Seasonal changes in the biochemical composition of the freshwater murrel,Ophicephalus punctatus Bloch

Summary Seasonal variations in various biochemical constituents in the tissues of Ophicephalus punctatus showed that. the fat content in the muscle was highest during November–January and lowest during June–October. Liver contained more fat than the muscle and its seasonal cycle was marked by two well defined peaks. Changes in the ovarian fat were also well defined seasonally. The moisture content in all the tissues varied inversely with the fat. Protein values in different tissues did not show as much fluctuations as fat. In muscle, protein remained high throughout the year except in January. In liver and gonads very low protein values were recorded during the winter months. Seasonal changes in the ash content were not very well marked in any of the three tissues.The seasonal variations in all the biochemical constituents seem related to the feeding intensity of the fish and the maturation of its gonads. Maximum and minimum values of fat fell in accordance with the high and low food intake. In the pre-spawning phase, more fat was stored in the muscle at first but subsequently the fat was mobilized in the liver and finally in the gonads. Peak ripeness was associated with an accumulation of greater protein and fat in the gonads (ovaries). During the spawning months the various constituents were depleted and the post-spawning phase of the fish was marked by minimal values of most of the biochemical constituents, excepting moisture and ash.     

Sexual maturation in the black seabream Mylio macrocephalus Teleostei,Sparidae: changes in pituitary gonadotropes,hepatocytes and related biochemical constituents in liver and serum

Summary The black seabream, Mylio macrocephalus, exhibits the phenomenon of sex segregation. Immature fish are developing hermaphrodites, and show a considerable overlap with mature males in their body weights. Mature females tend to be the heaviest group. Fish can be classified into immature, developing and mature groups, with a further division into definitive males or females in the two latter groups. The developing groups still have bisexual gonads, whereas mature males have testes with only a comparatively inconspicuous portion of ovarian tissue, and mature females possess ovaries with vitellogenic oocytes and a greatly regressed testicular component. In the present study, monthly samples were collected over a 3-year period, and changes in pituitary gonadotropes and liver tissue studied by light, and electron microscopy. Seasonal changes in serum constituents were also studied by biochemical techniques.Gonadotropes increased in number and became hypertrophied during sexual maturation, showing an enhanced cytoplasmic vacuolation and degranulation of alcian blue- and periodic acid-Schiff-positive material. The levels of various biochemical constituents in the liver and serum of developing fish tended to be intermediate between those recorded in the immature and mature groups. In mature fish, the serum levels of glucose, sodium and calcium were elevated, but hepatic glycogen content was less than the developing group, and hepatocytes contained activated mitochondria. The seasonal changes in pituitary cytology, hepatic ultrastructure and serum constituents, could be correlated with the metabolic adaptations to sexual maturation.     

Seasonal variations in RNA–DNA ratios and in indicators of feeding, reproduction, energy storage, and condition in a population of bluegill, Lepomis macrochirus Rafinesque

Liver and epaxial muscle RNA concentrations and RNA-DNA ratios (RNA/DNA) of bluegill Lepomis macrochirus from a central Tennessee lake were maximum in the spring, low during the summer, high again in the fall, and low during the winter. Liver-somatic indexes and DNA concentrations indicated that liver cell volume and energy storage varied seasonally and were lowest during late spring and summer. Seasonal variations in gonosomatic indexes were typical of this species, and RNA/DNA decreased as gonads matured during the spring. RNA/DNA and energy storage in the liver decreased during the major spawning season. Seasonal variations in food consumption may have effected seasonal growth and energy storage. However, a summer depression in RNA/DNA may have been more closely associated with the effects of thermal stratification and dissolved oxygen stress.     

