北京油鸡杂交效果的研究

为培育优质北京油鸡配套系提供理论依据,试验采用北京油鸡纯系(Y系)与北京油鸡合成品系(G系)进行正反杂交,观测亲本及其杂交组合的体尺、外貌性状、生长性能、屠宰性能和肉质性状,并比较各性状的杂种优势。结果表明:Y系与G系的正反交组合不仅在生长性能、屠宰性能及相应的肉质性能上具有显著的杂种优势,而且杂交后代能够很好地保持北京油鸡的外貌特征;在正反交组合中,以Y系为父系、G系为母系的正交组合(YG)表现的更为优秀。说明北京油鸡在优质鸡育种和杂交利用上更适合做父系,以充分利用其优良的遗传品质。     

北京油鸡与贵妃鸡杂交效果研究

本研究以北京油鸡和贵妃鸡为素材,比较北京油鸡♂×北京油鸡♀(YY)、贵妃鸡♂×贵妃鸡♀(GG)、北京油鸡♂×贵妃鸡♀(YG)、贵妃鸡♂×北京油鸡♀(GY)4种组合的外貌、体重、屠宰性能和肉质性状.结果表明:杂交后代凤头、胡须、毛腿、双五趾个体比例分别是99.4％、88.1％、95.2％和72.0％;6～20周体重显著高于贵妃鸡(P＜0.01),16周屠宰率、半净膛率、全净膛率和胸肌率高于北京油鸡(P＜0.01).以北京油鸡为母本的杂交组,同周龄体重有高于北京油鸡为父本杂交组的趋势,且屠宰率和胸肌率较高(P＜0.05),为最佳组合.     

品种、日龄及饲养方式对鸡肉肌苷酸和肌内脂肪含量的影响

本试验旨在研究品种、日龄和饲养方式对鸡肉肌苷酸(IMP)和肌内脂肪(IMF)含量的影响及其互作效应.选取爱拔益加(AA)肉鸡和北京油鸡各240只,每个品种均分笼养和地面平养2种饲养方式,每种饲养方式120只鸡(均为6个重复,每个重复20只),在21和42日龄分别比较2种饲养方式下鸡的胸肌IMP和IMF含量,并分析其脂肪酸组成.结果表明:1)IMP含量北京油鸡显著高于AA肉鸡(P<0.05),42日龄显著高于21日龄(P<0.05),品种和日龄对鸡肉IMP含量的影响存在显著的互作效应(P<0.05);2)IMF含量北京油鸡显著高于AA肉鸡(P<0.05),42日龄显著高于21日龄(P<0.05),笼养显著高于平养(P<0.05),3个因素对鸡肉IMF含量的影响无显著的互作效应(P>0.05);3)脂肪酸含量除C18:2和C24:0为北京油鸡显著高于AA肉鸡(P<0.05)外,其余脂肪酸则为AA肉鸡显著高于北京油鸡(P<0.05);AA肉鸡不饱和脂肪酸含量及其与饱和脂肪酸的比例显著高于北京油鸡(P<0.05);除C18:0、C20:0和C22:0外,品种对其他脂肪酸含量均有显著影响(P<0.05),日龄对脂肪酸含量无显著影响(P>0.05),平养显著降低了饱和脂肪酸含量及其与不饱和脂肪酸的比例(P<0.05);3个因素对鸡肉脂肪酸含量的影响无显著的互作效应(P>0.05).由此可知,北京油鸡鸡肉的IMP和IMF含量以及脂肪酸C18:2和C24:0含量显著高于AA肉鸡,42日龄鸡鸡肉的IMP和IMF含量显著高于21日龄鸡,平养鸡鸡肉的IMF含量、饱和脂肪酸C14:0、C18:0、C20:0和C22:0含量以及饱和脂肪酸与不饱和脂肪酸的比例均显著低于笼养鸡,品种和日龄对鸡肉的IMP含量有显著的交互作用.     

A-FABP和AMPD1基因SNP位点对北京油鸡部分肉质性状的组合效应分析

本研究旨在分析鸡脂肪型脂肪酸结合蛋白(A-FABP)和腺苷一磷酸脱氨酶(AMPD1)基因的SNP位点对鸡肉肌内脂肪(IMF)和肌苷酸(IMP)含量的组合效应.试验以北京油鸡为材料,采用PCR-SSCP技术对A-FABP基因外显子1第51位碱基(P4位点)的C→T突变和AMPD1基因序列第129位(PB位点)的A→G突变进行单基因和多基因组合效应分析.结果表明,P4位点的突变纯合BB基因型和PB位点的突变纯合NN基因型分别是多态位点上IMF和IMP含量的优势基因型;组合效应分析结果表明,在9种组合中,BBNN和BBMN组合基因型个体的组合效应显著,其中BBMN基因型个体的IMF含量、腹脂率(AFP)和平均脂带宽(WFS)比组合前P4位点BB基因型和PB位点MN基因型个体的均值分别增加了7.80%、50.74%和4.92%,组合效应显著(P<0.05),IMP含量比组合前增加了2.53%;2个基因位点间不存在显著的互作效应(P>0.05).因此,可将BB与NN或MN基因型聚合,进行分子标记聚合育种,以辅助选择提高鸡肉IMP和IMF含量.     

