复合菌固态生物转化啤酒糟发酵条件优化的研究

利用黑曲霉、绿色木霉、热带假丝酵母三菌株对啤酒酿造下脚料———啤酒糟进行固态发酵转化,在优化的培养基基础上,通过单菌种发酵试验,对发酵接种量、培养方式、菌种配比等进行优化;确定最佳的固态生物转化啤酒糟的发酵条件:菌种配比为,黑曲霉∶绿色木霉∶酵母=2∶1∶1,接种方式为先接黑曲霉、绿色木霉,24h后接酵母。经29℃,200r/min发酵5d得到的产品,具有多种酶活性,酸性蛋白酶酶活力达3540U/g(干基)、纤维素酶活力达432U/g(干基)、糖化酶活力达190U/g(干基),真蛋白质含量升高11.8%。     

好食脉孢菌固体发酵产植酸酶条件的优化

为了扩大植酸酶的来源、优化植酸酶的廉价生产方法,试验以醋糟为培养基的主要成分,以植酸酶活性为测定指标,通过单因素和正交试验确定好食脉孢菌固体发酵产植酸酶的培养基组成和培养条件。结果表明:250 mL三角瓶装干醋糟5 g,添加8%麸皮,料水比为1∶3,培养基初始pH值为5.5,接种量为每克干物质基础接入2×10~5个孢子,培养温度为28℃,培养时间为72 h,优化后植酸酶活性达到127.13 U/g,较优化前(47.59 U/g)提高了约3倍。     

紫红曲霉M-4液态发酵产孢子工艺优化

采用单因素试验和响应面方法对紫红曲霉M-4液态发酵产孢子的培养基成分和培养条件等因素进行优化。结果表明:马铃薯浸粉为最佳氮源,其最适添加量为0.4 g/100 mL;葡萄糖为最佳碳源,其最适添加量为2.0 g/100 mL;培养基最适pH值为自然条件下的pH值(6.72);培养基最佳装液量为120 mL(500 mL锥形瓶);添加2.0 g/100 mL CaCO3的培养基中菌株发酵产孢子数提高较为明显;最佳传代次数为2代,当菌株培养时间达到72 h时,菌株产孢子数达到最大。进一步通过响应面方法分析得到影响紫红曲霉M-4液态发酵产孢子数3个主要因素的优化条件为马铃薯浸粉添加量0.38 g/100 mL、葡萄糖添加量2.2 g/100 mL、培养时间6.5 d,此条件下紫红曲霉M-4最大产孢子数为(7.47±0.15)×10~6 CFU/mL,接近理论预测值(7.53±0.31)×106 CFU/mL,实验平均误差为0.79%。优化后紫红曲霉M-4产孢子数较优化前提高30.13倍,菌株单位体积产孢子能力得到大幅度提升。     

木聚糖酶固态发酵工艺及酶学特性研究

筛选出一株高产木聚糖酶的菌株U6-5,菌体固态发酵产酶条件的研究表明,最佳发酵培养基配方为:麸皮50g、花生壳粉30g、玉米芯粉20g、NH4NO30.5g、水110ml,每克原料接种量为3.05×105个孢子,最适发酵温度28～30℃,在此培养条件下发酵26～28h,木聚糖酶酶活达到6105U/g。该木聚糖酶具有较高的耐热、耐储藏性能。     

蘑菇下脚料中提取木霉分解啤酒糟中纤维素的试验研究

为提高啤酒糟中纤维素的利用率,以啤酒糟作为原料,利用从蘑菇下脚料中提取的木霉在不同添加量、发酵时间、温度及p H条件下分解纤维素单因素试验,在此基础上进行L9(34)正交试验优化。结果表明:在单因素试验中,木霉分别在27℃,p H 5.0,发酵时间2 d,木霉添加量0.030 g(每5 g干啤酒糟)时分解率最高。正交试验的最佳条件是:在发酵温度27℃、发酵时间3 d、发酵p H 5.0和木霉添加量为0.005 g(每5 g干啤酒糟)的组合条件下,分解纤维素的量为7.13%,影响顺序为发酵p H发酵时间发酵温度木霉添加量。试验说明,从蘑菇下脚料中提取的木霉能够较好地分解啤酒糟中的纤维素。     

