GMOs in animal agriculture: time to consider both costs and benefits in regulatory evaluations

In 2012, genetically engineered （GE） crops were grown by 17.3 million farmers on over 170 million hectares. Over 70% of harvested GE biomass is fed to food producing animals, making them the major consumers of GE crops for the past 15 plus years. Prior to commercialization, GE crops go through an extensive regulatory evaluation. Over one hundred regulatory submissions have shown compositional equivalence, and comparable levels of safety, between GE crops and their conventional counterparts. One component of regulatory compliance is whole GE food/feed animal feeding studies. Both regulatory studies and independent peer-reviewed studies have shown that GE crops can be safely used in animal feed, and rDNA fragments have never been detected in products （e.g. milk, meat, eggs） derived from animals that consumed GE feed. Despite the fact that the scientific weight of evidence from these hundreds of studies have not revealed unique risks associated with GE feed, some groups are calling for more animal feeding studies, including long-term rodent studies and studies in target livestock species for the approval of GE crops. It is an opportune time to review the results of such studies as have been done to date to evaluate the value of the additional information obtained. Requiring long-term and target animal feeding studies would sharply increase regulatory compliance costs and prolong the regulatory process associated with the commercialization of GE crops. Such costs may impede the development of feed crops with enhanced nutritional characteristics and durability, particularly in the local varieties in small and poor developing countries. More generally it is time for regulatory evaluations to more explicitly consider both the reasonable and unique risks and benefits associated with the use of both GE plants and animals in agricultural systems, and weigh them against those associated with existing systems, and those of regulatory inaction. This would represent a shift away from a GE evaluation process that currently focuses only on risk assessment and identifying ever diminishing marginal hazards, to a regulatory approach that more objectively evaluates and communicates the likely impact of approving a new GE plant or animal on agricultural production systems.     

Direct Costs of Bovine Spongiform Encephalopathy Control Measures in Germany

On 26 November 2000, the first autochthonous case of bovine spongiform encephalopathy (BSE) was detected in Germany. Since then, a total of 413 BSE cases have been confirmed, resulting in the culling and destruction of 17 313 heads of cattle. In view of the possible risks for human and animal health, Germany has adopted EU regulations along with some additional requirements concerning active surveillance and response measures after detecting a BSE‐positive animal. In this study, we used a stochastic model to estimate the costs incurred by the ensuing legislative amendments responding to BSE between November 2000 and December 2010. The total costs were estimated to range between 1847 and 2094 million Euros. They peaked in 2001 (about 394 million Euros) and declined since. About 54% of the costs (approximately 1000 million Euros) were incurred by the extension of the feed ban for animal protein to all farmed livestock. Active surveillance accounted for 21% (405 million Euros), the incineration of animal protein for 13% (249 million Euros) and the removal of specified risk material for 11% (225 million Euros). Only 1% of the costs was related to response measures after detecting a BSE‐positive animal, including indemnity payments for culled cattle and confiscated carcasses at the slaughterhouse.     

Layers in aviary system: Effects of beak trimming and alternative feed formulation on technical results and egg quality

Although the transition from cage housing to alternative systems commenced more than 20 yr ago, there is still an ongoing need for information supporting system understanding, system development, and genetic selection. Cannibalism remains one of the largest problems in these housing systems. Furthermore, recent developments in feed prices have increased the price of animal feed, raising production costs of eggs. Replacing feedstuffs with cheaper self-grown crops might be a possible solution to lower feed costs. In Belgium, and more specifically, in the Kempen region, corn is a widely grown crop that is usually used for feeding dairy cows, yet a ground mix of dry corn grains and a small part of the cob, known as corn cob mix (CCM), can also be used as poultry feed. In this paper the effect of the fibrous feed CCM on the prevalence of cannibalism on hens with trimmed and untrimmed beaks is investigated. The results show a positive effect of CCM on mortality; nevertheless, the mortality in the groups of untrimmed hens was very high, indicating the importance of beak trimming. Furthermore, a positive effect of CCM on egg weight was observed.     

5-羟色氨调控动物采食的研究进展

关于5-羟色氨(5-HT)对采食量的影响已有几十年的研究历史。机体内的5-HT主要是以必需氨基酸色氨酸(Trp)作为前体物,在大脑和肠道中合成,并在机体中发挥重要的作用。5-HT无法直接透过血-脑屏障,因此中枢神经系统和外周5-HT作为两个相对独立的系统各自发挥作用。目前,已有大量的研究表明中枢5-HT的多种受体以不同的方式调控动物采食,主要有5-HT1A、5-HT1B、5-HT2A、5-HT2C、5-HT3A、5-HT4、5-HT5A、5-HT6和5-HT7。例如,现在临床上被批准使用的抗肥胖药物氯卡色林就是一种5-HT2C受体激动剂。此外,中枢5-HT还可以协同胰高血糖素样肽-1、饥饿素和胆囊收缩素等外周激素共同调控动物采食行为。外周5-HT也能够通过介导胰高血糖素样肽-1和胆囊收缩素来诱导饱腹感。畜禽生产中主要通过在饲料中添加Trp来增加动物体内5-HT的合成。但目前对于Trp对畜禽采食量的调控机制的研究尚不完善,且有研究表明,不同浓度的Trp对动物采食量的影响不同,不同畜禽饲料中最适Trp的浓度也不同。而Trp主要是通过其代谢产物5-HT来调控动物采食。作者查阅了大量国内外最新的研究成果,从中枢和外周两个途径对5-HT调控动物采食行为的研究进展作一综述,期望通过对Trp的代谢产物5-HT对动物采食调控机制的探讨,为Trp在畜禽生产中的应用提供一定的理论依据。     

两用（粮食和饲料）作物研究现状及发展前景

随着经济发展和收入水平的提高，居民对粮食消费量出现降低和对畜产品需求量出现增加的现象并存，但优质饲料的缺乏阻碍了畜牧业的发展。两用（粮用和饲用）作物增加了冬季饲料供应，其已成为一些国家或地区农业生产系统中的重要组成部分（主要分布于农牧交错区）。梳理近年来国内外关于两用作物生产和利用的现状及发展趋势，重点概述的内容有：1）两用作物的利用背景；2）两用作物的概念；3）代表性地区；4）饲草、籽粒产量和经济收益；5）动物利用和畜产品等。同时，对当前两用作物生产系统中面临的问题和应对举措进行了展望，包括：1）播种时间和播种量的选择；2）放牧或刈割后的氮肥管理；3）作物放牧或刈割的适宜生育期；4）种质资源的选择等。总体而言，两用作物生产管理（包括放牧时间、施氮量、播种量和放牧强度等）不当增加了籽粒产量降低的风险，但基于农业生产系统的综合效益，作物以两用的形式进行生产和利用是有利可图的。     

An Evaluation of Microbial Health Risks to Livestock Fed with Wastewater‐Irrigated Forage Crops

This paper presents the results of five experiments in which animal health risks associated with the consumption of crops irrigated with domestic wastewater were evaluated. Forage maize and Tanner grass were irrigated with treated wastewater and used in goats and calves feeding trials. The irrigated crops presented high levels of surface contamination with E. coli (10⁴–10⁷ 25 g^?1) and salmonellae (up to 1.6 × 10⁴ 25 g^?1), but none of the animals showed signs of infection or of disease. Further, the microbiological quality of animal products always complied with the Brazilian and European Union standards for food safety. It is suggested that the WHO guideline values for restricted irrigation (≤10⁴ E. coli 100 ml^?1 and ≤1 helminth egg l^?1), which were developed to protect the health of agricultural field workers, would be equally protective of the health of both animals fed with wastewater‐irrigated crops and humans consuming products from such animals.     

益生菌在反刍动物生产中应用的研究进展

益生菌可以作为一种绿色添加剂应用于反刍动物饲料中,逐渐替代抗生素、激素、农用化学物质。大量研究表明,其一有益微生物菌剂可以调节动物体肠道内正常的微生物关系,并提高动物体的代谢水平和其对营养物质的利用率;其二有益微生物菌剂能够增强机体的免疫功能,进而提高机体的免疫和抗病能力;其三有益微生物菌剂可以起到减少污染和净化环境的作用。研究主要针对有益微生物的主要功能和其作用机理,以及近年来其在反刍动物营养和饲料中的应用研究进展进行综述。     

动物饲养试验的关键环节及考核要素

动物饲养试验是动物营养与饲料科学研究的重要方法之一,常用来评价饲料的营养价值、筛选最佳饲粮配方、研究营养代谢及营养需要等,是目前多数农业院校动物营养与饲料科学课程的实践教学内容,其中涉及多个关键环节,包括考查因素、水平、试验动物、试验日粮、试验设计、考查指标、数据收集与整理、数据统计等,正确把握这些环节是动物饲养试验取得良好效果的关键,也是该课程中需要考核的要素。对动物饲养试验的多个关键环节进行了讨论和总结,供实践教学课程参考和借鉴,以期提高教学效果和推进实践教学改革。     

Proposed changes in living conditions for broilers under the National Organic Program will have limited economic effects

In the current paper, we estimate the costs and benefits of implementing the proposed rule for changes in living conditions for organic broilers. In contrast to the effects of the proposed rule for changes in living conditions for laying hens, the effects of the rule on organic broilers is anticipated to be relatively limited. All producers are already in compliance with option 2 of the rule, and changes required under option 3 are minimal for most producers. Using the per-farm estimated regulatory costs and the estimates of production volumes and actual prices, the total estimated annual industry cost under option 3 is $2.4 million, which represents 0.1% of total industry revenue. The estimated benefits associated with this type of perceived animal welfare improvement are high enough to cover the anticipated cost, and the proposed option easily passes the benefit-to-cost ratio test.     

