Acclimation of Litopenaeus vannamei Postlarvae to Low Salinity: Influence of Age, Salinity Endpoint, and Rate of Salinity Reduction

Abstract.— Inland culture of Liropenaeus vannarnei in low salinity well waters is currently conducted on a small scale in a few areas in the U.S. To successfully rear shrimp in low salinity water, postlarvae (PL) must be transferred from high-salinity larval rearing systems to low-salinity growout conditions. To determine effective transfer methods, a series of experiments were conducted under controlled conditions to evaluate the influence of PL age, rate of acclimation, and salinity endpoint on 48 h survival of shrimp. Three age classes of L. vannurnei PL (10, 15, and 20-d) were acclimated from a salinity of 23 ppt to treatment endpoint salinities of 0, 1, 2, 4, 8, and 12 ppt. Survival of PL₁₀ acclimated to 0, 1, or 2 ppt salinity was significantly lower than survival of PL acclimated to salinities of 4, 8, and 12 ppt. Survival of PL, and PL₂₀ shrimp was only reduced for the 0 ppt salinity treatment, thus indicating a clear effect of age on salinity tolerance. The same age classes of PL were acclimated from 23 ppt to final salinity endpoints of I or 4 ppt at three different rates of salinity reduction: low, 19%/h; medium, 258/h, and high, 478/h. Survival was not significantly influenced by the acclimation rates for any of the three PL age classes. As in the fixed rate experiments, survival of the 10-d-old PL was significantly lower for shrimp acclimated to the 1 ppt endpoint compared to the 4 ppt endpoint. Under the reported conditions, age appears to influence PL tolerance to a salinity end-point. A 10-d-old PL can be acclimated to 4 ppt with good survival, whereas 15- and 20-d-old PL can be acclimated to a salinity of 1 ppt with good survivals.     

放养密度对凡纳滨对虾苗种中间培育效果的影响

通过对养殖场凡纳滨对虾(Litopenaeus vannamei)实际苗种中间培育进行实验(21 d),探究了放养密度(1.50～2.25万尾/m~3)对凡纳滨对虾的生长性能、养殖水体水质以及细菌群落的影响。结果显示,当放养密度为1.50～2.25万尾/m~3时,放养密度的增加会提高凡纳滨对虾的产率、特定生长率、存活率及饵料转化率。实验期间,各养殖池内水体的pH逐渐下降,氨氮(NH_4~+-N)和化学需氧量(COD)浓度均呈逐渐上升趋势,弧菌(Vibrio)浓度则在一定范围内[(0.3～7.5)×10~4 CFU/ml]波动。放养密度的增加会导致养殖水体pH下降,NH4+-N和COD浓度升高,但对水体中的弧菌浓度没有明显影响。实验末期,放养密度较高的养殖池具有较高的细菌生物多样性,变形菌门(Proteobacteria)(56.52%～71.22%)和拟杆菌门(Bacteroidetes)(20.65%～38.23%)为各养殖池内主要细菌门类,而且弧菌属(Vibrio)(2.3%～9.4%)在各养殖池内均为优势菌属。在凡纳滨对虾苗种中间培育过程中,逐日增加换水量对水体pH和COD浓度具有一定的调节能力,但难以控制NH4+-N和亚硝酸氮(NO_2~--N)浓度的升高。     

Density and Water Exchange-Dependent Growth and Survival of Litopenaeus setiferus Postlarvae

This present study was designed to investigate the effects of stocking density and water exchange on the growth rate, survival and performance index of L. setiferus postlarvae under controlled laboratory conditions. The experiment was done with postlarvae (PL10 to PL40) at densities of 50, 150, 250 and 350 shrimp/m² and various different water exchanges rate per day (0, 6, 12 and 18%). The maximum growth rate was obtained for shrimp with 12% water exchange per day at all densities. A reduction of the maximum growth rate was observed in relation to density with the highest values in shrimp stocked in a density of 50 and 150 shrimp/m² (mean value of 0.53 mg/d) and the lowest in shrimp stocked in a density of 350 shrimp/m² (0.24 mg/d). The multiple regression equation obtained to relate performance index (growth rate* survival : PI), shrimp density (X₁) and water exchange (X₂) was: PI = 0.31 + (0.001) X₁+ 0.039 X₂+ 2.28 × 10⁻⁶ X₁²+ (−0.0017) X₂²+ (0.000026)X₁X₂, R ²= 0.78; P > 0.03. According to this equation the optimum shrimp density-water exchange comhination was between 5 to 12% of water exchange at stocking density of between 50 and 150 shrimp/m². Salinity, ammonia-N and nitrite-N increased according to the time spent in tanks without water exchange. With no (0%) water exchange, water quality parameters measured were outside the optimum for L. setiferus postlarvae. The use of optimum density and water exchange in a nursery system for L. setiferus with optimum variables established is proposed.     

