Protein, lipid, water and caloric contents of immature rainbow trout, Salmo gairdneri Richardson, growing at different rates

Protein, lipid, water and caloric contents of immature rainbow trout, relative to size of whole fish, growing at different rates were examined by use of allometric analysis (y = ax^b, Huxley, 1932). Fish grew at different rates as a result of differences in ration size (satiation, or 4–5% of dry body weight), temperature (7 and 12°C) and bGH (bovine growth hormone) administration. In fingerlings, protein, lipid and caloric contents tended to increase (v. body weight) as a percentage of body composition, whereas above fingerling size, protein decreased while lipid and caloric contents still increased. These trends occurred regardless of growth rate differences. The correlations between protein, lipid, caloric contents and body weight were high so reliable estimates of body components can be made from body weight for all experimental treatments. At satiation rations (7 and 12°C), there were no significant differences in protein content, but lipid and caloric contents were significantly higher in control fish. At low rations, protein and caloric contents were lower than those at satiation rations and lipid was lower than in the control group. On a dry weight basis, in uninjected fish at 12°C, ration size did not influence the percentage composition (protein and lipid) but the low ration group had lower energy values per unit of body dry weight. At low temperature (7°C satiation), fish had lower lipid and higher protein content (dry weight basis) than their controls (12°C satiation), thereby resembling bGH injected fish at satiation rations. Values of caloric content estimated from protein and lipid values by use of standard conversion factors differed sufficiently from caloric values directly determined by bomb calorimetry to suggest that caloric values of lipids may change during growth. The increase in body caloric content during growth apparently results mainly from an increase in the percentage of lipid. The similarity of body composition between different growth rate groups implied a tendency for conservation of relative proportions of components such that body composition can be approximated from body weight. Equations were also given to describe the relationship between water content and body constituents, and the relationship between condition factor (K) and both the body dry weight and lipid content.     

Three weeks of caloric restriction alters protein metabolism in normal-weight, young men

The effects of prolonged caloric restriction (CR) on protein kinetics in lean subjects has not been investigated previously. The purpose of this study was to test the hypotheses that 21 days of CR in lean subjects would 1) result in significant losses of lean mass despite a suppression in leucine turnover and oxidation and 2) negatively impact exercise performance. Nine young, normal-weight men [23 +/- 5 y, 78.6 +/- 5.7 kg, peak oxygen consumption (Vo2 peak) 45.2 +/- 7.3 ml.kg(-1).min(-1), mean +/- SD] were underfed by 40% of the calories required to maintain body weight for 21 days and lost 3.8 +/- 0.3 kg body wt and 2.0 +/- 0.4 kg lean mass. Protein intake was kept at 1.2 g.kg(-1).day(-1). Leucine kinetics were measured using alpha-ketoisocaproic acid reciprocal pool model in the postabsorptive state during rest and 50 min of exercise (EX) at 50% of Vo2 peak). Body composition, basal metabolic rate (BMR), and exercise performance were measured throughout the intervention. At rest, leucine flux (approximately 131 micromol.kg(-1).h(-1)) and oxidation (R(ox); approximately 19 micromol.kg(-1).h(-1)) did not differ pre- and post-CR. During EX, leucine flux (129 +/- 6 vs. 121 +/- 6) and R(ox) (54 +/- 6 vs. 46 +/- 8) were lower after CR than they were pre-CR. Nitrogen balance was negative throughout the intervention ( approximately 3.0 g N/day), and BMR declined from 1,898 +/- 262 to 1,670 +/- 203 kcal/day. Aerobic performance (Vo2 peak, endurance cycling) was not impacted by CR, but arm flexion endurance decreased by 20%. In conclusion, 3 wk of caloric restriction reduced leucine flux and R(ox) during exercise in normal-weight young men. However, despite negative nitrogen balance and loss of lean mass, whole body exercise performance was well maintained in response to CR.     

