匙吻鲟亲鱼培育及规模化人工繁殖技术

采用分阶段培育方式培育匙吻鲟亲鱼,后备亲鱼（5～6龄）在水库及坝下池塘培育,催产用亲鱼在流水池中强化培育,各阶段通过控制水流速度、水温、水质和饵料条件,满足其性腺发育需求。2008年至2010年共培育后备亲鱼1017尾,性腺发育成熟亲鱼110组,并逐尾包埋电子标签,建立不同年龄段亲鱼种源库。采用B超结合体形观察判断早期性别,结合挖卵检查准确判断亲鱼的成熟度,依据成熟度确定催产剂量,并通过控制水温、水流速度、挤卵排精时间等催产和孵化条件,人工繁殖的催产率、受精率和孵化率显著提高,年均分别达到95%、95%、78.3%,三年共孵化匙吻鲟鱼苗1246.6万尾。实现了匙吻鲟规模化人工繁殖的目标。     

Early Growth and Survival of Larval Alligator Gar,Atractosteus spatula,Reared on Artificial Floating Feed with or without a Live Artemia spp. Supplement

Alligator gar, Atractosteus spatula, are a new aquaculture species with many aspects about rearing unknown. Alligator gar are cannibalistic during their larval stage and methods to minimize cannibalism should be developed to increase overall survival. Growth and survival were determined for larvae fed pelleted floating food only or fed pelleted floating food supplemented with live Artemia spp. nauplii for the first 7 d of exogenous feeding (5 d after hatching [d.a.h.] to 12 d.a.h.). Total length, weight, condition, and specific growth rate (SGR) was determined at 12 and 20 d.a.h. Fish supplemented with Artemia were larger by 12 d.a.h. and continued to be at 20 d.a.h. than fish fed only floating food. SGR was higher at both 12 and 20 d.a.h. for fish that received the Artemia supplement. Survival was higher for fish supplemented with Artemia (71%) than for the floating food only treatment (43%). Cannibalism was the primary cause of mortalities and was higher in fish fed floating food only (44%) compared to Artemia supplemented fish (19%). Artemia may elicit a stronger feeding response and improve acceptance of pelleted floating foods. Results suggest an improved feeding regime compared to previous feeding regimes used in rearing larval alligator gar.     

Stimulatory effect of thyroid hormones improves larval development and reproductive performance in alligator gar (Atractosteus spatula) and spotted gar (Lepisosteus oculatus)

Development of alligator gar (Atractosteus spatula) and spotted gar (Lepisosteus oculatus) larvae was evaluated after exposure of embryos to thyroid hormones (TH) by two different methods of administration. For the first method, alligator gar embryos were placed in a water bath with triiodothyronine (T₃; 1 ppm for 2 h), and control treatment embryos were placed in a water bath without T₃. For the second method, spotted gar adult males and females were injected with different TH during induced spawning: a group was injected with T₃ [20 mg kg^?1 body weight (BW)], a second group with thyroxine (T₄; 20 mg kg^?1 BW), a third group with thyroid‐stimulating hormone (TSH; 4 IU kg^?1BW) and a control group with dimethyl sulfoxide. Both methods resulted in increases in the concentrations of T₃ and T₄ in embryos of both species. An increase in the alkaline enzymatic activity of TH‐treated larvae was observed as well as an increase in the RNA:DNA, RNA:Dry weight and DNA:Dry weight ratios at hatching. Some positive effects of TH application were: a significant increase in the hatching rate of spotted gar larvae from TH‐injected parents and a higher percentage of successful spawns. Evenness of larval sizes and a higher survival rate were observed in alligator gar larvae. Snout development was accelerated by TH treatment in both species.     

丁鱼岁池套养匙吻鲟技术模式初探

为探索丁[鱼岁]池套养匙吻鲟的技术模式，选择养殖环境条件较好的4亩养鱼池进行套养试验。池内共投放体长3cm左右的丁[鱼岁]夏花鱼种2万尾，体长7～12cm的匙吻鲟夏花鱼种100尾，经4个月左右的饲养，收获丁[鱼岁]商品鱼1350kg，匙吻鲟商品鱼74．5kg，总支出11600元，销售总收入22625元，总利润11025元，亩利润2756元，投入产出比1：1．95，出池产量、育成规格、养殖经济效益均相当理想。     

微生态制剂对匙吻鲟生长性能、体组成及血清生化指标的影响

试验匙吻鲟幼鱼400尾,均经过膨化饲料驯食,并完全适应网箱的养殖环境。试验分处理组和对照组,匙吻鲟幼鱼各200尾,对照组体重(56.28±15.43)g,处理组体重(55.77±16.82)g。处理组在基础日粮中拌和微生态制剂A(7.47×107cfu/g)和B(2.23×108cfu/g)各5 m L/kg,试验时间80 d,评估微生态制剂对匙吻鲟生长性能、体组成及血清生化指标的影响。结果表明:处理组匙吻鲟的末重[(296.89±86.17)g]显著高于对照组[(275.03±85.14)g](P0.05),躯干长[(24.55±2.22)cm]和全长[(47.35±3.54)cm]极显著高于对照组[(23.55±2.33)cm,(46.16±3.87)cm](P0.01),饲料系数(2.02)低于对照组(2.11),相对增重率和特定生长率较对照组分别提高了11.24%和5.56%;脏体比、肝体比、肠长比等生物学性状和肌肉及肝脏的体组成与对照组均无显著差异(P0.05);处理组血清谷丙转氨酶[(200.14±35.85)U/m L]和γ谷氨酰转肽酶[(0.76±0.36)U/m L]活性显著低于对照组[(253.80±23.72)U/m L,(1.33±0.32)U/m L](P0.05),谷草转氨酶、总蛋白、白蛋白、球蛋白、白蛋白/球蛋白、葡萄糖、总胆固醇、甘油三酯、高密度脂蛋白和低密度脂蛋白的活性或含量与对照组均无显著差异(P0.05)。研究表明,饲料中添加微生态制剂能够提高匙吻鲟的生长性能和饲料利用率,改善其健康状况。     

匙吻鲟小瓜虫病的观察与防治

匙吻鲟Ｐｏｌｙｏｄｏｎｓｐａｔｈｕｌａ隶属于匙吻鲟科Ｐｏｌｙｏｄｏｎ ｔｉｄａｅ,主要分布于美洲北部,我国从1990年开始从美国引进。通过10多年的引进与推广,在受精卵孵化、仔鱼培育、苗种培育等方面取得一定的进展,不少地方已开展了人工养殖。但在匙吻鲟苗种培育过程中,有些地方发生了小瓜虫病,致使苗种大量死亡,造成严重损失。现将我们1998年和2000年进行的小瓜虫病的观察与防治总结如下。1　基本情况匙吻鲟苗种系从美国引进受精卵,在实验室内经孵化、仔幼鱼培育而成。养殖容器为长方形(90ｃｍ×50ｃｍ×70ｃｍ)和圆形(直径135ｃ…     

Growth, Condition, and Size Distribution of Paddlefish, Polyodon spathula, Juveniles Reared in Ponds at Three Densities

Abstract.— A study was conducted to determine the effect of increasing density on growth and size distribution of paddlefish, Polyodon spathula, juveniles reared in ponds. Feed‐trained paddlefish of mean weight (±SE) 25.8 ± 1.1 g were randomly stocked into nine 0.02‐ha ponds at 12,355, 18,533, and 24,710 paddlefish/ha, three replications per treatment. The fish were fed daily in excess of what they would eat for 97 d, beginning with a floating trout diet containing 45% protein and 16% lipid and then transferring to a floating catfish diet containing 32% protein and 4.5% lipid. Survival at harvest was not significantly different (P > 0.05) among treatments and averaged 90%. Mean final weights (±SD) for the low‐, middle‐, and high‐density treatments were 205.2 ± 54.1, 174.8 ± 53.2, and 178.6 ± 51.4 g, respectively. Best‐fit distributions centered on these means were lognormal. The low‐density distribution was significantly different (P < 0.05) from the two higher densities, which were not significantly different from each other (P > 0.05). Paddlefish weight at the minimum target length of 35 cm was estimated to be 100 g by regression analysis. The probability of paddlefish reaching or exceeding 100 g was 90% for the low‐density treatment. For the two higher densities, probabilities were 79 and 78%, respectively. Mean Fulton’s condition factors (FCFs) (±SD) were 250 ± 19, 242 ± 4, and 256 ± 37 for the low‐, middle‐, and high‐density treatments, respectively. The FCF for the middle‐density treatment was significantly lower than for the low‐ and high‐density treatments (P < 0.05), which were not significantly different from each other (P > 0.05). CV, feed conversion ratio, and relative growth were not significantly different (P > 0.05) among treatments and averaged 0.43, 1.50, and 5.45, respectively. Monoculture of paddlefish juveniles in ponds results in a hierarchic size structure when density is at least greater than 12,355 paddlefish/ha. The effect is enhanced with increasing density but becomes asymptotic as density approaches 18,533 paddlefish/ha. Feeding in excess does not ameliorate the effect.     

饲料蛋白水平对匙吻鲟幼鱼肌肉营养成分及消化酶活力的影响

配制蛋白水平34.16%、36.53%、39.10%和41.08%的4种等能半精制饲料,在水温28～32℃条件下,饲喂体质量(19.91±3.73)g的匙吻鲟45d,研究饲料蛋白水平对匙吻鲟肌肉营养成分和消化酶(酸性蛋白酶、碱性蛋白酶、α-淀粉酶和脂肪酶)活性的影响。结果显示,41.08%组体质量显著高于36.53%组,其余各组体质量差异不显著;肌肉粗蛋白含量随着饲料蛋白水平的增加而增加,各组肌肉水分、粗脂肪和粗灰分含量差异不显著;酸性蛋白酶和肝胰脏碱性蛋白酶活力随饲料蛋白水平的增加而增加,而肠道碱性蛋白酶活力随饲料蛋白水平的增加而降低;消化道α-淀粉酶活力随饲料蛋白水平的增加而降低,而肝胰脏α-淀粉酶活力表现出相反的趋势;饲料蛋白水平对消化道和肝胰脏脂肪酶活力影响不显著,各组脂肪酶活力差异不显著。试验结果表明,饲料蛋白水平对匙吻鲟肌肉粗蛋白含量、酸性蛋白酶、碱性蛋白酶和α-淀粉酶都会产生显著影响;饲料蛋白水平为39.10%比较适宜。     

匙吻鲟人工育苗和网箱高产饲养试验

为了开发匙吻鲟这一新的养殖品种,优化杭州市淡水养殖的品种结构,提高大水面的综合养殖效益,杭州市水产技术推广站等单位于2003～2004年在杭州市萧山海润养殖有限公司和淳安县千岛湖实施了浙江省海洋与渔业局科研项目——《匙吻鲟孵化驯养与大水面增养殖技术研究》。     

匙吻鲟稚鱼摄食节律与饥饿对其体脂肪酸组成的影响

在水温20~27℃下,将体质量2~3g的匙吻鲟稚鱼饲养在55cm×45cm×35cm的塑料箱(约86L)内,投喂天然浮游动物,采用肠充塞度和饱满指数法,研究其摄食节律和饥饿72h后全鱼脂肪酸组成的变化。结果显示,匙吻鲟稚鱼摄食的最高峰在17:00,次高峰在5:00,摄食低谷在23:00,胃内食物6h排空,而肠在36h仍未排空;经过0~72h饥饿后,匙吻鲟全鱼饱和脂肪酸和单不饱和脂肪酸含量随饥饿时间的延长而显著下降(P0.05),而多不饱和脂肪酸水平和二十碳五烯酸比例显著上升(P0.05),二十二碳六烯酸比例升高,但差异不显著(P0.05)。结果表明,匙吻鲟稚鱼为晨昏摄食型;饥饿期间主要消耗饱和脂肪酸和单不饱和脂肪酸供能,而多保留多不饱和脂肪酸,尤其是选择性保留二十碳五烯酸和二十二碳六烯酸。     

Comparisons of Two By-Products and a Prepared Diet as Organic Fertilizers on Growth and Survival of Larval Paddlefish,Polyodon spathula,in Earthen Ponds

Two agro-industrial by-products, rice bran (RB) and distillers dried solubles (DS), and a prepared diet (PD) were evaluated as organic fertilizers for the production of juvenile paddlefish in nine 0.02-ha earthen ponds over a 40-day culture period. Paddlefish yield from ponds fertilized with RB (209 kg/ha) was significantly greater (P≤0.05) than that from ponds fertilized with DS (129 kg/ha), but it was not significantly greater than yields from ponds fertilized with PD (258 kg/ha). Fish survival from ponds fertilized with PD (79%) was significantly higher than from ponds fertilized with RB (55%) or DS (50%). There was no significant difference in survival between ponds fertilized with RB and DS. Secchi disk visibilities in ponds fertilized with RB were significantly lower than in ponds fertilized with DS and PD. Relatively low Secchi disk visibilities in RB-fertilized ponds were because of a brown stain or coloration which reduced sunlight penetrationa and growth of filamentous algai, not observed in Ds- or PD-fertilized ponds. Larvae congregated in areas where PD was being applied, whcih suggested direct feeding on PD. Paddlefish did not respond when RB and DS were applied to ponds. Cost per juvenile paddlefish raised in ponds fertilized with RB was $0.004, cheaper than $0.011 for fish raised in ponds fertilized with PD or DS. Rice bran is the recommended agro-industrial by-product to raise juvenile paddlefish greater than 120 mm total length based on improved fish yields, pond water quality, and lower cost per fish. The prepared diet may be used not only as an organic fertilizer, but also as a supplemental feed.     

非离子态氨及亚硝酸盐对欧洲鳗鲡的急性毒性试验

１９９７年６～８月,通过人工控制ＮＨ３－Ｎ及ＮＯ２－－Ｎ的浓度,对欧洲鳗鲡进行急性毒性试验的结果表明：非离子态氨对欧洲鳗鲡２４、４８、９６ｈ的半致死浓度分别为４．２６、３．２７、２．１９ｍｇ／Ｌ,安全浓度为０．２１９ｍｇ／Ｌ;亚硝酸盐对欧洲鳗鲡２４、４８、９６ｈ的半致死浓度分别为１００．０、８４．１、２６．６ｍｇ／Ｌ,安全浓度为２．６６ｍｇ／Ｌ。     

Food Selection by Larval Paddlefish Polyodon spathula Supplied with Rice Bran to Promote Production of Live Foods, with Prepared Diets, or with their Combination in Earthen Ponds

Food selection of larval paddlefish Polyodon spathula was evaluated by gut analysis in nine 0.02-ha ponds either fertilized with rice bran (RB) to promote zooplankton production, supplied with prepared diets (PD), or with a combination of rice bran and prepared diet (CB). After 40 d, mean fish yields in RB and CB ponds were significantly higher ( P < 0.05) than fish yield in PD ponds, but there was no significant difference ( P > 0.05) in survival among treatments. Cladocerans were the main Live food items selected by paddlefish in RB and CB ponds. Chironomid larvae were the main food items selected by paddlefish in PD ponds. Less than 10% of the food found in paddlefish guts was prepared diets in PD and CB ponds. Prepared diets apparently were not as available to the fish or were not as preferred by the fish as Live foods. Levels of un-ionized ammonia were significantly greater in CB and PD ponds than that in RB ponds. Decomposition of uneaten high-protein diets in PD and CB ponds probably led to production of ammonia. Elevated un-ionized ammonia levels during week 5 caused abnormal swimming behavior and some paddlefish mortalities in PD and CB ponds. Based upon these results, use of RB or other organic fertilizers to promote zooplankton production is recommended over direct feeding or a combination of fertilization and feeding for larval paddlefish in earthen ponds.     

Alligator gar (Atractosteus spatula,Lacépède 1803) vitellogenin: purification,characterization and establishment of an enzyme‐linked immunosorbent assay

Alligator gar (Atractosteus spatula) is a non‐teleost bony fish distributed in North America. Gar populations have drastically declined as a consequence of habitat deterioration and the lack of regulation for their capture. Control of reproduction is critical for recovering their natural populations. The impossibility to distinguish genders and the determination of sexual maturity have hindered their successful reproduction. This research was aimed at developing an enzyme‐linked immunosorbent assay (ELISA) for the quantitative estimation of vitellogenin (VTG), a female‐specific protein. Plasmatic VTG from 17β‐estradiol (E2)‐induced juveniles and ovary vitellin from adult females were purified and characterized. Polyclonal antibodies against both proteins were produced to develop an ELISA. The immunoassay was validated by quality tests such as sensitivity, parallelism, recovery, reproducibility and specificity. Vitellogenin was determined in different tissues (plasma, mucus, liver and gills) of alligator gar. Vitellogenin and E2 concentrations in female breeders were found to be higher in November, before the spring spawning season. This approach represents a quick, reliable and non‐invasive practical alternative to distinguish genders and evaluate gonad maturation.     

Acute Toxicity of Ammonia and Nitrite to Painted River Prawn,Macrobrachium carcinus,Larvae

This study evaluated the toxicity of ammonia and nitrite to different larval stages of Macrobrachium carcinus. Three replicated groups of larvae in the zoea stages II, V, and VIII (hence named Z₂, Z_5, and Z₈, respectively) were exposed separately to five ammonia (5, 10, 20, 40, and 80 mg total ammonia nitrogen [TAN]/L) and six nitrite concentrations (5, 10, 20, 40, 80, and 160 mg NO₂‐N/L), plus a control treatment with no addition of ammonia and nitrite, at a salinity of 20 g/L. The ammonia LC₅₀ values at 96 h for Z₂, Z₅, and Z₈ were 8.34, 13.84, and 15.03 mg TAN/L (0.50, 0.71, and 0.92 mg NH₃‐N/L), respectively, and the nitrite LC₅₀ values at 96 h for Z₂, Z₅, and Z₈ were 3.28, 9.73, and 34.00 mg NO₂‐N/L, respectively. The estimated LC₅₀ values for NO₂‐N were lower than those for TAN in most of the stages evaluated. This observation suggests that M. carcinus larvae are more tolerant to ammonia, except at Z₈, in which larvae had a higher tolerance to nitrite. Based on the lethal concentrations at 96 h, it may be concluded that the tolerance of M. carcinus to ammonia and nitrite increases with larval development. Safe levels were estimated to be 0.834 mg TAN/L (0.05 mg NH₃‐N/L) and 0.328 mg NO₂‐N/L; therefore, efforts should be made to maintain lower concentrations of these compounds throughout the larval rearing of M. carcinus.     

非离子氨对文昌鱼的急性毒性影响

日换水一次的条件下,研究了25℃恒温时非离子氨对90日龄文昌鱼幼鱼[(24.46±0.12)mm,(0.044±0.008)g]和成体[(39.24±1.36)mm,(0.093±0.012)g]的急性毒性。试验结果显示,非离子氨对文昌鱼幼体及成体的24、48、72、96h的半致死质量浓度分别为0.560、0.457、0.344、0.318mg/L和0.770、0.682、0.544、0.499mg/L;非离子氨对文昌鱼幼体及成体的安全质量浓度分别为0.032、0.050mg/L。文昌鱼对非离子氨具有较强的耐受性,成体的耐受性明显强于幼体。     

Ionic composition and osmolality of paddlefish (Polyodon spathula, Acipenseriformes) seminal fluid

Changes in ionic composition as Na⁺,K⁺, Ca²⁺ and Mg²⁺, osmolality inseminal fluid, percentage of motile spermatozoaand velocity were investigated in response toCPP and different dosage of LHRHa. The lowestvelocity of sperm was observed after use CPPtreatment. The velocity of spermatozoa,significant main effect of the treatment(P < 0.0001) and the time of sperm collection(P < 0.0104) were evaluated. The osmolality ofseminal fluid was different betweenexperimental groups of LHRHa (48.0–62.7mOsmol.kg^–1) and CPP (33.0–46.3mOsmol.kg^–1) treatments. The osmolalitywas significantly higher on the first day andone-half, then declined on day three, rangingfrom 33.0 to 62.7 mOsmol.kg^–1. Analysisof variance showed significant main effects ofthe treatment (P < 0.0001) and the time ofsperm collection (P < 0.0002) on the osmolalityof seminal fluid. The level of Na⁺ andK⁺ ion was different between experimentalgroups of LHRHa and CPP treatment. The highestconcentration of 11.11 mmol.l^–1 wasobserved at Na⁺ ion. Then theconcentrations declined on the level 1.56, 0.52and 0.36 mmol.l^–1 for K⁺, Ca²⁺and Mg²⁺ ions, respectively. There werehighly positive correlations between osmolalityof seminal fluid and dosage of LHRHa treatment(r = 0.84), velocity of spermatozoa andosmolality of seminal fluid (r = 0.57) andosmolality of seminal fluid and Na⁺concentration at seminal fluid (r = 0.70).Injection with LHRHa increased quality of spermas velocity of sperm, level of Na⁺,K⁺ and osmolality at seminal fluidcompared to CPP treatments.