Abstract

A study was conducted to investigate the accumulation of trehalose in infective third (L₃) stage of Haemonchus contortus induced for hypobiosis by exposure to gradual increase in temperature and decrease in moisture. Trehalose content in stressed L₃, hypobiotic (L₄) and mature H. contortus was estimated by densitometry. It was established that infective (L₃) larvae subjected to moisture stress accumulated significantly (p = 0.037) higher levels of trehalose compared to the unstressed controls. In addition, infection of goats with the stressed L₃ resulted in high proportion of larvae arrested at the fourth (L₄) larval stage as indicated by the number of L₄ recovered from the abomasal sub-mucosal tissue of goats slaughtered 24 days post infection. These hypobiotic larvae (L₄) had significantly (p = 0.0024) higher relative trehalose content than mature H. contortus recovered from the lumen of the abomasa. The high correlation of trehalose content in stressed larvae and hypobiosis suggested that trehalose metabolism could play a role in hypobiosis. It is suggested that further research should be conducted to confirm or refute this link between hypobiosis and trehalose metabolism.

Key words: Hypobiosis, trehalose, stressed, Haemonchus, larvae.