Raising tilapia is easy and inexpensive. It adapts well to fresh or salt water and fattens fast. Unlike most salmoniforms in aquaculture (salmon, trout, perch, bream), for which fishmeal and fish oil constitute an essential part of their diet, tilapia is lower down in the trophic or food chain and feeds on algae, plankton or small animals. In extensive and semi-extensive production systems, tilapia is largely fed on vegetable waste (rice, cotton, etc.).
Thus, with output exceeding 2 million tons each year, tilapia production contributes to sustainable development without damaging marine resources. This is one of the arguments put forward to support research into the complete sequencing of the tilapia genome. In addition, it is one of two species of interest to aquaculture which is being studied more than any other in laboratories.
Sex determination at the service of aquaculture
This model fish belongs to the order percomorphs which includes many French and European species, such as perch, bream and pargo bream. These fish take a long time to reach sexual maturity, which means that their genetic study is not easy. As tilapia has a short generation gap, it can be used as a study model for improving percomorphs. It is also the main group used for studying the phenomena of speciation (birth of a new species).
Of the 10 laboratories involved in the tilapia genome sequencing project, CIRAD and Stirling University of Aquaculture (Great Britain), are particularly interested in the benefits that the project may represent for aquaculture. They are researching genes linked to characteristics of interest, such as growth, rusticity, sex ratio (proportion of males to females), etc.
The tilapia breeders are calling on research for the selection of male tilapias, which grow much faster than the females. The CIRAD research unit Aquaculture and aquatic resource management is developing research programmes to find a real hormone-free alternative for producing single sex male populations. Research into genetics and the use of breeding conditions could provide solutions to the danger of hormones in food, human health and the preservation of biodiversity.
”High water temperature may influence the sex of fingerlings, so we are genetically selecting parents in the hope that the progeny will have this heritable characteristic, “ explains Jean-François Baroiller, a scientist at the research unit Aquaculture and aquatic resource management. Genetic markers for thermal sensitivity are used to optimise this kind of selection and also to study individuals of interest within the natural diversity of tilapias. A similar approach has been set up to develop tilapias resistant to high variations in water salinity in order to meet the demand of numerous producing countries.
The expected development of the first sequences will complete numerous specific genome resources for tilapia that have already been developed by CIRAD. Three PhD students from the research unit Aquaculture and aquatic resource management are working full-time on these issues in collaboration with international research organisations. The sequencing project is already of considerable benefit to the scientific community as well as for world aquaculture.* CIRAD (France)
Helen Burford | alfa
Light green plants save nitrogen without sacrificing photosynthetic efficiency
21.11.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign
Filling intercropping info gap
16.11.2017 | American Society of Agronomy
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences