Effect of Different Fertilization and Egg De-adhesion Methods on Hatching and Survival of Clarias gariepinus (Burchell 1822) Fry

Abstract

Abstract:Egg adhesiveness has been a major problem affecting the hatchability of Clarias gariepinus. The removal of egg stickiness will improve aquaculture production through enhanced hatching rates. However, appropriate media for removal of adhesiveness in Catfish eggs is not yet well established. This study therefore, determine the optimum concentration and rinsing time of powdered milk (PM), Urea (UR) and Tannic acid (TA) for removal of adhesiveness of African catfish eggs and their effect on fertility and hatching success. Milt and eggs obtained from African Catfish broodstock of the same lineage were used for induced breeding following standard procedure. Four hundred fertilized eggs each were rinsed in the three different media at varying concentrations and exposure time using dry and wet fertilization methods. Treatment efficacy was assessed by comparing the percentage of non-stick eggs, fertilization, hatching and survival rate in the treatment groups and the control. Data were subjected to multivariate general linear model and Duncan multiple range tests at α 0 . 05 . Under the wet fertilization method eggs exposed to 10 g PM at 20 minutes gave the highest number of free eggs (87.50%) while 6g UR at 5 minutes recorded the lowest (27.09%). In dry method, 14 g PM at 20 minutes recorded the highest number of free eggs (90.00%) whereas, the lowest (47.50%) was recorded in 6g urea at one minute rinsing time. The highest number of hatchlings for PM, UR and TA were 53.26%, 33.24%, and 13.13%, respectively. The survival rate was high in all treatments except in 1.5 g TA. Eggs treated with PM solution performed best in adhesiveness removal and recorded highest percentage fertilization and hatching rate. However, more studies should be conducted to establish the appropriate media for other culture fish species.

Effect of different exposure time of papain on adhesion and some reproductive indices of <i>Clarias gariepinus</i> (Burchell, 1822) eggs under semi-arid environment of Sokoto, north-western, Nigeria

“…The highest percentage (32%) was obtained in treatment 2 exposed to papain for 30 secs and was significantly different (P<0.05) from control, and longer exposure times. This is in line with Kareem et al, (2017) who reported that every rinsing agent has a specific exposure time when they are most effective. The result obtained is also in line with other research that reported significant differences in adhesion between control and the use of rinsing agents.…”

Efecto del desgomado y la temperatura sobre la eclosión de huevos del bagre, Pangasianodon hypophthalmus

“…También se reportaron porcentajes de eclosión superiores al 80% en la lucioperca, Sander lucioperca, al eliminar la capa adherente de los huevos con ácido tánico a una concentración de 0.75 g L -1 y un tiempo de exposición entre uno y dos minutos (10). No obstante, porcentajes de eclosión menores al 5% fueron reportados en bagre africano, Clarias gariepinus, cuando emplearon ácido tánico a la misma concentración utilizada en este trabajo, pero con un tiempo de exposición de 0.5 min (12). Lo que sugiere que para un efecto eficiente del ácido tánico en el desgomado de los huevos de bagre puede ser necesario un mayor tiempo de exposición, como el que se hizo en este trabajo.…”

“…Para la eliminación de la capa adherente de los huevos en aquellas especies de peces que presentan dicha característica, se han empleado diversos métodos, desde tratamientos mecánicos como la agitación de los huevos para separarlos como en la lucioperca americana, Stizostedion vitreum (5), el empleo de productos naturales como arena, arcilla, leche en polvo y jugo de piña, para el desgomado de huevos de tenca, Tinca tinca (6); lucioperca, Sander lucioperca (7) y botete diana, Sphoeroides annulatus (8,9), hasta la aplicación de tratamientos químicos como urea, sulfito de sodio, enzimas proteolíticas y ácido tánico, en el desgomado de huevos de lucioperca, S. lucioperca (10) vaqueta, Labrus bergylta (11), bagre africano, Clarias gariepinus (12), trucha arcoiris, Oncorhynchus mykiss (13), tenca, T. tinca (14), lucioperca, S. lucioperca (15) y esperlano arcoiris, Osmerus mordax (16).…”

The Effect Dose and Soaking Time of Camellia sinensis Solution to the Egg Adhesion and Hatching of Pangasionodon hypophthalmus

“…At high concentration, tannic caused the chorion to harden, thus decreasing the chorionase activity and the development of embryogenesis is disrupted (Kareem et al, 2017). High concentration of tannic acid gave a negative impact on the pikeperch larvae hatching has been reported by Zakes et al (2005).…”