凡纳滨对虾(Litopenaeus vannamei)低盐度围隔调控养殖环境微生物研究

在广东省珠海市斗门一个大小为0.3hm2的空白虾池内,设立10个大小为5×5×1.6m(l×b×d)的陆基池塘围隔,对凡纳滨对虾低盐度调控养殖环境微生物进行实验研究,结果低盐度围隔调控养殖系统,水体异养细菌平均为1.33~9.27×104cfu.ml-1,致病性弧菌平均为2.83~7.91×102cfu.ml-1,养殖水体致病性弧菌的数量比异养细菌平均低2个数量级。各围隔水体异养菌在养殖早期都有一个高峰期,中后期低而稳定;围隔异养细菌的数量并未因定期施菌而增高,反而呈下降的趋势。对虾养殖健康的围隔,中后期水体致病性弧菌保持较低的数量,而对虾发病的围隔,致病性弧菌数量高。围隔调控养殖系统,异养细菌的数量相对比较稳定,而致病性弧菌数量呈较大波动。     

The Effect of Low Salinity Water with Different Ionic Composition on the Growth and Survival of Litopenaeus vannamei (Boone, 1931) in Intensive Culture

The effects of four different ionic composition low salinity water (T₁, T₂, T₃, and T₄), on growth and survival of Litopenaeus vannamei marine shrimp juveniles were investigated. Shrimp culture in seawater (T_m) was used as control treatment. The results indicated that there were no significant difference (P < 0.05) in growth, survival, production, and feed conversion ratio (FCR) of L. vannamei juveniles reared in the different treatments, but significant differences (P < 0.05) were observed between each of them when compared with seawater (T_m). After 84 days, culture shrimp grew from 0.02 to 7.58 g in T₁. The lowest growth rate was attained in T₃ (0.57 g/week), in which potassium and calcium ions concentrations were the lowest (0.58 and 28.00 mg/L, respectively). The recorded survival rate (76.35% to 79.55%) is considered well for the 84 days growout period, although it was 7.6% lower than that recorded in the control treatment. Although there were no significant differences (P < 0.05) in growth with respect to the ionic composition of the four treatments, there was a trend of increasing growth in relation with the ionic ratio found in the seawater (T_m). This aspect should be evaluated more closely in future research.     

The Effect of Controlled Soil Sulfur Concentration on Growth and Survival of Litopenaeus vannamei

Abstract.— In a microcosm study, sodium sulfate was mixed with a controlled composition soil to yield sulfur concentrations of 100 to 3,000 mg/kg and the mixture was inundated to a depth of 35 cm with 18-ppt salinity water. One juvenile Litopenaeus vannamei with initial weight averaging 0.3 g was placed in each soil-water microcosm and fed for 96 d. Dissolved oxygen concentration was maintained at approximately 70% air saturation. Calculated interstitial hydrogen sulfide concentration 0.5 cm below the soil-water interface increased with time, reaching maximum values ranging from 57 to 113 mg/L. Interstitial sulfide concentrations 0.5 cm below the soil-water interface increased as a function of soil S. Average weight gain of shrimp ranged from 7.4 to 8.7 g across treatment groups. Differences in shrimp weight gain and survival among treatments were not significant. A higher dissolved oxygen demand due to sulfide oxidation implies greater risk of shrimp mortality if the soil-water boundary is disturbed. Further, this study suggests that shrimp growth is not adversely affected by high soil sulfide concentration provided the sediment surface remains oxidized and that dissolved oxygen concentration in the overlying water is maintained at 70% saturation.     

