Alcalase enzyme treatment for elimination of egg stickiness in tench, Tinca tinca L.

Enzyme treatment to eliminate egg stickiness in tench was compared with sta ndard methodology in an attempt to increase egg hatching rate under hatcher y conditions. Three minutes after activation, eggs were exposed to an alcal ase enzyme solution for 2 min. The highest hatching rate of 87.1% was found with 10.0 ml 1(-1) enzyme treatment. Batching rates of ca. 85% were record ed at 15.0 and 5.0 ml 1(-1), but hatching rate decreased to 80% at 20.0 ml 1(-1) enzyme. The traditional desticking procedure involving milk/clay trea tment gave a hatching rate of 74.1% and required 1 h. Under fish farm condi tions, the highest hatching rate of 88.1% was also recorded following treat ment of eggs with 10 ml 1(-1) enzyme, while enzyme concentrations of 7.5 an d 5.0 ml 1(-1) gave hatching rates of ca. 83%. Treatment with milk/clay sol ution gave a hatching rate of 30%. ANOVA showed significant differences bet ween enzyme and milk/clay treatments on the hatching rate (P < 0.0001). (C) 2000 Elsevier Science B.V. All rights reserved.