应用层次分析法研究公路边坡草种适应性

应用层次分析法，对中亚热带紫色砂岩地区护坡草种20个指标属性进行,得出其几个重要指标，按权重大小，依次是抗旱性，盖度，地上植物量，耐贫瘠性，地下植物量，抗寒性，绿期，根长。通过在新建公路边坡的种植试验，应用层次分析法，对4种豆科和19种禾本科牧草和草坪草的生态适应性和护坡效用进行综合评价。     

价格变动对目标性状经济值及育种效果的灵敏性分析

基于鲁西牛育种、生产和市场体系,通过构建与目标性状相联系的遗传变量和经济变量的利润函数,采用偏微分预算法和基因流动法分析价格与目标性状经济值,以及目标性状经济值与育种效果之间关系的稳健性和灵敏性。结果表明,目标性状的经济值和育种效果随着市场体系的变化而变化,且育种效果的变化和目标性状经济值的变化相关联。以上结果说明,当前市场价格体系下获得的目标性状经济权重随着市场价格变化应做适宜的调整。     

Defining a breeding objective for Nile tilapia that takes into account the diversity of smallholder production systems

In general, livestock and fish farming systems in developing countries tend to be highly diverse in terms of agro‐ecological conditions and market orientation. There are no studies that have investigated if and how this diversity translates to varying preferences for breeding objective traits. This is particularly important for breeding programmes that are organized on a national level (e.g. government‐supported nucleus breeding programmes). The aim of this study was to investigate whether Nile tilapia farmers with diverse production systems and economic constraints have different preferences for breeding objective traits. The second objective was to derive a consensus breeding goal, using weighted goal programming that could be used for a national breeding programme for Nile tilapia. A survey was conducted among 100 smallholder Nile tilapia farmers in Kenya to obtain preference values for traits of economic importance, by using multiple pairwise comparisons. Individual and group preference values were estimated using analytical hierarchy process. Low‐income farmers preferred harvest weight, while medium‐ and high‐income farmers preferred growth rate and survival. Grouping farmers according to market objective (fingerling production or fattening) showed that fingerling producers preferred growth rate and survival, while fattening farmers preferred harvest weight, height and thickness. Weighted goal programming was used to obtain consensus preference values, and these were used to derive desired gains for a breeding goal of a national breeding programme that takes into account the diversity of smallholder production systems.     

层次分析法在天然草地资源评价中的应用

运用层次分析法(AHP),以能够反映天然草地资源自然、经济特征的8项因素指标为依据,对新疆兵团阿吾斯奇牧场的天然草地资源进行了综合评价,从而探讨了天然草地资源评价的优化方法。     

Image analysis as a tool to facilitate selective breeding of quality traits in rainbow trout

A quantitative genetic analysis was performed to assess the suitability of automated image analysis of cutlets as a selection tool to genetically improve flesh composition and colour in large rainbow trout. Fish were reared on two diets with different lipid and protein content to assess the robustness of the image analysis method across different nutritional environments, and the strength of potential genotype-by-diet interactions. Chops were scanned and digitally analysed for colour (chroma, hue, and lightness) and for areas of lipid stripes, dorsal lipid, red muscle and white muscle. Percents of lipid and white muscle area to whole chop area were compared to percent chop lipid and protein recorded by chemical analysis. The results showed that on both diets, percent chop lipid and percent white muscle area displayed high phenotypic (≥ 0.42) and genetic correlations (≥ 0.70) with the respective chemical lipid and protein percents. Moreover, on both diets, the lipid area percents had moderate to high heritabilities (h² = 0.29–0.70) that were of the same magnitude or higher compared to the previously published estimates for chemically analysed lipid traits. These results confirm that regardless of the diet composition, true lipid and protein deposition can be genetically improved by selecting for the respective image analysis traits. Muscle lightness, hue (tint of colour) and chroma (saturation level of colour) displayed moderate to high heritabilities (h² = 0.32–0.46), and phenotypic and genetic correlations between these traits were favourable. Muscle colour can thus be effectively improved by selection. Some genetic constraints for breeding efforts were identified, in terms of lipid deposited at different locations within the body correlating only weakly. Genetic correlations between diets were strongly positive (≥ 0.85), revealing only weak re-ranking of families across the diet treatments.     

家蚕育种目标和素材的思考

我国家蚕育种对推动整个国家蚕丝业发展作出了重大贡献。回顾我国20世纪家蚕品种的演变,由饲养纯种到一代杂交种(1924年开始)已历经80年,在这过程中家蚕育种从小到大,从少到多,逐步发展壮大,积累经验,扩大品种资源,提     

虹鳟鱼挤压膨化饲料研究

本文采用挤压膨化饲料作为试验组，硬颗粒饲料，小杂鱼作为对照组，对虹鳟鱼养殖效果和饲养成本进行分析，试验结果表明，试验组各项性能指标均优于对照组，且单位增重的饲料成本下降，说明用挤压膨化饲料代替硬颗粒和小杂鱼养殖虹鳟鱼，可获得较好的经济效益。     

AHP模型对不同苜蓿价值的综合评定与应用

应用AHP法对31个苜蓿Medicago sativa品种品质性状进行综合评价,构造递阶层次结构和两两比较判断矩阵,通过层次单排序、层次总排序和一致性检验,求得准则层2个元素(饲用价值和生产价值)的排序权值各占0.5,因素层5个元素(营养成分、适口性、消化率、产草量和再生速度)的排序权值分别为0.319、0.129、0.052、0.334、0.169和11个品质性状的排序全向量。通过综合评分,求得31个苜蓿品种经济价值的综合评价序位,前5位为北疆苜蓿、牧歌401、爱菲尼特、全能和巨人201。最后通过层次分析法(AHP)与灰色关联度法对31个苜蓿品种经济价值的综合评价相比较,结果证明所得结果均具有可靠性,而AHP法更为合理准确。     

Assessment of serum protein fractions in rainbow trout using automated electrophoresis and densitometry

Background: Although rainbow trout (Oncorhynchus mykiss, Walbaum) are one of the most‐studied fish, electrophoretic techniques and classification of serum protein fractions have not been standardized, such that clinically useful values are lacking. Objective: The aim of the present study was to evaluate preliminarily the serum protein fractions of rainbow trout using automated cellulose acetate electrophoresis and densitometry. Methods: Serum samples from 25 rainbow trout (Oncorhynchus mykiss, Walbaum) were electrophoresed on cellulose acetate plates and quantified using densitometry. Results: A maximum of 6 fractions were identified and numbered, in order of decreasing mobility, as I, II, III, IV, V, and VI. In 3 of 25 (12%) samples, 6 fractions were identified; in 18 (72%) samples, 5 fractions were identified; and in 4 (16%) samples, 4 fractions were identified. Fractions I, V, and VI were always clearly identifiable, whereas fractions II and IV were frequently fused and indistinguishable from fraction III. The pattern with 5 fractions was the most probable type (χ², P<.01). The mean (±SEM) protein concentrations of the 6 fractions were I, 0.8±0.1 g/dL; II, 0.3±0.0 g/dL; III, 1.6±0.1 g/dL; IV, 0.3±0.1 g/dL; V, 0.6±0.0 g/dL; and VI, 0.2±0.0 g/dL. Based on comparison of serum and plasma electrophoretic patterns from 8 fish, fibrinogen was found in fraction V. Conclusion: Automated cellulose acetate electrophoresis and densitometry appear to be a practical method for estimation of serum protein fractions in rainbow trout.     

Improvement in feed efficiency and reduction in nutrient loading from rainbow trout farms: the role of selective breeding

Resource efficiency, the ratio of inputs to outputs, is essential for both the economic and environmental performance of any sector of food production. This study quantified the advancement in the feed conversion ratio (FCR) and reduction in nutrient loading from rainbow trout farming in Finland and the degree to which genetic improvements made by a national breeding program have contributed to this advancement. The study combined two datasets. One included annual records on farm-level performance of commercial rainbow trout farms from 1980 onwards, and the other included individuals across eight generations of the national breeding program. The data from the commercial farms showed that from 1980 onwards, the farm-level feed conversion ratio improved by 53.4%, and the specific nitrogen and phosphorus loading from the farms decreased by over 70%. Hence, to produce 1 kg of fish today, only half of the feed is needed compared to the 1980s. The first generation of the breeding program was established in 1992. The FCR was not directly selected for, and hence, the genetic improvement in the FCR is a correlated genetic change in response to the selection for growth and body composition. Since 1992, the estimated genetic improvement in the FCR has been 1.74% per generation, resulting in a cumulative genetic improvement of 11.6% in eight generations. Genetic improvement in the FCR is estimated to be 32.6% of the total improvement in the FCR observed at farms, implying that genetic improvement is a significant contributor to resource efficiency. The use of genetically improved rainbow trout, instead of the base population of fish, reduces feed costs by 18.3% and total production costs by 7.8% at commercial farms (by −0.266€ per kg of ungutted fish). For phosphorus and nitrogen, it can be assumed that the use of fish material with an improved FCR also leads to 18.3% less nitrogen and phosphorus flowing into an aquatic environment. Such improvements in resource efficiency are win–wins for both industry and the environment—the same amount of seafood can be produced with significantly reduced amounts of raw materials and reduced environmental impact.     

