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1.
Phototrophic Bacteria as Feed Supplement for Rearing Penaeus monodon Larvae   总被引:1,自引:0,他引:1  
Larvae of the giant tiger prawn Penaeus monodon were reared from the naupliar to pos-tlarval stage, based on a diet of waste-grown phototrophic bacterium Rhodovulum sulfido-philum , the marine diatom Skeletonema costatum , and brine shrimp Artemia The experimental design consisted of feeding the protozoea with diatoms and varying proportions of bacterial biomass as diet D0 (0%), D1 (1%), D2 (2%), D3 (3%), and D5 (5%), while mysis and postlarvae were fed the above diet supplemented with Artemia nauplii. Controls were not fed with bacteria biomass (diet D0). The addition of R. sulfidophilum biomass in the diet had significant effects on the growth and survival of P. monodon larvae. In the first experiment, the larvae fed with diet D1 ( Skeletonema + 1% R. sulfidophilum ) reached the first postlarval stage (PL1) on the ninth day of feeding and had a mean total length (TL) of 6.13 ± 0.05 mm, which was significantly higher ( P < 0.001) than TL of larvae fed with the other three diets. In another experiment, prawn larvae fed with diet D2 had the highest overall survival of 46% and a significantly larger mean TL of 6.88 ± 0.18 mm at PL1 compared to larvae fed with diet D0 and D3 ( P > 0.05). However, in both experiments prawn larvae fed with the various diets showed significant differences in their length-at-stage ( P > 0.05), and the lowest growth and survival were obtained from diets comprising 3% and 5% bacterial biomass, which also gave the highest levels of ammonia-nitrogen in the culture water. Addition of more than 2% R. sulfidophilum biomass apparently deteriorates the quality of the culture water.  相似文献   

2.
Nutritional efficacy of fairy shrimp (Streptocephalus sirindhornae) nauplii, as a live food, was studied for growth performance and survival rate of giant freshwater prawn (Macrobrachium rosenbergii) postlarvae. A feeding experiment was designed with four different feeds: dry commercial feed, fairy shrimp nauplii, Artemia sp. nauplii and adult Moina macrocopa. Results from the nutritional composition revealed that fairy shrimp nauplii had protein and lipid contents of 54.58 ± 2.8 g kg?1 and 255 ± 2.8 g kg?1, respectively. The highest value for an individual amino acid in fairy shrimp was lysine (140.7 ± 1.6 g kg?1). The essential amino acids content in the whole body of the larval prawns was in the range of 66.7–67.5 g kg?1. Fairy shrimp nauplii had the highest essential amino acid ratio (A/E) of lysine, similarly, in musculature of prawn larvae. Weight gain and specific growth rate of the postlarvae fed with fairy shrimp nauplii were significantly higher than those fed with Artemia nauplii, adult Moina and dry commercial feed. The presented results suggest that S. sirindhornae nauplii can be used as a nutritionally adequate food for freshwater prawn M. rosenbergii postlarvae.  相似文献   

3.
This study investigated the effect of dietary astaxanthin supplementation on egg quality and juvenile growth of long snout seahorse (Hippocampus guttulatus). Captive breed seahorse broodstock were fed four diets composed of frozen shrimp [Atlantic ditch shrimp, Palaemonetes varians) used as a vector to deliver artificial diets with increasing levels of astaxanthin (0, 75, 100 and 125 mg kg?1 dry weight)]. The results indicated that the astaxanthin uptake into eggs from the enriched shrimp diets was highly efficient. Females fed unsupplemented astaxanthin diet produced similar‐sized eggs with lower concentration of astaxanthin than females fed diets with astaxanthin. The lower concentration of astaxanthin in the eggs was correlated with the production of smaller juveniles in comparison with the juveniles hatched from parents fed supplemented astaxanthin diets. Juvenile growth and survival was limited by their size on release from the male's pouch as at the end of 28‐day postparturition juveniles produced with the diet with no astaxanthin were still significantly smaller (P < 0.05) than those produced from parents fed astaxanthin‐supplemented diets. These results demonstrate a significant benefit of dietary astaxanthin supplementation in long snout seahorse diets in terms of improved egg quality and juvenile growth and survival.  相似文献   

4.
日本对虾仔虾培育试验   总被引:2,自引:1,他引:2  
用无节幼体培育仔虾,采用的对虾幼体饵料有中肋骨条藻、卤虫无节幼体及台湾产的人工配合饵料,并注意饵料的配合使用及消毒工作;为维持水质稳定,整个培育期间不换水,加大布气石的密度(3.6个/m2)。在300m3水体中,一茬育出仔虾2218万尾,成活率为66.2%,取得了良好的经济效益。  相似文献   

5.
A feeding experiment was carried out to determine the efficiency of different commercial sources, chemical forms and levels, of dietary astaxanthin, to appropriately pigment the red porgy (Pagrus pagrus) skin. According to this, total carotenoid content, profiles and chemical forms present in the skin were determined. In order to establish the potential for antioxidant protecting role of astaxanthin supplemented diets, peroxide levels and lipid composition of skin were also determined.

Red porgy alevins were fed six dietary treatments in triplicate; a basal diet (B) without carotenoids; two diets (N25 and N50) formulated to supply either 25 or 50 mg kg− 1 of an esterified source of astaxanthin (Haematococcus pluvialis, NatuRose™); two diets (CP25 and CP50) with either 25 or 50 mg kg− 1 of unesterified astaxanthin (Carophyll® Pink); and a positive control diet (B + S) proved as a successful pigmenting-diet in previous experiences (B + S, 88% basal diet:12% frozen shrimp) [Cejas, J., Almansa, E., Tejera, N., Jerez, S., Bolaños, A., Lorenzo, A., 2003. Effect of dietary supplementation with shrimp on skin pigmentation and lipid composition of red porgy (P. pagrus) alevins. Aquaculture 218, 457–469].

All fish fed carotenoid supplemented diets displayed a pink-coloured skin after 4 months of feeding in contrast to the greyish appearance displayed by fish fed the basal diet not supplemented with carotenoids (B). Furthermore, astaxanthin diesters were the major carotenoid in the skin of pink fish. A second carotenoid, tentatively identified as tunaxanthin diester, was also detected. The best results in terms of skin natural reddish hue, total carotenoid and astaxanthin contents were found by using the esterified forms of dietary astaxanthin (N25, N50 and B + S). Interestingly, the lowest levels of lipid peroxides were found in the fish fed these three treatments. However, no effect of treatment on lipid composition was found. In conclusion, red porgy alevins are able to efficiently utilise dietary natural or synthetic astaxanthin, and deposit this pigment in its esterified form to acquire an acceptable pink-coloured skin compared to that of the wild fish.  相似文献   


6.
参虾池塘高效混养技术   总被引:1,自引:0,他引:1  
7-9月刺参夏眠期间正是日本对虾快速生长的季节,在对虾池中人工造礁,第1年4月放入规格为80~120头/ kg的海参苗1740 kg,每年7月放入体长0.7~1.0 cm的日本对虾虾苗1.2×105尾,将刺参与日本对虾混养.在养殖过程中,刺参不投喂,只用卤虫、人工饲料、杂色蛤和四角蛤蜊投喂日本对虾,严格控制养殖池内的杂鱼虾,保持水质新鲜,可提高日本对虾和刺参的成活率,利用两者饵料和空间互补性,可显著提高虾池的利用率和经济效益.  相似文献   

