Effects Of Different Diets On Digestive Enzyme Activities, Growth Performance, And Survival Rate Of Brandt’s Rice Crab Juvenile (Somanniathelphusa Germaini)

Abstract

Brandt’s Rice crab (Somanniathelphusa germaini) is a potential species for aquaculture in the Mekong delta. This study was conducted to determine appropriate diets for growth and survival of rice crab at juvenile stage. The experiment consisted of 5 treatments, all treatments were designed and set up randomly in triplicate in 0.25 m² tanks. Five different types of feed were evaluated including (1) tubifex, (2) Artemia biomass, (3) tubifex + artificial feed, (4) Artemia biomass+ artificial feed and (5) artificial feed. Key digestive enzymes (trypsin, chymotrypsin, pepsin, lipase, and amylase) were measured. After 28 days of rearing, the results showed that water quality parameters were in appropriate range for crab performance. The digestive enzyme activities were fluctuated baseing on feed compositions, in which, trypsin, pepsin, lipase and amylase were important indicators. Crabs fed tubifex were recorded with the highest survival rate (80.0 %), growth performance (CW = 10 mm and W=0.3 g) and productivity (400 ind./m²), which were significantly higher than other treatments (p<0.05). Besides, the artificial feed was not suitable for crab rearing, leading to low growth and survival. The results suggested that tubifex could be applied for the husbandry practice of rice crab nursery.