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1.
R. M. Rideout E. A. Trippel M. K. Litvak 《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):215-228
Haddock, Melanogrammus aeglefinus, is a serial spawning, marine gadid characterized by low survivorship during the early life history stages. The potential for predicting future survival to hatching based on cleavage patterns of early embryos (8–32 blastomere stages) was investigated in order to improve efficiency of early rearing practices. In 2001, data from 36 egg batches (>95% fertilization) suggested that hatching success was inversely related to the percentage of embryos with abnormal cleavage. Mean percentage of normal cleavage did not differ throughout the spawning season but variability was much higher for embryos from early and late batches than those collected during the middle of the spawning season. In 2002, abnormalities in blastomere cleavage for 12 egg batches were further categorized as (1) asymmetric blastomere arrangement, (2) inequality of blastomere size, (3) poor adhesion between blastomeres and (4) poor definition of blastomere margins. Results suggested that all four abnormalities were co-occurring, which prevented negative effects on hatching success from being attributed to a single abnormality. Incubation of embryos with only one type of cleavage abnormality suggested that low adhesion between blastomeres significantly reduced embryo viability, while asymmetry in blastomere arrangement did not. However, because cleavage abnormalities tended to co-occur, hierarchical multiple regression revealed that asymmetry could be used to accurately predict hatching success, even if reduction in embryo viability was due to abnormalities other than asymmetry. Analysis of additional cleavage abnormalities suggested that complete separation between blastomeres was indicative of a very poor egg batch and resulted in little or no hatching, while cellular outcrops had no negative effect on hatching success. Information from detailed studies such as these could be used to predict hatching success of individual egg batches, allowing time and resources to be allocated more efficiently in hatcheries. 相似文献
2.
Egg yolk nutritional constituents as indicators of egg quality in Atlantic halibut (Hippoglossus hippoglossus L.) 
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下载免费PDF全文 Variation in oocyte quality affects sustainability of finfish aquaculture products including Atlantic halibut (Hippoglossus hippoglossus L.). To have an insight into role of major egg yolk constituents in the oocyte quality, egg fatty acid (FA), amino acid (AA) and folate contents were related to normal blastomere symmetry, and fertilization and hatching success. Significant correlations were found between dihomo‐γ‐linolenic acid (DGLA, 20:3n6), palmitic acid (PA, 16:00) and docosapentaenoic acid (DPA, 22:5n3), and normal blastomere symmetry and survival success. Egg concentrations of myristic acid (MA, 14:0), oleic acid (OA, 18:1n9), stearidonic acid (SA, 18:4n3) and eicosadienoic acid (EDA, 20:2n6) explained 56 % variation in fertilization success. OA and EDA explained 70 % of variation in blastomere symmetry. Palmitoleic acid (POA, 16:1n7) and linolenic acid (LNA, 18:3n3) concentrations explained 57% of variation in hatching success. Egg valine concentrations correlated with fertilization rates, and aspartic acid and leucine correlated with normal blastomere symmetry. Alanine and valine concentrations explained together 45% of variation in fertilization. Glutamic acid and tyrosine concentrations explained 68% of variation in normal blastomere symmetry while serine, arginine and valine explained 36% of variation in hatching. These FAs and AAa may be potential indicators of oocyte quality in Atlantic halibut. 相似文献
3.
Fariborz Ehteshami Annie Christianus Hossein Rameshi Sharr Azni Harmin Che Roos Saad 《Aquaculture Research》2011,42(4):613-622
Black‐lip pearl oyster, Pinctada margaritifera broodstock was collected from the wild. Egg production, hatching rate and larval development were compared between oysters induced to spawn within 2 days after collection in the wild (T1), oysters fed a pure microalgae diet during 24 days before spawning (T2) and oysters fed the same microalgal diet in which 10% of the algae were replaced with 2 μm polyunsaturated fatty acid (PUFA)‐rich microspheres (T3). Administration of lipid microspheres resulted in larger sized eggs, a higher percentage of D‐larvae and larger sized 48‐h‐old larvae (P<0.05). The total and neutral lipid contents of the gonad increased after oysters were fed with microalgae only or with supplementary diet. The major neutral and polar fractions of saturated fatty acid (SFA) were 16C and 18C fatty acids, and not influenced by the diet (P>0.05). The gonads of oysters fed supplementary PUFA contained more docosahexaenoic acid (DHA) and less monounsaturated fatty acids. Higher level of DHA in gonads of T3 was associated with oogenesis and embryogenesis success. The n‐3/n‐6 ratio in the neutral lipid fraction provides a good indication of the spawning condition and predicting egg size and hatching rate. 相似文献
4.
