Two pathogens of Greenshell™ mussel larvae, Perna canaliculus: Vibrio splendidus and a V. coralliilyticus/neptunius-like isolate

Bacterial pathogens of Greenshell™ mussel (GSM) larvae can cause batch losses during hatchery production. Twenty-two isolates were screened using a larval bioassay. Two strains were identified as potential pathogens. Phenotypic identification of these strains revealed two non-reactive Gram-negative, oxidase positive rods. Sequencing of the 16S rRNA gene identified Vibrio splendidus and a V. coralliilyticus/neptunius -like isolate as pathogens of GSM larvae, with an ability to cause 83% and 75% larval mortality in vitro , respectively, at a concentration of 10² CFU mL⁻¹. Histopathology indicated that the route of infection was via the digestive system. Using healthy larvae as target hosts, Koch's postulates were confirmed for the two isolates. This is the first report on pathogens of GSM larvae.     

翡翠贻贝多糖抑制流感病毒在鸡胚中增殖的研究

采用血凝滴度法研究翡翠贻贝多糖(PVPS)对鸡胚培养甲型流感病毒的抑制作用;通过联合给药试验研究PVPS对利巴韦林抗流感病毒的协同效应。与病毒对照组比较,PVPS各剂量组的血凝滴度降低差异极显著(P<0.01)。与利巴韦林组及同剂量PVPS单独给药组相比,联合给药组的血凝滴度降低差异极显著(P<0.01),且0.85相似文献   

Effect of temperature on the development, growth, survival and settlement of green mussel Perna viridis (Linnaeus, 1758)

The effect of temperature on the development, growth, survival and settlement of Perna viridis was studied under controlled conditions to provide information needed for the development of commercial hatchery technology for green mussel P. viridis. Total mortality of the larvae occurred after 24 h at temperatures of 33°C and 35°C. At 24°C, larvae took longer to settle than at temperatures of 27°C, 29°C and 31°C. For optimum larval development (8–13 h), growth (17.2±0.84 μm day^–1) and survival (55.2±0.84%), a hatchery rearing temperature of 31°C is required. For settlement no significant difference was seen between the percentage settlement at 29°C (49.3±3.34%) and 31°C (45.8±1.76%). However, the process of settlement began and ended earlier at 29°C (from 15 to 18 days) than at 31°C (from 18 to 20 days). Thus for larval settlement a temperature of 29°C is recommended.     

Growth and mortality of Mediterranean mussel Mytilus galloprovincialis Lam., 1819, in relation to size on longline in Mersin Bay, Izmir (Turkey – Aegean Sea)

The growth and mortality rate of different size of mussels, Mytilus galloprovincialis, were compared in Mersin bay, Izmir. Mussel sampling was performed on a monthly basis over 1 year, together with hyrobiological parameters. Water temperature, salinity, chlorophyll a, total particulate matter (TPM) and particulate organic carbon (POC) were determined. Average chlorophyll a, TPM and POC values were 3.88±1.62 μg L⁻¹, 13.12±3.68 mg L⁻¹ and 252±121.89 μg L⁻¹ respectively. Initial mean lengths of mussels for each size group were 10 mm (9.91±0.25 mm), 20 mm (20.14±0.29 mm), 30 mm (30.66±0.21 mm), 40 mm (40.14±0.21 mm), 50 mm (50.62±0.21 mm), 60 mm (59.77±0.21 mm) and 70 mm (69.47±0.62 mm). Maximum growth in length occurred during the spring–summer months. The annual length increments of mussel size groups were 46.22, 41.42, 30.3, 28.03, 20.63, 16.34 and 12.03 mm from small to large size groups respectively. Small mussels grew faster than large mussels and reached commercial size at the same time. Mortality was <5% for all groups at the end of the experiment.     

