Some physiological consequences of keepingMytilus edulis in the laboratory
TL;DR: The ratio oxygen consumed to nitrogen excreted declines in all experiments, indicating an increased use of protein as an energy substrate, and the values for this ratio suggest that M. edulis is able to maintain and continue maturation of the gametes in spite of this considerable utilisation of general body reserves.
Abstract: 1. Nutritive and temperature stresses in experiments cause a decline in general body condition and dry weight ofMytilus edulis L. Carbohydrate and protein are lost from the body; these losses are greater from the germinal (mantle) than from the somatic (non-mantle) tissues. There is a more rapid loss of carbohydrate than of protein.M. edulis is able to maintain and continue maturation of the gametes in spite of this considerable utilisation of general body reserves. 2. The greater the degree of stress imposed on the test animals the greater is the utilisation of carbohydrate and protein. However, the mussels maintain a balance between these two components so that, at any one time, the carbohydrate to protein ratio does not differ between individuals subjected to different degrees of stress. 3. During the cultures there was a decline in oxygen consumption. Nitrogen excretion either increases or slightly decreases. The ratio oxygen consumed to nitrogen excreted declines in all experiments, indicating an increased use of protein as an energy substrate. The greater the degree of stress imposed upon the test animal, the greater the rate of decline of the O:N ratio. The values for this ratio suggest thatM. edulis normally utilises carbohydrate or fat substrates, though proteins may also be utilised in response to stress. 4. Indices of physiological condition should prove useful in determining the degrees of stress that are experienced by lamellibranchs under cultivation. In order to measure the effects of stress, knowledge of the normal seasonal variations in physiological indices is needed, to serve as a “base-line” with which induced changes in condition may be compared.
Citations
More filters
TL;DR: The dynamic indices reviewed are based on production estimates, and hence reflect physiological changes over specified time intervals, and only net growth efficiency is recommended for use in bivalve aquaculture, and it is applicable to all life stages.
438 citations
01 Jan 1983
TL;DR: Developmental and seasonal metabolic activities in marine mollusks are a reflection of the complex interactions between food availability, temperature, growth, and reproductive activities and it seems unlikely that there will be a significant contribution from anaerobic metabolism in bivalve larvae.
Abstract: Publisher Summary This chapter discusses developmental and seasonal metabolic activities in marine mollusks. Developmental and seasonal metabolic cycles are a reflection of the complex interactions between food availability, temperature, growth, and reproductive activities. The effects of temperature on the energy balance of marine invertebrates have been recently reviewed. Most of the attention has been on the energy reserves in the eggs and on the larval stages of commercial species for which spawning and rearing techniques were developed in the laboratory. The development of small-scale analytical techniques has made it possible to determine accurately the levels of protein, lipid, and carbohydrate in small numbers of larvae. Carbohydrate reserves seem to be unimportant in the metabolism of marine larvae. This is not the case, however, in the terrestrial and fresh-water snails Helix pomatia and Limnaea stagnalis in which galactogen forms an important energy reserve for the developing embryo. Complete oxidation of lipids can only take place aerobically but proteins can be metabolized by both aerobic and anaerobic pathways. However, with a high available oxidative capacity, it seems unlikely that there will be a significant contribution from anaerobic metabolism in bivalve larvae. The maintenance of aerobic metabolism provides a greater yield of ATP for energy-requiring processes than anaerobic metabolism.
309 citations
TL;DR: In this paper, the authors investigated the effect of oxygen consumption, filtration rate and assimilation efficiency on the acclimation of Mytilus edulis L to high and low temperature under laboratory conditions.
Abstract: Mytilus edulis L is shown to acclimate to high and low temperature under laboratory conditions The warm and cold acclimation of oxygen consumption, filtration rate and assimilation efficiency are described for groups of animals maintained at three food-cell concentrations Complete acclimation (Precht's type 2) of oxygen consumption and filtration rate occur within 14 days There is no change in assimilation efficiency within the 28-day experimental period The results are integrated and discussed in the context of a simple energy budget In terms of the energy budget there exists a marked contrast between warm and cold acclimation An “index of energy balance” is proposed in order to assess the state of the energy balance When animals are fed above the maintenance requirement the energy budget remains in an equilibrium state during cold acclimation, whereas the acclimation to a warm temperature regime disrupts the balance and represents a physiological stress During warm acclimation, prior to the re-establishment of an energy equilibrium the blood sugar level increases, suggesting that the animal is required to mobilize and utilize its energy reserves
300 citations
TL;DR: Gabbott et al. as mentioned in this paper showed that temperature and nutritive stress resulted in a decline in body condition of mussels, Mytilus edulis, when kept in the laboratory.
