Effects of defatted Haematococcus pluvialis meal (DHPM) supplementation on the growth performance, and the carotenoid content and composition in the rotifer (Brachionus plicatilis)

A feeding study was conducted to determine the effects of defatted Haematococcus pluvialis meal (DHPM) on the growth performance of rotifers (Brachionus plicatilis). To assess the efficiency of DHPM as a new additive for rotifer enrichment, the effects of DHPM supplementation on carotenoid and astaxanthin concentrations of the rotifers were investigated. The results showed that the addition of DHPM (125 mg l−1) increased the total number of rotifers (TR), the number of egg-bearing rotifers (EBR), and the number of rotifer eggs (RE). The large proportion of total egg-bearing rotifers indicated that DHPM was good for rotifer growth and reproduction. After feeding on DHPM, rotifers had significant increases (P < .05) in carotenoids including astaxanthin. Total carotenoid and astaxanthin concentrations in the treated rotifers increased 4.8 times and 9.0 times respectively as compared with the control group (no DHPM). In addition, the ratios of β-carotene, each astaxanthin isomer (all-trans, 9-cis, 13-cis and 15-cis astaxanthin) and the degradation product astacin, to the total carotenoid content, were calculated for rotifers of the control and treatment groups. The results suggested that the addition of DHPM led to a decrease in the proportions of β-carotene (from 9.34% to 2.51%) and astacin (from 41.83% to 12.44%) of the total carotenoids, but to an increase in the proportion of all-trans astaxanthin (from 40.46% to 77.73%) to the total carotenoid. We propose that the different compositions of carotenoids had effects on the growth performance of rotifers. As a result, it was concluded that the addition of DHPM is beneficial for rotifer growth and enhanced the nutritional quality of the rotifers as first feed for aquaculture.