不同杂交组合羔羊生长性能比较试验报告

选择3月龄左右的无角陶赛特与小尾寒羊杂交F1羔羊30只,特陶寒F2羔羊30只,以相同月龄的小尾寒羊30只为对照,研究舍饲条件下,陶寒和特陶寒、小尾寒羊生长发育、生产性能的比较试验短期育肥的效果。结果表明,育肥末期特陶寒平均日增重显著高于陶寒羊(P0.05);特陶寒在体长、胸围和管围上均显著高于陶寒羊(P0.05);从经济效益来看,特陶寒组与陶寒组相比,每只羔羊可多赢利28.8元。     

不同杂交组合肉兔繁殖性能及生长性能的对比研究

引进国内外5个优良肉兔品种,选择8个不同的杂交组合,对比研究不同杂交组合肉兔的窝均产仔数、40日断奶成活数、40日断奶成活率、初生窝重(平均个体重)、40d断奶窝重(平均个体重)、90d个体重等技术经济指标,筛选出适合攀枝花肉兔发展的优良肉兔杂交组合2～3个,以指导攀枝花肉兔的生产实际。对比研究结果表明:适合攀枝花肉兔发展的优良肉兔杂交组合为比利时♂×加利福尼亚♀,新西兰♂×加利福尼亚♀,比利时♂×新西南♀。     

不同杂交组合猪肥育性能与肉品质的研究

试验选用二元大长(Y×L)、三元杜长大(D×LY)、杜大长(D×YL)、三元皮大长(P×YL)4个杂交组合作为试验动物,进行生长发育性能、胴体品质性状测定,旨在为优质肉高效配套杂交组合筛选提供理论依据。研究表明:D×LY、D×YL日增重、料重肉比及屠宰率最优,日增重、屠宰率与L×Y差异显著(P<0.05),D×YL屠宰率、眼肌面积分别为76.2%、47.62cm2,为4组合中最高,并与Y×L差异显著(P<0.05),与D×LY、P×YL组差异不显著(P>0.05)。     

不同杂交组合母羊繁殖性能的观察

随机选择波本、萨本、波萨本母羊各300只用波尔山羊公羊配种,观察其受胎率、妊娠期、产羔率等指标,以期了解各杂交组合母羊的繁殖性能,结果表明:这3个杂交系母羊在情期受胎率、妊娠期和产羔率上无显著差异(P<0.05雪,萨本母羊难产率高而波本母羊后代2月龄成活率较低,说明在生产实践中,推行波萨本杂交模式最为理想。     

不同杂交组合牛在繁殖间的性能研究

在对当地黄牛采取人工杂交改良过程中,本文根据不同品种公牛的冻精将母牛群分组,并统计各组母牛的受胎率、牛犊的难产率、繁殖成活率和出生时的体尺、体重.统计结果表明各组间母牛的受胎率均无明显差异(p＞0.05);牛犊的繁殖成活率也具是相同的结果.但各组杂种牛犊的难产率均高于土种黄牛的值,并且F1(西门塔尔×黄牛)和F1(荷斯坦×黄牛)的值与对照组差异显著(P＜0.05),F1(皮埃蒙特牛×黄牛)的值与对照组差异不显著(p＞0.05).牛犊额头宽度与牛犊的难产率之间呈正相关(r=0.8304)     

不同杂交组合尖塘鳢形态性状和生产性能的比较研究

本试验由云斑尖塘鳢、线纹尖塘鳢的自交、杂交及其回交试验组合及其子一代在同一环境条件下进行持续360d养殖试验,通过测量各组试验鱼的形态性状和生产性能,并进行比较分析。试验结果表明,无论正反杂交还是回交,其子代在形态性状和生产性能方面均出现较大变化,通过杂交子一代与云斑尖塘鳢亲本进行回交所得到的回交杂种在体色上得到改良,成活率、生长速率、起捕率、饵料转化率等各项生产性能也得到较好的巩固。     

不同杂交组合牛在繁殖期间的性能研究

在对当地黄牛采取人工杂交改良过程中,本文根据不同品种公牛的冻精将母牛群分组,并统计各组母牛的受胎率、牛犊的难产率、繁殖成活率和出生时的体尺、体重。统计结果表明:各组间母牛的受胎率均无明显差异(p>0.05);牛犊的繁殖成活率也具是相同的结果。但各组杂种牛犊的难产率均高于土种黄牛的值,并且F1(西门塔尔×黄牛)和F1(荷斯坦×黄牛)的值与对照组差异显著(P<0.05),F1(皮埃蒙特牛×黄牛)的值与对照组差异不显著(p>0.05)。牛犊额头宽度与牛犊的难产率之间呈正相关(r=0.8304)     