G. Gimnez A. Estvez F. Lahnsteiner B. Zecevic J.G. Bell R.J. Henderson J.A. Piera J.A. Sanchez-Prado 《Aquaculture (Amsterdam, Netherlands)》2006,260(1-4):232-243
The spawning quality, in terms of hatching rate, larval mortality at 3 and 5 days post-hatching (dph) and day of total mortality of two broodstock groups of common dentex was evaluated for 1 month in 2005. Several biochemical parameters including total lipid content, lipid class and fatty acid composition, carbohydrate content and metabolic enzyme activities were analysed in all the egg batches collected. Comparison was carried out between low- (mortality at 3 dph higher than 35%) and high-quality (mortality at 3 dph lower than 10%) batches. No differences were observed in lipid content and/or lipid class and fatty acid composition although a slightly higher content of neutral lipids was detected in high-quality batches. However, significant differences were obtained regarding carbohydrate composition and the activity of enzymes such as alkaline phosphatase and pyruvate kinase being higher in low-quality egg batches. 相似文献
5.
We investigated if simplified routines based on blastomere morphology and fertilization success can be used as predictors of egg and embryo viability in Atlantic cod, and abnormal blastomere morphology is related to juvenile deformities. Egg morphology data from 312 families that were produced by hand stripping of gametes were used. Fertilized eggs from all families were separately incubated in 25 L incubators. Blastomere morphology and fertilization success were assessed at 16–32 cell stage. Embryo mortality was measured until hatch. Fertilization success showed a significant positive correlation with the proportion of normal blastomere and 74% of the variation in the incidence of blastomere abnormality was explained by fertilization success. Juvenile deformities were positively correlated with blastomere abnormality and 8% of the variation in juvenile deformities was explained by incidences of blastomere abnormality. To our knowledge, this is the first direct evidence showing that incidences of blastomere abnormalities may be related to cod juvenile deformities. Our results suggest that fertilization success and the occurrence of blastomere abnormalities could be easily adopted by commercial cod hatcheries for the early determination of egg quality. 相似文献
6.
Egg quality determinants in cod (Gadus morhua L.): egg performance and lipids in eggs from farmed and wild broodstock 总被引：1，自引：0，他引：1
Guillaume Salze Douglas R Tocher William J Roy & Derek A Robertson 《Aquaculture Research》2005,36(15):1488-1499
Lipids and essential fatty acids, particularly the highly unsaturated fatty acids, 20:5n‐3 (eicosapentaenoic acid; EPA), 22:6n‐3 (docosahexaenoic acid; DHA) and 20:4n‐6 (arachidonic acid, AA) have been shown to be crucial determinants of marine fish reproduction directly affecting fecundity, egg quality, hatching success, larval malformation and pigmentation. In Atlantic cod (Gadus morhua L.) culture, eggs from farmed broodstock can have much lower fertilization and hatching rates than eggs from wild broodstock. The present study aimed to test the hypothesis that potential quality and performance differences between eggs from different cod broodstock would be reflected in differences in lipid and fatty acid composition. Thus eggs were obtained from three broodstock, farmed, wild/fed and wild/unfed, and lipid content, lipid class composition, fatty acid composition and pigment content were determined and related to performance parameters including fertilization rate, symmetry of cell division and survival to hatching. Eggs from farmed broodstock showed significantly lower fertilization rates, cell symmetry and survival to hatching rates than eggs from wild broodstock. There were no differences in total lipid content or the proportions of the major lipid classes between eggs from the different broodstock. However, eggs from farmed broodstock were characterized by having significantly lower levels of some quantitatively minor phospholipid classes, particularly phosphatidylinositol. There were no differences between eggs from farmed and wild broodstock in the proportions of saturated, monounsaturated and total polyunsaturated fatty acids. The DHA content was also similar. However, eggs from farmed broodstock had significantly lower levels of AA, and consequently significantly higher EPA/AA ratios than eggs from wild broodstock. Total pigment and astaxanthin levels were significantly higher in eggs from wild broodstock. Therefore, the levels of AA and phosphatidylinositol, the predominant AA‐containing lipid class, and egg pigment content were positively related to egg quality or performance parameters such as fertilization and hatching success rates, and cell symmetry. 相似文献
7.
