ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractTo overcome the lability of vitamin C (L‐ascorbic acid or L‐AsA), an essential nutrient of shrimp diets, the efficacy of Mg‐L‐ascorbyl‐2‐phosphate (MAP), a relatively stable derivative of L‐AsA, was examined.Groups of juvenilePenaeus japonicuswere fed five different test diets containing different amounts of MAP for 100 days, to determine if MAP could be utilized by shrimp. Normal growth was observed on test groups fed diets containing 1,078, 430 and 215 mg MAP per kg, whereas mass mortality occurred in populations fed diets containing 43 and 0 mg MAP per kg. The dead shrimp found in the latter two treatments exhibited blackened lesions underneath the exoskeleton. The symptom looked similar to what was reported in previous papers as L‐AsA deficiency syndrome. The feeding experiment suggests that MAP can be utilized byP.japonicusas a suitable replacement for L‐AsA, and a supplement of 215 to 430 mg in 1 kg is sufficient to prevent clinical signs of vitamin C deficiency.Repeated measurements of remaining L‐AsA and MAP, made after diet processing and storage, demonstrated that MAP was significantly more stable than L‐AsA and was less prone to

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractInfections of the virusBaculovirus penaei(BP) have historically impacted penaeid shrimp production in both hatcheries and ponds. BP causes cytopathological alterations and mortality in at least four species, includingPenueus vannamei. This study established experimental infections with BP in laboratory‐rearedP. vannamei. The most useful protocol involved BP infection in third substage protozoea (P3) induced by feeding virus‐contaminated material to rotifers and, in turn, feeding those rotifers to the shrimp larva. Infections were also established by delivering virus‐containing brine shrimp to mysis (M) and postlarval (PL) stages. When virus originating from infected adults and juveniles was fed to P3's, the shrimp exhibited patent infections with hypertrophic nuclei, polyhedra, free virions, and occluded virions five or six days after being fed the virus. In contrast, when the source of virus material was from bioassay larvae rather than from adults and juveniles, similar patent infections developed in P3's by one to two days. A significant mortality in the resulting M's and PL's was associated with the infections with short but not long prepatent periods. In experimentally infected shrimp, examination by light microscopy and transmission electron microscopy revealed extensive viral infection in many cells in the anterior midgut and as many as 80–90% of the proximal and medial hepatopancreatic tubular cells. Free and occluded virions capable of producing disease ruptured into the gut lumen soon after infections became patent. Tests conducted in 1 L Imhoff cones, 160 L spat‐cones, and aquaria all produced infections, usually with a prevalence of 100%. The system provides a useful method to detect and assay for infective agents, to amass infective material for research purposes, and to assess the biology of and host response to the virus under different c

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe lack of approved drugs and chemicals needed to manage disease and pests in culture systems is the major constraint facing the penaeid shrimp culture industry in the United States. The industry needs the timely approval of the therapeutants for disease control for cost effectiveness and public safety. The approval process for the needed chemotherapeutants (drugs, parasiticides, disinfectants, and water quality agents) is administered by the US. Food and Drug Administration (FDA) and the US. Environmental Protection Agency (EPA). Both FDA and EPA have procedures for registration of compounds for minor use whereby needed approvals may be obtained at far less cost than is typical for uses in major agricultural industries.Aquatrine® is the only compound with specific approval for use in shrimp culture. Three others—formalin, oxytetracycline, and trifluralin—have entered the approval process. Because of human safety concerns, replacements are needed for malachite green, chloramphenicol, and the nitrofurans. Candidates for replacing these compounds include trifluralin, oxolinic acid, nalidixic acid, the potentiated sulfonamides, erythromycin, and oxytetracycline. A need exists for an environmentally safe and effective agent to treat fusarium disease.The U.S. Department of Agriculture Interregional Research Project Number 4 (IR‐4), in conjunction with FDA, has begun addressing the problems of the aquaculture industry. Thus, the penaeid shrimp industry has an excellent opportunity to obtain the approvals of chemotherapeutants that are needed for continued growth toward a full potential in this c

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAfter preliminary six week experiments showed that shrimp pond effluent from an intensive culture growout pond had the capacity to nearly double shrimp growth in laboratory tanks, an 18 day experiment was designed to determine if similar results occurred in the presence of high quality feeds. The results presented here corroborate the hypothesis that autochthonous factors in shrimp pond water stimulate shrimp growth. These results revealed that performance of currently available shrimp feeds is greatly improved in the presence of pond effluent, regardless of feed quality. Increased feed performance did not appear to be an artifact of supplemental feed availability in pond effluent. The implications from these experiments are that, even in intensive culture systems (above 40 shrimp per m2), in‐situ sources of nutrition play an important role in shrimp growt

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00780.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractInduction of ovarian maturation inPenaeus vannamei, by implantation of ganglion prepared from female lobster,Homarus americanus, with developing ovaries was investigated under tank culture conditions. Four of six females with thoracic ganglion implants were maturing while only two of thirteen females of the control groups with abdominal ganglion or no implant matured. Two ripe stage V were found 18 days after implantation of lobster's thoracic ganglion. This indicates that ovarian maturation ofP. vannumeiin tanks can be induced and accelerated by implantation of thoracic ganglion prepared from maturing females of another species. Ovarian maturation may be induced by a gonad‐stimulating hormone, secreted by the thoracic ganglion of maturing females. This gonnd‐stimdating hormone is not species specific in activity in the shrimp and lobs

