摘要:

AbstractThere is a significant body of legislation affecting veterinary medicines, including those intended for use in fish. However, the main criteria for authorization remain quality, efficacy and safety. Safety for humans, both operators and consumers, is of paramount importance in the assessment process. Consumer safety is largely addressed through the maximum residue limit (MRL) approach with withdrawal periods being established to ensure that the MRL is not exceeded? Residues monitoring plays an important role in ensuring that withdrawal periods are observed and that illegal drugs are not used.

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.00782.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAnadromous Arctic charr,Salvelinus alpinus(L.), from the River Halselva in Finnmark, northern Norway, were used as broodstock for the production of smolts. During the smolting period the fish were either shielded from normal working routines, subjected to normal work routines, or exposed to excessive work routines (stress) within the hatchery. None of the handling routines affected the gill‐Na‐K‐ATPase activity, or the hypoosmoregulatory capacity of the charr. Compared with normal handling, neither stress nor shielding caused any significant difference in the migratory behaviour of the charr, in the duration of the sea residence, or in homing success. However, the stressed group did show a lymphocytopenia at end of the rearing p

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.00787.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractGrowth in terms of shoot dry weight was studied in five species of mangroves, namelyAvicennia marina, A. officinalis, Ceriops decandra, Rhizophora apicuhtaandR. mucronata,raised in shrimp pond‐derived effluent. The effluent had significant negative effect over diluted effluents on shoot dry weight inR. apiculataandC. decandra,but not in the other three species, in general, the effluent, when diluted by 70%, improved the shoot biomass production of mangrove seedling

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.t01-1-00788.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

abstractTo examine the impact of fouling organisms on the growth and survival of the scallopEuvola ziczacL., we maintained 31‐34‐mm juveniles in pearl nets at 8 m in depth at Turpialito, Golfo de Cariaco, Venezuela. The experiment ran for a 67‐d period under four conditions: (1) shells and nets cleaned; (2) shells not cleaned and nets cleaned; (3) shells cleaned and nets not cleaned; and (4) shells and nets not cleaned. The growth of the scallop was least when fouling developed on both the pearl nets and scallop shells. The rate of growth of the shell (height and mass) was strongly affected by organisms colonizing the pearl nets and only weakly affected by organisms colonizing the shells. Fouling organisms on the shells only slightly affected rates of increase of tissue mass, but probably accounted for increased mortality. In developing commercial culture ofE. ziczac,strategies need to be developed to limit the adverse effects of fouling on

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.t01-1-00790.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe objective of this study was to assess the efficacy and mode of action of 2‐phenoxyethanol as an anaesthetic for two size classes of goldfish,Carassius auratus(L.), at three different temperatures. Goldfish (2.15 ± 0.05 g, and 9.19 ± 0.17 g) were exposed to 0.3, 0.4 and 0.5 ml 2‐phenoxyethanol l1at 20, 25, and 30oC. Time needed to induce anaesthesia was dependent on concentration and water temperature. At temperatures at and below 25oC, 0.4 ml l1was needed to induce total loss of equilibrium within less than 15 min. Above 25oC, 0.5 ml l1was required to induce anaesthesia. Recovery rate was independent of the length of anaesthesia, which indicates that the anaesthetic is taken up and lost via a concentration gradient at the gill membrane and skin/solution interface. Fish recovered within less than 10 min after they had been taken out of the anaesthetic solution. In a second experiment, goldfish responded to a repeated exposure to 2‐phenoxyethanol daily over a period of 14 days with increased tolerance, which indicates a habituation response to the anaesthetic. The use of 2‐phenoxyethanol as an anaesthetic both for short‐term anaesthesia and for anaesthesia under transport conditions i

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.t01-1-00791.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractJuveniles of gilthead sea bream,Sparus auratusL., with individual weight 1.92 g, were reared under salinities of 8, 18, 28 and 38%o. The transfer to lower salinities (8‐28%o) was abrupt. The results showed that better daily growth rates and food conversion efficiencies (FCE) when growing at 28%o gave the best performance. Statistically, salinity values above 28%o do not significantly affect daily growth rates and daily voluntary food intake. Maintenance requirement decreases linearly with increasing salinity. In particular, a l%o decrease of salinity is associated with a 0.014 (% body weight day‐1) increase of daily maintenance requirement. Mortality rates are high at salinities of 8 and 38%o (65% and 20% respectively) and minimal (1‐3%) for fish reared under intermediate salinities (18‐28%o). Finally, scope for growth, expressed as the minimum difference between food amount eaten and food attributed to growth, is better when the fish are kept at a salinity of 28%o. This means that most of the food amount eaten is attributed to growth and food wastage is minimal. These results confirm that gilthead sea bream fry show best performance when reared at a salinity

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.t01-1-00792.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIncrease in shrimp farming was stimulated by growth in world market for high‐value shrimp products in the 1980s. The major cultured shrimp producers are located in Asia‐Pacific and Latin American regions. The revealed comparative advantage (RCA) method is used to provide insights into the export performance of nine selected shrimp producers in the Japan and United States markets, separately. Shrimp is marketed in a wide variety of product forms, and prices vary according to various product attributes including species, size, taste, quality and origin. The results show that vertical product differentiation concerning different varieties of a good in terms of both quality and price plays an important role on the relative export competition of shrimp products among major shrimp‐exporting countries. As a result of the geographical advantage, Asia‐Pacific producers enjoy comparative advantage in the Japanese imported shrimp market. Joint ventures with the United States provide great benefits to Ecuador and Mexico in exporting fresh shrimp into the United States

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.t01-1-00794.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractFour clonal lines of ayu,Plecoglossus altivelisTemminck&Schlegel, were produced through gynogenesis, mixed before hatching and reared communally. After 10 months, a randomly taken sample was subjected to a standardized shallow‐water stressor. Haematocrit, haemoglobin, red blood cells count (RBC) and mean corpuscular volume (MCV) were obtained from stressed and non‐stressed fish. DNA fingerprinting was used to confirm the clonal nature of the organisms and to identify the clonal line to which each fish belonged.We observed significant differences between clonal lines mostly in the haematocrit and MCV measured under no‐stress conditions. Such differences are suggested to represent mainly genetic variance, on account of the common environment provided to all the experimental groups.The stress response ratio was lower than expected, mainly due to some unexpectedly high non‐stress values.Heritability values (h2) were medium to high for the no‐stress measurements (mean 0.238) and very low or zero for the stressed groups’traits (excepting one high value of 0.484).We conclude that the use of communally reared clonal lines represents a good tool for the characterization of the physiological traits, thus allowing for their utilization as genetic selecti

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.00804.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractOver a 56‐day feeding period, during which juvenile African catfish,Clarias gariepinus(Burchell) increased in body weight at least threefold, diets containing fresh or rancid oils (0.352 and 9.133 mmol MDA equivalents per g oil, respectively) at two levels of supplemental vitamin E (20 or 100 mgall‐rac‐α‐tocopheryl acetate kg‐1dry diet) were fed at 3% body weight per day. On termination of the feeding trial, growth performance and food utilization were assessed. Additionally, health criteria such as hepatosomatic index (HSI), haematocrit, plasma haemoglobin and plasma α‐tocopherol concentration were determined. Plasma α‐tocopherol was seen to increase significantly (P<0.05) concomitant with dietary dose of the vitamin. Oxidation of dietary lipid source was observed to cause significant depletion (P<0.05) of α‐tocopherol from the plasma pool on consumption of the rancid test‐diets. Final body weights of the catfish revealed that vitamin E supplementation in rancid diets significantly improved growth (P0.05). Values of other growth parameters and nutrient utilization indices were seen to respond positively to increased vitamin E levels and fresher dietary oils. With respect to other health indices, HSI was strongly correlated (P<0.05) to dietary vitamin E dose and not oil oxidation state, with catfish fed lower α‐tocopherol doses exhibiting larger livers proportional to somatic mass. Haematocrit values were significantly (P<0.05) lower in fish fed low‐tocopherol/fresh‐oil diets. Although no measurably significant differences were found between treatments with respect to plasma‐haemoglobin concentration, higher mean values for the fish fed rancid oils at the lower α‐tocopherol inclusion level may indicate heightened Spontaneous haemolysis in this group. Mechanisms to account for dietary modulation of health indices in catfish under the present dietary regime are postulated. It was concluded that supplemental α‐tocopheryl acetate in diets likely to undergo oxidation, would protect catfish from the nutritional stress imposed by rancid oils and increase growth above levels associated

ISSN:1355-557X    

DOI:10.1046/j.1365-2109.1996.t01-1-00814.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY