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1.
Two experiments were conducted to determine if two proposed crustacean reference diets, BML 81S or HFX CRD-84, could serve as nutritional standards for early postlarval stages of the Caribbean king crab Mithrax spinosissimus or the spiny lobster Panulirus argus . In the first study, after an eight week trial period, survival of postlarval crabs (initial mean weight = 20 mg) was higher ( P < 0.05) for crabs fed a control diet of commercial larval fish feed (66.7%) or BML-81S (45.8%) than for crabs fed HFX CRD-84 (16.7%). Final mean weight was also greater ( P < 0.05) for crabs consuming the fry feed than for crabs fed BML-81S or HFX CRD-84 (710 vs. 460 and 340 mg, respectively). In the second study, after a ten week trial period, survival of second stage postlarval spiny lobsters (initial mean weight = 0.20 g) was greater ( P < 0.05) for animals fed live adult Artemia (93.3%) than for lobsters fed HFX CRD-84 (26.7%) or BML-8lS (0%). Lobsters offered the casein-based BML-81S did not consume the feed and died within 25 days. Results suggest that BML-81S may be an acceptable reference diet for Mithrax spinosissimus , but that neither BML-81S nor HFX CRD-84 is adequate for the early postlarval stages of Panulirus argus .  相似文献   

2.
We conducted large‐scale production trials in Seward, Alaska, USA to investigate effects of dietary astaxanthin supplementation on survival, growth and shell colouration of recently settled juvenile (C1–C4) red king crabs (Paralithodes camtschaticus). We supplemented a control diet of commercial crustacean feeds with astaxanthin, and fed these diets to juvenile king crabs at densities of 2000 and 4000 crabs m?2 for 56 days. We assessed survival and growth by counting crabs and individually measuring carapace width and weighing crabs at the start and end of the experiment, and quantified crab colour (hue, saturation, brightness) in digital photographs. Diets containing astaxanthin had higher survival, suggesting that astaxanthin may provide nutritional or immune system benefits. Crabs had lower hue, higher saturation and lower brightness values when fed diets containing astaxanthin, suggesting that red king crab colouration is plastic and responds to diet. Astaxanthin is likely an important dietary component for hatchery or laboratory reared red king crab juveniles, and should be considered for aquaculture and other rearing of this and possibly other crustacean species.  相似文献   

3.
Obtaining reliable results from comparative crustacean nutrition studies requires a dietary reference protein which is available world-wide and is nutritionally optimal for growth and survival. Traditional protein sources include "vitamin free" casein, egg albumin, whole egg protein, soybean protein, and others. These have proven to be inadequate for juvenile lobster ( Homrus americanus ). Purified rock crab ( Cancer irroratus ) protein is proposed to be nutritionally superior to casein for inclusion in semi-purified lobster diets.
Eighteen week feeding trials with juvenile H. americanus were conducted to compare diets containing protein obtained from rock crabs ( Cancer irroratus ), and produced by several different purification processes with a control diet having casein as its primary protein source. Diets containing purified rock crab protein were found to be superior to the control diet. Among the differently derived purified rock crab protein products, the precooked, isopropanol-purified was the most effective dietary ingredient.  相似文献   

4.
Juvenile Australian freshwater crayfish ( Cherax tenuimanus ) were individually housed in an experimental battery system and fed HFX CRD 84 and BML 81 S, two proposed standard reference diets for studies of crustacean nutrition. The HFX CRD 84 diet was accepted more readily than the BML 81 S diet. After 100 days, mean weight gain of marron fed the HFX CRD 84 diet was significantly greater than that of those fed the BML 81 S diet. Growth rate, measured 118 percent weight pin per ecdysis, declined during three successive 50 day periods. Growth on the proposed reference diets ranged from 16 to 33% of that achieved with pond raised marron of similar age. Both diets may be useful in the development of species specific modifications relative to nutrient composition.  相似文献   

5.
This study was conducted to investigate the effects of dietary docosahexaenoic to eicosapentaenoic acid (DHA/EPA) ratios on growth performance, survival and fatty acid composition of juvenile swimming crab (Portunus trituberculatus). Four isonitrogenous and isoenergetic experimental diets were formulated to contain different DHA/EPA ratios (0.70, 0.84, 1.06 and 1.25). There were three replicates (15 crabs per replicate) for each diet treatment. The crabs were fed (about 6–8% body weight) twice daily for 8 weeks. A good growth performance and feed utilization were observed in swimming crabs fed the diets with DHA/EPA ratios of 0.70 and 0.84. Crabs fed diet with 0.70 DHA/EPA ratio showed a significantly higher weight gain (WG) compared with the crabs fed the diet with DHA/EPA ratio of 1.25 (P < 0.05). The result of this study showed that the survival increased with decreasing the ratio of DHA/EPA. The DHA/EPA ratios in polar lipid from tissues were influenced by the dietary DHA/EPA ratios. Results of this study indicated that the growth performance and survival of juvenile swimming crab are correlated to the DHA/EPA ratio in the diets, and the best growth performance and survival were achieved with the ratios of 0.70–0.84.  相似文献   

6.
A 30‐day experiment was conducted to investigate the effect of phospholipids (PLs) on growth performance, survival, fatty acid profile and gene expression of the early juvenile (C1) swimming crab (Portunus trituberculatus). Five semi‐purified diets were formulated with graded PLs levels (0%, 1%, 2%, 4% and 8%). Each diet was fed to four replicates of crabs (30 crabs per replicate, initial weight: 8.4 ± 0.1 mg). In this study, crabs fed diets with 2%, 4% and 8% PLs had significantly higher survival rates than crabs fed with 0% and 1% PLs. Crabs fed diets with 0% and 1% PLs had significant lower weight gain (WG) than crabs fed with 8% PLs. But crabs fed with diets containing 2%, 4% and 8% PLs showed no significant difference in WG. Besides, the content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in whole body was higher than that in diets, but the monounsaturated fatty acids (MUFA) content showed an opposite trend. The EPA and DHA content in whole body increased with the increase in dietary PLs. Moreover, the moulting number increased with the increasing dietary PLs levels, the lowest moulting number was observed in crabs fed diets without supplementation of PLs. The ecdysteroid receptor (EcR) was found to be significantly up‐regulated by PLs levels. This study demonstrated that 2% PLs could meet the requirement of early juvenile (C1) swimming crab based on the growth and survival. And 4%–8% PLs supplemented in diets could reduce the leaching of feed.  相似文献   

7.
Four iso‐nitrogenous and iso‐lipidic diets were designed to investigate the effects of dietary phospholipids (PL) levels (with 0%, 1%, 2%, and 4% PL supplementation) on growth performance, lipid metabolism, and antioxidant capacity in early juvenile green mud crab (Scylla paramamosain). There were three replicates of 28 crabs (initial body weight from 42.02 to 42.44 mg) for each diet treatment, and growth trial lasted for 8 weeks. At the end of the growth trial, there was no significant difference in survival among all treatments. Crabs fed diet with 2% PL obtained highest weight gain (WG) and specific growth rate than other crabs. The molting frequency was not affected by different dietary PL addition. Besides, the contents of whole body lipid and long chain highly unsaturated fatty acids significantly increased with elevating dietary PL levels. In the hepatopancreas, crabs fed diet with 0% PL had significantly higher malondialdehyde concentration than other crabs. And crabs fed diet with 2% PL obtained significantly higher superoxide dismutase activity than crabs fed diets with 0% and 4% PL. Moreover, the mRNA expression of Na+/K+‐ATPase was significantly down‐regulated with dietary PL supplementation over 2%. Based on the second order polynomial regression analysis of WG, 2.37% dietary PL level was the optimal demand for early juvenile S. paramamosain. Moreover, we found crabs fed diet with 2% PL obtained better antioxidant capacity than other crabs.  相似文献   

8.
This study investigated the effects of different types of diet and sediment on the growth parameters of juvenile tiger crab Orithyia sinica under laboratory conditions, focusing on survival, growth and moulting. In the first set of experiments, juvenile tiger crabs were reared with five different types of sediment, i.e., soft sand, coarse sand, soft sand mixed with coarse sand, mud or bare bottom. Soft sand resulted in not only the highest survival rate of 78% but also the best rate of growth and feed intake. Crabs reared with a mud substrate showed the worst results in these parameters. The intermoult period, however, was not affected by sediment types. In the second set of experiments, crabs were fed different types of diet to determine their effects on the same growth parameters. Diets were composed of different combinations with Manila clam (Ruditapes philippinarum), brine shrimp (Artemia nauplii), microencapsulated feeds and marine diatom (Chaetoceros gracilis). Survival and growth in crabs fed Manila clam as a diet component were significantly higher than in those on other diets. The highest survival and growth were achieved with a diet that included all four components. These results provide valuable information on the appropriate bottom substrates and diet types necessary for artificial mass culture of the tiger crab.  相似文献   

9.
Feeding experiments were conducted using amino acid test diets to determine the optimal dietary requirement for arginine and lysine of the Chinese mitten-handed crab Eriocheir sinensis juvenile. Crab megalopae with an average weight of 6.86 mg were randomly assigned to different tanks and reared on six experimental diets for 25 d. The six experimental diets were formulated for different combinations of arginine (0, 0.4, 0.8, 1.2, 1.6, and 2.0 g per 100-g diet) and lysine (0, 0.3, 0.6, 0.9, 1.2, and 1.5 g per 100-g diets), respectively. Survival and molting frequency were calculated at the termination of feeding trials. Optimal arginine and lysine requirements were determined by the diets at which the highest survival and molting frequency was reached. The highest survival and molting frequency were 41.75% and 2.4, respectively, and were reached when the crabs were fed with 2% arginine. After juveniles were fed with the diets with 2.55% lysine, survival was the highest (44.0%) and the molting frequency was 2.31. We suggest that the requirement of juvenile crabs for arginine is 2.0% in diet or 3.3% of dietary protein, and the requirement for lysine is 2.55%, in diet or 4.25% of dietary protein. This study provides critical information in formulating cost-effective aquaculture diets for the Chinese mitten-handed crab juvenile.  相似文献   

10.
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   

11.
Vitamin E supplement is important in protecting lipid oxidation and enhancing immunity of aquatic animals. A 10‐week feeding trial was conducted to evaluate the effect of dietary lipid and vitamin E on juvenile Chinese mitten crab Eriocheir sinensis. The experimental diets included three levels of vitamin E (0, 100 and 300 mg kg?1) and two levels of lipid (6% and 9%). The 9% lipid diet significantly enhanced the body lipid of crabs compared with the 6% lipid diet. The vitamin E concentration of hepatopancreas increased with the increase in vitamin E in the diets regardless of dietary lipid levels. The hepatopancreas fatty acids, especially polyunsaturated fatty acid and highly unsaturated fatty acid, were significantly enhanced by vitamin E supplement or 9% dietary lipid. Vitamin E supplement significantly increased the total antioxidant capacity, superoxide dismutase, lysozyme and phenoloxidase activities of crabs compared with those fed the diets without vitamin E supplement. The hepatopancreas malondialdehyde of crabs fed 100 mg vitamin E kg?1 was significantly lower than those fed 0 or 300 mg vitamin E kg?1. The phenoloxidase activity of crabs fed the 9% lipid diet was significantly higher than those fed 6% lipid, irrespective of vitamin E levels. Vitamin E supplementation increased the bacterial resistance of juvenile crab. This study indicates that dietary lipid and vitamin E supplement do not affect crab growth and survival, but vitatmin E supplement at 100 mg kg?1 can enhance immunity and antioxidant capacity of crab fed 6% or 9% dietary lipids.  相似文献   

12.
用蛋白质水平分别为31.45%,36.37%,41.55%,46.13%,51.72%和56.86%的6种等能饲料,对初始体重为(11.86?0.11)mg的拟穴青蟹(Scylla paramamosain)幼蟹进行为期3周的养殖实验,考察饲料蛋白质水平对拟穴青蟹幼蟹生长性能、体成分以及消化酶活性的影响,以期获得拟穴青蟹幼蟹饲料蛋白质的适宜添加量。结果表明,饲料蛋白质水平对拟穴青蟹幼蟹的成活率影响不显著(P0.05);幼蟹的增重率和特定生长率随饲料蛋白质水平的提高先显著升高(P0.05)后稍有下降,最大值出现在蛋白质水平为51.72%的实验组;随着饲料蛋白质水平的提高,幼蟹粗蛋白质含量显著升高(P0.05)后趋于稳定,粗脂肪含量显著降低(P0.05),灰分含量先显著升高(P0.05)后显著降低(P0.05),水分含量则没有显著变化(P0.05);随着饲料蛋白质水平的提高,幼蟹蛋白酶活性显著升高(P0.05),淀粉酶活性显著降低(P0.05),各组脂肪酶活性也有显著差异(P0.05),但没有明显的变化规律。本研究条件下,饲料蛋白质水平在41.55%~56.86%,拟穴青蟹幼蟹均表现出较好的生长率,增重率和蛋白质水平的回归分析表明,幼蟹饲料蛋白质适宜水平为49.03%。  相似文献   

13.
青蟹属（Scylla）有锯缘青蟹（Scylla serrata），拟穴青蟹（S．paramamosain），紫螯青蟹（S．tranquebarica）和榄绿青蟹（S．olivacea）等4个种。我国以拟穴青蟹占绝对优势，它有个体大、生长快、适应性强、肉味鲜美、营养丰富等特点，已成为具有重要经济价值的海水养殖蟹类之一。  相似文献   

14.
An international cooperative effort to evaluate two possible Standard Reference Diets (SRD) for crustaceans was initiated at an informal discussion on crustacean nutrition during the 1984 World Mariculture Society (WMS) meeting in Vancouver, B.C. One diet, BML 81 S, was developed at the Bodega Marine Laboratory, University of California, Davis. The other, HFXCRD 84, was developed at the Halifax laboratory, Department of Fisheries and Oceans, Canada. Details of the formulation, preparation and proximate composition of the diets are provided. Both of these diets, which had been used to culture lobster, Homarus sp., were compared with the usual control diets of several research teams from different countries in feeding trials with many different species of crustaceans including freshwater and marine shrimp, prawn, lobster, crayfish and crab.
The preliminary data on growth and survival of Pandalus danae, Penaeus monodon, P. stylirostris, P. vannamei, P. brasiliensis, P. setiferus, P. aztecus and Homarus americanus suggest that either BML 81 S or HFX CRD 84 would be an acceptable SRD for these species. The only species tested that would not accept either diet were Panulirus argus and Cherux tenuimanus . Use of an SRD will provide a more accurate assessment of non-nutritional growth factors and permit comparisons among laboratories, species and experiments.  相似文献   

15.
A 56‐day feeding trial was conducted to investigate the effect of dietary cholesterol (CHOL) levels on growth performance, body composition and gene expression of juvenile mud crab (Scylla paramamosain). Four isonitrogenous and isoenergetic diets were formulated with 0.4%, 0.8%, 1.2% and 1.6% CHOL supplemented, and the final dietary CHOL concentrations were 0.72%, 1.11%, 1.49% and 1.83% respectively. Each dietary treatment was performed with three replicates (28 crabs per replicate, initial body weight 0.04 g). At the termination of the experiment, although the survival had no statistic difference in all treatments, the mud crabs fed the lowest CHOL diet had the lowest survival rate. The weight gain (WG) of mud crab significantly increased with dietary CHOL level up to 1.11% and then significantly decreased with dietary CHOL level further increased. The total‐cholesterol (T‐CHOL) content in whole body had an increasing trend with the dietary CHOL level increased. Besides, dietary CHOL supplement generally increased the hepatic superoxide dismutase (SOD) activity, and the mud crabs fed diets CHOL1.11 and CHOL1.49 showed significantly higher value than those fed other diets. The hepatic aspartate aminotransferase (AST) activity decreased slightly with dietary CHOL level up to 1.11% and then significantly increased with CHOL level further increased. The mRNA expression of ecdysone receptor (EcR) gene in the eyestalk obviously increased with dietary CHOL level up to 1.11% and then significantly decreased with dietary CHOL further increased. These results suggested that about 1.11% dietary CHOL seem fulfil to maintain good growth performance and healthy condition for juvenile S. paramamosain.  相似文献   

16.
The protein requirement of juvenile mud crab Scylla serrata (body weight=0.25±0.051 g, carapace width=9.3±0.04 mm) fed with different iso-energetic, iso-lipidic diets with graded protein levels (15–55% crude protein at 5% intervals) was determined. The feeding trial was conducted for a period of 63 days to determine the minimum and optimum protein requirement of juvenile S. serrata . The crabs fed with 15% and 20% dietary protein levels showed 100% and 12.5% of mortalities respectively. The mortalities observed in the above treatments were associated with the prolonged intermoult duration (46 and 32 days respectively). All other treatments recorded 100% survival. The best growth performance as well as the nutrient turn-over was recorded in crabs fed with 45% crude protein in the diet. Second-order polynomial regression of specific growth rate (SGR) as well as body protein gain vs. dietary protein levels suggested that 46.9–47.03% dietary protein is required for the best growth response and protein deposition in juvenile S. serrata . An extrapolation of 'SGR' and 'daily protein gain' upon the 'dietary protein level' axis ( Y =0) showed that 14.7–16.2% dietary protein is necessary for the minimum maintenance metabolism.  相似文献   

