A review on recent techniques for elimination of fish fertilized egg adhesiveness

Kalvani Neitali, Bita; Kalbassi, Mohammad Reza; Mojazi Amiri, Bagher; Noori, Ahmad

Volume 2, Issue 2 (Autumn 2012) J. Aqua. Eco 2012, 2(2): 18-1 | Back to browse issues page

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Kalvani Neitali B, Kalbassi M R, Mojazi Amiri B, Noori A. A review on recent techniques for elimination of fish fertilized egg adhesiveness. J. Aqua. Eco 2012; 2 (2) :18-1
URL: http://jae.hormozgan.ac.ir/article-1-118-en.html

A review on recent techniques for elimination of fish fertilized egg adhesiveness

Bita Kalvani Neitali ^*

, Mohammad Reza Kalbassi

, Bagher Mojazi Amiri

, Ahmad Noori

Abstract: (7283 Views)

The eggs of many fresh water fishes become sticky after activation and contact with water. The stickiness property is caused by presence of glycoprotein molecules in outer layer of eggs. In sturgeons the fourth layer of egg (jelly coat) leaks after contacting with water. In teleosts outer zona-radiate is responsible for stickiness. Egg stickiness is important in natural reproduction, whereas eggs can attach to substrate, so brooders can locate the eggs in the best place with the most suitable environmental factors. Also the eggs can be protected by brooders that it strongly raises survival rate. But stickiness is undesirable in hatcheries clumping of sticky eggs results in mortality caused by anoxia and fungal growth. One of the phases in culture of many fresh water fishes, therefore, is to eliminate the egg adhesiveness before incubation. The methods applied for elimination the adhesiveness can be divided into 3 groups: Physical, chemical and enzymatic methods. Physical methods consist of friction the eggs gently with substances such as clay, talc powder and starch. The negative points are lower of hatching rate and time consuming of the process. The most common chemical methods are use of carbamid, tannic acid, milk powder and sodium sulfite (Na2SO3). In enzymatic methods, protease enzymes are administered to eliminate the egg adhesiveness, as the nature of the sticky layer is glycoprotein. Higher hatching rate and quick application are advantageous of this method. Hatching or embryo surviving rate, required time and the expenditure should be noticed for election the best method.

Keywords: Egg stickiness, Elimination of egg adhesiveness, Jelly Coat, Glycoprotein

Full-Text [PDF 840 kb] (6766 Downloads)

Type of Study: Research | Subject: Special
Published: 2015/02/8