甜菜碱促蛋鸡产蛋的内分泌作用机制

将512和300日龄罗曼蛋鸡随机分为2组，分别饲喂添加甜菜碱0、800mg/kg的2种饲粮，于试验30、80d采血和屠宰，探讨了甜菜碱保产蛋的内分泌作用机制。结果显示，日粮中添加甜菜碱30、80d，均可显著提高产蛋鸡腺垂体和血清中FSH、LH含量（P＜0．05或P＜0．01）；显著提高血清中T3、雌二醇（E2）、孕酮（P4）的含量（P＜0．05或P＜0．01）；显著提高下丘脑和腺垂体中cAMP含量（P＜0．05或P＜0．01）。日粮中添加甜菜碱80d，可显著提高产蛋鸡血清中甲状旁腺激素（PTH）含量（P＜0．05或P＜0．01）。日粮中添加甜菜碱对血清中T4含量无明显影响。     

生物素对肉仔鸡免疫器官的发育、机体免疫功能和神经内分泌激素的影响

将400只1日龄AA肉仔鸡随机分成4个处理，每个处理5个重复，每个重复20只鸡（公母各半）；基础日粮为小麦-酪蛋白型日粮，在基础日粮中分别添加0．30、0．90和2．7mg／kg3个水平的生物素，包括对照组共4种日粮处理。试验结果表明：（1）添加生物素可促进免疫器官的发育，提高其质量指数；提高了血清中新城疫抗体滴度和IgG水平，0．9mg／kg和2．7mg／kg处理组的新城疫抗体滴度显著高于对照组和0．3mg／kg处理组（P＜0．05），2．7mg／kg处理组的IgG水平显著高于对照组（P＜0．05）；（2）添加生物素显著提高了血液中B淋巴细胞的转化效率（P＜0．05）和脾脏中T淋巴细胞（P＜0．05）和B淋巴细胞的转化效率（P＜0．05）；显著降低了血液中表达CD3^＋的细胞含量（P＜0．05），其中2．7mg／kg处理组极显著低于对照组和0．3mg／kg处理组（P＜0．05）；显著降低了脾脏中表达CD3^＋、CD4^＋和CD8^＋的细胞含量（P＜0．05），其中2．7mg／kg处理组显著低于对照组和0．3mg／kg处理组（P＜0．05）；（3）添加生物素后，血清甲状腺素T4、三碘甲状原氨酸T3、生长激素和皮质醇水平呈上升趋势（P＞0．05）。     

酵母铬对热应激肉鸡免疫功能和胴体品质的影响

选用14日龄AA肉仔鸡216只,随机分为6个处理组,每组设3个重复,每重复12只鸡,在基础日粮中分别添加铬0．0（对照）、1．0、2．0、3．0、4．0和5．0mg／kg,试验期4周,测定28d、42d时的免疫器官指数、外周血淋巴细胞转化率以及21d、28d、35d、42d血清新城疫抗体效价和42d胴体品质指标。结果表明：3．0、4．0、5．0mg／kg铬添加水平能够显著提高热应激肉鸡胸腺指数（P〈0．05）;3．0、4．0mg／kg铬添加水平能够显著提高肉鸡血清新城疫抗体效价（P〈0．05）;4．0、5．mg／kg铬添加水平能够显著提高热应激肉鸡28d和42d外周血淋巴细胞转化率（P〈0．05）;日粮添加CrY对热应激肉鸡的屠宰率、半净膛率、全净膛率均未产生显著影响（P〉0．05）;3．0mg／kg铬添加组腹脂率显著低于对照组（P〈0．05）。因此,日粮添加酵母铬可以提高热应激肉鸡免疫器官指数和血清新城疫抗体效价,刺激外周血淋巴细胞的增殖,有改善胴体品质的趋势。     