7.
Two experiments were conducted to evaluate the addition of astaxanthin from red yeast, Xanthophyllomyces dendrorhous, in the diets of goldfish, Carassius auratus. The first was designed to investigate the distribution of pigments in different tissues of goldfish and the effect of astaxanthin in the diet. The carotenoid concentration of tissues was not homogenous. The content of pigments in fish caudal fin was the highest followed by those of scales and head. Flesh had the least carotenoid deposition. Fish fed the diet containing 60 mg/kg astaxanthin had increased concentration of pigment in its head (22.6%), scales (45.5%), flesh (31.0%), and fin (21.2%), compared to fish fed basal diet (P < 0.05). Sixty parts per million astaxanthin had no effect on the weight gain and survival rate. High‐performance liquid chromatography analysis showed astaxanthin in its esterified form in goldfish. The second experiment was aimed at determining the dietary level of astaxanthin that improved color of goldfish. Goldfish were fed the same diet supplemented with 0, 10, 20, 40, 60, and 80 mg yeast astaxanthin/kg for 60 d. The deposition of carotenoids in goldfish fed diets supplemented with astaxanthin increased significantly (P < 0.05) after 15 d of feeding compared to that of the fish fed the diet without astaxanthin, but the effect of dosage of astaxanthin in the diets on the color of goldfish was not completely evident until Day 60 (P < 0.05). During the period of 15–45 d, the deposition of pigments in fish did not increase significantly (P > 0.05) in any treatment with the exception of the diet with 40 mg yeast astaxanthin/kg.  相似文献   

8.
The effects of feeding different sources of brine shrimp nauplii with different fatty acid compositions on growth, survival, and fatty acid composition of striped bass, Morone saxarilis and palmetto bass (M. saxatilis x M. chrysops) were determined. The sources of brine shrimp were Chinese (CH), with a high percentage of 20:5(n-3), eicosapentaenoic acid (EPA), and Colombian (COL), San Francisco Bay (SFB), and Great Salt Lake (GSL), with low percentages of EPA but high percentages of 18:3(n-3), linoienic acid. None of the brine shrimp sources contained a measurable amount of 22:6(n-3), docosahexaenoic acid (DHA). After enrichment with menhaden oil to increase the content of EPA and DHA, the GSL brine shrimp nauplii were also fed to hybrid striped bass.Growth and survival of fish larvae fed brine shrimp nauplii with high percentages of EPA and DHA (CH and GSLE) were higher (P < 0.05) than those of fish fed brine shrimp with a low percentage of EPA (COL, SFB, and GSL). The ratio of 20:3(n-9) eicosatrienoic acid (ETA), to DHA in polar lipids (phospholipids) of fish, traditionally used as an indicator of essential fatty acid (EFA) sufficiency of the diet, was not a reliable indicator of essential fatty acid sufficiency of diets for larval striped bass and hybrid striped bass. However, the ratio of ETA to EPA appears to be an appropriate indicator. An ETA-to-EPA ratio in phospholipids of less than 0.10 is consistent with an EFA sufficient diet.  相似文献   

9.
《水生生物资源》1998,11(6):403-409
The reproductive performance of pond tiger shrimp given astaxanthin (100 mg·kg−1) and/or vitamin A (20 000 IU·kg−1) for 61 d in tanks was assessed in a 2 × 2 factorial experiment in a completely randomized design. Tissue carotenoid (total carotenoid; astaxanthin free form, AF; monoester, AM; diester, AD) was analyzed using high performance liquid chromatography. The gonad index (GI) of shrimps fed diets with astaxanthin and/or vitamin A (3.05 ± 0.11 to 3.30 ±0.17) were significantly higher than shrimps not fed any supplement (2.24 ± 0.17). A significant interaction between astaxanthin and vitamin A for ovarian development and spawning was detected (GI, 3.18 ± 0.14). The ovarian total carotenoid (10.85 ± 1.52 μg·g−1) and astaxanthin (AF, 7.65 ± 1.43 μg·g−1; AM, 0.63 ± 0.12 μg·g−1) content of shrimps fed a diet with astaxanthin supplement were significantly higher than those without. In shrimps fed diets with and without vitamin A, no differences in ovarian total carotenoid (9.38 ± 0.58 μg·g−1) and AF (8.12 ± 1.55 μg·g−1) content were observed except for AM (0.64 ± 0.15 μg·g−1) content. In contrast, the ovarian AD level was significantly higher (1.14 ± 0.3 μg·g−1) in shrimps fed diets with both supplements compared to other diets. A significant interaction between astaxanthin and vitamin A was detected for AD storage. In the hepatopancreas of shrimps fed diets with or without astaxanthin or vitamin A, no significant differences in AF and AM content was observed. On the other hand, the AD (4.92 ± 1.3 μg·g−1) level in the hepatopancreas of shrimps fed diet with vitamin A was significantly higher than those without. These results suggest the involvement of astaxanthin in P. monodon reproduction and its need for inclusion in broodstock diets. Supplementation of vitamin A to broodstock diet of P. monodon appears to enhance its ovarian development and spawning.  相似文献   

