ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00055.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTIndirect calorimetry and the chromic oxide indicator method were employed to investigate the digestibility and assimilation of nutrients by cultured lobsters (Homarussp.) growing on experimental diets. Starved and fed lobsters were compared by observing food and oxygen consumption and fecal and urinary excretions in a closed, recirculating metabolic chamber. Apparent digestible and metabolizable energy and nitrogen were determined for 2 diets, which differed in the type and level of protein and carbohydrate. The apparent digestibility of diet 79F, a purified ration containing 46.8% crude protein, was 68.8% on an as‐fed basis, with an apparent digestibility of energy of 88.1%. For diet SM25B, which contained 61.1% crude protein including shrimp meal, apparent digestibility was 66.2% as‐fed and the apparent digestibility of energy was 91.3%. Metabolizable energy values of 4.59 and 4.65 kcal/g dry weight were obtained for diets 79F and SM25B respectively. Growth on the two diets was similar but lobsters fed 79F consumed and excreted significantly more than those fed SM25B. For both diets protein and lipid were better than 90% digested, but the carbohydrate fraction was only about 65% digestible. The apparent higher nutritive value of SM25B for lobsters may be related to protein quality and improved efficiency of utilizat

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00056.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTTwo experiments were conducted to examine the effect of varying amounts of casein and starch relative to the amount of an α‐amylase supplement on shrimp growth and digestive processes. Amylase was supplemented to diets containing 9.5, 19.0 and 28.5% starch in a freeze‐dried nylon‐protein microcapsule form in order to circumvent potential inactivation.After a 30‐day feeding period, shrimp fed diets containing 19.0% and 28.5% starch, and supplemented with approximately 60 IU amylase/g‐dry‐diet were significantly larger (P<0.05) than diets with no amylase or a live short‐necked clam control diet. Shrimp fed 9.0% starch attained a greater mean weight than those fed 28.5% starch. These findings, evaluated collectively, indicate that a 60 IU amylase/g‐dry‐diet supplement was adequate for complete utilization of dietary starch at the 19.0% level but not at the 28.5% level.In a second study which used chromic oxide to examine the effect of an amylase supplement on the digestibility ratio of dietary starch, almost complete digestion (95.7%) was found in the group fed the α‐amylase supplemented diet containing 19.0% starch, as compared to 89.5% digestibility in the group without the amylase supplement.These studies show that up to 30% of the casein in the diet could be substituted with starch on equal weight basis without a substantial reduction in weight gain or feed efficiency, with supplementation of α‐amylase. This may allow future development of m

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00057.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe following experiments compared survival and growth of shrimp larvae fedArtemianauplii beginning at either the protozoea 2, protozoea 3 or mysis 1 substage. Experiment one compared survival and growth of larvalPenaeus setiferus, from the protozoea 2 substage to three‐day‐old postlarvae, fed algae and either freshly hatchedArtemianauplii, decapsulatedArtemiacysts or ultraviolet killedArtemianauplii beginning at the protozoea 2 or mysis 1 substage. Survival was better for those postlarvae fed all threeArtemiafood types beginning at the protozoea 2 rather than the mysis 1 substage. Post‐larval dry weights were similar, regardless ofArtemiafood type or the larval substage at whichArtemiawas introduced.Experiment two compared survival and growth of larvalP. aztecus, from the protozoea 2 substage to two‐day‐old postlarvae, fed algae and liveArtemianauplii beginning at either the protozoea 2, protozoea 3 or mysis 1 substage. Controls were only fed algae. Survival was significantly better for those postlarvae fedArtemiabeginning at the protozoea 2 substage. Post‐larval dry weights increased with the introduction ofArtemianauplii beginning at the protozoea 2 substage. The potential effects of these results on current hatchery procedures ar

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00058.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThis analysis utilized primary data obtained from Texas A&M University Mariculture Research stations to estimate density dependent growth equations for two species of penaeid shrimp,Penaeus stylirostrisandP. vannamei.A simulation model was developed based on these equations, in order to evaluate the effect of alternate stocking densities and cropping schemes on individual weight, total product, gross revenue, total feed consumption, cost of feed and postlarvae, as well as revenue above selected costs (RASC). For each species, an analysis over the growing season of those management schemes yielding the greatest RASC was presented. In addition, the growth equation was re‐estimated based on modified data in order to evaluate sensitivity on RASC. The effect of a 30‐day reduction in the growing season on RASC was also analyzed.P. stylirostrisgrowth was more sensitive to stocking density than that ofP. vannamei.ForP. stylirostris, maximum RASC was obtained by stocking 98,800 individuals/ha. A slightly lower density of 86,450/ha resulted in a negligible decrease in RASC, but may be preferable due to decreased risk. ForP. vannamei, a density of 135,850 shrimp/ha yielded maximum RASC. For both species, production of one crop per year was found to maximize R

