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1.
A study was conducted to evaluate the effects of dietary carbohydrates on triglyceride, cholesterol and fatty acid concentrations in abalone, Haliotis discus hannai Ino. Six semi-purified diets with different carbohydrates (dextrin, heat-treated wheat starch, wheat starch, corn starch, tapioca starch and potato starch, respectively), all containing a carbohydrate level of 33.5%, were fed to abalone (initial shell length: 29.98 mm±0.09 mm; initial weight. 3.42 g±0.02 g) for 24 weeks in a recirculation system. The results indicate that serum triglyceride concentrations were significantly (P<0.05) higher in the abalone fed with dextrin, heat-treated wheat starch and wheat starch than those fed with corn starch, and serum cholesterol concentrations were significantly (P<0.05)higher in the abalone fed with dextrin, heat-treated wheat starch than those fed with corn starch. Fatty acid C20:4n-6 in the foot muscles were significantly (P<0.05) lower in the abalone fed with dextrin than those fed with wheat starch, corn starch, tapioca starch and potato starch. Fatty acid C20:4n-6 in hepatopancreas was significantly (P<0.05) lower in abalone fed with heat-treated wheat starch than those fed with corn starch, tapioca starch and potato starch. Fatty acid C22:6n-3 in the foot muscles were significantly (P< 0.05) lower in the abalone fed with dextrin and heat-treated wheat starch than those fed with wheat starch and potato starch.  相似文献   

2.
以鱼粉、酪蛋白和明胶为蛋白源,分别以20%添加水平的葡萄糖、糊精、蔗糖、玉米淀粉、小麦淀粉和马铃薯淀粉为糖源,配制成6种不同糖源的等氮等能饲料,研究不同糖源对方斑东风螺幼螺生长性能、饲料利用、消化酶活性、糖原含量、蛋白质含量及肉壳比的影响。结果表明:方斑东风螺幼螺的增重率、特定生长率、饲料系数、蛋白质效率,消化酶活性、糖原含量、蛋白质含量及肉壳比均受到糖源种类的显著影响(P<0.05)。增重率、特定生长率从高至低依次为小麦淀粉组、玉米淀粉组、马铃薯淀粉组、糊精组、葡萄糖组、蔗糖组;饲料系数及蛋白质效率均以小麦淀粉组表现最好,与马铃薯淀粉组和玉米淀粉组无显著性差异,显著优于糊精组、葡萄糖组及蔗糖组。消化酶活性的分析结果表明,淀粉酶活性最高的是蔗糖组和小麦淀粉组,糊精组次之,葡萄糖组和马铃薯淀粉组的淀粉酶活性最低;各处理组脂肪酶活性存在显著差异,从高至低分依次为马铃薯淀粉组>小麦淀粉组>糊精组>玉米淀粉组>蔗糖组、葡萄糖组;蛋白酶活性以小麦淀粉组最高,其次为蔗糖组,其他糖源组并无显著差异;而内脏团糖原和肌糖原含量,除了葡萄糖组外,其他各组差异不显著(P>0.05);蛋白质含量以葡萄糖组最高,小麦淀粉组最低,而肉壳比则刚好相反,以小麦淀粉组和玉米淀粉组最高,葡萄糖组最低。以生长、饲料利用率和消化酶活性为评价指标,方斑东风螺饲料中采用小麦淀粉作为糖源效果最优。  相似文献   

3.
A feeding trial was conducted in a recirculating water system to investigate the effects of dietary protein levels on growth, feed utilization, hepatosomatic index and liver lipid deposition of juvenile red snapper, Lutjanus argentimaculatus (average initial wet weight 8.0 ± 0.39 g and total length 3.14 ± 0.3 cm). In the experiment, six fishmeal-based diets were formulated to contain various protein levels (20% to 45% in 5% increments), with dietary energy ranging from 2210.7kJ lOOg to 2250.2kJlOOg dry matter. The protein to energy ratios of diets ranged from 8.58 mg protein kJ−1 to 20.03 mg protein kJ−1. Diets were fed for 90d to triplicate groups of fish stocked in 0.128m3 seawater tanks, 25 individuals each. The daily ration of 2% wet body weight was offered to the fish thrice a day. The fish at the end of the study had more than ten-fold (77.0g) increase in weight compared to the initial (8.0g). Fish fed diets of 40% and 45% protein produced significantly (P<0.05) higher weight gain of 77.2g and 76.5g, and specific growth rate (SGR) of 2.65% and 2.62% than those of 67.0 g and 68.3g, and 2.49% and 2.51% of the other diets. The broken-line regression of SGR against dietary protein level yielded an optimum dietary protein requirement of 42.6% (Y=−1.6295 + 0.1114 X 2,P<0.05). Survival remained 100% among groups. Feed conversion ratio decreased from 0.45 for fish fed 20% dietary protein to 0.35 for fish fed 45% dietary protein. Nitrogen intake increased with an increase in dietary protein, which in turn resulted in an increase in nitrogen gain of fish whole body. Fish fed 40% and 45% protein diets showed higher (P<0.05) nitrogen gain (0.27g and 0.26g) than those (0.23g and 025g) fed all other diets. Gross energy intake (GEI) in fish fed 45% protein was lower (600.67kJ) than that (607.97 kJ) of 40% protein diet, though the differences were not statistically significant (P>0.05); GEI ranging from 677.31 kJ to 663.20 kJ at remaining four diets (20% to 35% protein) did not appear to differ significantly (P>0.05). The highest energy gain of 518.33 kJ was obtained with fish fed 40% protein, resulting in the highest energy retention efficiency of 85.26%. The hepatosomatic index of fish fed diets of 20%, 25%, 30% and 35% protein were significantly (P<0.05) higher (2.09% to 2.57%) than those (1.44% and 1.41%) of fish fed diets containing 40% and 45% protein. Liver lipid contents decreased from 8.72% to 7.0% in fish fed dietary protein of 20% to 45% in 5% increments. Results suggest that the diet containing 40% to 42.6% protein with a P/E ratio of 17.6 mg protein kJ−1 is required for good growth of L. argentimaculatus weighing between 8.0 g and 85.2 g under the culture conditions of the present study.  相似文献   

4.
A 120-day feeding experiment was conducted to investigate the effects of partial replacement of brown fish meal (BFM) by fermented soybean meal (FSBM) in diets of Chinese soft-shelled turtle (Pelodiscus sinensis). The turtles (initial mean body weight, (115.52 ± 1.05) g) were fed with three experimental diets, in which 0%, 4.72% and 9.44% BFM protein was replaced by 0%, 3% and 6% FSBM, respectively. Results showed that the feeding rate (FR), specific growth rate (SGR) and feed efficiency ratio (FER) of turtles fed with the diet containing 3% FSBM were not significantly different from the control group (0% FSBM) (P > 0.05). However, FR, SGR and FER of turtles fed with the diet containing 6% FSBM were significantly lower than those of the control group (P < 0.05). No significant differences were observed in the activities of serum glutamic-oxalacetic transaminase and glutamicpyruvic transaminase among dietary treatments (P > 0.05). However, the uric acid concentration in turtles fed with the diet containing 3% or 6% FSBM was significantly lower than that in the control group (P < 0.05). There were no significant differences in the activities of lysozyme, alkaline phosphatase and total superoxide dismutase among dietary treatments (P > 0.05). The results suggested that FSBM could replace 4.72% BFM protein in turtle diets without exerting adverse effects on turtle growth, feed utilization and measured immune parameters.  相似文献   

5.
The effect of dietary phosphorus on the growth and body components of juvenile Synechogobius hasta was determined. Different percentages of dietary phosphorus (0.63, 0.77, 0.93, 1.06, 1.22 and 1.36) were tested by feeding the fish (body weight, 15.81 g ± 0.32 g; 20 individuals each group; 3 groups each percentage) at a surplus of 5%–10% above satiation for 35 d. Dietary phosphorus did not significantly affect the specific growth rate, feed intake, feed conversion ratio and protein efficiency rate. Nitrogen retention was found to be the highest in fish fed the diet containing 1.06% of phosphorus; however, this was not significantly different from other diets. Fish fed the diet containing 0.93% of phosphorus showed the highest phosphorus retention; similar phosphorus retention rates were found in fish fed the diets containing 0.77% and 1.06% of phosphorus. Fish fed the diet containing the highest percentage of dietary phosphorus were found to contain the least whole body lipid, lower than fish fed other diets (P<0.05). The protein content increased from 18.59% to 19.55% (although not significant) with the decrease of body lipid content (P>0.05). The contents of the whole body ash, whole body phosphorus and vertebrae phosphorus increased with dietary phosphorus percentage up to 1.06 (P<0.05), reaching a plateau after that. Dietary phosphorus did not significantly influence the muscle components (protein, lipid and moisture). Condition factor and hepatosomatic index were the highest in fish fed the diet containing 0.63% of dietary phosphorus; however, this was not significantly different from those of other diets. The second-order polynomial regression of phosphorus retention against dietary phosphorus identified a breakpoint at 0.88% of dietary phosphorus. However, the dietary requirement of phosphorus for maintaining maximum phosphorus storage determined by broken-line analysis of the contents of whole body phosphorus, and ash and vertebrae phosphorus was 1.06% of the diet.  相似文献   

6.
A growth experiment was conducted on cobia(Rachycentron canadum,initial weight 108.2 g ± 3.0 g) to investigate the effects of dietary corn gluten meal(CGM) levels on the fish growth,whole body composition and protein metabolism in relation to specific gene expression.Five isonitrogenous(crude protein 45%) and isoenergetic(gross energy 20 kJ g 1) practical diets were formulated by replacing 0%(the control),17.5%,35.0%,52.5%,and 70.0% of fish meal(FM) protein with CGM protein.No significant differences were observed in the survival,feed intake(FI),specific growth rate(SGR),feed efficiency(FE) and protein productive value(PPV) among fish fed diets with 0%,17.5%,35.0%,and 52.5% of CGM protein.However,these indices were significantly lower in fish fed the diet with 70.0% of CGM protein than those in fish fed the control diet(P < 0.05).The whole-body crude protein and lipid contents were significantly lower while the whole-body moisture content was significantly higher in fish fed the diet with 70.0% of CGM protein compared with the control group(P < 0.05).When 70.0% of FM protein was replaced by CGM,plasma total protein and cholesterol contents were significantly lower than those in the control group(P < 0.05).Fish fed the diet with 70.0% of CGM protein had significantly lower hepatic insulin-like growth factor I(IGF-I) expression levels than those in the control group(P < 0.05).However,no significant differences were observed in hepatic target of rapamycin(TOR),dorsal muscle IGF-I and TOR expression levels among dietary treatments.Results of the present study indicated that 52.5% of FM protein could be replaced by CGM in the diets without significant influences on the growth,feed utilization and protein metabolism of juvenile cobia.The present results might be useful for developing cost effective and sustainable cobia dietary formulations.  相似文献   

7.
We conducted a preliminarily study on the effects of dietary guaiacol on growth performance of abalone, Haliotis discus hannai Ino. Seven semi-purified diets were formulated with graded levels of guaiacol (0, 5, 10, 50, 100, 500, and 1 000 mg kg−1). Abalone (initial weight: 0.29 ± 0.01 g; initial shell length: 8.55 ± 0.27 mm) were fed with these diets in a re-circulated water system for 152 days. Guaiacol significantly improved the specific growth rate (SGR) (P<0.05); excessive dietary guaiacol (1 000 mg kg−1) led to significantly high mortality (P<0.05), and lipid content in the soft body increased significantly after dietary guaiacol (P<0.05). Activities of catalase and phenoloxidase (PO) in the viscera were significantly stimulated by dietary guaiacol (P<0.05). Broken-line analysis based on SGR indicated that the minimum dietary guaiacol for the optimal growth of juvenile abalone is 15.43 mg kg−1.  相似文献   

