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1.
The use of dried Artemia biomass meal as an exclusive feed for postlarval white shrimp (Litopenaeus vannamei) was compared with four commercial feeds and three crustacean meals in a series of trials. Postlarvae (PL1–PL6) were stocked at a density of 1.5–2.5/litres in 16 tanks (100 litres volume) and fed, ad libidum, five times a day, over 23–29 days. Feeding postlarval shrimp with dried Artemia biomass resulted in a significantly larger size than feeding with three of the commercial feeds, and the crustacean meals. There was no significant size difference observed in animals fed with Artemia biomass and the commercial 'Golden Pearls' feed for postlarvae, however the coefficient of variation among the size of the 'Golden Pearls' fed animals was significantly higher. The weight increase of animals fed with Artemia biomass was higher than in animals fed with all the tested feeds. The survival rate was not significantly different in animals fed with Artemia flakes from 'Salt Creek', 'Bio-Marine', 'Golden Pearls' and Artemia biomass, however the survival rate was significantly larger in animals fed with Artemia biomass than in animals fed with the crustacean meals and 'Artemac.' Results suggest that dried Artemia biomass is a well-suited feed for postlarval L. vannamei.  相似文献   

2.
Supplementation of microalgae and Artemia nauplii with practical formulated feeds containing fresh or dried Artemia biomass for larval rearing of black tiger shrimp, Penaeus monodon, was assessed. Five feeding treatments were carried out in a recirculating seawater system with fifteen 30-L fiberglass tanks. Shrimp nauplii were stocked at a density of 150 L?1 for 23 days. In the control treatment, live feed was supplemented with commercial formulated feed (Inve Aquaculture NV, Belgium). In two other treatments, live feed was supplemented with a pelleted feed based on either fresh or dried Artemia. In the remaining two treatments live feed was supplemented with a combination of 50% commercial feed and 50% fresh or dried Artemia feeds. Overall, performance of PL in the combination treatments (commercial feed and Artemia diets) were equal to or better than those fed commercial feed alone as seen by the better growth rate and higher resistance to formalin stress. The results indicate that feed containing fresh or dried Artemia biomass can partially supplement live feeds for larval rearing of P. monodon.  相似文献   

3.
An experiment was conducted to evaluate the effect of different forms of Artemia biomass as a food source on survival, molting and growth rate of mud crab Scylla paramamosain. Instar 1 crablets with a mean weight of 0.0082 ± 0.0007 g were reared both individually and communally and fed with different diets consisting of fresh shrimp meat (control feed), live Artemia biomass, frozen Artemia biomass and a dried Artemia‐based formulated feed for 40 days. The highest survival was obtained for crablets receiving live Artemia (92.5% and 75.8%) followed by the groups fed with frozen biomass (90.0% and 47.5%), the control feed (72.5% and 24.2%) and the dried Artemia‐based diet (60.0% and 21.7%) for individual and communal cultures, respectively. The intermolt period, the total number of moltings and the growth rate, which were determined on individually reared crabs, showed the same pattern as for survival. The results suggest that crab performance decreased in the following order: live Artemia>frozen Artemia > fresh shrimp meat > dried Artemia‐based formulated feed. Live Artemia biomass proved an ideal feed for nursery of Scylla paramamosain crabs. Frozen Artemia biomass may be an alternative in times of shortage. Our findings illustrate the high potential for local utilization of Artemia biomass in Vietnam for reliable production of mud crab juveniles.  相似文献   

4.
The present study was performed to evaluate the effect of using Artemia biomass, by‐product from Artemia cyst production on growth and feed utilization of goby Pseudapocryptes elongatus fingerlings. A control diet containing fishmeal as main protein source was compared with four experimental diets in which fishmeal protein was replaced by increasing dietary levels of Artemia protein, namely 25%, 50%, 75% and 100%. The five test diets were compared with a commercial diet and dried Artemia. All diets were formulated to be equivalent in crude protein (360–370 g kg?1) and lipid (58–65 g kg?1). The experiment was conducted in 80 L plastic tanks filled with water at a salinity of 15 g L?1. Goby fingerlings with 0.21 g initial weight were fed the test diets for 30 days. The results showed that weight gain and specific growth rate of goby were positively correlated with total feed intake. Moreover, growth performances and feed utilization in the fry receiving the commercial feed and fishmeal control diet were similar, both were inferior to the groups fed dried Artemia and the based formulated diets. These results illustrate that both dried Artemia and Artemia‐based feeds can be used for feeding goby fingerlings, indicating the high potential of using locally produced Artemia biomass, which could contribute to reduce the reliance on fishmeal and improve profits for Artemia producers.  相似文献   

5.
Use of ongrownArtemia in nursery culturing of the tiger shrimp   总被引：1，自引：0，他引：1  
Juvenile and adultArtemia produced in a semi flow-through culture system were used as food for postlarval shrimp. The growth performance of shrimp reared on such ongrownArtemia live prey is identical to the growth obtained when feeding newly hatchedArtemia. However, a significantly better stress resistance is obtained when the postlarvae are exposed to a low salinity in a stress test. Besides nutritional and energetic advantages, the use ofArtemia biomass for feeding postlarval shrimp also results in improved economics as expenses for cysts and weaning diets can be reduced.  相似文献   

6.
One of the major problems in the shrimp culture industry is the difficulty in producing high-quality shrimp larvae. In larviculture, quality feeds containing a high content of highly unsaturated fatty acids (HUFA) and ingredients that stimulate stress and disease resistance are essential to produce healthy shrimp larvae. In the present study, Penaeus monodon postlarvae (PL15) were fed for 25 days on an unenriched Artemia diet (control; A) or on a diet of Artemia enriched with either HUFA-rich liver oil of the trash fish Odonus niger (B), probionts [Lactobacillus acidophilus (C1) or yeast-Saccharomyces cerevisiae (C2)] or biomedicinal herbal products (D) that have anti-stress, growth-promoting and anti-microbial characteristics. P. monodon postlarvae fed unenriched Artemia exhibited the lowest weight gain (227.9 ± 8.30 mg) and specific growth rate (9.95 ± 0.05%), while those fed the HUFA-enriched Artemia (B) exhibited the highest weight gain and specific growth rate (362.34 ± 12.56 mg and 11.77 ± 0.08%, respectively). At the end of the 25-day rearing experiment, the shrimp postlarvae (PL40) were subjected to a salinity stress study. At both low and high (0 and 50‰) salinities, the group fed the control diet (A) experienced the highest cumulative mortality indices (CMI) 935.7 ± 2.1 and 1270.7 ± 3.1, respectively. Those fed diet D showed the lowest stress-induced mortality, and CMI were reduced by 31.1 and 32.3% under conditions of low and high salinity stress, respectively. A 10-day disease challenge test was conducted with the P. monodon postlarvae (PL40–PL50) by inoculating the shrimp with the pathogen Vibrio harveyi at the rate of 105–107 CFU/ml in all rearing tanks. P. monodon postlarvae fed probiont-encapsulated Artemia diets (C1 and C2) exhibited the highest survival (94.3 and 82.3%, respectively) and lowest pathogen load (V. harveyi) in hepatopancreas (5.2 × 102 ± 9.0 × 10 and 4.6 × 102 ± 9.0 × 10 CFU g−1, respectively) and muscle (2.0 × 102 ± 6 × 10 and 1.7 × 102 ± 8.6 × 10 CFU g−1, respectively) tissues. The shrimp that were fed the unenriched Artemia (Control; A) showed the lowest survival (26.33%) and highest bacterial load in the hepatopancreas (1.0 × 105 ± 5 × 103 CFU g−1) and muscle (3.6 × 104 ± 6 × 102 CFU g−1). The shrimp fed the herbal product (D)-enriched Artemia also exhibited enhanced survival and reduced V. harveyi load in the tissues tested compared to the control diet (A) group. The results are discussed in terms of developing a quality larval feed to produce healthy shrimp larvae.  相似文献   

7.
A 21‐d nursery trial was conducted to evaluate various food supplements on growth and survival of postlarval (PL) Litopenaeus vannamei. Each of four treatments was provided with an equal quantity of a dried commercial feed throughout the study. Three treatments received algae paste (Thalassiosira weissflogii) supplemented every 3 d. These include F, commercial feed plus algae; FAr3, commercial feed plus algae plus Artemia every other day during the first 7 d; and FAr7, commercial feed plus algae plus Artemia every day during the first 7 d. The fourth treatment served as control (FNA); it relied only on the commercial feed plus naturally occurring algae. At the conclusion of the nursery period, there were no significant differences in survival or feed conversion ration for PL nursed in the various treatments. Artemia did have some effect in that PL receiving Artemia supplement for 3 d (FAr3) were significantly larger than those that did not. Algal paste in itself had no significant effect. Overall, results suggest an advantage to supplementing dried feed with Artemia for at least 3 d during the first week of nursery culture but little advantage to the use of a diatom paste as a food supplement.  相似文献   

8.
Larval rearing of many marine organisms is dependent on the availability of live food. The aim of this study was to optimize larval first feeding for the mud shrimp Upogebia pusilla, by comparing the effectiveness of the two most commonly used live feeds: Brachionus plicatilis and Artemia sp. nauplii. Survival, larval duration, molt synchronism and megalop size were compared using five feeding treatments: Artemia from zoea I to IV (B0), Brachionus during zoea I and Artemia from zoea II to IV (B1), Brachionus during zoea I and II and Artemia during zoea III and IV (B2), Brachionus from zoea I to III and Artemia during zoea IV (B3) and Brachionus from zoea I to IV (B4). The proportion of larvae that reached the megalop stage was 0.00% in treatment B0, 3.33% in treatment B1, 33.33% in treatment B2, 66.67% in treatment B3 and 76.67% in treatment B4. Larvae fed on rotifers until zoea III or zoea IV stages had a higher survival but no differences were found either in time to reach megalop or in megalop size. This study demonstrates that rotifers are essential for the survival and development of U. pusilla early larval stages but that rotifers can be successfully replaced by Artemia nauplii in the zoea IV stage.  相似文献   

9.
Low-hatch, decapsulated Artemia cysts were assessed as feed for Penaeus indicus post-larvae (PL) 1–15 days old and the problems resulting from the incorporation of decapsulated cysts into compounded feeds were evaluated. Growth and survival of PL fed on decapsulated cysts (AC) were comparable with Artemia nauplii fed PL (control) and significantly (p < 0.05) higher than observed amongst PL fed on two granulated commercial diets (G150 and G300) or a commercial flake feed (AC-F) incorporating decapsulated cysts (80%). PL fed on artificial diets showed poor growth and delay in metamorphosis. However, survival of PL fed on AC-F was significantly higher (p < 0.05) than that observed amongst granulated feeds. Decapsulated cysts processed into a granulated feed (AC-G) or dried at 90°C (AC-90) also resulted in slow growth and survival when fed to PL. Overall, artificial feeds showed poor water stability and significantly higher leaching of soluble protein and carbohydrates than decapsulated cysts. AC-90 cysts also showed a high level of bursting and leaching of material. This indicates that low-hatch Artemia cysts retain a living membrane after commercial decapsulation and drying prevents loss of highly digestible nutrients, which allows PL growth equal to that on PL fed live Artemia nauplii. Survival of PL was negatively correlated with leaching of soluble protein (p < 0.05), but no correlation was observed for leaching of carbohydrates or between growth and loss of both soluble nutrients. Hence, availability of digestible protein is critical and may influence survival of early stages of post-larval development. Water stability of artificial feeds is an essential factor in promoting efficient nutrition of PL, but other aspects related to heating during processing of feeds also appear to have a deleterious effect on nutritional quality of compounded feeds. Commercially dried, encapsulated Artemia cysts from low-hatch strains remain alive and are highly nutritious for feeding early stages of post-larval prawn but even after death may support acceptable survival when incorporated into a flake diet. © Rapid Science Ltd. 1998  相似文献   

