Enrichment of Artemia metanauplii in phospholipids and essential fatty acids as a diet for common octopus (Octopus vulgaris) paralarvae

Highly unsaturated fatty acids (HUFA), like the eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and polar lipids (essentially phospholipids, PL) have been identified as essential nutrients for common octopus (Octopus vulgaris) paralarvae. However, they are not available in sufficient amounts in live preys as Artemia, making necessary a supplementation of these nutrients previous use. A commercial emulsion, soya liposomes, and marine and soya lecithins were used to supply HUFA and PL to Artemia metanauplii, those being regarded as suitable size preys for octopus paralarvae. Our results prove that a simultaneous enrichment in HUFA and PL is possible using enrichment diets combining HUFA‐ and PL‐rich products in short‐term (4 h) incubations. Particularly interesting was the enrichment efficiency shown by the marine lecithin, which enabled the enhancement of the PL fraction of Artemia metanauplii and, importantly, also their HUFA with a remarkable 13% DHA of total fatty acids. Marine lecithin arises as a novel enrichment diet for Artemia and more effective than some commercial products currently used in hatcheries worldwide.     

浙江南麂岛真蛸网箱和水泥池养殖试验

2005年11月至2006年1月,分别在传统网箱和室内水泥池投放真蛸(Octopus vulgaris)野生苗种22062头,进行了养殖初步试验。主要结果为,55口传统网箱共放养10912头,平均体重233.6g,经过40d养殖,平均体重达660.9g,生长速度快,日增重率高达2.389%,养殖成活率62.8%,饵料系数为8.08。18口室内水泥池共放养11150头,平均体重220.5g,第一阶段经过33d养殖,平均体重达364.5g,生长速度不如传统网箱,日增重率1.402%,养殖成活率70.9%,饵料系数为6.04;第二阶段进入越冬期,生长更慢,经过53d养殖,平均体重达489.5g,日增重率只有0.552%,死亡较严重,养殖成活率仅44.3%,饵料系数为8.97。传统网箱养殖经济效益高于室内水泥池,投入产出比前者为11.210,后者为11.105。此外,还对影响真蛸生长和成活的各种因素、互残和自残行为等方面内容进行了分析探讨。     

Growth and mortality of common octopus Octopus vulgaris reared at different stocking densities in Mediterranean offshore cages

Four ongrowing cycles of common octopus ( Octopus vulgaris ), each with two stocking densities, were carried out in an offshore area in order to evaluate the effect of the following variables on growth ( G , % body weight day⁻¹) and mortality ( M , % day⁻¹): weight ( W , 0.5–3.0 kg), temperature ( T , 14–26 °C), stocking density (SD, 6–46 kg m⁻³), size dispersion, expressed as coefficient of variation (CV, 13–42%) and significant wave height (SWH: 0.4–1.2 m). The assays were performed in an 8 m³ stainless-steel floating cage divided into two compartments of 4 m³ each. For the range of temperatures considered (14–26 °C), G depended significantly on T and SWH, with maximum G values being obtained at 18.5 °C and with an important negative effect of SWH. M depended significantly on T, W and CV, mortality being minimal at 18 °C. The two other variables had an antagonistic effect, mortality increasing with greater size dispersion – suggesting that animals should be graded throughout the process – although the effect diminished as the sizes increased. The results point towards two alternatives for the commercial ongrowing of octopus under the particular conditions of the present study: (A) two ongrowing cycles of 3.5 months to reach a final weight of 2.5 kg or (B) one 5-month cycle to reach a final weight of 3.5 kg.     

Investigation of the potential effect of diet,body mass and maturity on growth and feed performance of common octopus Octopus vulgaris: an information theory approach

The potential effect of body mass (m), maturity stage (ms), food type (ft), food protein (p) and lipid (li) content, and food protein‐to‐energy ratio, P/E (pe) on Specific Growth Rate (SGR, % day⁻¹), Absolute Feeding Rate (AFR, g day⁻¹), Feed Efficiency (FE, %), Assimilation Efficiency (AE, %), and Protein Retention Efficiency (PRE, %) in the common octopus was investigated. Six food types were provided ad libitum: shrimp, squid, hake, mussel, sardine and artificial one (gels made of hydrated squid flour agglutinated with sodium alginate). Estimated SGRs, AFRs, FEs, AEs and PREs were modelled with General Linear Models based on an information theory approach, using m, ms, ft, p, li and pe as potential predictor variables. SGR decreased when m increased; octopuses fed on shrimps showed the highest SGRs and the ones fed on mussels showed the lowest SGRs. AFR increased with m. Maximum and minimum FEs were observed, when food provided was shrimps and mussels, respectively. Maximum PRE was performed by octopuses fed on shrimps or sardines and minimum PRE by octopuses fed on mussels. Octopuses fed on artificial diet reached satisfactory levels of SGR (0.50% day⁻¹) and FE (12.3%).     

Identification of tropomyosin as a major allergen in the octopus Octopus vulgaris and elucidation of its IgE-binding epitopes

ABSTRACT: The major allergen (named Oct v 1) in the muscle of the octopus Octopus vulgaris was purified by gel filtration on Sephacryl S-300, anion-exchange fast protein liquid chromatography on Mono Q and reverse-phase high-pressure liquid chromatography on TSKgel Octadecyl-4PW. In addition to the molecular mass, amino acid composition and cross-reactivity with Tur c 1 (turban shell Turbo cornutus allergen), the determined partial amino acid sequence clearly demonstrated that Oct v 1 is tropomyosin, similar to the known molluscan and crustacean allergens. Using peptide fragments isolated from the lysylendopeptidase digest of Oct v 1, competitive enzyme-linked immunosorbant assay inhibition experiments showed that IgE-binding epitopes of Oct v 1 are contained in two peptides (77–112 and 148–160) in the central region and one peptide (269–281) in the C-terminal region. In the peptide 77–112, the same sequence as the IgE-binding epitope proposed for Cra g 1 (oyster Crassostrea gigas allergen) is recognized at 92-105. Moreover, the peptide 148-160 partly overlaps with the IgE-binding epitopes suggested for Pen i 1 (shrimp Penaeus indicus allergen) and Pen a 1 (shrimp Penaeus aztecus allergen), and the peptide 269–281 with those for Tur c 1 and Pen a 1.     

Effect of two fresh diets and sexual maturation on the proximate and fatty acid profile of several tissues in Octopus vulgaris: specific retention of arachidonic acid in the gonads

Most nutritional studies on Octopus vulgaris were based on males to avoid interaction with reproductive processes, focusing on muscle and digestive gland tissues. This study intends to evaluate the effect of two fresh diets, a fish diet (bogue Boops boops) and a mixed diet (600 g kg^?1 crab Portunus pelagicus and 400 g kg^?1 bogue), on the biochemical composition of muscle, digestive gland and gonad in males and females of O. vulgaris. Six octopuses per diet were selected (n = 3 per sex) after 60 days of rearing in floating cages. Weight increase was higher in males (3–3.2 kg) than in females (0.9 kg) regardless of diet associated with sexual maturation. Gondosomatic Index in females was 11.3–13.4%. High‐lipid content in fish (440 g kg^?1 dw) was reflected in digestive gland regardless of the diet, while muscle and testis showed a relatively stable composition. The increase in protein content in the ovary was related to sexual maturation. The low arachidonic content in bogue was reflected in all tissues, with no apparent negative effect on growth and welfare. However, specific retention of arachidonic in the gonads, related to high arachidonic content in crab, underlined the importance of this fatty acid in for gonad development in O. vulgaris.     

Changes in lipid composition of different tissues of common octopus (Octopus vulgaris) during short‐term starvation

In this work, we study the variations in concentration (mg 100 g^?1 dry weight) and total content (mg individual^?1) of different lipid classes in muscle and the digestive gland of Octopus vulgaris during an 8‐day starvation period. In all the samples analysed, polar lipids (PL) predominated in muscle (267.3–337.2 mg 100 g^?1) compared with neutral lipids (66.9–104.7 mg 100 g^?1). A significant positive tendency was observed in muscle for the content and concentration of monoglycerides as a consequence of starvation (P < 0.05). Furthermore, a higher cholesterol (CHO) content was detected in this tissue after the fourth day of starvation compared with the fed animals (P < 0.05). Neutral lipids predominated in the digestive gland (12 958–14 151 mg 100 g^?1) compared with PL (3157–6517 mg 100 g^?1), with triglycerides, free fatty acids and monoglycerides being the major lipid classes. The concentration of PL and monoglycerides showed a positive trend with starvation, while the triacylglycerol showed a negative tendency (P < 0.05). The results suggest that triglycerides and CHO are transported simultaneously from the digestive gland to the muscular tissues during starvation and the preferential use of PL and CHO during growth phases. It was estimated that lipids contributed 26% of the energy costs of the animals during starvation, mainly in the form of triglycerides from the digestive gland.     

真蛸染色体核型分析

以东海沿海捕获的野生真蛸(Octopus sinensis)为实验材料,用含秋水仙素终浓度为0.005%的海水活体暂养的方法,取鳃和肾脏细胞,利用热滴片法制备染色体标本,对其核型进行分析。结果显示,真蛸的二倍体染色体条数为60条,核型公式为2n=14 m+26 sm+12 st+8 t,其染色体臂数(NF)为100。未发现带有随体和次溢痕的染色体和异型染色体,推断真蛸可能为常染色体性别决定类型。本研究可为蛸属的细胞遗传学研究及真蛸种质鉴定和资源保护提供基础资料和参考依据。     

Effects of supplementation of decapod zoea to Artemia basal diet on fatty acid composition and digestive gland histology in common octopus (Octopus vulgaris) paralarvae

The present study aimed to evaluate the effect of the supplementation of different crab zoeas to enriched Artemia basal diet for Octopus vulgaris paralarvae during the first month of life. Paralarvae were fed using enriched Artemia nauplii alone and Artemia co‐fed either first zoea stages of Grapsus adscensionis or Plagusia depressa. The experiment was carried out over a period of 28 days, in 0.12 m³ tanks with a flow‐through rearing system. Growth in dry weight as well as mantle length and width were assessed weekly. Additionally, prey and paralarvae fatty acid composition and digestive gland (DG) histology were evaluated. Addition of low amounts of crab zoeas (approx. 100 indv. L^?1 day^?1) provided during critical life stages of O. vulgaris proved to be good enough to improve paralarvae growth and survival in comparison with those fed exclusively on enriched Artemia. These results were supported by the finding of a higher number of glycoprotein absorption vacuoles in the DG from paralarvae co‐fed crab zoeas, suggesting a higher feeding activity. In addition, fatty acid analysis of crab zoea showed that these are good sources of dietary arachidonic and eicosapentaenoic acids during the octopus planktonic life stage, whereas the low docosahexaenoic (DHA) content suggests the use of additional DHA sources or higher zoea densities to meet paralarvae nutritional demand to carry out a successful metamorphosis to benthic life.     

真蛸染色体核型分析

以东海沿海捕获的野生真蛸(Octopus sinensis)为实验材料,用含秋水仙素终浓度为0.005%的海水活体暂养的方法,取鳃和肾脏细胞,利用热滴片法制备染色体标本,对其核型进行分析。结果显示,真蛸的二倍体染色体条数为60条,核型公式为2n=14 m+26 sm+12 st+8 t,其染色体臂数(NF)为100。未发现带有随体和次溢痕的染色体和异型染色体,推断真蛸可能为常染色体性别决定类型。本研究可为蛸属的细胞遗传学研究及真蛸种质鉴定和资源保护提供基础资料和参考依据。     