Development and evaluation of microsatellite markers for identification of individual Greenshell™ mussels (Perna canaliculus) in a selective breeding programme

A set of 49 microsatellite loci isolated from the endemic New Zealand Greenshell™ mussel, Perna canaliculus, were evaluated for inclusion in a parentage assignment marker suite by assessing their ease of PCR amplification, allele scoring and conformity to Mendelian inheritance in hatchery-produced families. Ten polymorphic loci (mean H_e = 0.78 and polymorphic information content (PIC) = 0.72) were identified as being suitable for parentage assignment. These 10 microsatellite loci gave a combined non-exclusion probability of < 0.001 (probability that an unrelated parent pair will not be excluded from parentage of an arbitrary offspring), based on allele frequencies from 16 broodstock mussels. Simulations predicted an assignment success rate of 99.9% with all 10 loci and > 95% with the best 5 or more loci (mean PIC = 0.84). In actual parentage assignments, 124 offspring from 8 full-sib families were assigned to the correct parent pair with 4 or more loci. We found evidence for null alleles and extensive size homoplasy in many loci, highlighting the importance of thoroughly characterizing and evaluating microsatellite markers prior to parentage assignment and other applications.     

Growth and survival of first-feeding spotted wolffish (Anarhichas minor Olafsen) at various temperature regimes

In order to define temperature regimes that could benefit successful production of spotted wolffish (Anarhichas minor) juveniles, experiments with offspring from two different females were carried out. The larvae were fed a new formulated feed or a commercial start‐feed for marine fish, both of which have given high survival rates. In the first experiment newly hatched larvae were fed at constant 6 °C, 8 °C, 10 °C and 12 °C as well as at ambient seawater temperature (2.9–4.5 °C) during 63 days. High survival, 90% to 96%, was registered at ambient and most constant temperature regimes, whereas in the 12 °C groups survival was reduced to 80%. Growth rate (SGR) was very low, 1.8% day^?1, at the low ambient temperatures. Growth rate was positively correlated with temperature and varied between 3.1% day^?1 to 4.7% day^?1, from 6 °C to 12 °C. In the second experiment, set up to include potential detrimental temperatures and study beneficial effects of a more restricted, elevated first‐feeding temperature regime, the larvae were fed at constant 8 °C, 10 °C, 12 °C, 14 °C and 16 °C until 30 days post hatch, followed by constant 8 °C for the next 33 days. In this experiment, low survival, 25% and 2.0%, was registered at 63 days post hatch when larvae were reared initially at 14 °C and 16 °C respectively. The survival of the larvae at the other temperature regimes varied from 47% to 64%, highest survival rate (64%) was found at 8 °C. The lowest specific growth rate, 2.6% day^?1, was noted in the 16 °C group. At constant 8 °C to 14 °C (regulated to 8 °C), the SGR varied from 4.45% day^?1 to 5.13% day^?1. The larvae grew faster in the experiment when initially comparable temperatures (8 °C, 10 °C and 12 °C) were regulated to constant 8 °C after 30 days compared with the first experiment where feeding was carried out at the same constant temperatures (8 °C, 10 °C and 12 °C) during the whole experimental period.     

Growth and feeding responses of a hatchery population of brown trout (Salmo trutta L.) at low temperatures

Abstract— Feed intake, specific growth rate and changes in body composition were studied in age 1+ (140-190 g) brown trout ( Salmo trutta L.) reared at three temperatures (2, 4 and 6°C) under continuous light conditions. Feed in take increased from 35.7 kJ-kg⁻¹.day⁻¹ at 2°C to 95.7 kJ-kg⁻¹-day⁻¹ at 6°C, and the growth rate increased from 0.19%-day⁻¹ to 0.42%-day⁻¹ over the same temperature range. The estimated lower temperature limits for feeding and growth were slightly above 0°C. For all groups of fish, the majority (about 75%) of the weight gain comprised water and protein, but lipid deposition tended to increase with increasing temperature. The deposition of lipid accounted for about 50% of the body energy gain at all temperatures.     

Growth of young cuttlefish, Sepia officinalis (Linnaeus 1758) at the upper end of the biological distribution temperature range

Individual growth rates, feeding rates (%BWd^?1) and food conversions for cuttlefish (S. officinalis) hatchlings and juveniles were determined during this study. A flow‐through system was used. Water temperature reached 30 °C during the hottest part of the day, gradually decreasing to 25 °C during the night; salinity varied between 37 ± 3 ppt and lights were kept on for 14 h day^?1. Hatchlings were placed in separate compartments with a water volume of 1.2 L. Juvenile cuttlefish (from 0.5 to 25 g) were placed in bigger baskets, with a water volume of 5.2 L. Water flow was 120 L h^?1. The biggest cuttlefish used in these experiments (> 25 g) were gathered in groups of five and placed in circular tanks (water volume of 250–300 L). Thus, results obtained in this case are means and not individual data. During the first 10, 20, 30 and 40 days, mean growth rates (of all individuals sampled by age group) decreased consistently (11.8 ± 4.1, 9.8 ± 1.8, 8.1 ± 2.2 and 7.3 ± 0.7%BW^?1 respectively); in similar fashion, mean feeding rates decreased with age group (33.7 ± 13.5, 22.0 ± 7.9, 17.3 ± 3.9 and 16.7%BWd^?1 respectively). Mean food conversions varied between 3.6 and 2.5 between the age groups. When grouping results by weight class, similar patterns occur, as growth and feeding rates decrease consistently as cuttlefish grow bigger. Highest mean growth and feeding rates are obtained by hatchlings (< 0.1 g) with 12.4 ± 4.5 and 35.3 ± 15.1%BWd^?1, respectively, while the lowest growth and feeding rates were recorded for the largest animals, between 15 and 25 g (3.4 ± 1.1 and 10.8 ± 4.1%BWd^?1 respectively). For these weight classes, mean food conversions varied between 2.7 ± 0.9 and 3.8 ± 2.8.     

不同脂肪含量的配合饲料对半滑舌鳎苗种生长的影响

通过不同脂肪含量饲料的对比喂养试验,初步了解半滑舌鳎（Cynoglossus semilaevis）对饲料中脂肪含量的需求,使用脂肪含量分别为10.9％、14.2％和16.6％的配合饲料对半滑舌鳎进行了60d的喂养试验.结果表明,用脂肪含量为10.9％的配合饲料喂养的半滑舌鳎生长情况优于其他两种更高脂肪含量的配合饲料....     

Growth and oxygen consumption of the juvenile sea cucumber Apostichopus japonicus (Selenka) at constant and fluctuating water temperatures

The effects of thermal amplitudes of diel fluctuating temperature on growth and oxygen consumption of the juvenile sea cucumber Apostichopus japonicus (Selenka) were studied at the average temperatures of 15 and 18°C with three diel different fluctuating amplitudes of ±2, ±4 and ±6°C. The optimum thermal amplitudes for growth of the juvenile sea cucumber at the sizes of this experiment, at average temperatures of 15 and 18°C, were estimated to be ±1.38 and ±1.67°C respectively. In the constant temperature regimes, the growth rate at 15°C was higher than that at 18°C. However, the growth rate at 18±2°C was higher than that at 15±2°C. The results from this study suggested that fluctuating temperatures enhanced the optimum temperature for the growth of sea cucumbers compared with that at constant temperatures. Therefore, accurate predictions of the optimum temperature of sea cucumbers in the natural environment, in which water temperatures fluctuate daily and seasonally, should be made from data obtained at fluctuating temperatures.     

Growth,feed utilization and body composition of Asian catfish (Pangasius hypophthalmus) fed at different dietary protein and lipid levels

This study examined the effect of dietary protein and lipid levels on growth, feed utilization and body composition of Asian catfish Pangasius hypophthalmus reared in cages. Eight test diets were formulated at four protein (340, 380, 420 and 460 g kg⁻¹ crude protein) and two lipid (50 and 90 g kg⁻¹ crude lipid) levels. Fish (initial weight 4.7 g fish⁻¹) were fed the test diets for 8 weeks. Final body weight, weight gain (WG), feed intake (FI), feed conversion ratio (FCR), contents of crude protein, lipid and energy in whole body were dependent on both dietary protein and lipid levels, while specific growth rate (SGR), hepatosomatic index and body moisture content were dependent on dietary lipid level. The WG and SGR increased with the increase in either dietary protein level (at the same lipid level) or lipid level (at the same protein level). The FI and FCR decreased with the increase in dietary protein level (at the same lipid level) or lipid level (at the same protein level). Protein sparing action occurred in case dietary lipid level increased. Fish fed the diet containing 453 g kg⁻¹ crude protein and 86 g kg⁻¹ lipid had the highest WG and SGR, but the lowest FI and FCR, among the diet treatments. There were no significant differences in the protein retention efficiency (PRE) and energy retention efficiency (ERE) among the diet treatments, although PRE and ERE were relatively high in fish fed the diet containing 453 g kg⁻¹ crude protein and 86 g kg⁻¹ lipid. At the end of the feeding trial, body protein content increased, while body lipid content decreased, with the increase in dietary protein content at the same lipid level. Our results suggest that dietary levels of 450 g kg⁻¹ crude protein and 90 g kg⁻¹ lipid are adequate to support fast growth of P. hypophthalmus reared in cages.     

