中国水产科学2017，Vol.24Issue(4)：774-782,9.DOI:10.3724/SP.J.1118.2017.16312
不同品系球等鞭金藻在生长及脂肪酸组成上的种内差异
Intraspecific variability in growth and fatty acid composition among five strains of Isochrysis galbana
摘要
Abstract
Isochrysis galbana is an excellent unicellular bait for the larvae of many aquaculture animals. Thus, screening for I. galbana strains with rapid growth rate and high content of docosahexaenoic acid (DHA) and ei-cosapentaenoic acid (EPA) is very important for the breeding of aquaculture animals. However, most of the I. galbana strains in China have been derived from a common ancestor called I. galbana OA-3011, and different strains of I. galbana have been developed after a long duration of geographical isolation. Whether the traits of these strains have changed or not remains unknown. In order to evaluate the status of the phenotypic traits of dif-ferent geographic isolates for future selective breeding, comparative analysis of five strains of I. galbana (FACHB-861, OA3011-QD, OA3011-LK, OA3011-AY, and OA3011-LZ) with regard to their taxonomy, growth, and fatty acid composition was conducted. Different strains were cultured under identical conditions for six days until they reached a stationary phase. Genomic DNA was extracted for polymerase chain reaction sequencing of the 18S rDNA gene. The OD660 was recorded daily for plotting a growth curve. When the cultures reached statio-nary phase, they were harvested by high-speed centrifugation for biomass determination and fatty acid analysis by using gas chromatography. Phylogenetic analysis of the 18S rDNA gene suggested that FACHB-861 was distantly related with the OA-3011 strains. OA3011-LK, OA3011-AY, and OA3011-LZ had identical 18S rDNA sequences, but the 18S rDNA sequence of OA3011-QD differed from that of the other OA-3011 strains at one position, re-sulting in a single base substitution. The growth curve showed that the five strains reached stationary phase at dif-ferent times. FACHB-861 showed a distinct pattern of growth, unlike the other four OA-3011 strains. The final biomass concentrations were significantly different between I. galbana FACHB-861 and OA-3011 strains as well as among OA3011-LK, OA3011-AY, and OA3011-LZ (P<0.05), whereas the growth rates were not significantly different among the strains (P>0.05). The total fatty acid content of FACHB-861 and OA3011-LZ were signifi-cantly lower than that of OA3011-LK, OA3011-QD, and OA3011-AY (P<0.05). The fatty acid profile of FACHB-861 was remarkably different from that of the OA-3011 strains. However, a conspicuous variation in fatty acid compositions was also observed among OA-3011 strains, indicating a wide and frequent quantitative pheno-typic variation among the strains of I. galbana. These variations resulting from geographic isolation might provide a feasible method for the selective breeding of I. galbana strains. According to the screening criteria such as growth rate or DHA, EPA, and polyunsaturated fatty acid content, our preliminary analysis showed that OA3011-LK, which has the highest growth rate, and OA3011-QD, which contains the highest amount of DHA, are promising candidates for further screening.关键词
球等鞭金藻/品系/生长/脂肪酸/遗传差异Key words
Isochrysis galbana/strain/growth/fatty acid/genetic variation分类
农业科技引用本文复制引用
丛超,胡冬雪,孙春晓,乔洪金,王际英,张利民..不同品系球等鞭金藻在生长及脂肪酸组成上的种内差异[J].中国水产科学,2017,24(4):774-782,9.基金项目
国家自然科学基金项目(31201973) （31201973）
山东省优秀中青年科学家科研奖励基金项目(BS2013HZ018) （BS2013HZ018）
国家海洋生物产业-水生动物营养与饲料研发创新示范平台项目(201601003). （201601003）
