Sea Bream Eggs Research Articles

Effect of temperature on embryonic development in sharpsnout seabream (Diplodus puntazzo) eggs

Embryonic development of sharpsnout seabream (Diplodus puntazzo) was studied at eleven water temperatures (two degree intervals from 12 to 32°C). Embryos successfully developed at temperatures of 16-28°C. Cells did not divide at the temperature extremes of 12 and 32°C. Total mortality was observed by the 128 cleavage stage at 14°C and all eggs were dead by the time the embryos extended 2/3 of the internal circumference of the egg at 30°C. There was an inverse relationship between incubation temperature and the rate of embryonic development.

Changes in lipid class and fatty acid composition during development in white seabream ( Diplodus sargus) eggs and larvae

To establish the changes which occur during embryogenesis and early larvae development, eggs, yolk-sac larvae (one day old larvae) and absorbed yolk-sac larvae (three day old larvae) of white sea bream were examined for lipid class and fatty acid composition. The development was characterized by a decrease in all lipid classes with the exception of phosphatidylserine (PS) and fatty free acids (FFA) which increased, and sphingomyelin (SM) which remained unchanged. The changes observed in lipid class content and the decrease in fatty acids in total lipid (TL) reflect the utilization and mobilization of lipids during both embryogenesis and early larvae development. Fluctuations in the relative composition of fatty acids in phosphatidylcholine (PC) during development suggest a selective bulk uptake and catabolism of fatty acids in this lipid class. Unlike PC, catabolism of triacylglycerol (TG) fatty acid appears to be non-selective. During development, the decrease in levels of polyunsaturated fatty acids (PUFA) eicosapentaenoic (20:5 n−3, EPA) and docosahexaenoic (22:6 n−3, DHA) in total lipid denotes their utilization as energy substrate by Diplodus sargus larvae.

Oxygen deficiency during somitogenesis causes centrum defects in red sea bream, Pagrus major (Temminck et Schlegel)

Vertebral deformities in red sea bream, Pagrus major, remain serious obstacles to the improvement of seedling quality for its aquaculture. However, the causalities of the deformities remain unclear and prevention methods have not yet been established. In this paper, oxygen deficiency during somitogenesis was demonstrated to cause centrum defects (formerly called fused vertebrae in many cases), which are the major vertebral deformity in cultured red sea bream. An induction experiment of centrum defects was conducted by placing fertilized red sea bream eggs under low dissolved oxygen conditions (10.3–16.6%). The low oxygen treatment was carried out for five different developmental stages of embryo: two-cell stage to blastula stage; gastrula stage; three to 10 somites stage; 11–17 somites stage and 18–24 somites stage. Oxygen deficiency during somitogenesis induced a high incidence of centrum defects. In contrast, it hardly induced centrum defects during the other stages. The dissolved oxygen concentration in the rearing water should be carefully regulated for fertilized eggs, especially during somitogenesis to reduce the incidence of vertebral deformities in the red sea bream.

Biochemical egg quality determination in the gilthead seabream, Sparus aurata: reproducibility of the method and its application for sharpsnout seabream, Puntazzo puntazzo

The reproducibility of a recently developed method for egg quality determination in gilthead seabream ( Sparus aurata) eggs was investigated with different broodstock fish and eggs from different stages of spawning time. The method uses activities of acid phosphatase, adenylate kinase, glucose-6-phosphatase, and transaldolase, and levels of amino acids, monosaccharides, and sialic acids as markers and multiple regression models to predict the egg quality. The method has general validity in the present study indicated by highly significant correlations obtained between calculated and experimentally obtained % prehatch survival. Moreover, highly significant correlations were found between predicted % prehatch survival and % posthatch survival. These methods were applied to Puntazzo puntazzo. The multiple regression models for egg quality determination in S. aurata were not useful in this species. However, multiple regression models adapted for P. puntazzo could predict the egg quality with a statistically high significance.

Investigations on the metabolism of viable and nonviable gilthead sea bream (Sparus aurata) eggs

Abstract The present study investigated selected biochemical parameters in viable and nonviable eggs of the gilthead sea bream, Sparus aurata . During embryogenesis, S. aurata eggs had a balanced and stable energy metabolism as the levels of adenosine nucleotides and acetyl-CoA, and the adenylate energy charge (EC), remained constant. Mg 2+ -dependent ATPase, which is involved in membrane-driven ion transport during oxidative phosphorylation, increased in activity. In nonviable eggs, the levels of ATP, acetyl-CoA, the adenylate energy charge, and the activities of malate dehydrogenase were significantly decreased in comparison to viable eggs. Viable eggs had high Na + /K + -ATPase activity which remained constant during embryogenesis while Ca 2+ -ATPase activity increased. These enzymes were similarly high in nonviable eggs indicating that the ability for ion transport and for osmoregulation did not differ. However, nonviable eggs contained nonphysiological high levels of magnesium and calcium ions indicating ion influx from the seawater. As the phospholipid levels were significantly lower in nonviable eggs, this ion influx is thought to be related to changed composition of the oolemma. Activities of glucose-6-phosphate dehydrogenase, transaldolase, phosphofructokinase, and pyruvate kinase were constant in viable eggs of S. aurata during embryogenesis. Pyruvate carboxylase increased in activity in the embryonic stage. The occurrence of these enzymes indicated the presence of the enzymatic system for glycolysis for gluconeogenesis and for the pentose phosphate pathway. The monosaccharide levels (i.e. total amount, glucose, fructose, galactose) increased steadily during egg development. Monosaccharides are necessary for nucleic acid synthesis levels, which increased during embryogenesis, and may also play a role as osmotically active compounds. In nonviable eggs, levels of all assayed sugars as well as activities of pyruvate carboxylase and transaldolase were very significantly decreased. Enzymes involved in the catabolism of proteins and amino acids (proteases, aspartate aminotransferase, glutamate dehydrogenase) were constant in the viable eggs with the exception of aspartate aminotransferase, which increased significantly in the embryonic stage. Nonviable eggs had lower activities of glutamate dehydrogenase than viable eggs, while the other enzyme activities were similar. Amino acid levels and inorganic phosphate levels were lower in nonviable than in viable eggs.

Lipid and fatty acid composition of ovaries from wild fish and ovaries and eggs from captive fish of white sea bream ( Diplodus sargus)

The fatty acid composition of ovaries from wild white sea bream and ovaries and eggs of captive white sea bream were investigated to estimate the fatty acid requirements of this species. The total lipid (TL) content in wild fish ovaries was similar to that found in ovaries and eggs from captive fish. The general pattern of the fatty acid distribution in lipid of ovaries from wild fish and ovaries and eggs from captive fish was similar. In total lipid, no significative differences in total monoenes, n−6, n−3 and n−3 highly unsaturated fatty acids (HUFA) were found. However, the relative percentage of specific fatty acids differed between wild and captive fish. Thus, arachidonic acid (20:4 n−6, AA) percentage was higher in wild ovaries than in ovaries and eggs from captive fish, whereas eicosapentaenoic acid (20:5 n−3, EPA) showed the opposite trend. In consequence, wild fish presented a lower EPA/AA ratio in their ovaries when compared with ovaries and eggs of captive fish. These differences were extended to all lipid classes studied (triacylglycerol (TG), phosphatidylcholine (PC) and phosphatidylethanolamine (PE)). The present study suggests that essential fatty acids, specially EPA and AA of the diet supplied to the captive white sea bream broodstocks, do not seem to be in an appropriate proportion for this species.

Cyclic ADPR and calcium signaling in sea bream (Sparus aurata) egg fertilization.

The cell egg is in a state of quiescence and only after its fusion with the sperm, a series of pre-programmed metabolic processes will be activated, culminating with embryonic development. The egg/sperm fusion induces a transitory increase of Ca(2+) in the cytoplasm, which is responsible for the activation of both precocious and late reactions. The release of Ca(2+) occurs by stimulation of the ionic specific channels. In addition to IP(3), a new Ca-release inducer was recently evidenced, cyclic ADP ribose (cADPR), in some invertebrates and mammals. Here, we report the first evidence of the cADPR presence in fish. Our data also demonstrate that in the sea bream egg, cADPR is involved in the fertilization process; in fact, its level increases after the entrance of the sperm. By in vitro experiments, it was shown that cADPR induces a release of Ca(2+) in the egg homogenate, indicating that in sea bream, the increase of cADPR can induce an intracellular Ca(2+) release. Since cADPR is a product of NAD(+) metabolism, the activity of several enzymes involved in the NAD(+) metabolism was investigated. Sea bream eggs are pelagic and only floating eggs after insemination develop into viable embryos. In the present work, NAD(+) metabolism was studied in both types of egg. All the tested enzymes showed similar specific activity in both floating and sinking eggs. In the latter, cADPR was not detectable and the nucleotides content was significantly lower, evidencing a scarce energetic charge in sinking eggs.

Disinfection of Sparus aurata eggs with glutaraldehyde

This study was conducted to determine suitable conditions fordisinfecting eggs of gilthead sea bream (Sparus aurata)with glutaraldehyde. Effects of the developmental stage (4–8 cells,morula, blastopore closure or heart beating), of the concentration (C = 200,300or 400 ppm) and of the duration of the glutaraldehyde treatment (T= 2 to 10 min) were investigated. Before the blastopore closurestage, egg manipulation and treatment induced mortality. After this stage, thetoxicity of the glutaraldehyde treatment was negligible if the value of theproduct C × T was less than 1000. Above this value, the percentage ofhatching and of normal larvae decreased and the percentage of imprisoned larvaeincreased. Toxic effects of glutaraldehyde varied according to the egg qualityat the time of the treatment. It was concluded that 200 ppmglutaraldehyde for 4 min, at the blastopore closure stage or attheheart beating stage, were acceptable conditions for disinfecting gilthead seabream eggs at 18 °C.

Structure of a full-length cDNA clone for the pro-α1(V/XI) collagen chain of red seabream

The cDNA of type V/XI collagen α1 (rsCOL) chain has been isolated from cells established from eyed-period eggs of red seabream, Pagrus major, and sequenced. The amino acid sequence deduced from red seabream α1(V/XI) chain resembles that of type XI collagen α1 chain. On the other hand, tissue distribution of rsCOL resembles that of type V collagen based on RT–PCR analysis. This is the first report of the cloning of the full-length cDNA of type V/XI collagen α1 chain from fish.

Eggs of gilthead seabream Sparus aurata L. as a potential enrichment product of Brachionus sp. in the larval rearing of gilthead seabream Sparus aurata L.

The gilthead seabream Sparus aurata L. is a sequential spawner whose reproductive cycle can be manipulated to obtain year-round egg and fry production. Hence, there is an overproduction of eggs in commercial hatcheries that is normally wasted. Two feeding experiments were conducted with the purpose of investigating the potential use of fresh and freeze-dried gilthead seabream eggs for the enrichment of live preys. The first experiment was also designed to study the possibility of using freeze-drying as a conservation process for eggs in excess. Larvae were reared for 20 days after hatching (DAH),on a diet of Brachionus sp. As experimental controls, the commercial enrichment emulsion SUPER HUFA was used in the first experiment, and the microalgae Nannochloropsis sp. in the second. This study demonstrated the potential of gilthead seabream eggs as an enrichment product to be used in the feeding of the first larval stages of Sparus aurata L. The data obtained emphasize the need to have an overall perspective of the nutritional requirements of the organisms in culture.

SHORT COMMUNICATION Effects of salinity and temperature on incubation period, hatching rate and morphogenesis of the red sea bream

The red sea bream, Pagrus major, which is widely distributed throughout the Far East, is the most important species of the family Sparidae for marine aquaculture in Japan (Ochiai and Tanaka, 1986). The total production of market-size red sea bream in Japan was over 72 000 tonnes (t) in 1993, with approximately 28% of the fish being derived from cultivation (Taya, 1995). In 1995 about 30 million red sea bream juveniles were produced: about 22 million being used for restocking into coastal waters, and the remainder were on-grown in commercial farms (Morita, 1997). In southern Japan, the natural spawning season starts at the end of February and lasts until early June, when water temperatures are within the range 15–23 °C (Higuchi, 1977). In captivity, the spawning season of the red sea bream starts in April and comes to an end in June (Harada, 1969; Kitajima, 1978). Although there are several reports, published mostly in Japan, on aspects related to red sea bream culture, relatively little is known about the environmental requirements of the early life stages of this species. Some effects of temperature and salinity on the embryonic development of red sea bream eggs were described by Matsuura and Kakuda (1980) and Yoo et al. (1991), while Apostolopoulos (1976) provided some information about the combined effects of these factors on the hatching of red sea bream eggs. The current study was undertaken to provide information about the effects of salinity and temperature combinations on the length of the incubation period, hatching rate and appearance of newly hatched larvae of the red sea bream. The experiments were carried out at the Fishery Research Laboratory of Kyushu University in 1994. Naturally spawned eggs were collected from a broodstock tank of 3 m3 water capacity during the spawning season (which in Kyushu is early April to June), washed carefully with fresh filtered seawater and transferred directly to the experimental room. Water temperature in the spawning tank during the experimental period ranged from 16.5 to 20.0 °C, and salinity corresponded to the normal salinity of water in the adjacent bay (29.0–32.5‰). Ten trials were conducted to test

Effect of n − 3 HUFA level in broodstock diets on egg quality of gilthead sea bream ( Sparus aurata L.)

A variety of morphological, biological and biochemical parameters of freshly spawned eggs of gilthead seabream ( Sparus aurata L.) were studied to determine the optimum n − 3 HUFA level in broodstock diets necessary to obtain a high-quality spawn. The effect of very high dietary n − 3 HUFA levels on fish reproduction was also investigated. Broodstock were separated into 8 groups and fed four diets containing different levels of n − 3 HUFA, ranging from 1.13 to 3.15%, for 3 months. Spawning and egg qualities were evaluated daily by 7 parameters. Besides, 8 samples of eggs were taken during the experimental period and were analyzed for proximate and fatty acid composition. After 3 weeks of feeding, significantly improved spawning quality in the broodstock fed 1.6% n − 3 HUFA was observed in terms of fecundity, hatching and larval survival. Unfertilized egg rates were significantly reduced by the increase in dietary 20:5n − 3. The highest level of dietary n − 3 HUFA was associated with a decreased fecundity and yolk sac hypertrophy in just hatched out larvae, n − 3 HUFA content in the eggs showed a positive correlation with dietary n − 3 HUFA, mainly due to the change in 20:5n − 3 content of the eggs.

Effects of salinity and temperature on incubation period, hatching rate, and morphogenesis of the silver sea bream, Sparus sarba (Forskål, 1775)

Effects of salinity and temperature on eggs of silver sea bream ( Sparus sarba) were studied in laboratory experiments. Naturally fertilized eggs were incubated under 60 different combinations of constant temperature (13.0, 15.0, 18.5, 22.0 and 23.5°C) and salinity (8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48 and 52‰). Incubation period, hatching period, hatching rate, abnormalities and total length of newly hatched larvae were investigated. The relation between incubation period and temperature was expressed for salinity levels of 24, 28, 32, 36, 40 and 44‰. Hatching occurred between 12 and 52‰ and between 13.0 and 23.5°C. Higher hatching rates of normal larvae were observed at 18.5°C between 20 and 36‰ and at 22.0°C between 28 and 32‰. Largest larval size was observed at 22.0°C and between 28 and 36‰. Using multiple regression analysis the calculated maximum yield of normal larvae was 66.7% at 19.4°C and 31.4‰.

Energy content and chemical composition of gilthead seabream, Sparus aurata L., eggs

Abstract. Gross energy, ash content and elemental composition of carbon, nitrogen and hydrogen in eggs of the gilthead seabream, Sparus aurata L., have been determined throughout several spawning seasons. Also, changes in the biochemical components during embryonic development have been analysed. Gross energy of seabream eggs was approximately 1 J per egg. Dry weight of individual eggs at fertilization varied from 39 to 50μg, the chorion accounting for about 20% of total dry weight. However, there were no differences in carbon, nitrogen, hydrogen and ash percentages. From fertilization to hatching eggs lost 7·2% of total energy (chorion not included). The possible relationship between egg energy content and recent emerged larvae is discussed.

Nutritional studies in the seed production of fish-XXI. Effect of polar and nonpolar lipids from krill on quality of eggs of red seabream Pagrus major.

Red seabream broodstock were fed on various diets shortly before spawning to reexamine the effectiveness of phospholipid and astaxanthins for the improvement of egg quality in comparison to frozen raw krill or vitamin E. The rate of buoyant eggs was lowest in the broodstock fed the control diet, and the value was elevated by supplementation of 200mg α-tocopherol, 2.5% krill polar lipids and 2.5% krill non-polar lipids or by feeding frozen raw krill. The rate of hatching was also improved by inclusion of one of these substances into the control diet. These results suggested that the effective components in raw krill for improving the quality of red seabream eggs are both phosphatidyl choline of the polar lipid fraction and astaxanthins of the polar lipid fraction. Therefore, the principal factors aiding the reproduction of red seabream are the common factors between these substances, probably free radical scavengers.

Intergeneric hybridization in Sparidae: 1. Sparus aurata ♀ × Diplodus puntazzo ♂ and Sparus aurata ♀ × Diplodus vulgaris ♂

Eggs of gilthead sea bream ( Sparus aurata) were inseminated by the sperm of sharp-snout sea bream ( Diplodus puntazzo) and common two-banded sea bream ( Diplodus vulgaris). Under controlled conditions, at 19.5°C, embryogenesis and yolk sac resorption in both intergeneric combinations took less time than embryogenesis and yolk sac resorption in Sparus aurata. Survival and growth of larvae of Sparus aurata, Sparus aurata ♀ × Diplodus puntazzo ♂ and Sparus aurata ♀ × Diplodus vulgaris ♂ were established during yolk sac resorption. During the active feeding period, between days 6 and 30 after hatching, neither growth nor survival differed significantly among the studied species and crosses. Sparus aurata ♀ × Diplodus puntazzo ♂ larvae grew slightly but not significantly faster.

Effect of broodstock diets on lipid classes and their fatty acid composition in eggs of gilthead sea bream (Sparus aurata L.)

Total lipid content, total lipid fatty acids, lipid classes and their fatty acid compositions were studied in eggs of gilthead sea bream from two different broodstocks.The two broodstock diets used had the same total lipid content, but differed with respect to their fatty acid levels. The lipid class composition of eggs from different origins was not significantly different. The predominant polar lipids were phosphatidylcholine, phosphatidylethanolamine and sphingomyelin, and the main neutral lipid classes were cholesterol esters and triacylglycerols.The fatty acid composition of total lipids and main lipid classes in the two groups of eggs showed marked differences, reflecting the influence of fatty acid levels in the broodstock diets.

The effects of the water soluble fraction of iraq crude oil on eggs, larvae and postlarvae of gilthead sea bream, Sparus aurata linnaeus 1758

A study of the effects of the water soluble fraction of Iraq crude oil on eggs, larvae and postlarvae of gilthead sea bream, Sparus aurata is presented. The water soluble fraction of Iraq crude oil greatly affects eggs of gilthead sea bream, causing mortality, deformities, narcotic effects and reduced motility. Larvae in all water soluble fraction concentrations died after 72 h. At the start of exposure, growth and yolk sac resorption increase, but after 24 h both decrease compared to the controls. Of the early stages, postlarvae seem to be most resistant to the water soluble fraction of Iraq crude oil.

Improvement of quality of red sea bream eggs by feeding broodstock on a diet containing cuttlefish meal or on raw krill shortly before spawning.

Red sea bream broodstock were fed on various diets of different nutritional quality for either 26 days or shortly before spawning to clarify the effect of the duration of the period over which diets are fed on spawning and egg quality.The percentage of buoyant eggs in the control group receiving the white fish meal diet was 42.7%, slightly lower than that hitherto obtained by the diet. Addition of 200mg of DL-α-toco-pheryl acetate to the diet elevated the value to 77.9%. The value was also effectively improved by replacement of cuttlefish liver oil with krill oil extracts. Substitution of cuttlefish liver oil by corn oil resulted in deterioration of egg quality. In the eggs produced by the broodstock fed on a diet containing cuttlefish meal as a protein source, percentage of buoyant eggs was as high as 98.4%. Feeding broodstock with frozen raw krill after the fish had previously been fed on a diet fortified with vitamin E for 26 days also resulted in elevation of the percentage of buoyant eggs. A similar improvement was also observed in a group given a diet containing corn oil, the original value was 30.6% it was elevated to 91.7% by feeding frozen raw krill shortly before spawning.Consequently, total quantity of fish seed produced by each experimental group calculated from the number of buoyant eggs, hatchability and abnormality in both eggs and hatched larvae was highest in the cuttlefish meal group, followed by the frozen raw krill groups. Thus in fishes like red sea bream which can accept diet actively even during spawning, the quality of diets given to broodstock even shortly before spawning becomes very important for their reproduction.

Metabolism of dietary carotenoids in eggs of red sea bream

Abstract 1. 1. Transfer of dietary carotenoids into eggs was examined by a feeding experiment of red sea bream broodstock. 2. 2. Levels of carotenoids incorporated in the eggs were approximately 60 μg/100 g irrespective of amounts and kinds of carotenoids supplemented to the diets. 3. 3. Only keto and non-esterified carotenoids were detected in the eggs. 4. 4. Canthaxanthin was transferred into eggs but not β-carotene. Astaxanthin esters were converted largely to non-esterified astaxanthin and partly to doradexanthin. It was presumed that idoxanthin present in the eggs was derived from non-esterified astaxanthin in the diets.