10.
The effect of dietary astaxanthin on growth, survival, and stress tolerance was determined in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed four isoenergic and isonitrogenous diets containing four supplemented levels of astaxanthin (0, 100, 200, and 400 mg/kg diet, respectively). Shrimp fed diets containing 100, 200, and 400 mg astaxanthin/kg diet for 30 d showed higher weight gain (WG, %) and survival compared to the control (without supplementation of astaxanthin). Specific growth rate (SGR, %/day) and final body wet weight (FBW, mg) showed the same pattern as WG. There were no significant differences in growth performance (FBW, WG, and SGR) among the groups fed the diets with astaxanthin supplementation at the termination of feeding trial. Survival of shrimp in the control and 100 mg/kg diet treatments was significantly lower than that of shrimp in the treatments with 200 and 400 mg/kg diet. After 9 d of a stress tolerance test, survival of shrimp in the 200 and 400 mg astaxanthin/kg treatments was significantly higher than that of shrimp in the 0 and 100 mg astaxanthin/kg treatments (P < 0.05). We concluded from this experiment that astaxanthin was a necessary ingredient for the development of larval L. vannamei. Considering the effect of astaxanthin on both, growth performance and survival of postlarval L. vannamei, the level of astaxanthin supplemented in the diet should be between 100 mg and 200 mg/kg of diet.  相似文献   

11.
Abstract. A feeding experiment was conducted in aquaria to evaluate growth, survival and food consumption by paddlefish, Polyodon spathula (Walbaum), fry fed live Daphnia pulex, brine shrimp nauplii, Artemia sp. (L.), from two different geographical sources, or one of three commercial dry diets. Fry were fed from first feeding (day 8 post-hatch) to day 17 post-hatch. All diets had similar percentages of crude protein and lipid. Fatty acid composition was similar in all diets except for Great Salt Lake brine shrimp nauplii which had a higher percentage of linolenic acid, 18:3 (n-3), and a lower percentage of eicosapentaenoic acid, 20:5 (n-3). Paddlefish fed live food organisms were significantly (P<0·05) larger than those fed non-living diets. Survival was significantly higher (P<0·05) for fish consuming live Daphnia (95·3%) than all other treatments. Percentage of fish with food in the digestive tract did not significantly differ (P>0·05) among treatments. Poorer growth and survival by fish fed prepared diets may have been due to limited digestibility of the dry diets by paddlefish.  相似文献   

12.
The carotenoid astaxanthin (Axn) plays a vital role in shrimp pigmentation, with direct influence on product quality, and forms a significant cost component of shrimp aquaculture feeds. However, the effects of dietary Axn on other measures of shrimp physiological performance are varied, and the efficiency of carotenoid uptake from the diet and deposition in shrimp tissues is poorly defined. This study fed juvenile shrimp (Penaeus monodon) diets that contained 0, 25, 50 or 100 mg kg?1 Axn for 6 weeks. Shrimp fed carotenoid‐free diets had significantly reduced colour and growth than those fed carotenoids, but survival was unaffected. Carotenoid digestibility improved as dietary carotenoid levels increased, and was 98.5% in shrimp fed 100 mg kg?1 Axn. After 6 weeks, whole body carotenoid levels were significantly depleted in 0 or 25 mg kg?1 fed shrimp, compared with those fed 50 or 100 mg kg?1 or compared with initial shrimp. This study also showed that Axn monoesters were enriched with saturated fatty acids, whereas Axn diesters were enriched with monounsaturated and polyunsaturated fatty acids. Combined, these studies demonstrate that a total dietary carotenoid intake of between 25 and 50 mg kg?1 Axn is required for normal shrimp growth and health in P. monodon. Evidence suggests that there is a functional role for the accumulation of carotenoids and the formation of specific Axn fatty acid esters, and these may be linked to the metabolism, storage, mobilization or deposition of Axn within various tissues.  相似文献   

13.
The optimal concentration of a panel of individual and combined carotenoid sources on skin pigmentation in fancy carp was investigated by nine experimental diets that were formulated and supplemented with astaxanthin at 25 mg kg?1, lutein at 25 and 50 mg kg?1, β‐carotene at 25, 50 and 75 mg kg?1, and lutein combined with β‐carotene at 25 : 25 and 50 : 50 mg kg?1, while a diet without supplemented carotenoid served as a control. The results showed that serum TC of fish fed diets containing supplemented with lutein plus β‐carotene at 25 : 25; 50 : 50 mg kg?1 and lutein 50 mg kg?1 diet were higher than the other treatments (P ≤ 0.05). Serum TC of the respective treatments was 6.2 ± 2.0, 7.8 ± 3.3 and 7.3 ± 1.9 μg mL?1 serum, respectively. Fish fed diets combined with lutein and β‐carotene at 25 : 25, 50 : 50 mg kg?1 and lutein 50 mg kg?1 diet had serum astaxanthin concentrations similar to fish fed the diet with astaxanthin alone at 25 mg kg?1. Serum astaxanthin concentrations was 0.7 ± 0.01, 0.9 ± 0.01, 0.4 ± 0.02 and 1.7 ± 0.18 μg mL?1 serum, respectively. The chromaticity of fish body skin of red and white position was assessed by colourimetry using the CIE L*a*b (CIELAB) system. Pigmentation response of skin redness of fancy carp fed with diets combined with lutein and β‐carotene at 25 : 25, 50 : 50 mg kg?1 and lutein 50 mg kg?1 were higher than other treatments (P ≤ 0.05) but they were similar to fish fed with 25 mg kg?1 astaxanthin diet. The redness (a* values) of fish fed diets with diets combined with lutein and β‐carotene at 25 : 25, 50 : 50 mg kg?1 and lutein 50 mg kg?1 were 28.3 ± 0.53, 29.9 ± 1.38, 28.8 ± 3.95 and 28.5 ± 2.49, respectively. After 3 weeks of feeding the experimental diets, the fish fed on a diet without carotenoid supplement for one week demonstrated that the same three groups still retained their redness and had an overall tendency to improve skin colouring. Finally, concentrations 50 mg kg?1 of lutein, or the combination of lutein and β‐carotene at 25 : 25 mg kg?1 showed the highest efficiency for improving skin pigmentation and redness of skin.  相似文献   

14.
Abstract

Three experiments were conducted. In Experiment 1, the acceptance time of pelleted diets sprayed with fresh palm fruit extract (FPFE), commercial palm oil (COM), or a control diet to African catfish, Clarias gariepinus, fingerlings was investigated. In Experiment 2, the effects of five diets on growth and survival of African catfish larvae were determined: (1) bambara nut waste-based (BW) diet; (2) bambara nut waste-based diet with 5% of diet formula of FPFE (BWP); (3) bambara nut waste-based diet with 5% of diet formula of FPFE plus 1.5% of diet formula of Spirulinapowder (BWPS); (4) fish waste-based diet (FWP); and (5) brine shrimp, Artemiasp., nauplii (control). In the BWP, BWPS, and FWP diets, fresh palm fruit extract was sprayed on the diets as a feed attractant. The Spirulinapowder was included in BWPS as an additional attractant. In Experiment 3, the effects of seven diets on growth and survival of the African catfish larvae were investigated: (1) BW; (2) BWP; (3) FWP; (4) a bambara waste-based diet with 5% COM (BWC); (5) a fish waste-based diet with 5% of formula as COM (FWC); (6) a fish waste-based diet with neither FPFE nor COM, and (7) brine shrimp nauplii (control). African catfish finger-lings accepted the pellets containing FPFE in significantly less time (P < 0.01) than they did the other pelleted diets. Inclusion of FPFE as 5% of diet formula significantly (P<0.05) improved the growth and survival of African catfish larvae fed formulated diets. Inclusion of Spirulinaat 1.5% of diet formula had no effect. Brine shrimp was nutritionally superior to the formulated diets for the African catfish larvae during the first 28 days of feeding. The results indicate that FPFE can be added to a diet for African catfish at 5% of diet formula. However, brine shrimp nauplii fed to larvae had the highest percentage survival and highest growth rates of any of the treatments.  相似文献   

15.
The aim of this work was to investigate the effect of different carotenoid sources/concentrations and temperature on goldfish (Carassius auratus) skin pigmentation. In the first trial (trial A), the effect of carotenoid source (natural – microalgae Chlorella vulgaris and synthetic – Carophyll Pink) and carotenoid concentration (45, 80 and 120 mg pigment kg?1 diet) was tested. Six homogeneous duplicate groups of juvenile goldfish (7.4 g) were fed, for 5 weeks, one of the diets containing 45, 80 or 120 mg of total pigments of C. vulgaris biomass or synthetic astaxanthin per kg of diet (Cv45, Cv80, Cv120, Ax45, Ax80, Ax120), respectively. In trial B, the effect of water temperature on skin pigmentation was studied. Five homogeneous duplicate groups of 25 goldfish each (5.2 g) were fed diet Ax45 over 9 weeks, to test the following temperatures: 22, 24, 26, 28 and 30 °C. At the end of both trials, samples of skin along the dorsal fin were withdrawn for subsequent analysis of total carotenoid content, intensity of colour, red and yellow hue and visual observation. The best carotenoid concentrations were achieved with astaxanthin diets. There was a tendency to an overall improvement of colour parameters (L and b) in fish fed diets with high levels of C. vulgaris. The results indicated that the best temperature range to maximize skin pigmentation was 26–30 °C.  相似文献   

16.
A prepared shrimp food was impregnated at 3% by weight with oil extracted from heads of Penaeus setiferus. This procedure brought about a reduction in the level of ω6 fatty acids and an increase in the percentages of ω3 fatty acids and saturated acids in the diet.The lipid-augmented ration was fed to juvenile Macrobrachium rosenbergii for 12 weeks in the laboratory, with the unmodified diet as a control. Prawns fed the augmented diet grew significantly larger than those given the control feed, and this difference was apparent by the sixth week of the study. Final mean biomass (g prawn/m2 of tank floor) and efficiency of food utilization in the experimental group were about twice that in the control. Survival in the two groups was similar throughout the study and averaged 71 and 68%, respectively, for the experimental and control animals at the end of the experiment.Prawns fed both rations contained in their tissues about the same percentage of ω3 fatty acids as their diets, indicating conservation of these dietary acids and/or biosynthesis. In contrast, the animals contained substantially less 18:2ω6 (linoleic acid) than their diets, and the data suggested that some of this fatty acid may have been utilized as an energy source. Also, animals fed the augmented diet contained about 15 times more carotenoid pigments than those given the control ration.The study suggests that ω3 fatty acids are important in the nutrition of M. rosenbergii and that prawn diets might be made more effective by increasing the relative proportion of ω3 fatty acids in their composition. Waste shrimp heads may be one suitable source of fatty acids and pigments for use in prepared diets for aquaculture.  相似文献   

17.
本研究旨在探讨不同饵料对海蜇(Rhopilema esculentum)幼体生长、消化酶、抗氧化酶和非特异性免疫酶活力的影响.实验设置4个饵料组:小球藻组、虾片(对虾开口饵料)组、卤虫无节幼体组和混合组(卤虫无节幼体和虾片等比例混合),养殖实验持续进行30 d.结果显示:混合组和卤虫无节幼体组海蜇的增重率(WGR)和特...  相似文献   

18.
This study was performed to assess the nutritional value of Streptocephalus dichotomus nauplii and compared with standard larval diet and parthenogenetic strain of Artemia nauplii. The effectiveness of live feed was determined by feeding freshwater prawn Macrobrachium rosenbergii postlarvae. Results on the growth rate, weight gain, survival, fatty acid and amino acid composition show a significant variation between the dietary treatments. Mean larval growth was significantly different ( P  < 0.001) between control diet (13.5 ± 0.5 mm) and live feeds ( Streptocephalus nauplii; 18.4 ± 0.5 mm and Artemia nauplii 18.7 ± 0.2 mm). The weight of larvae-fed Streptocephalus (41.1 ± 1.44 mg) and Artemia nauplii (41.7 ± 0.2 mg) was not significantly different; however, treatment with live feeds was significantly higher than the control (16.3 ± 0.5 mg) ( P  < 0.001). Proximate composition on the fairy shrimp reveals that they are rich in protein, lipid, essential amino acids (EAA) and essential fatty acids (EFA). The polyenoic unsaturated fatty acid (18 : 2 n-6 and 18 : 3 n-3) and highly unsaturated fatty acid (20 : 4 n-3 and 20 : 5 n-3) show a dramatic increase in larval tissue relative to its proportional composition in the live diets. Amino acid composition in the live feeds, Streptocephalus and Artemia nauplii, perfectly reflects on the amino acid proportions in the larvae-fed diets which confirm its utilization.  相似文献   

19.
An 18-week study was conducted to examine growth characteristics of the juvenile blue crab (Callinectes sapidus Rathbun) fed various levels of dietary protein. Hatchery raised individuals (157) of identical age (160 days) from the same gravid female were assigned to one of four dietary treatments: adult brine shrimp (Artemia salina Leach) and artificial pelleted diets containing crude protein levels of 23, 37, and 49%.Growth rate, measured as a function of mean weight and mean carapace width, indicated that brine shrimp-fed crabs were larger (P < 0.05) than crabs fed artificial pelleted diets. Also, blue crabs fed either 37 or 49% crude protein were larger than crabs fed the 23% crude protein diet. Molting frequency was greater in the brine shrimp-fed crabs than in those fed the artificial diets. No differences in growth were detected when comparing males vs. females fed the artificial diets. However, females demonstrated greater growth than males within the brine shrimp treatment. Protein concentration of freeze-dried whole blue crab carcasses was greater in brine shrimp-fed crabs than in crabs fed the artificial pelleted diets (P < 0.05).  相似文献   

20.
Pacific white shrimp Litopenaeus vannamei (1050 individuals with initial weight of 1.01 ± 0.001 g) were fed either control diet or one of six dietary astaxanthin (AX) concentration (25, 50, 75, 100, 125 and 150 mg kg−1) diets for 56 days in 35 tanks (30 shrimp per tank). After 56 days of culture, shrimp‐fed AX125 and AX150 diets had higher (< 0.05) weight gain, specific growth rate, total antioxidant status and lower (< 0.05) superoxide dismutase (SOD), catalase (CAT) than shrimp fed control diet. After low dissolved oxygen stress for 1 h, survival rate of shrimp fed AX75, AX100, AX125 and AX150 diets was higher (< 0.05) than that of shrimp fed control diet. Hypoxia inducible factor‐1α (HIF‐1α), cytosolic manganese superoxide dismutase (cMnSOD) and CAT mRNA expression levels of shrimp fed seven diets were significantly down‐regulated under hypoxia than under normoxia, but their expression levels were higher under hypoxia in shrimp fed AX‐supplemented diets than in shrimp fed control diet. About 70‐kDa heat‐shock protein (Hsp70) mRNA expression level of shrimp fed seven diets was significantly up‐regulated under hypoxia than under normoxia, but its expression level was lower under hypoxia in shrimp fed AX‐supplemented diets than in shrimp fed control diet.  相似文献   

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