Energy allocation strategy of skipjack tuna Katsuwonus pelamis during their reproductive cycle

The lipid composition of somatic and reproductive tissues was determined for female skipjack tuna Katsuwonus pelamis caught in the western Indian Ocean between latitude 10° N and 20° S and longitude 40° and 70° E. The highest total lipid (TL) contents were in the liver and gonads, with white muscle levels approximately three‐fold lower. Three lipid classes dominated: triacylglycerols (TAG), sterol esters and wax esters (SE‐WE) and phospholipids (PL). Collectively, these accounted for between 70 and 80% of TLs. Changes in lipid concentrations were evaluated over the maturation cycle. Immature fish had the lowest gonad and liver TL levels; concentrations of TL, TAG, SE‐WE and PL accumulated from immature to mature (spawning‐capable) phase, reflecting sustained vitellogenic activity of the liver and a transfer of lipids to developing oocytes from the onset of vitellogenesis. Gonado‐somatic and hepato‐somatic indices were positively correlated with each other and positively related to TL in the gonads and liver. Fulton's condition index and lipid concentrations in muscle did not vary significantly over the maturation cycle; fat content in the main storage tissues was undepleted as the ovary developed. Hence, K. pelamis apparently supports reproduction directly from food intake over the breeding season. In the gonads, reserve lipids (SE‐WE and TAG) and sterols were related to batch fecundity but this was not the case for somatic and hepatic tissues. These results suggest that K. pelamis utilizes an income breeding strategy.     

Seasonal variations in the intermediate metabolism of Parastacus varicosus (Crustacea, Decapoda, Parastacidae)

The aim of this study was to analyze the seasonal variations in the metabolism of Parastacus varicosus and examine the possible relationships to its reproduction. Animals were sampled (9 h to 10 h) in each month in the Gravataí River, RS, Brazil. Haemolymph samples were collected from each crayfish in the field for determination of glucose, total proteins, total lipids, and total cholesterol. Hepatopancreas, abdominal muscle, and gonads were removed for determination of glycogen, total proteins, total lipids, and total cholesterol. ANOVA revealed significant seasonal differences in the biochemical composition of all tissues studied; when the sexes were compared these parameters did not show any significant difference in the hepatopancreas and muscle. However, in haemolymph we observed significant variation only in cholesterol and lipid levels. The results suggest that the metabolic variability is related to the stage of maturation of the gonads, in females, where the hepatopancreas and other tissue studies can store and transfer reserves to support maturation to complement the food intake. Variations in the gonadosomatic and hepatosomatic indices suggest that reproduction occurs principally in summer. As in other decapods, abiotic factors such as water temperature, oxygen content, etc. influence the intermediate metabolism.     

Sterol composition of gonad,muscle and digestive gland of Pecten maximus from Málaga (South Spain)

Sterol composition and content and their seasonal variations over 18 months were investigated in adductor muscle, digestive gland and gonads of Pecten maximus. Sterols were isolated by Silicagel 60 thin layer chromatography and identified by gas chromatography/mass spectrometry. Eleven sterols were identified, with cholesterol, brassicasterol, 24-methylenecholesterol and 22-trans-dehydrocholesterol being the principal components. The same sterols were found in all three tissues independent of season. The relative amounts of each sterol present in each tissue differed. Total sterol levels in gonad and muscle were higher than in digestive gland. Statistically significant differences (P<0.05) were found between the concentrations of each of the sterols isolated from the gonad or muscle and digestive gland. The seasonal variations in the sterol content of the gonad seem be related to the reproductive cycle, while the sterol content of the digestive gland appears to be linked to diet, mainly diatoms or dinoflagellates. The muscle sterol content showed minor changes throughout the year.     

Energy allocation in relation to spawning and overwintering of a diadromous Puyen (<Emphasis Type="Italic">Galaxias maculatus</Emphasis>) population in the southernmost limit of the species distribution

A population of Galaxias maculatus, a native species in southern South America, living under cold-temperate conditions (0°C water temperature with an ice layer covering the stream during the coldest days) and 7 h of light in winter undergoes high energetic demands in the population studied. We analyzed the energy density of gonads, liver, fat and muscle, through calorimetry for the first time in this species. Energy density of fat and liver were extremely high (34.77–56.52 and 29.54–40.77 kJ/g respectively). While perivisceral fat reserves were likely used for overwintering, liver and muscle reserves were used for reproduction. High energy densities were also found in gonads (27.76 kJ/g in ovaries and 25.84 kJ/g in testes). High investment in gonads of males suggests the presence of sperm competition. The temporal variation of the energy content of gonads, liver, fat and muscle indicates that the allocation of energy occurs by the internal transference of energy between organs and tissues.     

