Artificial rearing of Actinopyga lecanora (Holothuroidea: Holothuriida) with spawning induction using relaxin: Lecithotrophic short larval period
Artificial rearing of Actinopyga lecanora (Holothuroidea: Holothuriida) with spawning induction using relaxin: Lecithotrophic short larval period
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DOI：
10.1016/j.aquaculture.2022.739226
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发表时间：
2023-01-16
期刊：
影响因子：
4.5
通讯作者：
Yoshikuni，Michiyasu
中科院分区：
文献类型：
--
作者：
Tanita，Iwao;Sanda，Tetsuya;Yoshikuni，Michiyasu
首次研究了热带海参放线参幼鱼的人工饲养技术。在日本亚热带冲绳八重山群岛采集亲鱼个体，用活检法测定性腺成熟度进行分类。将一种人工合成的松弛素肽注射到成熟尿素的体腔液中。在3 × 10−9 ~ 10 × 10−9mol kg−1体重范围内，14只雌性中有10只、3只雄性中有3只在26-70 min后成功诱导产卵。每只雌虫的产卵数为2.2 ~ 9.5 × 105。卵母细胞的平均直径。诱导产生的海参个体尺寸为324±13 μm，远大于处于浮游营养幼虫期的海参。胚在原肠期孵化，幼虫先蜕变为浮游木耳虫，再蜕变为水螅虫，最后进入底栖五行虫阶段。在26 ~ 28℃条件下，5 ~ 500 L的培养池中饲养幼虫，从受精到沉降时间为4 ~ 8 d，是海参中发育周期最短的品种之一。虽然在大多数饲养批中，幼虫都被提供了细毛毛藻细胞，但后来证实幼虫是卵磷脂营养（非摄食）的，因为：(1)幼虫在没有摄食的情况下成功饲养至定居；(2)叶绿素荧光。荧光显微镜下观察到，格拉氏菌未被纳入幼虫肠道。黑木耳幼虫侧臂突出发育不良，未形成透明球。初始饲养密度在0.4 mL - 1以下，成活率相对较好。用聚碳酸酯波纹板回收沉淀幼虫，波纹板上预先生长有周围硅藻。从孵化到定居后2个月存活率为1.0-1.8%，与其他海参的报告值相当。定居后的幼鱼在定居后的50天内变成橙色，背部有黑色的乳头，随后逐渐变成深绿棕色的背部色素。定居后4个月，幼鱼出现肛齿，颜色与成虫相似。6 - 12月定居幼鱼长势为91.8±1.5 μm day - 1, 170 d长15.11±5.63 mm，冬季12 - 2月为负长势。lecanora具有低成本种子生产的潜力，这有利于发展水产养殖和重新放养。
Artificial rearing techniques of larvae and juveniles of the tropical sea cucumber,Actinopygalecanorawere developed for the first time. Broodstock individuals were collected in Yaeyama Islands, Okinawa, subtropical Japan and sorted by the gonad maturity which was determined by biopsy. An artificially-synthesized relaxin peptide, originated fromHolothuria(Metriatyla)scabra, was injected into the coelomic fluid of matureA. lecanoraat amounts of 3 × 10−9to 10 × 10−9mol kg−1body weight, which successfully induced spawning in 10 of 14 females and 3 of 3 males after 26–70 min. The number of eggs spawned per one female individual ranged 2.2–9.5 × 105. The mean diameter of oocytes ofA. lecanoraindividuals which spawned by the induction was 324 ± 13 μm, much larger than those of sea cucumber species having a planktotrophic larval stage. The embryo hatched during gastrula, and the larva metamorphosed to planktonic auricularia followed by doliolaria and finally settled into the benthic stage as pentactula. Time after fertilization to settlement was 4–8 days when larvae were reared in 5–500 L tanks at 26–28 °C, which is one of the shortest development periods among sea cucumbers. Although larvae were supplied withChaetoceros graciliscells in most rearing batches, the larvae were later confirmed as lecithotrophic (non-feeding) as (1) larvae were successfully reared until settlement without feeding, and (2) chlorophyllafluorescence ofC. graciliswas not incorporated into the larval intestine as observed under fluorescence microscopy. Auricularia larvae showed poor development of lateral arm protrusion and did not form hyaline spheres. Initial rearing densities under 0.4 larva mL−1resulted in relatively good survival. Settling larvae were retrieved using polycarbonate corrugated sheets on which periphytic diatoms had been grown beforehand. Survival from hatching to 2 months after settlement was 1.0–1.8%, comparable with values reported for other sea cucumbers. Postsettled juveniles became orange-colored with black dorsal papillae in 50 days after settlement and subsequently gradually obtained a dark green-brown dorsal pigment. Juveniles having anal teeth and adult-like color pattern appeared from 4 months after settlement. Growth of the settled juveniles was 91.8 ± 1.5 μm day−1from Jun to Dec, reaching 15.11 ± 5.63 mm long in 170 days, while the juveniles negatively grew during winter from Dec to Feb. The lecithotrophic short larval period ofA. lecanorahas potential for low-cost seed production, which is advantageous for development of aquaculture and restocking.