Comparison of genetic gains per year for carcass traits among breeding programs in the Japanese Brown and the Japanese Black cattle

The breeding program for beef cattle in Japan has changed dramatically over 4 decades. Visual judging was done initially, but progeny testing in test stations began in 1968. In the 1980s, the genetic evaluation program using field records, so-called on-farm progeny testing, was first adopted in Oita, Hyogo, and Kumamoto prefectures. In this study, genetic trends for carcass traits in these 3 Wagyu populations were estimated, and genetic gains per year were compared among the 3 different beef cattle breeding programs. The field carcass records used were collected between 1988 and 2003. The traits analyzed were carcass weight, LM area, rib thickness, s.c. fat thickness, and beef marbling standard number. The average breeding values of reproducing dams born the same year were used to estimate the genetic trends for the carcass traits. For comparison of the 3 breeding programs, birth years of the dams were divided into 3 periods reflecting each program. Positive genetic trends for beef marbling standard number were clearly shown in all populations. The genetic gains per year for all carcass traits were significantly enhanced by adopting the on-farm progeny testing program. These results indicate that the on-farm progeny testing program with BLUP is a very powerful approach for genetic improvement of carcass traits in Japanese Wagyu beef cattle.     

Requirement for dietary lysine and arginine by fry of rainbow trout

Triplicate lots of fry of rainbow trout (Salmo gairdneri) were fed a basal diet (47% protein) containing 67% corn gluten meal with and without a mixture of essential amino acids. The composition of the mixture was based on the differences between the amino acid contents of corn gluten meal and trout eggs. Fry fed the basal diet without added essential amino acids gained little weight, suffered high mortality and had eroded caudal fins. Addition of the mixture of amino acids (lysine, arginine, histidine, isoleucine, threonine, valine and tryptophan) significantly improved weight gain and prevented nearly all mortality and fin erosion. Single deletions of the amino acids valine, tryptophan, threonine, histidine and isoleucine had no significant effect on weight gain but the deletion of lysine alone significantly reduced weight gain and caused fin erosion and mortality. Deletion of arginine reduced weight gain (P less than .05), but did not cause mortality or fin erosion. Feeding graded levels of each of these two amino acids showed that the minimum lysine requirement for maximum growth was about 6.1% of protein, and the minimum arginine requirement was between 5.4 and 5.9% of protein. The lysine requirements for prevention of fin erosion and mortality appeared to be lower than that for maximum weight gain.     

Feed efficiency of rainbow trout can be improved through selection: different genetic potential on alternative diets

To assess the genetic potential for selection of increased feed efficiency in rainbow trout (Oncorhynchus mykiss), we estimated the heritabilities and correlations for BW, daily weight gain (DG), and daily feed intake (DFI). Body weight was recorded 5 times, and DG and DFI 3 times during a feeding trial lasting 22 mo. To test the hypothesis that phenotypic and genetic parameters were influenced by a nutritional environment, fish were fed either a modern normal protein diet (NP, 40 to 45% protein and 30 to 33% lipid) or an alternative high protein diet (HP, 50 to 56% protein, 20 to 24% lipid) in a split-family design. Results showed that there were no large differences in heritabilities between the diets. Average heritability for DFI over both diets and different fish ages was low (average h2 = 0.10), indicating that modest genetic changes in response to selection can be obtained. Average heritabilities for BW and DG over both diets and different fish ages were 0.28 and 0.33, respectively. The NP diet enabled fish to express a wide range of BW, as shown by the increased coefficients of phenotypic variation for BW. Fish fed the HP diet showed increased phenotypic variation for DFI in > 750-g fish. On the NP diet, genetic correlations of DFI with DG and BW were very strong for 750- to 2,000-g fish. In contrast, on the HP diet, the respective correlations were moderate to low, revealing more genetic potential to change growth and feed intake simultaneously in opposite directions. An analysis of the predicted selection responses showed that selection solely for high DG improved feed efficiency as a correlated genetic response. Simultaneous selection for high DG and reduced DFI, in turn, may increase genetic gain in feed efficiency by a factor of 1.2 compared with selection solely for DG. However, variation for growth and feed intake and the relationships between these traits were different in different nutritional environments, leading to divergent genetic responses on the alternative diets.     

