酶解对豆粕营养成分及体外消化率的影响

为了探讨酶解对豆粕营养价值的影响,试验以豆粕为原料进行体外酶解预消化处理,测定样品的营养成分及体外消化率。结果表明,经过酶解之后的豆粕与原料相比,粗蛋白质、酸溶蛋白、还原糖以及氨基酸含量有了明显的提高(P0.05),氢氧化钾蛋白质溶解度、粗蛋白质消化率以及干物质消化率也有显著增加(P0.05)。酶解之后的豆粕营养价值明显提高。     

矿物元素蛋白盐的生物利用率

经SD品系的大白鼠试验证明 ,钙锌蛋白盐的生物利用率显著高于氨基酸配合物和无机盐 .蛋白盐能显著地提高股骨密度 (p <0 .0 5)以及股骨钙和血清钙含量 ,并能显著地提高血清锌含量 (p <0 .0 1 )以及股骨锌和脑锌含量 ,但氨基酸锌和无机锌的利用率差异不显著 ,说明小肽是一种比游离氨基酸更好的蛋白盐配体 .     

不同品种早稻糙米养分利用率的研究

以艾维菌成年公鸡为试验对象 ,采用真代谢能 (TME)法研究湖北省 8种早稻糙米营养物质的利用率及代谢能值并与玉米比较。结果表明 ,8种早稻糙米的物质、粗脂肪和总能的表现利用率和真利用率平均分别为 83.15 %和 85 .93%、94 .6 7%和 95 .0 3%、93.37%和 95 .71% ,高于玉米 (P <0 .0 1) ,粗蛋白的表观利用率和真利用率平均分别为 4 8.37%和 5 2 .92 % ,显著高于玉米 (P <0 .0 5 )。苏氨酸、缬氨酸、异亮氨酸、亮氨酸、苯丙氨酸、赖氨酸和精氨酸的表观利用率和真利用率平均为 79.32 %和 79.4 9%、83.5 4%和 83.6 8%、81.13%和 81.30 %、83.5 1%和 83.6 3%、82 .0 2 %和 82 .19%、82 .4 8%和 82 .6 2 %、90 .88%和 90 .92 % ,高于玉米 (P <0 .0 1) ,胱氨酸和蛋氨酸的表观利用率和真利用率平均分别为 80 .16 %和 80 .6 5 %、72 .76 %和 72 .91% ,显著高于玉米 (P <0 .0 5 )。表观代谢能和真代谢能值均高于玉米 ,分别为 16 .38MJ kg和 16 .6 8MJ kg。其中表观代谢能与玉米间差异极显著 (P <0 .0 1) ;除鄂早 6号 (P >0 .0 5 ) ,真代谢能与玉米间差异显著 (P <0 .0 5 )。糙米的营养价值相当于或高于玉米 ,是一种良好的能量饲料。     

丙酸钙对西门塔尔牛精饲料瘤胃降解率的影响

以混合精料和玉米秸秆为基础日粮,研究丙酸钙对西门塔尔牛精饲料瘤胃降解率的影响.结果表明:添加丙酸钙200 g/d组的精饲料干物质、有机物和粗蛋白质瘤胃有效降解率较对照组均显著提高(P<0.05);丙酸钙的适宜添加水平为200 g/d.     

不同处理复合油菜籽对蛋鸡的营养价值评定

通过动物实验测定不同处理的复合油菜籽代谢能和营养物质的消化利用率,评定其对蛋鸡的营养价值。实验材料为破碎复合油菜籽、熟化复合油菜籽和膨化复合油菜籽。1)真代谢能法(TME)测定油菜籽代谢能与营养物质利用率:将64只30周龄、体重(3. 00±0.03) kg的海兰褐种公鸡,随机分为4组,分别强饲破碎复合油菜籽、熟化复合油菜籽、膨化复合油菜籽或绝食。2)氨基酸回肠消化率的测定:将48只25周龄、体重(2. 50±0. 02) kg的海兰褐蛋鸡,随机分成3组,分别饲喂纯合无氮饲粮、破碎复合油菜籽半纯合饲粮、膨化复合油菜籽半纯合饲粮。实验结果表明:1) TME法测定结果:熟化复合油菜籽和膨化复合油菜籽的TME值分别为14. 41、14. 59 MJ/kg;与破碎复合油菜籽相比,膨化复合油菜籽的粗脂肪和粗蛋白质表观利用率分别提高21. 79%和25. 22%(P 0. 01);除甘氨酸、组氨酸外,膨化复合油菜籽的氨基酸全肠道表观利用率和真利用率高于破碎复合油菜籽(P 0. 01)和熟化复合油菜籽(P 0. 05);熟化复合油菜籽大部分氨基酸全肠道利用率高于破碎复合油菜籽(P 0. 05)。2)氨基酸回肠消化率:与破碎复合油菜籽相比,膨化油菜籽的各氨基酸回肠表观消化率和回肠标准消化率得到了极显著的提高(P 0. 01),除了组氨酸外,膨化复合油菜籽各氨基酸回肠表观消化率、氨基酸回肠标准消化率都大于83%。复合油菜籽经加热处理尤其是135℃膨化后表观代谢能、粗脂肪、粗蛋白质、氨基酸利用率得到大幅度提高。     

总状毛霉与鲁氏酵母耦合发酵 对豆粕营养和风味的增强效应

本文以总状毛霉为主要菌种,探究发酵对豆粕营养和风味的增强作用以及鲁氏酵母耦合发酵和豆粕原料超声前处理对毛霉发酵豆粕品质的作用。结果表明,总状毛霉发酵能显著提高豆粕中性蛋白酶活力、可溶性蛋白含量、感官品质、总氨基酸和游离氨基酸含量,并有效降低胰蛋白酶抑制剂活力;28 ℃发酵60 h,各发酵豆粕蛋白酶活力和可溶性蛋白含量均达到最大值,与未发酵豆粕相比,总状毛霉发酵豆粕蛋白酶活达到1032.4 U/g,可溶性蛋白、总氨基酸和游离氨基酸含量分别增加3.16倍、13.64%和5.65倍,胰蛋白酶抑制剂活力降低了84.57%。豆粕原料超声前处理和鲁氏酵母耦合发酵均有助于强化毛霉发酵豆粕的品质,其中超声前处理后毛霉和鲁氏酵母耦合发酵豆粕胰蛋白酶抑制剂含量从4375 U/g下降到350 U/g,减少了92%,游离氨基酸含量增加了7.69倍,总氨基酸含量提高了22.92%,有效提高了豆粕的营养和感官品质,为豆粕的进一步研究和应用提供了参考。     

五种云南野生食用菌中非挥发性的主要呈味物质比较研究

采用高效液相色谱仪及全自动氨基酸分析仪对黑牛肝菌、黄牛肝菌、鸡枞菌、干巴菌、松茸菌等5种云南野生食用菌品种进行肌苷酸、氨基酸总量及游离氨基酸含量比较分析,结果表明,黑牛肝菌中肌苷酸含量最高,达1326.48μg/g,显著高于干巴菌(890.98μg/g)、松茸菌(513.83μg/g)(p0.05)。5种云南野生食用菌均含17种氨基酸,氨基酸总量在不同品种间差异性显著(p0.05),鸡枞菌的氨基酸总量达158.06 mg/g,并显著高于其它四种菌(p0.05),其次是黑牛肝菌(112.26 mg/g);五种野生菌中必需氨基酸占总氨基酸的比例均在40%以上,氨基酸配比合理,5种云南野生食用菌均属优质蛋白;另外,鸡枞菌的风味氨基酸含量最高,其中鲜味游离氨基酸含量达9.35 mg/g,显著高于其它菌种,其次是黄牛肝菌(5.11 mg/g)。5种云南野生食用菌呈味物质含量丰富,其应用于食品调味料产品具有较好的前景。     

米曲霉PRB-1蛋白酶系和淀粉酶系与高盐稀态酱油理化特性关系的研究

本文采用一株自行分离的米曲霉PRB-1菌株(AP)进行制曲和高盐稀态酱油发酵。结果表明:AP成曲的酸性和中性蛋白酶活力达到398.53 U/g干基和1539.98 U/g干基,较米曲霉3.042(AO)分别提高71.79%和59.93%。AP成曲淀粉酶活力比AO略低。AP成曲含有5个中性蛋白酶组分,2个酸性蛋白酶组分和4个淀粉酶组分。其中,蛋白酶Rf6号和淀粉酶Rf3号活力最大。随着发酵时间的延长,AP和AO酱醪总酸含量呈现上升趋势。p H值由中性持续下降至偏酸性。氨基态氮含量持续增加,还原糖含量均呈现先显著上升后缓慢降低的趋势。发酵55d AP头油的氨基态氮含量为0.86 g/100 m L,原料利用率为81.97%,氨基酸生成率为61.37%,较AO均有较高的优势。AP头油的还原糖含量为4.82 g/100 m L,低于AO。成曲的中性蛋白酶活力和发酵酱油的氨基酸生成率呈正相关(p0.05),对其他指标无显著影响(p0.05)。     

施用有机无机复合肥对白菜主要品质因素的影响

通过盆栽实验,对白菜施用豆粕类控释型有机无机复合肥的效果进行分析。与无机复合肥相比,白菜施用豆粕类控释型有机无机复合肥能极显著地提高干物质含量,能显著地降低硝酸盐含量,但不能提高生物产量。对豆粕类控释型有机无机复合肥不同施氮水平进行分析,1.6g/10kg的施用量在生物产量方面显著高于0.8g/10kg的施用量,但在干物质含量和硝酸盐含量方面,不同氮素水平间差异不显著。综合考虑三因素,以1.6g/10kg的施氮量为佳,即在不降低干物质含量和不增加硝酸盐含量的基础上,可显著提高产量,而2.0g/10kg的施氮量,不仅产量低,而且增加成本,不宜采用。     

日粮代谢能水平对鹅生长性能、养分利用率及肉质的影响

探讨日粮代谢能水平对鹅生长性能、养分利用率及肉质的影响。选取4周龄、体重相近的杂交鹅60只,随机分为3个组,每个组两个重复,每个重复10只(公、母各5只),进行为期42 d的饲养试验。结果表明:随着日粮中代谢能水平的升高,各组试验鹅平均日增重提高了,料肉比得到了改善,各组平均日增重、平均日采食量和料重比差异不显著(P>0.05);日粮中干物质、能量和粗纤维的代谢率降低显著(P<0.05);鹅肉中的干物质、粗蛋白质、氨基酸总量、必需氨基酸总量、肌内脂肪、肌苷酸含量各组间差异不显著(P>0.05),肌内脂肪和肌苷酸有升高的趋势(P>0.05),肌肉香味有改善的趋势。     

Influence of dietary protein degradability and energy concentration on growth of heifers and steers and intraruminal protein metabolism

Two studies with 4-mo old Holstein steers and heifers and one abomasal digesta collection study were used to determine the influence of altering the dietary energy content and crude protein escape on growth, intraruminal protein metabolism, and site of digestion of dry matter, starch, cellulose, hemicellulose, and protein. Dietary energy concentration was increased by tallow, and rumen protein escape was increased by dehydrated alfalfa and distillers dried grains with solubles substituted for soybean meal. Tallow appeared to depress intake and gain, but gain was increased by protein escape from the rumen. Total and particulate digesta crude protein reaching the abomasum was increased by protein escape; however, percentage crude protein digested was decreased in these treatments due to increased acid detergent insoluble nitrogen. Decreasing crude protein solubility decreased ruminoreticular digestion of dry matter, cellulose, hemicellulose, and starch; however, lower intestinal starch digestion compensated for decreased ruminoreticular digestion. In a third study, with growing steers and heifers, corn gluten meal provided the escape protein and soybean meal the degradable protein. Total and average daily gain were greater for the corn gluten meal diet, but intake was not influenced by energy concentration or protein escape.     

Amino acids in plasma and duodenal digesta and plasma growth hormone in cows fed varying amounts of protein of differing degradability

Eighty-four Holstein cows in early lactation fed diets varying in protein percent (11, 14, and 17% crude protein) and degradability in the rumen (normal and heated soybean meal) were sampled for effects on amino acids and growth hormone in blood plasma, and amino acid profiles in the duodenal digesta. Essential and branched chain amino acids in plasma increased as protein and amount of protected protein in the diet increased. These changes were accompanied by decreased concentrations of nonessential amino acids. Plasma growth hormone was highest at low protein (11.3%) probably because of decreased intakes on this diet. Molar percentages of amino acids in duodenal contents were not affected by diet suggesting that our heat-treated soybean meal influenced quantity more than quality of amino acids available for absorption in the small intestines.     

Protein degradation in rumen and amino acid absorption in small intestine of lactating dairy cattle fed heat-treated whole soybeans

Four lactating Holstein cows fitted with rumen cannulae and T-type cannulae in proximal duodenum and terminal ileum were used to measure protein degradation in the rumen and amino acid flow and absorption in the small intestine. Soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149 degrees C provided 50% of the protein in diets that contained 51% grain, 36% corn silage, and 13% alfalfa hay (dry matter). Spot samples of digesta were collected from duodenum and ileum during 96 h, and lanthanum was an indigestible marker to estimate flow and digestibility of nutrients. With diaminopimelic acid as a microbial marker, apparent degradations of dietary crude protein in the rumen were 73, 80, 66, and 60% for diets containing soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149 degrees C. Because of the extensive degradation of protein with the raw soybean diet, less total amino acids reached the duodenum, and because of decrease of availability, absorption from the small intestine (g/day) was lowest with this diet. Feeding diets containing extruded whole soybeans increased availability of total essential amino acids in the small intestine compared with diets containing soybean meal and whole soybeans. Absorption from the small intestine (g/day and percent entering) of individual amino acids was generally higher for extruded whole soybean diets.     

Effect of inoculum preparation and dietary energy on microbial numbers and rumen protein degradation activity

Chilling of whole rumen contents prior to preparation of strained rumen fluid enriched with particle-associated microorganisms resulted in rumen inoculum with the highest microbial dry weight, total bacterial counts, and degradation rates for casein and soybean meal. Strained rumen fluid, whole rumen contents blended with strained rumen fluid, chilled strained rumen fluid, and strained rumen fluid plus particle-associated microorganisms were lower in bacterial counts and microbial dry weight. Except for strained rumen fluid plus particle-associated microorganisms, protein degradation rates were also lower. Three ruminally cannulated cows were used in a 3 X 3 Latin square experiment to determine the effect of diet on rumen microbial numbers and protein degradation rates. Cows were fed the following diets ad libitum: 1) 100% alfalfa hay (20.7% crude protein); 2) 63% alfalfa hay and 37% corn-soybean meal concentrate (18.2% crude protein); and 3) 37% alfalfa hay and 63% corn-soybean meal concentrate (15.1% crude protein). Diet 3 yielded rumen contents with the highest concentration of microbial dry weight, total and viable bacterial counts, total protozoal counts, and fractional degradation rates for casein and bovine serum albumin. However, degradation rate per unit microbial dry matter was not altered by diet.     

Preparation, nutrient composition and digestibility of fermented shrimp head silage

Raw heads of the river prawn, Macrobrachium vollenhovenii, were fermented with Lactobacillus plantarum at 30 °C using molasses or cassava starch as the carbohydrate source. After incubation for 7 days, a desirable and stable pH < 4.5 was attained, and the carbohydrate source did not affect non-protein nitrogen (NPN) content or the proximate composition of the liquid silage after 30 days incubation. Hydrolysed feather meal, poultry by-product meal or soybean meal, used as alternative filler, was blended with the liquid silage (85:15, w/w) and solar-dried. The dried shrimp head silage meals were incorporated as protein supplements into pelleted semi-purified diets for catfish, Clarias gariepinus. Apparent digestibility coefficients of dry matter, crude protein, gross energy and essential amino acids in the silage by catfish fingerlings was high (> 70%). It was concluded that dried fermented fish silage is suitable and has a potential as a protein feedstuff in fish diets.     

Protein sources evaluated for ruminating Holstein calves

Fifty calves were fed a basal diet of 11.6% crude protein or one of four diets (15.5% crude protein) containing added soybean meal, corn gluten meal, cottonseed meal, or fish meal. Diets were calculated 75% total digestible nutrients. Body weight gain increased an average of 17% with added protein. Fish meal and soybean meal generated highest rates of gain. Ruminal ammonia-nitrogen was higher for soybean meal and cottonseed meal than other diets, indicating greater rates of degradability. Molar proportions of rumen volatile fatty acids were not different among diets, but concentration was lower for fish meal. Serum urea nitrogen was lowest for the basal and fish meal diets. Microbial nitrogen in the abomasum was 33.6% of total nitrogen for corn gluten meal and 42.8% for soybean meal. Apparent dry matter and nitrogen digestibilities were greater for corn gluten meal and fish meal diets than for soybean meal or cottonseed meal diets. Rumen degradability of feedstuffs, as determined by dacron bag technique, ranged from 38.1% for corn gluten meal to 71.3% for soybean meal. Degradability of mixed diets reflected those of the protein supplement present in each diet except for diet containing cottonseed meal. Fish meal and soybean meal were better protein sources for growth of ruminating calves than were corn gluten meal or cottonseed meal.     

Protein fractionation byproduct from canola meal for dairy cattle

Fiber-protein is a byproduct arising from a process for fractionating high-quality protein from canola meal. The objective of this study was to evaluate the fiber-protein fraction by examining the chemical profiles, rumen degradation, and intestinal digestive characteristics and determining the nutritive value of the fiber-protein fraction as dietary components for dairy cattle in comparison with commercial canola meal and soybean meal. Available energy values were estimated based on National Research Council guidelines, whereas total true protein content potentially absorbable in the small intestine (DVE) were predicted using the predicted DVE/degraded protein balance (OEB) model. The results show that fiber-protein was a highly fibrous material [neutral detergent fiber (NDF): 556; acid detergent fiber (ADF): 463; acid detergent lignin: 241 g/kg of dry matter (DM)] compared with canola meal (NDF: 254; ADF: 212; acid detergent lignin: 90 g/kg of DM) due to the presence of a higher level of seed hulls in fiber-protein. Compared with canola meal, fiber-protein contained 90 g/kg of DM less crude protein (CP), 25% of which consisted of undegradable acid detergent-insoluble CP. Most of the ruminally undegradable nutrient components present in canola meal appeared to be concentrated into fiber-protein during the manufacturing process and, as a result, fiber-protein showed a consistently lower effective degradability of DM, organic matter, CP, NDF, and ADF compared with both canola meal and soybean meal. Available energy content in fiber-protein contained two-thirds of that of canola meal. The DVE was one-third that of soybean meal and one-fifth that of canola meal [DVE value: 58 vs. 180 (soybean) and 291 g/kg of DM (canola meal)]. The OEB value of fiber protein was positive and about half of that of soybean and canola meal [OEB value: 74 vs. 162 (soybean) and 137 g/kg of DM (canola meal)]. Fiber-protein can be considered as a secondary source of protein in ruminant feed.     

Effect of source of rumen-degraded protein on production and ruminal metabolism in lactating dairy cows

Twenty-eight (8 with ruminal cannulas) lactating Holstein cows were assigned to seven 4 × 4 Latin squares in a 16-wk trial to study the effects on production and ruminal metabolism of feeding differing proportions of rumen-degraded protein (RDP) from soybean meal and urea. Diets contained [dry matter (DM) basis] 40% corn silage, 15% alfalfa silage, 28 to 30% high-moisture corn, plus varying levels of ground dry shelled corn, solvent- and lignosulfonate-treated soybean meal, and urea. Proportions of the soybean meals, urea, and dry corn were adjusted such that all diets contained 16.1% crude protein and 10.5% RDP, with urea providing 0, 1.2, 2.4, and 3.7% RDP (DM basis). As urea supplied greater proportions of RDP, there were linear decreases in DM intake, yield of milk, 3.5% fat-corrected milk, fat, protein, and solids-not-fat, and of weight gain. Milk contents of fat, protein, and solids-not-fat were not affected by source of RDP. Replacing soybean meal RDP with urea RDP resulted in several linear responses: increased excretion of urinary urea-N and concentration of milk urea-N, blood urea-N, and ruminal ammonia-N and decreased excretion of fecal N; there was also a trend for increased excretion of total urinary N. A linear increase in neutral detergent fiber (NDF) digestibility, probably due to digestion of NDF-N from lignosulfonate-treated soybean meal, was observed with greater urea intake. Omasal sampling revealed small but significant effects of N source on measured RDP supply, which averaged 11.0% (DM basis) across diets. Increasing the proportion of RDP from urea resulted in linear decrease in omasal flow of dietary nonammonia N (NAN) and microbial NAN and in microbial growth efficiency (microbial NAN/unit of organic matter truly digested in the rumen). These changes were paralleled by large linear reductions in omasal flows of essential, nonessential, and total amino acids. Overall, these results indicated that replacing soybean meal RDP with that from urea reduced yield of milk and milk components, largely because of depressed microbial protein formation in the rumen and that RDP from nonprotein-N sources was not as effective as RDP provided by true protein.     

Protein quality of some Nigerian feedstuffs. I. Chemical assay of nutrients and amino acid composition

The nutrient and amino acid composition of a range of Nigerian feedstuffs were studied by chemical analysis and column chromatography for amino acids. Nearly all feedstuffs studied showed low crude fibre value except the palm kernel meal and the African locust bean seeds which gave high values, range 8.1 to 12.3% and 8.76 to 12.64%, respectively. All the animal protein concentrates studied, namely, skim milk powder, blood meal and fish meal showed desirable feedstuff characteristics such as a low crude fibre content, high crude protein content and fairly high gross energy values, lysine, methionine and tryptophan were the amino acids in shortest supply in most of the feedstuffs.     

Ruminal digestion by dairy cows grazing winter oats pasture supplemented with different levels and sources of protein.

Six Holstein cows fitted with ruminal cannulae were used in two simultaneous 3 x 3 Latin squares to study the effects of protein supplements on ruminal fermentation and in situ crude protein degradability. Cows rotationally grazed a winter oats (Avena sativa L.) pasture and were supplemented with one of three concentrate supplements: 1) low protein sunflower meal (L-SM); 2) high protein sunflower meal (H-SM); or 3) high protein feather meal (H-FM). Concentrates (6.5 kg/d) were offered in equal portions twice daily during milking. Ruminal pH and total volatile fatty acids concentration were unaffected by treatments. Supplementation with L-SM and H-FM decreased ruminal NH3-N concentration compared with H-SM. The concentrate with feather meal had lower effective rumen degradability of crude protein than concentrates containing sunflower meal. Effective rumen degradability of crude protein of pasture averaged 82.7%. Thirty-six multiparous Holstein cows (71 d in milk) were used in a complementary experiment to study the effect of treatments on intake, milk yield, and milk composition. Pasture (13.2 kg/d) and total (19.6 kg/d) dry matter intake (estimated using Cr2O3 as fecal marker) and milk yield (20.5 kg/d) were unaffected by level or source of protein supplemented. Intake of rumen undegradable protein in grazing dairy cows was higher when the amount of sunflower meal was increased or when feather meal was used in the supplement. However, higher rumen undegradable protein intake did not increase milk production, suggesting that rumen undegradable protein was not limiting for cows on pasture producing less than 22 kg of milk.