畜禽良种繁育技术及其应用的经济学思考

畜禽良种在畜牧产业发展中发挥核心作用,是区域畜牧业发展的物质基础,也是各国畜牧业科技竞争的焦点。现代畜禽良种繁育技术是由一系列技术组成的技术群,在畜牧业生产中的应用有助于提升优质种畜禽使用效率,加快区域畜禽养殖的良种化进程,提高畜禽生产性能。介绍了主要畜禽良种繁育技术及在我国的应用现状,分析了现代畜禽良种繁育技术对畜禽群体饲草料转化效率及良种选育效率的影响,从经济学视角探讨了现代畜禽良种繁育技术与养殖场投入及产出的关系,以期为我国建立现代畜禽良种繁育体系提供参考。     

益生凝结芽孢杆菌在肉禽养殖中的应用及作用机理研究进展

凝结芽孢杆菌(Bacillus coagulans)作为一种新型饲用益生菌,能够促进肠道健康和营养吸收、增强机体免疫力和维持肠道菌群平衡,从而提高动物生产性能。肉禽养殖是我国畜牧业重要的组成部分,如何促进肉禽养殖业的健康可持续发展、提高生产效益和无抗绿色养殖已成为当下研究的热点之一。本文就凝结芽孢杆菌的生物学特性、益生作用机理及其在肉禽生产中的应用以及目前存在的问题做一综述,为进一步开发凝结芽孢杆菌在肉禽养殖中的应用提供参考。     

Teaching international animal agriculture

Students who major in animal science at U.S. institutions are generally exposed to a curriculum that emphasizes commercial, large-scale production of the few traditional food animals: cattle, poultry, sheep, and swine. Globally, most farmers live in lesser-developed countries under limited-resource conditions of land, feed supplies, equipment, and capital. The promotion of commercial animal production enterprises may not be appropriate for such farms because it can subject farmers to considerable economic risk. Rather, use of limited numbers of large livestock, locally adapted breeds, or smaller livestock (e.g., ducks, goats, guinea pigs, and rabbits) may be more appropriate under subsistence, integrated farming systems. In this global context, a course in international animal agriculture has been taught for 15 yr to undergraduate and graduate students. The course consists of a review of traditional and potential livestock species well suited for impoverished families on small farms and methods to implement sustainable livestock projects, including feasibility, design, implementation, monitoring, and evaluation stages. To enhance student understanding, global food issues and challenges are illustrated with case studies. A term paper is also assigned for which students choose three suitable livestock species or local breeds that would be complementary on a small crop farm (< 5 ha). Daily dietary requirements of protein and energy per family member are calculated. Itemized enterprise budgets and production tables are prepared. Early in the course, the general consensus of students was that people who are malnourished and live in poverty have low personal ambition and motivation, and that their problems should be amenable to solution by application of American technology and expertise. The course modifies such attitudes and enhances a student's critical thinking and problem-solving abilities and communication skills. Course evaluations indicated that students believed that it is important to acquire some international knowledge and understanding when seeking a job, and that certain animal science courses should contain some international content. Students gain an understanding of global animal agriculture and an appreciation of the complexity of food production and hunger issues.     

Shrinking membership in the American Society of Animal Science: does the discipline of poultry science give us some clues?

Concerns have been expressed by the American Society of Animal Science (ASAS) leadership about the declining membership in ASAS. I present the viewpoint that the history of the Poultry Science Association (PSA) membership and the elimination of poultry science departments from many land grant universities could be an indication of what the future holds for animal science. I suggest that the industrialization of poultry production has led to a decline in the demand for traditionally trained poultry scientists. Industrialization of swine production is proceeding rapidly, with other animal-based industries showing the same trend. If maintaining a large ASAS membership is indeed a priority, new opportunities must be developed. Equine and companion animal programs offer such possibilities, tapping into a high level of student interest.     

Effect of multi-enzymes in combination with a direct-fed microbial on performance and welfare parameters in broilers under commercial production settings

The objective of this study was to determine the response of broilers to the combination of multi-enzymes and direct-fed microbial (DFM) under commercial production settings. A total of 7,000 1-day-old male broilers (Ross 308) were distributed over 10 pens (700 broilers/pen). Two dietary treatments were tested using complete randomized design, including a control diet and a test diet with addition of multi-enzymes (xylanase, amylase, and protease (XAP)] and DFM (a combination of spores from 3 strains ofBacillus amyloliquefaciens). Pelleted diets were offered ad libitum in 3 phases and water was freely available. During starter and grower phases (0 to 21 d), the enzyme and DFM combination resulted in improved FE (P < 0.05). During the finisher phase, higher feed intake and BW gain (P < 0.05) were observed for the test group. Overall, there were significantly higher feed intake, BW gain, and lower water-to-feed ratio in test group compared to the control group. This was related to improved (P < 0.05) modified production efficiency factor which was calculated based on final BW, survival rate, feeding period, and mortality-weight-corrected FCR. The test group had improved litter quality and a reduced foot-pad lesion score compared to the control. In addition, there was a tendency (P < 0.1) of reducingClostridium perfringens population in cecal digesta and higher lactic acid content in the ileal digesta, when expressed on an as-is basis, in the test group. In this study, we demonstrated that using a multi-enzymes and DFM combination in the diet for broilers can result in improved FE in starter/grower phases and animal welfare parameters, and lead to improved production efficiency under commercial settings.     

复合益生菌乳膏剂的制备和对断奶仔猪生长性能的影响

益生菌已经在畜禽养殖中广泛应用于动物保健。当前益生菌制剂仍存在需低温保存且有效期短的问题。此研究开发了一种由干酪乳杆菌、屎肠球菌和约氏乳杆菌组合而成的新型复合益生菌乳膏剂,在室温下贮存56 d后仍可维持较高活菌数(>108 cfu/g)。在断奶仔猪日粮中添加该复合益生菌乳膏剂可提高断奶仔猪平均日增重和末均重(P<0.05)、降低饲料增重比,而不影响平均日采食量。研究结果表明,所制备和优化的复合益生菌乳膏剂具有良好室温保存稳定性,在断奶仔猪中使用可有效促进饲料营养吸收,从而提高生长性能。     

Feeding poultry litter to grazing Boran Zebu bulls and Ogaden sheep in Ethiopia

The objective of these studies were to investigate the digestibility of poultry litter of layers and to add poultry litter to grazing Boran Zebu bulls and Ogaden sheep in East Ethiopia. Two feeding experiments (132 and 102 days) with Boran Zebu bulls (10 and 16 bulls per trial) and one feeding experiment with female Ogaden sheep (30 ewes) were carried out. All animals were grazing all day long. During the night the animals of all trials were divided into two groups each. The animals of one group of each experiment obtained poultry litter ad libitum without any other feedstuffs. Apart from feeding trials digestion experiments were carried out in order to determine the digestibility of poultry litter in 4 Ogaden sheep. The apparent digestibility of organic matter and crude protein of poultry litter amounted to 69.8 and 82.8%, the net energy content was indicated with 474 EFUc per kg of dry matter. The daily weight gain of Boran Zebu bulls fed on poultry litter was by 40 and 91 g (6.5 and 13.6% in exp. 1 and 2) higher than that of control groups. Especially during the dry season (Feb./March 1982) bulls supplemented with poultry litter were highly superior in daily weight gain (84 and 310 g per day more in exp. 1 and 2) to unsupplemented groups. The daily weight gain of Ogaden sheep fed on poultry litter in a short-term experiment (56 days) under improved grazing conditions (April-June 1982) was by 13 g per day higher than that of control animals (weight gain: 18 and 31 g per animal and day).(ABSTRACT TRUNCATED AT 250 WORDS)     

畜禽场微生物除臭技术的研究进展

畜禽场排放的氨气、硫化氢、挥发性有机物等恶臭污染严重危害人畜健康和周边环境,恶臭污染问题亟待解决。目前,畜禽场除臭方法多样,包括物理法、化学法和生物法。本文论述了微生物除臭技术的原理及在畜禽场以微生物添加剂的形式用于源头除臭、以生物过滤和喷洒的形式用于过程除臭、以发酵液等形式用于末端除臭的应用和研究进展,对微生物除臭技术现状和发展趋势进行简要分析。     

Inclusion of Buckwheat in Organic Broiler Diets

Many smaller farms in the United States are switching to organic crop production to remain competitive in an era of industrial agriculture. In doing so, they are cultivating crops not traditionally grown in the area. In the US Midwest, a popular organic crop is buckwheat. As organic corn continues to increase in price, many organic poultry farms are using alternative grains in their poultry diets, including buckwheat. Although buckwheat has been used as a livestock and poultry feed for many years, there are very few published data available on its use. The purpose of this study was to evaluate the use of buckwheat as the main ingredient in organic broiler diets. Four experimental diets were used, with varying levels of buckwheat: 0, 20, 40, and 60%. The results indicated that up to 60% buckwheat can be included in broiler diets with no significant effect on BW gain. With the 60% inclusion level, however, there was a significant decline in feed efficiency. As the price of organic corn continues to increase, the lower price for buckwheat may make it an economical substitute in organic broiler diets.     

丁酸梭菌在家禽生产中应用的研究进展

丁酸梭菌作为一种益生菌,存在于人和动物的肠道中,不易受到胃酸、消化酶和胆汁酸等因素的影响,不仅可以通过把营养物质降解成丁酸为动物提供营养与能量,而且可以保护肠道健康,促进营养物质的吸收和动物的生长,以及增强免疫功能等,因此丁酸梭菌可以作为饲料添加剂用于畜禽生产。本文对丁酸梭菌对家禽生理、生产性能的影响及其机制进行综述,以便为丁酸梭菌在家禽生产中的应用提供参考。     

乳酸菌在畜禽替抗养殖中的研究进展

随着饲料禁抗令的实施,开发利用更安全、更高效的生态制剂已经成当下畜禽养殖工作迫在眉睫的需求。乳酸菌是极具潜力的新型抗生素替代剂,通过对乳酸菌的分类、功能进行了阐述,结合乳酸菌当前在畜禽生产中已报道的益生功能机制对其替抗潜力及应用方向进行了分析、论述,以期为广大养殖工作者提供有利参考。     

微生态制剂在畜牧业生产中的应用研究展望

微生态制剂作为一种安全、绿色的新型饲料添加剂,已被广泛应用于畜牧业生产。综述了微生态制剂在畜禽养殖业中的应用研究进展,阐述了副拟杆菌作为下一代新型益生菌添加剂产品在畜牧业中的应用潜力,以期为研发新型畜禽用微生态制剂提供新思路。     

Phenolic compounds as natural feed additives in poultry and swine diets: a review

Due to ban on using antibiotics in feed industry, awareness of using natural feed additives have led to a great demand. The interest of plants phenolic compounds as a potential natural antioxidant source has been considered in research community due to their predictable potential role as feed additives in poultry and swine production.However, the mode of action for their functional role and dosage recommendation in animal diets are still remain indistinct. Taking into account, the present review study highlights an outline about the mode of action of phenolic compound and their experimental uses in poultry and swine focusing on the growth performance, antioxidant function, immune function, antimicrobial role and overall health status, justified with the past findings till to date.Finally, the present review study concluded that supplementation of phenolic compounds as natural feed additives may have a role on the antioxidant, immunity, antimicrobial and overall production performance in poultry and swine.     

临夏州现代畜牧业发展及促进新农村建设探析

新农村建设的核心在于建设现代农业。当前,临夏州正处于农业生产结构优化、农业提质增效的关键时期,建设社会主义新农村的任务十分艰巨。促进临夏现代农业农村经济又好又快发展,走具有地方特色现代农业,临夏州应把促进现代畜牧业发展摆在更加重要的位置,认真研究解决好如何加快畜牧业科技进步,转变畜牧业饲养方式,健全完善畜禽良种繁育体系,建立饲草饲料生产体系,培育和扶持市场竞争主体,建立有效的防疫体系,是发展现代畜牧业循环经济,促进新农村建设,助推脱贫攻坚的全局性突出问题。     

硒代蛋氨酸的生物学功能及其在猪生产中的应用

硒（Se）是机体必需的微量元素，其生理作用主要表现在抗氧化、免疫和抗肿瘤等方面。机体缺硒会引发骨骼肌变性或坏死、肝坏死和心肌纤维变性等疾病，因此，硒在人和动物营养方面越来越被人们重视。硒代蛋氨酸（Se-Met）作为有机硒的一种，比亚硒酸钠等无机硒具有更高的生物利用率和更低的毒性，是替代无机硒的有效有机硒源。应现阶段动物生产中对硒的需要，作者以Se-Met为研究对象，介绍了Se-Met在动物机体中的吸收代谢机制，并在此基础上与无机硒进行了比较分析，突出了Se-Met作为有机补硒剂的优越性；简述了Se-Met在机体抗氧化、免疫和抗肿瘤方面的功能、作用机制以及在猪生产中的应用效果；并进一步阐释了Se-Met在猪生产中的应用现状，通过对日增重、日采食量和料重比等生长指标，以及猪肉的pH、滴水损失、硒沉积量和肉色等肉品质指标的分析，进一步确定了Se-Met在猪生产中广泛应用的可能性，为今后猪营养中Se-Met等有机硒广泛替代无机硒提供了参考依据和理论基础，并期望为后续研究提供参考。     

