[12]水环境 ( Mg2++Ca2+ )/(Na++K+ ) 比值对凡纳滨对虾幼虾生长和能量收支的影响

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水环境Mg2+、Ca2+含量对凡纳滨对虾幼虾生长和能量收支的影响及其机制

采用人工海水,在保持海水盐度为30的条件下,设置了8个处理,R1,R2,R3,R4,R5,R6,R7和R8,其Mg2+/Ca2+比值(mg/mg)和Mg2+、Ca2+实测含量(mg/L)分别为0.11(35,330),0.53(175,330),1.59(525,330),2.42(800,330),3.36(1110,330),4.78(1110,232),7.87(1110,141),11.81(1110,94),研究了水环境Mg2+、Ca2+含量对凡纳滨对虾幼虾生长和能量收支的影响及其机制。实验持续40d(其中R8处理因为实验虾死亡率高而只进行了30d)。实验结果:对虾的生长、蜕皮、食物转化效率和能量收支受水环境Mg2+和Ca2+含量的影响均很显著(P<0.05);其摄食量受水体Ca2+浓度的影响明显(P<0.05),而受Mg2+含量的影响不显著(P>0.05)。本研究表明,凡纳滨对虾对水体低Mg2+含量的耐受能力较强,而对低Ca2+含量的耐受力很弱。在利用内陆低Mg2+或Ca2+含量的天然咸水进行对虾养殖中,通过添加Mg盐或Ca盐,只需将Mg2+浓度调节到该盐度下正常含量的15%以上,保证Ca2+浓度...     

Ca2+、Mg2+、盐度对凡纳滨对虾存活、生长及风味的影响

采取L49(78)安排7水平Ca2+、Mg2+、盐度正交试验,开展60d凡纳滨对虾养殖试验,通过比较凡纳滨对虾成活率、日均增长值、日均增重量及鲜味氨基酸含量,分析养殖水体中Ca2+、Mg2+、盐度三因子对凡纳滨对虾存活、生长及虾体风味的影响;采取L8(27)安排2水平Ca2+、Mg2+、盐度正交试验,分析养殖水体中Ca2+、Mg2+、盐度三因子间交互作用对凡纳滨对虾存活、生长及虾体风味的影响。结果表明:水体中Ca2+、Mg2+、盐度对成活率和虾体鲜味氨基酸都有显著影响(P<0.05),Ca2+、Mg2+对凡纳滨对虾生长具有显著影响(P<0.05),其中Mg2+对成活率影响最大,Ca2+对生长影响最大,而鲜味氨基酸受盐度影响最大。Ca2+浓度为100mg/L和400mg/L,Mg2+为1200mg/L,盐度为10时,成活率最高;Ca2+≥200mg/L与Mg2+≥300mg/L时,生长速度无明显变化,Ca2+浓度为100mg/L,Mg2+浓度为150mg/L,盐度为10~20时,体长和体质量增加最快;Ca2+、Mg2+含量与盐度越高,鲜味氨基酸含量越高,Ca2+浓度为400mg/L,Mg2+浓度为750mg/L,盐度为35和20时,风味氨基酸含量最高;低盐、低钙、低镁水体显著降低了凡纳滨对虾的生长存活;Ca2+与Mg2+对成活率及体质量日均增长具有显著的交互作用影响,Ca2+与盐度对成活率具有显著的交互作用影响,Mg2+与盐度对各试验指标均没有显著影响。     