Seasonal variations in biochemical composition and energy content of liver, gonad and muscle of mature and immature cod, Gadus morhua (L.) from Balsfjorden, northern Norway

Seasonal energy changes in mature and immature cod of the same size were studied. For most of the year, the variations in energy content in the tissues of both mature and immature cod are similar. In the period from October to January, the fish accumulate energy. From January until spawning in early April there is a fall in the total energy content. The growth of gonads from January until spawning can explain about one-third of the energy decrease in liver and muscle.     

Seasonal variations in biochemical and physicochemical properties of actomyosin and energy content of the liver, gonads and muscle of mature Argentine hake, Merluccius hubbsi Marini

Seasonal variations in energy content of liver. gonads and muscle, and the condition factor (K) of mature hake, were investigated. High energy content values were found in the liver after spawning and during thegonadal restingperiod. Lowenergycontent valuesin liverand highenergycontent values in gonads were observed during the gonadal growth period. In some periods of the reproductive cycle, low values of energy content of muscle were found.
The condition factor profile was similar to the energy content profile of liver and muscle. Physicochemical and biochemical properties of actomyosin were monitored by reduced viscosity and Mg²⁺-ATPase activity. The profiles of these properties were similar to that of the condition factor.     

Seasonal variations in polyhydroxysteroids and related glycosides from digestive tissues of the starfish Patiria (=Asterina) pectinifera

Seasonal variations in the concentrations of individual polyhydroxysteroids and related low molecular weight glycosides in pyloric caeca and stomach of the starfish Patiria (=Asterina) pectinifera collected at one location near Vladivostok have been studied. HPLC analysis on the fractions containing these substances showed a fairly constant composition of steroids in digestive tissues of P. pectinifera in spite of small seasonal variations in the relative concentrations of individual compounds.     

Seasonal acquisition of mineral nutrients by a chalcid gall on lowbush blueberry

Seasonal accumulation of various mineral nutrients by galls of the chalcidHemadas nubilipennis on lowbush blueberry were examined in various phases of gall development. Levels of copper, nickel iron and zinc were higher in tissues of galls in initiation phase compared to tips of ungalled shoots and in general were higher than galls in growth and maturation phases. Levels of manganese and magnesium in gall tissues decrease throughout the season compared to ungalled shoots. Levels of calcium are less in gall tissue in initiation phase compared to ungalled shoots, and elevated in maturation phase. Patterns of mineral concentration within galls at various phases of development are related to known physiological roles of minerals in plant nutrition; however we conclude that patterns are variable and their significance in gall physiology requires further study.     

Field and Laboratory Studies on Some Photosynthetic Bacteria in Aswan High Dam Lake I. Some Physical and Chemical Characteristics

Seasonal variations in some physical and chemical characteristics of samples collected from summer 1984 to spring 1985 and vertically from the surface to the bottom at two sites along the main body of Aswan High Dam Lake and in two side Khors were studied. Water temperature showed seasonal as well as vertical variations. The pH values were in the vicinity of 8.0. Dissolved oxygen concentrations were higher at the surface than at the bottom. The total dissolved solids showed seasonal as well as irregular vertical variations. Bicarbonates, nitrates, and silicates showed a marked increase with depth, while sodium, potassium, calcium and magnesium showed generally a slight or, sometimes, marked increase with depth. Phosphates and sulfates showed a slight or marked decrease with depth. Chlorophyll a decreased with depth while bacteriochlorophyll a increased.     

The autecology of the chub, Squalius cephalus (L.), of the River Lugg and the Afon Llynfi

(1) The pattern of absolute atid relative gonad growth during the life-span and the seasonal gotiad cycle were determined from monthly samples of chub taken from two tributaries of the Herefordshire Wye. (2) A marked change in the pattern of absolute gonad growth was thought to indicate the attainment of sexual maturity. This was found to occur synchronously with corresponding changes in the pattern of body growth described previously and was in agreement with the age at which a seasonal gonad cycle was detectable. (3) Sexual maturity was attained during the eighth year of life (7+) in female chub and in males from the Afon Llynfi, but most males from the River Lugg matured a year earlier. (4) The chub gonads continued to increase in relative size after the attainment of sexual maturity. This was more evident in female chub. (5) Seasonal changes in the gonad condition and weight were followed. Gonad maturation occurred during spring and the gonad mass increased rapidly just prior to spawning. (6) Spawning occurred during June.     

Investigations into the soil mycoecology of Chambal ravines of India

Summary The present investigation deals with the seasonal succession of fungal communities in wheat fields. The studies were performed during the year 1975–76 and involved four study seasons,viz. winter (1975), summer (1975), rainy (1975) and winter (1976). The observations during two winter seasons were done to find out whether or not fungal communities exhibit definite cyclic pattern. Of the 69 isolated species, 25 showed wider ecological amplitude whereas some species were specific of a particular season. Each season was marked by different fungal mycoflora. The population ofAspergillus terreus, a dominant member of the community, along with many other autochthonous species, exhibited a definite periodicity during various seasons. Seasonal variations in the fungal communities, variations in the extent of similarity among the fungal communities during various seasons and the impact of climatic conditions on the components of fungal communities are discussed.     

Seasonal changes of zinc, copper, and iron in gilthead sea bream (Sparus aurata) fed fortified diets

Four groups of gilthead sea bream (Sparus aurata) were fed diets with additional metal contents: a basal diet (diet A) contained Zn at 60.9 ± 1.9 mg/kg diet, Cu at 3.9 ± 0.9 mg/kg diet, and Fe at 138.3 ± 6.8 mg/kg diet; the other diets were supplemented with copper (20 mg/kg, diet B), iron (100 mg/kg, diet C), or zinc (300 mg/kg, diet D). Two consecutive year-classes (0⁺ and 1⁺ age fish) from the same parent stock were examined. Several fish tissues were analyzed for metal contents in five different periods of each year in order to determine (1) the sensitivity of certain tissues as indicators of trace element metabolism and (2) possible seasonal variations. Growth data were similar for gilthead sea bream fed the basal diet and the metal-fortified diets. Mineral concentrations in tissues were found to be little affected by the dietary supplementation of trace elements, suggesting an efficient homeostatic control of these three metal concentrations. Tissues involved in metal metabolism (e.g., liver, kidney, gills) presented greater variations between minimum and maximum values with respect to other tissues (e.g., brain, muscle, eye). Seasonal variations were observed during the 2 yr of this study and were especially evident for zinc and copper concentrations in the liver. The overall pattern of metal variations showed a decreasing trend during the 2 yr. Results from this study indicate that (1) trace element concentrations in fish tissues vary with age and life cycle and (2) trace element requirements may vary in function of age and life cycle.     

Seasonal variation and sex differences in the nutritional status in two local populations of wild Japanese macaques

Seasonal variations and sex differences in the nutritional status in two local populations of wild Japanese macaques (Macaca fuscata fuscata) were examined. It was hypothesized that the ecological condition and/or reproductive strategies of each sex determine the nutritional condition and its seasonal fluctuation in each sex. Morphometric measures such as body mass, thoracic and femoris circumferences, skinfold thickness in four places (triceps, biceps femoris, subscapular, and abdomen), and wet mass of mesenteric and omental fat were used for comparisons between sexes, seasons, and populations. Animals of the Shimane population were larger than those of the Boso population in most morphometric measures, abdominal skinfold, and mesenteric and omental fat mass, suggesting environmental and/or genetic differences in the two populations. Females of both populations had larger skinfolds and mesenteric and omental fat mass than males, indicating that females had more fat than males. Females showed seasonality in most measures, having two peaks of body mass, thoracic and femoris circumferences, abdominal skinfold, and mesenteric and omental fat masses in early spring and late fall. In contrast, males exhibited no clear seasonal variations for most measurements, except for biceps femoris and subscapular skinfolds, which showed peaks in summer. Most morphometric measurements significantly correlated to each other, particularly in females, but most skinfolds had no correlation with other measurements. These findings suggest that sexual dimorphism in body composition and its fluctuation may be affected by the different reproductive strategies of males and females.     

