Relative performance of two Nile tilapia (Oreochromis niloticus Linnaeus) strains in Egypt: The Abbassa selection line and the Kafr El Sheikh commercial strain

The Abbassa selection line (developed by selective breeding) and the Kafr El Sheikh commercial strain (widely used in Egypt), both Oreochromis niloticus, were compared at two stocking densities (two and four fish m-2). Harvest weight, length, depth, width and head length were recorded. The Abbassa line showed a superior harvest weight (28 per cent) over the Kafr El Sheikh strain. Males were heavier than females, but the between-sex difference was greater in the commercial than in the Abbassa line (39 and 31 per cent respectively).

Performance of the Genetically Improved Farmed Tilapia (GIFT) strain over ten generations of selection in Malaysia

A selection programme using Best Linear Unbiased Prediction (BLUP) method for the estimation of genetic merit was implemented by the Department of Fisheries Malaysia (DOF) in collaboration with the WorldFish Centre. This collaborative programme provided opportunities for further improvement of the GIFT strain in Malaysia. The overall aim of the present study was to evaluate the performance of GIFT strain during the long-term selection programme in Malaysia.

Indirect genetic effects and inbreeding: Consequences of BLUP selection for socially affected traits on rate of inbreeding

Social interactions often occur among living organisms, including aquatic animals. There is empirical evidence showing that social interactions may genetically affect phenotypes of individuals and their group mates. In this context, the heritable effect of an individual on the phenotype of another individual is known as an Indirect Genetic Effect (IGE). Selection for socially affected traits may increase response to artificial selection, but also affect rate of inbreeding.

Genomics in marine monitoring: New opportunities for assessing marine health status

This viewpoint paper explores the potential of genomics technology to provide accurate, rapid, and cost efficient observations of the marine environment. The use of such approaches in next generation marine monitoring programs will help achieve the goals of marine legislation implemented world-wide. Genomic methods can yield faster results from monitoring, easier and more reliable taxonomic identification, as well as quicker and better assessment of the environmental status of marine waters.

Genetic variance for uniformity of harvest weight in Nile tilapia (Oreochromis niloticus)

Competition for resources is common in aquaculture, which inflates the variability of fish body weight. Selective breeding is one of the effective approaches that may enable a reduction of size variability (or increase in uniformity) for body weight by genetic means. Competition for resources is common in aquaculture, which inflates the variability of fish body weight. Selective breeding is one of the effective approaches that may enable a reduction of size variability (or increase in uniformity) for body weight by genetic means.

Genetic improvement of farmed tilapias: Genetic parameters for body weight at harvest in Nile tilapia (Oreochromis niloticus) during five generations of testing in multiple environments

The main objective of this paper was to report more reliable estimates of the genetic variation and the genotype by test environment interaction for harvest body weight in the GIFT population in the Philippines than could be obtained from the base population by using the data from the five generations following the base population and that covers a wider span of test environments than the later experiments referred to above. Included are also estimates of the genotype by sex interactions for body weight.

Genetic and non-genetic indirect effects for harvest weight in the GIFT strain of Nile tilapia (Oreochromis niloticus)

The main objective of this study was to quantify the heritable variation for growth rate of GIFT, and the contribution of IGEs to this heritable variation. Here we describe the experiment conducted for this purpose, and present estimated parameters of genetic and non-genetic indirect effects on growth rate in the GIFT strain.

Donor-oyster derived heritability estimates and the effect of genotype X environment interaction on the production of pearl quality traits in the silver-lip pearl oyster, Pinctada maxima

The aim of this study was to estimate donor-oyster derived heritability and genetic correlations for pearl quality traits in the silver-lipped pearl oyster, P. maxima; namely pearl size, colour, lustre, shape and complexion. As future breeding programs for pearls are likely to involve oysters that will be reared in geographically disparate locations we also evaluated the potential impact environment G × E interactions may have on the realization of genetic gains for pearl quality traits.

Differences in sexual size dimorphism among farmed tilapia species and strains undergoing genetic improvement for body weight

Many tilapia (Oreochromis spp.) farmers produce all-male populations because of the superior growth rate of males compared to females. To investigate differences in body weight at harvest of males and females among different tilapia strains, we analyzed data from 62,787 individuals collected from pedigreed breeding programs of O. niloticus (GIFT from Malaysia, the Abbassa line from Egypt, and the Akosombo line from Ghana), O. shiranus (the Bunda College-Domasi selection line), O.

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.

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