Abstract: In a previous paper Bayne & Thompson (1970) showed that temperature and nutritive stress resulted in a decline in body condition of mussels, Mytilus edulis, when kept in the laboratory. Both carbohydrate and protein were lost from the body tissues but the losses (as a percentage of the initial values) were greater from the germinal (mantle) than from the somatic (non-mantle) tissues. In spite of the loss of body reserves, M. edulis was able to continue maturation of the gonad during the autumn to spring period. In the early summer, however, when the gametes were fully ripe, stress resulted in a recession of the gonad and a rapid loss of protein from the mantle tissues. A similar decline in condition index and loss of glycogen and protein has been reported for adult oysters, Ostrea edulis, when maintained under hatchery conditions (Gabbott & Walker, 1971).
285 citations
References
More filters
TL;DR: The rate of growth of Mytilus larvae increased with increased temperature from 10–18° C, but from 13–13° C the growth was relatively temperature-independent, and at temperatures higher than 18° C larvae from a littoral area grew at a slightly increased rate, but larvae from an sub-littoran area showed decline of the growth rate.
Abstract: Techniques for the induction of spawning of Mytilus edulis, the delay of spawning and the rearing of the larvae are described. The rate of growth of Mytilus larvae increased with increased temperature from 10–18° C, but from 13–18° C the growth was relatively temperature-independent. At temperatures higher than 18° C larvae from a littoral area grew at a slightly increased rate, but larvae from a sub-littoral area showed decline of the growth rate. There was a decline in the rate of growth during the life of a larvae at all temperatures. Cleavage and early development occurred from 8–18° C and increased with increased temperature. Isochrysis galbana and Monochrysis lutheri were good foods for Mytilus larvae. Growth rate increased with mcreased cell concentration to 100 cells Isochrvsis/µ litre and 2.0 µ litre packed cell volume of Monochrysis/litre. A mixture of these 2 species supported more rapid growth than either species indivldually. Larvae fed with Nannochloris atomus and Chlorella sp. grew...
492 citations
483 citations
TL;DR: During 1946 and 1947, regular samples of Mytilus edulis from a number of localities on the British coasts, including Conway, Brancaster and Liverpool, were examined for gonad condition and spawning, and the criteria employed in distinguishing the stages of gonad development are described.
Abstract: During 1946 and 1947, regular samples of Mytilus edulis from a number of localities ontheBritish coasts, including Conway, Brancaster and Liverpool, were examined for gonad conditionand spawning. For each sample, the mean stage of gonad development was computed. The criteria employed in distinguishing the stages of gonad development are described.Ripening of the gonads takes place within a few weeks of the onset of spawning, in general commencing when the sea temperature has risen above 7–0° C. There appears to be no correlation between nutritional condition and ripening of the gonads, or subsequent spawning.In all localities and in each year in which observations were made spawning occurred in late spring (mid-April to the end of May) and in most areas lasted for a short period only (2–4 weeks). At Brixham, in 1949 and 1950, the duration of the spawning period was longer (4-6 weeks). In most cases, 70–80% of the mature population spawned during the first 7–10 days of the breeding period. No evidence of periodic spawning was obtained.In all cases, spawning commenced in a period during which the mean temperature to which the mussels were exposed was rising from c. 9–5° C. to 11–12–5° C. In most cases, the onset of spawning was coincident with a period of spring tides, and of predominantly bright sunny weather. The initial rate of spawning appears to be directly related to the rate of increase in mean temperature to which the mussels are exposed.After spawning, mussels enter into a ‘neuter’ or ‘resting spent’ stage in which all traces of sexuality are lost.
161 citations
TL;DR: In this paper, the authors describe the renal histology of molluscan kidney, including the Renopericardial duct, pericards, and branchial heart appendage.
Abstract: kidney . . . . . . 2 (I) Monoplacophorans . . 2 (2) Polyplacophorans . . 2 (3) Aplacophorans . . . 3 (4) Gastropods . . . . 3 ( 5 ) Lamellibranchs . . . 5 (6) Scaphopods . . . 5 (7) Cephalopods . . . 5 IV. Renal histology . . . . 7 (I) Renopericardial duct . . 7 (2) Pericardial glands . . 8 (3) The kidney sac . . . 8 (4) Branchial heart appendage . 12 V. Urine formation . . . . 12 (I) Site of ultrafiltration . . 13 (2) Evidence for ultrafiltration . 14 (3) Rate of filtration . . . 14 (4) Composition of initial urine . 15 111. Morphology of the molluscan VI. Secretion and resorption . . (I) Resorption of inorganic ions. (2) Site of ion resorption in the kidney . . . . (3) Resorption of organic substances . . . . (4) Secretion: general . . ( 5 ) Inorganic ions . . . (6) Organic compounds . . VII. Excretion of dyes . . . . VIII. Excretionofnitrogenouscompounds (I) General remarks . . . (2) Ammonia . . . . (3) Urea . . . . . (4) Uric acid . . . . ( 5 ) Purines . . . . (6) Free amino acids . . (7) Other nitrogenous compounds . . . . IX. Discussion . . . . . X. Summary . . . . . XI. References . . . . . XII. Addendum . . . . . 17 '7
159 citations