Brazilian researchers have developed a new approach to measuring the body composition of living fish, such as PACU (Piaractus mesopotamicus) and the tilapia-do-nilo (Oreochromis niloticus), using the double -energy x -ray absorption technique (DXA). This technology replaces the traditional comparative slaughter method, bringing significant benefits to aquaculture research.
The work involved teams from the Aquaculture Center of Paulista State University (UNESP) in Jaboticabal and the Brazil University of Fernandópolis. In article published in the magazine Aquaculturethe authors argue that the strategy, as well as more accurate and rapidly, reduces the operating costs associated with the analysis of fish body composition.
DXA, widely used in humans to evaluate bone densitometry, was adapted to fish and showed high precision in protein analysis, fat, water, mineral matter and total weight at different stages of animal growth, as well as the possibility of fish measurement thinking also in metabolic weight studies.
The procedure basically consists of anesthetizing the fish, positioning it in the machine, performing scanning (6 to 10 minutes) and, after the procedure, return the animal to the nursery to continue being studied.
DXA application in PACU (Photo: Cleber Mansano)
The DXA technique offers advantages for aquaculture research, the main one being its noninvasive approach. Unlike traditional methods, which slaughter animals throughout the research to measure their body composition, this method allows repeated analysis of the same fish over time. “This enables detailed monitoring of animal growth and development without damaging,” says João Batista Fernandes, a researcher at the UNESP Aquaculture Center and co -author of the article.
Although DXA offers speed and accuracy, the high cost of the equipment, which ranges from $ 50,000 to $ 100,000, can be an obstacle to its wide adoption. To optimize the use at UNESP Jaboticabal the device is shared between different research projects within the university and in collaboration with other institutions, expanding its impact and enabling studies in various areas.
Impacts on research and production
The technique is particularly relevant for nutrition, reproduction and genetic improvement studies. “With DXA, we can evaluate body chemical composition – proteins, fat, minerals and water – without sacrificing animals. This is essential for nutrition or long -term work, such as genetic selection, ”says Fernandes. This approach is already adopted in studies with pigs and birds.
Initially applied in Pacu and Nile Tilapia, the strategy will also be expanded to other commercial species, such as Tambaqui (Macropomum colossoma), pirarucu (ARAPAIMA GIGAS) and matrinxan (Brycon cephalus).
“DXA is an important approach to investigating factors that influence body composition and, for example, support the definition of nutritional management strategies. It is a valuable tool for evaluating freshwater or salty fish, or endangered species, as there is no need to slaughter them, ”add the authors.
The study was supported by FAPESP through the project “Modeling of production and nutritional requirements of birds and fish ”And the postdoctoral scholarship of Cleber Fernando Menegasso Mansano, first author of the study.
*With information from the UNESP Jaboticabal Graduate Program in Aquaculture Program.
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This content was originally published in noninvasive technique measures fish body composition with lower cost on the CNN Brazil site.
Source: CNN Brasil
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