低钙浓度波动对凡纳滨对虾稚虾蜕皮、生长及能量收支的影响

在实验室条件下,研究了不同Ca2+浓度波动幅度对凡纳滨对虾(Litopenaeus vannamei)稚虾蜕皮、生长和能量收支的影响。实验在水族箱内进行,实验对虾的初始体质量为(1.459±0.006)g,实验用水为人工海水,盐度为30,水温(25.0±0.5)℃,实验设恒定Ca2+质量浓度360mg/L为对照组(C360),4个实验组的Ca2+质量浓度波动幅度分别为60mg/L(C300)、120mg/L(C240)、180mg/L(C180)和240mg/L(C120),波动周期为4d。实验持续40d,主要实验结果如下:(1)不同Ca2+浓度处理下,对虾的蜕皮率存在一定的差异。其中,C120组对虾的蜕皮率最高,达(11.0±0.5)%/d,显著高于其他处理组(P0.05),而其他处理组之间差异不显著(P0.05)。(2)不同Ca2+浓度处理下,对虾的特定生长率(SGR)由大到小依次为C360、C300、C240、C180、C120。其中,C120组对虾的特定生长率显著低于其他处理组(P0.05),而其他处理组之间的差异未达到显著水平(P0.05)。(3)不同Ca2+浓度处理下,对虾的摄食率(FI)差异不显著,而对虾的食物转化效率(FCE)存在一定的差异。其中,C120组对虾的食物转化效率最低,显著低于其他处理组(P0.05),而其他处理组之间差异不显著(P0.05)。(4)不同Ca2+浓度波动对凡纳滨对虾稚虾的生长能、排粪能和蜕壳能占摄食能的比例影响显著(P0.05)。实验结果表明,水中Ca2+浓度波动幅度过大会刺激对虾蜕皮,一定程度上影响对虾的生长。     

Ca2 浓度对凡纳滨对虾稚虾生长的影响

研究了Ca2 浓度对凡纳滨对虾稚虾生长的影响。实验保持盐度15和其它离子的浓度基本恒定,共设计了5个Ca2 浓度梯度,分别为60(R1)、180(R2)、750(R3)、3750(R4)和7500 mg·L-1(R5)。经过35 d的养殖实验,结果表明:(1)不同Ca2 浓度的人工海水对凡纳滨对虾的存活率影响显著,R1组虾的存活率最低,为81.25%,显著低于R2、R3和R4的存活率;(2)5个Ca2 浓度下凡纳滨对虾生长速度不同,其特定生长率(SGRd)的大小顺序为:R3>R2>R1>R4>R5,其中R3的特定生长率(SGRd)显著高于其它4组,而R5的特定生长率(SGRd)显著低于其它4组;(3)各个处理组虾的摄食率(FId)与特定生长率(SGRd)的趋势相反,表现为R5 >R4>R2>R1>R3,其中R5的摄食率显著高于R2、R1和R3的摄食率;(4)不同Ca2 浓度对对虾的食物转化率(FCE)影响显著。Ca2 浓度最大的R5组虾的食物转化率显著低于其它各组,而R3组虾的食物转化率显著高于其它各组;(5)各组虾的生长能、呼吸能和排泄能占摄食能的比例受不同Ca2 浓度的影响显著。本实验的结果表明,Ca2 浓度是通过影响凡纳滨对虾摄食和代谢率实现对其生长能积累影响的。在对虾养殖生产中, 适当提高养殖水体的Ca2 浓度,可提高养殖效果。     

盐度对凡纳滨对虾存活、生长和能量收支的影响

研究了盐度(0·5、5、10、15、20、25、30和35)对凡纳滨对虾Litopenaeus vannamei(平均初始湿重0·776~0.781g)存活、生长和能量收支的影响。实验周期45d。结果表明,(1)对虾特定生长率、摄食量、饲料转换效率和吸收效率均以20盐度最高,而存活率以35盐度最高;(2)在0.5盐度下,对虾特定生长率、摄食量和吸收效率均最低。     

基于卤水的养殖用水中Ca2+/Mg2+对凡纳滨对虾生长及体内SOD和AKP的影响

淡水稀释取自盐场的卤水,调节Ca2 、Mg2 的质量浓度和比例,设置系列梯度,进行凡纳滨对虾的养殖试验,测定生长比速及超氧化物歧化酶(SOD)和碱性磷酸酶(AKP)的酶活性。试验表明,过高或过低的Ca2 质量浓度都会影响凡纳滨对虾的存活和生长,在Ca2 质量浓度为320 mg/L,Ca2 /Mg2 为1∶2.5时,其存活与生长最佳;同时SOD和AKP酶活性也最高。酶活性可以指示凡纳滨对虾的生长状况。     

