Further observations on the co-cultivation method for isolating infectious pancreatic necrosis virus from asymptomatic carrier rainbow trout, Salmo gairdneri Richardson     

C. AGIUS  A. RICHARDSON  W. WALKER 《Journal of fish diseases》1983,6(5):477-480

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Development of a feeding strategy for silver perch, Bidyanus bidyanus (Mitchell), based on restricted rations   总被引：1，自引：0，他引：1  

Stuart J Rowland  Geoff L Allan  Charlie Mifsud  Mark Nixon  Peter Boyd  & David Glendenning 《Aquaculture Research》2005,36(14):1429-1441

To develop a feeding strategy for the Australian freshwater fish silver perch (Bidyanus bidyanus Mitchell), a series of eight experiments was done in 1 m³ cages in an aerated, earthen pond to determine the effects of feeding rate (% body weight) and feeding frequency (no. of feeds day^?1) on the growth and feed conversion ratio (FCR) of fingerlings and larger fish under ambient water temperatures over the range 13.8–30.6°C. Fish were fed extruded pellets of a silver perch diet containing 34% digestible protein and 14 MJ kg^?1 digestible energy. Commercial silver perch farmers were consulted about feeding practices for large fish (>500 g) and at water temperatures below 12°C, and winter feeding practices for other warmwater species were used to complete the strategy. In the feeding experiments, growth and FCR increased with increasing feeding rates to a level above which only FCR increased. Optimal feeding rates and frequencies were those which resulted in maximal growth, while minimizing effort (feeding frequency) and FCR. The highest feeding frequency required for maximal growth, including that of small fingerlings was twice (2 ×) daily, and the optimal feeding rates varied with water temperature and size of fish. The optimal daily regimes were: small fingerlings (initial mean weight, 2.0 g) 7.5% 2 × at a mean temperature of 23.3°C; fingerlings (14.9–27.7 g) 7.5% 2 × at 27.1°C, 5.0% 2 × at 23.7°C and 2.0% 1 × at 16.8°C; and large silver perch (162.5–510.6 g) 0.5% 1 × daily or 1.0% on alternate days at 15.6°C, 1.0% 1 × at 17.3°C, 3.0% 2 × at 24.1°C and 2.0% 2 × at 27.9°C. It is suggested that regimes of 0.5% 1 × daily for fingerlings (<50 g) and 0.5% 1 × on alternate days for larger fish are used at temperatures of 9–12°C, and 0.5% 3 days week^?1 and 0.5% 1 day week^?1 for fingerlings and larger fish, respectively, at 6–9°C. Feed inputs should not exceed 150 kg ha^?1 day^?1 in ponds less than 0.3 ha and 100 kg ha^?1 day^?1 in larger ponds. Our research has established a feeding strategy for silver perch based on restricted rations.  相似文献   

Biography: Ken Wolf     

Charlie E. Smith  Joe McCraren 《Journal of fish diseases》1989,12(5):401-403

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Performance of rainbow trout and Snake River cutthroat trout reared in oxygen-supersaturated water     

Donald A. Edsall  Charlie E. Smith 《Aquaculture (Amsterdam, Netherlands)》1990,90(3-4):251-259

Rainbow trout, Oncorhynchus mykiss, reared in water containing oxygen at 180% or 94% of saturation for 125 days showed no difference in growth or feed conversion. Hematocrits were nominally reduced in fish held in the supersaturated oxygen environment, but increased within 35 days of returning the fish to water at 94% oxygen saturation. Mortality was not affected. Hemoglobin levels did not differ statistically between treatments by the end of the trial. Cutthroat trout, O. clarki, reared in 183%, 127% or 97% oxygen-supersaturated water for 91 days also showed no differences in growth or feed conversion. Hematocrits decreased nominally as dissolved oxygen was increased. There were no differences in mortality during handling or distribution stress tests. Results of these trials indicated that long-term culture in water saturated up to 183% oxygen has no adverse effect on growth or survival of these two species.  相似文献   

Comparison of the Hydrological Budgets and Detailed Hydrological Responses in Two Forested Catchments   总被引：1，自引：0，他引：1  

MILLER  J. D.; ANDERSON  H. A.; FERRIER  R. C.; WALKER  T. A. B. 《Forestry》1990,63(3):251-269

Detailed hydrological budgets for two mature forested catchmentsshow very similar inputs and vegetational throughputs (throughfalland stemflow) for both Norway and Sitka spruce. Stream outflow,equivalent to 1707 mm, is comparable both with measured rainfallinputs (2250 mm) or rainfall in combination with throughfalland stemflow (1826 mm). Soil throughflow from the differingsoil profiles follows similar patterns, in both soil types withinitial flow response at depth (>50 cm). This may increasetowards a maximum for some horizons, and, depending on inputamounts, be followed by a transfer of flow up through the profile.Hydrological responses and their effect on soil temperatureswere again similar at both sites, with no obvious anomalieswhich would explain the resultant differences in stream chemistrybetween these catchments. The observed changes in surface waterchemistry must therefore be primarily due to vegetational orsoil induced chemical processes combined with observed differencesin hydrological fluxes.  相似文献   

Metabolic differences between hepatic parenchymal cells and a cultured cell line from liver     

PERSKE WF  PARKS RE  WALKER DL 《Science (New York, N.Y.)》1957,125(3261):1290-1291

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