Effect of adhesive coat elimination and temperature on hatching of eggs of striped catfish, Pangasianodon hypophthalmus Español

Objective. This study aimed to assess the effect of tannic acid and protease on the elimination of adhesiveness in fertilized eggs of striped catfish, P. hypophthalmus, to improve the incubation conditions. Materials and methods. Tannic acid at 0.5 g L-1 for 5 min and protease at 5 mL L-1for 8 min were used to eliminate the adhesive coat of fertilized eggs, and a control group was used without chemical addition. Then, the eggs from all treatments were incubated at 26, 28, and 30°C. Results. The eggs treated withprotease did not hatch at any temperature, while in eggs treated with tannic acid and incubated at 26 and 28°C, hatching rates above 60% were observed, where those eggs incubated at 28°C (84.7±1.3%) had the highest hatching rates (p<0.05) among all the treatments. The eggs of the control group had significantly higher hatching percentages (14.2 ± 0.6%) when they were incubated at 28°C than at 26 or 30°C. Conclusions. The results showed a significant interaction between the type of degumming and the incubation temperature, indicating that tannic acid produces the best hatching percentage at 28°C.