Survival of Post‐larval Litopenaeus vannamei Following Acclimation to Low Salinity Waters at Different Temperatures

Temperature and salinity are two factors known to influence the growth potential and survival of the Pacific white shrimp, Litopenaeus vannamei, acclimated to low salinity waters. In west Alabama, farmers suspect low water temperatures at stocking, in conjunction with low salinity and suboptimal ionic profiles, might be responsible for reduced survival and production at harvest. To determine the influence of temperature and salinity on post‐larval (PL) L. vannamei, a series of bioassays were conducted at the E.W. Shell Fisheries Research Station in Auburn, Alabama and Claude Peteet Mariculture Center in Gulf Shores, Alabama. PL L. vannamei of ages 11, 13, and 20 (PL₁₁, PL₁₃, and PL₂₀) were acclimated down to salinities of 12, 4, 2, 1, 0.5, and 0.2 ppt at different temperatures ranging from 17.6 to 24.0 C. During the acclimation bioassays survivals were assessed at 24 and 48 h. PL survival of the three age groups examined were significantly reduced at salinities of 1, 0.5, and 0.2 ppt. These results correspond well to those reported at higher temperatures confirming that across the tested temperature range salinity endpoint was the driving factor in determining survival and that suboptimal temperatures had a minimal influence on survival.     

Effects of Potassium, Magnesium and Age on Growth and Survival of Litopenaeus vannamei Post-Larvae Reared in Inland Low Salinity Well Waters in West Alabama

Abstract— The production of Litopenaeus vannamei in inland low‐salinity well water is a growing industry in several regions of the world. The state of Alabama in the southeastern USA is one such region with a large saline aquifer that could be utilized for shrimp culture. However, some farmers are experiencing problems rearing marine shrimp while others are having considerable success. Previous work has correlated low levels of potassium andor magnesium to poor shrimp survival. The problem is further complicated by the fact that the age at acclimation may also influence survival. In our present study, we evaluated the effects of potassium, magnesium, and the age of acclimation on growth and survival of PL at two farms. The first experiment was run in a static system utilizing four replicate tanks per treatment. Fifty PL₁₇ (0.0066 g) that had been acclimated to 4 ppt seawater were stocked into each tank and the following treatments evaluated: low salinity well water (LSWW) without mineral supplements, LSWW with KCl, LSWW with MgCl₂, and LSWW with KCl and MgCl, added to the water. Shrimp were harvested, counted and weighed after 4 wk. Survival was significantly higher in treatments receiving mineral supplements whereas biomass was only higher in the two treatments with potassium supplements. The second experiment was set up initially as a static system filled with 8.5‐ppt reconstituted sea water that was then converted to a flow‐through system using LSWW. This experiment evaluated the effect of PL age at acclimation on survival and growth at four different ages (PL₁₅, PL₁₉, PL₂₃, and PL₂₇). All tanks were stocked with 50 PL₁₃L. vannarnei. Two days after stocking, and then at 4‐d intervals, a series of four tanks were converted to flow through (rate of 40 Lhr) using LSWW. After acclimation, water flow was maintained in all tanks until 28 d after stocking when tanks were harvested and surviving shrimp were counted and weighed. Survival and growth increased with PL age when shrimp were acclimated to inland low salinity well water.     

不同盐度对生物絮团、对虾生长以及酶活性的影响

在不同盐度条件下进行凡纳滨对虾的生物絮团养殖试验,研究盐度对生物絮团养殖水质和对虾生长及其酶活性的影响。试验设5个盐度梯度(10、15、20、25、30),生物絮团初始量为20 mL/L,对虾密度为500尾/m^3,试验周期30 d。试验结果显示,15盐度组与20盐度组的对虾体质量增长率最大,达70.73%,10盐度组的体质量增长率最小,达50.24%。盐度越高生物絮团生长越快,30盐度组17 d生物絮团沉降量达200 mL/L,之后逐渐降至43 mL/L,其他组呈相同变化趋势。试验过程中水体总碱度与pH持续降低,但不同组间差异不显著(P>0.05)。盐度越高氨氮累积越快,30盐度组在第6 d达到最大质量浓度8.62 mg/L,之后降至0 mg/L,其他组呈相同趋势变化。盐度越低亚硝态氮累积越快,10盐度组在第6 d达到最大质量浓度9.18 mg/L,之后降至0 mg/L,其他组呈相同趋势变化。硝态氮在不同盐度中呈前期上升的趋势,第16 d之后开始缓慢下降。15盐度组的淀粉酶活性显著高于其他组(P<0.05),其他各组之间无显著差异(P>0.05)。脂肪酶在25盐度组活性最高,盐度升高或者降低酶活性均降低。在10、15、20盐度组中,超氧化物歧化酶、碱性磷酸酶、酸性磷酸酶活性均维持在较高水平,在相同盐度下,肌肉酶活性低于肝胰脏。     

Investigation of the Effects of Salinity and Dietary Protein Level on Growth and Survival of Pacific White Shrimp, Litopenaeus vannamei

It is presumed that in hypo‐ and hypersaline environments, shrimp’s requirements for some specific nutrients, such as protein, may differ from those known in the marine habitat; however, few investigations have been conducted in this area of study. In the present investigation, the effects of salinity and dietary protein level on the biological performance, tissue protein, and water content of Pacific white shrimp, Litopenaeus vannamei, were evaluated. In a 3 × 4 factorial experiment, juvenile shrimp with an average initial weight of 0.36 ± 0.02 g were exposed for 32 d to salinities of 2, 35, and 50 ppt and fed experimental diets with crude protein contents of 25, 30, 35, and 40%. A significant effect of salinity on growth of shrimp was detected, with the growth responses (final weight, weight gain) ranked in the order 2 ppt (3.87, 3.50 g) > 35 ppt (3.40, 3.04 g) > 50 ppt (2.84, 2.47 g). No effects of dietary protein level or an interaction between salinity and protein on growth of shrimp were observed under the experimental conditions of this study. Percent survival of shrimp fed the highest protein content (40%, survival of 74%) was, however, significantly lower than those of shrimp fed the other feeds (25, 30 and 35% protein, survival of 99, 91, and 94%, respectively), a result likely associated with the concentration of total ammonia nitrogen, which increased significantly at increasing protein levels. Final water content of whole shrimp was significantly lower in animals exposed to 50 ppt (70.8%) than in shrimp held at 2 (73.7%) and 35 ppt (72.3%). No effect of salinity, protein, or their interaction was observed on the protein content of whole shrimp. The results of the present study are in agreement with reports of superior and inferior growth of L. vannamei reared in hypo‐ and hypersaline environments, respectively, as compared to what is generally observed in seawater.     

Studies of the Thermal and Haline Influences on Growth and Survival of Litopenaeus vannamei and Litopenaeus setiferus

A series of experiments were conducted to examine the effects of salinity (1–48 g/L) on the biological performance, as evaluated by growth and survival, of the Pacific white shrimp, Litopenaeus vannamei, and the Atlantic white shrimp, Litopenaeus setiferus, reared at temperatures of 20, 24 or 28 C. Poor growth and survival of L. vannamei was observed after 21–28 d of culture at low salinity (2 and 4 g/L) at 20 C. Raising salinity to 8 and up to 32 g/L significantly increased survival at this temperature, indicating that avoiding low temperatures is critical for survival of this species when reared at low salinity. A major improvement in the growth rate of L. vannamei was observed at 24 C, but it still was sub‐optimal compared to growth observed at 28 C. Irrespective of salinity, high survival rates were observed at both 24 and 28 C, but variable growth rates were recorded. Contrary to L. vannamei, the Atlantic white shrimp, L. setiferus, which was reared for 28 d at 24 C only, had better growth performance at 8 g/L compared to 2, 16 and 32 g/L. Under equal experimental conditions, L. setiferus had considerably lower weight gain and survival than L. vannamei.     

盐度对毛蚶稚贝生长和存活的影响

试验结果表明,毛蚶为广盐性滩涂贝类,盐度对其有着显著的影响。其适宜盐度17~37,最适盐度23~33。并且低盐条件较高盐条件有着更高的生长率,但存活率低于高盐环境。     

Effects of Dietary Short-chain Fructooligosaccharides on Intestinal Microflora, Survival, and Growth Performance of Juvenile White Shrimp, Litopenaeus vannamei

