Design of fish breeding programs (original) (raw)
THE SIGNIFICANCE OF SELECTIVE BREEDING IN AQUACULTURE TO SATISFY THE DEMAND FOR FISH
BREEDING, 2025
Aquaculture plays a vital role in meeting the rising global demand for fish as a source of protein and essential nutrients. As the world's population continues to grow, sustainable aquaculture practices are crucial for ensuring food security and reducing pressure on wild fish stocks. Selective breeding is a powerful tool that has been increasingly utilized in aquaculture to improve the productivity, sustainability, and quality of farmed fish populations. This review paper explores the significance of selective breeding in aquaculture and its role in satisfying the increasing demand for fish. By selectively breeding fish for desirable traits such as fast growth, disease resistance, feed efficiency, and fillet quality, aquaculture producers can enhance the overall performance of farmed fish stocks. Improved growth rates, higher disease resistance, and better feed conversion efficiency achieved through selective breeding contribute to increased productivity and profitability in aquaculture operations. Furthermore, selective breeding programs in aquaculture help address environmental concerns by promoting sustainable production practices. By focusing on traits that reduce environmental impact, such as efficient feed utilization and reduced waste production, selective breeding can contribute to more environmentally friendly and resource-efficient fish farming operations. The preservation of genetic diversity within farmed fish populations is also emphasized through selective breeding efforts, ensuring the long-term resilience and adaptability of fish stocks to changing environmental conditions. One notable example of the success of selective breeding in aquaculture is the development of the Genetically Improved Farmed Tilapia (GIFT) strain, which has demonstrated significant improvements in growth rate, disease resistance, and fillet quality. The adoption of GIFT tilapia and other genetically improved strains has helped increase production levels, reduce production costs, and meet the demand for highquality and sustainably produced fish products. In conclusion, selective breeding in aquaculture is essential for enhancing the productivity, sustainability, and quality of farmed fish populations in response to the growing global demand for fish. By harnessing the power of selective breeding, aquaculture producers can contribute to food security, environmental sustainability, and economic development in the aquaculture sector. Continued research and innovation in selective breeding techniques are key to further advancing the aquaculture industry and ensuring a reliable supply of nutritious and responsibly sourced fish for future generations.
Selective breeding in fish and conservation of genetic resources for aquaculture
Reproduction in Domestic Animals
To satisfy increasing demands for fish as food, progress must occur towards greater aquaculture productivity whilst retaining the wild and farmed genetic resources that underpin global fish production. We review the main selection methods that have been developed for genetic improvement in aquaculture, and discuss their virtues and shortcomings. Examples of the application of mass, cohort, within family, and combined between-family and within-family selection are given. In addition, we review the manner in which fish genetic resources can be lost at the intra-specific, species and ecosystem levels and discuss options to best prevent this. We illustrate that fundamental principles of genetic management are common in the implementation of both selective breeding and conservation programmes, and should be emphasized in capacity development efforts. We highlight the value of applied genetics approaches for increasing aquaculture productivity and the conservation of fish genetic resources.
Toward the Genetic Improvement of Feed Conversion Efficiency in Fish
Journal of the World Aquaculture Society, 2003
Feed conversion efficiency (FCE) is the effectiveness with which feed is converted to saleable fish product. Feed costs are a major input to aquaculture production systems, and genetic improvement in FCE may therefore have an important influence on profitability. FCE is usually expressed by a composite measure that combines feed intake and growth rate. The two most common measures are feed conversion ratio (feed intake/weight gain over a specified time interval) and its inverse, feed efficiency. Feed conversion ratio and feed efficiency are measures of gross FCE, because they do not distinguish between the separate energy requirements of growth and maintenance. There is abundant evidence of substantial genetic variation in FCE and its component traits in terrestrial livestock species and, although data are few, the same is likely for cultured fish species. The major problems with selecting from this variation to genetically improve FCE in fish species are: 0 It appears impractical to measure feed intake on individual fish, so that family mean data We do not know the optimal time period over which to test fish for FCE. 0 We do not know the genetic correlations between FCE under apparent satiation or re-If these problems can be overcome, selection to improve FCE might be best achieved by measuring feed intake of growing animals, and by utilizing genetic correlations that are likely to exist between feed intake and other production traits to develop a weighted selection index. must be used. stricted intake conditions, or between FCE at different times in the production cycle.