不同饵料对真蛸浮游幼体生长和存活的影响

为了满足真蛸浮游幼体阶段的营养需要,研究了几种饵料生物对真蛸浮游幼体的育苗效果。结果表明:轮虫不宜作为真蛸浮游幼体的生物饵料;恒温培养试验得出混合营养强化的丰年虫幼体的育苗效果优于混合营养强化的蒙古裸腹溞,并优于小球藻强化的丰年虫幼体及蒙古裸腹溞;常温试验得出梭子蟹溞状幼体+丰年虫幼体组合的饵料效果最好,而微囊营养强化剂强化的丰年虫幼体的育苗效果好于混合营养组合。综上所述,可认为:梭子蟹溞状幼体+丰年虫幼体组合是真蛸浮游幼体期比较适宜的饵料。     

真蛸早期发育形态特征及生长规律研究

为了探究真蛸(Octopus vulgaris)早期幼体生长发育特征,在室内水泥池育苗条件下,研究了孵化后1~100日龄真蛸的形态变化特征,并对1~49日龄真蛸的全长、腕长、胴长、胴宽、体重及最长腕的吸盘个数进行了测量。结果显示,在盐度为30~32,水温为18.6℃~26.0℃条件下,初孵仔蛸平均全长为(3.05±0.11) mm,大部分初孵仔蛸外卵黄囊在出膜前已吸收完毕,1日龄仔蛸已开口摄食,17日龄稚蛸开始摄食糠虾,35日龄稚蛸开始营底栖生活,60日龄体色由透明发育为乳白色,80日龄体色已与成体相同,100日龄除性腺外,各器官发育成熟,形态特征与成体基本一致。研究表明,真蛸早期(1~49日龄)发育过程中,体重与全长呈立方函数关系,为y=5×10–5x3– 0.0009x2+0.0072x–0.0132;全长与腕长呈立方函数关系,为y=–0.0012x3+0.0492x2+0.0243x+0.2179;全长、体重、腕长、胴长、胴宽分别与日龄呈立方函数关系,为y=–0.0001x3+0.0105x2–0.0122x+3.0562、y=–2×10–7x3+4×10–5x2–0.0004x+0.0034、y=–0.0004x3+0.0247x2–0.1037x+0.8214、y=–0.0004x3+0.0124x2 +0.0749x+1.4757、y=–3×10–5x3+0.0025x2+0.0354x+1.4026。依据营养类型、形态和生物学特征等参数,将真蛸早期发育分为仔蛸期、稚蛸浮游期、稚蛸底栖期和幼蛸期4个时期。     

Effective use of glucose rather than starch in formulated semimoist diets of common octopus (Octopus vulgaris)

The aim of the present work was to test the capacity of O. vulgaris to use carbohydrates supplied in three diets: a diet without added carbohydrates (diet C0: 500 g kg^?1 water, 200 g kg^?1 gelatine, 100 g kg^?1 egg yolk powder, 50 g kg^?1 freeze‐dried Sardinella aurita and 150 g kg^?1 freeze‐dried Todarodes sagittatus), and two obtained by substituting 50 g kg^?1 of T. sagittatus by glucose (diet GLU50) or by starch (diet STA50). The most stable and best accepted diet was STA50 (SFR 1.26%BW day^?1), although there were no significant differences in the growth rates obtained with the three diets: 10.1 g day^?1, 9.4 g day^?1 and 11.2 g day^?1 for C0, GLU50 and STA50, respectively (P > 0.05). The feed efficiency indices were better for GLU50, of particular note being the protein productive value of 72% and a feed conversion ratio lower than 1. Protein and lipid digestibility were similar in all three diets (96–98% for proteins and 85–94% for lipids), whereas carbohydrate digestibility was higher in GLU50 (98%) than in C0 (84%) and STA50 (0.33%). The content of carbohydrates increased in muscle and the digestive gland as a consequence of the increased carbohydrates intake.     

Effective use of glucose rather than starch in formulated semimoist diets of common octopus (Octopus vulgaris)

The aim of the present work was to test the capacity of Octopus vulgaris to use carbohydrates supplied in three diets: a diet without added carbohydrates (diet C0: 500 g kg^?1 water, 200 g kg^?1 gelatine, 100 g kg^?1 egg yolk powder, 50 g kg^?1 freeze‐dried Sardinella aurita and 150 g kg^?1 freeze‐dried Todarodes sagittatus) and two obtained by substituting 50 g kg^?1 of T. sagittatus by glucose (diet GLU50) or by starch (diet STA50). The most stable and best‐accepted diet was STA50 (SFR 1.26%BW day^?1) although there were no significant differences in the growth rates obtained with the three diets: 10.12 g day^?1, 9.37 g day^?1 and 11.22 g day^?1 for C0, GLU50 and STA50, respectively (P > 0.05). The feed efficiency indices were better for GLU50, of particular note being the protein productive value of 71.88% and a feed conversion ratio lower than 1. Protein and lipid digestibility were similar in all the three diets (96–98% for proteins and 85–94% for lipids), whereas carbohydrate digestibility was higher in GLU50 (98%) than in C0 (84%) and STA50 (0.33%). The content of carbohydrates increased in muscle and the digestive gland as a consequence of the increased carbohydrates intake.     

Effects of a dry pelleted diet on growth and survival of the Yucatan octopus, Octopus maya

The effect of a dry pelleted diet on growth of the Yucatan octopus (Octopus maya) was determined and compared with crab diet (Callinectes spp). Two groups of 15 wild collected animals were used. Octopuses were placed in isolation, in a flow‐through system composed of 30 circular tanks (80 L), with a bottom of 40 cm in diameter and a water depth of 80 cm. Experiment lasted 40 days, and octopuses were weighed every 10 days to determine growth rates. Octopuses were fed between 7% and 10% body weight (BW) per day, twice a day at 9:00 h and 17:00 h. Uneaten food was removed after 4 h in the tanks and weighed, to determine food ingestion and conversion. No mortality as a result of natural causes was observed. The 15 octopuses fed on frozen crabs and the 15 fed on the artificial diet had similar weights (P > 0.05) at the start of the experiment, of 486.2 ± 214.8 and 472.5 ± 228.3 g, respectively. At the end of the experiment, octopuses fed on frozen crabs weighed 1466.5 ± 484.0 g, and were significantly larger (P < 0.05), than octopuses fed on artificial diets (438.9 ± 202.6 g). Growth rates for the experiment were of 3.3 ± 0.2 and –0.0 ± 0.3% BW per day, for octopuses fed frozen crabs and the artificial diet, respectively. The artificial diet did not promote growth, but animals did not loose weight and more important, ate regularly all the food supplied, with feeding rates higher than reported in the literature for prepared diets. This makes O. maya a good research animal for the development of artificial diets for cephalopods.     

Fatty acid composition of polar and neutral lipid fractions of Octopus vulgaris Cuvier, 1797 paralarvae reared with enriched on‐grown Artemia

Rearing of common octopus Octopus vulgaris is limited by the lack of success during the paralarval stage, with generalized mortalities occurring before the settlement of the juveniles. The use of on‐grown Artemia cultured with the microalga Isochrysis galbana and further enriched with Nannochloropsis sp. has led to a certain degree of success. The present work aims at studying the effects of this rearing protocol (Nanno) on the fatty acid composition of paralarvae, by comparison with a diet based on on‐grown Artemia further enriched with a high polyunsaturated fatty acid oil emulsion (M70). After 28 days, survival was estimated at 3% for M70 and 22.5% for Nanno, whereas the average dry weight was not significantly different (Nanno: 1.76± 0.28 mg; M70: 1.88±0.22 mg). Although apparently no clear association between the fatty acid composition of the enriched preys and that of the total lipids of paralarvae could be established, further fractionation and fatty acid analysis of the total lipids into polar and neutral classes, followed by principal components analysis, revealed that irrespective of the diet, both lipid fractions showed distinct fatty acid patterns. Besides, the fatty acid composition of the polar lipids was more conservative, whereas that of the neutral lipids was more influenced by the diet, showing more variation among dietary treatments.