饲用羽毛肽粉营养成分分析

采用国标及通用的方法,对饲用羽毛肽粉中各营养成分进行分析,并与其它饲料蛋白源进行比较。结果表明,饲用羽毛肽粉粗蛋白、粗脂肪、糖分和粗灰分、盐分含量分别为85.05%、7.9%、1%7、.76%、0.9%。饲用羽毛肽粉含有18种氨基酸,总氨基酸、必需氨基酸和呈味氨基酸分别占总量的70.47%、27.78%、38.70%,总氨基酸占蛋白质的82.86%,必需氨基酸和呈味氨基酸分别占氨基酸总量的39.42%和54.92%。饲用羽毛肽粉作为鱼粉替代品的限制性氨基酸为赖氨酸(Lys)、组氨酸(His)、色氨酸(Trp)、蛋氨酸+胱氨酸(Met+Cys)。饲用羽毛肽粉含14种脂肪酸,不饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸、ω-3不饱和脂肪酸分别占脂肪酸总量的25%、15%、10%、2%,EPA占脂肪酸含量的2%,未发现含有DHA。饲用羽毛肽粉含有丰富的营养成分,但其作为水产动物饲料蛋白源在氨基酸平衡及不饱和脂肪酸含量较鱼粉差,可通过调整营养配方,改善其应用价值。     

The value of crude protein content and in vitro pepsin digestibility of abattoir by-product meals in the prediction of their available protein content

Amino acid composition of meat-and-bone meals, poultry by-product meals, blood meals, bone meals and feather meals showed characteristic differences. Meat-and-bone meals and blood meals had surplus in lysine, whereas poultry by-product meals and feather meals were relatively rich in cystine. Blood meals had high levels of branched-chain amino acids as compared to isoleucine. In vitro pepsin digestibility of meat-and-bone meals (79.9 +/- 17.7%; n = 24) and blood meals (95.8 +/- 4.2%; n = 11) was found to be higher than that of poultry by-product meals (65.3 +/- 7.7%; n = 14) or feather meals (44.7 +/- 9.2%; n = 16). Pepsin digestibility of poultry by-product meals showed a significant negative correlation with crude protein content (r = -0.73; P less than 0.05; n = 14). However, in vitro pepsin digestibility of poultry by-product meals as well as meat-and-bone meals, blood meals and feather meals, showed insignificant correlations with NPU indices as well as with available crude protein contents of the meals. The NPU values of meat-and-bone meals for rats (29.9 +/- 11.7; n = 100) were lower than those of poultry by-product meals (52.1 +/- 7.1; n = 14). The NPU values of blood meals (6.4 +/- 5.6; n = 11) and feather meals (23.5 +/- 10.0; n = 16), determined as sole sources of protein, were low and they did not elicit weight gain in rats. The available crude protein content of poultry by-product meals (34.3 g/100 g +/- 3.6; n = 14) was higher than that of meat-and-bone meals (17.0 g/100 g +/- 7.3; n = 100).(ABSTRACT TRUNCATED AT 250 WORDS)     

Protein value of feather meal for ruminants as affected by blood additions

In situ digestion and growth studies were conducted to determine the effects of adding blood to feather meal. In the in situ and digestion studies, soybean meal (SBM), blood meal (BM), feather meal (Fth) and two combinations of 55% raw blood and 45% feathers (RB + F) were used. Feathers and blood were combined either before or after steam hydrolysis of feathers. Ruminal escape protein of Fth was greater than that of SBM but less than that of BM (P less than .10) determined in situ after 12 h of incubation. Ruminal in situ protein digestion was lower (P less than .10) than for the other treatments (P less than .10) when blood was hydrolyzed with feathers. Total tract digestibility was similar (P greater than .10) for SBM, BM and the mixture of RB + F when the blood was not hydrolyzed. In the growth study, calves were supplemented with urea, SBM, BM, Fth or a combination of BM and Fth (BM + Fth; each supplied an equal portion of supplemental protein). The slope ratio technique was used to evaluate the protein sources. The most efficiently used protein sources were BM and BM + Fth compared to SBM and Fth (P less than .05). There was a numerical but not significant (P greater than .1) complementary effect of adding BM to Fth. Soybean meal and Fth had similar protein efficiencies (P greater than .20). Estimated amino acid flow to the small intestine based on in situ amino acid degradation suggested that the complementary effect observed for BM + Fth was due to BM supplying lysine and Fth providing sulfur amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Evaluation of feather meal as a source of sulfur amino acids for growing steers

