Effects of starvation on biochemical compositions and digestive enzyme activities of spotted babylon, Babylonia areolata juveniles

An experiment was conducted to determine the effects of starvation on biochemical compositions,energy values and activities of protease,lipase and amylase of the digestive system of Babylonia areolata juveniles during a period of 120 days.The results indicated that water and ash contents in the whole soft body increased gradually,while the contents of protein,lipid and glycogen,as well as the energy values,decreased greatly during starvation.The total lipase activity obtained from stomach,intestine and hepatopancreas was higher than that from the control when the snails were deprived for 10 days;it decreased markedly during starvation,and the total activities of amylase and protease reduced gradually with prolonged starvation period.The relative activity percentages were 70.12% and 63.66% for lipase and amylase when compared to the control after being starved for 70 days,whereas the responding value was 42.79% for protease.The activities of lipase and amylase showed a marked decrease from the 70th to the 90th day;they remained stable relatively thereafter.In conclusion,the lipid and glycogen contents were mobilized greatly during early growth period,while the protein was metabolized when the snails were starved longer than 70 days and served as the predominant energy source 90 days later.The total digestive enzyme activities of all three kinds maintained at lower level from the 90th to 120th day after a rapid decrease,and the water content could be used as an effective marker to estimate the nutrient status of the snails during starvation period.