First Report on Successful Triploidy Induction in Clarias gariepinus (Burchell, 1822) Using Electroporation

Abstract

This study investigated the use of electric-shock in inducing triploidy in African catfish Clarias gariepinus. To achieve this, three voltages (9, 12, 21 V) were applied for different durations (3, 5, 10 min). the shock was initiated approximately three minutes after fertilization followed by incubation in ambient temperature. After incubation, hatchability and survival rates were determined while ploidy status of the treatment fishes was confirmed in one-month-old fingerlings using the exclusive triploid range of the erythrocyte major axis previously reported for the same species (11.9-14.9 μm) and by cytogenetic analysis of the chromosome. The results showed triploidy were achieved in 10 to 85% of the treatment groups. A consistent trend of decrease in hatchability and an increase in triploidy rate was observed with increased electroporation voltages and shock durations. The mean erythrocyte major axis length of triploid progenies (3n = 84) was observed to be between 11.3-14.6 μm and was higher than the range of 7.0-10.5 μm recorded for diploid progenies (2n = 56). It was concluded that electric shock can be used to induce triploidy in African catfish C. gariepinus.

Genetic Variation between Triploid and Diploid Clarias gariepinus (Burchell, 1822) Using RAPD Markers

“…Upon hatching, the fry was maintained for three months (feeding initially with Artemia nauplii ad libitum and later with catfish starter diet). At this age, the ploidy status of the juveniles was confirmed following the triploid erythrocyte exclusive range (i.e., erythrocyte main axis of 11.9–14.9 μm) used by Normala et al, [ 6 , 7 ], Hassan et al, [ 5 ] and Okomoda et al, [ 2 ].…”

“…Triploidy induction during breeding is one of the genetic manipulation methods used to alter the chromosome number of many cultured organisms in an attempt to improve performance characteristics [ 1 ]. Triploid animals are produced by inhibiting the release of the second polar body through the application of physical or chemical shock shortly after fertilization [ 2 ]. The consequences of triploidy induction in aquaculture are numerous and range from better growth performance to the production of sterile fish [ 3 ].…”

Advantages, Factors, Obstacles, Potential Solutions, and Recent Advances of Fish Germ Cell Transplantation for Aquaculture—A Practical Review

“…Triploids can be generated by blocking the extrusion of the second polar body or breeding diploids with tetraploids which were produced by blocking the first mitosis [ 105 , 106 ]. Various techniques such as temperature shock (heat/cold), high pressure, chemicals, and electroporation have been developed to produce triploid fish in multiple species [ 107 , 108 , 109 ]. Although some triploid fish can produce a small amount of milt or eggs, their gametes may not have fertility, or their offspring cannot develop normally [ 110 , 111 ].…”

Status of genetic and genomic approaches for delineating biological information and improving aquaculture production of farmed rohu, Labeo rohita (Ham, 1822)

“…Nonetheless, there are prospective benefits of chromosome manipulation in sex control, population control, selective breeding and conservation. Recently, sterile triploid fish have been produced in mass scale for economic trait improvement in aquaculture (Benfey, 2016; Okomoda et al, 2020).…”