Sexual maturation: Effect on protease activities and carotenoid levels in Atlantic salmon (Salmo salar)

Abstract

Protease activities in the digestive tract and carotenoid levels in flesh, ovaries and plasma were determined in 4 to 4 1/2 year old Atlantic salmon (Salmo salar) during the period from early March until December. The protease activities in the digestive tissue significantly changed during the maturation process. The sexual maturation significantly decreased the level of astaxanthin in the flesh and ovaries, but the total amount in the ovaries still increased. The covariance between astaxanthin in plasma and tryptic-like activities in the digestive tissues were significant, and the level of astaxanthin in plasma was also influenced by time and stage of sexual maturation.