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.