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.     

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.     

转基因植物作为饲料的安全性评价研究

本文综述了转基因植物在全球的发展状况、转基因植物作为动物饲料时存在的风险性、评价转基因饲料的原则和方法、转基因饲料安全性研究的进展状况,对未来转基因植物作为饲料的安全性评价进行了展望。     

Effect of dietary supplementation of recombinant Cry and Cp4 epsps proteins on haematological indices of growing rabbits

Genetically modified (GM) crops expressing insect resistance and herbicide tolerance provide a novel approach for improved crop production but their advent at the same time presents serious challenges in terms of food safety. Although prevailing scientific proof has suggested that transgenic crops are analogous to their conventional counterparts, their use in human and animal diet gave rise to emotional public discussion. A number of studies had been conducted to evaluate the potential unintended effects of transgenic crops expressing single transgene, but very few studies for those with multiple transgenes. As the crops with single and multiple transgenes could impart different effects on non‐target organisms, thus, risk evaluation of transgenic crops expressing more than one transgene is required to declare their biosafety. The present study was therefore designed to assess the effects of different levels of dietary transgenic cottonseed expressing recombinants proteins produced by Cry1Ac, Cry2A and Cp4epsps genes on haematological indices of growing rabbits. A total of 48 rabbits were assigned to four dietary treatments containing different levels of transgenic cottonseeds (i.e., 0% w/w, 20% w/w, 30% w/w and 40% w/w) with 0% w/w serving as control. Haematological parameters were measured at periodic intervals (0, 45, 90, 135 and 180) days. No significant (p > 0.05) dose‐dependent effects were observed in most of the haematological parameters evaluated. Though, significant differences (p < 0.05) were recorded in the level of MCHC, MCH and HCT in some of experimental male and female rabbits, yet, they were not biologically significant, as all the differences were within the normal reference values. Our study suggested that feeding transgenic cottonseed of up to 40% could not adversely affect rabbit's haematological profile. However, further study needs to be conducted with different cotton genotypes expressing both single and polygenic traits before recommending the utilization of transgenic cottonseed in routine livestock feeding.     

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.     

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.     

植物病原镰刀菌产生的毒素种类及其危害

镰刀菌(Fusarium spp.)是多种重要农作物的病原体,不仅可造成农作物产量和品质的严重损失还可在离体培养条件下或植物寄主体内产生一系列被称为镰刀菌毒素的次生代谢产物。这些毒素一方面作为致病因子与镰刀菌对宿主植物的致病力密切相关,另一方面可导致家畜生产性能下降和相关病症的出现,进而影响农业生态系统并对人类健康造成威胁。鉴于镰刀菌毒素对农作物生产的影响及其对家畜和人类的毒性作用,目前已有较多关于镰刀菌侵染粮食作物后产生毒素种类的研究,但关于镰刀菌侵染豆科牧草后产生的毒素种类以及毒素在镰刀菌对豆科牧草致病力方面作用的研究则较少。本文对引起主要粮食和饲料作物病害的常见镰刀菌物种产生的主要毒素,以及这些毒素对植物、家畜和人类的危害进行了综述,并对豆科牧草中镰刀菌毒素的研究前景及意义进行了展望。     

Absence of a Grass/Fire Cycle in a Semiarid Grassland: Response to Prescribed Fire and Grazing

Many nonnative invasive grasses alter fire regimes to their own benefit and the detriment of native organisms. In southern Arizona the nonnative Lehmann lovegrass (Eragrostis lehmanniana Nees) dominates many semiarid grasslands where native grasses were abundant. Managers are wary of using prescribed fire in this fire-prone community partly due to the perceived effects of a grass/fire cycle. However, examples of the grass/fire cycle originate in ecosystems where native plants are less fire-tolerant than grasses and the invasive plant does not mimic the physiognomy of the native community. We investigate the effects of prescribed fire and livestock grazing on a semiarid grassland community dominated by a nonnative invasive grass. Lehmann lovegrass does not appear to alter the fire regime of semiarid grasslands to the detriment of native plants. Prescribed fire reduced the abundance of Lehmann lovegrass for 1 to 2 yr while increasing abundance of native grasses, herbaceous dicotyledons and fall richness, and diversity. Effects of livestock grazing were less transformative than the effects of fire in this long-grazed area, but grazing negatively affected native plants as did the combination of prescribed fire and livestock grazing. Although Lehmann lovegrass produces more fuel than native plants, fire frequency in semiarid grasslands appears to be limited by the paucity of above-average precipitation, which constrains high fuel loads. In addition, many native grasses tolerate high temperatures produced by Lehmann lovegrass fires. Consistent with previous research, fire does not promote the spread of Lehmann lovegrass, and more importantly human alteration of the fire regime is greater than the nominal effects of Lehmann lovegrass introduction on the fire regime.     

Land Manager Perceptions of Opportunities and Constraints of Using Livestock to Manage Invasive Plants

The ecological impacts of rangeland invasive plants have been widely documented, but the social aspects of how managers perceive their impacts and options for control have been relatively understudied, and successful, long-term invasive plant management programs are limited. In particular, though a growing body of research has identified livestock grazing as the most practical and economical tool for controlling invasive rangeland plants, to date there has not been a systematic assessment of the challenges and opportunities producers and other land managers see as most important when considering using livestock to manage invasive plants. In-depth, semistructured interviews with California annual grass and hardwood rangeland ranchers, public agency personnel, and nongovernmental organization land managers were used to address this need. Although interviewees broadly agreed that grazing could be an effective management tool, differences emerged among the three groups in how they prioritized invasive plant control, the amount of resources devoted to control, and the grazing strategies employed. Interviewees identified key challenges that hinder broad-scale adoption of control efforts, including the potential incompatibility of invasive plant management and livestock production; a lack of secure, long-term access to land for many ranchers; incomplete or insufficient information, such as the location or extent of infestations or the economic impacts to operations of invasive plants; and the temporal and spatial variability of the ecosystem. By identifying key socioecological drivers that influence the degree to which livestock are used to manage invasive plants, this study was able to identify potential pathways to move our growing understanding of the science of targeted grazing into practice. Research, extension, and grazing programs that address these barriers should help increase the extent to which we can effectively use livestock to slow and perhaps reverse the spread of some of our most serious rangeland weeds.     

科学规避兽药残留风险的对策措施

笔者对2013?2020年实施的畜产品质量安全监测项目进行多环节系统分析,揭示了主要短板和风险,建议因势利导科学规避兽药残留风险,多策发力提高区域性畜产品质量安全的总体水平。     

麦类作物粮饲兼用研究进展

粮饲兼用是指将营养期作物用于青绿饲草生产(放牧或刈割),待作物再生形成籽粒后收获籽粒的一种生产措施。这一措施已在全球10多个国家和地区广泛应用,以麦类作物的粮饲兼用最为普遍,一定程度上缓解了全球普遍存在的饲草供应季节性不均衡与家畜需求相对稳定的矛盾,促进了畜牧业的持续稳定发展。粮饲兼用的效益优势在于可确保作物籽粒生产的稳定,同时获取额外家畜生产收益。然而,不合理的粮饲兼用会导致饲草及籽粒的产量及品质均会受到影响,有必要开展相关研究以规范化粮饲兼用的应用模式。本文分析了麦类作物粮饲兼用的分布及其效益优势,深入分析了作物类型、播种时间及密度、水热条件等对粮饲兼用生产的影响,归纳得到如下4条技术要点。1)麦类作物可在分蘖期用于适度的利用,保留原有茎尖分生组织可维持籽粒生产的相对稳定。2)应优先选育冬性较强,早期生长缓慢,粮饲兼用不易破坏其茎尖分生组织且花期较晚的高秆品种用于粮饲兼用。3)粮饲兼用作物时,播种时间应提前2~4周,且需适当增加播种密度及提高底肥水平以增加饲草生产;为补偿饲草转移造成的氮亏缺,需在利用后适当添加氮肥以维持其籽粒生产。4)为保证粮饲兼用的效益优势,麦类作物粮饲兼用更适宜于在较湿润的地区(年降水量350~500 mm)开展。本文可为我国深入开展麦类作物粮饲兼用研究提供理论基础,并将进一步指导粮饲兼用措施的应用及推广。     

Review of Methods to Reduce Livestock Depradation: I. Guardian Animals

The use of domestic animals to protect livestock was reviewed through visits to actual users, discussions with experts and a thorough literature search. Costs and benefits were analysed in terms of reduced livestock losses. The most common guardian animals are dogs, which have been shown to reduce predation (documented mostly for coyote) by 11?100%. Livestock guardian dogs have also been used effectively against bear, wolf and cheetah. Donkeys are also used as guardian animals, and their effectiveness lies in their natural herding behaviour and aggression, especially against canids. The effectiveness of donkeys varies considerably dependent upon the predator species and the temperament of the individual donkey. Llamas are also used as a guardian animal, with approximately the same characteristics as the donkeys, and will defend themselves against most predators. The use of guardian animals appears to be an effective tool for reducing livestock depredation and should be evaluated in areas with high predation losses against the cost of changing production systems.     

科尔沁草地有毒植物及保障家畜安全的对策

为了保障家畜采食安全,对科尔沁草地有毒植物进行了大量的调查和资料整理,初步查明了科尔汤草地有毒植物植物共１６４种,隶属于４２科９３属,首次对这些有毒植物进行了生活型和水分生态类型分析,结果表明：有毒植物以多年生中生、中时时生草本植物占多数;在水分条件相对较好的草地类型或局部地段有毒植物分布较多,较常见的有毒植物所含有的主要毒物成分为生物碱、甙类化合物、匝类化合物、酚类及其衍生物、无机物和简单有机舶     

白藜芦醇对畜禽骨骼肌纤维类型转化的影响及其机理

白藜芦醇是自然界中广泛存在于葡萄、花生等植物中的一类多酚类化合物,具有广泛的生物学活性,如抗氧化、抗肿瘤、抗衰老、保护心血管等。近年来,白藜芦醇在骨骼肌纤维类型转化上的功能研究也得到越来越多的关注。研究表明,白藜芦醇能诱导酵解型肌纤维向氧化型肌纤维的转化,从而达到改善禽畜肉质的目的。本文将综合最新研究报道,总结白藜芦醇对骨骼肌纤维类型转化的影响及其可能的作用机理,为其在畜牧生产上的应用提供理论基础。     

Bacterial typing methods suitable for epidemiological analysis. applications in investigations of salmonellosis among livestock

Summary

The ability to subtype bacteria by typing methods provides the bacteriologist with a powerful means to identify relationships between bacteria. This knowledge is used to identify routes of disease transmission among livestock and from livestock to humans. In the present paper, the principles of bacterial typing and the most commonly applied typing methods for use in veterinary public health are discussed in the context of their application in the investigation of salmonella epidemiology. Typing methods are now routinely used in most investigations on this subject and have provided insight into routes of transmission, reservoirs of infection and mechanisms of persistent infection.

Under the EC order on zoonotic diseases, extended surveillance on the presence of zoonotic bacteria in livestock must be expected. To receive the maximum benefits of this surveillance, selected typing methods must be applied to all isolates of e.g. salmonella. At present, serotyping, and phage typing where applicable, are the most obvious choices for continuous surveillance of this organism. Random amplification of polymorphic DNA (PCR based typing) may have the potential for allocating strains into relevant groups quicker and without the requirement for additional manpower, and this method may be preferred in future.     

A survey to investigate movements off sheep and cattle farms in New Zealand,with reference to the potential transmission of foot-and-mouth disease

AIM: To quantify the numbers and extent of movements off sheep and cattle farms in New Zealand, in order to construct more realistic simulation models to investigate how infectious diseases such as foot-and-mouth disease (FMD) might spread.

METHODS: Farmers from 500 randomly selected farms, comprising 100 from each of the following sectors, viz beef, dairy, grazing/dairy heifer rearing, sheep, and mixed sheep and beef, were asked to fill in diaries in which they recorded the movements of all animals, products, people, vehicles and equipment coming on to or leaving their farms during two separate 3-week periods, representing relatively ‘busy’ and ‘quiet’ times of the year with respect to livestock movements. Where possible, the destination of each movement was identified and geo-coded, to allow the distance travelled to be calculated. Each movement was then classified according to the risk of transfer of FMD virus (FMDV), should the disease have been present on the study farm at the time of the movement. The data were then analysed to establish movement frequencies and distributions of distances travelled, by the different pastoral livestock sectors.

RESULTS: Two hundred and seventeen farmers returned one or more diaries. One hundred and ninety-three farmers completed a Busy-period diary, recording a total of 12,052 movements off their farms, a crude average of 62.4 per 3-week period, or 2.97 per day. Of these, 4.0% involved the transport of livestock, equating to 0.12 livestock consignments per day. In contrast, 186 Quiet-period diaries were returned, recording a total of 10,885 movements off, representing a crude average of 58.5 during the 3-week period, or 2.78 per day. Of these, 2.1% involved livestock, equating to 0.06 livestock consignments per day. The mean and median distances travelled during the Busy periods were 30.9 km and 13.1 km, respectively (range 0–1,167 km). In comparison, the mean and median distances travelled during Quiet periods were 41.3 and 14 km, respectively (range 0.4–1,203 km).

CONCLUSIONS: People, vehicles, livestock and other items can travel off pastoral livestock farms in New Zealand to other farms either directly or via saleyards over extensive distances. This has implications for the potential spread of infectious diseases such as FMD. Movement parameters intended for use in the InterSpread Plus inter-farm simulation model of FMD were established, which will facilitate the prediction of likely spread and efficacy of controls in the unlikely event of a real-life outbreak.     