A Review on Genetic Improvement in Aquaculture through Selective Breeding
Journal of advances in biology & biotechnology, 2024
Aquaculture is the farming of aquatic organisms such as fish, crustaceans, molluscs, and aquatic plants. Selective breeding is a key tool used in aquaculture to improve the genetic makeup of farmed species and enhance their productivity and desirable traits. This review explores the application of quantitative genetic principles in fish breeding, which has advanced more slowly compared to livestock breeding. Traditional fish breeding designs are often complicated by confounding effects, making it necessary to modify standard practices to distinguish additive, maternal, and non-additive genetic influences for effective genetic improvement. Selective breeding is essential in aquaculture, offering rapid selection responses and significant genetic gains. Despite the economic importance of traits in aquaculture species, there is limited knowledge of their phenotypic and genetic parameters due to underdeveloped breeding programs. This review highlights various selective breeding programs for key species such as salmon, trout, tilapia, and carp. Carp breeding, crucial in Indian aquaculture, has demonstrated substantial growth rate enhancements through selective breeding. The review underscores the potential of selective breeding to enhance economically significant traits in aquaculture, emphasizing the need for ongoing research and development in genetic improvement strategies.
Recent advances in animal breeding theory and its possible application in aquaculture
SUMMARY - The genetic change of the population mean of a quantitative trait is the outcome of the action of two antagonistic forces: artificial or natural selection and genetic drift. The latter may generate inbreeding depression and erosion of the genetic variance, both for production and fitness traits. Inbreeding changes are cumulative and inversely proportional to the effective population size. To keep undesirable inbreeding effects in check, a minimum number of selected parents larger than that required to produce the desired offspring number should be used. Moreover, the variability of selection response is also inversely proportional to the effective size. Thus, a reasonable chance of success of achieving some response can only be attained by further increasing the effective size. In parallel, the magnitude of short-term selection response depends linearly on the accuracy of selection. Efficient selection methods rely on the use of family information through BLUP evaluation. ...
The aim of this review was to highlight the extent to which the genetic technologies are implemented by the aquaculture industry. The review shows that some of the modern genetic technologies are already extensively applied by the diverse aquaculture industries, though not to the same extent for all important aquacultured species (according to FAO 1998 figures). Some species (common carp, Atlantic salmon, rainbow trout, channel catfish, Nile tilapia, and the Pacific oyster) received concentrated breeding efforts, while other major cultured species (Chinese and Indian carps and the giant tiger shrimp) received, so far, relatively limited attention, and a few species (Yesso scallop, blue mussel, white Amur bream, and milkfish) have, apparently, not been genetically improved at all. Most of the genetically improved strains reaching the aquaculture industry were developed through traditional selective breeding (selection, crossbreeding, and hybridization). Emerging, more modern technologies for genetic manipulation seem to take 10–20 years from being established experimentally until applications affect the industry. Thus, chromosome-set and sex manipulations started to affect the industry during the 1980's and 1990's. DNA marker technology and gene manipulations have yet hardly affected the industry. The former have not matured yet, but hold much promise. The latter could have affected the industry already had it not been restricted by public concern.
Aquaculture, 2016
In this simulation study, the effect of the mating scheme on genetic gain and inbreeding has been explored for aquaculture selection programs where tank effects and large family sizes are common. Different selection methods were investigated (individual, family, sib, combined and within-family selection). Our results suggest that under family and sib selection, genetic gain was increased with assortative mating in comparison to random mating. The advantage of assortative mating increased when common environmental effects were present. Contrarily, a decrease in genetic gain was observed with disassortative mating, except for the case of within-family selection. The advantage of assortative mating over random mating was due to the increase in the betweenfamily component of the additive genetic variance that was exacerbated with the presence of common environmental effects. Under family and sib selection, the join effect of assortative mating and common environmental effects produced an increase in genetic gain of around 80 and 40% at early generations, and around 10 and 60% at later generations, respectively. Inbreeding was low under family selection for all mating schemes but much higher under sib selection when assortative mating was performed. In fact, the inbreeding coefficient after 10 generations of selection was 300% higher when assortative matings were performed under sib selection, compared to random matings. This was due to the fact that under sib selection, matings were based on family means, leading to an increased frequency of within-family matings. To our knowledge, this is the first study that investigates the effect of the mating scheme on genetic gain and inbreeding in an aquaculture context where family sizes are large and tank effects are present, and shows that assortative mating can substantially enhance the response to selection, particularly when family selection methods are applied. Statement of relevance: Our article complies with the Policy Statement for submission of manuscripts to the Genetics Section, as it provides insight into the issue of breeding programs. Here, we have connected previous work in the field to address new questions, focusing on how the mating scheme may affect both genetic gain and inbreeding in aquaculture selection programs, where family sizes are typically large and tank effects are usually present. In fish species, it is possible to consider different mating schemes because fecundity is high and because in vitro fertilization is often possible. A particular problem in aquaculture breeding programs is the impossibility of tagging physically newborn individuals. Given this, a common practice in aquaculture is to rear families in separate tanks until the fish are large enough to be individually tagged. This introduces an environmental effect common to the members of the same family (tank effect) which can lead to a reduction of the response to selection that needs to be considered. We studied here the efficiency of different selection methods in terms of genetic gain and inbreeding and investigated the effect of the mating scheme to optimize breeding programs in aquaculture when tank effects are present. We have shown that assortative mating can substantially enhance the response to selection, particularly when family selection methods are applied and tank effects are present. To our knowledge, the effect of the mating scheme in an aquaculture context has never been addressed before. Our results suggest that assortative mating in the presence of common environmental variance may be considered in selection programs in aquaculture. Our conclusions will help breeders make optimal mating choices.
Genetics and Breeding in Aquaculture
2017
Intensification of aquaculture production has caused environmental deterioration associated with water and sediment eutrophication, resulting in sporadic mass fish kills in some parts of the world. In contrast, eutrophication has been reduced in coastal waters of Japan because of diminished production and improved feeding efficiency of finfish aquaculture and/or mitigation efforts that regulate the allowable amount of terrestrial nitrogen/phosphorus discharge to the sea. Red seabream, Pagrus major, aquaculture production, for instance, peaked in the early 1990s and has been in a decreasing trend since 2000 in Japan. The levels of surface dissolved inorganic nitrogen (DIN) have gradually decreased, while phosphorus levels have been rather constant in Ise Bay since the 1990s, possibly causing a nutrient imbalance for primary production. Surface chlorophyll a levels have been in a decreasing trend since the 1990s, and the occurrence frequency of harmful algal bloom has decreased by 90%...
Aquaculture, 2011
The aim of this paper was to develop and test different methods of applying optimum contribution (OC) to control the rate of inbreeding in various practical breeding schemes for fish, where there is a limitation on the number of full-sib families that can be managed. A simulation study using an infinitesimal genetic model was used to compare the performance of four different ways of implementing OC together with a method commonly used today for controlling inbreeding in fish populations. Breeding programs of different sizes were studied, with the number of families ranging from 40 to 200, and the number of offspring per family ranging from 8 to 200. Heritabilities of 0.1, 0.25 and 0.5 were assumed, and the rate of inbreeding per generation (ΔF) was restricted to 0.005. Average genetic gain (ΔG) for generations 5-15 was used to compare the different schemes. The genetic gain obtained with OC methods were up to 13% higher than for the method commonly used today. The results show although conventional methods of inbreeding control may work in many situations, OC procedures are beneficial and practically possible to implement. Therefore it is concluded that OC procedures should be implemented in aquaculture breeding programs.