Quantitative seasonal changes in the protein, lipid and energy content of the carcass, ovaries and liver of adult female plaice, Pleuronectes platessa L.

Abstract

A detailed study was made of the seasonal changes in energy reserves in adult female plaice, Pleuronectes platessa L. The weights of lipid, protein, glycogen and ash in the carcass, liver and ovaries were measured in females approximately 35 cm long on ten occasions during one year. These data were converted to data for a ' real ' growing female by using a growth curve to take account of increasing length during the year. Growth of the whole body and of the body components was assumed to be isometric.Plaice show a marked seasonal cycle of body weight and energy content. A six year old female plaice of 330 g, 32.6 cm long and with an energy content of 406 kcal in May, assimilates 560 kcal before December when it ceases to feed. Of this, 234 kcal is used to produce eggs, I59 kcal is used for metabolism during starvation, and the remainder 167 kcal, is used in growth. There is an increase in length to 35.9 cm and in weight to 462 g over the year. From December until March, when plaice do not feed but grow large ovaries, 40% of the protein in the body is utilised, 33% is devoted to egg production and 7% is metabolised to provide energy; 64% of the lipid is used, only 14% being used for egg production but 50% is metabolised for energy. Lipid supplies 75% of the energy for metabolism and so forms the major reserve; 42% of the energy assimilated during the year is devoted to reproduction. The main source of lipid and protein reserves is the carcass.

Comparative study of body composition of different fish species from brackish water pond

“…These bottles were then put in an oven at 40 to 50 o C to evaporate the solvent leaving the lipid fraction. Total protein in dry mass was calculated by the difference method from the mass of other main constituents like ash, lipid and water (Caulton and Bursell, 1977;Dawson and Grimm, 1980;Salam and Davies, 1994;Dempson, et al, 2004). Carbohydrates do not form a major component of fish and thus are generally neglected due to their negligible amounts (Elliott 1976, Caulton and Bursell, 1977, Salam and Davies, 1994.…”

“…Protein content, which is important component, tends to vary little in healthy fish (Weatherly and Gills, 1987). There is a wealth of literature available on body composition of various fish species (Berg, et al, 2000, Dawson and Grimm, 1980, Dempson, et al, 2004, Grayton and Beamish, 1997Jobling, 1980, Jonsson andJonsson, 1998;Salam and Davies, 1994;Shearer, 1984;Weatherley and Gill, 1987). However, little is known about the growth of fish found in brackish water in Pakistan.…”

Comparative study of body composition of four fish species in relation to pond depth

“…These bottles were then put in an oven at 40 to 50 o C to evaporate the solvent leaving the lipid fraction. Total protein in dry mass was calculated by the difference method from the mass of other main (Caulton and Bursell 1977;Dawson and Grimm 1980;Salam and Davies 1994;Dempson et al, 2004). Carbohydrates do not form a major component of fish and thus are generally neglected due to their negligible amounts (Elliott 1976;Caulton and Bursell 1977;Salam and Davies 1994).…”

Annual changes in the nutritive state of North Sea dab

“…Although the authors did not cover the entire seasonal cycle, glycogen values in late summer were distinctly higher than concentrations in autumn and winter. Seasonal changes of the glycogen concentrations in the livers of plaice P. platessa (Dawson & Grimm, 1980) were of the same order of magnitude in dab. However, unlike dab, the highest relative amounts were found in May.…”

“…The significance of the liver as principal storage organ for lipids is supported by the relatively low lipid concentrations in the muscle tissue which could also serve as a lipid store (Dawson & Grimm, 1980). Identical extraction-methods were applied to both tissues and therefore a direct comparison is possible.…”