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00059.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTRearing ofPenaeus semisulcatushas been conducted by the Shrimp Culture Project since 1970. Hatchery production has improved rapidly since 1980 due to modifications in tank design, live food production, and feeding practices. Since 1972, hatchery tank size has been reduced from 1,600 m3to 400 m3and finally to 15 m3in 1980. Such modifications have increased survival rates from 25% to more than 60% and reduced the quantities of live food required. Studies of various live feeds showed 175 times 103cells ml‐1per day of marine yeast provided the best survival when feeding the protozoeal stages ofP. semisulcatus.An average of 240 rotifers were consumed per larva per day between the first protozoeal and the first mysis stages. For feeding the later mysis stages to the first post‐larval stages, an average of 183.33Artemianauplii per larva was found to be optimal. Of the formulated diets which were obtained from Japan, Sweden, and that produced locally, the Swedish diet proved to be the best. A summary of the current hatchery production is also provi

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00060.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTPond culture ofPenaeus monodonwas undertaken in the Philippines using artificially formulated dry feed and hatchery‐produced post‐larval shrimp. The trial was conducted in two 0.25‐ha managed production ponds with earthen bottoms and concrete dikes. Water depth was 1.1 m; brackish water was used and the salinity ranged from 7 to 17 ppt.For the trial, from 22 June 1982 to 6 October 1982 (106 days), the ponds were stocked at 158,000 postlarvae/ha and produced, respectively, 4,008 kg/ha and 3,808 kg/ha of heads‐on shrimp averaging 31.5 g and 31.3 g in size. Survival in the respective ponds was 80% and 77% with food conversions of 1.69 and 1.78.Based on the costs for postlarvae, feed, labor and power, the shrimp were produced with a positive economic return. The production costs per kilo of whole shrimp produced in each pond were, respectively, US$4.40/kg and $4.63/kg. The entire crop of shrimp was sold heads‐on for an average price of

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00061.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTIntensive aquaculture systems tend to require a large capital investment and be relatively complicated to manufacture or construct with the result that a particular application may be unprofitable or difficult to implement. Raceways have been developed in Kuwait utilizing reinforced plastic liners supported by a wooden railing. Shrimp (Penaeus semisulcatus) were raised in these raceways in order to assess the system. The design allows for easy maintenance, observation and harvest. In addition, the simplicity of the concept assures low material, construction and manpower costs, requiring neither a building contractor nor special tools. A 3.0 m wide raceway of this design costs approximately US$ 17 m‐2in Kuwait. This paper describes the raceway design and construction techniques, and compares the cost with other materials and systems in Kuwait. The results of shrimp rearing trials are discussed with regard to the durability, management and biological compatibility of the desig

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00062.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTPenaeus aztecus, obtained from the wild, and hatchery‐rearedP. stylirostriswere placed together in 65 liter tanks in 5 ratios (0:100, 25: 75, 50:50, 75:25 and 100:0). Two experiments were done. The first experiment consisted of 4 replicates of each ratio at 20°C and 30°C and 2 replicates of each of the 100% tanks at 25°C. Initial size ofP. aztecusandP. stylirostriswere 0.12 and 0.07 g, respectively. In the second experiment initial sizes of the wildP. aztecusand pond‐rearedP. stylirostriswere 1.30 and 0.89 g, respectively. The second experiment consisted of 4 replicates of each ratio at 25°C. The mean weight gain, mortality and biomass (actual and that expected on the basis of monoculture) were calculated.In the first experiment, the 50% treatment had the highest mean weight gain for both species, In both experiments, decreasing numbers ofP. aztecus(increasing numbers ofP. stylirostris) in a treatment resulted in a better growth ofP. aztecusin the treatment. The survival of both species decreased as the percentage ofP. aztecusincreased. Survival was influenced by temperature, density, and species interactions. The largest difference between actual and expected biomass was found to be forP. aztecusat 30°C, notably in the 75%P. aztecustreatment.P. aztecusdoes not seem to be influenced by the presence ofP. stylirostrisas much asP. stylirostrisis influenced byP. aztecusin the s

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1983.tb00063.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY