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1.
The use of the Chilean oyster. Tiostrea chilensis (Philippi. 1845), for aquaculture has been hampered by difficulty in obtaining commercial quantities of larvae due to the low fertility of the existing broodstock of this species taken from well-known populations in Chile and the South Island of New Zealand. The larval productions of two wild populations of this oyster in northern New Zealand were assessed as potential alternative sources of broodstock for aquaculture. The study found both populations produced larvae from young, small oysters, and that a much larger proportion of the population was brooding larvae each year than has been reported elsewhere. The mean fertility of one of these populations, at 71 056 ± 3701 (SE) larvae per oyster, was the highest reported for any population of this species. The significantly higher fertility of these populations makes them well suited for further development as broodstock for aquaculture. 相似文献
2.
A.G. Jeffs 《Aquaculture International》1999,7(3):189-199
International interest in the commercial aquaculture of the Chilean oyster, Tiostrea chilensis, is frustrated by an inability to artificially control their unusual breeding behaviour. The manipulation of breeding in this oyster will rely on a better understanding of its gametogenic cycle. Consequently, the gametogenesis of a wild population of highly fertile Chilean oysters from northern New Zealand was studied over three years to assess the potential for artificially controlling oyster breeding for aquaculture. The population was mostly comprised of simultaneous hermaphrodite oysters that generally followed annual cycles of gametogenesis. Oysters spawned as males throughout each year with increased spawning from November to February (ie., austral spring and summer). Ova were abundant throughout the year, although female spawning increased during spring. The unpredictable spawning of ova among individual oysters and the strong possibility of self-fertilization create difficulties for the development of controlled breeding in this species. If the full aquaculture potential of T. chilensis is to be realized, further research should be directed at identifying the factors involved in controlling female maturation, spawning and fertilization. 相似文献
3.
Matthew J. Slater Malwenn Lassudrie Andrew G. Jeffs 《Journal of the World Aquaculture Society》2011,42(5):714-725
Effective nursery diets can greatly reduce the cost of producing juvenile sea cucumbers for release to aquaculture or restocking programs. However, methods for systematically testing the bioavailability of artificial diet ingredients for sea cucumbers are poorly developed, and consequently, there has been little research in this field. The current study presents methods developed to test the suitability of common carbohydrate and protein sources for inclusion in artificial diets for juvenile Australostichopus mollis. Apparent digestibility of carbohydrates was moderate and did not exceed 50% for any carbohydrates assayed. Wheat starch and carrageenans showed the highest digestibility amongst carbohydrates. Differences in apparent digestibility were not reflected in growth performance of juvenile A. mollis fed carbohydrate diets; overall growth performance was poor for all diets. Artificial protein sources consistently exhibited higher apparent digestibility, ranging from 75.1% for fish meal to 98.1% for casein. Low‐cost protein sources, like meat meal, show promise for future use in artificial diet formulation. However, delivering high protein content may reduce ingestion rates and thereby lower overall digestive efficiency in juveniles. Results show that artificial carbohydrate sources have some potential as diet constituents for juvenile sea cucumbers but are unsuitable as primary energy sources. Future testing of artificial carbohydrate sources for A. mollis may require predigestion to improve digestibility. 相似文献
4.
Lipid and fatty acid composition of likely zooplankton prey of spiny lobster (Jasus edwardsii) phyllosomas 
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下载免费PDF全文 Several of the world's major spiny lobster fisheries, including Jasus edwardsii in Australasia, have gone into dramatic decline due to decreasing recruitment of their lecithotrophic postlarvae. There is evidence that the decline is related to poor nutritional condition of the postlarvae, especially lipid that is accumulated in large quantities during the preceding pelagic larval stage. Therefore, characterizing the lipid composition of the likely potential zooplankton prey of the larvae (phyllosomas) of spiny lobsters will provide new insights into their nutritional requirements. The lipid class and fatty acid composition of more than 30 species of likely zooplankton prey of the larvae of the spiny lobster, J. edwardsii, were determined. These results showed that most zooplankton prey had a high proportion of their lipid content as polar lipid (PL) (range of 9.4–94.8%, mean of 76.1 ± 2.6%). Zooplankton prey provide phyllosomas with polyunsaturated fatty acids (PUFA) for growth and development, as well as a range of other important fatty acids that are accumulated as PL and used for fuelling the migration of the subsequent lecithotrophic postlarvae across the continental shelf. Overall, these results indicate that phyllosomas consume prey with wide ranging lipid content, but dominated by PL, and high in docosahexaenoic acid, eicosapentaenoic acid and the key fatty acids used for energy storage. 相似文献
5.
Both E. coli and S. aureus were simultaneously injected into the left renal arteries of 55 female dogs. The arteries were occluded for 10 minutes prior to the injection and 10 minutes after. The renal veins were occluded during the injection and for 10 minutes after.
Ten animals did not survive longer than 24 hours. Ten of 45 developed neither renal lesions nor bacteriuria; of the remaining 35 which did, five were killed on each of the second, seventh and fourteenth days, and their renal lesions were assessed. Eighteen of the remaining 2 which developed bacteriuria were killed 3 to 12 weeks following surgery when bacteria could no longer be recovered from the urine. Only two dogs had persistent bacteriuria 12 weeks after surgery. All animals which developed bacteriuria had gross lesions in the left kidney but not the right.
Naturally occurring renal lesions were found in 17 of 78 random-source dogs at laparotomy. E. coli was cultured from the urine of five of these dogs but not from the kidneys. These lesions were morphologically similar to experimental ones.
It is concluded that with this method renal lesions similar to spontaneous ones can be produced, but care must be taken to exclude the relatively large percentage of random-source dogs with naturally occurring lesions from any study.