8.
The availability of phosphorus to juvenile abalone,Haliotis discus hannai from primary, secondary and tertiary calcium phosphate, primary sodium or potassium phosphate separately or in combination was determined in a 120-day feeding trial. Seven semi-purified diets were formulated to contain relatively constant dietary phosphorus, ranging from 0.78%–0.82%. The concentrations of dietary phosphorus were presumed to be slightly below the requirement for abalone. A brown alga,Laminaria japonica, was used as a control diet. Abalone juveniles of silimar size (average weight 1.18 g; average shell length 18.74 mm) were distributed in a single-pass, flow-through system using a completely randomized design with eight treatments and three replicates each treatment. The survival ranged from 71.1% to 81.1%, and was not significantly (P>0.05) related to dietary treatment. However, the weight gain rate (41.72%–65.02%), daily increment in shell length (36.87–55.07 μm) and muscle RNA-DNA ratio (3.44–4.69) were significantly (P<0.05) affected by dietary treatment. Soft body alkaline phosphatase activity (10.9–19.8 U/g wet tissue) and carcass levels of lipid (7.71%–9.33%) and protein (46.68%–49.35%) were significantly (P<0.05) responsive to available phosphorus of the diets. Dietary treatment had significant effect (P<0.05) on concentrations of phosphorus in the whole body (WB) and soft body (SB). Apparent digestibility coefficients (45%–97%) of phosphorus were also significantly (P<0.05) different between dietary treatments. The results indicated that among these inorganic compounds, primary calcium, potassium and sodium phosphates separately or in combination could be utilized effectively by juvenile abalone as dietary phosphorus sources (availability ranging from 87%–97%). However, secondary and tertiary calcium phosphates were found to be low in availability, the values being 45% and 77%, repectively. Project 39670572 supported by the Natural Science Foundation of China (NSFC).  相似文献   

9.
This experiment was conducted to examine the effects of salinity fluctuation frequency on the growth, molting rate and hemolymph 20-hydroxyecdysone (20-HE) concentration for juvenile Fenneropenaeus chinensis with an initial wet body weight of 1.115 g±0.012 g. The salinity of the control treatment (represented by D0) was 28 throughout the experiment, whereas treatments D2, D4, D6 and D8 were subjected to different salinity fluctuation frequencies of 2, 4, 6 and 8 d, respectively. The range of salinity fluctuation was 4. The salinity in treatments D2, D4, D6 and D8 was kept at 28 for 2, 4, 6 and 8 d, respectively; each original salinity was decreased abruptly to salinity 24, which first lasted for another 2 d and was then raised to its initial value 28. This constituted a salinity fluctuation cycle and afterwards the cycle repeated. It was found that: 1) The weight gain of shrimp in treatment D4 was 202.9% and significantly higher than that in treatment D0 (P<0.05). The molting rate in treatment D2 was the lowest, while that in treatment D6 was the highest and significantly higher than those in treatments D0 and D2 (P<0.05). 2) The hemolymph 20-HE concentration of shrimps in all treatments was at low levels and increased first gradually during the inter-molt period and then increased sharply. It reached a peak value during the pre-molt stage, and then decreased abruptly during the post-molt stage when the lowest level occurred. 3) During the post-molt stage, the hemolymph 20-HE concentration in treatment D2 was 7.47 pg μL−1 and significantly higher than that in treatment D0 (P<0.05). There were, however, no significant differences in hemolymph 20-HE concentration among all five treatments during the inter-molt stage (P>0.05). During the pre-molt stage, the hemolymph 20-HE concentration in treatment D6 was significantly higher than that in treatment D0 (P<0.05), whereas the hemolymph 20-HE concentration in treatment D2 was significantly lower than that in other treatments (P<0.05). Adequate salinity fluctuation promoted the molting rate through increasing hemolymph 20-HE concentration at the pre-molt stage.  相似文献   

10.
In order to reveal transpiration rates of wetland plants and its relationships to micro- meterological factors in a mountain valley wetland, relative humidity, air temperature, leaf temperature, soil temperature, photo flux density and transpiration rates were measured once two hours in a Carex meyeriana wetland of the Changbai Mountain valley in dry （July） and wet （September） of 2003, respectively. Results showed that the tendency of ＂decreasing after increasing＂ was obvious in wet season. However, a relatively stable trend was observed for the transpiration in dry season.. Generally, the photon flux density of Carex meyeriana was higher in wet season than that in dry season. However, the variabilities of leaf temperature, air temperature and relative humidity were similar in both seasons. Higher transpiration rates of Carex meyeriana leaves were observed in July （varied from 40 to 150 mol.m^-2.s^-1） compared to those （varied from 7 to 14 mol.m^-2.s^-1） in September. Transpiration rates were significantly correlated with air temperature （P〈0.01）, leaf temperature （P〈0.01）, and wind speed （P〈0.05）, but correlationship between relative humidity and photo flux density was not significant （P〈0.05）.  相似文献   

11.
Lipid oxidation in salt-dried yellow croaker (Pseudosciaena polyactis) was evaluated during processing with commonly used analytical indices, such as the peroxide value (POV), the thiobarbituric acid reactive substances (TBARS) value, and oxidative-relative lipoxygenase (LOX) activity. Additionally, fatty acids were analyzed using gas chromatography-mass spectrometry. Both POV and TBARS increased significantly (P < 0.05) at the rinsing stage. POV reached its peak value of 3.63 meq O2 per kg sample at the drying stage, whereas TBARS constantly increased from 0.05 to 0.20 mg MDA per kg sample. Processing of salt-dried yellow croaker had an extremely significant (P < 0.01) effect on LOX activity. Twenty-six fatty acids were identified. Combined eicosapentaenoic acid (EPA; C20:5n3) and docosahexaenoic acid (DHA; C22:6n3) content varied between (19.20 ± 0.37) mg g?1 and (23.45 ± 1.05) mg g?1. The polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) ratio in yellow croaker was 0.73–1.10, and the n-6/n-3 PUFA ratio was approximately 0.13–0.20. The contents of most fatty acids varied significantly (P < 0.05) during the different processing stages, and these differences were caused by lipid oxidation. C18:0, C16:1n7, C19:0, and C22:6n3 showed clear changes in principle component one of a principle components analysis. These fatty acids are potential markers for evaluating lipid oxidation in fish muscle because there was a significant correlation between these markers and TBARS and LOX activity (P < 0.05) with Pearson’s coefficients > 0.931.  相似文献   

12.
The bioavailability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) depends on their chemical forms. This study investigated the long-term effects of DHA-bound triglyceride (TG-DHA), DHA-bound phospholipid (PL-DHA), and the combination of TG-DHA and egg yolk phospholipid (Egg-PL) on lipid metabolism in mice fed with a high-fat diet (fat levels of 22.5%). Male C57BL/6J mice were fed with different formulations containing 0.5% DHA, including TG-DHA, PL-DHA, and the combination of TG-DHA and Egg-PL, for 6 weeks. Serum, hepatic, and cerebral lipid concentrations and the fatty acid compositions of the liver and brain were determined. The concentrations of serum total triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), and hepatic TG in the PL-DHA group and the combination group were significantly lower than those in the high-fat (HF) group (P < 0.05). Atherogenic index (AI) of the PL-DHA group was significantly lower than that of the combination group (P < 0.05). Hepatic TC level in the combination group was significantly lower than that in the HF group (P < 0.05), but no significant difference was observed between the combination group and the PL-DHA group. Both the PL-DHA and the combination groups showed significantly increased DHA levels in the liver compared with the HF group (P < 0.05). However, there were no obvious increases in the cerebral DHA levels in all DHA diet groups. These results suggest that PL-DHA was superior to the combination of TG-DHA and Egg-PL in decreasing the AI. Long-term dietary supplementation with low amount of DHA (0.5%) may improve hepatic DHA levels, although cerebral DHA levels may not be enhanced.  相似文献   

13.
Prepared in this experiment were six groups of diets, i.e. VC0, VC1, VC2, VC3, VC4 and VC5 with the contents of vitamin C (VCmg(100 g)−1 diet) of 0, 100, 200, 400, 800, and 1200 respectively. It was found that vitamin C increased the concentrations of immunoglobulin-like (IgG-like, IgA-like and IgM-like) substances in the serum of Penaeus chinensis after a feeding period of 3 weeks. The differences among groups were significant (P<0.01), but there was no difference in the contents of complement3-like and complement4-like substances in the serum (P>0.05). Phenoloxidase (PO) activity in the serum of VC3 group shrimps was higher than that of VC0 and other groups, but no significant difference was observed between VC0 group and other groups. Furthermore, bactericidal activity of the serum to Vibrio parahaemolyticus in shrimps fed with the VC1 diet was higher than that in the other groups (P<0.01), while no difference was demonstrated among all groups for the bactericidal activity to Vibrio alginolyticus (P>0.05). It is, therefore, suggested that vitamin C (100–400 mg(100 g)−1 diets) could be used as an immunostimulant of P. chinensis.  相似文献   

14.
The toxic effects of benzo[α]pyrene (B[α]P) at different concentrations (0.1, 0.5, 1, 2.5 and 7.5 μgL−1) on scallop (Chlamy farreri) immune system were studied. The results showed that B[α]P had significant toxic effects on the haemocyte counts, neutral red uptake, phagocytosis, bacteriolytic and antibacterial activity (P<0.05), while the seawater control and acetone control had no significant differences. The haemocyte counts, neutral red uptake, phagocytosis and bacteriolytic activity in all B[α]P treatment groups as well as antibacterial activity in groups of 0.5, 1, 2.5 and 7.5 μgL−1 B[α]P decreased significantly (P<0.05). Some of these indices tended to be stable on the sixth day and others on the ninth day, and the indices showed clear time- and concentration-response to B[α]P. Bacteriolytic activity in 0.1μgL−1 B[α]P treatment group and antibacterial activity in 0.1 μgL−1 and 0.5 μgL- B[α]P treatment groups increased at the beginning of exposure and reached their peaks on day 1 and day 6, respectively. Following that, both activities decreased gradually and became stable after day 9. When all the indices reached stability, they were significantly lower than those in control group (P<0.05), except for antibacterial activity in 0.1 μgL−1 B[α]P treatment group (P>0.05). Thus, B[α] has evident toxic effects on scallop immune system, which supports the view that a relationship exists between pollution and immunomodulation in aquatic organisms.  相似文献   

15.
An experiment was performed to determine the dietary phosphorus requirement of the young abalone,Haliotis discus hannai. Five semi-purified diets were formulated to provide a series of graded levels of dietary total phosphorus (0.23%–1.98) from monobasic potassium phosphate (KH2P04). The brown alga,Laminaria japonica, was used as a control diet. Similar size abalone were distributed in a single-pass, flow-through system using a completely randomized design with six treatments and three replicates each treatment. The abalone were hand-fed to satiation with appropriate diets in excess, once daily at 17:00. The feeding trial was run for 120-d. Survival rate and soft-body to shell ratio (SB/S) were constantly maintained regardless of dietary treatment. However, the weight gain rate (WGR), daily increment in shell length (DISL), muscle RNA to DNA ratio (RNA/DNA), carcass levels of lipid and protein, soft-body alkaline phosphatase (SBAKP), and phosphorus concentrations of whole body (WB) and soft body (SB) were significantly (ANOVA, P<0.05) affected by the dietary phosphorus level. The dietary phosphorus requirements of the abalone were evaluated from the WGR, DISL, and RNA/DNA ratio respectively, by using second-order polynomial regression analysis. Based on these criteria, about 1.0%–1.2% total dietary phosphorus, i.e. 0.9%–1.1% dietary available phosphorus is recommended for the maximum growth of the abalone. Project 39670572 supported by the NSFC.  相似文献   

16.
A feeding trial was carried out to investigate the dietary vitamin E requirement of the oriental river prawn Macrobrachium nipponense (weight of 0.3–0.4 g) and its effect role on antioxidant activity. Prawns were fed with seven levels of vitamin E (0, 25, 50, 75, 100, 200, and 400 mg/kg diet) for 60 days. The results show that dietary vitamin E supplementation could significantly increased the prawn weight (P < 0.05). The activity of superoxide dismutase (SOD) in the hepatopancreas was significantly higher in prawns fed with diets supplemented with ≤75 mg/kg vitamin E than in those fed with diets supplemented with 100–400 mg/kg vitamin E (P < 0.05). The activity of catalase (CAT) in the hepatopancreas decreased significantly as dietary vitamin E supplementation increased (P < 0.05), and no significant difference was detected in glutathione peroxidase (GSH-Px) activity between different dietary groups (P >0.05). The contents of vitamin E in the hepatopancreas and in the muscle increased with increasing dietary vitamin E. There was a linear correlation between the vitamin E level in diet and that in muscle, and between the vitamin E level in diet and that in the hepatopancreas. All the above results indicated that dietary vitamin E can be stored in the hepatopancreas and muscle and lower both the activities of SOD and CAT in the hepatopancreas, suggesting that it is a potential antioxidant in M. nipponense. Broken line analysis conducted on the weight gains of prawns in each diet group showed that the dietary vitamin E requirement for maximum growth is 94.10 mg/kg.  相似文献   

17.
We conducted a complete diallel cross among three geographically isolated populations of Pacific abalone Haliotis discus hannai Ino to determine the heterosis and the combining ability of growth traits at the spat stage. The three populations were collected from Qingdao (Q) and Dalian (D) in China, and Miyagi (M) in Japan. We measured the shell length, shell width, and total weight. The magnitude of the general combining ability (GCA) variance was more pronounced than the specific combining ability (SCA) variance, which is evidenced by both the ratio of the genetic component in total variation and the GCA/SCA values. The component variances of GCA and SCA were significant for all three traits (P<0.05), indicating the importance of additive and non-additive genetic effects in determining the expression of these traits. The reciprocal maternal effects (RE) were also significant for these traits (P<0.05). Our results suggest that population D was the best general combiner in breeding programs to improve growth traits. The DM cross had the highest heterosis values for all three traits.  相似文献   

18.
Optimal stocking densities were investigated for the sea cucumber Apostichopus japonicus Selenka under feed-supplement and non-feed-supplement regimes in net enclosures for 333 d. Substantial weight loss occurred during the aestivation phase (AE). Decreased growth rates were also observed during the winter phase (WT). In contrast, sea cucumbers showed rapid growth during the spring (SP) and autumn (AU) phases. Feeding regimes considerably influenced the growth performance, i.e., sea cucumbers grew faster under feed-supplement regime than under non-feed-supplement regime (P < 0.05). The average survival rates of sea cucumbers under feed-supplement regime were higher than those under non-feed-supplement regime for both the autumn phase and spring phase, but the differences were only significant for the latter phase (P < 0.05). The fitted B-N curves showed that the optimal stocking densities, in terms of net production, were 22.3 ind. m-2 for feed-supplement regime and 14.1 ind. m-2 for non-feed-supplement regime.  相似文献   

19.
Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that copepods can meet the nutritional requirements of fish larvae. In this study, calanoid copepod Schmackeria poplesia, rotifer Brachionus plicatilis and anostraca crustacean Artemia sp. were analyzed for fatty acid contents, and were used as live food for culturing larval Japanese flounder, Paralichthys olivaceus. The total content of three types of HUFAs (DHA, EPA and ARA) in S. poplesia was significantly higher than that in the other two live foods (P<0.01). Three live organisms were used for raising larvae and juveniles of Paralichthys olivaceus respectively for 15 and 10 d. Then the growth, survival and fatty acid composition of the larvae and juveniles were investigated. The results showed that the larvae and juveniles fed with copepods (S. poplesia) had significantly higher growth rate than those fed with the other two organisms (P<0.01). The survival of the flounder larvae fed with copepods was significantly higher than that of the others (P<0.01), and the survival of the juvenile fish fed with copepods was higher than that fed with Artemia (P<0.05). The contents of three types of HUFAs (DHA, EPA and ARA) and the ratio of DHA/EPA in larval and juvenile flounder P. olivaceus were analyzed. The results showed that the contents of DHA, EPA and ARA in the larvae and juveniles fed with S. poplesia were higher than those fed with a mixed diet or Artemia only, and the ratio of EPA/ARA in larvae and juveniles of P. olivaceus fed with S. poplesia was lower than that in the case of feeding with a mixed diet or Artemia only. The present data showed that copepod is the best choice for feeding the larvae and juveniles of fish considering its effects on the survival, growth and nutrition composition of the fish.  相似文献   

20.
A 13-day feeding trial was carried out to evaluate the effectiveness of a microbound diet for rearing the larvae of Chinese shrimp Fenneropenaeus chinensis in comparison with the live foods that consist of Isochrysis galbana, Chlorella vulgaris, Tetraselmis chuii, rotifer (Brachionus plicatilis) and Artemia sp. Larvae of 0 to 13d post-hatch (dph) were reared in a temperature-controlled semi-open culture system and stocked at a density of 100 larvae L−1 in tanks, each containing 50 L sterilized seawater with salinity 30–32. Larvae were manually fed either the live foods or the microbound diet 6 times per day. At 13dph, the growth of the larvae fed on the microbound diet was approximately 84% of that fed on the live foods. The survival rate of the larvae fed on the microbound diet was 44.29% at 13 dph, which was not significantly different from that of larvae fed on live foods (63.55% ). The body length and development index (DI) of the larvae fed on the microbound diet were always lower than those of larvae fed on live foods. However, the differences reached significant levels only at 11 and 13dph (P<0.05). The mean dry weight loss of the microbound diet was 9.2% after 90min immersion in seawater, indicating that this diet has a good water stability. The microbound diet contains 5223% crude protein and 10.27% lipid and is easy to prepare. These characteristics of the diet suggest good potentials for its successful use in the larviculture of other penaeid and fish species.  相似文献   

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