10.
The nematode Panagrolaimus sp. was tested as live feed to replace Artemia nauplii during first larval stages of whiteleg shrimp Litopenaeus vannamei. In Trial 1, shrimp larvae were fed one of four diets from Zoea 2 to Postlarva 1 (PL1): (A) Artemia nauplii, control treatment; (NC) nematodes enriched in docosahexaenoic acid (DHA) provided by the dinoflagellate Crypthecodinium cohnii; (N) non‐enriched nematodes; and (Algae) a mixture of microalgae supplemented in C. cohnii cells. In Trial 2, shrimp were fed (A), (NC) and a different treatment (NS) with nematodes enriched in polyunsaturated fatty acids (PUFAs) provided by the commercial product S.presso®, until Postlarva 6 (PL6). Mysis 1 larvae fed nematodes of the three dietary treatments were 300 μm longer (3.2 ± 0.3 mm) than control larvae. At PL1, control shrimp were 300 μm longer (4.5 ± 0.3 mm) than those fed DHA‐enriched or PUFAs‐enriched nematodes. No differences were observed in length and survival at PL6 between control larvae and those fed DHA‐enriched nematodes (5.1 ± 0.5 mm; 33.1%–44.4%). Shrimp fed microalgae showed a delay in development at PL1. This work is the first demonstration of Panagrolaimus sp. suitability as a complete substitute for Artemia in rearing shrimp from Zoea 2 to PL6.  相似文献   

11.
The aim of this study was to evaluate the use of Gracilaria cervicornis meal as a partial substitute for the industrial feeds used in shrimp (Litopenaeus vannamei) farming. A total of 90 L. vannamei juveniles (0.34 g) were assigned randomly into nine experimental units at a stocking density of 10 shrimp tank−1 and fed a commercial shrimp feed (CSF; 35% crude protein) as a control treatment, a feed made entirely of G. cervicornis (GCM), and a mixture of equal parts of the commercial shrimp feed and the Gracilaria meal (MIX) for 30 days. Over the first 2 weeks of the experiment, the survival was high (100%) in all dietary treatments. However, at the termination of the feeding trial survival decreased to 40% in shrimp fed GCM, significantly lower (P<0.05) than survival of shrimp fed the commercial diet control (CSF) or MIX treatments (100%). The highest growth performance was obtained in the CSF or MIX treatment groups. The absolute growth increase in these groups was significantly higher than for shrimp fed GCM. Similarly, the specific growth rates (SGRs) of shrimp given feeds containing CSF (5.11% day−1) and MIX (4.71% day−1) were significantly greater (P<0.05) than that of shrimp fed GCM pellets (0.44% day−1). The feed efficiency ratios (FERs) were 64 for CSF, 54.3 for MIX and 3.3 for GCM. The results obtained in this study indicated the effectiveness of using G. cervicornis as a partial substitute for shrimp feeds. To our knowledge, this is the first time that the concept that macroalgae can partially substitute for the industrial feeds used in shrimp (L. vannamei) farming has been demonstrated.  相似文献   

12.
为研究在养殖过程中降低鱼粉用量的同时保持凡纳滨对虾良好的生长性能和抗逆能力,实验在含10%鱼粉的基础饲料中,分别添加酶解豆粕(PSM) 0%(A)、2.5%(B)、3.5%(C)、4.5%(D)、5.5%(E)制成5组等氮等能饲料,分别投喂初始体质量为(0.45±0.02) g的凡纳滨对虾幼虾8周,检测对虾生长性能及抗胁迫机能。结果显示,8周养殖实验结束后,各实验组对虾的终末体质量为14.65～15.38 g/尾,各组间对虾终末均重、成活率和饲料系数指标均无显著性差异;A组对虾肌肉粗蛋白质含量显著低于其他各实验组;C组、D组和E组对虾肌肉粗脂肪含量显著高于A组;各组间灰分和水分均无显著性差异;D组和E组对虾肝胰腺蛋白酶、淀粉酶、脂肪酶、血清溶菌酶和血清总超氧化物歧化酶活性(T-SOD)均显著高于A组;A组对虾血清丙二醛(MDA)含量显著高于D组和E组。人工急性感染高剂量副溶血性弧菌的胁迫实验中,A组对虾在弧菌感染48和60 h时的累积死亡率均显著高于D组对虾同期的累积死亡率;低剂量副溶血性弧菌人工急性感染后,在凡纳滨对虾鳃组织中检测Toll受体、免疫缺陷(IMD)和溶菌酶3种免疫相关基因的表达量,结果显示,对虾Toll受体、IMD和溶菌酶mRNA表达量最大峰值分别出现在添加酶解豆粕的C组、B组和D组,峰值出现时刻分别为感染后24、42和24 h。研究表明,含10%鱼粉的饲料中添加0%～5.5%酶解豆粕对凡纳滨对虾的生长性能改善效果不显著,酶解豆粕会显著提高凡纳滨对虾肌肉粗蛋白质含量和粗脂肪含量;显著降低对虾血清丙二醛含量;同时也会显著改变凡纳滨对虾对弧菌的抵抗力及其免疫相关基因的时空表达,酶解豆粕添加量达到4.5%时可使养殖的凡纳滨对虾获得最佳的抗弧菌能力。  相似文献   