In situ and digestion studies were conducted to evaluate feather meal (FTH), blood meal (BM), and meat and bone meal (MBM) for escape protein content, amino acid composition of the escape protein, true protein digestibility, and digestibility of the individual amino acids. Following 12 h of ruminal incubation, escape protein values were 73.5, 92.4, and 60.8% of CP for FTH, BM, and MBM, respectively. Blood meal and MBM were poor sources of sulfur amino acids (SAA), whereas FTH was a good source. Most of the SAA of FTH, however, was Cys, with very little Met. True protein digestibilities were not different for the protein sources (P > .15), ranging from 86.7 to 94.0% of the CP. However, digestibilities of the individual amino acids were quite different. Two growth studies were conducted to evaluate FTH as a source of SAA for growing cattle. The first study used 120 steers (228 +/- 15 kg) supplemented with urea, MBM, MBM plus 1% FTH, or MBM plus 2% FTH. Additionally, incremental amounts of rumen-protected Met were added to treatments containing MBM. Supplementation of MBM increased (P < .05) ADG compared with the urea control. Addition of FTH to MBM resulted in a linear (P < .01) increase in ADG. However, addition of rumen-protected Met to MBM plus FTH treatments further improved gains. Although FTH is an effective source of SAA, Met probably was first-limiting. The second study used 90 steers (243 +/- 18 kg) supplemented with BM plus incremental amounts of SAA from either FTH or rumen-protected Met. Addition of SAA improved ADG compared with BM alone (P < .05). Rumen-protected Met as a source of SAA improved ADG compared with FTH (P < .05). The SAA from FTH promoted a gain response equal to 50% of the response obtained with rumen-protected Met. Formulation of ruminant diets for metabolizable amino acids must account for escape value and digestibility of each individual amino acid. Feather meal is an effective source of SAA; however, Cys supplies over five times the amount supplied by Met.     

蒸煮酶解羽毛粉的营养价值及其在肉鸭上的能量和氨基酸利用率评定

本试验旨在研究采用真代谢能(TME)法评定3种蒸煮酶解羽毛粉对于肉鸭的能量和氨基酸营养价值,为合理开发和利用羽毛粉蛋白质资源提供基础数据。3种羽毛粉(Ⅰ~Ⅲ)分别为42日龄樱桃谷肉鸭羽毛粉、550日龄罗曼蛋鸡羽毛粉和100日龄三黄肉鸡羽毛粉。试验选取20只7周龄樱桃谷肉鸭,随机分为4个处理,每个处理5个重复,每个重复1只肉鸭,单笼饲养。处理1(T1)为测定羽毛粉Ⅰ,处理2(T2)为测定羽毛粉Ⅱ,处理3(T3)为测定羽毛粉Ⅲ,处理4(T4)为饥饿处理。试验期为7 d。结果表明:1)以干物质(DM)为基础,羽毛粉Ⅰ、Ⅱ、Ⅲ的总能(GE)分别为21.31、21.02和20.18 MJ/kg,表观代谢能(AME)分别为13.71、12.29和12.10 k J/kg,TM E分别为14.83、13.42和13.22 M J/kg。2)以DM为基础,羽毛粉Ⅰ、Ⅱ、Ⅲ的粗蛋白质(CP)含量分别为91.05%、87.31%和91.06%;羽毛粉Ⅰ、Ⅱ、Ⅲ的总氨基酸(TAA)含量都在80%以上,但不同羽毛粉的氨基酸含量差异较大。3)羽毛粉Ⅰ、Ⅱ、Ⅲ的TAA表观可代谢率分别为81.51%、73.07%和76.85%,TAA真可代谢率分别为85.09%、76.89%和80.43%。3种羽毛粉的表观可利用氨基酸和真可利用氨基酸含量也存在显著差异(P0.05)。由此可见,利用TM E法测定毛粉能量与氨基酸的营养价值,发现3种羽毛粉的代谢能(M E)、表观可利用氨基酸和真可利用氨基酸存在明显差异。羽毛粉Ⅰ的GE、ME、CP及TAA代谢率均高于羽毛粉Ⅱ和羽毛粉Ⅲ。     

