Abstract:

Amino acids composition and activities of four digestive enzymes including pepsin, tryptase, amylase, cellulase were determined in the eggs of freshwater prawn, Macrobrachium nipponense. These eggs were sampled from different embryonic development stages. The results indicated that digestive enzymes activities and amino acids correlated closely with the stages of embryonic development. Activities of pepsin, tryptase and amylase were relatively high during the whole embryonic development stages. Activities of pepsin, tryptase and amylase were high in early and late developmental stages, but relatively low during middle stages. Cellulose activity was low and showed no obvious change during different embryonic development stages. During protozoea stage, activities of pepsin, tryptase and amylase increased obviously. The content of dissolvable protein and amino acid had a decreased trend. It had relevance to the activities of related enzymes. However, content of the dissolvable protein and amino acid during gastrula stage were higher than that of during blastula stage. Among all the amino acids determined, content of Glu was the highest, the highest essential amino acid (EAA) content was Leu. There was little difference between the ratios of content of single EAA to total EAA during different stages of embryonic development of M. nipponense.

Key words: embryonic development, digestive enzyme, amino acid, Macrobrachium nipponense, embryonic development, digestive enzyme, amino acid