Assimilation Versus Accumulation of Macro- and Micronutrients in Soils: Relations to Livestock and Poultry Feeding Operations

Nutrient management is an integral part of profitable agrisystems, but in some areas of the United States, continued applications of fertilizer and manure nutrients in excess of crop requirements have led to a buildup of nutrient concentrations that are of environmental concern. Proper use of nutrients in livestock manures is becoming more critical for sustainability of concentrated animal feeding operations (CAFO) because new environmental regulations require that nutrients be properly applied and managed. Losses of nutrients, such as N and P can be reduced by refining the rations fed, increasing nutrient retention by livestock, moving manures from areas of surplus to deficiency, finding alternative uses for manure, using cropping and haying systems that remove excess nutrients, and using conservation practices, such as limited tillage, buffer strips, and cover crops to limit runoff and leaching. Whole farm nutrient balances are useful for educating producers about quantities of nutrients being managed and the flow of nutrients, but they can also be misleading because of spatial factors, such as uneven nutrient application that introduce environmental risks that may not be noted with a whole-farm nutrient balance. Manure utilization plans also need to deal with nutrients that potentially leave the field or production area in route to sensitive ecosystems.     

Board-invited review: Applications of genomic information in livestock

The availability of whole genome sequences for individual species will change the landscape for livestock genomic research. Animal scientists will have access to whole-genome sequence-based technologies such as high-throughput SNP genotyping assays, gene expression profiling, methylation profiling, RNA interference, and genome resequencing that will revolutionize the scale upon which research will be conducted. These technologies will also alter the ways we think about addressing industry and scientific problems. In this review, we discuss the scientific bases for these emerging technologies and present recent highlights of their application in human, model species, and livestock as well as their potential for future applications in livestock. Additionally, we discuss strategies for their use in the genetic improvement and management of livestock. In particular, we present a strategy for the simultaneous identification of causal mutations underlying phenotypic traits in livestock and discuss issues that will arise in the application of whole genome selection for the prediction of genetic merit in livestock. We also point out that the statistical analysis that underlies the whole genome selection methodology is a sophisticated enhancement of single marker association mapping analysis to allow the entire genome to be simultaneously analyzed.     

Risks connected with the use of conventional and genetically engineerd vaccines

Summary

A review is given of real and potential risks connected with the use of conventional and genetically engineered live and dead vaccines. Special attention is given to live carrier vaccines expressing one or more heterologous genes of other microorganisms. Because most carrier vaccines are still in an experimental phase, there is only limited experience with the risks of carrier vaccines. There are three potential risks of live carrier vaccines which will be discussed:

1. Changes in cell, tissue, of host tropism, and virulence of the carrier through the incorporation of foreign genes.

2. Exchange of genetic information with other vaccine or wild‐type strains of the carrier organism.

3. Spread in the environment.

Only limited experimental data are available on changes in biological behaviour of microorganisms through the incorporation of foreign genes. For example, there are indications that vaccinia virus carrying the attachment protein G of respiratory syncytial virus (RSV) replicates better in lungs of mice than vaccinia virus carrying other genes of RSV. Poxviruses carry genes that probably determine their replication in different hosts. Exchange of such host tropism genes might alter their host spectrum. Recombination between herpesvirus vaccine or wildtype strains may lead to the appearance of virulent strains with of without heterologous genes. Before carrier vaccines are applied, these risks must be thoroughly evaluated case‐by‐case. Potential methods for the design of safe carrier vaccines are discussed.

This article is based on a contribution to the course ‘Introduction of Genetically Modified Organisms into the Environment: Biosafety Aspects’, 4–14 December 1991, Wageningen, the Netherlands.     

Use of Camelina sativa in the Diets of Young Turkeys

Camelina sativa is one of various oilseed crops being studied for its potential value in biofuel production. The resultant by-product of oil extraction, camelina meal (CM), could be marketable as a livestock feed. Our study evaluated the potential use of CM as a feed ingredient in turkey poult starter diets. This was a pilot study to determine whether further work investigating inclusion of CM as a potential feed ingredient in turkey diets might be of value if a least-cost formulation warranted its integration. Results indicate that CM may be a potentially useful minor ingredient in turkey diets if economically feasible, but caution should be exercised in using CM above 5% of finished feed in a poult starter diet. In an appended test, similar weight gain and feed conversion were attained with a diet containing camelina oil as a replacement for vegetable oil compared with the control diet.