骨粉和羽毛粉中添加复合酶对临武鸭养分利用率的影响

试验旨在研究添加复合酶对临武鸭骨粉和羽毛粉养分利用率的影响,选用40只体重2.0kg左右的健康成年临武鸭公鸭,随机分为5组,每组8个重复,采用绝食强饲法进行代谢试验,测定添加酶制剂前后临武鸭对骨粉和羽毛粉中DM、CP、粗脂肪、氨基酸、能量等的表观和真可利用率。结果表明：添加复合酶制剂临武鸭对骨粉中干物质、粗蛋白、粗脂肪、粗灰分、钙和总磷的真可利用率分别为提高了9.50%、7.72%、3.46%、8.52%、1.49%和18.94%;骨粉的鸭表观代谢能和真代谢能分别提高了3.64%和5.85%;氨基酸的真可利用率提高了2.65%-24.52%。临武鸭对羽毛粉中DM、CP、EE的真可利用率分别为4.12%、3.21%和1.64%;羽毛粉的鸭AME和TME分别提高了2.38%和2.14%;氨基酸的真可利用率提高了0.75%-12.63%。试验结果显示,在骨粉和羽毛粉中添加复合酶制剂提高了临武鸭的养分及氨基酸利用率和代谢能。     

鸡羽毛的生物转化

从自然界中分离了一种可以降解鸡羽毛粉中角质蛋白的菌种,纯化后菌种中有较强的蛋白质分解能力。生物转化后的羽毛粉氨基酸含量充足,蛋白质的表观消化率达到91.08%,蛋白质的生物学价为83.79%。该菌种不产毒素,动物可以安全饲用。生物转化后的羽毛粉可以替代豆粕、鱼粉等饲料蛋白质,是一种新型、优质的饲料蛋白源。     

Growth performance, carcass characteristics, nutrient digestibility and fecal odorous compounds in growing-finishing pigs fed diets containing hydrolyzed feather meal

This study was designed to determine the effects of hydrolyzed feather meal inclusion on growth performance, carcass characteristics, nutrient digestibility and fecal odorous compounds in modern lean growth genotype pigs. Two hundred forty pigs (BW = 23.2 +/- 1.3 kg) were allotted based on BW and sex to a 2 x 6 factorial arrangement of treatments (four pens per treatment; five pigs per pen) in a randomized complete block design. Factors consisted of 1) sex (barrows or gilts) and 2) dietary treatment (0, 2, 4, 6, 8, or 10% hydrolyzed feather meal). Diets were formulated to contain 1.00, 0.90, 0.75, or 0.60% apparent ileal digestible lysine for phases 1 to 4, respectively, with other amino acids provided at an ideal ratio. Available P and ME were kept constant within each phase. No significant interactions between feather meal inclusion and sex were observed for growth performance (P > 0.15). Body weight gain was reduced (P < 0.05) for pigs fed 10% feather meal compared to pigs fed 0, 4, or 8% feather meal. Feed intake of pigs fed 10% feather meal was reduced (P < 0.05) compared to pigs fed 0 or 4% feather meal. Ultrasound backfat measurements tended (P = 0.12) to increase with increasing levels of feather meal. Daily lean gain was less (P < 0.05) in pigs fed 10% feather meal than in pigs fed either 0, 2, 4, or 8% feather meal. Digestibility of N measured on wk 9 decreased quadratically (P < 0.001) with increasing levels of feather meal. Phosphorus digestibility increased in a linear fashion (P < 0.02), however, the improvement in P digestibility with increasing levels of feather meal was more pronounced in barrows compared to gilts (interaction, P < 0.05). Fecal samples obtained from pigs fed 0, 4, or 8% feather meal were analyzed for odorous compounds. Concentrations of butanoic, pentanoic, and 3-methylbutanoic acid were greater (P < 0.05) and concentrations of 3-methylphenol, 4-methylphenol, indole, and decane were less (P < 0.05) in feces from pigs fed feather meal. These results suggest that feather meal can be included in diets for growing-finishing pigs at a rate of 8%. Excretion of N in feces increased but P excretion decreased with increasing levels of feather meal. Odorous compounds in feces can be affected by the inclusion of hydrolyzed feather meal, but the exact impact of these changes on odor perception remains to be elucidated.     

杂交枸树叶粉营养成分测定与饲用价值研究

研究测定了杂交枸树Broussonetia papyrifera叶粉的粗蛋白、粗纤维、钙、磷等常规营养成分的含量以及17种氨基酸组分。并运用必需氨基酸评分、必需氨基酸指数评价枸树叶粉蛋白质营养价值。用模糊最优局势决策分析法评价其饲用价值。结果表明,杂交枸树叶粉的粗蛋白和17种氨基酸含量分别是23.62%和20.95%,属于蛋白质饲料;必需氨基酸/氨基酸(E/T)为 0.44,必需氨基酸/非必需氨基酸(E/N)为0.80,高于FAO/WHO提出的E/T 应为0.40、E/N应在 0.6以上的参考蛋白模式;氨基酸分是50,低于四倍体刺槐叶粉、松针粉、苜蓿草粉;必需氨基酸指数95.24,与上述饲料比较接近。模糊最优局势决策分析结果是,杂交枸树叶粉饲用价值高于苜蓿草粉和松针粉,低于四倍体刺槐叶粉。     

A comparison of ileal digesta and excreta analysis for the determination of amino acid digestibility in food ingredients for poultry.

1. The apparent ileal and excreta digestibilities of amino acids in 15 samples representing 12 food ingredients were determined using 5-week-old male broiler chickens. The ingredients included 3 samples of cereals (wheat, maize and sorghum), 6 samples of plant protein meals (soyabean meal, cottonseed meal, canola meal and sunflower meal) and 6 samples of animal protein meals (meat meal, meat-and-bone meal, feather meal and fish meal). 2. The test ingredients were incorporated as the sole source of dietary protein in assay diets. Each diet was offered ad libitum to 3 pens (4 birds/pen) from d 35 to d 42 post-hatching. Total collection of excreta was carried out during the last 4 d. All birds were killed on d 42 and the contents of the lower half of the ileum were collected. Apparent ileal and excreta amino acid digestibilities were calculated using acid-insoluble ash as the indigestible marker. 3. The influence of site of measurement was found to vary among food ingredients, among samples within an ingredient and among different amino acids within an ingredient. Ileal amino acid digestibility values were similar in some ingredients, but significantly lower or higher in others than the corresponding excreta values. 4. Average ileal and excreta amino acid digestibilities in sorghum and maize were similar, but significant differences were observed for individual amino acids. In contrast, ileal amino acid digestibility values were higher than the corresponding excreta digestibility values in wheat. 5. The average ileal and excreta digestibilites of amino acids in the 3 soyabean meal samples were similar although small, but significant differences were noted for individual amino acids. Site of measurement had no effect on the digestibility of amino acids in canola meal. Digestibilities of valine, isoleucine, phenylalanine, histidine, glutamic acid, alanine and tyrosine in sunflower meal and those of valine, methionine, isoleucine, leucine, lysine, glutamic acid and alanine in cottonseed meal were lower by excreta analysis. 6. Digestibilities in animal protein meals, with the exception of blood meal and fish meal, were consistently higher by excreta analysis. Ileal-excreta differences in individual amino acid digestibilities were more evident in feather meal, meat meal and meat-and-bone meal. 7. Threonine and valine were the indispensable amino acids that were more frequently influenced by the site of measurement. Of the dispensable amino acids, aspartic acid, serine, glutamic acid and alanine were the most affected. 8. Differences determined between ileal and excreta digestibilities in the present study clearly demonstrate that amino acid metabolism by hindgut microflora in chickens may be substantial and that digestibilities measured in the terminal ileum are more accurate measures of amino acid availability than those measured in the excreta.     

