间歇性干旱对福寿螺生长、抗氧化能力和消化酶活性的影响

福寿螺(Pomacea canaliculata)是首批列入我国外来入侵物种黑名单的生物。本文采用干旱后复水方式喂养福寿螺48 d,研究间歇性干旱处理下福寿螺摄食生长、肝胰脏抗氧化能力及胃消化酶活力变化。结果显示:间歇性干旱能够显著降低福寿螺的体重增长率,对存活率影响不明显;福寿螺在恢复摄食期间出现部分补偿生长现象,主要是通过复水后增大摄食量来实现的,当间歇性干旱时间间隔延长到8 d时,则是通过增大摄食量和提高食物转化率的双重作用来实现的;除间隔4 d间歇性干旱下SOD酶活力以外,福寿螺在短间隔(1~4 d)间歇性干旱下SOD和CAT活力均出现不同程度的增加,而MDA含量明显降低;在长间隔(8 d)间歇性干旱下,SOD和CAT活力均低于对照组,且MDA含量与对照组无差别;间歇性干旱降低了福寿螺肝胰脏中GST和GSH-PX活性,对GSH含量无明显影响;除间隔1 d的处理组胃脂肪酶外,间歇性干旱能够不同程度地提高福寿螺胃淀粉酶和胃脂肪酶活力。总体而言,在间歇性干旱胁迫下,福寿螺可通过提高摄食率、食物转化率、抗氧化能力、消化酶活性等,在一定程度上来缓解胁迫带来的影响,但间歇性干旱能够明显抑制福寿螺的正常生长,表明通过农田水位交替性变化可在一定程度上防控福寿螺的暴发与危害。

Effect of intermittent drought on growth, antioxidant capacity and digestive enzyme activity of Pomacea canaliculata

Golden apple snail (Pomacea canaliculata) was included in the first class of blacklisted invasive alien species in China. In a 48-day period of intermittent drought experiment with different drought-flooding intervals, drought-flooding treatments were carried out to examine changes in growth, antioxidant capacity and digestive enzyme activities of P. canaliculata. The results showed that intermittent drought significantly reduced the increase rate of weight without obviously influencing survival rate of snails. Snails compensated growth mainly by increasing food consumption during re-feeding period under flooding conditon. When intermittent drought duration was extended to 8 days, compensatory growth started by increasing feed intake and enhanced food conversion ratio. Except for the activity of superoxide dismutase (SOD) in 4-day interval treatment, intermittent drought treatments with short intervals (1 4 days) improved SOD and catalase (CAT) activities in hepatopancreas while decreasing the content of malondialdehyde (MDA) in snails. However, SOD and CAT activities in 8-day interval treatment were lower than those of the control group, but MDA content was not significantly different compared with the control. The levels of glutathioneperoxidase (GSH-PX) and glutathione-S- transferase (GST) in the liver of snail dropped down under different intermittent drought stress treatments while glutathione (GSH) content remained unchanged. Except for lipase activity under 1-day interval treatment, intermittent drought treatments also improved amylase and lipase activities on different levels in the stomach of snails. In conclusion, snails enhanced feed intake, food conversion ratio, antioxidant capacity and digestive enzyme activity to protect them from the intermittent drought stress. However, this form of stress significantly influenced normal feeding and growth processes of snails. The findings pointed to the possibility to control snail occurrence and to decrease its damage by periodically regulating water levels in paddy fields.