Abstract. Lipid class and fatty acid analyses were carried out on eight batches of pre-fertilized eggs of Atlantic halibut, Hippoglossus hippoglossus (L.). These batches were classified as ‘viable’ or ‘non-viable’ according to fertilization rate, blastomere symmetry and incubation success. The lipid class and fatty acid compositions were very similar between egg categories with exception of cholesterol which was shown to be significantly greater in the ‘non-viable’ eggs. Polar lipid classes predominated (67·1% and 67·0% of the total lipid for ‘viable’ and ‘non-viable’ egg batches respectively), with phosphatidylcholine (PC) being the major class (43·2% and 43·5%) and triacylglycerol (TAG) the main neutral lipid class (18·8% and 17·8%). Gas liquid chromatography of fatty acid methyl esters from the total lipid revealed no significant differences in fatty acid composition. The fatty acid profiles of viable egg batches showed five major fatty acids 16:0 (17·3%), 18:0 (4·8%), 18:1n-9 (9%), 20:5n-3 (119%) and 22:6n-3 (25·9%). The results are discussed in terms of the potential role of lipids as egg quality determinants in fish. 相似文献
8.
H. Furuita H. Tanaka T. Yamamoto N. Suzuki T. Takeuchi 《Aquaculture (Amsterdam, Netherlands)》2002,210(1-4):323-333
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.
野生与人工养殖牙鲆亲鱼不同组织脂肪酸的比较 总被引：6，自引：1，他引：5
为研究脂肪酸对牙鲆繁育性能的影响, 采用生物化学方法, 对野生和养殖牙鲆亲鱼肌肉、肝脏及卵中脂肪酸组成分别进行测定。结果表明: (1) 牙鲆肌肉、肝脏和卵中脂肪含量大小关系为肝脏>卵>肌肉。野生亲鱼肌肉和卵中脂肪含量显著低于养殖亲鱼(P<0.05), 肝脏脂肪含量与养殖亲鱼无显著差异; (2) 牙鲆亲鱼3种组织中均检测出21种脂肪酸。野生亲鱼肌肉中饱和脂肪酸(SFA)与养殖亲鱼无显著差异, 单不饱和脂肪酸(MUFA)显著低于养殖亲鱼(P<0.05)。肝脏和卵中SFA显著高于养殖亲鱼(P<0.05), MUFA与养殖亲鱼无显著差异; (3) 野生亲鱼肌肉、肝脏和卵中高不饱和脂肪酸(PUFA)的含量, 尤其是肝脏和卵中C20:5n-3(EPA)、C22:6n-3(DHA)的含量均显著低于养殖亲鱼(P<0.05), 但肌肉和卵中的C20:4n-6(ARA)含量明显高于养殖亲鱼(P<0.05); (4) 野生牙鲆亲鱼肌肉、肝脏和卵中n-3/n-6 PUFA及EPA/ARA显著低于养殖亲鱼(P<0.05), 肝脏中DHA/EPA显著高于养殖亲鱼(P<0.05), 但野生亲鱼肌肉和卵中的DHA/EPA与养殖亲鱼无显著差异。比较结果说明, DHA、EPA和ARA等PUFA是与牙鲆繁殖性能密切相关的重要脂肪酸。在牙鲆亲鱼养殖过程中, 除了提供牙鲆亲鱼足够的脂肪酸营养外, 也应注意各种脂肪酸, 尤其是PUFA中各种脂肪酸之间的添加比例, 从而保证亲鱼的繁殖性能及卵和仔鱼的质量。 相似文献
10.
11.
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
12.
Christopher D Bentley Wade O Watanabe Troy C Rezek & Pamela J Seaton 《Aquaculture Research》2009,40(16):1873-1883
Adult black sea bass Centropristis striata broodstock ( N =162) were fed three different dietary treatments: two commercially prepared diets with 45% protein and two different lipid levels (12% and 20%) (diets 1 and 2), and a diet of frozen Atlantic silversides Menidia menidia (SS, diet 3). Broodstock were held under controlled photothermal conditions and induced to spawn with an LHRHa pellet (72 μg kg−1 bw). Dietary lipid had pronounced effects on spawning performance and egg quality. Diet 3 (SS) produced a significantly ( P <0.05) higher fertilization success (22.4%) than diets 1 (0.6%) and 2 (4.8%). The hatching success of fertilized eggs was similar in all diets (range=40–58.6%), but only two spawns from diet 1 (12% lipid) yielded viable yolk-sac larvae (YSL). Diet 3 (SS) also produced significantly more YSL per female (21.8 × 103 ) than the diet 1 (0.3 × 103 ). Eggs from diet 3 (SS) contained a significantly greater proportion of n-3 series fatty acids, with docosahexaenoic acid (DHA) as the largest fraction. Eggs from commercially prepared dietary treatments contained significantly more n-6 fatty acids. The poor spawning performance of fish fed diet 1 (12% lipid) may be related to higher levels of linoleic acid and lower levels of DHA in the diet. 相似文献
13.
暗纹东方鲀卵子磷酸酶等生化指标分析与卵质评估 总被引：1，自引：0，他引：1
为了研究暗纹东方鲀卵子可发育能力与其生化指标的关系,用生化分析方法对暗纹东方鲀未受精卵子基本成分、磷酸酶活力、苹果酸脱氢酶(MDH)活力、唾液酸(SA)、氨基酸含量进行分析,同时用GC-MS方法对脂肪酸组成及相对含量进行检测,并对各物质变化规律与其孵化率的相关性进行分析。结果显示,酸性磷酸酶活力(ACP)、SA含量与孵化率显著相关,碱性磷酸酶(AKP)与孵化率显著负相关;C14:0与孵化率显著相关,并呈现递减趋势;ARA、DHA与孵化率均显著相关,并呈现先递增后递减的变化趋势;n-3脂肪酸、DHA与EPA之比、EPA与ARA之比均与孵化率存在显著相关。结果表明,磷酸酶、SA、脂肪酸等物质变化规律与卵子孵化率存在相关性,且ACP活力值在68.045~141.038,AKP活力值在2.298~7.241,SA含量在9.081~19.973,C14:0含量在0.485~0.658,ARA含量在1.371~2.498,DHA含量在13.838~18.469时,均可作为卵子孵化率不低于50%的参考指标,据此可在一定程度上反映暗纹东方鲀苗种繁育生产中所用卵子的可孵化价值,亦可作为参考指标对其卵子质量进行初步的客观评价。 相似文献
14.
高度不饱和脂肪酸对中国对虾亲虾的产卵和卵质的影响 总被引：18，自引：2，他引：16
用高度不饱和脂肪酸组成和含量不同的四种饲料饲养中国对虾亲虾以研究高度不饱和脂肪酸对中国对韪亲虾产卵及卵质的影响。试验采用脂肪酸组成模式不同的Ｔｉ鱼油,亚麻油,玉米油和猪油为脂肪源配制的饲料对产卵前的亲虾进行６０天的投喂试验,测定了不同脂及到脂肪酸组成的饲料对亲虾产卵量,孵化率和卵脂肪酸组成的影响,并经回归分析结果表明,卵脂肪中的２０：５ω３与产卵量,２２：６ω３与孵化率有相关关系,表明了ＥＰＡ,Ｄ 相似文献
15.
Gloria T Seaborn Theodore I J Smith Michael R Denson Abigail B Walker & David L Berlinsky 《Aquaculture Research》2009,40(6):656-668
Lipid content, lipid class and fatty acid compositions were determined in eggs from wild and captive black sea bass, Centropristis striata L., from northern (New England) and southern (South Carolina) regions to determine the effects of diet on egg composition and fertilization success. The formulated diets fed to the northern captive (NC) fish were higher in total lipids (22%) compared with the cut fish and squid diet fed to the southern fish (SC; 3.3% lipid) and had a higher relative amount of linoleic acid (LA) and lower relative amounts of docosahexaenoic acid (DHA) and arachidonic acid (AA). These dietary differences were broadly reflected in the egg lipid composition. The LA levels were higher in all lipid classes in eggs of NC fish while AA levels were lower. The DHA was higher in the major polar lipids (PL) (phosphatidylcholine and phosphatidylethanolamine) of SC eggs compared with NC. Compared with wild fish, both captive groups produced eggs with PLs richer in LA and lower in DHA and AA. Over all fish groups, fertilization success was directly correlated with levels of DHA and AA in the PLs and was inversely correlated with LA levels. 相似文献
16.