Protein, lipid and caloric contents of bluntnose minnow, Pimephales notatus Rafinesque, during growth at different temperatures

Changes in the relative proportions of protein, lipid, water and caloric contents of bluntnose minnow growing at various temperatures (15, 25, 30° C) were investigated by application of the allometry equation, y=ax^b . Fish grew significantly faster at 25° C (closest to optimum), more slowly at 30° C and most slowly at 15° C. Protein, as a percentage of body wet weight, tended to increase with fish size at all temperatures ( b > 1.000), whereas in juveniles (<0.7 g) it decreased ( b < 1.000). However, with the exception of the 15° C group, protein as a percentage of body dry weight, decreased in all groups ( b < 1.000). Temperature appeared to modify the body composition of bluntnose minnows, e.g. decreasing temperature led to significantly enhanced protein content during growth. Lipid (%) and caloric content (cal g⁻¹) increased with increasing fish weight ( b > 1). The slower growing fish (15°, 30° C) deposited significantly more lipid (and had higher caloric contents) than those growing most rapidly (at 25° C). Water content (%) decreased with increasing body weight in all groups. Despite intergroup growth rate differences, all groups showed evidence of a tendency to follow similar trends in b values for body constituents and caloric content (except for protein v. body dry weight for the 15° C group). This suggests a general conservativeness of body composition in bluntnose minnow. The correlations between body constituents, caloric content and body weight were high ( r ²>0.9) so that estimates of body composition can be obtained from body weight for all temperature groups.     

Exercise and diet enhance fat oxidation and reduce insulin resistance in older obese adults.

Older, obese, and sedentary individuals are at high risk of developing diabetes and cardiovascular disease. Exercise training improves metabolic anomalies associated with such diseases, but the effects of caloric restriction in addition to exercise in such a high-risk group are not known. Changes in body composition and metabolism during a lifestyle intervention were investigated in 23 older, obese men and women (aged 66 +/- 1 yr, body mass index 33.2 +/- 1.4 kg/m(2)) with impaired glucose tolerance. All volunteers undertook 12 wk of aerobic exercise training [5 days/wk for 60 min at 75% maximal oxygen consumption (Vo(2max))] with either normal caloric intake (eucaloric group, 1,901 +/- 277 kcal/day, n = 12) or a reduced-calorie diet (hypocaloric group, 1,307 +/- 70 kcal/day, n = 11), as dictated by nutritional counseling. Body composition (decreased fat mass; maintained fat-free mass), aerobic fitness (Vo(2max)), leptinemia, insulin sensitivity, and intramyocellular lipid accumulation (IMCL) in skeletal muscle improved in both groups (P < 0.05). Improvements in body composition, leptin, and basal fat oxidation were greater in the hypocaloric group. Following the intervention, there was a correlation between the increase in basal fat oxidation and the decrease in IMCL (r = -0.53, P = 0.04). In addition, basal fat oxidation was associated with circulating leptin after (r = 0.65, P = 0.0007) but not before the intervention (r = 0.05, P = 0.84). In conclusion, these data show that exercise training improves resting substrate oxidation and creates a metabolic milieu that appears to promote lipid utilization in skeletal muscle, thus facilitating a reversal of insulin resistance. We also demonstrate that leptin sensitivity is improved but that such a trend may rely on reducing caloric intake in addition to exercise training.     

Effects of starvation on oxygen consumption, ammonia excretion and biochemical composition of the hepatopancreas on adult males of the False Southern King crab Paralomis granulosa (Crustacea, Decapoda)

Adults of the False Southern King crab, Paralomis granulosa, were starved between 0 and 12 days to evaluate the impact of fasting on the oxygen consumption, nitrogen excretion, O/N ratio and changes on biochemical composition of the hepatopancreas. During the experiment, no mortalities were recorded; physiological changes were detected after 6 days of fasting with an increase of nitrogen excretion (p<0.05). After 9 days of starvation, the crabs showed a maximum decrease in the lipid content (4.3+/-1.2%, p<0.05), accompanied by an increase in oxygen consumption (53.1+/-10.9 microg O2 h(-1) g(-1)). The lowest O/N ratio was detected after 6 days (6.4+/-4.8) and the highest after 12 days of fasting (38.1+/-20.4), indicating that initially crabs utilized proteins as source of energy , followed by lipids. Moreover, after 12 days, there was a significant increase in the hepatosomatic index (HI) and total lipid content (9.7+/-1.0%, p<0.05), which could be associated with the re-absorption of other tissues to the hepatopancreas. Our results provide new information on this species that shows a different pattern of adaptation for each period of starvation and a good correlation between physiological and biochemical parameters. The ability to withstand and recover from periods of nutritional stress is an important adaptation for survival of any organism that must sporadically endure periods of limited food supply.     

Gross and histological observations of ovarian development and related condition changes in American plaice

The largest increase in gonadosomatic index of American plaice Hippoglossoides platessoides occurred between January and February. Hepatosomatic index was lowest in the spawning season, suggesting cessation of feeding activity during spawning, but rose immediately in July when condition factor recovered from its low spawning level. Increases in white muscle water content during the spawning season suggests protein depletion. Conservation of some white muscle fibres is suspected, but no regular pattern in area conserved was found. Gonad development was advanced in December and in April some gonads were showing evidence of spawning. Ovaries from spawning females showed hydration patterns and histological detail consistent with batch or serial spawning strategy. Evidence of recent spawning activity, including the presence of postovulatory follicles, was found in ovaries that also contained oocytes undergoing exogenous vitellogenesis. Oocyte size frequency distributions show a gap in size between cortical alveoli and vitellogenic oocytes prior to spawning which does not exist during the spawning season. This may represent the ability of plaice to push oocytes through vitellogenesis from a previtellogenic condition during the spawning period. The increased white muscle moisture during June and July may reflect the use of muscle protein to bring oocytes through vitellogenesis for the current spawning season.     

Carbon, nitrogen and caloric content of eggs, larvae, and juveniles of the walleye pollock, Theragra chalcogramma

Measurements of dry weight (wt), carbon (C), nitrogen (N) and calories were made on walleye pollock eggs (0.24 mg, 35.3% C, 8.3% N, and 4.6 kcal g⁻¹ dry wt), larvae (0.16 g, 42.9% C, 11.1% N and 5.1 kcal g⁻¹ dry wt) and juveniles (22.4 g, 47.2% C, 9.0% N and 5.6 kcal g⁻¹ dry wt). For juvenile fish (9–360 g wet wt) the measured values were related to dry weight and Fulton's condition factor index (CFI) by regression models. The CFI was a better predictor of body composition than dry weight. As CFI improved from a minimum starvation level of 0.42 to a maximum of 1.16, body caloric content, percentage C, and the C/N ratio increased (kcal g⁻¹ dry wt = 4.4 CFI + 1.7, percentage carbon = 49.7 CFI^0.5, C/N ratio = 5.0 CFI + 0.9), while percentage N and percentage ash decreased (percentage N =−3.5 CFI + 12.1; percentage ash = 9.1 CFI^−1.4). The results of this study suggest that seasonal C, N and caloric content of young pollock can be estimated from measurements of Fulton's condition factor index.     

Biochemical composition,condition index,and energy value of Ostrea peulchana (D'Orbigny): relationships with the reproductive cycle

Seasonal changes in body weight, biochemical composition, energy value, and condition index of Ostrea puelchana (D'Orbigny, 1846) from Laguna Punta Cero (Chubut, Argentina), were studied between February 1983 and April 1984. These values were determined for the soft tissues of the whole animal and, separately, from the adductor muscle, digestive gland-gonad complex, and a fraction containing all remaining organs. The main muscle components were proteins whereas glycogen and lipids were stored in the digestive gland-gonad complex. Weight and energy reserves decreased in winter during the beginning of the reproductive cycle and starvation period. In spring, there was a rapid growth of the gonad coincident with an increase in glycogen, lipid, and protein contents. In summer the glycogen content decreased with spawning, and proteins showed the highest values. The glycogen index appears to be suitable as an indicator of the physiological state. During the post-spawning period, in the autumn, the animals attained their best condition in quantity of flesh with a shigh energy value.     

Variation of diet and food consumption of the scaldfish Arnoglossus laterna(Walbaum, 1792)

Although Arnoglossus laterna (Walbaum, 1792) is a common benthic fish in Portugal, several aspects of its feeding ecology remain incomplete. In this study, diet was examined and the food consumption estimated on inshore waters in the central coast of Portugal. The diet of the scaldfish included mainly mysids, amphipods and polychaetes, while the decapod Philocheras bispinosus Hailstone was the most frequent prey. Variation in the diet according to fish size (two size‐classes), sex and spawning/non‐spawning seasons was examined. Significant differences in diet composition were found between seasons, whereby the most frequently consumed prey in the non‐spawning season were crustaceans, while polychaetes and nemerteneans comprised most of its diet in the spawning season. The average value of the vacuity index was very similar between seasons (24.7% non‐spawning season and 25.0% spawning season). Diet overlap between size‐classes and sexes was high, but low between the two seasons. Food consumption of A. laterna was estimated based on diet characterization and evacuation rate. The estimate of the daily food consumption was 1.15 mg dry weight for the non‐spawning season and 1.67 mg dry weight for the spawning season. Significant differences in consumption rates were found between size‐classes and sexes. Larger individuals showed a higher consumption rate than smaller individuals. Females consumed more food than males in the non‐spawning season, while in the spawning season males consumed more than females.     

