Perception of light intensity by Haliotis discus discus based on locomotor activity patterns

ABSTRACT:   An apparatus to measure the locomotor activity of aquatic benthic organisms at variable low light levels was developed and the diurnal behavioral pattern of the abalone Haliotis discus discus was measured at various low light intensities. During the experiment, abalone were exposed to 12 h light–dark cycles of complete darkness, 0 µmol/m²/s throughout the 12 h dark cycle and, during periods I (days 1–8) and III (days 19–26), the 12 h light cycles were set at 10 µmol/m²/s. During period II (days 10–17), abalone were exposed to a light level during the 12 h light cycles of 1 × 10⁻⁵, 1 × 10⁻⁶, 1 × 10⁻⁷ or 1 × 10⁻⁸ µmol/m²/s and the changes in locomotor activity assessed. At daytime levels of 1 × 10⁻⁵ µmol/m²/s, typical behavioral patterns were observed of high locomotory activity during the night-time cycle. However, at lower light intensities, the distinction between day and night activity patterns became less clear and, at intensities lower than 1 × 10⁻⁷ µmol/m²/s, the difference between activity during the light and dark cycles became negligible. Based on this, we conclude that the threshold of light level perception in relation to locomotor activity is approximately 1 × 10⁻⁷ µmol/m²/s. The significance of these results in relation to the entrainment of behavior in abalone is discussed.     

羊鲍精巢显微结构的研究

[目的]为羊鲍的人工繁殖提供理论基础。[方法]应用光镜技术研究羊鲍精巢的显微结构。[结果]羊鲍精巢由外膜及其内的大量生殖小管组成;外膜将生殖腺和肝胰腺分开,其组织结构由外至内依次为单层立方上皮、平滑肌纤维和结缔组织;生殖小管在生殖腺内部纵横交错,大量分枝,将生殖腺分隔成许多小腔,生殖小管内生殖细胞发育呈现区域化特征,成熟度越高的生殖细胞越靠近生殖小管腔的中央,反之则靠近生殖小管壁分布。[结论]羊鲍精巢中生殖细胞的发生及其性腺发育与皱纹盘鲍相类似。     

九孔鲍鱼病毒病的防治试验

在福建东山个发病的鲍鱼养殖场进行了对比试验。该种病毒病可通过隔离,使用沙滤水,用鲍毒清药浴或将药拌入产而得到治疗并控制其蔓延。对照池的鲍鱼未采取防治措施短时间内全部死亡。     

Octopus as predators of abalone on a sea ranch

This study examined the occurrence of octopus across an abalone, Haliotis laevigata, Donovan, sea ranch in south‐western Australia, to understand how octopus may be impacting abalone production. Commercial divers removed 654 octopus and 17,666 empty abalone shells during regular, 2 to 4‐weekly surveys over 27 months. A negative binomial generalised linear model estimated a 78% increase in empty shells per artificial abalone habitat per day, when octopuses were present, after adjusting for location and season. Of the 408 shells examined for evidence of predation, 19% had a small, slightly ovoid hole consistent with those made by octopus. The mean (± 1 SE) length of shells with boreholes (70.3 ± 2.2 mm) was significantly longer than those without (59.8 ± 0.5 mm), and boreholes were concentrated over the adductor, respiratory organs and heart. This study provides important insights into the adaptable feeding regimes of octopus and their potential to impose strong top‐down controls on sea ranching operations.     

Substitution effect of Undaria pinnatifida with citrus (Citrus unshiu,Marcovitch) peel by‐product in feed on the growth,body composition and air exposure stressor of juvenile abalone (Haliotis discus,Reeve 1846)

Substitution effect of Undaria pinnatifida with citrus peel by‐product (CPB) on growth, body composition and air exposure stressor of abalone was determined. A total of 1,080 abalone were distributed into 18 net cages. Five formulated diets were prepared in triplicate. The CPB0 diet contained 200 g/kg U. pinnatifida. The 250, 500, 750 and 1,000 g/kg U. pinnatifida were substituted with the equal amount of CPB, referred to as the CPB250, CPB500, CPB750 and CPB1000 diets, respectively. Finally, dry U. pinnatifida was prepared. Abalone were fed for 16 weeks and then subjected to air exposure stressor for 24 hr. The cumulative mortality of abalone was monitored for the following 4 days after 24‐hr air exposure. Survival, weight gain and specific growth rate (SGR) of abalone fed all formulated diets were greater than those of abalone fed the U. pinnatifida. The greatest weight gain and SGR were achieved in abalone fed the CPB500 diet. The chemical composition of the soft body of abalone was not affected by the experimental diets. Higher cumulative mortality was observed in abalone fed the CPB0 and dry U. pinnatifida at 16 hr after 24‐hr air exposure compared to abalone fed all other diets. In conclusion, U. pinnatifida could be completely substituted with CPB in abalone feed.     

Influences of dietary antimicrobial peptide APSH‐07 on the growth performance,immune response and vibriosis resistance of abalone Haliotis discus hannai Ino

A 115‐day feeding trial and subsequently a 10‐day challenge test with Vibrio parahaemolyticus were conducted to investigate the effects of dietary antimicrobial peptide APSH‐07 on growth performance, immune response, antioxidative status and vibriosis resistance of abalone Haliotis discus hannai (initial body weight: 2.06 ± 0.01 g; initial shell length: 25.42 ± 0.18 mm). Four artificial diets were designed with 0 (artificial diet control), 7.5, 15.0 and 22.5 mg/kg of APSH‐07, respectively. The brown alga Laminaria japonica was used as the live food control. Results showed that the specific growth rates of abalone in the groups with 7.5 and 15.0 mg/kg dietary APSH‐07 were significantly higher than those in the controls (p < .05). The total haemocyte counts and respiratory burst activity in haemolymph of abalone in the group with 7.5 mg/kg of dietary APSH‐07 were significantly higher than those in the groups with 0 and 22.5 mg/kg of dietary APSH‐07 (p < .05). The gene expression levels of Mn‐superoxide dismutase and thioredoxin peroxidase 2, and the activities of glutathione peroxidase in the group with 7.5 mg/kg of dietary APSH‐07 were significantly higher than those in the other groups (p < .05). Cumulative mortality of abalone after the challenge test was significantly decreased in the group with 7.5 mg/kg of dietary APSH‐07 supplementation. Supplementation of 22.5 mg/kg dietary APSH‐07 significantly increased the cumulative mortality. In conclusion, 7.5 mg/kg of dietary APSH‐07 supplementation had the better growth performance, higher antioxidation, immune and disease resistance capacity of abalone. Excessive supplementation of dietary antimicrobial peptide APSH‐07 (22.5 mg/kg) had significantly negative effects. Further studies are needed to determine the optimal level of dietary APSH‐07 supplementation for abalone.     

“东优1号”杂色鲍及其亲本群体的形态特征和养殖性能比较

以杂交种东优1号杂色鲍及其亲本群体为研究对象,对三者的外形特征和养殖性能进行了比较。结果表明,在壳形和密度相关的参数中,壳宽/壳长指标差异最为显著,日本群体的壳宽/壳长指标显著地大于台湾群体(P<0.05),而东优1号的值则介于双亲群体之间。采用海区延绳式吊养和陆地工厂化养殖两种养成模式,分别在福建、广东和海南对东优1号杂色鲍及其亲本群体进行为期一年的养殖对比试验。结果表明,杂色鲍台湾群体受养成期暴发性死亡症的严重影响,存活率极低;日本群体虽然具有较好的抗病能力,但生长速度却显著慢于东优1号和台湾群体;东优1号杂色鲍的生长速度和存活率在3个实验点都表现出较为显著的优势。研究结果表明东优1号杂色鲍是适合在亚热带和热带地区进行养殖的优良鲍新品种。     

饲料中脂肪含量对七彩神仙鱼幼鱼生长和消化的影响

在水温29.0±1.0℃下,将140日龄、体质量8～10g的七彩神仙鱼(Symphysodon aequifasciata)幼鱼放入室内54cm×40cm×28era的水箱中,投喂以鱼粉和豆粕为蛋白源(粗蛋白45.0%)、以豆油为脂肪源配制的5种脂肪水平(10.21%、12.02%、17.17%、21.0%,和22.14%)的饲料.90d的饲养表明,七彩神仙幼鱼的成活率变化在96.67%～100.0%之间,各组间差异不显著(P>0.05).随饲料中脂肪含量的增加,鱼的特定生长率(SGR)、蛋白质效率(PER)和增重率均先增加而后降低;摄食含12.02%脂肪饲料的鱼SGR、PER和增重率极显著地高于摄食含10.22%和22.14%脂肪饲料的鱼(P<0.001),而当鱼摄食含17.17%和21.05%脂肪的饲料时,SGR、PER和增重率与摄食含12.02%脂肪饲料的鱼差异不显著(P>0.05).当饲料中脂肪含量为12.02%时,鱼对饲料中蛋白质的消化率最高;摄食含脂肪为10.22%、12.02%和17.17%的饲料时,对饲料蛋白的消化率差异不显著(P>0.05).实验表明,七彩神仙鱼幼鱼饲料中适宜脂肪含量在12.02%～17.17%之间.     

Growth performance of weaning red abalone (Haliotis rufescens) fed with Macrocystis pyrifera plantlets and Porphyra columbina compared with a formulated diet

A feeding experiment was carried out to evaluate two natural diets versus a formulated feed on the performance of weaning red abalone Haliotis rufescens . Four treatment diets were then investigated: a formulated diet; plantlets from culture Macrocystis pyrifera, Porphyra columbina from natural beds; and a mixed diet consisting of a blend of fresh P. columbina together with the formulated diet. This study was performed in a shallow aquaculture system with a horizontal water flow. After 90 days, significant differences were observed between treatments. The highest growth was obtained with Porphyra (3.3 mm month⁻¹), followed by the mixed diet (2.6 mm month⁻¹), then Macrocystis (2.1 mm month⁻¹) and lastly the formulated diet (1.4 mm month⁻¹). Moreover, after the diets were tested for stability and remnant nutrients after a 12-h water immersion, a positive trend appeared to be related to the protein/energy (P:E). It is concluded that fronds of P. columbina resulted in the best diet for weaning H. rufescens under horizontal water flow systems, even if apparently the water stability of the formulated diet had a negative impact on abalone performance, particularly due to a poor nutrient retention capacity. Therefore, formulated diets should be improved before being recommended for weaning red abalone.     

九孔鲍褐藻酸酶降解褐藻胶的反应条件与酶解产物的分析

以九孔鲍(Haliotis diversicoloeaquatilis)为原料制备一定纯度的褐藻酸酶,并对影响其降解褐藻胶的条件和产物的性质进行分析。该酶的最适温度和pH分别为45℃和7.0;与磷酸盐缓冲液相比,其在Tris-HCl缓冲液中与底物的亲和力相对较高。动力学曲线表明酶解反应主要发生在1 h之内,在2 h之内达到平衡,酶的剂量和底物的浓度对该平衡起到一定的影响作用。反应2 h之后,添加同数量的酶或者底物发现,产物的反馈抑制只是反应达到平衡的一个影响因素,而酶的变性失活也起到了重要的作用。金属离子对酶的活性具有明显的影响,Co2 、Mg2 对酶的活性具有较强的促进作用,而Cu2 、Ag 和Zn2 则具有较强的抑制作用。产物特性黏度的变化主要是在1 h内,2 h后基本不再改变。1HNMR图谱分析发现随着聚甘露糖片段,特别是M-M二聚体的降解,MG二聚体、GGM和MGM三聚体的量相应增多,表明该酶属于甘露糖裂解酶(EC 4.2.2.3)。