Evaluation of various diets for the optimum growth and survival of larvae of the penaeid prawn Penaeus japonicus Bate

Four types of food were tested to determine their effects on the growth and survival of larvae of the penaeid shrimp Penaeus japonicus Bate. The food types were live cells of Candida utilis (yeast), freeze-dried Candida utilis, microparticulate diet, and microencapsulated diet (commercial product). The diatom Chaetoceros gracilis was fed to larvae as a control. Two sets of experiments were carried out; the first was run in outdoor 1.5 ton tanks, and the second in indoor 1.2 ton tanks. In the outdoor experiment, the best survival and growth from nauplius to postlarva stage were obtained using microparticulate diet. During the first week of culture, freeze-dried Candida utilis resulted in the highest growth and survival among examined diets, but both factors dropped dramatically after the mysis stage. In the indoor experiment, the best growth and survival were obtained using live cells of Candida utilis from nauplius stage to end of mysis stage followed by brine shrimp. Tested diets were analysed for their contents of crude protein, total lipids, total carbohydrates, amino acid profiles and fatty acid contents.     

Dietary phosphatidylcholine requirements in larval and postlarval Penaeus japonicus Bate

Three nutritional experiments were carried out to investigate the effect of dietary phosphatidylcholine (PC) on the growth (length, weight and metamorphosis) and survival (rearing and stress) of larval and postlarval Penaeus japonicus Bate. Purified soybean phosphatidylcholine (SPC, 95% purity), hen egg-PC (EPC, 94% purity), and de-oiled soybean lecithin (DSL, PC 23% purity) were used as sources of dietary PC. The results indicated that optimal metamorphosis in larval P. japonicus was obtained at levels of 15–30 g kg^?1 of dietary SPC. Feeding trials with postlarval P. japonicus showed that low levels of dietary SPC (15 g kg^?1) were more beneficial than higher levels of SPC (30 g kg^?1) or DSL (65 g kg^?1), although early postlarvae (<3 mg dry weight) presented a higher requirement for PC than later stages. Shrimp fed the 150 g kg^?1 PC-supplemented diets exhibited significantly better resistance to salinity stress than those fed a PC-deficient diet. A high level of dietary soybean lecithin (65 g kg^?1 DSL), providing 15 g kg^?1 of dietary PC, was no more effective for young postlarvae of P. japonicus than 15 g kg^?1 of purified PC alone, which suggested that the other phospholipids (mainly phosphatidylethanolamine and phosphatidylinositol) in the soybean lecithin are not required for postlarval shrimp, at least when there is already an adequate source of PC.     

Retention efficiency and release of nutrients in the digestive tract of larval shrimp (Penaeus japonicus Bate) using different microencapsulated diets

Retention efficiency and release of the nutrients in the digestive tract of larval shrimp (Penaeus japonicus) using the diets microencapsulated with gelatin and ethyl cellulose respectively were evaluated. The microencapsulated diets were produced using the fluidized bed coating process. 7.8 % gelatin and 4.2 % ethyl cellulose to the whole microencapsulated diet were respectively adopted as coating material. After immersion in 35 ‰ NaCl solution for 1 h, the nitrogen retention efficiency was significantly lower in the diet microencapsulated with gelatin compared with the diet microencapsulated with ethyl cellulose. Free amino acid retention efficiency of the diet microencapsulated with gelatin and ethyl cellulose was 12.9, 17.2 %, respectively. The mysis II larval shrimp (P. japonicus) 10 days after hatch were fed two different microencapsulated diets for 20 days and grew significantly more than the control larval shrimp fed with Artemia and shrimp flake. The nutrient components in intermediate intestine of larval shrimp were increased gradually in the order of the control (50 % shrimp flake + 50 % Artemia), Group I (50 % diet microencapsulated with gelatin + 25 % shrimp flake +25 % Artemia), Group II (100 % diet microencapsulated with gelatin), and Group III (100 % diet microencapsulated with ethyl cellulose). This study confirmed that the microencapsulated diets with slow and controlled release characteristic in the digestive tract of the larval shrimp (P. japonicus).     

