Abstract

Swimming performance is one of the crucial factors determining the lifestyle andsurvival of Penaeid shrimps. This study examined under controlled laboratory conditions, the physiological responses to swimming fatigue of juvenile white-leg shrimp Litopenaeus vannamei (8.85 ± 0.05 cm TL) exposed to different currentvelocities, temperatures and salinities factors which have been correlated with their swimming performance. The swimming endurance of juveniles decreased as current velocity increased from 5.41 to 11.47 cm s^-1 at any of the temperatures and salinities tested. Exercise to fatigue led to severe loss of serum total protein concentration (PC) and serum glucose level (SG) in L. vannamei exposed to different current velocities, temperatures and salinities (P < 0.05). Moreover, decrease of PC and SG in fatigued shrimp varied with current velocity, temperature and salinity. The results showed that the mobilization of protein and glucose in response to swimming fatigue was rapidly diminished and suggest how physiological responses to swimming fatigue of juvenile white-leg shrimp L. vannamei exposed to different current velocity, temperature and salinity may determine their swimming performances.

Key words: Litopenaeus vannamei, swimming fatigue, current velocities, temperatures, salinities.