摘要:

AbstractTwo growth trials were conducted to evaluate the nutritional quality of several soybean products as constituents in diets for the gilthead sea bream,Sparus aurata(L.). In a preliminary experiment, the fish were fed six diets containing different levels of solvent extracted soybean meal as a replacement for white fishmeal at four substitution levels: 10, 20, 30 and 40% of the fishmeal protein component. The diets supported less growth as the inclusion of soybean meal increased. However, significant reductions in growth were apparent at the 30% substitution level. All growth parameters followed the same trend. In the second experiment, six diets with 35% of the total protein contributed from differently processed soybean meals were tested. The products included three industrial full‐fat meals heat processed for different periods, a solvent extracted meal and a soya protein concentrate. Protein digestibility coefficients were measured for all the experimental diets. All growth parameters of the fish fed the underheated full‐fat meal, solvent extracted meal and soya concentrate were significantly lower than the control group. Protein digestibility coefficients were similar with no statistical differences (P<0.

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00979.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe effects of four different doses of organic (cowdung) and inorganic fertilizers (single super phosphate: SSP) in combination were studied on plankton production, species diversity and fish biomass in saline and freshwater fish ponds. Physico‐chemical factors of pond waters were also monitored. Alkalinity and nutrients increased with increase in the dose of fertilizers. Dissolved oxygen (DO) also remained sufficiently high up to the third treatment; however, levels declined significantly in the ponds receiving the fourth treatment (20 000 kg ha‐1year‐1of cowdung and 3000 kg ha‐1year‐1of SSP). The highest plankton population, species diversity and higher fish biomass was also observed in ponds which received the third dose of fertilizers (10 000 kg ha‐1year‐1of cowdung and 1500 kg ha‐1year‐1of SSP). However, a decline in these parameters was observed in ponds which received the highest (fourth treatment) dose of fertilizers. Nutrients remained slightly lower in brackish‐water fish ponds. When species diversity values were compared, it was observed that, although values werte higher in freshwater ponds, their abundance (no. 11) remained lower than in brackish‐water fish ponds. Similarly, fish biomass also remained significantly higher in brackish‐water ponds than in freshwater ponds. From these studies, it can be concluded that a combination of 10 000 kg of cowdung + 1500 kg ha‐1year‐1of SSP app

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00980.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA 12 week feeding trial was conducted in a closed recirculating system with Cichlasoma synspilum (Hubbs) fry (280 mg) in order to determine their protein requirements. Six diets containing increasing protein levels (30, 35, 40, 45, 50 and 55%) were formulated using brown fish meal as the protein source. The fish were fed by hand daily at a rate of 6% body weight: at 2‐week intervals, the fish were bulkweighed and the feeding rate was adjusted accordingly After 90 days, a direct relationship was observed between dietary protein content and fmal body weight, weight gain, and specific growth rate (P<0,05), with the best results for diets containing 50,45,40 and 55% of protein: feed intake, food conversion ratio, protein efficiency ratio, carcass nitrogen deposition and apparent N utilization were also statistically higher (P<0,05) for fish fed diets with 50, 45, 40 and 55% of protein content. The lower performance was obtained in those fish fed diets with 30 and 35% protein content. Applying the broken‐line response method with SGR data, the protein requirement of C. sytispilum fry was established as 40.

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00981.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIn this study, a short‐term storage of pre‐activated eggs of the Japanese ornamental (koi) carp,Cyprinus carpioL., at three different temperature regimes is reported. Koi eggs were stored at low temperatures (6‐9oC), at variable or high temperatures (12‐31C) and at moderate‐stable temperatures (20‐24.5oC). Survival of the developing embryos was examined at the first and the second day post‐activation, and in hatch‐out larvae. Survival was calculated for each treatment by linear regression Y = a‐bX (P± 0.01), except for eggs incubated at temperature of about 20 C(P>0.1).The specific mortality index (b/a 100), as a ratio between the mortality rate (b) and the fertilization rate (a), indicated that the highest mortality is associated with the high and unstable storage temperatures, while the lowest mortality is with the moderate and stable storage temperatures. Eggs can be stored at moderate and stable temperatures for a maximal duration of 6h, yielding survival of hatch‐out larvae higher than 50%. In two trials, fertilization potency of sperm stored in a domestic refrigerator (5‐9oC) for 5h, was compared with freshly stripped sperm and no differences in fertilization rates were found betw

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00982.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe value of computerized information retrieval systems in quantifying the effect of disease, identifying risk factors involved with specific diseases and enabling the effectiveness of disease control strategies to be accurately assessed are well recognized in agricultural production. This paper outlines the establishment of such a system for farmed Atlantic salmon,Salmo salarL., in Ireland. The database currently holds information from 13 million fish from 11 sites over a 5‐year period (34 years of production). Analysis of variance indicated that differences between sites were more significant than those between years. In relation to pancreas disease (PD), analysis of mortality data from two sites over a year in which both sites suffered an outbreak of PD supported the hypothesis that PD is primarily caused by an infectious agen

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00983.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAustralian bass, Macquaria novemacideata (Steindachner),mature but do not spawn in fresh or brackish water ponds. Ovulation and spawning of captive (n = 158)and wild Australian bass (n = 123) was induced in the normal breeding season by single injections of human chorionic gonadotropin (hCG). Doses of 100‐4000IU kg‐“ hCG induced ovulation and the optimum dosage was 500 IU kg” hCG. The breeding season was from mid‐May to late August for wild fish,and extended into September for captive fish. There was a tendency for mean fertilization and hatching success to decline over the breeding season. Greater fertilization and hatching success was obtained from fish which spawned naturally than from stripped fish. Fish spawned after 34,2 ± 0.4 h (mean ± SE, n = 74). Ovulating fish that failed to spawn were stripped after 40.2 ± 0.3 h (n = 76). The timing of stripping and fertilization was an important factor determining hatching success. There was no apparent difference in latency periods or the number of eggs spawned between captive and wild fish. However, the mean number of eggs obtained from naturally spawned fish was higher than for stripped fish. The techniques described in this paper will assist the largescale production of Australian bass by increasing the quality and quantity of larvae from hCG‐ind

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00984.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractWhen reared in captivity, first‐generation hatchery‐reared Arctic charr,Salvelinus alpinus(L.), from Møkkeland lake, northern Norway, differed from wild‐caught conspecifics from the same source. Incidence of caudal fin damage (used as an indirect assessment of aggressive interactions) was high amongst the wild‐caught charr, and there was considerable mortality amongst these fish. By contrast, hatchery‐reared fish displayed little evidence of fin damage, and mortalities were low. When the charr were held in mixed groups of wild‐caught and hatchery‐reared fish, the hatchery‐reared fish showed the most extensive caudal fin damage. Weight losses and decreases in condition were also greatest amongst the hatchery‐reared charr that were exposed to competition with wild fish. The hatchery‐reared charr held together with the wild fish also suffered high mortality. Thus, aggression may have been selectively directed towards hatchery‐reared fish in mixed groups. Taken together, the results suggest that the energetic costs may be high for the re

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00985.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Book review in this article:Spiny Lobster Management. Edited by B. F. Phillips, J. S. Cobb&J. Kittaka.Control of Fish Quality. By J.J. Connell.

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1996.tb00986.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY