豆粕固态发酵及酶解制备小分子肽的研究

本实验以氨基酸态氮生成率为考察指标,研究了豆粕原料经米曲霉固态发酵制曲后,所得曲料加水酶解制备活性小分子肽的工艺条件。通过单因素实验对豆粕蛋白的酶解条件进行了筛选,豆粕固态发酵制曲后,曲料底物浓度20%、酶解温度40℃,酶解时间32小时,酶解液氨基酸态氮生成率最优。酶解液经喷雾干燥后,粉样粗蛋白含量52.83%,小分子肽(酸溶蛋白)含量36.16%,氨基酸态氮6.32%,猪仿生蛋白消化率82.26%,具有较高营养价值,为豆粕蛋白的深度开发利用及替代饲料中动物蛋白源选择性奠定理论基础。     

复合酶水解法提取大豆抗氧化肽的工艺优化

为提高脱脂豆粕的利用率,试验选用碱性蛋白酶与风味蛋白酶的组合从脱脂豆粕中提取大豆抗氧化肽,以加酶量(E/S)、温度、p H及时间为自变量,以酶解液对1,1-二苯基-2-三硝基苯肼(DPPH)自由基的清除率为评价指标,在单因素试验的基础上,采用Design-Expert软件,建立DPPH自由基清除率与各因素间的二次多项式模型,确定提取大豆抗氧化肽的最佳提取条件为加酶量(E/S)5%、温度58℃、p H 10及酶解时间3 h,在此条件下,大豆抗氧化肽对DPPH自由基的清除率达到89.94%,与预测值90.69%的相对误差小。回归方程的预测值与试验值差异不显著(P0.05),说明回归模型拟合情况较好。     

酶解豆粕工艺参数的探索和优化

本试验旨在研究酶解参数(料水比、温度、酶添加量和处理时间)对角蛋白酶降解豆粕β-伴大豆球蛋白和大豆球蛋白效果的影响,并以小麦麸为酶解豆粕的辅料探究酶解豆粕干燥速率和干燥后物料结块程度。结果表明:在本试验条件下,25℃、添加6 kg/t角蛋白酶、料水比为5:4、酶解24 h,豆粕中约60%的β-伴大豆球蛋白和37%的大豆球蛋白被降解;65℃恒温干燥后,与纯酶解豆粕相比,添加30%小麦麸的酶解豆粕的干燥速率变化不大,但是干燥后物料结块现象不明显;纯豆粕酶解干燥后,6目大颗粒占总物料含量由0增加至7%,6~18目颗粒占总物料含量由20%增加至40%;添加30%小麦麸的豆粕酶解干燥后,6目大颗粒含量变化不明显,6~18目颗粒含量由25%增加至30%。综上可知,在本试验条件下,酶解豆粕中添加30%小麦麸能够有效降低豆粕中的抗营养因子以及减少在高水分条件下酶解豆粕结块。     

低温脱脂豆粕制备大豆肽生产工艺优化及生物活性探究

利用低温脱脂豆粕,经65%乙醇变性处理后,采用Alcalase碱性蛋白酶酶解豆粕蛋白制备大豆肽。通过单因素试验,考察p H、底物质量分数、酶用量(E/S)和酶解温度等因素对Alcalase碱性蛋白酶酶解豆粕蛋白效果的影响。通过正交试验设计,确定酶解最佳工艺参数:酶解温度60℃,底物质量分数7%,酶用量(E/S)5 300 U/g,p H 9.5,此条件下,蛋白水解度达最大,为21.54%。利用离子交换树脂法进行脱盐浓缩,又分别用改进的亚油酸-硫氰酸钾方法和邻苯三酚法对产品抗氧化能力进行检测。试验结果表明:利用离子交换树脂方法的脱盐率为95.12%,大豆肽清除自由基能力的顺序和抗亚油酸过氧化能力结果基本保持一致。     

角蛋白酶水解豆粕参数优化对营养价值的提升

研究旨在通过优化嗜热厌氧杆菌(Keratinibaculum paraultunense) KD-1角蛋白酶酶解豆粕条件来达到提高豆粕营养价值,改善其功能的目的。以酸溶蛋白含量为指标,采用单因素试验和正交试验优化豆粕酶解条件。结果表明,酶解豆粕的最佳条件为:酶解温度85℃,底物浓度10%,酶解时间3 h。经KD-1粗酶液酶解后,豆粕中的粗蛋白质、酸溶蛋白、游离氨基酸等营养物质含量显著增加(P0.05);脲酶、棉籽糖、水苏糖、大豆球蛋白、β-伴大豆球蛋白、胰蛋白酶抑制因子等6种抗营养因子含量显著下降(P0.05)。结果显示,豆粕经角蛋白酶酶解后,其营养价值显著增加,功能得到了改善。     

双酶法酶解豆粕蛋白最佳工艺条件研究

为了提高豆粕短肽含量,有效促进其吸收利用,试验通过对豆粕蛋白氮溶指数(NSI)的研究选择碱性蛋白酶和风味蛋白酶对其进行酶解,采用正交试验法对酶解条件进行优化。结果表明:碱性蛋白酶酶解豆粕蛋白的最佳酶解条件是p H值11,酶量4 m L,温度50℃,酶解3 h;风味蛋白酶酶解豆粕蛋白的最佳酶解条件是p H值7.0,酶量2.5 g,温度55℃,酶解2 h。经二次酶解后,豆粕蛋白在p H值为7时其三氯乙酸氮溶指数(TCA-NSI)可由原来的8.3%增加到72.3%,短肽含量增加近10倍。说明经碱性蛋白酶和风味蛋白酶降解后将大大提高豆粕蛋白的吸收利用率。     

菌酶协同处理豆粕制备饲用小肽的研究

以小肽含量为指标研究了芽孢杆菌、酵母菌和中性蛋白酶协同发酵、酶解处理豆粕制备饲用小肽的工艺条件。结果表明:菌酶协同处理豆粕的最佳条件为混合菌接种量1.5%、加酶量450 U/g、料水比1∶1.4、发酵温度40℃、发酵时间48 h。在此条件下,豆粕经菌酶协同处理后,小肽含量从11.40 mg/g提高到199.65 mg/g,粗蛋白质含量从47.62%提高到56.72%。     

大豆肽研究进展

大豆肽是大豆蛋白质的水解产物。目前一般以大豆、豆粕或大豆分离蛋白为底物 ,用酶解的方法来制备。大豆肽是平均肽链长度为 2～ 1 0的短肽 (以 2～ 3的低分子肽为主 ) ,还含有少量的游离氨基酸、糖类和无机盐成分 ,分子量以低于 1 0 0 0的为主体 ,主要溶出峰位置在分子量 30 0～ 70 0范围内。大豆肽的分子质量大小、肽链长短以及各种理化性质由所选用的酶类、水解条件和分离方法而定。大豆肽的蛋白质含量为 85 %左右 ,其氨基酸组成几乎完全与大豆蛋白质相同 ,必需氨基酸的平衡良好且含量丰富。与大豆蛋白相比 ,大豆肽具有更好的理化性质如…     

米蛋白肽制备工艺研究及产品营养成分分析

本研究以米渣为原料,通过对米渣进行预处理及限制性酶解后,再对酶解液浓缩后喷雾干燥得到米蛋白肽粉,研究其最佳酶解条件及产物性质.结果表明:(1)最佳酶解工艺条件:用酶量为1%,酶解温度为50℃,固液比为1:5,pH值为8,酶解时间3 h;(2)产物米蛋白肽的蛋白质含量为91.5%,分子质量大部分在3000 Da 以下,短肽含量为77.87%,必需氨基酸含量丰富,是一种优质植物蛋白质资源.     

不同大豆蛋白源饲料饲喂草鱼试验

试验旨在对比不同蛋白源在草鱼饲料中的添加效果。选择平均体质量(45.00±4.02)g的600尾草鱼随机分为5个处理组,每组3个重复,每重复40尾。试验结果表明,大豆酶解蛋白和大豆浓缩蛋白100%替代对照组中鱼粉可显著提高草鱼的特定生长率,而膨化豆粕和豆粕替代鱼粉后,草鱼特定生长率降低,其中豆粕组差异显著。与对照组相比,豆粕、膨化豆粕、大豆酶解蛋白和大豆浓缩蛋白替代鱼粉后,饲料系数均有所提高,其中大豆酶解蛋白组差异不显著。大豆酶解蛋白替代鱼粉,可提高干物质消化率,但蛋白质和脂肪的消化率降低。豆粕替代鱼粉后,干物质、蛋白质和脂肪的表观消化率都降低,其中蛋白质和脂肪的消化率显著降低。大豆浓缩蛋白和膨化豆粕代替鱼粉后,干物质、蛋白质和脂肪消化率均显著降低。豆粕和大豆浓缩蛋白替代鱼粉后,体质量/体长比降低,内脏/体质量和肝胰脏/体质量的比值增加。膨化豆粕替代鱼粉后,体质量/体长的比值显著降低,内脏/体质量的比值和肝胰脏/体质量的比值增加,其中后者显著增加。大豆酶解蛋白替代鱼粉后,体质量/体长、内脏/体质量和肝胰脏/体质量的比值均有所改善,但差异不显著。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.