摘要:

Evidence is presented of lethal blood clot formation in fishes. A variety of factors commonly encountered under aquacultural conditions may generate such clots.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03682.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The relationships of ovary weight, liver weight and visceral lipid stores to body weight in the goldfish were examined at different times of the year. Both arithmetic and logarithmic relationships were examined. Ovary weight significantly increased relative to increasing body weight in goldfish and the exact nature of this relationship changed from month to month. However, larger fish were found to have proportionately larger ovaries than small fish at specific times of the year. Regression lines for liver weight versus body weight were also determined. Monthly differences were found in the liver weight‐body weight relationship. Visceral lipid stores expressed per gram of protein were found to be independent of body weight. Lipid stores expressed in this manner peaked in February while ovary weight peaked in April. The consequences of compensating for body size when expressing organ (liver, ovary) sizes, such as hepatosomatic index and gonosomatic index, are discusse

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03683.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

When the tench (Tinca tincaL.) was exposed to a slight increase, 8.5 mg/l, in the potassium content of the water, metabolic and hormonal changes occurred which lasted more than four weeks. An initial phase of lipolysis was followed by a partial consumption of glycogen reserves, which in turn was followed by a phase of gluconeogenesis. Hyperglycaemia persisted throughout the experiment. The ion distribution in erythrocytes and liver changed relatively early; there was no observable change in water content. These changes are similar to those observed during the osmoregulation of fish.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03684.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Natural‘antibodies’are substances found in the blood of animals that have not been immunised against infective agents. However, exposure to these agents or to cross‐reacting antigens may well have taken place. Fish contain naturally‐occurring, relatively nonspecific, lectin‐like proteins or glycoproteins, which are distinct from immunoglobulins, and which react with a wide variety of antigens and may confer some degree of immunity against natural infection. In most cases the cause of the antigenic stimulus is not obvious although the formation of these‘antibodies’may have been brought about by exposure to various micro‐organisms. Many of these antibody‐like molecules behave in a similar manner to immune antibodies or immunoglobulins and cross‐react with specific carbohydrate moieties on the cell walls of bacteria, erythrocytes and certain other cellular antigens, due to the presence of similar antigenic determinants.It is difficult to ascribe an appropriate definition to the term‘natural antibody’. In fish, these‘antibodies’have been so designated on the basis of functional rather than structural criteria. Such naturally‐occurring, low grade, antibody‐like‘immune’substances include‘acute phase’proteins, lysozyme and chitinase, interferon, agglutinins, lysins, complement and properdin, precipitins, and non‐immunoglobulin, lectin‐like molecules. In addition to the above non‐immunoglobulin materials, natural immunoglobulins identifiable as IgM have also been reported in fish. Furthermore, mucus contains many biochemical agents capable of reaction against infective organisms and thus providing the host with an immediate or a first line of defence mechanism.This review compiles some of the relevant information in the literature concerned with natural‘immune’substances, present in the serum and mucus of fish, involved in protection against pathogens. Wherever possible the basic physicochemical properties of these substances are indicated and the

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03685.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Noradrenaline induced vasodilation in isolated perfused eel or trout gills was inhibited by propranolol, aβ‐adrenergic blocking agent. The noradrenaline effect was much reduced in gills of fish which had been kept in 1 mg/l solutions of the detergent LAS (linear alkylate sulphonate; 12C chain length). LAS produced concentration‐dependent vasodilation, which was inhibited by propranolol, in eel and trout gills. Noradrenaline produced additional vasodilation in eel and trout gills which had been dilated by 2.10−8mLAS but had no effect on trout gills perfused with 2.10−7mLAS. Gills from trout which had been kept in 0.1 mg l‐1LAS responded to noradrenaline normally but the propranolol inhibition appeared to be p

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03686.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Otolith accretion was greatest in summer when opaque bands were laid down and slowest in winter when hyaline rings were formed. Food intake was minimal in winter and maximal in summer. Liver weight was high in summer and winter and low in spring after spawning. Growth in length was higher in summer than winter. Gonad weight was greatest in winter for both sexes. Spawning occurred from February to April. After spawning males recovered earlier than females and testes ripened earlier than the ovaries. From winter to summer, the sea temperature increased from 7.5–13.0°C; the day length from 7–17h; and the salinity varied from 34.07−

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03687.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Experiments were performed to investigate the influences of dietary protein on fecundity in the guppy,Poecilia reticulata. No significant differences in total body length and standard length were found between females given food with different protein levels. A significantly higher total body weight was found both in females fed on 47% and 31% protein compared with females given 15% protein. The frequencies of females with only intrafollicular embryos or with only ova or both embryos and ova in the ovary were not significantly different between populations given different protein amounts. There was a significantly lower frequency of females without embryos and ova but with previtellogenic oocytes in the group given highest protein (47%) compared with the group fed on 31%. Significantly higher values of ovarian length, width and gonad weight were found among females given 47% protein compared with females fed on 15% protein. The ovarian height was significantly higher only in females given the highest protein amount when compared with the group fed on 31% protein. No significant difference of ovarian volume was found between groups given different protein contents. The average gonadosomatic ratio was highest in the groups fed on 47% protein. Significant correlations were found between gonad weight and total body weight of females in each group. Ovarian volume versus total body weight as well as versus gonad weight also yielded significant correlations in all groups. No significant differences of fecundity were found either between females given 47% and 31% protein or between females fed on 47% and 15% protein. A somewhat higher number of ova per individual fish was, however, observed among females given 31% when compared with females fed on 15% protein. The ovum size remained the same between groups given different protein contents. No significant correlation was found between fecundity and ovum diameter in the groups.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03688.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The incidence and intensity of infection of various ages and conditions of migratory trout byEubothrium crassumare described. A marine source of the worm seems likely and explanations for the characteristics of the parasite burden are given on this assumption. Within weeks of first going to sea the hosts accumulate large numbers of the parasite. One year suffices for the life cycle of Eubothrium but growth continues for at least two years and possibly for longer. The parasite burden decreases in older fish because of the stress imposed on the parasite by successive migrations of the host to and from fresh water and because older fish tend to feed earlier in the year.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03689.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The spawning migration of brook lampreys (Lampetra planeri, Bloch) was investigated in a South Swedish lake and stream system for two consecutive years. The nightly variations were analysed by a multiple regression technique. In one of the seasons, characterized by frequent rain storms, water level was the most important factor explaining 60% of the observed variation in migration. In the following year, when the migration period was unusually dry, temperature and on‐shore winds at the mouth of the stream were the most influential environmental variables explaining 50% of the observed changes in behaviour. When data were combined for the two years only temperature showed a significant influence. The critical temperature for the onset of migration was estimated to be 7.5°C. Size distributions and sex ratios of the migrating lampreys, which are semelparous, indicated that the age distribution was complex and that females were older than males. Migration was essentially nocturnal, but late in the season day migration was also observed. A marking experiment resulted in few recaptures probably because of high predation and/or orientation difficulti

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb03690.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY