伴大豆球蛋白酶解肽抑菌活性研究

建立伴大豆球蛋白酶解产生抑菌肽的最适条件,对酶解产物进行分离纯化后进一步测定其抑菌活性。采用复合风味蛋白酶水解伴大豆球蛋白,测定不同时间的酶解液对大肠杆菌和金黄色葡萄球菌的抑菌活性。结果显示:2 h水解产生的酶解肽具有抑菌活性,其对大肠杆菌和金黄色葡萄球菌的最小抑菌浓度分别是2.6和3.2 mg/mL。2 h水解液经Sephadex-G15分离纯化,采用平板计数法鉴定各组分。结果显示:CP2组分对大肠杆菌具有显著的抑制作用(P<0.05)。本研究证明伴大豆球蛋白的复合风味蛋白酶酶解肽具有一定的抑菌活性。     

灌喂大豆蛋白胃蛋白酶酶解物对大鼠免疫功能的影响

经碱提酸沉法制备大豆蛋白,胃蛋白酶水解,茚三酮法测定水解液水解度,系统观察了灌喂1mL的5mg/mL的大豆蛋白酶解物对大鼠免疫功能的影响。结果表明:大豆蛋白水解液含氮量为(2.15±0104)mg/mL,水解度为14.49%,平均肽链长度为6.9。灌喂21d后,发现胸腺、脾脏指数较对照组分别上升了24%(P<0101)和32%(P<0101);灌喂大豆蛋白酶解物能显著促进大鼠腹腔巨噬细胞吞噬活性;该组比对照组A570上升67%(P<0101);大鼠外周血淋巴细胞转化明显增强,试验组较对照组上升了82.8%。能显著提高大鼠血清抗体的血凝抑制效价(hemagglutination inhibition titer,HI),试验组比对照组HI值上升了33.3%,差异极显著(P<0101);试验组的肠腔sIgA水平较对照组上升了34.3%,差异极显著(P<0101);灌喂大豆蛋白酶解物能极显著提高血液IL22和Leptin水平。试验结果表明灌喂大豆蛋白酶解物能增强大鼠免疫功能,主要是酶解肽的生物活性的作用结果,并非营养调节作用的结果,酶解物对大鼠消化代谢影响不大。     

饲粮添加芽孢杆菌对感染大肠杆菌K88仔猪脾脏TLRs表达的影响

试验旨在研究饲粮中添加枯草芽孢杆菌对感染大肠杆菌K88仔猪脾脏Toll-样受体(TLRs)表达的影响。选用平均体重(6.8±0.5)kg的去势"杜×长×大"三元杂交公猪8头,随机分为2组,每头猪单栏饲养,对照组饲喂基础饲粮,试验组饲喂基础饲粮+0.1%枯草芽孢杆菌,饲喂期结束时每头猪灌服致病性大肠杆菌K88菌液(每头猪灌服1×1011CFU)。试验结果表明,仔猪采食枯草芽孢杆菌的饲粮,进行大肠杆菌攻毒后,能显著降低脾脏TLR2和TLR4的表达水平(P0.05)。结果提示,仔猪采食添加枯草芽孢杆菌的饲粮,在致病性大肠杆菌K88感染时,能降低脾脏TLRs的表达水平,调节机体炎症反应。     

伴大豆球蛋白水解肽体外抑菌活性试验

大豆贮藏蛋白主要由大豆球蛋白和伴大豆球蛋白组成[1-2],大豆肽是大豆蛋白质酶解的产物,具有多种生物活性作用。伴大豆球蛋白水解肽作为一种植物蛋白来源的多肽,已得到人们的广泛关注。而其抗菌活性研究方面的报道较少,并且很久以来被     

伴大豆球蛋白水解肽的制备及其对沙门氏菌增殖的影响

利用等电沉淀和盐析的方法,获得大豆球蛋白,并通过Sepharose-CL-6B凝胶柱层析分离纯化,得到单一组分,经SDS-PAGE鉴定为纯化的7 S伴大豆球蛋白,然后将其用胃蛋白酶水解得到伴大豆蛋白水解肽(PTC)。通过96孔细胞培养板2倍稀释法,对不同浓度的伴大豆球蛋白胃蛋白酶水解肽(6,3,1.5和0.75 mg/mL)与沙门氏杆菌共同培养,观察了伴大豆蛋白水解肽对沙门氏杆菌增殖的影响。结果发现,添加不同浓度的伴大豆蛋白水解肽可以影响沙门氏菌的增殖,其中6 mg/mL和3 mg/mL的PTC对沙门氏菌的生长产生明显的抑制作用,1.5 mg/mL的PTC对沙门氏菌作用不明显,而0.75 mg/mL的PTC有微弱的促进作用,表现一定的营养作用。     

芬氏纤维微菌对雏鸭盲肠微生物的影响

为研究芬氏纤维微菌(Cellulosimicrobium funkei)对雏鸭盲肠微生物菌群的影响以及该菌对AFB_1暴露雏鸭盲肠微生物菌群的影响。选取100只健康、体重相近的1日龄樱桃谷肉鸭,随机分为5个组,每组4个重复,每个重复5只雏鸭。每组均饲喂标准日粮,对照组经口灌服1 ml无菌LB培养基,每天灌胃1次,连续灌胃14 d;试验组1灌服1 ml C.funkei菌液(1×108cfu/ml),每天灌胃1次;试验组2灌服1 ml C.funkei菌液(1×10~(10)cfu/ml),每天灌胃1次,连续灌胃7 d,第8 d停止灌服菌液,只灌服1 ml无菌LB培养基;试验组3按照0.1 mg/(kg·BW)的量灌服AFB_1溶液+1 ml无菌LB培养基,每天灌胃1次;试验组4按照0.1 mg/(kg·BW)的量灌服AFB_1溶液+1 ml C.funkei菌液(1×108cfu/ml),每天灌胃1次,连续灌胃14 d。预饲期3 d,试验期14 d。结果表明,给雏鸭灌服低剂量C.funkei菌液可有效降低雏鸭盲肠内容物中大肠杆菌的数量,对乳酸菌和双歧杆菌数量无影响,灌服高剂量C.funkei菌液使雏鸭盲肠内容物中总需氧菌和总厌氧菌数量显著升高。灌服AFB_1的雏鸭盲肠内容物中大肠杆菌的数量显著升高,乳酸菌数量显著降低,而对AFB_1暴露雏鸭灌服芬式纤维微菌,可显著降低大肠杆菌和总需氧菌的数量,在一定程度上改善了盲肠微生物区系。     

大豆抗原蛋白对小鼠肠上皮细胞的影响

大豆中所含的抗原蛋白是引起幼龄动物发生过敏反应的重要原因之一。研究以自备分离纯化大豆球蛋白和β-伴球蛋白作为试验材料,以原代培养小鼠肠上皮细胞作为试验模型,研究0、1、5和10mg/mL纯化大豆球蛋白和β-伴球蛋白对小鼠肠上皮细胞完整性和免疫的影响。结果表明:超过5mg/mL大豆球蛋白和β-伴球蛋白能破坏小鼠肠上皮细胞完整性,抑制上皮细胞增殖。显著提高培养液乳酸脱氢酶(LDH)和谷草转氨酶(GOT)水平。大豆球蛋白和β-伴球蛋白能显著提高体外培养的小鼠肠上皮细胞炎性细胞因子(白介素-2(IL-2)、白介素-6(IL-6)、白介素-8(IL-8))的分泌,促使其发生过敏反应。     

小鼠生长迟缓模型的建立及指标评价

试验旨在通过灌服细菌上清、破碎液建立小鼠生长迟缓模型,为开发具有促生长作用的饲料添加剂提供动物模型。培养大肠杆菌K99,离心收集培养上清,取部分细菌悬液进行超声破碎;试验小鼠随机分为4组(对照组、上清组、破碎组、悬液组),对照组灌服0.2 m L生理盐水,另外3组分别灌服等体积细菌培养上清、破碎液及悬液,每日1次,连续灌服15d;观察小鼠精神状态,记录小鼠体重,测定各脏器指数,采用ELISA方法检测各组小鼠血清IL-6和TNF-α的水平。与空白组相比,其余3组小鼠日增重及脾脏指数均显著降低;肺脏指数显著升高;肝脏、胸腺指数及血清IL-6和TNF-α的水平无显著变化。通过灌服大肠杆菌K99培养上清、破碎液及悬液成功建立了小鼠生长迟缓模型,能够为开发具有细菌毒素灭活作用的中药添加剂提供动物模型。     

小肽对山羊氮平衡和营养物质消化率的影响

将8头浏阳黑山羊随机分成4组,其中2组安置十二指肠瘘管,灌注大豆肽与水解氨基酸,按2因素随机化设计,测定灌注与饲喂大豆肽及其水解氨基酸对山羊氮平衡和营养物质消化率的影响.结果表明,从十二指肠灌注小肽组氮沉积显著(P<0.05)高于灌注氨基酸组,极显著(P<0.01)高于饲喂小肽组与氨基酸组,灌注小肽和氨基酸与饲喂小肽和氨基酸氮沉积分别为6.98和5.81 g/d与5.42和5.09 g/d,饲喂小肽较饲喂游离氨基酸能显著(P<0.05)提高氮沉积;饲喂小肽与灌注小肽能显著地提高能量和钙的消化率.     

植物乳酸菌发酵对大豆球蛋白和β-伴大豆球蛋白免疫活性及水解度的影响

本试验通过植物乳酸菌对豆粉进行液态发酵,在发酵24,36,48,60,72 h时采集发酵样品进行水解度和免疫活性的检测,结果表明:(1)48 h为植物乳酸菌发酵豆粉的最佳时间,可去除71.08%的β-伴大豆球蛋白和64.22%的大豆球蛋白的免疫活性(P＜0.01),对β-伴大豆球蛋白的去除程度显著高于大豆球蛋白(P＜0...     

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.     

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.     

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.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

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

Tropical Animal Health and Production -