Chatham K Callan Charles W Laidley Ian P Forster Kenneth M Liu Linda J Kling Allen R Place 《Aquaculture Research》2012,43(5):696-705
This study was conducted to determine the effects of broodstock diet on flame angelfish (Centropyge loriculus) reproduction and generate baseline spawning performance (mean fecundity, egg fertilization, egg viability) and egg biochemistry data for this species. Sixteen flame angelfish broodstock pairs were maintained on one of three formulated diets or a raw diet (consisting of squid, shrimp, fish eggs and algae) to determine the effect of diet composition on the fecundity, egg fertilization rates and egg viability over a 7‐month period. Although all the diets supported similar mean spawn frequency and fecundity over the duration of the experiment, the mean fertilization rates and egg viability were significantly greater among pairs receiving the raw diet. Egg fatty acid composition was generally reflective of the maternal diet and similar to the values reported for other tropical species. In particular, dietary factors such as n‐3 highly unsaturated fatty acid and ARA level (which were elevated in the raw diet and eggs from fish receiving that treatment) are correlated with egg quality and are therefore worthy of future investigation. Because of the ease of conditioning, adaptability to varied formulated diets and continuous, sustained reproductive output, flame angelfish are an excellent model for examining the factors affecting marine fish egg and larval quality. 相似文献
17.
闽东海域银鲳亲鱼性腺发育后期脂类及脂肪酸蓄积特点 总被引：1，自引：0，他引：1
脂肪和脂肪酸是海水鱼类早期生长发育的重要结构物质和能量来源。亲鱼的脂肪和脂肪酸储备影响其繁殖性能和早期仔鱼的发育。为了获知银鲳亲鱼性腺发育后期脂类及脂肪酸蓄积特点,本研究采用氯仿甲醇法及气相色谱法定量检测了繁殖季节闽东海域野生银鲳亲鱼不同组织的总脂肪及脂肪酸含量。结果表明:亲鱼卵巢、精巢、肝脏和肌肉的总脂肪含量差异显著。卵巢、精巢、肝脏和肌肉的总脂含量分别为:35.76%,15.11%,22.07%和22.14%(占组织干重)。极性脂肪占总脂肪的比例在精巢中最高,其次为肝脏和卵巢,在肌肉中最低。性腺从Ⅳ期发育到Ⅴ期,雌鱼卵巢总脂肪和中性脂肪含量显著增加,雄鱼肌肉极性脂肪含量显著降低。中性脂肪中卵巢的20∶5n-3(EPA,2.25~3.87 mg/g)、22∶6n-3(DHA,6.71~13.03mg/g)和高不饱和脂肪酸(HUFAs,17.20~29.64 mg/g)含量最高,极性脂肪中精巢的EPA(0.38~0.27 mg/g)和DHA(3.12~3.59 mg/g)含量最高。性腺中n-3/n-6比值显著高于肝脏和肌肉中。随着卵巢发育,DHA等必需脂肪酸在雌鱼不同组织及同一组织不同脂肪类别之间存在转移现象。研究表明,银鲳亲鱼各组织的总脂肪含量、总脂肪组成及脂肪酸绝对含量(mg/g干物质)具有组织特异性,随着性腺发育,必需脂肪酸总体上表现为由肌肉和肝脏向性腺中转移,且性腺中脂肪酸的变化主要发生在中性脂肪中。 相似文献
18.
Rodolfo Ballestrazzi Simona Rainis Francesca Tulli Arianna Bracelli 《Aquaculture International》2003,11(3):289-299
Two hundred and twenty rainbow trouts (IBW: 700 g) were randomly allotted to four tanks, with a male/female ratio of 0.56. Fish were fed for 168 d with four experimental diets containing herring oil, cod liver oil and coconut oil with the following inclusion rates: diet A: 12-1-0% respectively; diet B: 6-1-6%; diet C: 0-1-12%; diet D: 0-0-13%. Irrespective of the dietary treatment, weight gains of broodstocks were high (> 3 g/d) and FCR below 2. No significant difference was observed concerning the total amount of eggs spawn, egg average weight (82.5 mg/egg) and lipid content (5.4 mg/egg). However, the fatty acid profile of eggs was significantly affected by the dietary treatments. The content of unsaturated fatty acids, particularly the n-3 fatty acid series (EPA and DHA) significantly decreased with increasing levels of coconut oil in the diet. 相似文献
19.