酶解羽毛粉的体外蛋白质消化率及其在生长猪日粮中的应用效果

试验旨在测定酶解羽毛粉的体外蛋白质消化率,同时研究酶解羽毛粉替代日粮中鱼粉对生长猪生产性能和蛋白质消化率的影响。体外试验采用胃蛋白酶-胰酶水解法对水解羽毛粉和酶解羽毛粉进行消化测定其蛋白质消化率。饲养试验选用135头体重相近的杜×长×大生长猪,随机分成3组,分别为对照组(3%秘鲁鱼粉组),处理Ⅰ和Ⅱ(酶解羽毛粉50%和100%替代秘鲁鱼粉)。结果表明:酶解羽毛粉体外蛋白质消化率比水解羽毛粉提高了15.38%(P<0.05)。处理组平均日增重和平均日采食量与对照组均无显著差异(P>0.05);饲料增重比及蛋白质消化率也与对照组差异不显著(P>0.05)。结合生产性能试验与经济效益分析,酶解羽毛粉100%等蛋白替代秘鲁鱼粉组为最佳,在生产实践中具备实用性和可行性。     

The nutritive value of fish meal, meat-and-bone meal and field bean meal as measured by digestibility experiments on the adult colostomised fowl

Digestibility experiments were carried out, using colostomised hens fed semi‐synthetic diets containing fish meal, meat‐and‐bone meal or field bean meal as the sole source of protein. A “nitrogen‐free” diet was fed to one group of three birds.

Metabolic faecal nitrogen (MFN) output of birds consuming about 75 g dry matter/d was 106 mg/d. The amino acid composition of the MFN was determined. Endogenous urinary nitrogen output (one result) was 0.80 mg Wg0–75/d.

The true digestibilities of the crude protein of fish meal, meat‐and‐bone meal and field bean meal were respectively 89, 69 and 83 per cent. Digestibility coefficients of individual amino acids were also determined and it was found that the amino acids were not equally digestible. However, for each protein source most of the coefficients fell within a range of + 5 per cent of the mean.

The metabolisable energy content of the fish meal was 2645 kcal/kg, meat‐and‐bone meal 1988 kcal/kg and field beans 2910 kcal/kg.     

Acute interstitial pneumonia in feedlot cattle: effects of feeding feather meal or vitamin E.

We evaluated the effects of feeding 1.5% cysteine-rich feather meal or 550 IU of vitamin E for 40 d before slaughter on the rates of death and emergency slaughter due to acute interstitial pneumonia (AIP) in commercial feedlots. Blood and lung tissue were collected at slaughter from 83 animals clinically diagnosed with AIP, 40 asymptomatic penmates, and 40 heifers receiving either feather meal (20) or vitamin E (20); the left lung was subsampled for histologic examination. Blood and lung tissue were analyzed for thiol adducts of 3-methyleneindolenine (3ME) and reduced glutathione. Supplementation with feather meal or vitamin E had no effect on the rates of death and emergency slaughter attributable to AIP and did not influence the levels of 3ME or reduced glutathione in blood or lung tissue. Although supplementation with greater amounts of feather meal or vitamin E may have been necessary to significantly affect factors related to feedlot AIP, increased supplementation would be uneconomical for commercial feedlots, given the relatively low incidence of AIP.     

Effect of feather meal as a source of valine for lactating sows

An experiment was conducted to evaluate feather meal as a source of Val in lactating sow diets. Sows (five farrowing groups; mean parity = 2.34) were allotted to one of two dietary treatments on the basis of ancestry, parity, and weight and date of d 110 of gestation. The treatment diets included 1) corn-soybean meal lactation diet (n = 40) or 2) corn-soybean meal lactation diet with 2.5% feather meal (n = 39). The diets were formulated on an equal Lys basis. All litters were adjusted to 10 pigs within 24 h after farrowing, and all sows weaned at least nine pigs. Sows were bled at 110 d of gestation and at weaning, and serum urea N was determined. Backfat thickness was determined ultrasonically at 110 d of gestation and at weaning. Serum urea N and backfat thickness at d 110 of gestation were used as covariates for serum urea N and backfat thickness at weaning, respectively. The litter response criteria (weaning weight, litter weight gain, and percentage survival) were not affected (P > .10) by feather meal. The sow response criteria (weaning weight, weight loss per day, weaning backfat thickness, change in backfat thickness, ADFI, and days to estrus) were not affected (P > .10) by feather meal. Sows fed feather meal had increased (P < .01) serum urea N and tended (P = .15) to have decreased sow weaning weight. Following the initial analysis of the data, the data set was split into two groups: 1) sows with litters gaining less than 2.17 kg/d (n = 19 and 20 for control and feather meal diets, respectively) and 2) sows with litters gaining more than 2.17 kg/d (n = 21 and 19 for control and feather meal diets, respectively). These two groups were analyzed separately. In sows with litters gaining less than 2.17 kg/d, the litter and sow criteria were not affected (P > .10) by treatment. In sows with litters gaining more than 2.17 kg/d, sow weaning weight was decreased (P < .04) and sow weight loss (P < .02) and serum urea N (P < .01) were increased in sows fed feather meal. Feather meal (as a source of Val) did not improve litter weight gain, but it increased serum urea N.     

Hydrolyzed feather meal as a protein source for growing calves

Growth, digestion and in situ studies were conducted to determine the protein value of hydrolyzed feather meal (Fth) for growing ruminants. Dacron bags containing blood meal (BM), Fth, corn gluten meal (CGM) and soybean meal (SBM) were suspended in the rumen of two steers for 12 h to estimate escape protein. The escape protein value for Fth, 69.1%, was less than that for BM (82.8%) and CGM (80.4%; P less than .05) but greater than that for SBM (26.6%; P less than .05). Apparent protein digestion by lambs was similar (P greater than .10) for isonitrogenous diets containing urea (U), BM, Fth, CGM and SBM. Amino acid contents of the protein sources before vs after a 12-h ruminal in situ digestion were similar (P greater than .10). In a growth study, a basal diet of 80% ensiled corncobs and 20% alfalfa was fed to 60 individually fed crossbred steers (215 kg BW). Steers were supplemented with U, BM, Fth, 1/2 BM:1/2 Fth, 1/2 BM:1/2 CGM and 1/3 BM:1/3 Fth:1/3 CGM (protein basis). Protein sources were fed at 30, 45 and 60% of the supplemental N with urea supplying the remainder. Protein efficiency was calculated using the slope ratio technique. Protein efficiency was similar (P greater than .10) for BM- and Fth-supplemented calves. Protein efficiencies were similar (P greater than .10) for BM:CGM, BM:Fth and BM:Fth:CGM combinations. These data indicate the Fth is a digestible high escape protein source that is useful in diets for growing ruminants.     

混合菌株发酵豆粕生产复合蛋白粉研究

以虾壳发酵液和豆粕为原料,根据影响发酵效果的几个因素,设计6组实验,通过测定系列指标,比较不同处理组豆粕的发酵效果。结果表明,发酵豆粕(复合蛋白粉)与原料豆粕相比,感官良好,带有酒香的浓郁酸香味,胰蛋白酶抑制因子和植酸含量显著降低(P<0.05),酸溶蛋白、游离氨基酸、小肽含量显著升高(P<0.05),蛋白质含量显著升高(P<0.05),说明经过混菌发酵,豆粕的营养价值得到极大提高。在各实验组中,以实验5组效果最佳,该组的发酵参数是:发酵原液pH值6.5,添加未灭菌豆粕,料液比为1:1.8,酿酒酵母接菌量为豆粕质量的15%,发酵后12 h添加豆粕质量10%的葡萄糖,发酵温度35℃,发酵时间48 h。     

Comparison of estimates of ruminal protein degradation by in vitro and in situ methods

Ruminal degradation of eight soluble proteins and 10 protein meals was determined using three methods: 1) an inhibitor in vitro system (IIV), to which inhibitors are added to prevent metabolism of protein degradation products, 2) in situ incubations in nylon bags and 3) in vitro NH3 production in typical ruminal inoculum. In vitro NH3 production rate from different proteins was not related to in situ or IIV degradation rate. Degradation rates for soluble proteins by IIV ranged from .103 to .813/h, yielding estimated extents of degradation that ranged from 73 to 94% (assuming ruminal passage of .05/h). For seven of the protein meals, degradation rates measured by IIV were threefold greater than in situ rates. However, mean degraded fractions estimated from zero-time intercepts were twofold greater using the in situ method, and calculated extents of degradation averaged 83% of IIV values. Extents of degradation estimated (assuming ruminal passage of .05/h) for fish meal, soybean meal, linseed meal, sunflower meal, rapeseed meal, copra meal and meat and bone meal were, respectively; 55, 79, 84, 59, 75, 54 and 58% (IIV) and 46, 63, 69, 51, 52, 43 and 55% (in situ). These values were generally similar to those reported in the literature. The extent of degradation of feather meal was 28% by in situ determination. Neither the IIV nor in situ method gave significant regressions for blood meal; neither method yields reliable data for very slowly degraded proteins. The IIV procedure has the advantage over the in situ method because it can yield degradation estimates for soluble as well as insoluble proteins.     

Hydrolysis time as a factor affecting the nutritive value of feather meal and feather meal-blood meal combinations for growing calves

The objectives of this research were to determine 1) the effects of hydrolysis time on feather meal (FTH) protein digestion and ruminal escape and 2) whether adding blood meal (BM) to FTH evoked a complementary response in animal performance. A lamb digestion trial was conducted to estimate true protein digestibility of soybean meal (SBM), BM, and FTH hydrolyzed for 10, 12, 15, or 18 min. Ruminal escape was estimated in situ. Two 94-d growth trials were conducted using 60 growing calves (226 kg) per trial to evaluate urea, FTH, BM, and 87.5:12.5, 75:25, and 50:50 combinations (CP percentage basis) of FTH:BM. There were small numerical differences in estimated escape of protein from the rumen and DM and protein digestibilities due to hydrolysis time. True protein digestibility of the 10- and 18-min samples was 5% higher (P less than .05) than for the 12- or 15-min FTH samples. In the growth trial, the slope-ratio technique showed that the most efficiently used protein supplement was 100% BM (protein efficiency = 2.45 +/- .19). No differences (P = .30) in protein efficiency were observed among supplements containing various combinations of FTH:BM. There was a quadratic (P less than .01) response to the level of BM, indicating a complementary effect. The largest complementary effect occurred at the 12.5% level of the BM addition. There were no nutritionally important effects of hydrolysis time between 10 and 18 min. Furthermore, supplements can be formulated more economically using small amounts of BM with FTH without compromising biological efficiency.     

Ileal amino acid digestibility assay for the growing meat chicken--comparison of ileal and excreta amino acid digestibility in the chicken

1. The apparent and true amino acid digestibilities in sorghum, wheat, soyabean meal, meat-and-bone meal, fish meal and blood meal for growing meat chickens were determined using an assay based on the collection of digesta from the terminal ileum and comparison was made with digestibility values determined using an excreta-based assay. 2. Five-week-old meat chickens were given maize-soyabean meal basal diet or mixtures of the basal diet and test diets containing the 6 ingredients as the sole source of dietary protein (50:50 on weight basis). Apparent amino acid digestibility values of assay diets at ileal and excreta levels were calculated using chromic oxide as the indigestible marker. True digestibility values were calculated using endogenous outputs determined by feeding a protein-free diet. Amino acid digestibilities of the ingredients were calculated by difference. 3. The site of measurement had no influence on endogenous amino acid output, the exceptions being aspartic acid and glutamic acid. The output of these two amino acids was higher in the excreta. 4. Significant differences were found between ileal and excreta-based digestibility of certain amino acids in some ingredients, with excreta values being usually higher than the ileal values, indicating a net catabolism of amino acids in the large intestine. The degree of net amino acid disappearance was found to be variable among amino acids and ingredients. In general, threonine had the lowest digestibility at the ileal level and, compared with other amino acids, the highest degredation during passage through the hindgut. 5. The results showed that digestibility determination based on excreta collection will overestimate the uptake for some amino acids in some feeds. The degree of overestimation was often considerable, ranging from 8.9% (apparent digestibility of threonine in soyabean meal) to 56% (apparent digestibility of aspartic acid in wheat). It is concluded that digestibility values measured at the terminal ileum provide a more reliable measure of amino acid availability than those measured in the excreta.