养殖水温对星洲红鱼生长、消化和免疫的影响

Effects of Cultural Water Temperature on Growth,Digestion and Immune of Singapore Red Tilapia(O.mossambicus)

为研究不同养殖水温对星洲红鱼的生长、消化和免疫的影响，选取300尾体长为（12．5±1．5）cm，体重为（25．1±2．3）g的健康星洲红鱼分别在温度为15、20、25、30和35℃的水体中饲养40d。每一温度设3个重复，每个重复20尾星洲红鱼。结果表明：各养殖水温下星洲红鱼的特定生长率表现为30℃〉35℃〉25℃〉20℃〉15℃，且组间差异显著（P〈0．05）；特定生长率（y）与养殖水温（x）的回归关系为：y=-0．1182x^3＋0．917x^2-1．4575x＋1．0827（r=0．9978）。各组星洲红鱼的成活率为86．67％-98．33％，在15℃时最高，在35℃时最低，除30与25℃组间差异不显著（P〉0．05）外，其他组间差异显著（P〈0．05）。饲料系数表现为35℃〉25℃〉30℃〉20℃〉15℃，除15和35℃组间差异显著（P〈0．05）外，其他组间差异不显著（P〉0．05）。随养殖水温从15℃升高到30℃，各组肌肉RNA／DNA逐步上升，在35℃时又有所下降，除15与20℃组间差异不显著（P〉0．05）外，其他组间差异显著（P〈0．05）。星洲红鱼肝胰腺、肠和胃蛋白酶、淀粉酶和脂肪酶活性均随养殖水温的升高先上升后下降，其中蛋白酶和淀粉酶活性在30℃以后开始下降，而脂肪酶活性在25℃以后开始下降。除25和35℃组的淀粉酶活性以及20与30℃组的脂肪酶活性差异不显著（P〉0．05）外，各消化酶活性在各组间差异显著（P〈0．05）。星洲红鱼血清酸性磷酸酶（ACP）、碱性磷酸酶（AKP）、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性均在30℃达到最高，在35℃时间有所下降。除血清SOD活性外，血清AKP、ACP和POD活性在25和35℃组间差异不显著（P〉0．05），其他组间差异显著（P〈0．05）。由此得出，养殖水温在27-34℃时星洲红鱼生长快、消化能力强、免疫相关酶活性高；通过回归分析得出，当养殖水温为31℃时星洲红鱼的生长最佳。

In order to study the effects of different cultural water temperature on growth, digestion and immunes of Singapore red tilapia （ 0. mossambicus）, a total of 300 healthy Singapore red tilapia with the body weight of （25.1±2.3） g and body length of （12.5±1.5） cm were cultured at the water temperature was 15, 20, 25, 30 and 35 ℃ for 40 days, respectively. Each temperature had 3 replicates, and each replicate had 20 fish. The results showed that there was significant difference in the specific growth rate （SGR） at different cultural water temperature （P〈0.05）, which was 30 ℃ 〉35 ℃ 〉25 ℃〉20 ℃ 〉15 ℃. The regression relation of SGR （y） and cultural water temperature （x） was： y=-0.118 2x^3＋0.917x^2-1.457 5x＋1.082 7 （r=0.997 8）. The survival rate was 86.67% to 98.33% at different temperature, and the highest survival rate was at 15 ℃ and the lowest survival rate was at 35 ℃, in which there was significant difference among different temperature groups （P〈0.05） except 30 and 25 ℃ groups （P〉0.05）. The feed conversion ratio at different temperature was 30 ℃ 〉35 ℃ 〉25 ℃ 〉20 ℃ 〉15 ℃, in which there was no significant difference among different temperature groups （P〉0.05） except 15 and 35 ℃ groups （P〈0.05）. The muscle RNA/DNA was increased with cultural water temperature increasing from 15 to 30 ℃, and then decreased at 35 ℃, in which there were significant difference among different temperature groups （P〈0.05） except 15 and 20 ℃ （P〉0.05）. The activities of protease, amylase and lipase of hepatopancreas, intestine and stomach were firstly increased and then decreased with cultural water temperature increasing, in which the activities of protease and amylase were decreased after 30 ℃ and the activity of lipase were decreased after 25 ℃. There were significant difference among different temperature groups （P〈0.05） except amylase activity at 25 and 35℃ groups and lipase activity at 20 and 30℃ groups （P〉0.05）. The activities of alkaline phosphatase （AKP）, acid phosphatase （ACP）, superoxide dismutase （SOD） and peroxydase （POD） in serum had the highest values at 30 ℃, and decreased at 35 ℃. Except serum SOD activity, there was significant diffenences in the activities of AKP, ACP and POD among different temperature groups （P〈0.05） except 25 and 35 ℃ groups （P〉0.05）. Therefore, Singapore red tilapia grow faster with stronger digestive ability and higher immune enzyme activities when the water temperature is 27 to 34 ℃. Regression anaylsis result shows that Singapore red tilapia has the best growth when the water temperature is 31 ℃.