Abstract: Varied doses of T-2 toxin (T-2), namely 0.0 (control), 0.5, 1.2, 2.4, 4.8, 12.2 mg/kg, were orally administered to the white shrimp Litopenaeus vannamei for 20 consecutive days. The quality characteristics and autolysis of shrimp muscle were investigated by sensory evaluation, physicochemical analysis and microscopic observation. The results indicated that T-2 exposure significantly affect the color of shrimp muscle. T-2 exposure at low dose could result in a significant increase in hardness and chewiness (P < 0.05), but a significant decrease in hardness, elasticity, cohesiveness, glueyness and chewiness at high dose (P < 0.05). The cooking loss of shrimp muscle first rose and then decrease. Microscopic examination revealed loosening and fragmentation of muscle fibers and wider gaps between muscle fibers, suggesting a decline of shrimp muscle quality. Increasing T-2 exposure resulted in a decrease in amino nitrogen content and an increase in soluble solid content. Soluble protein in shrimp muscle hydrolysate increased first and then decreased (P < 0.05). Myofibril length showed a significant decline with the increase in T-2 (P < 0.05). Electron microscopy confirmed fracture and dissolution of myofibrils, suggesting increased autolysis.

Key words: T-2 toxin, Litopenaeus vannamei, muscle, quality characteristics, autolysis