Growth trials for polyculture of hatchery-reared juvenile spotted babylon (Babylonia areolata) and sea bass (Lates calcarifer) in a flow-through sea water system

Juvenile spotted babylon (Babylonia areolata) and sea bass (Lates calcarifer) were cultured in 11.5‐m³ indoor rearing tanks supplied with flow‐through of ambient natural sea water over a 120‐day experiment. Each species, stocked at the following densities for the following treatments, was tested with three replicates per treatment: 5000 B. areolata per tank (Treatment 1); 200 L. calcarifer per tank (Treatment 2); and 5000 B. areolata plus 200 L. calcarifer per tank (Treatment 3),. The average growth (length and weight), feed conversion ratio and total production of spotted babylon and sea bass from Treatment 3 were not significantly different from those of Treatment 1 and 2 (P > 0.05). Average survival rates for both spotted babylon and sea bass exceeded 95% for all treatments.     

Growth and performance of the whiteleg shrimp Penaeus vannamei (Boone) cultured in low‐salinity water with different stocking densities and acclimation times

We evaluated the performance of whiteleg shrimp Penaeus vannamei (Boone, 1931) in response to different stocking densities and acclimation periods. Shrimp postlarvae were acclimated from seawater (30 g L^?1) to low‐salinity well water (<1.0 g L^?1) at a constant hourly reduction rate of 40, 60, 80 and 100 h. After acclimation to low‐salinity well water, postlarvae from each acclimation time treatment were stocked in three replicate tanks at densities of 50, 100, 150 or 200 shrimps m^?2 for 12 weeks of growth. Salinity averaged <1.0 g L^?1 for each growth study. The different treatments resulted in significant differences in both the final body weight and the survival rate (SR). Shrimp acclimated for 100 h showed substantially improved survival (83%) relative to shrimp acclimated for shorter periods. Shrimp yields for all cultured periods ranged from 0.32 kg m^?2 in tanks stocked at 50 m^?2 to 1.14 kg m^?2 in tanks stocked at 200 m^?2. We conclude that whiteleg shrimp can be successfully grown in low‐salinity well water, and that the growth, production output and SRs are significantly higher when shrimp are acclimated for longer periods.     

Variability of the total free amino acid (TFAA) pool in Mytilus galloprovincialis cultured on a raft system. Effect of body size

Variability of total free amino acid (TFAA) pool in Mytilus galloprovincialis was analysed following raft culture of growing mussels. With the aim to ensure the actual effect of animal’s size, a mussel population was sampled in laboratory covering the field size (15‐ to 60‐mm shell length). TFAA showed a constant profile regardless size increase of individuals in both field and laboratory experiments. Environmental salinity and temperature varied within a relatively narrow range in the field (34–35 g L^?1 and 14–19 °C, respectively). Despite the narrow variability of TFAA, significant differences were reported for the most representative amino acids. Specifically, taurine content significantly dropped with soft tissues increase in both field and laboratory experiments. Up to 40% of taurine drop in growing individuals was counterbalanced by the increase in alanine as main protein free amino acid (PFAA), whereas glycine showed high variability and inconsistency. PFAA increased linearly with the endogenous condition of individuals and were inversely correlated with protein content. In summary, TFAA pool of M. galloprovincialis remained unchanged with animal’s size, which might ensure optimal protein turnover rates during growth and establish a significant link between energetic status (condition) and PFAA, values that are equilibrated by a significant drop of the most abundant taurine.     