Abstract.— Five groups of juvenile white shrimp, Litopenaeus vannamei , in triplicate were separately fed a compound diet with additional short-chain fructooligosaccharides (ScFOS, Profeed^® 95%) 0, 0.4, 0.8, 1.2, or 1.6 g/kg dried diet for 8 wk to investigate the effects of ScFOS on the intestinal microflora, survival, and growth performance of the shrimp. The juvenile shrimp with around 0.17 g of initial body weight were divided into 30 per tank and reared in a standard water recirculation system at 28 C. The shrimp were fed five times a day. At the end of experiment, the shrimp were weighed and their intestinal samples were analyzed for the amounts of Vibrio parahaemolyticus, Aeromonas hydrophila, Lactobacillus sp. , and Streptococcus faecalis using selective agar. The results showed that the shrimps' weight gain and specific growth rate increased with the increment of dietary ScFOS, while their feed conversion ratio decreased. The result was the best when an additional ScFOS 0.4 g/kg dried diet was used.     

凡纳滨对虾家系幼虾淡化和养殖阶段存活性状遗传参数估计

准确估计育种目标性状的遗传参数,评估其改良潜力,是制定育种方案、进行选择育种工作的重要前提条件。本研究对100个凡纳滨对虾(Litopenaeus vannamei)家系15000尾仔虾个体进行淡化和低盐养殖实验,分析了2个阶段家系间存活率的差异,并进一步估计存活性状的遗传力。结果显示,2个阶段存活率范围分别为19.3%~100.00%和11.86%~99.22%,平均存活率分别为66.7%和67.5%。家系幼虾期总体存活率为6.67%~90.67%,平均存活率为46.91%。统计分析显示,2个阶段家系间存活率差异极显著(P0.01),存活率的相关系数为0.61(P0.01),呈中度正相关(0.3r0.8)。利用加性效应(A)和加性+共同环境效应(A+C)模型分别估计了淡化、低盐度养殖以及合并2个阶段存活性状转换后的遗传力。基于A模型,淡化阶段、养殖阶段和合并2个阶段存活性状转换后的遗传力分别为0.46、0.41和0.53,与0相比,估计值均达到极显著水平(z2.58);基于A+C模型,3个阶段遗传力转换后估计值分别为0.06、0.05和0.07,与0相比,估计值均未达到显著水平(z1.96)。基于A模型和A+C模型,获得的2个阶段间家系存活性状育种值的相关系数分别为0.41±0.09和0.48±0.09。由于半同胞家系比例仅为47%,家系单独在网箱中测试,家系遗传效应与共同环境效应部分混淆,因此,基于A模型获得的遗传力估计值偏高,基于A+C模型获得的遗传力估计值偏低。本研究结果表明,通过多代选择育种,可以改良凡纳滨对虾幼虾淡化和低盐度养殖存活性能。     

Effect of Dietary Astaxanthin on Growth,Survival, and Stress Tolerance of Postlarval Shrimp,Litopenaeus vannamei

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.     

饲料中添加凹土对凡纳滨对虾存活和生长的影响

研究了饲料中添加凹土(0.0%、0.5%、1.0%、2.0%、4.0%和8.0%)对凡纳滨对虾(1.04～1.06 g)存活和生长的影响.实验在淮海工学院江苏省海洋生物技术重点建设实验室进行,凡纳滨对虾(Litopenaeus vannamei)幼虾购白海南某育苗场;实验采用单因子6水平设计,每个水族箱放养10尾对虾,每个水平设3个重复.实验前停食24 h,称其初始体重.日投饵2次,过量投饵;投饵2.5 h后从每个水族箱收集残饵、粪便和虾壳.实验周期30 d.所得数据用单因素方差分析和Turkey's多重比较进行处理.结果表明,饲料中添加凹土显著地影响对虾的特定生长率,而对存活率、摄食量、饲料系数和吸收效率的影响不显著;在2.0%凹土水平,凡纳滨对虾的特定生长率显著高于0.0%凹土水平,但与其它处理差异不显著;总的看来,2.0%凹土添加组对虾的饲料系数低于其它处理,而摄食量高于其它处理.     

饲料添加益生菌对多病原阳性的凡纳滨对虾生长与存活的影响

采用假交替单胞菌(Pseudoalteromonas sp.) KL-3 2010和微小杆菌(Exiguobacterium sp.) KL-C2 2014作为益生菌,进行凡纳滨对虾(Litopenaeus vannamei)投喂实验,研究上述菌株对带毒对虾的生长与存活的影响。假交替单胞菌KL-3 2010对致急性肝胰腺坏死副溶血弧菌(Vibrio parahemolyticus) (VPAHPND 20130629002S01)有拮抗作用和胞外蛋白酶活性,微小杆菌KL-C2 2014有胞外蛋白酶活性。待试对虾经检测为白斑综合征病毒(WSSV)、致急性肝胰腺坏死病副溶血弧菌(VPAHPND)和虾肝肠胞虫(EHP)弱阳性。经过为期60 d的养殖实验,结果显示,与投喂普通颗粒饲料的对照组相比,投喂假交替单胞菌KL-3 2010的对虾存活率提高了213%±43% (P<0.01);投喂微小杆菌KL-C2 2014的对虾平均生长率提高了105.5%±28.1% (P<0.05);交替投喂2株菌的对虾存活率提高了184%±52% (P<0.05),平均生长率提高了70.6%±32.8%。肠道可培养优势菌研究表明,2株益生菌的投喂显著影响了对虾肠道优势菌群的种类。本研究为带毒虾苗的养殖提供一种有效的病害防控和促生长的手段。     

饲料中添加凹土对凡纳滨对虾存活和生长的影响

研究了饲料中添加凹土（０．０％、０．５％、１．０％、２．０％、４．０％和８．０％）对凡纳滨对虾（１．０４～１．０６ｇ）存活和生长的影响。实验在淮海工学院江苏省海洋生物技术重点建设实验室进行,凡纳滨对虾（Ｌｉｔｏｐｅｎａｅｕｓｖａｎｎａｍｅｉ）幼虾购自海南某育苗场;实验采用单因子６水平设计,每个水族箱放养１０尾对虾,每个水平设３个重复。实验前停食２４ｈ,称其初始体重。日投饵２次,过量投饵;投饵２．５ｈ后从每个水族箱收集残饵、粪便和虾壳。实验周期３０ｄ。所得数据用单因素方差分析和Ｔｕｒｋｅｙ′ｓ多重比较进行处理。结果表明,饲料中添加凹土显著地影响对虾的特定生长率,而对存活率、摄食量、饲料系数和吸收效率的影响不显著;在２．０％凹土水平,凡纳滨对虾的特定生长率显著高于０．０％凹土水平,但与其它处理差异不显著;总的看来,２．０％凹土添加组对虾的饲料系数低于其它处理,而摄食量高于其它处理。     

盐化幅度、速度及方式对凡纳滨对虾仔虾生长和存活率的影响

本研究测定了盐化幅度(3/d、6/d、9/d、12/d和15/d)、盐化速度(1、3、6、12和18 h/次)和盐化方式(前期盐化、中期盐化、后期盐化和间隔盐化)与凡纳滨对虾(Litopenaeus vannamei)仔虾生长发育、活力和存活率的关系。研究结果显示,不同盐化幅度、盐化速度和盐化方式均显著影响盐化标粗过程中仔虾的生长发育、活力和存活率(P<0.05)。综合考虑生长性能、苗种活力和存活率等因素,最适盐化幅度为3~6/d,在该盐化幅度范围内,仔虾存活率可达74.07%~78.83%;盐化幅度超过9/d时,仔虾存活率显著下降(P<0.05),其中,盐化幅度达到15/d时,存活率仅为43.37%。过快的盐化速度导致存活率和活力显著下降,盐化速度>1 h/次时,仔虾死亡率接近50%;随着盐化速度的放缓,仔虾生长速度加快,盐化速度为6~18 h/次时,生长速度维持稳定,日增重量为1.48~1.51 mg。在盐化方式方面,后期盐化和间隔盐化时,苗种的质量和存活率优于前期盐化和中期盐化,仔虾活力表现为间隔盐化>后期盐化>中期盐化>前期盐化。综合考虑,仔虾的最适盐化幅度为3~6/d,最佳盐化速度为6~12 h/次,后期盐化和间隔盐化更有助于仔虾保持较好活力和较高存活率。本研究通过探讨凡纳滨对虾苗种盐化标粗的最适盐化幅度、盐化速度和盐化方式,丰富了凡纳滨对虾高盐环境抗逆性研究,为凡纳滨对虾苗种的盐化标粗生产实践提供了理论支持。