光合细菌PS2对尖吻鲈的生长、消化酶及非特异性免疫酶的影响

研究了光合细菌对尖吻鲈（Latescal carifer）的生长、消化酶及血清免疫酶活性的影响。把浓度为8×10^8cfu·mL^-1的荚膜红假单胞菌（Rhodopseudomonas capsulate）的液体制剂分别以0．0％（对照组）、0．5％、1．0％和1．5％的比例添加到饲料中，投喂初始体质量为（10．95±0．25）g的尖吻鲈50d。鱼的增重率、特定生长率、成活率及饲料系数在组间均没有显著性差异（P〉0．05）。肝蛋白酶、肠淀粉酶及胃淀粉酶在1．0％组显著高于对照组（P〈0．05）；肠蛋白酶在1．5％组显著低于1．0％组（P〈0．05），但试验组与对照组间没有显著性差异（P〉0．05）；幽门垂的消化酶在1．5％组显著高于其他各组（P〈0．05）。血清碱性磷酸酶（AKP）、过氧化物酶（POD）和超氧化物歧化酶（SOD）的活性在组间均没有显著性差异（P〉0．05）。结果表明，该株光合细菌对尖吻鲈的生长及非特异性免疫力没有显著影响，但在1．5％组能显著促进其幽门垂消化酶的活性，在1．0％组显著促进肝蛋白酶及肠和胃淀粉酶的活性。

Effects of dietary photosynthetic bacteria PS2 on growth performance,digestive enzymes and nonspecific immune enzymes of sea bass(Lates calcarifer)

The research evaluated the effects of photosynthetic bacterium PS2 on the growth performance, digestive enzymes and serum nonspecific immune enzymes of cultured sea bass （Lates calarifer）. Four levels of Rhodopseudomonas capsulate liquid product at concentration of 8 × 10^8cfu·mL^-1 were supplemented to a basal diet at 0.0 % （control group） , 0.5% （group 1 ） , 1.0 % （group 2 ） and 1.5 % （group 3 ）, respectively. Diets were fed to the sea bass with initial body weight of （10. 95±0.25 ） g for 50 days. The results showed that there was no significant difference in the weight gain, specific growth rate, survival rate and feed conversion ratio among all experimental groups （ P 〉 0. 05 ）. The liver protease, intestinal and stomach amylase of group 2 were significantly higher than those of the control group （ P 〈 0. 05 ）. The intestinal protease of group 3 was significantly lower than that of group 2 （ P 〈 0. 05 ） , but there was no significant difference between the experimental group and the control group （ P 〉 0.05 ）. The pyloric caeca digestive enzymes of group 3 were significantly higher than those of the other groups （ P 〈 0.05 ）. There was no significant difference in serum AKP, POD and SOD among the groups （ P 〉 0.05 ）. The results indicated that photosynthetic bacterium PS2 had no significant effects on the growth performance and nonspecific immune ability of the sea bass, but it could significantly promote the activity of digestive enzymes of pyloric caeca in group 3 and improve that of the liver protease, intestinal amylase and stomach amylase in group 2 （ P 〈 0. 05 ）.