13.
Total replacement of fishmeal using marine co‐product meals in the diets for white shrimp Litopenaeus vannamei and its effects on growth, feed utilization and muscle HUFA and sterol composition were assessed in a 45‐day feeding trial with juvenile shrimp (0.32 g mean initial weight). Eight dietary treatments were tested: a control diet containing fishmeal (FM), a commercial shrimp diet as external reference and six diets where the FM in the control diet was totally replaced by pen shell scallop viscera (Pinna rugosa), squid viscera (Dosidicus gigas) or whole chub mackerel (Scomber japonicus) meals, produced by two methods: (i) cooking followed by grinding and drying and (ii) grinding followed by drying. Survival in all treatments was above 92%, except in the commercial diet (77%). The growth response, feed utilization and chemical composition of shrimp varied among the treatments and were affected in different ways by the by‐products and the meals preparation process. Growth and feed intake were significantly higher in shrimp fed diets containing cooked‐dried squid and pen shell scallop viscera meals, and whole mackerel meal produced by grinding followed by drying. Muscle fatty acid profiles were improved for human consumption when these ingredients were used, compared with the diets containing FM.  相似文献   

14.
The Pacific white shrimp (Litopenaeus vannamei), as an economically important species, has been reared in low‐salinity water during the last decade. To investigate how juvenile L. vannamei shrimp fed with fructose‐enriched Artemia respond to acute low‐salinity stress, the shrimp were randomly divided into four treatment groups, three groups were fed with Artemia enriched with either 100, 200 and 300 mg L?1 of fructose and a control group fed with Artemia with no enrichment for 10 days. The results showed that the 300 mg L?1 fructose group demonstrated the maximum survival rate and glycogen content. Additionally, the 300 mg L?1 fructose group showed significantly higher Na+/K+‐ATPase activity, total antioxidant capacity, and expression levels of Na+/K+‐ATPase α‐subunit, V‐H ATPase α‐subunit, hexokinase, phosphofructokinase, antioxidants (SOD, CAT, GPX) and Hsp70 mRNA when compared with the control group. Furthermore, after exposure to low salinity, the mRNA levels of phosphofructokinase, V‐H ATPase α‐subunit, GPX, p38, JNK and Rac1 stayed constant in shrimp fed with fructose‐enriched Artemia but changed significantly in the control group. Thus, a diet of fructose‐enriched Artemia can improve the osmoregulation and survival of juvenile L. vannamei shrimp exposed to low salinities.  相似文献   

15.
一株芽孢杆菌PC024的鉴定及其抗WSSV感染效果的研究   总被引：1，自引：1，他引：0  
孙艳  宋晓玲  刘飞  李玉宏  黄倢 《水产学报》2013,37(4):574-583
为了筛选WSSV的防病益生菌株,从健康中国明对虾消化道分离纯化一株芽孢杆菌PC024,经Biolog碳源利用反应、ATB微生物自动鉴定系统、脂肪酸气相色谱分析得出该菌株与坚强芽孢杆菌的生理生化特性最为相似,该菌株为革兰氏阳性菌,有一根端极鞭毛;细胞呈球杆状,有椭圆芽孢;单个菌落呈圆形,中间略微凸起;16S rRNA序列分析表明,该菌株与坚强芽孢杆菌进化地位最接近,同源性均达到100％,综合以上4种方法的鉴定结果,该菌株被鉴定为坚强芽孢杆菌.将已鉴定的PC024菌株粘附于对虾饲料表面投喂给凡纳滨对虾20 d后,进行WSSV肌肉注射感染,测定投喂和感染后对虾血淋巴上清和肝胰腺的免疫相关酶活性,并对对虾肠道总菌数和添加菌PC024进行计数及鉴定.结果表明:添加该菌的实验组对虾相对存活率高,相对保护率达33.7％;投喂含该菌饲料的实验组对虾血清和肝胰腺的相关免疫酶活性较对照组显著提高,对虾肠道总细菌数始终显著高于对照组,并在实验组能够分离得到坚强芽孢杆菌,坚强芽孢杆菌PC024可作为WSSV的防病益生菌株应用于对虾养殖生产.  相似文献   

16.
In three separate experiments, harpaticoid copepods Tisbe monozota (alive and dead) and a microparticulate microbound diet were evaluated as alternatives to live Artemia nauplii as food, beginning at either stage PZ2 or M1, in the larval culture of Litopenaeus vannamei. Larvae were cultured in 2 L round bottom flasks at a density of 150 L− 1 (Experiment 1) and 100 L− 1 ( 3.2 and 3.3) at 28 °C, 35‰ salinity and 12:12 LD photoperiod, and fed 4×/day- 1. Larvae were initially fed a mixture of phytoplankton to stages PZ2 or M1 and then fed either live Artemia, live or dead copepods, or a microparticulate microbound diet. The experiments were terminated and all larvae were harvested when more than 80% of larvae had molted to postlarvae 1 (PL1) within any flask representing any of the treatments. The comparative value of the different diets and feeding regimes was determined by mean survival, mean dry weight and total length of individual larva, and percentage of surviving larvae that were PL1. Trypsin activity of samples of larvae from each treatment was also determined. The microparticulate microbound diet effectively served as a complete substitute for Artemia nauplii when fed beginning at stage M1. When fed at the beginning of the PZ2 stage, survival was comparable to that of larvae fed Artemia, but mean dry weight, mean total length, and percent of surviving larvae that were PL1 generally were significantly less. Responses to the feeding of copepods, whether fed dead or live, as a substitute were generally significantly less than those of larvae fed either the Artemia nauplii or the microparticulate diet. Values of trypsin activity (10− 5 IU/μg- 1 dry weight) corresponded to the relative proportions of the different larval stages within a treatment, with higher activity being characteristic of early stages. Previously demonstrated successful results with another species of crustacean suggest that the microparticulate microbound diet has characteristics that should be effective in the culture of the carnivorous stages of other crustacean and fish larvae that are currently fed live Artemia nauplii.  相似文献   

17.
The present study intended to evaluate the effects of early introduction of inert diet in lipid digestibility and metabolism of sole, while larval feed intake, growth and survival were also monitored. Solea senegalensis larvae were reared on a standard live feed regime (ST) and co-feeding regime with inert diet (Art R). Trials using sole larvae fed with Artemia enriched with two different lipid emulsions, containing glycerol tri [1-14C] oleate (TAG) and L-3-phosphatidylcholine-1,2-di-[1-14C] oleoyl (PL), were performed at 9 and 17 days after hatching (DAH) to study lipid utilization. Co-feeding did not affect sole survival rates (ST 59.1 ± 15.9%; Art R 69.56 ± 9.3%), but was reflected in significantly smaller final weight at 16 DAH (ST 0.71 ± 0.20; Art R 0.48 ± 0.14 mg). Higher feed intake was observed in sole larvae fed on Artemia enriched with labeled PL at 9 DAH but not at 17 DAH. At 17 DAH, the smaller larvae (Art R treatment) ingested proportionally more Artemia in weight percentage, independently of enrichment. At 9 DAH lipid digestibility was equal among treatments and higher than 90%, while at 17 DAH it was higher in ST treatment (around 73%) compared to the Art R group (around 66%). Lipid retention efficiency at 9 DAH was higher in the Art R treatment, reaching values of 50%, while these values almost duplicated at 17 DAH, ranging up to 80% in both treatments without significant differences. These results show that co-feeding of live feed and inert diet from first-feeding in Senegalese sole has a toll in terms of growth and lipid digestibility but does not seem to compromise lipid metabolic utilization.  相似文献   

18.
The aim of this study was to use preselected quality indicators for Litopenaeus vannamei post-larvae and the stable isotopes technique with δ13C and δ15N to determine the influence of bioflocs in shrimp feeding during the nursery phase, between PL1 and PL30. A control treatment (CT) with water renewal was compared to a biofloc treatment (BT) that received organic carbon fertilizations. Different types of commercial feed (Stresspak and Flake-INVE?, PL40-GUABI?), microalgae (Chaetoceros muelleri) and Artemia sp. nauplii were used as food sources. The physical and chemical parameters of water and ammonia were monitored daily, and nitrite, nitrate and alkalinity were measured weekly. Suspended solids and the microorganisms of bioflocs were characterized. At the end of the experiment, fifteen shrimps of each replicate were collected to evaluate nine larvae quality indicators. Isotopic values of 13C and 15N of food sources and shrimp tissues were collected on days 10, 20 and 30, and a Bayesian model of isotopic mixture measured the contributions of these sources to the shrimp biomass. Salinity, alkalinity and nitrite differed significantly between the treatments but were appropriate for post-larvae production. The larvae quality conditions in the CT treatment were ranked as “good,” whereas the BT conditions were considered “excellent” according to the analysis of larval quality parameters. The stable isotopes analysis showed that the PL40 GUABI? feed was the most important food source throughout the experimental period in the CT. In the BT (10th and 20th days), the bioflocs and commercial feeds (Flake-INVE?, PL40-GUABI?) did not present significant variations in their contribution ratios; however, on the 30th day, the contribution of the PL40-GUABI? feed was higher when compared to bioflocs. In general, the commercial feed played a more important role as a food source for Litopenaeus vannamei larvae during the nursery phase, although the consumption of bioflocs led to a better larvae quality.  相似文献   

19.
Due to the economic potential of Hypancistrus zebra in the ornamental fish market and its current classification as an endangered species in its natural occurrence sites, the present study sought to determine a suitable feed management strategy and stocking density to allow for an adequate captivity maintenance of this fish species. Three experiments were conducted as follows: (1) feed preference (artemia Artemia sp., shrimp Litopenaeus vannamei, fish Cynoscion spp. or mussel Perna perna); (2) determination of feeding rate (5% and 10% live weight day?1) and frequency (1, 2 or 3 meals. Day?1); and (3) evaluation of stocking density (0.25, 0.50, 1.00 and 2.00 g/L). Zebra pleco did not present the characteristic buccal scraping behaviour on the feed, commonly seen in other Loricariids. Artemia was the preferred diet followed by fish, shrimp and mussels. The frequency of two daily meals and the feeding rate of 10% live weight day?1 allowed for an improved zootechnical performance. Zebra pleco showed enhanced specific growth rate at the density of 2 g/L. Our results suggest that, to improve the zebra pleco rearing conditions, it should be maintained at a density of 2 g/L, fed two daily meals at a feeding rate of 10% live weight day?1. These findings correspond to useful information for an adequate management of this species and could assist in the supply of healthy specimens to the ornamental fish market as well for the restocking of declining wild populations.  相似文献   

20.
Problems of limited number of dry feeds as supplement or replacement of live feeds have led to poor larval nutrition in many species of fish. Therefore, the suitability of co‐feeding 8‐day‐old African catfish (Clarias gariepinus) posthatch larvae using live feed (Artemia salina) and formulated dry diet containing freshwater atyid shrimp (Caridina nilotica) during weaning was investigated. The experiment ended after 21 days of culture and respective groups compared on the basis of growth performance, survival, feed utilization and nutrient utilization. Larvae co‐fed using 50%Artemia and 50% formulated dry diet resulted in significantly (P < 0.05) better growth performance, food gain ratio (FGR), protein efficiency ratio (PER) and productive protein values (PPV) than other treatments. The lowest growth performance occurred in larvae weaned using 100% formulated and commercial dry diets. Better survival of over 90% was obtained in larvae weaned using 50%Artemia and 50% dry diet, while abrupt weaning using 100% dry diets resulted in lower survival (<75%). These results support a recommendation of co‐feeding C. gariepinus larvae using a formulated dry diet containing C. nilotica and 50% live feed when weaning is performed after 8 days posthatching period.  相似文献   

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