Growth in adult gilthead sea bream (Sparus aurata L) as a result of interference in sexual maturation by different photoperiod regimes

Gilthead sea bream (Sparus aurata L) pass through the period of sexual maturation while being intensively reared for commercial purposes. This process affects growth and food conversion efficiency. In an attempt to reduce this problem several lighting regimes have been utilized which impede gonad development by increasing the length of the day. A four hour increase in natural day length three months before reaching sexual maturation in fish of 390 g, improves growth in comparison to the control by about 15% (means SD of 606.2 ± 10.6 and 526.5 ± 12.7 g, respectively) towards the end of the natural reproductive season. However, these differences are subsequently compensated since the sexual maturation process is only delayed (rather than being permanently halted). The manipulated groups reached maturity and then stopped growing between three and four months after the control groups. For this reason, it would appear advantageous to manipulate sexual maturation through photoperiod alteration in those groups which go to market either during or towards the end of the reproductive season since greater fish weights will be achieved in addition to an improved food efficiency.     

Growth performance,survival, feed utilization and nutrient utilization of African catfish (Clarias gariepinus) larvae co‐fed Artemia and a micro‐diet containing freshwater atyid shrimp (Caridina nilotica) during weaning

Problems of limited number of dry feeds as supplement or replacement of live feeds have led to poor larval nutrition in many species of fish. Therefore, the suitability of co‐feeding 8‐day‐old African catfish (Clarias gariepinus) posthatch larvae using live feed (Artemia salina) and formulated dry diet containing freshwater atyid shrimp (Caridina nilotica) during weaning was investigated. The experiment ended after 21 days of culture and respective groups compared on the basis of growth performance, survival, feed utilization and nutrient utilization. Larvae co‐fed using 50%Artemia and 50% formulated dry diet resulted in significantly (P < 0.05) better growth performance, food gain ratio (FGR), protein efficiency ratio (PER) and productive protein values (PPV) than other treatments. The lowest growth performance occurred in larvae weaned using 100% formulated and commercial dry diets. Better survival of over 90% was obtained in larvae weaned using 50%Artemia and 50% dry diet, while abrupt weaning using 100% dry diets resulted in lower survival (<75%). These results support a recommendation of co‐feeding C. gariepinus larvae using a formulated dry diet containing C. nilotica and 50% live feed when weaning is performed after 8 days posthatching period.     

Effects of diludine supplementation on growth performance,liver antioxidant enzyme activities and muscular trace elements of rainbow trout (Oncorhynchus mykiss) juveniles at a low water temperature

Diludine is used as an effective agent reducing mutagenic effects of environmental pollutants, increasing productivity and protecting reproductive system of parental individuals and quality of their offspring. A 10‐week study was conducted to evaluate potential effects of diludine on rainbow trout (Oncorhynchus mykiss) juveniles growth performance, feed utilization, survival rate, liver antioxidant enzyme activities (superoxide dismutase, SOD, EC1.15.1.1 ; catalase, CAT, EC1.11.1.16 ; glutathione peroxidase, GPx, EC 1.11.1.9 ; glutathione reductase, GR, EC1.6.4.2 ; glucose‐6‐phosphate dehydrogenase, G6PD, EC1.1.1.49 and glutathione S‐transferase, GST, EC1.5.1.18 ), the levels of malondialdehyde (MDA) as a lipid peroxidation marker and muscular trace elements at a low water temperature (9 °C). Diludine was added at 0.2, 0.5 and 1 g kg^?1 to a fish meal–based control diet, and each diet was fed to triplicate groups of rainbow trout juveniles. After 10 weeks, there were no differences in survival rate between fish fed experimental diets (P > 0.05). It was observed that a significant improvability existed for both growth and feed utilization in fish fed diets supplemented with diludine (P < 0.05). Antioxidant enzymes showed significantly increased activity in liver tissues (P < 0.05) and then a decrease to initial activity levels during the experimental time. (GPx activity was not determined in the juvenile livers.) SOD and GST activities in liver of fish fed the diets with diludine tended to be higher and GR activity tended to be lower than that in fish fed the basal diet. However, in general, it was determined that different concentration of diludine did not affect the studied antioxidant enzyme activities except G6PD in the liver of juveniles fed the diet with 1 g kg^?1 diludine. On the other hand, the significant reduction was found in MDA levels in the fish fed the diets with diludine compared with basal diet on the 14th and 28th days of experiment. It was also observed that Cu, Fe, Mg, Zn and Se levels were significantly higher in the juveniles fed the diet with 1 g kg^?1 diludine than those fed the basal diet. In conclusion, the results of this trial indicate that 1 g kg^?1 dietary supplementation with diludine seems to be most positive for rainbow trout production in cold‐water adaptation.