Dietary arginine requirement of juvenile kuruma shrimp Marsupenaeus japonicus (Bate)

The requirements for essential amino acids by kuruma shrimp, Marsupenaeus japonicus (Bate) have not yet been determined using the dose–response method due to poor utilization of crystalline amino acids (CAA). In a previous study, we produced coated CAA that could be used to retard leaching losses. Therefore, to determine the arginine requirement of juvenile kuruma shrimp, a growth study was conducted using test diets containing six levels of coated arginine (from 1.20% to 3.19% of diet) for 42 days. Crystalline amino acids was supplemented to correspond to the amino acid pattern in the whole body protein of the kuruma shrimp except for arginine. To reduce leaching losses, CAA were coated with carboxymethylcellulose (CMC) and diets were further bound with CMC and k‐carrageenan. Test diets were fed to triplicate groups of juveniles (0.25±0.02 g) twice a day. Proximate composition and the amino acid composition of shrimp whole bodies were analysed at the end of the feeding trial. Percent body weight gain (WG), specific growth rate, feed intake, feed efficiency ratio and protein retention efficiency were significantly affected by the dietary arginine concentrations. Estimating the arginine requirement of kuruma shrimp using broken‐line analysis of percent WG resulted in a value of 2.66% of diet or 5.32% of protein. After correcting for leaching of arginine from the diets, the optimum dietary value of arginine for kuruma shrimp was a little lower than the estimated value.     

日本对虾与菲律宾蛤仔混养技术的研究

本文报道了日本对虾与菲律宾蛤仔混养的技术措施,结果表明:试验池投入产出比为1:3.7,经济效益显著。     

Effect of high water temperature on the survival, moulting and food consumption of Penaeus (Marsupenaeus) japonicus (Bate, 1888)

The kuruma shrimp, Penaeus (Marsupenaeus) japonicus (Bate, 1888), is a valuable aquaculture species in Queensland, Australia. The shrimp is supplied live to the Japanese market and must survive emersed transport for up to 36 h. In-transit mortality after harvest from high water temperatures (> 30 °C) has been reported by the industry, and a knowledge of the effects of high water temperature may provide important information for producers on grow-out management, timing of production and farm location. Experiments were conducted to determine the effect of high water temperature on survival, moulting and food consumption in P. japonicus. Replicated groups of 15.6 ± 0.2 g shrimp were acclimated and exposed to five temperatures, between 28 and 36 °C, for up to 28 days. Mortality was highest at 36 °C and equally lowest between 28 °C and 32 °C. Intermoult period was not significantly different for temperatures between 28 and 32 °C (19.8–15.5 days) but was significantly greater above 32 °C (27.4 days at 34 °C and > 104 days at 36 °C). There was evidence of moulting synchrony at 28 °C. Mean daily food consumption was highest at 32 °C at 2.34% of body weight, but decreased to 1.56% at 28 °C and 1.33% at 36 °C. Over the range of water temperatures examined, survival, moulting rate and food consumption were highest at 32 °C.     

Effects of water-soluble and fat-soluble choline sources on the performances of juvenile kuruma shrimp, Marsupenaeus japonicus Bate

The present study was undertaken to clarify the effect and interaction of choline chloride (CC) and phosphatidylcholine (PC), the water‐ and fat‐soluble sources of choline, on the performances of kuruma shrimp, Marsupenaeus japonicus juveniles using as response variables such as percent weight gain (%WG), specific growth rate (SGR), survival (SR%), feed efficiency ratio (FER), protein efficiency ratio (PER), proximate composition, fatty acids profile and free choline and PC contents in the whole body of kuruma shrimp. A 40‐day feeding trial was conducted as a 2 × 3 factorial experiment with six test diets containing three levels of CC (0.3, 0.6 and 1.2 g kg^?1) and two levels of soybean PC (SPC; 2 and 4 g kg^?1). Both of the choline sources (CC and SPC) showed a significant interaction (P<0.05) regarding all the evaluated response variables except for the proximate and fatty acid contents. Interestingly, there was a positive effect (P<0.05) of CC observed with increasing its level at the low level of SPC and vice versa. However, the magnitudes of the beneficial effect of CC in terms of the evaluated parameters were changed with the different dietary levels of SPC. Also, the inclusion of higher levels of SPC (4 g kg^?1) or CC (0.6 and 1.2 g kg^?1) diminished the effect of the other source.     

浙北地区利用冬闲虾塘饲养日本对虾的试验

利用饲养南美白对虾的冬闲虾塘 ,采取精养模式养一茬日本对虾 ,可提高围塘养殖的综合效益。本试验的放养密度为 2× 10 4余尾 / 6 6 7m2 ,单产 38.5kg/ 6 6 7m2 ,成活率 2 3.3%。盐度控制在 17以上     

Early weaning of winter flounder (Pseudopleuronectes americanus Walbaum) larvae on a commercial microencapsulated diet

Like most small marine fish larvae, the stomachs of winter flounder Pseudopleuronectes americanus are undeveloped at first feeding and have relatively reduced digestive capacity. This work was undertaken to test whether larvae at the onset of stomach differentiation (larval size about 5.5 mm) could be early weaned onto a commercial microencapsulated diet. We assessed the effect of early weaning by first comparing growth performance (standard length, total protein content and age at metamorphosis) of larvae fed enriched live prey from first feeding to a size of 5.5 mm and then reared on three different feeding regimes until metamorphosis: (1) live prey (LP) as a control group; (2) mixed feeding of live prey and microencapsulated diet (LP‐ME); (3) exclusively microencapsulated diet (ME) after fast weaning over 4 days (to a larval size of 6.2 mm). No differences were observed between larval development in the two first groups, which began metamorphosis at 40 days old. The larvae of the third group showed significantly slower growth that resulted in a delay of 4 days in the onset of metamorphosis. Differences in live prey availability between the treatments and the short transition period to allow the larvae to adapt to the new diet were identified as possible contributing factors to the slower growth and to the delay in metamorphosis of early weaned larvae. In a second experiment, the transitional weaning period was increased until the larvae were 6.6 mm in length. Weaning at that size resulted in no slowing of growth or delay in metamorphosis, suggesting that the feeding schedule was adequate.     

Dietary administration of Bacillus (B. licheniformis and B. subtilis) and isomaltooligosaccharide influences the intestinal microflora,immunological parameters and resistance against Vibrio alginolyticus in shrimp,Penaeus japonicus (Decapoda: Penaeidae)

The experiment was conducted to investigate the effects of oral administration of probiotics (Bacillus licheniformis and Bacillus subtilis) in combination with prebiotic isomaltooligosaccharide (IMO) on the intestinal microflora and immunological parameters of Penaeus japonicus and its resistence against Vibrio alginolyticus. A basal diet was supplemented with 0% probiotics and prebiotic (control), 10⁸ colony forming unit (CFU) g^?1B. licheniformis and 0.2% IMO (T1), 10⁸ CFU g^?1B. subtilis and 0.2% IMO (T2), 10⁸ CFU g^?1B. licheniformis in combination with 10⁸ CFU g^?1B. subtilis and 0.2% IMO (T3). The results showed that the total bacterial counts significantly increased (P<0.05) and Vibrio counts significantly decreased (P<0.05) in the intestine of shrimp with supplementation of dietary synbiotics. Shrimp fed the diet with both Bacillus probiotics and IMO (T3) produced significantly higher immune parameters (phenoloxidase activity, lysozyme activity and nitric oxide synthase activity and superoxide dismutase activity) than the control group (P<0.05). Significant lower cumulative mortality after challenge with V. alginolyticus was also observed in shrimp fed diet with both Bacillus probiotics and IMO (T3) than that in the control group (P<0.05). The results indicated that the oral administration of probiotics (B. licheniformis and B. subtilis) and prebiotic IMO has positive effects on bacterial flora in P. japonicus gut, and can activate non‐specific immunity of shrimp.     

Maturation diet based on fatty acid content for male Penaeus monodon (Fabricius) broodstock

The contents of three essential fatty acids, arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), from wild Penaeus monodon broodstock were evaluated in comparison with natural diet fed P. monodon. Spermatophores of wild male broodstock contained higher levels of AA than those of artificial diet fed males. Polychaetes had higher proportion of AA to EPA and DHA at 5.8:5.5:1 in mud polychaetes followed by 12:7:1 in sand polychaetes, while DHA was a preferential n‐3 highly unsaturated fatty acid (HUFA) in squids and fish. The experimental feed was constructed to simulate the HUFA profile of polychaetes (AA:EPA:DHA as 5:1:1) and then fed to farmed male black tiger prawn broodstock for 1 month. The results exhibited comparable reproductive characteristics to wild male suggesting the possibility of replacing wild males with pond‐reared males. Rearing farmed males in a test unit for a month did not reduce the quality of prawn sperm. Reproductive performance indices (sperm sac weight, total number of sperm, percentage of live sperm, percentage of abnormal sperm) from the males of all treatments were not statistically different except in males fed with pellets. Control (live feeds) and combined diet provided better reproductive performance in pond‐reared males. Analysis of AA, EPA and DHA in reproductive tissues, hepatopancreas and muscle of treated animals in each treatment revealed an accumulation of dietary HUFA into reproductive tissues. No evidence of transfer of HUFA from hepatopancreas or muscle to spermatophore was found.     

海水中Zn2+和Mn2+对日本对虾仔虾体内碱性磷酸酶活性的影响

分别在经过螯合剂Cephlex100处理的海水中添加Zn^2 和Mn^2 培养日本对虾仔虾，观察金属离子对其变态发育及体内碱性磷酸酶的影响。结果显示，当海水中Zn^2 为20－40μg/L时可以明显激活仔虾体内碱性磷酸酶的活性，但大于此浓度时则使该酶的活性降低；当海水添加Mn^2 时均能提高仔虾体内碱性磷酸酶的活性，浓度在40μg/L时碱性磷酸酶的活性最高，碱性磷酸酶活性的高低可作为判别环境因素是否适合对虾幼体生存的指标。     

Assessment of requirement values for essential amino acids in the prawn, Marsupenaeus japonicus (Bate)

The requirements of juvenile prawn, Marsupenaeus japonicus (Bate), 0.79 g initial body weight, for essential amino acids (EAA) were evaluated based on the daily increase of each EAA in the whole body when the prawn was maintained on a diet with a high nutritive value (a casein‐squid protein‐based diet). The quantities of each EAA needed daily for growth and maintenance of prawn are conceived to correspond to the daily requirements of this prawn species for EAA. Therefore, these requirement values of respective EAA should be supplied from dietary proteins. To determine these values, protein and amino acids of the whole body of the prawn were quantified before and after feeding experiments, and the quantities of respective EAA needed to meet the requirements were estimated based on the EAA profile of the whole body protein of prawn. As a result, the contents of EAA in dietary proteins (%) needed to meet the requirements of the prawn for EAA were assessed to be: threonine (2.3), methionine (1.3), valine (2.4), isoleucine (2.3), leucine (3.4), phenylalanine (2.6), lysine (3.2), histidine (1.1), arginine (2.9) and tryptophan (0.6), respectively, when the prawn are fed 50% protein diet with 90% protein digestibility at a ration size of 2% (% of body weight).     

海洋1号红酵母饲养日本对虾幼虾的效果

报道了在饵料中定量添加海洋 1号红酵母后 ,饲养日本对虾 (Penaeusjaponicus)幼虾的试验结果。按海洋 1号红酵母在饵料中添加量不同将试验分为 6组 ,连续投喂 14d后 ,分别测定试验和对照日本对虾幼虾的成活率、生长速度以及对环境因子的耐受力 ,比较海洋 1号红酵母在饵料中不同的添加量对日本对虾幼虾的饲养效果。试验结果表明 ,在饵料中添加海洋 1号红酵母具有提高日本对虾幼虾的成活率、促进生长和增加对环境因子耐受力的效果。     

环境因子对发光细菌的生长及日本对虾仔虾感染死亡率的影响

以水温、盐度、pH、COD、NH3－N为环境因子，哈维氏弧菌（Vibro harveyi)感染日本对虾（Penaeus japonicus）仔虾，试验进行3d。结果表明，水温、温度、pH和COD对发光细菌的生长和日本对虾仔虾的感染死亡率具有明显的促进作用。在水温30℃，盐度32．8，pH7．654和COD10．2mg／L时，发光细菌在试验结束时的数量比初始时分别增加了11．2倍，6．5倍和7．9倍；日本对虾仔虾的死亡率比对照组分别增加了60％，45％，43％和50％。NH3－N对发光细菌的促生长作用不明显，但其质量浓度1．2－1．6mg/L时，能增加日本对虾仔虾对发光病的感染率和死亡率。     

Genetic variation of wild and cultured populations of the Kuruma prawn Marsupenaeus japonicus (Bate 1888) using microsatellites

The microsatellite DNA technique was used to detect the genetic variations between wild and cultured populations of Kuruma prawn Marsupenaeus japonicus Bate 1888. All the six microsatellite loci screened in this study showed high polymorphism for their PIC (0.6701–0.8989), which was much more than the standard value of 0.5. A total of 73 alleles were observed over six loci from 93 shrimps. The mean number of allele locus ranged from 9.83 (cultured) to 11.83 (wild). The number of effective alleles varied from 6.86 (cultured) to 8.58 (wild). The average of observed heterozygosity (H_o) of populations varied from 0.6935 (cultured) to 0.7370 (wild), and that of expected heterozygosity (He) was 0.8169 (wild) and 0.8209 (cultured). Tests of Hardy–Weinberg showed that these loci deviated significantly or highly significantly in one or both populations. Compared with the wild population, the cultured population showed little reduction in genetic variation. The total number of alleles (71, 59) was not significantly (P=0.296) different between wild and cultured populations. The paired‐samples t test of observed heterozygosity and expected heterozygosity implied that there was no significant difference (P=0.572 and 0.891 respectively) between wild and cultured populations. However, some rare allele loss might have occurred in the cultured population. A total of 14 unique alleles were found in the wild population, but only two unique alleles were observed in the cultured population. Therefore, there is a need to monitor genetic variability of cultured population, and to improve the hatchery program for the conservation of wild Kuruma prawn resources.