Seasonal changes in tissue weight and biochemical composition for the bivalve Donax trunculus L. on the Algerian coast

Seasonal changes in the body weight and composition of the bivalve Donax trunculus L. from Azur Plage near Algiers, Algeria, were studied during the period September 1971-June 1974. Percentage dry tissue weight was minimal in October–December and rose to reach a peak in spring or summer, the rise corresponding with rapid maturation of the gonads. Decrease in tissue weight in the autumn also coincided with a rapid decline maturity of the gonads between August and October. Lipid content increased with sexual maturity, while carbohydrate content was greatest in the autumn and declined to a seasonal minimum in April–May. The changes are compared with those for D. trunculus in other Mediterranean populations, and for D. vittatus (da Costa) elsewhere in Europe.     

Population biology of Proteocephalus macrocephalus (Creplin) in the European eel, Anguilla anguilla (Linnaeus), in two small rivers

Seasonal changes in populations of Proteocephalus macrocephalus (Creplin) were investigated for 17 months in the European eel, Anguilla anguilla (Linnaeus), in two rivers in Devon, SW England, but no clear seasonal patterns in prevalence and abundance were apparent. Population levels of the cestode are low in both localities, and it is suggested that natural population levels of P. macrocephalus may generally be low. However, growth and maturation of the cestode show marked seasonality with both occurring mainly in early summer.     

Seasonal changes in the chemical composition of fish body and nutritional value of the muscle of the pollan (Coregonus pollan Thompson) from Lough Neagh,Northern Ireland

Studies on the chemical composition of adult pollan were carried out monthly from January to December 1977. Sex, weight of scaled fillet, and gonads were examined in 184 fish. Chemical composition which includes water, fat and ash content was analysed in the whole fish, muscle and gonads. This paper attempts to account for the fat and protein flow within fish of both sexes during gonad maturation. Extreme differences between males and females have been recorded in the fat deposition process during summer and spawning period. In spite of our fragmentary knowledge of spawning behaviour in pollan, an explanation is offered for these phenomena. The changes in fat content of female gonads were followed closely throughout the year and the cost of egg production was estimated as a percentage of the amount of fat deposited in the body. Since a similar growth pattern was found for both sexes of pollan, differences in feeding intensity might account for the difference in energy expenditure. Amino acid content was analysed in muscle and gonads and an Essential Amino Acid Index (EAAI) was calculated. There were some changes in EAAI which depended on sex and season. Finally, a new method for evaluation of muscle production expressed as fat and protein is used to determine the most suitable time for fish harvesting.     

Assessment of body condition in live birds; measurements of protein and fat reserves in the mute swan, Cygnus olor

Condition in animals is often measured in relation to various demands, such as reproduction, migration and cold weather. Usually, indices of protein and fat reserves have to be measured on dead animals. Measurements on live animals enable variations in the condition of individuals to be monitored over time, and can be related to their life histories.
In birds, the size of the breast muscle is the most commonly used measure of protein reserves. A technique for measuring breast muscle thickness was developed, using ultrasound, and was tested on mute swans. The measurements were accurate and highly repeatable. Breast muscle thickness was positively related to the lean dry weight of the breast muscle, and is likely to be a good indicator of total protein reserves.
A system of fat scoring by colour was developed to assess the size of the subcutaneous fat layer. Although the method relies on subjective judgements, the results were highly correlated with the percentage of fat in the subcutaneous layer, and with other measures of fat reserves.
Measurements were made on live, non-breeding swans to monitor seasonal variations in reserves. The seasonal pattern of fat reserves was similar to the normal cycle of weight changes; high in winter and low in summer. There was no change in relation to the moult. No distinct seasonal variation in muscle thickness was found.
There is an unusual pattern of change in the relative size of reserves during emaciation in swans. Muscle reserves appear to be depleted to a greater extent than fat reserves. This is possibly due to the effects of lead poisoning, causing protein necrosis and preventing muscle regeneration.