10% lower (P < 0.05) average apparent and standardized essential AA digestibility and was more than 15% lower (P < 0.05) in lysine digestibility than the 3 lightest colored sources. Apparent ileal energy digestibility did not differ among the 5 sources. Lysine content and digestibility seemed to be reduced to a greater extent by the darker colored DDGS than the other essential AA, suggesting that the Maillard reaction reduced total lysine content and lowered its digestibility. These results, therefore, imply that darker colored DDGS sources may have lower (P < 0.05) analyzed lysine contents, as well as lower (P < 0.05) lysine and essential AA digestibilities, than lighter colored DDGS sources.     

Nutritional value of quality protein maize for starter and finisher swine.

Growth trials with starter (n = 120, 6.8 kg initially, 28 d of age, Exp. 1) and finisher (n = 70, 59 kg initially, Exp. 2) pigs were conducted to compare quality protein maize (QPM, .40% lysine) and normal corn (.31% lysine) in simple corn-based diets containing the same levels of soybean meal. In Exp. 1, pig performance was similar (P greater than .10) on all diets, regardless of the level of soybean meal, suggesting that QPM and normal corn have similar feeding value in lysine-adequate (.99 to 1.11%) diets. In Exp. 2, less soybean meal was needed in QPM than in normal corn diets to maximize performance; increasing soybean meal from 10.8 to 13.8% improved rate (P less than .05) and efficiency (P less than .01) of gain of pigs fed normal corn diets but had no effect on performance of pigs fed QPM diets. A QPM-based diet containing 6% soybean meal and supplemental lysine and tryptophan failed to maximize feed efficiency, but growth rate was equal to that obtained on the normal corn diet with 13.8% soybean meal. The apparent fecal digestibility of GE and ileal digestibility of N were similar for QPM and normal corn, but apparent ileal digestibility of most essential amino acids was slightly higher for QPM (Exp. 3). Experiment 4 compared apparent digestibilities of QPM, conventional opaque-2 corn and two high-protein corns. Digestibilities differed (P less than .05) among the corns, but the absolute differences were small and were likely due to differences in amino acid content of the corns.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dietary lysine and threonine requirements of the pregnant sow estimated by nitrogen balance

Two experiments were conducted to determine the lysine and threonine requirements of gestating sows. In the first experiment, four levels of lysine (0.34,0.42,0.48, and 0.56% crude lysine, and 0.24,0.31, 0.38, and 0.45% standardized ileal digestible lysine) were compared in eight multiparous Large White sows. Each sow received successively the four diets according to a Latin-square experimental design. Nitrogen balance was measured over 11 d after a 10-d period of adaptation to the experimental diet. In the second experiment, four threonine/lysine ratios (0.63, 0.73, 0.80, and 0.89 on a crude basis and 0.61, 0.71, 0.77, and 0.87 on a standardized ileal digestible amino acid basis) were compared in 16 multiparous sows, according to a Latin-square experimental design. The standardized ileal digestibility of amino acids in the experimental diets was determined with ileo-rectal anastomized growing pigs. In the first experiment, nitrogen retention was affected by lysine supply (linear, P < 0.001; quadratic, P < 0.04). Nitrogen retention was lowest for treatment 1 (8.0 g/ d) and highest for treatments 3 and 4 that did not differ. Nitrogen retention plateaued at 14.7 g/d in sows consuming 10.5 g/d of digestible lysine. The maintenance requirement for digestible lysine was calculated to be 27 mg/kg BW(0.75) with an efficiency of utilization of digestible lysine above maintenance at 59%. In the second experiment, nitrogen retention was affected (P < 0.03) by the threonine:lysine ratio. It was lower for the lowest threonine:lysine ratio (0.63) than for the other three treatments that did not differ among each other. These results indicate that the optimal standardized digestible threonine:lysine ratio appears to be about 0.71 for multiparous gestating sows.     

Apparent digestibility of nitrogen and amino acids in protein feedstuffs by growing pigs

Eight digestion trials were conducted with pigs fitted with ileal T-cannulas to determine the apparent digestibilities of N and amino acids in common protein feedstuffs. Trial-to-trial variation was minimal as determined by the variation in digestibilities for soybean meal, which was evaluated in each trial. Apparent digestibilities varied widely; ileal N digestibility ranged from 88 to 63%, and ileal lysine digestibility ranged from 93 to 40%. In general, ring-dried blood meal, corn gluten meal, Menhaden fish meal, poultry-by-product meal and extruded whole soybeans were the most digestible, followed by canola meal, sunflower meal, peanut meal and meat and bone meal. Cottonseed meal and feather meal were the least digestible. Mean values for each feedstuff agree well with published data. Variation in digestibilities among samples of the same feedstuff was greater for the meat and bone meals. Regression of ileal essential amino acid digestibilities on ileal and fecal N digestibility indicated that amino acid digestibilities can be predicted more precisely from ileal N digestibility than from fecal N digestibility. However, neither ileal nor fecal N digestibility could be used with a high degree of certainty to predict ileal amino acid digestibilities.     

Nutritional value of a genetically improved high-lysine, high-oil corn for young pigs

Two experiments were conducted to compare the nutritional adequacy of a genetically improved high-lysine, high-oil corn (HLHOC; .408% lysine, 6.21% fat, as-fed basis) and a high-oil corn (HOC; .289% lysine, 5.97% fat, as-fed basis) for young growing pigs. Experiment 1 used four non-littermate barrows (initially 20.0 kg BW) fitted with ileal T-cannulas in a crossover-designed digestion study. The .75% total lysine diets contained 8.5% casein and an equal amount of lysine (.25%) from the test corn. Apparent ileal digestibilities of amino acids, GE, DM, and CP were similar (P > .10) between diets. Apparent ileal lysine digestibilities were 65 and 71% for the HOC and HLHOC, respectively, assuming the lysine in casein to be 100% digestible. Experiment 2 used 100 barrows reared in a segregated early-weaning environment (initially 8.3 kg BW and 27 d of age) to evaluate five corn-soybean meal-based diets in a 2 x 2 factorial arrangement with main effects being corn type and dietary lysine (.80 or 1.15% digestible lysine). The fifth diet consisted of the .80% digestible lysine HOC diet supplemented with .23% additional L-lysine x HCl (.975% digestible lysine) to verify that lysine was the limiting amino acid in the low-lysine diets. Increasing digestible lysine from .80 to 1.15% increased (P < .001) ADG and gain/feed (G/F) regardless of corn variety. Combined ADG and G/F were .347 kg and .641 and .443 kg and .790 for the .80 and 1.15% digestible lysine diets, respectively. Within lysine level, corn type did not affect ADG, ADFI, or G/F (P > .10). The results of these studies indicate that the lysine in HLHOC is as available as the lysine in HOC and that HLHOC can be used successfully in swine diets.     

Ileal amino-acid digestibility of wheat, autoclaved wheat and spaghetti by-products for broiler chicks

An experiment was conducted to determine true and apparent ileal amino‐acid digestibility of a native cultivar of wheat (Mahdavi), autoclaved wheat (120°C for 30 min) and spaghetti by‐products available in Iran. One hundred 21‐day‐old broiler chickens were fed a standard corn–soybean meal starter diet from day 0 to 28 post hatch. At 28 days 80 chicks were distributed according to possessing very nearly the same average bodyweight to 20 wire cages. The experimental units were allocated at random to five dietary treatments with four replicates per treatment. The basal diet contained corn and soybean meal as the major ingredients. Three test diets were formulated containing wheat, autoclaved wheat and spaghetti by‐products as the sole source of dietary protein and each test diet was combined with a basal diet 50:50 on a weight basis to form three assay diets. The apparent and true digestibility of amino acid in the test ingredients were estimated from those in the assay diets basal/test diet mixtures, using the difference method. The apparent and true amino‐acid digestibility of the test ingredients were significantly different (P < 0.01). Autoclaving of wheat increase its amino‐acid digestibility (P < 0.01). Among the test ingredients, the average ileal amino‐acid digestibility of spaghetti by‐products was higher than wheat and autoclaved wheat but it was lower than values for the basal diet (P < 0.01).     

Evaluation of the homoarginine technique for measuring true ileal amino acid digestibilities in pigs fed a barley-canola meal-based diet

The homoarginine technique has been suggested as a means to determine true ileal amino acid digestibilities in nonruminant animals fed protein-containing diets. Conditions for guanidinating lysine to homoarginine in barley and canola meal and the effect of this process on nutrient composition and ileal digestibilities in the resulting material were investigated. Conditions tested were methylisourea concentration (0.4, 0.5, or 0.6 M) and reaction time (4 or 6 d) at pH 10.5. Using 0.4 methylisourea M solution for 4 or 6 d gave guanidination rates of 72.5 and 78.5% for barley and 72.3 and 75.2% for canola meal, respectively. Using 0.5 M gave 88.0 and 84.6% guanidination rates in barley and canola meal, respectively, after a 6-d reaction time. Under these conditions, guanidination did not change the nutrient composition of barley (P > 0.10), whereas it increased CP (38.4 vs 49.0%), crude fiber (10.2 vs 16.0%), acid detergent fiber (30.0 vs 43.4%) and neutral detergent fiber (29.8 vs 49.4%) levels in canola meal (P < 0.05). Four 33.6-kg barrows fitted with a simple T-cannula at the terminal ileum were fed a 16% CP unguanidinated barley and canola meal-based diet for four consecutive 14-d periods. Ileal digesta were collected continuously for 24 h on d 12 and 14 to determine apparent nutrient digestibilities. On the morning of d 14, pigs were fed a diet in which half of the barley and canola meal was replaced with guanidinated material for determining true ileal amino acid digestibilities. Digesta samples were pooled by pig and by 24-h period to give 16 observations per diet. Apparent ileal digestibilities of DM, CP, and AA in the unguanidinated and guanidinated barley-canola meal diet were similar (P > 0.10) despite the changes observed in canola meal. Apparent ileal lysine digestibility was 73.9 and 74.5% in the unguanidinated and guanidinated diet, respectively. The true ileal lysine digestibility was 88.1%. The present results show that guanidination does not interfere with digestion and further support the use of the homoarginine method for determining true ileal amino acid digestibilities in pigs fed practical diets. A methylisourea solution of 0.5 M and a 6-d reaction time are recommended for converting lysine to homoarginine in barley and canola meal.     

Neutral detergent fiber increases endogenous ileal losses but has no effect on ileal digestibility of amino acids in growing pigs

Two experiments were conducted to determine the effect of neutral detergent fiber (NDF) on endogenous amino acids and protein ileal losses; and also apparent ileal digestibility (AID), and standardized ileal digestibility (SID) of amino acids and crude protein. Sixteen barrows were fed four protein‐free diets containing graded NDF levels in Experiment 1. NDF was a mixture of sugarcane bagasse and corn leaves (SBCL). Twenty‐four barrows were fed diets with soybean protein concentrate (SPC) or casein as protein sources and SBCL or corncobs (CC) as NDF sources in Experiment 2. In Experiment 1, a linear increase (P < 0.05) in endogenous amino acid and protein ileal losses was observed with increased NDF levels, except for arginine, histidine, methionine and proline. In Experiment 2, protein (P < 0.001) and NDF (P < 0.01) sources significantly affected AID of dry matter, which was higher in casein diets (71.7%) and CC diets (70.7%). Protein and NDF sources significantly affected (P < 0.05) SID of crude protein, which was higher in casein diets (92.8%) and CC diets (92.7%). NDF source had no effect (P > 0.05) on SID of amino acids. Overall, this study showed that NDF increased endogenous amino acid and protein ileal losses, but did not affect ileal digestibility of amino acids.