17.
Precocious puberty is one of the major constraints to the further development of Chinese mitten crab (Eriocheir sinensis) farming industry. Although dietary phospholipids (PL) and highly unsaturated fatty acids (HUFA) supplementation have been shown to enhance the growth of larval E. sinensis in other studies, it is still unknown whether this also leads to a higher precocity rate for juvenile E. sinensis. This study was conducted to investigate the effects of dietary PL and HUFA on precocity, survival, growth and hepatic lipid composition of juvenile E. sinensis. Two diets were formulated with PL [3.95% dry weight (DW)] and HUFA (0.98% DW) supplementation (diet A) and without PL and HUFA supplementation (diet B) and fed to juvenile E. sinensis. Although dietary PL and HUFA levels did not significantly affect the survival and growth performance of juvenile E. sinensis, compared with crabs fed diet A, a higher precocity rate was found among juvenile E. sinensis fed diet B (P=0.051). A higher total lipid content, but significantly lower levels of HUFA and PL (P<0.05) were found in the hepatopancreas of crabs fed diet B than in those fed diet A. Meanwhile, the precocious females had significantly lower hepatosomatic index, arachidonic acid (20:4n‐6), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3) contents in their hepatopancreas when compared with that of the normal immature juveniles (P<0.05). The results suggest that the occurrence of precocious puberty among farmed juvenile E. sinensis could be reduced by the inclusion of appropriate level of dietary PL and HUFA.  相似文献   

18.
Two formulated diets were evaluated to replace live crab (C) as feed for juveniles Enteroctopus megalocyathus. Formulated diets consisted of crab paste (CP) and a mixture of freeze‐dried meals of crab and squid (C&S). After 10 weeks of feeding, the effect of each diet was analysed on productive performance, nutritional and physiological condition and immune system. Both the crab and C&S diets produced the best values for specific growth rate, feed conversion ratio and protein efficiency ratio. The diet C&S proved to be the most digestible with greatest metabolized energy. The CP diet was similar to the C diet in terms of biological value and protein apparent digestibility; nevertheless, its performance was weaker for the other indicators. Furthermore, the highest α‐amylase, lipase and alkaline proteolytic activity values were observed in octopuses fed live crab, as opposed to those fed formulated feeds. The type of diet did not affect lysozyme activity in neither mucus nor haemolymph. The production of reactive oxygen species was highest in octopuses fed CP diet. It is proposed the use of C&S diet to study the nutritional requirements and to develop an optimal formulated diet for juvenile Patagonian red octopus.  相似文献   

19.
This study examined the effects of dietary cholesterol on the survival, molting pattern, and growth of early juveniles of the blue swimmer crab, Portunus pelagicus. Seven isocaloric diets were formulated to contain cholesterol at 0 (basal diet), 2.5, 5.0, 7.5, 10, 12.5, and 15 g/kg diet dry weight. Survival ranged from 20 to 47.5%, with the highest survival recorded for crabs fed the diet supplemented with 10 g/kg cholesterol, while the lowest survival was demonstrated by crabs fed the basal diet. The highest occurrence of molt death syndrome was found for crabs fed the diet with cholesterol supplementation of 15 g/kg. A general trend of decreasing development time to the crab 3 (C3) stage was observed with increasing dietary cholesterol supplementation up to a level of 10 g/kg, but this then decreased as dietary cholesterol level was increased to 12.5 and 15 g/kg. The specific growth rates of crabs, calculated for dry weight, carapace width, and carapace length, followed a similar trend. Our results suggest that, under the current feeding conditions, a dietary cholesterol level of 10 g/kg appears to be optimal for the culture of early juveniles of P. pelagicus.  相似文献   

20.
A 10‐week feeding trial was conducted to evaluate the effects of dietary lipid sources on the growth and immune responses of Chinese mitten crab Eriocheir sinensis. Six isonitrogenous and isoenergetic diets were formulated with fish oil (FO), linseed oil (LO), soybean oil (SO), rapeseed oil (RO), coconut oil (CO) and beef tallow (BT) as the sources of lipid with five replicates each. Thirty crabs (2.35 ± 0.14 g) were stocked into each tank and fed twice daily. Weight gain and specific growth rate of crab fed the FO diet were significantly lower than those fed other diets (P < 0.05), except for crabs fed LO diet (P < 0.05). Crab fed the SO diet weighed more than those fed FO diets (P < 0.05). Serum superoxide dismutase and malondialdehyde of crab fed the FO diet were significantly higher than in other groups (P < 0.05). Crab fed the FO diet had the highest activities of serum phenoloxidase, acid phosphatase, alkaline phosphatase and lysozyme (P < 0.05). The fatty acid composition in the liver of crab reflected the change in test diets. Our results indicate that the use of dietary vegetable or animal oils can achieve similar growth performance to the use of dietary FO in Chinese mitten crab, but non‐FOs may impair crab immunity. Soybean oil is recommended as a suitable replacer for FO in Chinese mitten crab diet.  相似文献   

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