Studies of the tolerance and toxicity of Luzern-green-meal pellets after selenium fertilization

In a feeding trial, rabbits allotted in 3 experimental groups were fed rations containing 2.09, 9.83 and 19.5 mg selenium/kg feed in the form of selenium-enriched alfalfa green meal pellets. The selenium enrichment was done by foliar application (spraying) of the 20--25 cm high plant stand with 2.5 kg SeO2 per hectare in watery solution. The control animals were given normal alfalfa green meal pellets of 0.16 ppm selenium content. Toxicity and lethality, tolerance limit and nutritive effect of the pellets were studied. Plant-assimilated selenium was found to be converted more efficiently by the animal organism than was selenium from inorganic compounds (higher retention rate, better gain in body weight and lower feed expenditure). Therefore, the selenium supply to farm animals should be improved by feeding crops that were given selenium dressings.     

酶制剂在母狐貉饲料中的应用效果

近些年因毛皮动物养殖业的发展,出现了对小鱼、小虾等幼龄水产品的过度捕捞情况,使淡水鱼类资源遭到严重破坏,饲料的价格高涨,养殖成本增加,降低了养殖户经济效益。针对此现状,本试验通过不同酶制剂的应用,以植物蛋白源和鱼粉来替代狐貉日粮中的新鲜动物饲料,最终达到减轻环境压力,降低饲养成本,提高狐貉养殖经济效益的目的。     

Microbial risks--from animal farming to the food

Microorganisms by far are representing the most important cause for food safety risks. Sources of food contamination are given along the whole food chain. The most frequent causative agents of food infections, Salmonella and Campylobacter, mostly can be found in the animals herds. A real improvement of the situation can only be reached by a strong inclusion of the agricultural area in the programs for repressing the pathogens. Problems in animal health and premortal stress of the slaughter animals cause considerable bacterial translocation processes and increase the consumer risks. Only few publications exist on the influence of the animal farming systems on the development of microbial food risks. The consumer accepts only animal management systems, which meet the demands for animal welfare, economical efficiency and especially the demand for product safety.     

Estimation of nitrogen and phosphorus flows in livestock production in Dianchi Lake basin,China

We assessed the nitrogen (N) and phosphorus (P) flows in intensified livestock production systems by investigating nutrient budgets and cycling in the basin of Dianchi Lake, one of the most eutrophic lakes in China. We conducted field surveys based on feed samplings and interviews of livestock farmers. The N and P in local and external feeds, animal body retentions, animal products and excretions were calculated at the individual level for dairy cattle, fattening pigs, breeding sows, broilers and laying hens. The N and P flows in the total livestock production system in the area were estimated by multiplying the individual N and P budgets by the number of animals. For the dairy and fattening pig productions, N and P supplied from local crops or by‐products accounted for large parts of the inputs. For the other livestock categories, most of the N and P inputs depended on external resources. The N and P outputs through animal manure into the cropland were 287 and 66 kg/ha/year, respectively, which were higher than the N and P inputs into the livestock production systems from the cropland. The N and P loads from manure should be reduced for the establishment of sustainable agricultural production systems.     

The relationship between residual feed intake and feed intake behavior in group-housed Duroc barrows

Because feed is the major input in pork production, conversion of feed into lean tissue at minimum costs has been a focus for improvement. Several researchers have proposed using residual feed intake (RFI) rather than feed conversion ratio (FCR) for genetic improvement of feed efficiency. Little is known about the variation in RFI in pigs. As several studies suggest a greater RFI is related to greater animal activity levels, the current study investigated the phenotypic relationship between RFI and feed intake (FI) behavior of 104 group-housed growing Duroc barrows allowed ad libitum access to feed. Feed intake, BW gain, feeding time (TIME), feeding frequency (VISITS), RFI, and FCR were calculated for 5 periods of 14, 23, 28, 21, or 23 d in length (periods 1 through 5, respectively) on animals that were between 73 to 95 d of age at the start of the testing period. Barrows that grew faster consumed more feed (P < 0.001), and barrows that consumed more feed were fatter (P < 0.01). There were no correlations between VISITS and TIME, between VISITS and FI, or between VISITS and RFI. Barrows that spent more time at the feeder, however, consumed more feed (P < 0.05) and had greater RFI in periods 1, 3, and 5 (P < 0.05). As expected, FI and FCR were highly correlated with RFI (P < 0.001). These results suggest that a greater FI rather than greater feed intake activity resulted in greater RFI values.     

Examination of mink (Mustela vison) fed a sulphuric acid preserved fish during lactation and growth period. I. A clinical-chemical examination

Addition of sulphuric acid preserved fish in great amounts as fur animal feed has a serious influence on the metabolism of the animals. The present experimental work shows that several clinical-chemical parameters are changed during feeding of acid preserved feed resulting in changes of the fluid-, electrolyte- and acid-base balance as well as in the immunological status. The changes are most probably due to changes also found in the organ functions. The present work together with earlier investigations by the authors has formed the scientific background for the use of acid preserved fish silage in mink during the last 10 years. This has made it possible to out-distance the competitors further, both with respect to fur quality and feeding costs.     

Advances in the mechanism of high copper diets in restraining pigs growth

High copper feed has been widely used as an inexpensive and highly effective feed additive to promote growth performance of pigs. However, long-term feeding of high copper feed may reduce the growth-promoting effects of copper, time-dependent accumulation of copper in animal tissues and organs, and copper toxicity thereby reducing the growth performance of pigs. Due to the widespread effects of high copper supplementation in animals' diets, the benefits and drawbacks of high copper feeding in pigs have been reported in several studies. Meanwhile, few of these studies have systematically described the mechanism by which high copper diets restrain pig growth. Therefore, to address the concerns and give a better understanding of the mechanism of high copper diet in restraining pig growth in different systems, this paper reviews the research progress of long-term supplementation of high copper on the growth of pigs and provides some suggestions and further research directions.     

Systematic analysis of feeding behaviors and their effects on feed efficiency in Pekin ducks

Background: Feeding behavior study is important for animal husbandry and production. However, few studies were conducted on the feeding behavior and their relationship with feeding efficiency in Pekin ducks. In order to investigate the feeding behavior and their relationship with feed efficiency and other economic traits in Pekin ducks, we selected 358 male Pekin ducks and recorded feeding information between 3 to 6 wk of age using automatic electronic feeders, and compared the feeding behavior under different residual feed intake(RFI) levels.Results: We observed that total feed time, daily feed intake and feed intake per meal had strong positive correlations with feed efficiency traits; moreover, strong correlation between feed intake per meal and body weight was found(R=0.32, 0.36). Daily feeding rate meal and meal duration had weak correlations with feed efficiency(R=0.14~0.15). The phenotypic correlation of between-meal pauses, with feed efficiency was not observed. When daily changes were analyzed, high RFI ducks had the highest feed consumption over all times, and obvious differences in daily visits were found among different RFI level animals during the middle period; these differences were magnified with age, but there was no difference in daily meal number. Moreover, our data indicate that high RFI birds mainly take their meals at the edge of the population enclosure, where they are more susceptible to environmental interference.Conclusions: Overal, this study suggests that the general feeding behaviors can be accurately measured using automatic electronic feeders and certain feeding behaviors in Pekin ducks are associated with improved feed efficiency.     

青饲料的卫生与安全饲喂技术研究

青饲料是家畜的重要饲用资源,其适口性好,富含营养素。合理利用青饲料,可以提高家畜养殖生产效益,降低养殖成本。但是,青饲料作物中的一些成分或者在某些条件下的分解、转化产物都会对动物产生毒害作用,从而引起饲料的卫生与安全问题。青饲料中的有毒有害物质包括硝酸盐、亚硝酸盐、生氰糖苷、光敏物质、草酸盐、马铃薯素以及一些牧草中的毒素。对青饲料中所含的有毒有害物质种类及特征进行介绍,对由这些物质引起的动物中毒病的发病机理和救治方法进行综述,在该基础上探讨了青饲料安全饲喂技术,以期为提高青饲料在家畜养殖中的科学饲喂水平提供参考。     

Safety Risks for Animals Fed Genetic Modified (GM) Plants

GM plants are widely grown all over the world, but many constraints still tend to discourage their use in Europe. Potential risks suggested to be associated with the use of GM are unexpected gene effects, allergenic potential, antibiotic resistance, gene flow. GM feed safety is presently evaluated by adopting the concept of GM substantial equivalence, by comparison with non-GM isogenic crops. Comparison is based on a wide spectrum of chemical components and on livestock performance. From the available experimental data, currently utilized GM plants appear safe and show no effects on animals or animal products. Hence, although they potentially exist, safety risks caused by the use of GM plants appear to be so low as be negligible in comparison with their potential benefits, if appropriately designed. GM plants represent a valuable option for future breeding, to increase yield while reducing the use of pesticides, improve plant adaptation to unfavourable environments, and produce better quality crops, also from a nutritional point of view. Nonetheless, GM crops are novel foods and the assessment of their safety using a scientific sound approach seems essential to protect the environment, as well as the health of humans and livestock.