Perspectives from agriculture: advances in livestock breeding - implications for aquaculture genetics

In this paper we present livestock breeding developments that could be taken into consideration in the genetic improvement of farmed aquaculture species, especially in freshwater fish. Firstly, the current breeding objective in aquatic species has focused almost exclusively on the improvement of body weight at harvest or on growth related traits. This is unlikely to be sufficient to meet the future needs of the aquaculture industry. To meet future demands breeding programs will most likely have to include additional traits, such as fitness related ones (survival, disease resistance), feed efficiency, or flesh quality, rather than only growth performance. In order to select for a multi-trait breeding objective, genetic variation in traits of interest and the genetic relationships among them need to be estimated. In addition, economic values for these traits will be required. Generally, there is a paucity of data on variable and fixed production costs in aquaculture, and this could be a major constraint in the further expansion of the breeding objectives. Secondly, genetic evaluation systems using the restricted maximum likelihood method (REML) and best linear unbiased prediction (BLUP) in a framework of mixed model methodology could be widely adopted to replace the more commonly used method of mass selection based on phenotypic performance. The BLUP method increases the accuracy of selection and also allows the management of inbreeding and estimation of genetic trends. BLUP is an improvement over the classic selection index approach, which was used in the success story of the genetically improved farmed tilapia (GIFT) in the Philippines, with genetic gains from 10 to 20 per cent per generation of selection. In parallel with BLUP, optimal genetic contribution theory can be applied to maximize genetic gain while constraining inbreeding in the long run in selection programs. Thirdly, by using advanced statistical methods, genetic selection can be carried out not only at the nucleus level but also in lower tiers of the pyramid breeding structure. Large scale across population genetic evaluation through genetic connectedness using cryopreserved sperm enables the comparison and ranking of genetic merit of all animals across populations, countries or years, and thus the genetically superior brood stock can be identified and widely used and exchanged to increase the rate of genetic progress in the population as a whole. It is concluded that sound genetic programs need to be established for aquaculture species. In addition to being very effective, fully pedigreed breeding programs would also enable the exploration of possibilities of integrating molecular markers (e.g., genetic tagging using DNA fingerprinting, marker (gene) assisted selection) and reproductive technologies such as in-vitro fertilization using cryopreserved spermatozoa

Proceedings of a workshop on the development of a genetic improvement program for African catfish Clarias gariepinus

This proceedings include papers present at the workshop held from 5 to 9th Nov 2007 in Accra, Ghana. The areas cover 1)the present state of the catfish industry in Africa 2)Catfish reproductive management and grow out 3)Catfish nutrition and feeds 4)The application of genetic principles to catfish genetic improvement programs 5)Recommendations on how to best approach the issue of genetic improvement programs for catfish.Genetics, Biotechnology, Reproduction, Biological production, Nutrition Clarias gariepinus

Perspectives from Agriculture: Advances in livestock breeding-Implications of aquaculture genetics

In this paper we present livestock breeding developments that could be taken into consideration in the genetic improvement of farmed aquaculture species, especially in freshwater fish. Firstly, the current breeding objective in aquatic species has focused almost exclusively on the improvement of body weight at harvest or on growth related traits. This is unlikely to be sufficient to meet the future needs of the aquaculture industry. To meet future demands breeding programs will most likely have to include additional traits, such as fitness related ones (survival, disease resistance), feed efficiency, or flesh quality, rather than only growth performance. In order to select for a multi-trait breeding objective, genetic variation in traits of interest and the genetic relationships among them need to be estimated. In addition, economic values for these traits will be required. Generally, there is a paucity of data on variable and fixed production costs in aquaculture, and this could be a major constraint in the further expansion of the breeding objectives. Secondly, genetic evaluation systems using the restricted maximum likelihood method (REML) and best linear unbiased prediction (BLUP) in a framework of mixed model methodology could be widely adopted to replace the more commonly used method of mass selection based on phenotypic performance. The BLUP method increases the accuracy of selection and also allows the management of inbreeding and estimation of genetic trends. BLUP is an improvement over the classic selection index approach, which was used in the success story of the genetically improved farmed tilapia (GIFT) in the Philippines, with genetic gains from 10 to 20 per cent per generation of selection. In parallel with BLUP, optimal genetic contribution theory can be applied to maximize genetic gain while constraining inbreeding in the long run in selection programs. Thirdly, by using advanced statistical methods, genetic selection can be carried out not only at the nucleus level but also in lower tiers of the pyramid breeding structure. Large scale across population genetic evaluation through genetic connectedness using cryopreserved sperm enables the comparison and ranking of genetic merit of all animals across populations, countries or years, and thus the genetically superior brood stock can be identified and widely used and exchanged to increase the rate of genetic progress in the population as a whole. It is concluded that sound genetic programs need to be established for aquaculture species. In addition to being very effective, fully pedigreed breeding programs would also enable the exploration of possibilities of integrating molecular markers (e.g., genetic tagging using DNA fingerprinting, marker (gene) assisted selection) and reproductive technologies such as in-vitro fertilization using cryopreserved spermatozoa.Genetics, Biotechnology, Selective breeding

Genetic improvement and effective dissemination: keys to prosperous and sustainable aquaculture industries

There is an increasing demand for fish in the world due to a growing population, better economic situation in some sectors, and greater awareness of health issues in relation to food. Since capture fisheries have stagnated, fish farming has become a very fast growing food production system. In this presentation, the author gives an overview of the technologies that are available for genetic improvement of fish, and briefly discuss their merit in the context of a sustainable development. He also discusses the essential prerequisites for effective dissemination of improved stock to farmers. It is concluded that genetic improvement programs based on selective breeding can substantially contribute to sustainable fish production systems. Furthermore, if such genetic improvement programs are followed up with effective dissemination strategies, they can result in a positive impact on farmers' incomes

Considerations about effective dissemination of improved fish strains

Aquaculture production systems in developing countries are largely based on the use of unimproved species and strains. As knowledge and experience are accumulated in relation to the management, feeding and animal health issues of such production systems, the availability of genetically more productive stock becomes imperative in order to more effectively use resources. For instance, there is little point in providing ideal water conditions and optimum feed quality to fish that do not have the potential to grow faster and to be harvested on time, providing a product of the desired quality. Refinements in the production system and improvement of the stock used must progress hand in hand. In this paper we deal separately with genetic and non-genetic issues pertaining to the multiplication and dissemination of improved strains. The separation is somewhat arbitrary, and as will be evident from our discussion, there is frequent interaction between the two

Development of aquatic animal genetic improvement and dissemination programs : current status and action plans

Aquatic animals, Breeding, Genetics, Fish

Multi-target detection and recognition by UAVs using online POMDPs

This paper tackles high-level decision-making techniques for robotic missions, which involve both active sensing and symbolic goal reaching, under uncertain probabilistic environments and strong time constraints. Our case study is a POMDP model of an online multi-target detection and recognition mission by an autonomous UAV.The POMDP model of the multi-target detection and recognition problem is generated online from a list of areas of interest, which are automatically extracted at the beginning of the flight from a coarse-grained high altitude observation of the scene. The POMDP observation model relies on a statistical abstraction of an image processing algorithm's output used to detect targets. As the POMDP problem cannot be known and thus optimized before the beginning of the flight, our main contribution is an ``optimize-while-execute'' algorithmic framework: it drives a POMDP sub-planner to optimize and execute the POMDP policy in parallel under action duration constraints. We present new results from real outdoor flights and SAIL simulations, which highlight both the benefits of using POMDPs in multi-target detection and recognition missions, and of our`optimize-while-execute'' paradigm

The “edulibrarian”

There are no doubts: Information, Knowledge and Learning are the key words of our era. Always during the time, our profession has had a specific mission: to serve the needs of the society; nowadays, more than ever, user must be the center of our operating. We have no choice: in order to survive and in order to continue to be indispensable, we must adapt ourselves to the contemporary world. It should not be a strain, but a stimulus! We wanted to travel around and into the specialized literature, looking for new roads to run, for new professional stimuli to enjoy, for innovated roles to cover. The paradox of a society which defines itself through the power of information, communication and learning, reducing at the same time our profession as something “optional”, needs to be understood by us: if we know the problem, as Reflective Information Professionals we can solve it. It's on us, it's our responsibility: we can make society understood we are indispensable. What's the way to achieve it? This literature review is about it

The contributions of junctions and nanowires/nanotubes in conductive networks

Electrical transport in networked materials occurs through percolative clusters composed of a random distribution of two kinds of interconnected elements: elementary nanostructures and nanostructure-nanostructure junctions. Rationalizing the contribution of these microscopic elements to the macroscopic resistance of the system is a fundamental issue to develop this class of materials and related devices. Focusing on networks composed of high-aspect-ratio nanostructures, such as nanowires (NWs) or nanotubes (NTs), these concepts are still raising controversy in modeling and interpretation of experimental data. Despite these incongruences and the large variations induced by disorder in the electrical properties of such networked systems, this work shows that the ratio between the junction and the nanostructure resistance is nearly the same at the microscopic and macroscopic levels, regardless of the network features. In other words, this means that we may assess the relative contribution of nanostructures and junctions to the macroscopic network resistance directly from the knowledge of its microscopic building blocks. Based on experimental data available in the literature, this result is proven to hold for different materials and network densities, ranging from inorganic NWs to organic carbon NTs and from the percolation critical density nc up to, at least, five times nc, respectively

Creating Space:Enabling inclusion in social policy through participatory research

Boutellier, J.C.J. [Promotor]Pels, T.V.M. [Promotor