肉兔生产与小环境的关系

近年来，肉兔价格一直持续在高价位。商品肉兔价格平均在11元/kg以上，因此。投资养殖肉兔的单位、业主、专业户不断增加。但肉兔养殖又是一个环节多。工作细的养殖业。笔者认为，养殖肉兔。首先必须了解和熟悉肉兔生产与小环境的关系。     

不同群体山女鳟及其杂交F1的生产性能比较

本文系统研究了我国引进的两个山女鳟（Oncorhynchusmasoumazou）群体及其杂交F1代的生产性能。结果表明,（1）两个杂交组合的早期生产性能,如授精率、发眼率和孵化率等不存在显著优势,自交组合BH08♀×BH08♂的最终成活率为63．37％,远低于其他三组的成活率（P〈0．01）;（2）378d的生长对比试验表明,杂交组合与自交组合的体质量、绝对增重率、特定生长率和肥满度等存在一定差异,养殖时间对这些指标的影响达到极显著水平（P〈0．01）,但组间差异仅为显著水平（P〈0．05）或没有差异（P〉0．05）;（3）378d的生长对比试验结束时,两个杂交组合均表现出一定的杂种优势。方差分析表明,不同生长阶段对杂交组合杂种优势率的影响极显著（P〈0．01）,不同组合间的杂种优势率也存在极显著差异（P〈0．01）。     

不同杂交组合育肥猪经济效益对比试验

为了探索育肥猪的最好经济效益和社会效益,2005年5月11日至9月10日,笔者进行了本地猪、二元杂交猪、三元杂交猪不同组合育肥猪的对比试验,试验结果表明:二元杂交和三元杂交猪头平均日增重分别比本地猪增加102g、168g;头平均纯收入分别增加95.56元、157.60元。三元杂交猪均优于二元杂交猪和本地猪。     

獭兔睾丸组织形态观察

獭兔是一种典型的经济动物,它既是毛皮动物又可食用,普遍应用于人类生产生活。目前已有研究报道了多种哺乳动物生精周期研究,但很少有关于獭兔的报道。本实验对2只完全性成熟的健康獭兔进行睾丸结构,生精周期相对频率,支持细胞效率研究。獭兔睾丸经石蜡包埋,HE染色以便进行组织形态学观察。不同的生殖细胞组合分析显示30%的曲精小管显示两个或两个以上的生精上皮周期阶段。獭兔生精周期阶段频率(%)分别为:阶段1:(15.5±2);阶段2:(14.0±1);阶段3:(11.5±1);阶段4:(8.5±1);阶段5:(10.5±1);阶段6:(18.5±2);阶段7:(13.0±1);阶段8:(8.5±1)。支持细胞效率(圆形精子:支持细胞=7:1)。本研究结果表明獭兔的生精效率较其他哺乳动物高。     

奇可利和紫花苜蓿对新西兰白兔生产性能影响的研究

选取35日龄和45日龄的断奶新西兰白兔各24只,分别随机分为3组,每组8只。对照组只喂精料,试验I组用紫花苜蓿代替20%基础日粮,试验II组用奇可利代替20%基础日粮,比较这3组试验兔的增重、日增重、生长速度、料重比,分析比较2种牧草的经济效益。结果显示:试验期内试验I组日增重分别为36.88、37.18g,试验II组日增重分别为35.40、35.65g,对照组日增重分别为33.63、34.39g,试验I组、试验II组和对照组肉兔的只均增重和日增重均存在极显著差异(P<0.01);但试验I组的料重比分别比对照组下降4.60%、4.68%,试验II组的料重比分别比对照组下降9.51%、9.06%;试验II组比试验I组和对照组的只均获利高,经济效益好。由此可见,用奇可利和紫花苜蓿代替部分精饲料是可行的。     

日粮中添加酶制剂对肉兔生长性能的影响

为研究日粮中添加饲用酶制剂对新西兰肉兔生长性能的影响,特进行本试验。选择60只30日龄断奶新西兰兔按窝配对分为3组,C组为对照组,T1组和T2组日粮中分别添加0.8%和0.15%饲用复合酶制剂,测定各组日增重、日耗料、饲料转化率。结果表明:肉兔日粮中加入适量的酶制剂可以提高肉兔的日增重和饲料转化率,降低生产成本;酶制剂的剂量以0.15%效果较好,0.8%的酶制剂剂量似有些过量。     

Comparative performance of fixed-film biological filters: Application of reactor theory

Nitrification is classified as a two-step consecutive reaction where R₁ represents the rate of formation of the intermediate product NO₂-N and R₂ represents the rate of formation of the final product NO₃-N. The relative rates of R₁ and R₂ are influenced by reactor type characterized hydraulically as plug-flow, plug-flow with dispersion and mixed-flow. We develop substrate conversion models for fixed-film biofilters operating in the first-order kinetic regime based on application of chemical reactor theory. Reactor type, inlet conditions and the biofilm kinetic constants K_i (h⁻¹) are used to predict changes in NH₄-N, NO₂-N, NO₃-N and BOD_5. The inhibiting effects of the latter on R₁ and R₂ were established based on the γ relation, e.g.:

where BOD_5,max is the concentration that causes nitrification to cease and N is a variable relating K_i to increasing BOD₅. Conversion models were incorporated in spreadsheet programs that provided steady-state concentrations of nitrogen and BOD₅ at several points in a recirculating aquaculture system operating with input values for fish feed rate, reactor volume, microscreen performance, make-up and recirculating flow rates. When rate constants are standardized, spreadsheet use demonstrates plug-flow reactors provide higher rates of R₁ and R₂ than mixed-flow reactors thereby reducing volume requirements for target concentrations of NH₄-N and NO₂-N. The benefit provided by the plug-flow reactor varies with hydraulic residence time t as well as the effective vessel dispersion number, D/μL. Both reactor types are capable of providing net increases in NO₂-N during treatment but the rate of decrease in the mixed-flow case falls well behind that predicted for plug-flow operation. We show the potential for a positive net change in NO₂-N increases with decreases in the dimensionless ratios K_2,(R2)/K_1,(R1) and [NO₂-N]/[NH₄-N] and when the product K_1,(R1)t provides low to moderate NH₄-N conversions. Maintaining high levels of the latter reduces the effective reactor utilization rate (%) defined here as (RN_avg/RN_max)100 where RN_avg is the mean reactive nitrogen concentration ([NH₄-N] + [NO₂-N]) within the reactor, and RN_max represents the feed concentration of the same. Low utilization rates provide a hedge against unexpected increases in substrate loading and reduce water pumping requirements but force use of elevated reactor volumes. Further γ effects on R₁ and R₂ can be reduced through use of a tanks-in-series versus a single mixed-flow reactor configuration and by improving the solids removal efficiency of microscreen treatment.     

不同投喂率和投喂频率对大杂交鲟幼鱼生长、体成分和生化指标的影响

为探讨大杂交鲟(Huso dauricus♀×Acipenser schrenckii♂)适宜投喂率和投喂频率,本实验分别设计了5个投喂率(0.4%、0.8%、1.2%、1.6%和2.0%)和5个投喂频率(1次/d、2次/d、3次/d、4次/d和5次/d),研究不同投喂率和投喂频率对大杂交鲟生长、体成分和生化指标的影响。投喂率实验中鱼初重(335.87±0.82)g,投喂频率实验中鱼初重(334.77±1.06)g,养殖周期为10周。结果表明,随着投喂率升高,实验鱼增重率、特定生长率、肝体比、脏体比、肥满度,肌肉粗蛋白、粗脂肪和肝粗脂肪含量显著升高(P0.05),血清谷丙转氨酶、谷草转氨酶和胃蛋白酶活性均显著升高(P0.05);饲料效率、全鱼和肌肉水分含量均显著降低(P0.05);全鱼粗脂肪含量,血清总蛋白、白蛋白和高密度脂蛋白胆固醇含量,肠脂肪酶活性呈先升高后降低趋势(P0.05)。随着投喂频率增加,实验鱼增重率、特定生长率和饲料效率无显著差异(P0.05);1次/d投喂频率组脏体比、肥满度和全鱼粗脂肪含量显著低于其他各组(P0.05),2次/d投喂频率组全鱼粗蛋白含量显著高于其他各组(P0.05)。不同投喂频率对实验鱼除血清葡萄糖含量以外的其他血清生化指标和胃肠消化酶活性或含量均无显著影响(P0.05)。综合以上结果认为,在300～600g大杂交鲟的养殖过程中日投喂率在1.2%～1.6%,投喂频率为2次/d比较适宜。     

不同稻田综合种养模式的成本效益分析

为获知和分析稻田综合种养模式在中国的发展现况及存在问题,根据2013年中国4个省份两种主要稻田种养模式的调查数据,采用Kruskal—Wallis非参数检验等方法分析了不同稻田种养模式在生产投入、经济效益上的差异以及在化肥、农药减量等方面的效应。结果显示,稻田综合种养具有较好的经济和生态效益,稻蟹、稻鱼两种种养模式的平均利润为水稻单作的2.43~3.92倍,化肥成本减少2.8%~49.2%,农药成本减少3.2%~83.6%,但技术成熟度及产业化程度的差异使种养户在最终经济收益及生态效益上的极差较大。研究表明,中国稻田综合种养规模化程度不够、成本投入偏高、综合种养生态、社会效益提升有限是目前面临的主要问题,因此加大政府的扶持力度,加强种养关键技术的研究,因地制宜将规模化的现代农业与传统稻田种养相结合是解决这些问题的关键。     

Effect of three different oil cake-based diets on pond production performance of silver barb, Puntius gonionotus (Bleeker)

One of the three iso-nitrogenous (30% crude protein) and iso-energetic (15.0 MJ kg⁻¹ diet) oil cake-based diets (groundnut, D-1; soybean, D-2 and mustard, D-3) was fed to the fingerlings (6.61 ± 0.06 g) of silver barb ( Puntius gonionotus ) for 120 days in triplicate fertilized ponds (0.04 ha) with a stocking density of 9000 fish ha⁻¹. Fish were fed at 10% of their body weight for the first month, followed by 3% in the second and 2.5% in the third and fourth months of the culture period. The fish fed diets D-1, D-2 and D-3 grew from initial weights of 6.67, 6.67 and 6.50 g to 320.23, 298.23 and 305.13 g respectively. No significant variation ( P >0.05) was found in the growth and nutrient utilization of fish fed different dietary treatments. Net profits of Indian Rupees 67 385, 59 535 and 65 790 ha⁻¹ were obtained in fish fed D-1, D-2 and D-3, respectively, within 120 days of culture. The results of this study suggest the possibility of the use of mustard oil cake as a dietary protein source for pond culture of silver barb in addition to groundnut and soybean oil cakes without compromising the growth, nutrient utilization, production performance and economics of culture of this fish.     

木聚糖酶对肉鸭生产性能的影响

实验选取半番鸭作为实验对象。选取1日龄的生长情况基本一致的健康半番鸭200只,随机分为5组,进行对照试验,采用单因子试验设计,在5组半番鸭的日粮中分别添加木聚糖酶50g/t、100g/t、150g/t、200g/t和0g/t,试验为期45d。结果表明:在半番鸭的日粮中添加合适的木聚糖酶剂量,满足其正常的生长发育所需要的环境条件,自由采食和自由饮水,并且搞好饲养管理,半番鸭就能够进行正常的生长发育。最后通过经济效益分析,在半番鸭的日粮中添加150g/t的木聚糖酶可明显的改善半番鸭的生产性能,从而提高饲料的利用率,降低饲养成本。     

Mass production of hybrid magur and its culture potential in Bangladesh

Fertility, survival rate and hatching rate of hybrids of local magur Clarias batrachus and African catfish C. gariepinus were compared with the purebred species. Hybridization was conducted by hormone injection of purebreds and F₁ hybrids (F₁‐A), and artificial fertilization. Pure parental crosses as well as possible hybrid combinations were obtained. The fertility of F₁ hybrids (F₁‐A), purebred C. batrachus and C. gariepinus was 71.0%, 46.5% and 84.0% respectively. The fertility of an F₂ hybrid was 32.0%. The timing of embryonic developmental stages of F₁ hybrids (F₁‐A) was similar to that of purebred species. The hatching rate and survival rate of F₁ hybrids (F₁‐A) up to first feeding stage were 33.0% and 48.3%, respectively, which were significantly higher (P > 0.05) than the purebred C. batrachus. Only three embryos of an F₂ hybrid hatched successfully, and only one of these survived. The embryonic development of F₁ hybrids (F₁‐A) and their hatchability and survivability ensured the viable capacity of their progeny for mass culture. Hybrid morphology, both external and internal, was intermediate to that of the parents.