The Biological Function of Selenomethionine and Its Application in Pigs Production

As an essential nutrient,selenium plays important role in antioxidation,immunity and antitumor.Selenium deficiency in the body can cause diseases such as skeletal muscle degeneration or necrosis,liver necrosis and myocardial fibrosis.Therefore,it has been paid more and more attention in human and animal nutrition.As a kind of organic selenium,selenomethionine (Se-Met) has higher bioavailability and lower toxicity than sodium selenite,and it is an effective organic selenium source to replace inorganic selenium.In response to the current demand for selenium sources in animal production,this article takes Se-Met as the research object,introduces the absorption and metabolism mechanism of Se-Met in the body,and on this basis,makes a comparative analysis with inorganic selenium,highlighting the advantages of Se-Met as an organic selenium supplement.The function and mechanism of Se-Met in the body's antioxidation,immunity and antitumor,and the effect of its application in animal production are briefly described.The application status of Se-Met in pig production is explained,and through the analysis of growth indicators such as daily weight gain,daily feed intake,and feed-to-weight ratio,as well as meat quality indicators such as pH,drip loss,selenium deposition,and meat color of pork,the possibility of Se-Met being widely used in animal production is further determined.This article aims to provide practical reference and theoretical basis for the widespread replacement of inorganic selenium by organic selenium such as Se-Met in animal nutrition in the future,and provide references for subsequent scientific research.     

Evaluation of alternatives to antibiotics using an Escherichia coli K88+ model of piglet diarrhea: effects on gut microbial ecology

Enterotoxigenic Escherichia coli is a major problem in the swine industry and results in scouring, increased mortality, and poor performance in the period immediately postweaning. The traditional way to control this problem is to include subtherapeutic antibiotics in the feed, but this is no longer acceptable to consumers; thus, alternatives to antibiotics are needed. One of the supplements that has been effective in reducing scouring in the absence of antibiotics is animal blood products produced from the rendering process. This is also becoming a problem because of concerns regarding the transfer of transmissible spongiform encephalopathies to humans from animals. In this research, we investigated the effects of spray-dried porcine plasma (SDPP), a Bacillus subtilis direct-fed microbial (DFM), a blend of organic acids, and sweeteners on E. coli-induced scouring. A total of 108 pigs of approximately 17 d of age were assigned to 6 treatments, with 3 pigs per pen, in 2 blocks, with each block having 3 replicates. The 2 blocks were initiated approximately 2 mo apart, because a sufficient number of pigs were not available that met our inclusion criteria in the first block. Diet 1 was a negative control containing no antibiotics (NC). Diet 2 was the positive control and included the same ingredient composition as NC except that antibiotics (110 mg/kg of chlortetracycline, 110 mg/kg of sulfamethazine, and 55 mg/kg of penicillin) were added (PC). Diet 3 was equal to the NC, but with a B. subtilis probiotic (DFM). Diet 4 was the NC to which SDPP was added. Diet 5 was the NC plus a combination of SDPP and DFM (SDPP + DFM). Diet 6 was the NC plus a combination of supplements, including SDPP and a blend of organic acids, DFM, and a sweetener (Blend). At 24 d of age, the pigs were experimentally infected with 6.3 x 10(9) cfu/mL of E. coli K88. All pigs were euthanized 7 d after infection and tissues were obtained for analysis. There were no significant differences among treatments for ADG, ADFI, G:F, plasma urea nitrogen, alpha-acid glycoprotein, tumor necrosis factor-alpha, intestinal ammonia, pH, or VFA. However, the PC and DFM treatments showed decreased (P < 0.05) scours at 24 h postinfection compared with the NC, SDPP, and SDPP + DFM diets. Mortality in the NC treatment, which did not contain antibiotics, was greater (P < 0.05) than in the other treatments. Terminal restriction fragment length polymorphism analysis of the 16S rDNA genes of digesta showed a greater incidence (P < 0.05) of Bacteroidetes in the PC and DFM diets than in the NC diet. When SDPP and DFM were included in the diet, the incidence of Bacteroidetes was also greater than in the NC diet (P < 0.05).     

ASAS Centennial Paper: Developments and future outlook for preharvest food safety

The last century of food animal agriculture is a remarkable triumph of scientific research. Knowledge derived through research has resulted in the development and use of new technologies that have increased the efficiency of food production and created a huge animal production and food manufacturing industry capable of feeding the US population while also providing significant quantities of high-quality food for export to other countries. Although the US food supply is among the safest in the world, the US Center for Disease Prevention and Control estimates that 76 million people get sick, more than 300,000 are hospitalized, and 5,000 die each year from foodborne illness. Consequently, preventing foodborne illness and death remains a major public health concern. Challenges to providing a safe, abundant, and nutritious food supply are complex because all aspects of food production, from farm to fork, must be considered. Given the national and international demand and expectations for food safety as well as the formidable challenges of producing and maintaining a safe food supply, food safety research and educational programs have taken on a new urgency. Remarkable progress has been made during the last century. Wisdom from a century of animal agriculture research now includes the realization that on-farm pathogens are intricately associated with animal health and well-being, the production of high-quality food, and profitability. In this review, some of the developments that have occurred over the last few decades are summarized, including types, sources, and concentrations of disease-causing pathogens encountered in food-producing animal environments and their association with food safety; current and future methods to control or reduce foodborne pathogens on the farm; and present and future preharvest food safety research directions. Future scientific breakthroughs will no doubt have a profound impact on animal agriculture and the production of high-quality food, but we will also be faced with moral, ethical, and societal dilemmas that must be reconciled. A strong, science-based approach that addresses all the complex issues involved in continuing to improve food safety and public health is necessary to prevent foodborne illnesses. Not only must research be conducted to solve complex food safety issues, but results of that research must also be communicated effectively to producers and consumers.     

Formulation challenges of organic poultry diets with readily available ingredients and limited synthetic methionine

Organic agriculture has increased greatly over the past several years as consumer demand for these products has risen. Organic meat production, including poultry, has grown especially quickly, resulting in increasingly stringent guidelines being put in place to ensure safe, uniform, and ideal products for these consumers. Feed formulation and manufacturing for organic poultry in the United States are strictly regulated by the United States Department of Agriculture National Organic Program. Currently, no synthetic amino acids are allowed to be used in organic poultry diets in the United States except for limited quantities of synthetic methionine since it is typically considered the first or second limiting amino acid in corn and soybean meal based poultry diets and it is a critical nutrient for maintaining bird growth and productive performance, especially regarding egg size in laying hens. The aim of the review herein is to discuss the impacts that current organic regulations on synthetic methionine have on diet formulation when using readily available ingredients. High levels of crude protein must be used to meet bird methionine requirements with this restriction in place, which both increases feed costs and can have negative impacts on bird health and on air quality and the surrounding environment due to increased ammonia emissions. Atypical feed formulation strategies have been explored to address this issue, including such methods as feeding alternative ingredients and providing forage materials. Another possibility would be to use an average lifetime maximum inclusion rate for synthetic methionine, which may allow for better flexibility to provide sufficient methionine throughout various phases of growth and production since the requirements of the bird change with age.     

The effect of a direct-fed microbial (Primalac) on turkey live performance

Two pen trials and 2 field trials were conducted to determine whether a direct-fed microbial (DFM; Primalac) was effective in improving turkey productive performance. In the pen trials, typical turkey diets were formulated with and without Primalac. All feed was provided by a commercial feed mill. In trial 1, Large White male turkey poults were placed in 48 pens (18 birds/pen, 24 pens/treatment) on the day of hatch and were reared to 20 wk. In trial 2, Large White female turkey poults were placed in 48 pens (30 birds/pen, 24 pens/treatment) on the day of hatch and were reared to 18 wk. Cumulative FCR was significantly improved for birds fed DFM feed compared with birds fed control feed at 20 wk in trial 1 and at 8 wk in trial 2. Body weight was significantly greater for birds fed DFM feed compared with birds fed the control feed through 12 wk in both trials. In 2 field trials, 2 brooder houses and 4 grow-out houses were paired on each farm (4 brooder houses and 8 grow-out houses total). All birds received the same feed provided by the integrator. The DFM was provided in the water from placement to market in 1 brooder house and in the 2 matching grow-out houses. Breeder flocks were equally represented in both brooder houses within each trial. Approximately 12,000 male poults were placed in each brooder house and were transferred to 2 grow-out houses at 5 wk. Although no statistical analyses were computed for the field trials, there was a nominal improvement in performance associated with the DFM: mean livability was increased by 3.5%, mean BW was increased by 0.9 kg (2 lb), mean total weight removed from the farms was increased by 13,706 kg (30,153 lb), mean FCR was improved by 0.165, and cost of production was reduced by $0.0195/kg ($0.043/lb) of BW by the DFM. In conclusion, the DFM product (Primalac) used in these studies was effective in improving turkey live performance.