广西瑶鸡与青胫黄麻羽新品系配套利用研究

为充分利用地方品种广西瑶鸡种质资源,通过杂交配套提高其生产性能,本研究以Y系(青胫广西瑶鸡)为父本,A系(青胫中速黄麻羽)、D系(青胫矮脚黄麻羽)、E系(青胫羽色偏红)为母本,分别进行杂交组合,杂交后代分别为YA、YD和YE。通过测定杂交后代生产性能、屠宰性能及肉质等性状评价广西瑶鸡杂交利用效果,以期筛选出较好的杂交组合。结果表明:YA的活重、屠体重、半净膛重、全净膛重、胸肌重均显著大于YD与YE(P0.05);在公鸡中,YA的胸肌△pH(pH_(45min)—pH_(24h))显著低于YD和YE(P0.05),酸败速度较慢,YA的腿肌剪切力显著小于YD与YE(P0.05),YA的肌内脂肪含量显著高于YD和YE(P0.05);在母鸡中,YD的胸肌肌内脂肪含量显著高于YA与YE(P0.05),YE的干物质含量显著高于YA与YD(P0.05);在腿肌中,YA的滴水损失显著低于YD与YE(P0.05),3个组合胸肌滴水损失都高于腿肌,胸肌pH都低于腿肌。综上可知,以广西瑶鸡为父本、中速黄麻羽A系为母本配套可有效提高广西瑶鸡的生产性能和屠宰率,并且具有较好的肉品质。     

优质鸡肌内脂肪(IMF)和肌苷酸(IMP)含量与屠宰及肉质性状的相关分析

选取92日龄不同优质新品系鸡50只,分析了肌内脂肪(IMF)和肌苷酸(IMP)含量与屠宰性状和肉质性状的相关性。结果显示:肌内脂肪(IMF)含量与腹脂率的相关系数最高(r=0.3234,P=0.0220),与腿肌率的相关系数达到了显著水平(P<0.05);肌苷酸(IMP)含量与胸肌率的相关系数最高(r=0.3604,P=0.0102)。总体上肌内脂肪(IMF)和肌苷酸(IMP)含量与肉质性状的表型相关较弱,其中肌内脂肪(IMF)含量与水分呈显著水平的表型负相关(P<0.05),肌苷酸(IMP)含量与水分呈显著水平的表型正相关(P<0.05),与pH值的相关系数也达到了显著水平(P<0.05)。     

拜城油鸡与良凤花鸡杂交后体尺测定及分析

为了培育出适合在新疆地区饲养的优质土鸡品种,试验采用拜城油鸡公鸡与良凤花鸡母鸡(麻羽)进行杂交,得到杂交一代(油麻鸡F1代),选取油麻鸡F1代青脚母鸡与拜城油鸡公鸡回交得到杂交二代(油麻鸡F2代),再选用性状突出的油麻鸡F2代母鸡与F2代高脚公鸡本交得到杂交三代A(油麻鸡F3 A)型,用油麻鸡F2代母鸡与良凤花公鸡杂交得到杂交三代B(油麻鸡F3 B)型,分别测定油麻鸡F3 A型和B型的体尺性状并进行比较。结果表明:油麻鸡F3 A型和B型具有特殊体型外貌、抗病力强、耐粗饲、饲料转化率较高的特点。说明油麻鸡F3 A型和B型总体性状优于拜城油鸡和良凤花鸡,适合在新疆和田等地区推广。     

中国地方黄羽肉鸡与隐性白羽肉鸡二元杂交效果分析

本试验设计了2个地方黄羽肉鸡品种与隐性白羽肉鸡的杂交组合,测定比较了不同周龄的体重和屠体性状。实验结果表明,地方品种与隐性白羽肉鸡的杂交后代生长速度极显著高于地方品种纯繁后代;石歧杂和北京油鸡与隐性白羽肉鸡杂交后代间生长速度无显著差异,且北京油鸡比石歧杂表现更强的杂种优势;杂交及纯繁后代在屠体性状上有一定的差异。     

鸡AMPD1基因PCR-SSCP分析与相关性状的研究

5′-磷酸腺苷脱氨酶1(AMPD1)是嘌呤代谢中的一种重要酶类,它的功能是催化AMP(一磷酸腺苷)脱氨,生成肌苷酸(IMP),从而影响肉质风味。试验采用单链构象多态性(PCR-SSCP)技术,以隐性白羽肉鸡、白来航蛋鸡和两个地方品种(北京油鸡、三黄胡须鸡)纯系鸡为试验材料,对AMPD1基因进行SNPs检测和基因类型判别。卡方检验结果表明: 除三黄胡须鸡和隐性白羽肉鸡、北京油鸡和白来航鸡间差异不显著(P>0.05)外,其他各品种间差异极显著(P<0.01)。AMPD1基因多态性与北京油鸡生产和屠体性状(活重、胸肌率、肌苷酸含量等)相关分析结果表明:肌苷酸含量在三种基因型间差异显著(P<0.05)。初步推断AMPD1可能为影响鸡肉中肌苷酸生成的主效基因或与主效基因相连锁。     

太行鸡不同杂交组合生产性能比较研究

本研究通过引入灵山鸡(LL)、邵伯鸡(SS)与太行鸡(TT)分别进行正反杂交,测定亲本及其杂交组合公鸡体尺、屠宰性能及肉品质指标,比较主要性状杂种优势。结果显示,TT与SS杂交后代中TS的体尺、屠宰性能杂种优势明显,其次为ST,但TS遗传了邵伯鸡的矮脚特征,而ST没有;肌肉主要风味物质含量无显著性变化。综合分析,ST既提高了太行鸡产肉性能,又保持了地方鸡优质风味、节省育种成本,更符合市场需求。     

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.     

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