免疫增强剂硒对雏鸡免疫功能的影响

300只1日龄南海黄雏鸡随机分为5组，Ⅰ－Ⅳ组为加硒试验组，Ⅴ组为不加硒对照组。全部试验鸡均饲喂不缺硒饲料（含硒0．18mg/kg)，并以饮水方式进行新城疫首免和2免。Ⅰ、Ⅱ、Ⅲ、Ⅳ组分别于2次免疫前2d起连续3d以亚硒酸钠饮水给硒0．25、0．5、0．75、1．0mg/kg。结果表明，各组平均血清硒含量变化与饮水给硒剂量一致；Ⅰ－Ⅳ组的新城疫HI抗体滴度显著或极显著地高于Ⅴ组（P＜0．05或P＜0．01）；Ⅲ、Ⅳ组体重显著或极显著地高于Ⅴ组（P＜0．05或P＜0．01）；各加硒试验组特别是Ⅲ组在红细胞Ⅰ型补体受体（CR1）活性较Ⅴ组高；各组免疫器官指数未出现显著性差异。     

甜菜碱对肉鸡生长和肉质的影响试验

选用288羽29日龄艾维茵肉鸡，按饲养试验要求分成4组（每组3个重复），分别喂以添加0，500，750，1000mg/kg甜菜碱的相同饲粮，进行为期21天的饲养试验。在研究甜菜碱对肉鸡生长影响的基础上，选择剂量最佳组进行屠宰取样，测定肌肉中肌酸、肌苷酸和肌红蛋白含量等指标，探讨甜菜碱对肉鸡肉质的影响。结果表明：（1）1000mg/kg剂量组效果最佳，日增重提高7．20％（P＜0．05），料重比降低6．81％（P＜0．05）；（2）在饲粮中添加1000mg/kg甜菜碱显著改善了肉质，肌肉中肌酸、肌苷酸和肌红蛋白含量分别增加了17．28％（P＜0．01）、26．92％（P＜0．01）和9．15％（P＜0．05）。     

果寡糖对固始鸡免疫功能的影响

试验旨在研究果寡糖对固始鸡免疫功能的影响,并确定果寡糖的最佳添加剂量。选用1日龄固始鸡公雏150只。分成5组,1组为对照组．其余的4组为试验纽,对照组不加果寡糖,其他4组的果寡糖添加水平分别为3mg／kg、5mg／kg、7mg／kg和9mg／kg。测定胸腺、脾脏、法氏囊重量和指数、血清新城疫（NDV）抗体效价、血清溶菌酶含量等指标。试验结果表明：①21日龄时,果寡糖（FOS）组的胸腺和法氏囊重量、指数显著高于对照组（P〈0．05）;42日龄时,果寡糖（FOS）组的法氏囊重量、指数显著高于对照组（P〈0．05）。②在二免7d和14d时,果寡糖（FOS）组的血清新城疫抗体效价显著高于对照组（P〈0．05）。③21和42日龄时,果寡糖（FOS）组的血清溶菌酶含量比对照组略高,但无显著性差异（P〉0．05）。④日粮中添加7mg／kg果寡糖（FOS）对提高固始鸡法氏囊重量和指数、血清新城疫抗体效价、血清溶菌酶含量具有最佳效果。这说明日粮中添加果寡糖能够提高固始鸡器官免疫、体液免疫免疫和非特异性免疫功能。     

果寡糖对肉鸡生长、肠道菌群和肠形态的影响

研究了饲粮中分别添加0、2000、4000、6000mg/kg果寡糖对艾维菌商品代肉鸡生长性能、肠道菌群和肠形态的影响。结果表明：目粮中添加4000mg/kg果寡糖使肉鸡日增重提高了9．53％（P＜0．01），2000、4000mg/kg果寡糖使料重比分别降低了5．09％（P＜0．05）和7．87％（P＜0．05）；4000mg/kg果寡糖使盲肠中双歧杆菌和总厌氧菌数分别增加了257．65％（P＜0．05）和100．00％（P＜0．05），使梭菌数下降了79．36％（P＜0．05）；2000、4000mg/kg果寡糖使盲肠中乳酸杆菌数分别增加了45．73％（P＜0．05）和67．97％（P＜0．01），使大肠杆菌数分别下降了75．71％（P＜0．05）和71．35％（P＜0．05）；4000和6000mg/kg果寡糖使盲肠中乙酸、丁酸和总短链脂肪酸含量分别提高了23．25％（P＜0．05）和26．08％（P＜0．05）、144．36％（P＜0．05）和202．97％（P＜0．01）、47．08％（P＜0．01）和58．31％（P＜0．01）；2000、4000和6000mg/kg果寡糖使盲肠中丙酸含量分别提高了45．27％（P＜0．05）、73．22％（P＜0．01）和89．37（P＜0．01）；4000、6000mg/kg果寡糖使盲肠上皮黏膜腺窝深度和细胞密度分别提高了22．62％（P＜0．05）和25．72％（P＜0．01）、19．28％（P＜0．05）和23．07％（P＜0．05）。     

