摘要:

Abstract.Aeromonas salmonicidassp,salmonicidais shown to produce several extracellular proteins having gelatinolytic activity. Among the six isolates tested, two (NCMB 1102 and 84–14–R) produced both high (89–100 kDa) and low molecular (37 kDa) weight gelatinases, while the other four demonstrated only the 89–100 kDa forms. The low molecular form (metalloprotease 1: MP 1, 37 kDa) was isolated by ammonium sulphate precipitation, hydrophobic, ion exchange and size exclusion chromatography. The isolated enzyme was inhibited by the metal‐chelating agents o‐phenantroline and EDTA, and by excess Zn ions, and thus was defined as a metalloprotease. Its pH‐optimum was 7–5, optimal activity was at 40°C and its pI 5.2. Specificity studies demonstrated cleavage of gelatin and azocoll

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00305.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Oxygen consumption of juvenile rainbow trout (5 g at 13°C) at moderate swimming speeds did not change significantly when infected withCryptobia salmositica.However, significant reductions of as much as 44% of the maximum aerobic scope for activity and 24% of the critical swimming speed were observed when the parasitaemia reached a maximum of 57.6 × 106ml−1fish blood at 3 weeks post‐ infection. Blood haematocrit was significantly reduced from the initial 34.1 to 19.7% at 4 weeks post‐ infection, probably as a result of haemolysis by the parasite. The destruction of red blood cells clearly led to lower oxygen carrying capacity, and reduced respiratory and swimming perf

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00306.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Treatment of rainbow trout macrophages with glycyrrhizin (GL), an aqueous extract of licorice,Glycyrrhiza glabra, enhanced their respiratory burst activity. Maximal effects were seen using concentrations of 10–100 μml−1. GL also modulated trout lymphocytes, increasing proliferation responses to the mitogen phytohaemagglutinin some two‐fold over a range of GL concentrations. In addition, GL elicited the release of a macrophage activating factor (MAF) from head kidney leucocytes, as assessed by the ability of generated supernatants to increase respiratory burst activity of target macrophages. MAF activity was most apparent using 100 μg ml−1GL to induce MAF release and a 48‐h incubation period with the target macrophages. Finally, GL was shown to enhance the release of MAF in response to the mitogen concanavalin A. The possible use of GL as a stimulant of fish innate defences i

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00307.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Parr of Atlantic salmon,Salmo salarL., were fed semi‐purified diets supplemented with 60 mg astaxanthin kg−1and without astaxanthin supplementation for 10.5 months. The astaxanthin concentration in the non‐supplemented diet was analysed to be 6–0 mg kg−1The growth of the fish was significantly affected by the dietary treatment. The mean daily weight gain in the groups fed the supplemented diets was 0.39% throughout the period, whereas the groups fed the non‐supplemented diet had a mean daily weight gain of 0.18%. The dry matter and fat content were significantly higher in fish fed the supplemented diet. The astaxanthin concentration in the muscle of fish fed the astaxanthin‐supplemented diet was 2–7 mg kg−1versus 0–3 mg kg−1in the non‐supplemented fish. Antioxidant vitamins in the muscle (retinol, α‐tocopherol) and liver (retinol, α‐tocopherol and ascorbic acid) were two to 20 times higher in the fish in the supplemented group, suggesting antioxidant sparing effects. Blood haemoglobin and immunological parameters tended to be higher in fish fed the low astaxanthin diet although the difference was not significant. However, the resistance to challenge withAeromonas salmonicidawas higher in fish fed the astaxanthin supplemented diet. This may be due to a difference in weight at the time of the challenge which, in turn, may have influenced the body composition and smoltification of the fish. A relationship between dietary astaxanthin concentration and antioxidant status in both liver and muscle was observed, and this may also have had an influence on the observed differences in blood para

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00308.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Cryptocaryon irritans(Ciliophora), isolated from the reef fish,Grammistes sexlineatusThumberg, was established as primary infections in mullet,Chelon labrosus(Risso). Only a small percentage (200 trophonts per gram of host. A close temporal association between host death and trophont exit was found, possibly as a result of epidermal disruption leading to dysfunction of osmoregulatory and respiratory syst

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00309.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.A digoxigenin‐labelled DNA probe was used forin situdetection of thePenaeus monodon‐type baculovirus (MBV) derived from cloned MBV polyhedrin genome in culturedPenaeus monodonFabricius. First, the specificity of the probe against MBV DNA with dot blot hybridization analysis was verified. This probe indicated that cloned MBV polyhedrin fragment can be used as an MBV‐specific probe. This was then used to microscopically examine sections of MBV‐infected tissues for a blue‐purple precipitate indicative of a positive reaction for MBV. MBV‐positive cells were located only in the epithelium of the hepatopancreatic tubules and of the midgut. Furthermore, comparison of the susceptibility to MBV infection among several life‐stages of the shrimp showed that the MBV genome was found in the zoea, mysis, post‐larva, and adult stages, whereas MBV DNA was not detected in either eggs or nauplii. The results were quantified fromin situhybridization with an image analyser to compare the degree of cell infection among groups of culturedP. monodoncollected from various

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00310.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.The aim of the present study was to compare the effect of high and low doses of different vitamin C formulations on the course of ichthyophthiriosis (Ichthyophthirius multifiliisinfection) in rainbow trout. After a depletion period, trout fingerlings were fed diets deficient in vitamin C(AA 0), or containing different levels of silicone coated ascorbic acid (AA; 50/200 mg kg feed−1) or ascorbyl phosphate (AP; 50/2000 mg AA equivalent kg feed−1). Fish infected withI. multifiliisdemonstrated a significant reduction in mortality when fed high levels of AA or AP. A correlation between the parasite burden and the vitamin C content in the diet was not found. Specific immunity—measured as immobilization litre of sera—was not influenced by the level or the formulation of vitamin C in the diet. The most probable mechanism of high level doses of vitamin C is an increase of the general health status expressed as an improved nonspecific resistance and ability to cope with different stressors. In rainbow trout infected withI. multifiliis, the beneficial effect of ascorbyl phosphate is equal to that of silicone coated ascorbic acid, and therefore, the more stable AP may be a valuable alternative for use in fis

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00311.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00312.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00313.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00314.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY