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1.
The importance of dietary 20:5n‐3 (EPA), 22:6n‐3 (DHA) and 20:4n‐6 (ARA) for growth, survival and fatty acid composition of juvenile cockles (Cerastoderma edule) was investigated. Cockles of 6.24 ± 0.04 mm and 66.14 ± 0.34 mg (live weight) were distributed into three treatments where live microalgae diets were fed constantly below the pseudofaeces production threshold, for three weeks. Diets had distinct fatty acid profiles: high EPA (53% Chaetoceros muelleri + 47% Pyramimonas parkeae), no DHA (47% Brachiomonas submarina + 53% Tetraselmis suecica) and low ARA concentrations (73% P. parkeae + 27% Phaeodactylum tricornutum). Growth was positively affected by high EPA and low ARA diets, whereas no significant growth was observed for the no DHA diet. High mortality of cockles fed no DHA diet raises questions about its suitability for cockles. In balanced diets with EPA and DHA, lower concentrations of ARA do not limit growth. The impact of dietary fatty acids was evident in the fatty acids of neutral and polar lipids of cockles. In polar lipids of all cockles, there was a decrease in EPA, in contrast to an increase in DHA. The combination of EPA and DHA in a live microalgae diet was beneficial for the growth and survival of juvenile cockles. 相似文献
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Chin‐Long Ky Carole Blay Vaite Aiho Philippe Cabral Gilles Le Moullac Cédrik Lo 《Aquaculture Research》2017,48(1):270-282
In French Polynesia, the aquaculture of Pinctada margaritifera is carried out in numerous grow‐out sites, located over three archipelagos (Gambier, Society and Tuamotu). To evaluate the impact of macro‐geographical effects of these growing sites on pearl quality traits, five hatcheries produced families were used as homogeneous donor oysters in an experimental graft. The molluscs were then reared in two commercial locations: Tahaa Island (Society) and Rangiroa atoll (Tuamotu). At harvest, eight pearl quality traits were recorded and compared: surface defects, lustre, grade, circles, shape categories, darkness level, body and secondary colour and visual colour categories. Overall inter‐site comparison revealed that: (1) all traits were affected by grow‐out location except for lustre and round shape, and (2) a higher mean rate of valuable pearls was produced in Rangiroa. Indeed, for pearl grade, Rangiroa showed twice as many A‐B and less reject samples than Tahaa. This was related to the number of surface defects (grade component): in Rangiroa, twice as many pearls had no defects and less pearls had up to 10 defects. Concerning pearl shape, more circled and baroque pearls were found in Tahaa (+10%). For colour variation, 10% more pearls have an attractive green overtone in Rangiroa than in Tahaa, where more grey body colour were harvested. Lustre does not seem to be affected by these two culture site (except at a family scale). This is the first time P. margaritifera donor family have been shown to vary in the quality of pearls they produce depending on their grow‐out location. 相似文献
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Marie Antonette Juinio‐Meñez Julissah C Evangelio Sasa James A Miralao 《Aquaculture Research》2014,45(8):1332-1340
Field trials were conducted to determine the effects of size, grow‐out period and site on the growth and survival of Holothuria scabra. Juveniles were reared in sea cages in two sites for 2 months during two different times of the year. Juveniles from Experiment 1 were subsequently grown in sea pens for 8 months in one site. The significantly lower survival particularly of the small‐sized group (<0.1 g) in Pilar is likely due to reduced water and sediment quality because of proximity to fish‐farming activities. The importance of grow‐out period was evident in the significant differences in weight increments in all size groups and biomass in the small‐sized group (P < 0.10) in Lucero during Experiment 2 when water temperature range and incidence of rainfall were higher. The decrease in the average weight of adults during the second half of the grow‐out period may be due to the interplay of the reduction in salinity, onset of sexual maturity and biomass exceeding carrying capacity in the pens. The estimated biomass threshold in the sea cages and pens in Lucero were 300 g m?2 and 380 g m?2 respectively. Implications of the results on the viability of small‐scale pen grow‐out culture are discussed. 相似文献
5.
Netminder®, a water‐based silicone barrier release coating, was highly effective in reducing biofouling of lantern nets during grow‐out/overwintering of bay scallops, Argopecten irradians irradians, in a large‐scale restoration programme in New York, USA. Compared with untreated nets, scallops held in Netminder®‐coated nets experienced reduced survival after 8 months, probably due to higher loads of epibionts on their shells. However, this was countered by higher reproductive and overall condition of scallops in treated vs. untreated nets; there were no consistent differences in shell growth in different net treatments. Although further testing is recommended under a wider range of conditions, we conclude that for the purposes of our scallop restoration work, coating nets with Netminder® would eliminate the need for a gear change in spring, thus reducing labour costs; the coating process should be refined so that Velcro closures of nets do not become sealed shut. 相似文献
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The promotion of Blue Growth in aquaculture requires an understanding of the economic drivers influencing the sector at farm level, but the collection of reliable and comparable data at this level is time‐consuming and expensive. This study suggests an alternative strategy for qualitative sampling of freshwater trout farms in Germany, Denmark and Turkey, using a combination of existing data, group discussions and interviews with trout farmers, consultants and researchers. Nine ‘typical’ trout farming models are described, focusing on profitability, productivity and energy efficiency and allowing in‐depth comparative economic analyses of different production systems at farm level, across regions. Our results show that the majority of the farms investigated have been profitable. Turkish farms benefit from competitive advantages due to low wages, low capital investment and favourable climate conditions. Large German farms profit from local market prices and advanced farm management. Danish farms using recirculating techniques remain competitive thanks to enhanced productivity and economy of scale. However, small traditional farms in Germany and Denmark may struggle to stay competitive in the long term. Organic farms in both countries face challenges of high feed costs and comparatively low productivity with mixed success. Using edible protein energy return on investment (epEROI) as an indicator of ecological sustainability, all surveyed farms compared very favourably with the terrestrial systems of animal meat production were investigated so far. 相似文献
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Helen Gurney‐Smith Nadia Plamondon Simon Yuan Christopher M Pearce 《Aquaculture Research》2013,44(8):1236-1253
The basket cockle (Clinocardium nuttallii) is a candidate species for aquaculture in the northeast Pacific. The aim of the current research was to assess the feasibility of C. nuttallii grow‐out, with an emphasis on growth performance and qualities affecting product marketability. In this article, we investigated the combined effects of culture mode (intertidal and off‐bottom suspended culture) and initial stocking density (1500, 3000, 10 500 and 21 000 ind m?2) on C. nuttallii survival and growth during the first year of grow‐out (May through October). In intertidal culture, cockles exhibited low survival and poor growth rates. In suspended culture, survival was consistently high (>96%) at all stocking densities tested; growth and condition parameters had the highest values at 1500 and 3000 ind m?2. The edible portion (meat yield) exceeded 40% of the whole wet weight at all stocking densities, occurrences of fouled and deformed cockles were <1% and no commensal species were observed. Depending on the minimum harvestable size and stocking density chosen, harvestable proportions constituted from 1.1% to 15.2% by October of the first grow‐out year in the suspended system. The effects of stocking density and depth on second year grow‐out performance of C. nuttallii are reported in a companion paper (Dunham et al. in this issue). 相似文献
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Catarina Anjos Teresa Baptista Sandra Joaquim Susana Mendes Ana Margarete Matias Paula Moura Tiago Simões Domitília Matias 《Aquaculture Research》2017,48(7):3859-3878
The Portuguese oyster Crassostrea angulata shows great potential in oyster farming. The conservation of pure populations of this species is important for production diversification and biodiversity preservation. In this way, the zootechnological development for seed hatchery production is extremely important. Broodstock conditioning is a key step in the process of rearing bivalves in a hatchery. Many factors regulate the reproductive cycle, being food one of the most important ones. To evaluate the effect of different diets on C. angulata reproductive performance, broodstock were conditioned with different food regimes formulated fundamentally by flagellates (Diet 1 – Pavlova lutheri and Isochrysis galbana clone T‐ISO; Diet 2 – P. lutheri, T‐ISO and Skeletonema costatum) and constituted fundamentally by diatoms (Diet 3 – S. costatum and Chaetoceros calcitrans; Diet 4 – P. lutheri, S. costatum and C. calcitrans). During conditioning, samples of oysters were collected to evaluate condition index, gonadal development and biochemical composition. At the end of the conditioning period, oysters were induced to spawn to evaluate reproductive output (fecundity, fertilization rate and D‐larvae development). The diets had an impact on the gametogenesis process, energy storage and reproductive output performance, being the best results those obtained in broodstock fed with the diatoms‐predominant diets. However, those fed with diets majority flagellates had an unsuccessful performance. Holistic approaches incorporating all results in this study reveal and reinforce the idea that the diatom species used presented the nutritional requirements to C. angulata broodstock, being essential in the conditioning phase. 相似文献
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Mariam Hamdan Ana Tomás‐Vidal Silvia Martínez Jesus Cerezo‐Valverde Francisco J Moyano 《Aquaculture Research》2014,45(12):2048-2056
An in vitro model designed to assess protein bioavailability in diets for growing Octopus was developed. The model required a previous assessment of some functional features of protein digestion in this species like the main producing organs, optimum pH for activity and total production per g tissue. The main producing organs identified were the salivary glands and the hepatopancreas (HP), being optimum pH for protease activity quite different in both organs (mostly alkaline in the posterior salivary glands and acid in the HP). In spite of the high‐specific protease activity measured in the salivary glands, a major role of the HP in protein hydrolysis is suggested due to the much bigger size of this viscera. All this information was used as a basis to develop an in vitro two‐step hydrolysis process, which simulated protein hydrolysis performed by these two organs using the Octopus enzymes. The assay was used to evaluate differences in amino acid bioavailability from several protein sources (casein, gelatin, fish meal, squid meal and krill meal) that could be used as feed ingredients for this species. As significant differences were detected both in total amount and in rate of release of the amino acids from such proteins, the model is proposed as a complementary tool in the selection and nutritional evaluation of protein ingredients to be used in diets for Octopus. 相似文献
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Xiaobo Yan Junjiang Yang Xiaohui Dong Beiping Tan Shuang Zhang Shuyan Chi Qihui Yang Hongyu Liu Yuanzhi Yang 《Aquaculture Nutrition》2020,26(5):1555-1567
The present study was conducted to investigate the protein requirement of grouper Epinephelus coioides at grow‐out stage (initial weight of 102.8 ± 1.02 g). Six iso‐lipidic diets were formulated using white fish meal and casein as protein sources with graded levels of protein (350, 400, 450, 500, 550 and 600 g/kg). Grouper was hand‐fed twice daily to apparent satiation in triplicates for 8 weeks. The results showed that lack of protein will lead to the declined of weight gain and specific growth rate and suitable protein not only improved growth, but also reduced feed coefficient rate. In addition, high‐protein level diet significantly decreased the morphological index of grouper. For the body proximate composition analysis, the high‐protein diets (500, 550, 600 g/kg) significantly increased the protein contents in the whole body and muscle which was contrary to as observed for the lipid content. High‐protein diets significantly improved the total protein levels of plasma which were contrast to as observed in triglyceride contents. Moreso, the cholesterol content was observed to be significantly decreased after high‐protein diet supplementation. The intestinal protease activity was observed to increase significantly with increasing protein supplementation whereas a decreasing trend was observed for the lipase and amylase activity with the highest going for the groups fed diets containing 350 g/kg protein as compared to the others. The liver alkaline phosphatase, superoxide dismutase and lysozyme activity increased with increasing protein level which later decreased. On the other hand, the acid phosphatase activity showed a significant downward trend. Based on SGR, the broken‐line regression analysis showed that the optimum dietary protein level and digestible protein level of the grouper Epinephelus coioides at grow‐out stage were 466.65 and 395.79 g/kg, respectively. 相似文献
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Ajay Kumar Yadav Sagar Chandra Mandal Arun Bhai Patel Pradip Kumar Maurya 《Aquaculture Research》2019,50(11):3343-3349
An experiment was designed to evaluate the requirement of dietary protein for Reba carp, Cirrhinus reba fingerlings using semi‐purified diet. Five isocaloric diets were prepared containing 20%, 25%, 30%, 35% and 40% level of protein using casein, gelatin as a major protein source. The experiment was conducted for 105 days in triplicates to evaluate the growth, survival, feed utilization, carcass composition of C. reba. Mean weight gain was highest (p < .05) in T3. Specific growth rate was highest in T3 and lowest in T1. Similarly, significantly (p < .05) highest net fish yield were recorded in T3. No significant difference was recorded in survivability. Feed conversion ratio, protein efficiency ratio, feed conversion efficiency and protein conversion efficiency were significantly (p < .05) higher for T3 compared with other treatments. Highest carcass protein and lipid values were recorded in T3. So, conclusion can be drawn that 30% crude protein is optimum for overall performance. Furthermore, broken‐line analysis for specific growth rate, final biomass and net fish yield indicated that dietary protein level of 28.148 to 28.253% is optimum for the best growth performance of fingerling C. reba. 相似文献
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E. B. Thorstad I. Uglem B. Finstad C. M. Chittenden R. Nilsen F. Økland P. A. Bjørn 《Fisheries Management and Ecology》2012,19(5):400-409
Abstract Release strategies of hatchery‐reared Atlantic salmon, Salmo salar L., smolts were compared by studying survival and migration of smolts (n = 99) and their predators (Atlantic cod, Gadus morhua L., n = 8; and saithe, Pollachius virens (L.), n = 2) during the first 37 km of the marine migration using acoustic telemetry. Survivorship was higher in smolts released at the river mouth (30%) compared with smolts released in the river (12%). This was likely due to mortality or reduced migratory behaviour in fresh water. The marine mortality was 37% during the first 2 km after leaving the river (at least 25% mortality because of predation from marine fishes), and total marine mortality over 37 km was 68%. Detection‐depth data were useful for evaluating whether the tagged smolts were alive or predated; mortality during the first 2 km of outward migration would have been underestimated at 26% instead of 37% without the analysis of depth detection. Transmitters from consumed post‐smolts remained in predators for up to 47 days (average 29 days). 相似文献
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Fabiola Lafarga‐De la Cruz Gustavo Núñez‐Acuña Cristian Gallardo‐Escárate 《Aquaculture Research》2013,44(8):1206-1220
Two introduced abalone species are currently produced in Chile, red abalone Haliotis rufescens and Japanese abalone Haliotis discus hannai. However, red abalone accounts for 99% of total production, while the Japanese abalone has not adapted well to Chilean coastal waters. This study reports the hatching, growth and thermal tolerance performance in interspecific hybrids produced between red (R) and Japanese (J) abalone. Our results show that egg age and sperm concentration were critical factors to produce hybrids. The cross R♀ × J♂ showed a fertilization rate of 55.3 ± 3.5% using 20‐min‐old eggs and sperm concentrations of 14 × 106 cells mL?1, while the reciprocal cross (J♀ × R♂) was not successful. Further, larval development stages were similar in RR, JJ and RJ hybrid abalones. Among the experimental trials, settlement rate varied from 12.3% to 18.6% and final survival from 20.1% to 31.7%, being the RJ hybrid rates intermediate between parental species. The final shell lengths were similar between RR and RJ hybrids, but significantly higher in JJ abalones. In addition, thermal tolerance was ascertained due its pivotal role for the abalone physiology. Thus, RJ hybrids showed the highest HSP70 gene expression and offers new possibilities to expand Chilean abalone production in warm waters zones. 相似文献
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Marta Castilla‐Gaviln Bruno Cognie Emilie Ragueneau Vincent Turpin Priscilla Decottignies 《Aquaculture Research》2019,50(7):1762-1769
The aim of this work was to assess the potential use of different dried macroalgae as food in the rearing of Paracentrotus lividus. Growth, consumption and food conversions were compared in adult sea urchins fed with fresh or dried thalli of four macroalgae species. Six experimental diets were tested: (a) fresh Palmaria palmata; (b) fresh Saccharina latissima; (c) dry P. palmata; (d) dry S. latissima; (e) dry Laminaria digitata and (f) dry Grateloupia turuturu. Linear growth rates were similar for all treatments. Specific growth rate was higher in sea urchins fed with fresh P. palmata, but no difference was found between animals fed with fresh S. latissima and those fed with dried diets. Regarding daily food consumption (DFC), sea urchins consumed the same amount of dried macroalgae as fresh but exhibited a higher food conversion efficiency (FCE) when fed with fresh P. palmata. However, this FCE was only significantly higher when compared to sea urchins fed with dry L. digitata. Dried G. turuturu is not a suitable diet due to its rapid degradation after rehydration. The results suggest that P. lividus adults can be reared on dried macroalgae thalli without detriment to their somatic growth, especially over short periods. The low cost of feeding sea urchins with this diet could help small shellfish farmers to diversify their production into echinoculture. 相似文献
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Mussel aquaculture is widely prevalent worldwide, but generally relies on natural seed collection, which does not always meet the needs of the producers. Thus, development of mussel hatcheries is of economic interest in some parts of the world, such as Europe; it provides opportunities not only on annual reliability of seed but also on genetic improvements. To broaden knowledge on mussel larval physiology, we carried out temperature treatments (17, 20 and 24 °C) on Mytilus galloprovincialis larvae under laboratory conditions. The trials ended when 30% of the larval population was in the post‐larval stage. The temperature coefficient Q10 indicated a strong relationship between temperature and increase in growth from 17 to 20 °C, but not between 20 and 24 °C. Exposure of M. galloprovincialis larvae to 17 °C resulted in poor growth, low survival and a delayed development and was considered to be inadequate for M. galloprovincialis larval culture. Rearing the larvae at 20 or 24 °C produced better growth, higher survival rates and faster metamorphosis as compared with 17 °C. The temperature region within 20 and 24 °C was suggested as adequate for the mussel M. galloprovincialis larval culture, and implications of these results on the development of commercial hatcheries were discussed. 相似文献
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Artemia franciscana was studied under in vitro conditions, and fed with five different microalgae species, two organic diets and one mixed diet to evaluate the nutritional profile and growth performance. The A. franciscana instar‐I nauplii were stocked at a density of 100 per litre of ground borewell water with a salinity of 70 ppt in a plastic container and the culture continued for 12 days. The A. franciscana was fed with five microalgal species, such as Tetraselmis sp., Chaetoceros sp., Isochrysis sp., Thalassiosira sp. and Nannochloropsis sp., and organic diets of rice bran, soybean meal, and a mixture of Tetraselmis sp. and Chaetoceros sp. with rice bran, giving a total of eight experiments. The growth of A. franciscana was measured by length, and was observed to be the greatest (10,850 μm) in the group that was fed the mixed algae combination, and the lowest (7,290 μm) in the group that was fed Nannochloropsis sp. Among the different treatments, the highest survival value of 76% was seen in the group that was fed Chaetoceros sp. The fecundity was higher in A. franciscana that were fed with algae Chaetoceros sp., while the lower rate was observed with the group that was fed Nannochloropsis sp. Analysis of proximate composition showed increased levels in the animals fed with Chaetoceros sp. (lipid, 19.40%; eicosapentaenoic acid, 6.70 mg; docosahexaenoic acid, 10.20 mg; amino acids: proline, 2.06 μg; histidine, 0.77 μg, arginine, 0.65 μg, glycine, 0.80 μg, glutamic acid, 1.75 μg; threonine, 1.42 μg) and the mixed diet (protein, 58.59%; carbohydrate, 21.30%; amino acids: asparagine, 0.90 μg; serine, 1.65 μg; tryptophan, 1.66 μg; leucine, 1.50 μg; phenylalanine, 1.14 μg; valine, 0.66 μg). All components showed the lowest level in the diet fed with Tetraselmis species. These A. franciscana populations showed better survival, higher fecundity and biochemical profiles when cultured with microalgae Chaetoceros sp. These data are useful to improve A. franciscana culture in aquaculture to produce quality cysts and biomass, especially in feeding larvae of marine species. 相似文献
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The present work investigates the effects of Chaetoceros calcitrans, Nannochloropsis oculata, Tetraselmis tetrahele and Isochrysis galbana diets on the lifespan, growth, neonate production and the nutritional profile of Diaphanosoma celebensis. In addition, the effects of enriched D. celebensis on the survival and growth of Litopenaeus vannamei postlarvae (PLs) was compared with Artemia. Results showed that significantly higher (P < 0.05) neonate production of D. celebensis was attained when fed with C. calcitrans compared to the other microalgae. In addition, D. celebensis fed on C. calcitrans had significantly higher levels (P < 0.05) of protein, lipid and carbohydrate compared to the other three microalgae. On the other hand, D. celebensis had a significantly (P < 0.05) longer lifespan when fed on N. oculata and T. tetrahele compared to those fed with C. calcitrans and I. galbana. Shrimp PLs fed D. celebensis enriched with C. calcitrans had higher survival and specific growth rate but it was not significantly different (P > 0.05) from PL fed only Artemia, indicating that D. celebensis has potential to be used as live feed for the hatchery rearing of L. vannamei PLs, in place of Artemia. This study illustrated that the quality of the D. celebensis production and proximate composition was highly correlated with the food type, and it can be used as a valuable live feed for shrimp larviculture. 相似文献
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Many studies have documented that hatchery‐reared salmonids generally have inferior survival after being stocked compared with wild conspecifics, hatchery and wild salmonids have been observed to differ in their antipredator responses. The response of brown trout (Salmo trutta) juveniles (0+) of differing backgrounds to a live predator was compared in two experiments. First, the antipredator behaviour of predator‐naïve hatchery‐reared brown trout and wild‐exposed brown trout were assessed in behavioural trials which lasted for eight days. Second, predator‐naïve and predator‐conditioned hatchery‐reared brown trout were assessed in identical behavioural trials. Brown trout were ‘predator‐conditioned’ by being held in a stream‐water aquarium with adult Atlantic salmon (Salmo salar) and adult brown trout for two days prior to behavioural trials. Predator‐conditioned hatchery‐reared brown trout spent more time in shelters in the trial aquaria than predator‐naïve hatchery‐reared fish, but did not differ in time spent in the predator‐free area. Predator conditioning may account for the increased time spent in the shelter, but does not appear to have affected time spent in the predator‐free area. However, even if significant alteration in behaviour can be noted in the laboratory, the response might not be appropriate in the wild. 相似文献
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A greater understanding of dietary protein and carbohydrate levels with regard to gonad production in Strongylocentrotus purpuratus would increase our nutritional knowledge of this sea urchin and guide the development of formulated diets for such aquaculture target species. A total of 255 purple sea urchins were captured from Ensenada Bay, Mexico, and maintained in 200‐L tanks for 9 weeks. Formulated diets that contained 30%, 26%, 23%, 20% and 17% of protein and 42%, 46%, 50%, 54% and 58% carbohydrates were offered ad libitum. Survival was affected by diets; urchins that were fed high‐protein–low‐carbohydrate diet experienced decreased survival. No significant differences were found in gonad index, but gonad production efficiency was lower in urchins that were fed a medium‐low‐protein–medium‐high‐carbohydrate diet. Urchins that were fed high carbohydrate levels utilized protein more efficiently and showed better digestibility of the diet and protein. These data suggest that all of our diets support gonad growth, but in terms of consumption, a diet that contains protein levels of 17% and 23% with carbohydrate levels of 50% and 58% are beneficial for S. purpuratus. 相似文献