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00781.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThree intensive growout trials usingPenaeus vunnumeiwere conducted in round ponds in Hawaii in 1987. A 337 m2experimental pond was stocked at 100 shrimp/m2for two trials; a 2,000 m2commercial prototype pond was stocked at 75/m2for one trial.In the experimental pond trials, shrimp survival averaged 88 ± 10% (SE) and feed conversion averaged 2.2 ± 0.2. Growth averaged 1.5 ± 0.3 g/week, yielding 18.2 ± 1.7 gram shrimp in 80 ± 5.5 days. Combined production in the experimental trials was 32,272 kg/ha in 174 days (from stocking of trial 1 to harvest of trial 2). Comparing these results to 1986 results (Wyban and Sweeney 1988), it was concluded that shrimp growth is not affected and production is doubled by increasing stocking density from 45/m2to 100/m2.Pooling data from 1986 and 1987, a significant linear regression was obtained when weekly growth of shrimp above four grams individual size was regressed on mean weekly pond temperature: growth = 0.37 * temperature ‐ 8.44, (r2= 0.41;P<0.01). Multiple regression to examine effects of shrimp size, pond biomass, and shrimp age on the temperature‐growth relationship was not significant.In the commercial prototype pond trial, survival was 67% and feed conversion was 2.0. Growth averaged 1.4 g/week, yielding 18.1 gram shrimp in 88 days. Production was 9,120 kg/ha. Individual shrimp size distribution at harvest in the commercial pond was similar to experimental pond results, indicating that shrimp growth in the two systems was comparable.Financial characteristics of a hypothetical 24 pond shrimp farm using these results were determined using an electronic spreadsheet model (hung and Rowland 1987). Feed costs were 40% of total operating costs while postlarvae and labor were 14% and 16% of total operating costs, respectively. Breakeven price (BEP) was far more sensitive to changes in revenuedetermining inputs such as survival and growth than to comparable changes in costdetermining inputs such as feed and postlarvae costs.Together these results suggest that commercial scale round pond production mimics experimental scale production and that round pond technology has commercial p

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00782.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractExperiments on the intensive cultivation of Pacific white shrimp,Penueus vunnumei, in ponds in South Carolina were begun in 1985 at the Waddell Mariculture Center. A preliminary study involved two 0.1 ha ponds stocked at an average of 43 postlarvae/m2, with management practices based on those used in Taiwan for intensive pond culture ofPenueus monodon. Harvest yields averaged 6,757 kg/ha for one crop, demonstrating the technical feasibility of such intensive culture of P.vannumei. In 1986, 2.5 ha of ponds at the Waddell Center (six ponds totaling 2.0 ha at 40 postlarvae/m2and two totaling 0.5 ha at 60/m2) yielded a total of 13,606 kg (5,442 ke/hn). These results were obtained even though aeration and water exchange rates were substanthlly reduced and South Carolina experienced its worst heat wave and drought. This served as a pilot‐sde, proof‐ofconcept test. Tank studies in 1985 and 1986 showed little effect of stocking density on shrimp growth rate at densities of 20–100 animals/m2. This was confirmed in ponds in 1987 when no differences in growth rates were observed at densities of 20–100 postlarvae/m2. Harvest biomass increased directly with stocking density in all trials, reaching a maximum of 12,680 kg/ha/crop at 100 shrimp/m2in 1987.Initial attempts to intensify production in the nascent South Carolina shrimp farming industry occurred in 1986, when approximately 32 ha of private ponds were stocked at densities of 10–32 postlarvae/m2. Farm harvests increased with stocking density, with maximum yield of 3,656 kg/ ha/crop. This trend toward intensification in the private sector is continuing, and in 1987 maximum harvests from private ponds were 5,050 kg/ha from a 0.3 ha pond and 4,625 kg/ha from a 1.5 ha pond. Prospects for further implementation of intensive culture in the private sector appear excellent, with yields of ≥ 10,000 kg/ha/crop expected from private farms within the nex

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00783.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractPenueus monodonhas become almost synonymous with aquaculture in Taiwan, indicating the level of commercial success it has attained over the past two decades. However, other species are being considered for future culture to diversify an industry overly dependent on one product, as well as to provide the market with an alternative commodity. This paper explores the feasibility ofP. penicillatusas an alternative culture species in Taiwan.P. penicillatushas seven merits that make it ideal for aquaculture: 1)P. penicillatusis comparatively resistant to low temperature. 2) It is a medium sized “white prawn” and is attractive to the consumer. 3) The migration behavior shows good possibilities for culture in sea water. 4) Wild spawners are abundant and natural, and induced spawning in captivity is relatively easy. 5) Larvae spontaneously spawned in captivity show good survival, existing on the natural food present in the pond. 6) It has a low protein requirement and has good growth in the early stages even at high stocking densities of 100–120 prawns/m2. 7)P. penicillutusgrows to a comparatively uniform size. This paper also discusses some difficulties in the culture of this

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00784.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractGrowth performance data onPenaeus semisulcatusunder semi‐intensive pond culture conditions were collected in Israel between 1985 and 1987. In 1985, shrimp growth, from PL to 21.5 g, was accomplished in separate nursery and grow‐out phases. Pond production during the grow‐out phase was 3,000 and 3,943 kg/ha, and mean weight was 21.5 g. Shipments to Europe revealed a need to produce larger shrimp to maximize revenues. Any increase in individual shrimp weight at harvest would require new management practices. Juvenile shrimp (3.4 to 6.3 g) were held during the winter of 1986 in open ponds and restocked in grow‐out ponds in the spring of 1987. Shrimp survival during overwintering was 12 and 15%. A maximum mean shrimp weight of 25.6 g and a maximum pond production of 7,451 kg/ha were obtained in 1987 using this strategy. It is possible that comparable pond production results and shrimp weight, but with higher overall shrimp survival, could be obtained by headstarting shrimp in greenhouses. Two major problems that need to be solved before commercial shrimp culture can succeed in Israel are the formulation of a locally produced feed and the out‐of‐season induced maturation and spawning ofP. s

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1988.tb00785.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY