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1.
The aim of this study was to clarify further the relationship between dietary keto-carotenoids (canthaxanthin and astaxanthin) and reproductive performance in female rainbow trout. Three experiments were undertaken in three successive breeding seasons. In addition to a control diet, fish were fed a canthaxanthin-supplemented diet (200 mg canthaxanthin kg−1 feed, designated as 6mC200) for 6 months prior to spawning (experiment A); the same diet as in A but for either 3 months (3mC200) or 6 months (6mC200) before spawning (experiment B); diets with one of two levels of astaxanthin supplementation, 50 mg (6mA50) or 100 mg (6mA100) kg−1 feed, or a diet with 100 mg canthaxanthin kg−1 feed (6mC100) fed for 6 months (experiment C).
There was no significant influence of carotenoid supplementation on either the frequency of maturing females or the date of maturation. The number of ova per kg of female body weight averaged 2700 and did not vary significantly among fish fed the different diets. Across experiments A, B and C there was no significant difference in egg and larval survival among fish fed carotenoid-supplemented and control diets. In experiment A, 6mC200 females produced smaller eggs than controls but this result was not confirmed in experiments B and C. In general, eyed egg yield appeared partly dependent upon egg size. Alevin weight was also correlated with egg weight. The growth test conducted on fingerlings from experiment B failed to provide any evidence of an effect of feeding carotenoid supplemented diets to the female parent. Pigment analyses conducted on alevins revealed that canthaxanthin fed to the female parent was transferred into the eggs and therefore to the larvae, although canthaxanthin was metabolized within a few weeks after hatching.  相似文献   

2.
ABSTRACT: The effect of an n-3 essential fatty acid (EFA) -deficient diet on spawning and on the lipid and fatty acid contents of eggs, semen and livers of rainbow trout Oncorhynchus mykiss was investigated. Fish were split into two groups and fed either of two diets for a period of 4 months prior to the start of the spawning season. The control group was fed a commercial diet, containing n-3 EFA, whereas the experimental group was fed an n-3 EFA-deficient diet. Fish were 3 years old at the time of spawning. Eggs and semen were stripped off five females and five males from each diet group and cross-fertilized. Two of the five males fed the deficient diet showed a lower sperm motility, resulting in slightly lower mean hatching rates when crossed with eggs of either group. Higher lipid contents in the EFA-deficient diet were reflected in the egg and semen lipid contents, whereas the lipid contents of male livers of both diet groups were higher than those of female livers. In livers and eggs, the main polar lipid was phosphatidylcholine accompanied by phosphatidylethanolamine in sperm polar lipids. The non-polar lipids of eggs were mainly triacylglycerols but in livers and semen, free fatty acids and free sterols were more abundant. Essential fatty acids, namely n-3 highly unsaturated fatty acids and linolenic acid, were generally lower in eggs, semen and livers sampled from the EFA-deficient diet group. These results indicate that the fertilization, eyed and hatching rates obtained from crossings with males fed the EFA-deficient diet were slightly lower because of the dietary effect on sperm motility. Moreover, lipids of eggs, semen and livers of male and female rainbow trout were influenced greatly by their dietary availability.  相似文献   

3.
Cultivated Atlantic cod (Gadus morhua) entering their first year of gamete maturation were fed diets with different levels of arachidonic acid (ARA) and eicosapentaenoic acid (EPA) for 6.5 months prior to commencement of spawning. Gravid females were stripped three times: at the beginning, peak and end of spawning. Lipid composition and egg and larval quality of 34 family crosses were investigated. Results indicated that ARA uptake into eggs from broodstock diet was highly efficient achieving proportions of ARA up to 84% higher in eggs than in the diet. EPA was 42–76% higher, and DHA was 155–173% higher in eggs than in diets. Cod fed the diet with the lowest EPA/ARA ratio had the greatest egg production. Eggs from fish on a diet with high ARA level had significantly higher fertilization and hatching success than those fed low levels of ARA. This diet produced on average 71 viable eggs g?1 female compared with 32.5 and 4 eggs in diet B and C, respectively. Furthermore, larval survival until 8 days posthatch was higher in diets with lower ARA levels. The combined results showed that ARA dietary supplementation and low EPA/ARA ratio yielded a greater number of viable larvae kg?1 female.  相似文献   

4.
SUMMARY: This study was carried out to investigate the effects of dietary squid meal or a combination of squid meal and krill meal as part of the protein source in dry pellets on the spawning of striped jack Pseudocaranx dentex . Five months prior to spawning, 7-year-old fish were divided into three groups of 10 fish each (male : female ratio, 5 : 5). The control group was fed a raw fish mix (RF) and the other two groups were fed either steam-dry pellets with squid meal replacing 50% of their fish meal (fs-DP) or steam-dry pellets containing equal proportions of fish, squid and krill meals (fsk-DP). Feeding was carried out once every other day in 5 × 5 × 5 m floating net cages and the fish were transferred to 65 m3 indoor tanks for spawning. Eggs and yolksac larvae produced were evaluated for their quality and those obtained during the first 2 weeks of spawning were sampled for chemical analysis. The fish had an average bodyweight of 3.5 ± 0.4 kg at spawning. Although egg production of the RF group was significantly higher ( P < 0.05) than that of the dry pellet groups, the fs-DP group produced the best quality eggs with higher fertilization and hatching rates. The fsk-DP group had the lowest egg production and quality. Lipid classes and fatty acid compositions of eggs and yolksac larvae were dependent on the broodstock diets. These results show that the combination of fish meal and squid meal in dry pellets for striped jack improved egg quality but not production whereas the combination of fish meal, squid meal and krill meal was not effective.  相似文献   

5.
SUMMARY: This experiment was conducted to investigate the effect of astaxanthin supplemented steam-dry pellets on the spawning of striped jack Pseudocaranx dentex . Five months before spawning, 7-year-old fish were divided into three groups, each consisting of five females and five males. The control group was fed a raw fish mix (RF) and the test diets consisted of steam-dry pellets (DP) and steam-dry pellets supplemented with 10 p.p.m. astaxanthin (a-DP). Feeding was carried out once per day, three times a week in floating net cages. The RF and the a-DP groups produced more than three times the amount of eggs produced by the DP group. The buoyancy, fertilization, and hatching rates were higher and similar for the RF and the DP groups. Total lipid contents of the diets, eggs, and larvae were similar among the groups. Highly unsaturated fatty acids (n-3 HUFA) and polar and non-polar lipids in eggs and larvae were also related to their dietary availability. These results indicate that astaxanthin, due to its various physiological functions, improved the condition of the broodstock and enhanced total egg production but not egg quality as striped jack do not incorporate carotenoids into their eggs. Therefore we confirm that the nutritional quality of diets given to striped jack prior to spawning plays a fundamental role in egg production, quality and egg composition.  相似文献   

6.
A feeding experiment was conducted on gilthead seabream (Sparus aurata) broodstock to investigate the incidence of n-3 highly unsaturated fatty acids (n-3 HUFA) dietary deficiencies on the lipid composition of female liver, gonads and eggs, in relation to spawning quality. Broodstock were fed a control (C) diet or a n-3 HUFA deficient (D) but linolenic acid rich diet. After 20 weeks of feeding, the results showed that levels of total neutral (TNL) and total polar (TPL) lipids of female gonads and eggs were independent of diet. However the fatty acid composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) of female liver, gonads and eggs in the two groups of fish showed marked differences, reflecting the influence of fatty acid levels in the broodstock diets. This influence was even higher in TNL than in the phospholipid classes examined. In fish fed n-3 HUFA deficient diet, fatty acid composition of TNL of female gonads and eggs reflected the diet more than liver. A higher egg production in broodstock fed C diet (1.8% n-3 HUFA in diet) was extended to spawning quality such as percentages of fertilised and hatched eggs.  相似文献   

7.
This study investigated the effect of dietary arachidonic acid (AA) in broodstock of Japanese flounder on subsequent egg and larval quality. Diets with similar proximate composition and n-3 HUFA level, but with different AA levels (0.1%, 0.6% and 1.2% of diet), were fed to the broodstock from 3 months before and during the spawning season. Spawning was observed from March to May. Total egg production over the spawning season was highest in fish fed the 0.6% AA diet and lowest in fish fed the 1.2% AA diet. All parameters measured as egg quality (percentage of buoyant eggs, hatching rate, larval survival and normality of larvae.) were highest in fish fed the 0.6% AA diet. AA content in eggs proportionally increased with the dietary AA level. EPA content of polar lipids of eggs had a negative correlation with the AA level in diets whereas the DHA content was independent of dietary AA. The results of this study indicate that a supplement of AA at 0.6 g/100 g diet improved the reproductive performance of Japanese flounder, but a higher level of AA (1.2 g/100 g diet) negatively affected both egg and larval quality due to a potential inhibitory effect on EPA bioconversion.  相似文献   

8.
We investigated the effect of high levels of n−3 highly unsaturated fatty acids (n−3 HUFA) in broodstock diet on egg quality and chemical composition of eggs of Japanese flounder. The broodstock were fed diets containing three levels of n−3 HUFA (2.1%, 4.8% or 6.2%) 2 months before and during the spawning period. No significant difference was found for weight gain of broodstock among the treatments. Egg production was highest in fish fed the highest level of n−3 HUFA. However, egg quality parameters, such as percentage of buoyant eggs, hatching rate and percentage of normal larvae, were significantly higher in the group fed the lowest n−3 HUFA diet. The fatty acid composition of eggs was influenced more markedly in the neutral lipid fraction than in the polar lipid fraction by dietary n−3 HUFA levels. Arachidonic acid (AA; 20:4n−6) and egg quality parameters both decreased with increasing dietary n−3 HUFA levels. The results suggest that a high level of n−3 HUFA in broodstock diet negatively affects egg quality of Japanese flounder.  相似文献   

9.
《水生生物资源》1999,12(1):11-22
Duplicate groups of first-feeding (4-5-d-old) Tilapia zillii (Gervais) were maintained on two feeding regimes (high and low ration size) for a total period of 550 d (~ 17 months) in environmentally-controlled aquaria. Differences in mean individual fish weight were evident between fish fed the different ration sizes after just 3 months, though these differences were not statistically significant until day 180. Thereafter, fish maintained upon the higher ration were significantly larger than fish fed a reduced ration. Mortality in high ration fish over the course of the experiment was ~60 % compared to ~88 % in low ration fish. Mortality in both treatment groups was most pronounced during the first three months (particularly during the first 30 d) but was much reduced there-after. Spawning trials undertaken from day 450 onwards indicated that there was no significant difference between the two ration groups in terms of spawning periodicity over a discrete time period of 60 d. Mean total fecundity was significantly higher in fish on high rations though mean egg diameter and gonadosomatic index remained unchanged. Adjustment of spawning data to a common maternal fish size using one-factor ANCOVA failed to detect significant differences between the two ration levels in terms of either mean total fecundity or mean egg diameter. Stereological analysis of plastic-embedded ovarian tissue revealed that the ovaries of low ration fish possessed significantly more stage 2 and 3 (early and late perinucleolar) oocytes and significantly less stage 6/7 (late-vitellogenic/maturing) oocytes than the ovaries of fish fed the higher ration. No significant differences were detected between the two rations in terms of ovarian atresia. It is suggested that under prolonged food restriction, female T. zillii sacrifice somatic growth such that reproductive investment can be maintained.  相似文献   

10.
Egg quality, those characteristics of the egg that determine its capacity to survive, is a significant problem for many species of fish currently being farmed. Little is known about the determinants of egg quality and there is little agreement regarding reliable methods for its assessment. To be of practical benefit, assessments should be simple to perform and should be carried out as early in development as is possible. Fertilization rates are often used as measures of quality. For the Atlantic halibut Hippoglossus hippoglossus, fertilization rate and assessments of cell symmetry at early cleavage stages provide reasonable indicators of quality. Regardless of assessment method, it is strongly recommended that performance data from all batches of each broodfish be examined when surveying the overall quality of a stock. The misleading effects of pooling such information are demonstrated for a rainbow trout Oncorhynchus mykiss broodstock. Although a large number of factors have been implicated as possible determinants of egg quality, only 1) bacterial colonization of the eggs, 2) nutritional status of the broodfish and, 3) overripening, the process of aging that occurs when eggs are retained within the broodfish after ovulation, have been clearly shown to affect egg quality. The effect of overripening on fish egg quality is discussed in detail. Species-specific differences in the time scale of overripening are pointed out and related to spawning strategy and water temperature. Rainbow trout eggs and those of other salmonids should be fertilized within approximately one week of ovulation. Overripening proceeds much more rapidly in warm water species, e.g., tilapia eggs must be fertilized within an hour or so of ovulation. Egg viability also decreases rapidly for batch spawning species. Fertilization data are presented for Atlantic halibut demonstrating that egg quality decreases 4–6 h after ovulation. The rate of overripening was comparable for eggs held in vitro in ovarian fluid to those retained within the ovarian lumen. These halibut data, combined with information from other marine and freshwater fish, indicate that overripening is a significant determinant of egg quality for many if not all fish.  相似文献   

11.
Two-year old rainbow trout females were fed diets containing 0, 30, 110, 220, 440 and 870 mg kg-1 ascorbyl-2-monophosphate Mg+ salt (groups 1, 2, 3, 4, 5, and 6, respectively) from August until March. At the time of spawning (February–March) blood was sampled and the ovulating females were hand stripped. Estradiol (E2) and testosterone (T) concentrations in plasma, and ascorbic acid (AA) concentrations in plasma and eggs were determined. The mean plasma concentrations of T were higher in group 4, 5, or 6 than in group 2 or 3 (p < 0.05). Moreover, the average plasma concentration of T in fish fed the diets with AA level below National Research Council (NRC) recommendations (groups 1, 2 and 3) was significantly lower (p<0.01) than the average plasma concentration in fish fed diets with AA level above NRC recommendations (groups 4, 5, and 6). These data are consistent with the hypothesis that AA can influence production of steroids in female rainbow trout.Corresponding author  相似文献   

12.
The purpose of this study was to investigate the possibility of producing tetraploid fishes. Eggs of salmon (Salmo Salar) and rainbow trout (Salmo gairdneri) were treated with concentrations of cytochalasin B ranging from 1 μg/ml to 100 μg/ml for varying periods of time. All treated groups had higher death rates than untreated controls. If the treatment was started immediately after fertilization and before the eggs had swollen all eggs died. The highest frequency of mosaic embryos and polyploid cells was obtained when the treatment started 35–70 h° (hour-degrees) after fertilization and lasted until about the 4-cell stage of development. A dose of 10 μg/ml of cytochalasin B gave the most satisfactory results. This concentration was used for further work. Two batches of 6000 salmon eggs and several groups of rainbow trout eggs were treated and hatched. The hatchability was generally low while the control group had a normal hatchability. If some of the treated fish are eventually found to be tetraploids and fertile, they will be used to produce triploid offspring by crossing with normal diploid fish.  相似文献   

13.
This study was conducted to determine the optimum phospholipids: highly unsaturated fatty acids (PL/HUFA) ratio in maturation diets for female Chinese mitten crab, Eriocheir sinensis broodstock. Five isolipidtic and isonitrogenous diets were formulated to contain different amounts of pork lard, fish oil and soy lecithin with resulting PL/HUFA levels (%dry weight) of 1.4/0.3 (Diet 1), 1.6/2.5 (Diet 2), 2.3/2.0 (Diet 3), 3.8/1.5 (Diet 4) and 5.1/0.8 (Diet 5). Diet 1 lacked supplemental fish oil and soy lecithin and served as the control. Each of the five formulated diets was fed to a total of 150 female crabs for a period of 7 months. All diet treatments were triplicated with 50 crabs stocked in a pond as a replicate. After 6 months, male crabs were introduced into the ponds where females were kept, mating, spawning and egg hatching (in seawater) occurred in the following month. The nutritional value of various formulated diets was assessed based on survival, gonadosomatic index (GSI), egg production per female, fecundity (eggs/g female weight) of the females fed those diets and egg and larval (newly hatched zoea I larvae) quality.Females fed Diet 1 had the lowest GSI, egg production per female and fecundity while no significant difference were found for survival, hepatosomatic index (HSI) and the percentage of female spawned among the diet treatments (P > 0.05). Although there were no significant differences in egg diameter, egg wet or dry weights among all treatments (P > 0.05), the highest and the second highest proportions of essential fatty acids (EFA), i.e. 20:5n-3 (EPA), 22:6n-3 (DHA) and HUFA were found in the eggs produced by the females fed Diet 3 and Diet 2, respectively. Statistical analysis showed that EPA, DHA and HUFA in eggs produced by females fed Diet 3 were significantly higher than those from the other treatments (P < 0.05). Meanwhile, zoea I larvae from crabs fed Diet 3 had significantly larger carapace length than those from the other four treatments (P < 0.05). The zoea I larvae from crabs fed Diet 2 and Diet 3 also showed generally better tolerance to starvation and osmotic shock.In conclusion, our results indicated that diet included levels of PL/HUFA around 1.6/2.5 or 2.3/2.0 (% dry weight) fed female E. sinensis broodstock supported increased fecundity and elevated level of HUFA in egg, which in turn resulted in improved overall quality of newly hatched larvae.  相似文献   

14.
Commercial intensive fry production of Atlantic cod will be dependent on production of viable eggs independent of season. This can only be done by manipulation of maturation by photoperiod, but little is known about potential effects on egg characteristics and larval viability. In two cod broodstocks, maturation was successfully advanced or delayed 6 months compared with normal spawning season (March–April) by manipulation of photoperiod. The advanced broodstock spawned both in spring and autumn the same year. In two of the spawning tanks during autumn, ambient temperature was reduced after reaching 13.7°C during the first half of the spawning period. Egg quality and viability were monitored, and several egg batches were incubated, hatched and start‐fed for examination of growth and survival. Temperatures above 9.6°C resulted in significant reductions in fertilization and normal egg development. Concurrently, fractions of dead and unfertilized eggs increased with elevated temperature. Actual relative fecundity was not affected by temperature. Egg characteristics improved when temperature was controlled and lowered below 9.6°C. Occurrence of irregular spawners suggests that handling of broodstock fish should be avoided during maturation and spawning. Cod larvae originating from eggs of the advanced or delayed broodstocks were successfully reared beyond metamorphosis. Survival was 9.0–46.6% and 29.3% in green and clear water respectively. Survival correlated with both initial and average feeding conditions, but growth rate did not correlate with either of survival and feeding conditions. Specific growth rates (8.3–13.6% day−1) is comparable with other intensive rearing trials with cod, but were lower than reported from nature‐like systems.  相似文献   

15.
The reproductive performance of three domesticated rainbow trout broodstocks spawning at 2 years of age was analysed using data collected over a period of 5 years. Data were collected for post-spawning body weight, volume of eggs spawned, egg size, egg number and fertility to the eyed egg stage. There were significant differences among the stocks attributable to both genetic and environmental causes. In addition, there were marked differences between year-classes, isolated from each other due to 2-year spawning. The differences appeared to be genetic in origin and demonstrated the effect of sampling the original parents.Heritabilities estimated from full-sib comparisons indicated male weight was more influenced by environmental stress at spawning than was female weight. Heritability estimates for egg volume, egg size and egg number ranged from 0.05 to 0.76 for individual stocks, but when averaged for the three stocks the range was from 0.32 to 0.52. Egg size was found to have the lowest heritability of the three traits. The heritability of fertility was found to be low and was the lowest for the stock with the poorest fertility.Genetic and phenotype correlations among the traits were also estimated. The relationship between body weight and egg volume and size were both positive as was that between egg volume and egg size. It was determined that egg volume was the principal determinant of egg number and that the relationship of number to size could be negative. The latter evidence was obtained by artificially adjusting the egg production traits to a constant female body size. The result suggested that females that produce larger numbers of eggs are likely to produce smaller eggs unless the change is associated with a marked increase in body weight. It is recommended that selection for egg size be included in all selection programs and that egg number be ignored in any selection program designed to increase body size.  相似文献   

16.
ABSTRACT: This study was conducted to investigate the effect of squid meal and astaxanthin in dry pellets on the spawning performance of striped jack. Two groups of 8-year-old fish with an average bodyweight of 3.5 ± 0.4 kg were used. The control group was fed a raw fish mix (RF) and the experimental group was fed steam dry pellets (as-DP) containing 10 p.p.m. astaxanthin and squid meal, the latter replacing half the fish meal. Each group was fed once a day, three times a week in floating net cages for a period of 5 months. Seven females and seven males were selected from each group and transferred to 65 m3 indoor concrete tanks for spawning, where they were kept at optimum spawning conditions (22°C) for 1 month. The average bodyweights of selected fish were 3.8 ± 0.5 kg and 3.8 ± 0.6 kg for the RF and as-DP groups, respectively. Both groups spawned a total of 18 times and the mean total egg production and egg quality, measured in terms of buoyancy, fertilization and hatching rates, showed no significant differences ( P > 0.05) between groups. Total larval production was 679.9 × 103 and 678.1 × 103 larvae/kg-female for the RF and as-DP groups, respectively. These results show that the combination of astaxanthin and squid meal in dry pellets for striped jack broodstock improved the overall spawning performance to a level similar to that of fish fed on RF.  相似文献   

17.
The effects of dietary vitamin C on maturation and egg quality of cod Gadus morhua L. have been investigated. The broodstock groups were fed three different levels of vitamin C mixed into a commercial dry pellet. The experimental feeding started three months prior to the spawning season. Naturally spawned eggs were collected and analyzed with regard to viability, biochemical composition and physical characteristics. Differences in free amino acid profile, egg strength and neutral buoyancy were found, whereas no effects on vital parameters, such as fertilization rate and survival rate, were detected.  相似文献   

18.
The effects of dietary protein and energy level on spawning performance of Nile tilapia broodstock and hatchability of their eggs were studied. Nine diets containing three protein (30, 35 and 40%) and three energy (14.6, 16.7 and 18.8 MJ GE/kg) levels were prepared. The diets were fed to duplicate groups of broodfish (average weight of 60.5 ± 4.6 g for males and 39.4 ± 3.1 g for females) at 2–3% of their body weight, twice a day, for 150 days. At low protein level (30%), time to first spawning was significantly longer than at 35 and 40% protein levels, and increased with increasing dietary energy (decreasing protein-to-energy (P/E) ratio). At 35 and 40% protein levels, time to first spawning was not affected by dietary energy. Inter-spawning intervals (ISI) showed irregular patterns in relation to dietary protein and energy, however, at 40% protein the females tended to spawn at shorter intervals, regardless of dietary energy. Spawning performances, including total number of spawnings per tank, number of spawnings per female, absolute fecundity and average number of eggs per spawn, were all significantly lower (P < 0.05) at 30% CP than at higher protein levels. At all protein levels, increasing dietary energy from 14.6 to 18.8 MJ GE/kg (and decreasing P:E ratio) resulted in a significant decrease in fish fecundity. Egg size was not significantly affected by dietary protein and energy. At all energy levels, egg hatchability increased with increasing dietary protein levels (P < 0.05). Eggs produced from broodstock fed 30 and 35% CP, exhibited significantly lower hatchability (P < 0.05) and needed less time for hatching and yolk-sac absorption, and resulted in lower larval length than those fed a 40% protein diet. However, increasing energy level at each dietary protein level did not significantly affect these parameters. These results revealed that the best spawning performance of Nile tilapia broodstock reared in a recycling system was achieved at 40% dietary protein and 16.7 MJ GE/kg, with a P/E ratio of 23.6 g/MJ.  相似文献   

19.
This study investigated supplemental effects of vitamin A in diet on reproduction of Japanese flounder Paralichthys olivaceus (T & S). Broodstock were fed either a non‐supplemented diet (control diet; CD) or a vitamin A‐supplemented diet (supplemental diet; SD) 1 month before and during the spawning season. Both dietary groups began to spawn in mid‐January. At the beginning of spawning, no notable differences were found in spawning or egg quality between treatments. Egg production of the CD broodstock began to decrease from mid‐April and spawning stopped in late May, whereas the SD group continued to spawn until the end of June. Buoyant egg rate of the CD group was lower than that of the SD group throughout the spawning period. Hatching rate was not different between the CD and SD groups. The percentage of normal larvae in the CD group was significantly lower than in the SD group. It is concluded that a low vitamin A content in the diet has some negative effects on reproduction of flounder. The importance of supplementation of vitamin A in broodstock diet of the Japanese flounder is suggested.  相似文献   

20.
The influence of broodstock dietary lipids on egg quality and egg fatty acid composition throughout the spawning season of gilthead seabream was investigated. For this purpose, the fish were fed for 7 months either a control diet (diet C) or a diet deficient in n−3 highly unsaturated fatty acids (n−3 HUFA) but rich in both oleic (18:1n−9) and linolenic (18:3n−3) acids (diet D). Eggs spawned by both groups of fish were sampled at the beginning, middle and end of the spawning season and the fatty acid composition of their neutral (NL) and polar lipids (PL) determined. In the early season, percentages of fertilized and hatched eggs, relative proportions of NL and PL as well as their fatty acid compositions, were not affected by the lipid composition of the broodstock diet. However, the eggs spawned during the middle and late seasons showed marked differences among the two groups of fish, clearly reflecting the influence of dietary fatty acids. This influence was more evident in the neutral lipid fraction than in the polar lipids. No correlation was found between the number of buoyant eggs and eicosapentaenoic (20:5n−3, EPA), docosahexaenoic (22:6n−3, DHA) fatty acids or total n−3 HUFA contents in egg phospholipids. However, a negative correlation was detected when percentages of fertilized eggs were compared with the levels of 18:1n−9, 18:3n−3 and with the ratio 18:1n−9/n−3 HUFA present in the phospholipids. Our results indicate the importance of maintaining not only the level of n−3 HUFA in egg membrane phospholipids, but also the balance between n−3 HUFA and other fatty acids such as 18:1n−9 and 18:3n−3, in order to obtain a high spawning quality.  相似文献   

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