水体中钙和镁对凡纳滨对虾幼体成活率和生长的影响

在相同饲养条件下,Ca2 浓度为494 mg/L时,幼虾增重效果显著(P<0.05);Mg2 浓度为1 185mg/L的增重效果显著优于1 135 mg/L水平;Ca2 浓度为444和494 mg/L时,分别对提高M3育成P1和P10的成活效果具有极显著作用(P<0.01);Mg2 浓度为1 185 mg/L和Ca2 浓度为494 mg/L(R=2.40)的交互作用对提高M3育成P10的成活效果最佳(P<0.01);Ca2 浓度为444和494 mg/L时,其R值可适范围分别为2.67~2.78和2.30~2.50。Ca2 浓度是影响凡纳滨对虾增重和成活的主要因子,但对体长增长无显著影响(P>0.05),其可适范围为444~494 mg/L;Mg2 浓度对凡纳滨对虾的生长影响均不显著;Ca2 浓度和Mg2 浓度的交互作用极显著影响凡纳滨对虾M3育成P10的成活率。     

低盐度条件下的凡纳滨对虾幼虾亮氨酸营养需求

为了探讨低盐度(0.6～0.8 g/L)条件下初始体质量为(0.38±0.004)g的凡纳滨对虾(Litopenaeus vannamei)幼虾的亮氨酸需求量,以鱼粉、花生麸和L-晶体氨基酸为蛋白源配制含粗蛋白400 g/kg的6种等氮饲料,标记为L7～L12组,各组亮氨酸水平分别为15.95、17.95、19.95、21.95、23.95和25.95 g/kg(饲料干物质).每组3个重复,每个重复30尾虾,进行56 d生长实验.结果表明,凡纳滨对虾幼虾的增重率随饲料亮氨酸水平的升高而升高,当亮氨酸水平达到23.95 g/kg(L11组)时,增重率达到最高值(1143.11±36.40)％,显著高于L7组(P＜0.05);亮氨酸水平继续提高,增重率变化不显著(P＞0.05).幼虾的蛋白质效率、全虾体蛋白沉积率和血淋巴总蛋白随着饲料亮氨酸水平的升高呈现升高趋势,最高值出现在L11组,并显著高于L7组(P＜0.05).各实验组饵料系数、血淋巴谷丙转氨酶、谷草转氨酶活性和尿素氮含量则呈现降低的趋势,最低值出现在L11组,且显著低于L7组(P＜0.05).以增重率为指标,根据折线模型可知,低盐度条件下凡纳滨对虾幼虾的亮氨酸最适需要量为24.80 g/kg饲料,即61.99 g/kg饲料蛋白.     

温度对不同家系凡纳滨对虾个体能量收支的影响

摄食代谢及能量收支是反映凡纳滨对虾(Litopenaeus vannamei)生长状况的重要指标,也是速生经济性状的重要选育指标。本文研究了温度(20、25、30和35℃)对凡纳滨对虾3个家系(N310004、N310010和N310011)的生长和能量收支的影响。实验周期为40 d,每隔10 d测定一次摄食率、耗氧率、排氨率和排粪率等生理指标,并分析了不同时期[S1 (0～10 d)、S2 (11～20 d)、S3(21～30 d)和S4 (31～40 d)]凡纳滨对虾家系的个体能量收支情况。结果显示,30℃时,家系N310004生长最快,总特定生长率为(9.79±0.22)%/d,S1和S4时期的特定生长率均显著高于其他2个家系(P<0.05)。温度和规格对家系的摄食和代谢有显著的影响。在实验温度范围内,各家系的摄食率和代谢率均随着温度的升高而增大。在同一温度下,除S1时期外,家系N310004的摄食率均显著高于其他2个家系。在S1和S2时期,N310011家系的耗氧率较大,在S3和S4时期,N310010家系的耗氧率显著高于N310011和N310004家系。在S1、S2和...     

Effects of constant Ca2+ concentration in salinity fluctuations on growth and energy budget of juvenile Litopenaeus vannamei

A 50-day experiment was conducted to investigate the effects of constant Ca²⁺ concentration in salinity fluctuations on growth and energy budget of juvenile Litopenaeus vannamei. The salinity and Ca²⁺ concentration of control group S0 were kept 30‰ and 385 mg l⁻¹, respectively throughout the experiment while the ranges of salinity fluctuations of the treatment groups S5 and S5C, S10 and S10C, S15 and S15C, S20 and S20C were 5, 10, 15, and 20‰, respectively. The Ca²⁺ concentration of the treatment groups S5, S10, S15, and S20 (salinity fluctuation groups) changed with salinities, while the Ca²⁺ concentration of the treatment groups S5C, S10C, S15C, and S20C (constant Ca²⁺ concentration groups) was kept 385 mg l⁻¹ during the experiment. The results were as follows: (1) There were no significant differences in SGR of shrimp in salinity fluctuation groups (P > 0.05); But shrimp in the groups S15C and S20C had significantly higher SGR than those in the groups S5C and S0 in constant Ca²⁺ concentration groups (P < 0.05); (2) Results of the t test showed that significant differences in SGR were also found between S15 and S15C (P = 0.012), and between S20 and S20C (P = 0.013); (3) The shrimp in groups S15C and S20C deposited significantly more energy for growth and spent significantly less energy in respiration than those in groups S15 and S20 (P < 0.05), respectively. These results showed that compared with constant salinity and fluctuating salinities, the growth performance of shrimp under constant Ca²⁺ concentration in large ranges of salinity fluctuations could be better.     

The effects of different Ca2+ concentration fluctuation on the moulting,growth and energy budget of juvenile Litopenaeus vannamei (Boone)

A 40‐day experiment was conducted to investigate the effects of different Ca²⁺ concentration fluctuation on the moulting, growth and energy budget of juvenile Litopenaeus vannamei with an initial wet body weight of (1.20±0.01) g. The Ca²⁺ concentration of the control group C385 was 385 mg L^?1 throughout the experiment, while the Ca²⁺ concentration of the C591, C803, C1155 and C2380 groups periodically fluctuated from 385 to 591, 803, 1155 and 2380 mg L^?1 respectively. The moulting frequency (MF) of the shrimp in the Ca²⁺ concentration fluctuating groups was significantly higher than those in the control group (P<0.05). The specific growth rates (SGR_d) and feed intake of the shrimp in the C591 and C803 groups were significantly higher than those in other groups (P<0.05), but no significant differences in feed efficiency were found among all groups (P>0.05). The shrimp in C591 and C803 groups spent significantly less energy in respiration, while depositing significantly more energy for growth than those in other three groups (P<0.05). These results showed that proper Ca²⁺ concentration fluctuation could increase the MF and growth rate of the juvenile L. vannamei, and according to the regression formula made using SGR_d and range of Ca²⁺ concentration fluctuation, periodically enhanced Ca²⁺ concentration of 295 mg L^?1 in the seawater was suggested to be used in shrimp culture.     

Effects of frequency and amplitude of salinity fluctuation on the growth and energy budget of juvenile Litopenaeus vannamei (Boone)

The effects of salinity fluctuation on the growth, intermoult period and energy budget of juvenile Litopenaeus vannamei were investigated. Salinity fluctuation regimes were set in different frequencies of 2, 4 and 8 days and different amplitudes of ±2, ±5 and ±10 g L^?1 from a control salinity of 20 g L^?1. After a 48‐day feeding trial, the intermoult period of shrimp became shorter with increasing amplitude and frequency of salinity fluctuation (P<0.05). Both the frequency and the amplitude of salinity fluctuation had a significant effect on the growth rate of L. vannamei juveniles (P<0.05). At the frequency of 4 days, the highest growth rates occurred at amplitudes of 5–10 g L^?1, whereas the growth rate was the lowest at 10 g L^?1 when the frequency was reduced to 2 days. Feed intake (FI) and assimilation efficiency (AE) of shrimp were also significantly affected by the salinity fluctuation (P<0.05) and matched the growth rate response. The energy expenditures for growth (G), respiration (R), excretion (U) and exuviae (E) to the energy consumed as food (C) were not affected by salinity fluctuation. However, salinity fluctuation significantly affected the percentage of C as faeces (F), with the lowest value occurring at salinity amplitudes of 5–10 g L^?1 and frequencies of 4–8 days. Therefore, salinity fluctuations (every 4 days by ±5–10 g L^?1) result in higher growth rates than constant salinity conditions (20 g L^?1) through greater FI, enhanced feed assimilation and reduced faecal energy loss.     

氨氮胁迫下凡纳滨对虾运动行为与能量分配模式变化

为研究氨氮胁迫下凡纳滨对虾(Litopenaeus vannamei)行为和能量分配的变化,将体质量为(4.89?0.27)g的凡纳滨对虾幼虾分别置于氨氮质量浓度为0.02 mg/L(对照)、1.00 mg/L、2.50 mg/L、5.00 mg/L,水温(28?0.5)℃的水族箱中养殖2周,监测其行为并对其生长、体组分和能量收支进行测定。结果表明,随氨氮浓度升高,凡纳滨对虾白昼的活动频率、游走距离呈先升后降趋势,而夜间则呈逐渐下降趋势,5.00 mg/L组白昼和夜间活动频率及游走距离均显著低于对照组(P0.05);特定生长率及摄食率均呈逐渐下降趋势,处理组显著低于对照组(P0.05);2.50 mg/L和5.00 mg/L组的凡纳滨对虾脂肪含量和能值均显著低于对照组(P0.05);各处理组摄食能量分配于生长的比例随着氨氮浓度的增大而降低,而消耗于代谢的比例随氨氮浓度增大而升高,与对照组相比,5.00 mg/L组的摄食能用于生长比例下降4.57%,用于代谢消耗的比例上升5.70%。上述结果表明,氨氮胁迫下凡纳滨对虾的夜间活动水平明显下降,摄食量减少,能量利用效率降低,生长速度减慢。     

Ca^2＋、Mg^2＋对凡纳滨对虾存活及生长的影响

通过单因子静态急性毒性试验和正交设计法,研究水环境中Ca~(2 )、Mg~(2 )、Ca~(2 ) Mg~(2 )总量及Ca~(2 )/Mg~(2 )比值对凡纳滨对虾存活及生长的影响。结果表明:(1)凡纳滨对虾48h的Ca~(2 )的LC_50为407.38mg·L~(-1)、Mg~(2 )的LC_(50)为741.31mg·L~(-1)。(2)在Ca~(2 )/Mg~(2 )比值为1:10时,对凡纳滨对虾生存没有影响;(3)凡纳滨对虾的生长与Ca~(2 )浓度有密切关系,其值过高或过低均会影响凡纳滨对虾的生长;在Ca~(2 )/Mg~(2 )比值为1:3时,凡纳滨对虾生长和存活率随着Ca~(2 ) Mg~(2 )质量浓度的增加而上升,但达到一定质量浓度后,又随着Ca~(2 ) Mg~(2 )质量浓度的继续增加而下降。     

密度胁迫对凡纳滨对虾稚虾免疫指标及生长的影响

将体长为（3.59±0.26）cm的凡纳滨对虾（Litopenaeus vannamei）按1 800尾.m-3、1 500尾.m-3和1 200尾.m-3的密度分别饲养在注水0.3 m3的圆形玻璃纤维桶（容量为0.5 m3）中30 d,检测了基本水质因子、对虾肝胰腺和肌肉组织中的酚氧化酶（PO）活力、超氧化物歧化酶（SOD）活力、抗菌活力（Ua）、碱性磷酸酶（AKP）活力、体质量增长和成活率,研究了不同放养密度对凡纳滨对虾稚虾免疫指标及生长的影响。统计分析发现,试验过程中水体理化因子均在适宜范围,各处理间水质因子的差异不显著;对虾的PO活力、Ua和AKP活力均随着密度的增加而降低,SOD活力则反之;对虾的体质量增长、体质量特定增长率和成活率随着密度的增加而降低,成活率差异显著（P〈0.05）。结果表明,凡纳滨对虾（体长〈4.8 cm或体质量〈1.2 g）在密度为1 200～1 800尾.m-3时,密度胁迫可明显影响其免疫指标和生长。