This chapter was published on “Inuitech –
Intuitech Technologies for Sustainability” on February 12, 2012.
The world is faced with crucial challenges to ensure food security. The reality is that
the amount of available animal protein for human consumption at a global level
is already limited. Additionally, the increased movement of animals and animal products due to expanding world trade and the growing effects of climate change making the fragile food security further exacerbated. There is a strong possibility that these effects may result in changes in the geographical distribution of pathogens and their vectors.
At the same time, there is a recognition that assisting smallholder farmers in developing countries to improve the utilization of locally available land, water, and plant resources in order to intensify and increase animal production is critical to ensuring food security for a world population that will grow to over eight billion in the next twenty years.
Perhaps another noteworthy factor to consider is that resource-poor developing countries will become increasingly vulnerable to emergencies caused by the growing prevalence of infectious diseases, especially transboundary animal diseases (TADs). A complicating factor is that more than 60 percent of the TADs are zoonotic diseases, diseases of animal origin that infect humans, such as Human Immunodeficiency Virus (HIV), H5N1 (Avian Influenza) and H1N1 (Swine Flu), Rabies, Rift Valley Fever, and Trypanosomosis.
It is envisioned that in order to improve livestock productivity as well as health while minimizing the vulnerability to emergencies caused by the growing prevalence of infectious diseases, it will require not only more sustainable livestock production, but also more efficient approaches, meaningful tools, and realistic strategies for preventing, diagnosing and controlling animal diseases around the world.
Unfortunately, classical or traditional techniques for diagnosing threatening diseases are well in place, but often lack the sensitivity and specificity needed to make accurate and timely diagnoses of diseases. Nuclear and nuclear related technologies have these features and are therefore increasingly being used to complement traditional diagnostic and tracing technologies to improve the early and rapid diagnosis and control of animal diseases through tracing and vaccination strategies. The IAEA, through the development and application of nuclear and nuclear-related technologies, is at the forefront of developing and validating early and rapid diagnostic techniques. These techniques are:
- Simple to use, inexpensive and can be applied in a “laboratory limited” environment, such as those located in rural and decentralized areas;
- In the tracing of diseases through the application of stable isotope techniques; and
- In the application of irradiation technologies to provide safe and user friendly vaccines.
Nuclear applications for improving livestock productivity and health have driven modern biotechnological research by providing more sensitive, specific and cost effective diagnostic platforms or assays to detect and characterize the disease pathogens. Many of these nuclear-based applications are being used in IAEA Member States for diagnosis of TADs such as rinderpest and rabies. The use of nuclear technologies allows the detection and characterization of pathogens within 24 hours of their onset, helping to differentiate one particular virus strain from another. An example of this differentiation is noted in the case of the Influenza AH1N1 virus, from Influenza AH5N1. Nuclear techniques are also important in determining the nucleic acid sequence that describes the capacity of a particular virus strain to cause a disease.
The application of nuclear technologies, in combination with conventional technologies, has contributed to concrete improvements in the number, condition and health of animals resulting in improved livelihoods for millions of people worldwide. For example, according to the Food and Agriculture (FAO), it is estimated that the eradication of rinderpest saves Africa more than 1 billion USD per year. The unique characteristics of nuclear technologies not only contribute to the efforts to reduce transboundary animal disease risks, but also to the tracing and monitoring of animal movements (e.g. the tracing of disease infected migratory birds), as well as to the timely and proactive control and prevention of diseases through the use of vaccines.
The FAO together with the World Organization for Animal Health (OIE) have identified the analysis of animal genetic resources as a high priority area since it provides crucial options for the sustainable development of livestock production and for enhancing food security. Sustainable livestock production, refers the farming of animals using a system that ensures (or at least favours) the long-term availability of the inputs necessary to continue in operation, along with satisfactory returns for the farmer. Unsustainable practices are those that cause damage to the environment, increased risk for disease, decreased genetic variation and dissatisfaction by consumers, not to mention disenchantment by the producer.
Nuclear technologies are used in many areas of livestock research and production. For example, the use of isotopic tracer techniques to measure the nutritive value of feedstuff, to determine the nutrient intake or energy balance of animals, and to study the metabolism of nutrients in the animal body. The output of research helps to formulate balanced diets to achieve efficient growth and production. Isotopic methods are also used to monitor reproductive status, leading to better breeding management. Moreover, nuclear techniques are also used in livestock disease diagnosis.
As a definition, ISOTOPES represent one of two or more atoms having the same atomic number but different mass numbers. Isotopic technologies present major advantage in measuring reactions very precisely and accurately. Therefore, they are still in use in scientific research work to produce for instance better diagnostic tools and tests or to follow the metabolite of a drug through the body. Better diagnostic tools help in early diagnosis of diseased animals while better drugs or vaccines help in reducing the losses due to the pathogen.
According to the International Atomic Energy Agency (IAEA), historically, radioimmunoassay has been the dominant technology in this field. The RIA employs radioisotopes in the measurement of the concentration of a given molecule in a biological sample. For reproduction, the most commonly measured molecule has been progesterone and its measurement has allowed for monitoring of the reproduction cycle of livestock and improvement of the efficiency of artificial insemination programs.
