Effects of dietary astaxanthin on population growth of rotifer Brachionus plicatilis and astaxanthin accumulation efficiency
LIU Hui, SUN Na, JIANG Yusheng, XU Xiang, WANG Aolin, ZHANG Naida, ZHANG Bingqian
1.College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China；2.Research and Development Center, Panjin Guanghe Crab Industry Company Limited, Panjin 124200, China
Abstract: In order to explore effects of astaxanthin on population growth of rotifer Brachionusplicatilis and enrichment efficiency, the rotifer was cultured in a 120 L plastic tank at initial inoculation density of 10 ind./mL and fed microalga Nannochlorsis sp.(control group), and the microalga supplemented with astaxanthin at a dose of 0.05, 0.10 and 0.15 mg/L as the treatment groups at water temperature of 23-25 ℃ and salinity of 18 for 7 d.Meanwhile, 12 h astaxanthin enrichment culture experiment was carried out under the same conditions.Results showed that the maximal rotifer density of 134 ind./mL, average daily growth of 17.1 ind./(mL·d), average daily growth rate of 36.6%/d and final growth multiple fold of 13.0 were observed in the rotifer in 0.15 mg/L astaxanthin addition group, significantly higher than those in 0.05 mg/L astaxanthin group and control group(P<0.05).The rotifer had the maximal astaxanthin contents at 4 h in the rotifer in 0.10 mg/L astaxanthin addition group(17.02 μg/mg)and 0.15 mg/L astaxanthin addition group(19.46 μg/mg), and had high enrichment efficiency(3.99 and 4.60 μg/(g·h), respectively), significantly higher than those in the other groups(P<0.05).The enrichment efficiency of astaxanthin in rotifers in the three astaxanthin addition groups was decreased gradually and stabilized when culture time was prolonged.The maximal concentration of ammonia nitrogen in the culture water was found in 0.15 mg/L astaxanthin group(2.40 mg/L), significantly higher than that in 0.05 mg/L astaxanthin group and control group(P<0.05).The changes in nitrite concentration and pH in the culture water were relatively stable in rotifers in each group, without significant difference(P>0.05).The dissolved oxygen content in each group was negatively correlated with rotifer density, significantly lower dissolved oxygen content in 0.15 mg/L astaxanthin group than that in other groups(P<0.05).The findings indicated that supplementation with astaxanthin into Nannochlorsis sp.to feed rotifer Brachionusplicatilis is beneficial to the growth of rotifer population and can effectively enrich astaxanthin under the experimental conditions, 0.10 mg/L astaxanthin being of suitable dose for intensive culture of rotifer for 4 h, and feeding aquatic seedlings based on the comprehensive analysis of enrichment efficiency and cost.
2022, Vol. 37 