Various forms of infectious nephritis have been reported to be among the commonest diseases of dogs (1, 2). The successful production of chronic pyelonephritis in dogs depends on a variety of factors in addition to injecting bacteria into either the renal artery or ureter. Thus, ureteral obstruction, renal anoxia and reduced pulse pressure increased the susceptibility to renal infection (3, 4, 6, 7, 8).
Our laboratory has been concerned with the production of experimental pyelonephritis in dogs so that the efficacy of various treatments could be studied. The present work was undertaken to standardize methods of producing the disease and to compare experimental renal lesions with naturally occurring ones.
相似文献6.
New or improved routes are used to prepare all the nineteen methylbenzyl chrysanthemates, including 2,4,6-trimethylbenzyl (+) and (?)-trans-chrysanthemates, 2,3,4,6-tetramethyl-and 2,3,4,5,6-pentamethyl-benzyl chrysanthemates, and the chrysanthemates of the new alcohols, 2,3,5-and 3,4,5-trimethylbenzyl alcohols. 相似文献
7.
D. C. Griffiths K. A. Jeffs G. C. Scott R. Gair E. Lester F. E. Maskell J. H. Williams 《Pest management science》1972,3(5):609-618
When seeds of winter wheat were carefully dressed in the laboratory with combinations of fungicides (organomercury alone or organomercury plus the systemic fungicide carboxin) and insecticides (aldrin, carbophenothion or chlorfenvinphos as liquid formulations, or a γ-BHC powder formulation) so as to ensure that nearly all the recommended amounts of the active ingredients stuck to them, the insecticides gave good insect control, but γ-BHC with organomercury fungicide decreased the number of plants that germinated, and γ-BHC with carboxin and organomercury was even more damaging. Commercially dressed seeds had only about 30 to 60% of the target dose of fungicides, but more than 80% of the target doses of the liquid insecticides aldrin, carbophenothion and chlorfenvinphos. With combinations of powder fungicide and liquid insecticide, greater amounts of pesticide on the seed were obtained if the insecticide was put on first. Because of unusually late sowings and little fungal infestation, neither laboratory nor commercially treated seeds provided good tests for control of smut. 相似文献
8.
There is intense international interest in the development of spiny lobster aquaculture and of particular interest is the development of artificial diets for spiny lobsters. However, there is little information on the feeding behaviour of spiny lobsters and their ability to handle and consume artificial feeds of different dimensions. Observations of the feeding behaviour of juveniles of the spiny lobster Jasus edwardsii in culture found that they waste significant amounts of food through externally fragmenting the feed pellets before sweeping particles into the mouth. The consumption efficiency of different sized pellets was found to change markedly with increasing size of the juvenile lobsters. Up to 50% of artificial food was wasted by the inefficient feeding behaviour of the lobsters. However, consumption of the feed could be reduced by as much as 19% by altering pellet size. These results indicate that the size of feed pellets, and their consistency and fragmentation characteristics, will be critical aspects of cost‐effective feeding of cultured spiny lobsters. 相似文献
9.
Evaluation of the formulated diet MySpat for feeding hatchery‐reared spat of the green‐lipped mussel,Perna canaliculus (Gmelin, 1791) 下载免费PDF全文
下载免费PDF全文 Yue Gui Leonardo Zamora Brendon John Dunphy Andrew Greig Jeffs 《Aquaculture Research》2016,47(12):3907-3912
As with most bivalves, a high cost component of hatchery and nursery culture of the green‐lipped mussel (Perna canaliculus) is the raising of live micro‐algae feeds. To remedy this, artificial feeds have been developed, however, these have had mixed success for this species. In this experiment, we tested the formulated diet MySpat (sourced from INVE Aquaculture) on P. canaliculus spat of approximately 1 mm in size. Performance measures under study were mussel spat growth and survivorship after 21 days feeding on varying proportions of MySpat. The experimental diets tested, consisted of a mix of T‐Isochrysis galbana, Pavlova lutheri and Tetraselmis suecica micro‐algae that were replaced with increasing proportions of MySpat, i.e. 25%, 50%, 67%, 75%, 90% and 100% MySpat replacement. Our results revealed no significant increase in spat mortality with increasing MySpat diet levels, and growth was equivalent to the micro‐algae only dietary control in all diets except the 90% and 100% MySpat replacement diets. Such results highlight the role MySpat could have for P. canaliculus hatchery operations, particularly with regard to reducing the costs of raising micro‐algae when producing seed for industry. A greater understanding of the particle selection process of this species would be beneficial for future studies seeking to employ artificial diets. 相似文献
10.
Assessment of the production and dispersal of faecal waste from the sea‐cage aquaculture of spiny lobsters 下载免费PDF全文
下载免费PDF全文 Despite the rapid expansion of spiny lobster aquaculture, very little is known about its potential environmental impacts. In an effort to understand the potential impacts of sea‐cage culture of spiny lobsters, the faecal output and settling velocity of faeces of spiny lobster were quantified. These data were then used in hydrodynamic modelling to assess the dispersal pattern of faecal material from two sizes of hypothetical spiny lobster farms, so that inferences about likely benthic impacts could be made by modelling different scenarios of farm stocking density and food conversion efficiency. The overall mean settling velocity of lobster faecal strands was 0.9 ± 0.05 cm s?1. There was a positive correlation between both the weight and density of faecal strands and their settling velocity. Conversely, neither the length nor the surface area of faecal strands was correlated with the settling velocity. Hydrodynamic modelling showed that faecal material deposition mainly occurred directly beneath the sea‐cages. The density of faecal material deposition increased proportionately with higher stocking density and FCR values. Overall, the results indicate that the deposition of faecal waste from sea‐cage lobster aquaculture is unlikely to cause widespread benthic impacts when operating to the current highest commercial stocking and feeding levels. 相似文献