Batches of eggs (1 batch/female) from 17 rainbow trout in their first spawning season were stripped and reared separately, and the percentage which hatched and the percentage which reached the stage of first feeding were determined. The fertilised egg batches were analysed for egg wet weight, egg dry weight, chorion weight and levels in the eggs of free, bound and total lipid, precipitable protein, protein phosphorus, lipid phosphorus, calcium and iron. All determinations were made on single eggs, and six eggs from each batch were analysed for each variable. Results were expressed in absolute terms (as weight of component per egg) and as percentage of egg dry weight. Highly significant variations in all these aspects of egg composition were shown to occur between parent females. However, there was no significant correlation between the percentage of the original number of eggs which hatched and any one aspect of egg composition, except for a weak positive correlation (P<0.05) with the percentage of protein phosphorus in the eggs. Similarly, there was no significant correlation between the percentage of the original number of eggs which reached first feeding and any one aspect of egg composition except for weak positive correlations (P<0.05) with egg wet weight and with both the absolute level and the percentage of protein phosphorus in the egg. There was significant positive correlation (P<0.05) between the percentage of hatched eggs (alevins) surviving to first feeding and each of the following: egg wet weight, egg dry weight and absolute levels in the egg of bound lipid, precipitable protein and protein phosphorus. Egg batches with higher hatching percentage (>50%) differed significantly from those with zero hatching percentage in having (in absolute terms) higher egg weight, chorion weight, protein phosphorus (all P<0.001), egg dry weight, bound lipid and precipitable protein (all P<0.01) and (percentages) higher chorion weight (P<0.05) and protein phosphorus (P<0.001), and lower free and total lipid (both P<0.01) and iron (P<0.05). In a separate experiment to investigate the effects of allowing the eggs to be retained by the female within the abdominal cavity for increasing periods of time after ovulation, eggs were obtained from three females on three or four successive occasions 2–11 days apart. Although the above aspects of egg composition remained almost constant when the eggs were held in the female for up to 18 days after ovulation, the hatching percentage declined sharply within this period, in two females falling from over 90% to near zero. These results together indicate that the time of stripping of the eggs in relation to the date of ovulation is a much more significant determinant of egg quality than any of the chemical and physical aspects of egg composition which were investigated. 相似文献
20.
The changes in egg lipids and fatty acid compositions that occur during embryonic development of spotted wolf‐fish, Anarhichas minor, were examined by monitoring individual egg batches from the time of spawning (egg stripping) until hatching. The lipids, present as 3.7±0.1% of the wet mass of the freshly stripped eggs, contained high percentages of monoenes (monounsaturated fatty acids (MUFAs), ca. 33%) and polyenes (ca. 43%) and approximately 20% saturated fatty acids (SFAs). The fatty acid profiles were dominated by a small number of fatty acids. The major SFA was 16:0 (ca. 14%), the dominant MUFA was 18:1 n‐9 (ca. 21%), and among the polyenes, the n‐3 highly unsaturated fatty acids (HUFAs) 22:6 n‐3 docosahexaenoic acid (DHA) and 20:5 n‐3 eicosapentaenoic acid (EPA) were present in the highest concentrations (EPA, ca. 16%; DHA, ca. 19%). The n‐6 HUFA 20:4 n‐6 arachidonic acid (AA) was present as ca. 1% of the total fatty acids in the freshly stripped eggs. This resulted in an AA:EPA of ca. 0.07, which is lower than reported for eggs of many other fish species. As embryonic development progressed, the percentage contribution of AA to the total fatty acids almost doubled. There were also increases in the relative proportions of SFAs (due mainly to an increase in the percentage of 16:0 to ca. 16% at hatch) and DHA (to ca. 23%), and there was a corresponding decrease in the percentage of MUFAs (mostly brought about by a decrease in the percentage of 18:1 n‐9 to ca. 18% at hatch). The most marked changes occurred towards the end of incubation. The percentage of EPA changed little during incubation. This implies that there was selective retention of DHA, 16:0 and AA, and these fatty acids were probably incorporated into cell membranes. MUFAs, particularly 18:1 n‐9, seem to have been catabolized to provide energy for the developing embryo, and some EPA also seems to have been utilized as an energy source. Survival of eggs to the eyed stage (range ca. 10–80%) and to hatch (ca. 5–75%) was negatively correlated with the %AA, %EPA and AA:DHA of the freshly stripped eggs. There was also a negative correlation between AA:EPA and egg survival, which implies that there is not a universal requirement for a high AA:EPA to ensure high rates of survival of fish eggs. 相似文献