Efficacy of Alfalfa Saponins on Promoting Pigmentation by Astaxanthin in Blood Parrot Fish (Vieja synspila♀× Amphilophus citrinellus♂)

Abstract

This study was conducted to evaluate the effect of alfalfa saponins on pigmentation induced by astaxanthin in 540 blood parrot fish (Vieja synspila ♀ × Amphilophus citrinellus ♂). The fish were divided into six treatment groups: basal diet; a diet supplemented with 3‰ astaxanthin; three diets with 3‰ astaxanthin plus 3‰, 6‰ or 12‰ alfalfa saponins respectively; and a diet supplemented with 4‰ alfalfa saponins alone. The fish were maintained in three aquaria per treatment. At 20, 40, 60, and 80 days, 6 blood parrot fish per aquarium were sampled. At the end of the experiment, the carotenoid content of scales, skin, and caudal fin in groups supplied with 3‰ astaxanthin plus alfalfa saponins were significantly higher than the control. The redness values, a*, of the body and caudal fins in these groups increased significantly. Conversely, the cholesterol and triglyceride content decreased significantly. Non-esterified fatty acid content and lysozyme activity were significantly higher in the three groups fed supplemented astaxanthin diets with the addition of alfalfa saponins, than the group fed a diet supplemented with 3‰ astaxanthin alone (P<0.05). The results show that the addition of alfalfa saponins to diets supplemented with astaxanthin, improves astaxanthin absorption and utilization.