Spawning and season affect lipid content and fatty acid composition of ovary and liver in Japanese catfish (Silurus asotus)

The influences of spawning and season on lipid content, lipid classes, and fatty acid composition were assessed in ovary and liver of wild and cultured Japanese catfish (Silurus asotus). The lipid content (7.3+/-1.6 g/100 g wet wt.) of ovary from wild catfish at spawning was higher than that at post-spawn. However, no influence of spawning on the lipid content of liver was observed. Docosahexaenoic acid [DHA, C22:6(n-3)] in ovary lipids was 12.3+/-0.5% of total fatty acids. The percentage of n-7 monounsaturated fatty acids in triacylglycerol from the ovary and liver in the spawning season was high. Percentages of C22:6(n-3) in phosphatidylcholine and phosphatidylethanolamine from ovary were higher during spawning than after spawning. No significant differences were observed in the lipid content of ovary and liver from cultured catfish between seasons (summer vs. winter). Content of arachidonic acid (C20:4n-6) in ovary and liver from cultured catfish was higher in summer than in winter. There were differences in lipid classes of ovary and liver by spawning and season. These results suggest that the lipid metabolism in Japanese catfish is greatly influenced by spawning and season.     

Various methods to determine the gonadal development and spawning season of the purplish Washington clam, Saxidomus purpuratus (Sowerby)

The monthly variation in reproductive cycle, condition factor (fatness), gonad index (GI), ovarian egg diameter and biochemical composition [RNA, DNA content and their ratio RNA/DNA (R/D)] were compared to determine the spawning season of the purplish Washington clam, Saxidomus purpuratus, collected from the west sea of Taean, Korea. All these factors were correlated to the spawning season from May to October. Monthly variation and concentration of the R/D ratio especially represented indicative information about the processes of gonad development and spawning patterns. The increases in R/D ratio in the ovaries corresponded with increases in ovarian egg diameters and the GI during the spawning season. The peak of R/D and RNA content in females was a good indicator of sexual maturation and the DNA content in males. During winter between November and January, the value of fatness, GI, egg size, RNA and DNA content were lower than in other seasons, indicating depletion of energy reserves and lower metabolic demands because of colder temperatures.     

Proximate composition, fatty acids, cholesterol, minerals in frozen red porgy

The proximate composition of frozen red porgy (Pagrus pagrus) was determined. The moisture, ash, protein and total lipids (45.5+/-1.4% PL of which 90.4+/-2.0% PhL) were found to be 71.7+/-1.0%, 1.73+/-0.12%, 21.5+/-0.8% and 0.81+/-0.09% of the wet muscle tissue, respectively. 16:0 and 18:0 were the main SFA, 18:1 (omega-9 and omega-7) the main MUFA while DHA, EPA and arachidonic acid were the main polyunsaturated fatty acids (PUFA). The SFA/PUFA ratio was 1.5 and the omega-3/omega-6 ratio was 3.02. The cholesterol content was found to be 8.18+/-0.34 mg/100 g of the wet muscle tissue. Ni, Cr, Mn, Cu, Zn, Fe and Mg were determined in the muscles, skin, hepatopancreas and head of the fish. The covering percentage of the recommended daily allowance/intake (RDA/RDI) for each mineral, in the muscle tissue, has been calculated to 14.2% (males) and 7.89% (females) for Fe, 2.87% for Cu, 4.07% for Zn 0.4% for Mn, 13.9% for Ni, 20.2% for Cr and 10.4% for Mg.     

Temporal variation in condition index and meat quality of Lunella undulata (Turbinidae), in relation to the reproductive cycle

ABSTRACT

Lunella undulata is a subtropical-temperate marine gastropod which is harvested commercially from temperate reefs in Australia. This paper aimed to evaluate monthly variation in the condition index (CI) and biochemical composition of the foot tissue of L. undulata in relation to the spawning cycle. The gonadosomatic index (GSI) varied significantly between males and females and across months (P?=?0.0001), ranging from 43% to 70% in males and 41% to 71% for females. The highest GSI, as well as the highest CI for both sexes was recorded in December and April, whilst meat yield peaked in January, September and October. Protein, lipid, fatty acid and heavy metals in the foot tissue also significantly varied between months (P?<?0.05). Throughout all 14 months of sampling, the foot tissue of L. undulata showed good nutritional quality, with high levels of protein and the polyunsaturated fatty acids, docosapentaenoic acid, eicosapentaenoic acid and arachidonic acid. Overall, despite some temporal variability in the biochemical composition, L. undulata could be harvested at any time of the year for human consumption, although it may be best to avoid peak spawning times, which occur around January in northern NSW.     

Seasonal variations in biochemical constituents of the clam,Paphia laterisulca

1. The total protein, fat and glycogen contents were estimated from the edible clam, P. laterisulca. Seasonal variations in these constituents along with the water content were studied.
2. The gonad index in P. laterisulca was found to increase during the ripe condition and in winter (December–January) and decrease on spawning.
3. A relatively high water content was obtained during monsoon (June to September). This might be due to the loss of salts and gain of water in low salinities.
4. Protein content varied with the reproductive cycle of the clam. The level reached its peak in the mature stage and declined on spawning. Immature clams showed less protein content than gravid ones.
5. Lipid content started to increase as the gametogenesis commenced, reached its peak in fully mature condition (August) and sharply declined due to the shedding of gametes during spawning.
6. Glycogen content was high during the period of active gameto-genesis (May–June). A sharp decrease took place when the clams were fully ripe (July). The glycogen might have been utilized in the formation of active ripe gametes.
7. After starvation for twelve days, total protein and fat contents remained constant, while glycogen content decreased by 66.82%. The water content increased by 4.67%.
8. Seasonal variation in the organic constituents are discussed in relation to the reproductive cycle of the clam.

     

五种丛生状棕榈植物叶热值的月变化研究

对5种丛生状棕榈植物一欧洲棕、细叶棕竹、小箬棕、玲珑椰子、缨络椰子的叶片热值和灰分含量的月变化进行了研究,结果表明,5种植物具有较高的灰分含量,但灰分含量的月变化趋势各不相同;欧洲棕、细叶棕竹、小箬棕3种植物干重热值的月变化趋势有些差异,同属的缨络椰子、玲珑椰子干重热值的月变化趋势基本相似;缨络椰子、小箬棕的干重热值与灰分含量具有显著的线性相关(P<0．05),而其余3种植物的干重热值与灰分含量相关性不显著(P>0．05);从去灰分热值的月变化来看,细叶棕竹与小箬棕,缨络椰子与玲珑椰子的月变化趋势相似。     

Fatty acid composition,cholesterol and fat‐soluble vitamins of wild‐caught freshwater spiny eel,Mastacembelus simack (Walbaum, 1792)

Because of its local commercial value, the proximate nutritional composition, fatty acid composition, cholesterol and fat‐soluble vitamins of spiny eel (Mastacembelus simack Walbaum, 1792) were determined in 20 specimens caught in Keban Dam Lake, Elaz??, Turkey in September 2009. Moisture, protein, lipid, ash and cholesterol contents of the spiny eel were 75.9, 17.1, 10.9, 1.0% and 52.6 mg per 100 g, respectively. Fatty acid composition showed that total polyunsaturated fatty acids (PUFA) were the highest (37.1%), followed by monounsaturated fatty acids (MUFA, 35.5%) and saturated fatty acids (SFA, 27.4%). The relation between PUFA and SFA (1.35) was comparable to that of some fish species, and PUFA : MUFA : SFA ratio (1.35 : 1.29 : 1) was very close to that recommended by nutritionists. Among the vitamins (A, D, E and K) analyzed, the vitamin E content was highest followed by D, K and A. In conclusion, M. simack is rich in proteins, unsaturated fatty acids and vitamins and low in cholesterol, with a reasonable PUFA : SFA and PUFA : MUFA : SFA ratio as recommended by nutritionists. M. simack can therefore be recommended for human consumption as a good source of nutrition.     

Sexual dimorphism in the energetics of reproduction and growth of North Sea plaice, Pleuronectes platessa L.

The chemical composition and energy content of North Sea plaice during the spawning period were examined in mature males and females and in immature fish, to study differences in the allocation of energy over reproduction and somatic growth between the sexes. At the beginning of the spawning period mature males and females had equal dry weights of lipid that were 70% higher than in immatures. Protein content in mature males was equal to that in immatures but was 23 % higher in mature females. Immature males and females did not differ in chemical composition. At the end of the spawning period, spent and immature fish had equal lipid contents, but protein content in spent females was 10% lower than in spent males, and 17% lower than in immatures. Gross energy content of the body decreased by 44% (65·2 to 36·3 J cm^-3) in mature females, 27% (55·0 to 40·OJ cm^-3) in mature males, and 9% (48·7 to 44·2J cm^-3) in immatures. Energy content of plaice eggs was estimated at 6·60 kJ per 1000 eggs. Reproductive investment was estimated from the energy loss during the spawning period and included the energy of sex products and spawning metabolism. Somatic growth comprised the annual increase in energy content of fish. The pattern of energy allocation over reproduction and somatic growth differed between males and females. Males started their reproduction at a smaller length and a younger age and allocated a higher proportion of the available energy into reproduction than females. Available energy resources for somatic growth and reproduction (surplus production) were equal between the sexes up to a length of about 30 cm. Beyond this length male surplus production levelled off whereas female surplus production continued to increase. The differences in surplus production and the allocation patterns are discussed. For female plaice the energy allocated into egg production was estimated as between 48 and 64% of the total amount of energy lost during spawning. The remaining energy is used for metabolism during the spawning period, yielding an estimate of the metabolic rate of mature females of between 6·4 and 9·1 kJ day^-1. A maximum estimate of the metabolic rate of mature males was 7·4 kJ day^-1.     

Energy reserve utilization in northern elephant seal (<Emphasis Type="Italic">Mirounga angustirostris</Emphasis>) pups during the postweaning fast: size does matter

During fasting most mammals preferentially utilize lipid reserves for energy while sparing protein reserves. This presents a potential problem for marine mammals that also depend on lipids as a major component of blubber, the primary thermoregulatory structure. Because of this dual function for lipid, rates of lipid and protein utilization should be closely regulated during the postweaning fast in northern elephant seals (Mirounga angustirostris). To quantify energy expenditure during the fast, we measured body mass and composition of 60 pups at 2.3+/-0.2 days and 55.9+/-0.3 days postweaning in 1999 and in 2000. Body condition differed significantly between years. At weaning, body mass (125.9+/-3.8 kg) and percentage lipid content (39.3+/-0.6% of body mass) in 2000 were significantly greater than body mass (115.2+/-3.1 kg) and percentage lipid content (35.8+/-0.6%) in 1999. In general, percentage lipid content increased with body mass, and fatter pups utilized lipid at relatively higher rates during the fast. Lipid fueled 85-95% and 88-98% of energy expended by pups in 1999 and 2000, respectively. Postweaning fast duration (32-78 days) was positively correlated with body mass and hence lipid content at weaning. This suggests that body composition at weaning influences lipid utilization patterns and ultimately the duration of the postweaning fast in northern elephant seal pups.     

Seasonal cycles in total chemical composition of two Lake Baikal benthic-pelagic sculpins (Cottocomephorus, Cottoidei)

Annual cycles in chemical composition of the body, liver, gonads, red and white muscles were determined for two medium fat sculpins, Cottocomephorus grewingki and C. inermis , endemic to Lake Baikal. Their total lipid content ranged from 3 to 9% during the year. The content of defatted dry substance was 14–17%, similar to the protein content of the other Baikalian cottoid fishes. The prespawning period was characterized by a positive lipid and protein balance in both species. In C. grewingki the liver performed largely a metabolic function, whereas in C. inermis it served also as a storage site for lipid reserves. During spawning, total body lipids of females of both species showed a two- to threefold decrease. Males of C. grewingki guarding nests deplete greatly their total body lipids, which decrease seven- to ninefold by the time of larval hatching in comparison with the prespawning period, and constitute 1–2%. After spawning, lipid reserves of C. grewingki were quickly restored to the initial level (from about 3 to 9%) and maintained during the long sexual maturation period. In C. inermis total body lipids increased only twofold in comparison to those observed during the spawning period.     

Trockengewicht und Kaloriengehalt sich entwickelnder Heringseier

Dry weight and caloric content of eggs from spring spawning western Baltic Sea herrings have been determined employing the bomb calorimetry technique. Water temperature throughout incubation was kept at 8.0°±0.2° C. Average dry weight and caloric content values of one pist fertilized egg are 0.170 mg (0.124 mg without chorion) and 0.748 cal (without chorion), respectively. The caloric content per egg decreases progressively during the incubation period (Fig. 2). The same holds for the dry substance of the egg (Fig. 1). Energy extraction efficiency related to dry weight is 67.8%, the efficiency related to dry organic substance 70.4%, and the caloric efficiency 63.7%.