2
RUDN University Biologist: salted water saves fish from stress when transporting

RUDN University Biologist: salted water saves fish from stress when transporting

RUDN University biologist with colleagues from Brazil and Iran found how to alleviate the stress of fish during transportation. It turned out that this can be achieved with salted water.

Stress during forced relocation is experienced not only by people, but also by fish in aquaculture. Due to stress, the internal balance in the body of fish is disturbed — how the composition of blood and enzymes changes along the chain, muscle tone increases, behavior changes. Ultimately, this leads to a decrease in health indicators and even death. A RUDN University biologist with colleagues from Brazil and Iran proposed a simple way to alleviate stress during transportation in Nile tilapia, one of the most common species in fisheries. To do this, one just need to salt the water a little.

“Fish is an important product that is present in the diet of many people. It is important to deliver the fish fresh. One of the ways is the delivery of live individuals to stores. However, transportation is a stressful event that negatively affects fish physiology. Stressful events increase cortisol levels, which increase the energy needed to cope with stress. Higher energy costs cause an increase in the gill ventilation rate, which leads to osmotic and ionic imbalance,” Morteza Yousefi, Associate Professor of the Department of Veterinary Medicine, RUDN University.

In itself, the idea of adding salt to water during transport to alleviate stress is not new. However, for the Nile tilapia, the possibility of such a practice has not yet been studied. RUDN University Biologists studied 84 individuals of the Nile tilapia grown on an Iranian fish farm. The fish were divided into three groups and placed in a medium with different concentrations of salt — 2 or 4 grams per liter — and completely fresh water. For three hours, the fish were transported by truck, after which their performance was examined.

The main indicator of stress biologists cortisol levels were measured. Salt supplementation at a concentration of 2 and 4 grams per liter lowered cortisol levels. Fish in fresh water after transportation increased cortisol from 30 to 80 nanograms per milliliter, and fish in salt water — only 60-65 depending on the salt concentration. After recovery, all fish had cortisol back to around 40 nanograms. Also, fish transported in salted water had improved indicators of liver condition, oxidative stress and mineral composition. According to the sum of indicators, the best medium was water with 4 grams of salt per liter.

“Adding salt to the water has a positive effect on the transport of Nile tilapia. In fish in salt water, the degree of stress is reduced, the liver is less damaged, oxidative stress is less pronounced, and hydromineral balance is better maintained. A concentration of 4 grams per liter of salt is useful for transporting Nile tilapia,” Morteza Yousefi, Associate Professor of the Department of Veterinary Medicine at RUDN University.

The results are published in Aquaculture Reports.

Scientific Conferences View all
16 Oct
The collection consists of two volumes and includes biographical information about Russian demographers and their scientific research. The first volume is devoted to the research of the Pre-Revolutionary period, the second to the works of the Soviet era and the present.
65
Main Publications View all
15 Nov 2017
RUDN University scientists publish results of their scientific researches in highly-recognized in whole world and indexed in international databases journals (Web of Science, Scopus ect.). That, of course, corresponds to the high status of the University and its international recognition. Publications of June-September 2017 ( In Journals of categories Q1-Q3)
1850
Similar newsletter View all
16 Oct
Green Diplomacy Center opened in RUDN

A Center for Green Diplomacy was created based on the RUDN Institute of Environmental Engineering. Among the goals is the integration of the results of scientific and practical activities into the development of international relations in the environmental sphere. The center's specialists will also accompany the corporate sector in solving various environmental problems.

76
19 Apr
A huge pizza and a jug of water, why should 5G networks be sliced? The winners of RUDN science competition explain

RUDN summarized the results of the scientific competition "Project Start: work of the science club ". Students of the Faculty of Physics, Mathematics and Natural Sciences have created a project for a managed queuing system using a neural network to redistribute resources between 5G segments. How to increase flexibility, make the network fast and inexpensive and reach more users — tell Gebrial Ibram Esam Zekri ("Fundamental Computer Science and Information Technology", Master's degree, II course) and Ksenia Leontieva ("Applied Mathematics and Computer Science", Master's degree, I course).

156
19 Apr
Lyricists and physicists are now on equal terms: the first humanitarian laboratory opened in RUDN

What is your first association with the word “laboratory”? Flasks and beakers? Microscopes and centrifuges? Yes, many of us would answer the same way.

201
Similar newsletter View all