甜菜碱替代日粮中合成单体蛋氨酸对海兰福鸡产蛋后期生产性能的影响

利用开产400日龄后（约554日龄）的海兰褐蛋鸡720羽,平均分为3组,每组240只共5个重复,研究用甜菜碱盐酸盐,替代日粮中单体蛋氨酸对产蛋后期生产性能的影响。对照日粮中所用氯化胆碱为0．6kg／t,单体合成蛋氨酸量为0．8kg／t,试验日粮是将对照日粮中添加的单体蛋氨酸分别用甜菜碱盐酸盐替代50％和100％,并根据1kg甜菜碱盐酸盐相当于2kg蛋氨酸方式进行替代。结果表明在本试验条件下（无鱼粉含有少量杂粕的日粮,产蛋高峰后期）,用甜菜碱盐酸盐替代日粮中50％或全部单体合成蛋氨酸（按1：2）均可显著（P＜0．01）提高海兰褐蛋鸡产蛋高峰后期产蛋率,而且50％和全部替代组间无显著差异（P＞0．05）。用甜菜碱盐酸盐100％替代蛋氨酸由于破蛋率显著升高,因此平均蛋重也显著低于对照组和50％替代组（平均蛋重由总蛋重和每日产蛋数求得,包括破蛋）。但全期总的产蛋重不论50％或100％替代蛋氨酸组均显著高于对照组。3组饲料的采食量绝对值上差异不大,但甜菜碱替代组的料蛋比均低于对照组（P＜0．01）。上述结果表明,在产蛋高峰后期,甜菜碱盐酸盐在替代50％蛋氨酸或100％替代蛋氨酸可缓解产蛋后期产蛋率的下降,从而提高饲料转化效率。用甜菜碱完全替代单体蛋氨酸时破蛋率提高,但原因不明。因此建议     

维生素C对蛋鸡部分免疫器官指数及新城疫抗体效价的影响

为了探讨不同剂量维生素C（vitamin C,VC）对蛋鸡免疫机能的影响,将240只体重相近的45日龄罗曼褐壳蛋鸡随机分为A、B、C、D、E 5组,每组4个重复,每个重复12只。A组不进行免疫,日粮中也不添加VC,为对照组,B、C、D、E 4组颈部皮下注射新城疫Ι系疫苗进行免疫,并在该4组日粮中分别添加0、250、500、750 mg/kg的VC,分4周测脾脏、胸腺、法氏囊等免疫器官指数及血清中新城疫HI抗体效价。结果显示,添加VC的C、D、E组,蛋鸡脾脏、胸腺等免疫器官指数均显著（P＜0.05）或极显著（P＜0.01）高于B组,法氏囊指数在第21、28天显著高于B组（P＜0.05）,新城疫HI抗体效价极显著高于B组（P＜0.01）,且以日粮中500 mg/kg的VC添加量效果最好。由此可见,在鸡的日粮中适当添加VC能促进脾脏、胸腺等免疫器官的生长发育,显著增强免疫系统合成分泌抗体的能力,从而提高鸡体的免疫机能。     

甘露寡糖与抗生素对肉鸡生产性能及免疫机能的影响

选择11日龄广东岭南黄鸡400只，随机分成2组，即对照组（添加4mg/kg的黄霉素）和试验组（添加1mg/kg的甘露寡糖添加剂）。每组设4个重复，每个重复50只鸡。试验期45d，试验结果表明，日增重，日采食量和料重比，试验组较对照组略有提高。分别提高0．60，1．62和0．88％，但差异并不显著（P＞0．05）。新城疫抗体效价，试验组比对照组降低了13．54％。差异不显著（P＞0．05）；IgA，IgG，试验较对照组分别提高了37．72％和43．59％，但差异不显著（P＞0．05）；IgM，试验组较对照组显著提高了95．77％，差异显著（P＜0．05）。试验研究表明，在肉鸡生产中，用甘露寡抗生素是可行的。     

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