Direct and indirect selection of visceral lipid weight, fillet weight, and fillet percentage in a rainbow trout breeding program

We assessed whether visceral lipid weight, fillet weight, and percentage fillet from BW, 3 traits laborious to record, could be genetically improved by indirect selection on more easily measured traits in farmed rainbow trout. Visceral lipid is discarded as waste during slaughter, influencing production efficiency and production costs. Fillet weight and fillet percentage directly influence economic returns in trout production. The study comprised 3 steps. First, we assessed the degree to which selection on percentage of visceral weight from BW indirectly changes visceral lipid weight and the size of intestines and internal organs. The phenotypic analysis of weights of viscera, intestines, visceral lipid, liver, and gonads measured from 40 fish revealed that phenotypic selection against visceral weight was most strongly directed to visceral lipid, and to a lesser degree to intestines and gonads. Because genetic relationships among these traits were not established, it is not known whether indirect selection leads to genetic responses. Second, we examined whether direct selection for the fillet traits could be replaced by indirect selection on BW, eviscerated BW, visceral weight, visceral percentage, head volume, and relative head volume (head volume relative to BW). The selection index calculations based on the quantitative genetic parameters obtained from multigenerational pedigree data showed that genetic improvement of fillet percentage through direct selection (selection accuracy, r(TI) = 0.54) was equally efficient compared with indirect selection on visceral percentage ( r(TI) = 0.54). Genetic improvement of fillet weight through direct selection (r(TI) = 0.56) was always more efficient than indirect selection, yet indirect selection for eviscerated BW ( r(TI) = 0.50) was almost as efficient as direct selection. Third, the expected genetic responses to alternative selection indices showed that improved fillet percentage was mainly a result of a moderate decrease in visceral weight rather than of a major increase in absolute fillet weight. Moreover, fillet percentage is challenging to improve, even if it exhibits moderate heritability (h(2) = 0.29). This is because fillet percentage displays low phenotypic variation. In conclusion, fillet weight and fillet percentage can be increased by indirect selection against visceral percentage and for high eviscerated BW.     

评估育种值对遗传进展的重要性

正生猪生产与世界的变化保持一样的快速发展。发明于法国的批次管理系统,不是生猪生产变革的唯一变化。最近,法国公司已经开始在市场上出售无抗生素的鲜猪肉。这意味着,上游的生产条件必须极佳,以便能够从断奶到屠宰都不使用抗生素,同时能保持较高的生产水平。生产链中的所有环节正从这一改进中获胜。法国由于其猪种拥有出色的遗传潜力并伴有较高的生猪生产卫生水平实现了高生产性能而闻名于世界。未来几年的问题必须现在就做好准备。猪遗传     

用层次分析法探讨海南州“十一五”草产业的发展

利用稳定现有人工草地播种面积、增加农用物质投入、改善农业生产条件、调动农牧民种草积极性、提高农业科学技术水平5个方面的21项指标,建立了海南州草地资源开发利用综合效益的评价体系。在此基础上,对海南州饲草资源开发利用状况及草产业发展采取的措施状况进行了合理的评判。结果表明,措施权重依次为发布草产品购销信息〉增加农业科研与推广投资〉增加牧草良种培育繁殖投入〉宣传推广现有的科学种草技术〉控制现有人工草地播种面积〉增加化肥有机肥投入。     

Genomic selection in multi‐environment plant breeding trials using a factor analytic linear mixed model

Genomic selection (GS) is a statistical and breeding methodology designed to improve genetic gain. It has proven to be successful in animal breeding; however, key points of difference have not been fully considered in the transfer of GS from animal to plant breeding. In plant breeding, individuals (varieties) are typically evaluated across a number of locations in multiple years (environments) in formally designed comparative experiments, called multi‐environment trials (METs). The design structure of individual trials can be complex and needs to be modelled appropriately. Another key feature of MET data sets is the presence of variety by environment interaction (VEI), that is the differential response of varieties to a change in environment. In this paper, a single‐step factor analytic linear mixed model is developed for plant breeding MET data sets that incorporates molecular marker data, appropriately accommodates non‐genetic sources of variation within trials and models VEI. A recently developed set of selection tools, which are natural derivatives of factor analytic models, are used to facilitate GS for a motivating data set from an Australian plant breeding company. The power and versatility of these tools is demonstrated for the variety by environment and marker by environment effects.     

浅谈种鸡合理用药

由于种鸡对环境条件的变化敏感、抗病能力差,加上疾病的日趋复杂化,考虑用药的预防与诊治是否合理显得越来越重要,要做到用药合理,必须掌握以下方法: 1 对鸡群用药要有预见性     

虹鳟鱼饲料中肉骨粉替代鱼粉的研究

研究在饲料中用10%肉骨粉替代10%鱼粉对虹鳟鱼的影响。试验分2个处理组,处理1组和处理2组饲料中鱼粉和肉骨粉的添加量分别为15%、10%和5%、20%,试验共进行11周。试验结果表明,2个处理组虹鳟鱼成活率、增重率、特定生长率、肥满度和饵料系数未产生显著的差异(P>0.05);处理2组单位鱼成本下降0.68元/kg,显著提高了体脂肪含量、肝体比、脏体比(P<0.05),粗灰分含量显著下降(P<0.05),体水分和体蛋白含量也表现出下降的趋势。可见,用10%肉骨粉替代10%鱼粉对虹鳟鱼的生产性能没有影响,但可影响体脂肪含量。