枯草芽孢杆菌YT168-6产抗菌肽sublancin的发酵工艺优化及培养基筛选的研究

研究旨在探索枯草芽孢杆菌YT168-6产抗菌肽sublancin的最适发酵条件和最适培养基组成,以期提高发酵液中sublancin含量。试验先通过单因素试验筛选出最适发酵条件,确定发酵培养基需要的无机盐、碳源、氮源,再通过正交试验、最陡爬坡试验、Box-Behnken设计的响应面分析方法确定最适发酵培养基组成。结果表明：枯草芽孢杆菌YT168-6产抗菌肽sublancin的最适发酵条件为菌种接种量1.0%、发酵温度37℃、发酵液初始pH 7.0;最适发酵培养基为K₂HPO₄ 5 g/L、KH₂PO₄ 5 g/L、MgSO₄ 10 g/L、可溶性淀粉30.2 g/L、蛋白胨23.6 g/L、玉米浆18.2 g/L;优化后sublancin产量由756 μg/mL提到1 581 μg/mL,是优化前的2.09倍。综上所述,本研究所筛选的最适发酵条件和最适培养基可为枯草芽孢杆菌YT168-6菌株工业化生产sublancin提供技术参考。     

混菌固态发酵啤酒糟生产蛋白饲料的研究

对啤酒糟资源的更深层开发利用,提高其饲喂效价,是缓解我国蛋白质资源短缺的有效途径之一。通过单因素试验和正交优化试验,确定混菌种发酵啤酒糟生产高蛋白饲料的最佳发酵条件啤酒糟与豆粕配比为7:3,接种量为20%,硫酸铵添加量为0.5%,尿素添加量为0.5%,发酵时间为1d。在此条件下,真蛋白达到39.13%。     

脆壁克鲁维酵母生产乳糖酶发酵条件的优化

通过试验研究了一株产乳糖酶脆壁克鲁维酵母的发酵培养基成分及培养条件,最终确定了该株酵母的最佳发酵培养条件.结果表明,此株脆壁克鲁维酵母发酵生产乳糖酶的最佳培养基成分为:乳糖4%,酵母粉3%,MnCl2 1mmol/mL;最佳培养条件:接种量10%,温度28°C,初始pH 7-7.5,摇床转数180 r/min,培养时间36 h.在此条件下培养,乳糖酶活力达1100 u/mL或4140 u/g干菌体.     

利用糖糟与啤酒糟生产蛋白饲料的研究

以糖糟和啤酒糟为原料,接入酵母菌,生产蛋白饲料。实验结果表明:在糖糟70%、啤酒糟30%的配比条件下,固态法发酵60h,发酵温度30℃,每克发酵基质中可得酵母95亿个。发酵基质粗蛋白从25%提高到36%,得到粗蛋白含量很高的优质蛋白饲料。     

以白酒糟为基质进行酵母培养物的研究

为降低酵母培养物的生产成本,并实现白酒糟的资源化无污染化利用,试验以廉价的白酒糟为主要基质,接种酿酒酵母,进行酵母高密度固体发酵后,在此固体基质上进行酵母自溶处理,摸索酵母在白酒糟固体培养基中增殖后的最佳自溶条件,最终确定了在实验室条件下以白酒糟为基质生产酵母培养物的工艺条件:调整经酵母高密度发酵的固体酒糟基质初始p H值为6,向其中添加助溶剂:6%(w/w湿糟)的Na Cl溶液,0.04%(w/w湿糟)木瓜蛋白酶溶液以及9%(v/w湿糟)体积分数为95%的助溶剂无水乙醇,控制助溶剂添加总体积与酒糟干基总质量的体积质量比为1??1,搅拌分散,保持55℃自溶36 h,而后烘干粉碎制得成品。酵母高密度发酵后的白酒糟经自溶处理后产品氨态氮含量达到3.83 mg/g干糟。     

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.     

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.     

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.     

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

Tropical Animal Health and Production -     

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.     

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.     

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