Some examples of isotopic techniques are:
- Stable- (15N) and radio-isotope (35S or 32P) incorporation methods for measuring microbial mass in vitro and in vivo, enabling the selection of feeds based on the efficiency of microbial protein production;
- 125I-labeled bovine serum albumin and 14C-labeled polyethylene glycol assays for measuring tannin in feeds;
- A method based on the feeding of isotope-labeled protein (15N or 125I) complexed with tannin for ranking different tannins for their abilities to release protein for digestion in vivo;
- 14C-uric acid and 14C-allantoin infusion methods for development of models describing excretion of purine derivatives in urine and microbial protein supply to ruminants, which permit assessment of nutritional status of animals and determination of nutritional quality of feed resources;
- A 15N isotope dilution technique using 15N-leucine to distinguish feed and endogenous secretions at the ileum, for determination of true digestibility of protein-rich tree leaves and aquatic plants in pigs;
- Progesterone radioimmunoassay (RIA) for enhancing reproductive efficiency of ruminants, and RIA based leptin and insulin growth factor assays for assessing the nutritional status of animals;
- Feeding of 15N enriched plant material to generate 15N-labeled excreta for research on the fate of excreta N in the environment;
- 15N, 13C and 34S isotopic methods for nutrient budgeting and for following the nutrient pathways in soil-plant-animal continuum;
- 32P- or 33P-labeled fertilizers for estimating the efficiency of P utilization in legume leaf production used for livestock feeding;
- Doubly labeled water (18O and 2H labeled) method for estimation of energy expenditures of grazing animals, body composition, basal metabolic rate, and milk output in cows with calves;
- NaH13CO3/ NaH14CO3 infusion for estimation of the carbon dioxide production which in turn is used to estimate energy expenditure in free-ranging animals;
- 3H- or 14C-labelled methane and 14C-labeled volatile fatty acids dilution technique for direct and indirect (using stoichiometry of carbohydrate fermentation) respectively for determination of methane emission from livestock; and
- 15N dilution technique requiring labeling the soil with 15N fertilizer (15N-ammonium sulphate or 15N-urea) for estimation of nitrogen fixation by leguminous trees and pastures, for better management of pastures and efficient integration of cereal crops with the fodder crops.
With support from the IAEA, important progress has been made in the analysis of genetic diversity in cattle, sheep and goat breeds, to improve the selection of desirable animals for higher productivity as their ability to resist endemic diseases or harsh environments is in many cases linked to their genetic make-up. The data and results from such genetic analyses are valuable for ensuring the sustainability of future animal breeding programmes and their ability to select animals that carry suitable genes. However, there are significant gaps in capacity for using the genetic data from these analyses for animal breeding programmes, particularly in developing countries. To this effect, a computer system with the network interface capability was developed to make available the genetic data to all IAEA Member States, and to provide access to laboratory protocols, standard operating procedures for gene analysis, tools for genome searches, and a livestock molecular markers database. Genomic and phenotypic data have been acquired from over 4000 sheep and goats of 89 breeds. This data will be used to identify common genes that could be exploited for improving animal production.
Radiolabelled nucleotide probes have contributed to the sequencing of the full bovine genome14. These tools provide a means for the selection of more energy efficient animals with a smaller environmental footprint, and in particular animals that produce less greenhouse gas emissions. This discovery could lead to more efficient meat and milk production, and provides new information about the evolution of mammals as well as on cattle-specific biology. It also indicates the direction for research that could result in more sustainable food production in a world challenged by global population growth.
Nuclear technologies are also vital to animal disease diagnosis where rapid decision-making would be an advantage and especially in situations where the suspected disease occurs in difficult to reach or remote areas that are far from the laboratory. The time saved by determining whether a disease is present or not, could be the difference between containing a disease at its point of origin and protecting human lives or preventing the spread of a disease to an animal market place or further afield. Conventional molecular techniques including thermal amplification or PCR require sophisticated, expensive equipment. A robust test at the molecular level, i.e. the loop mediated isothermal amplification (LAMP) PCR, has been developed using nuclear techniques, which is a more cost effective alternative to thermal DNA amplification. The LAMP PCR can be carried out within 30 to 60 minutes in a simple water bath at constant temperature and the presence or absence of the isothermally amplified DNA product can be detected visually, i.e. a change in colour. Another advantage of the LAMP PCR platform is that it can be developed for use on-site or on farm as a penside (point of care) rapid diagnostic test.
The world continues to demand more and healthier animals and animal products that are environmentally safe, clean and ethical. This demand poses far-reaching challenges for animal scientists on the critically important need to improve technologies in animal production and health in order to ensure food security, poverty alleviation and environmental protection on a global scale.
Nuclear applications drive modern biotechnological research by providing more sensitive, specific and cost effective diagnostic platforms or assays to detect and characterize disease pathogens. The application of nuclear technologies – in combination with conventional technologies – contributes to improvements in the number, condition and health of animals resulting in improved livelihoods of millions of people worldwide.
- Reducing the risk of transboundry animal diseases through Nuclear Technologies;
- IAEA Nuclear Techniques in Food and Agriculture – FAQs;
- IAEA Nuclear Techniques in Food and Agriculture – FAQs;
- IAEA Nuclear Techniques in Food and Agriculture – FAQs;
- IAEA Nuclear Techniques in Food and Agriculture – FAQs; and
- Nuclear Technology Review 2010.