Development of Enzymes andIn VitroDigestibility during Metamorphosis and Molting of Blue Swimming Crab (Portunus pelagicus)

Abstract

The work focuses on development of digestive enzymes (amylase, total protease, trypsin, and chymotrypsin) and activity ratio of trypsin to chymotrypsin (T/C ratio) for digestive efficiency and growth, in blue swimming crab (Portunus pelagicus) during metamorphosis and molting. Specific activities of all enzyme parameters studied were associated with growth during metamorphosis, while only those of trypsin and T/C ratio were associated during molting cycle where trypsin and chymotrypsin specific activities associated with consumption rate with especially high levels during late intermolt and early premolt stages. About 50% increased weight gain was observed with at least double increased T/C ratio at the end of molting period, compared to the stages prior to molting. Growth of carapace would be more significant after finishing molting. Carapace width gain and T/C ratio were highest at the first crab stage. Studies ofin vitroprotein digestibility of different feed raw materials indicated thatArtemia, Rotifer, andMoinaare the best for larval stages. Otherwise, the use of shrimp feed andArtemiaflake could be the alternatives. Incorporating of cassava meal into the feed formula for early adult stage (juvenile) could be an advantage. The proteins from animals are more beneficial for adult crab culture than the proteins from plants and bacteria. The digestible quality of dietary protein is very important during larval stages, while the protein level of diet is more important during adult stages with fully developed digestive enzymes.

Optimal protein replacement of fish meal by mackerel condensate in diet for giant freshwater prawn (Macrobrachium rosenbergii)

“…; Rungruangsak‐Torrissen et al . ) and in blue swimming crab, Portunus pelagicus (Chamchuen, Pratoomchat, Engkakul, Kovitvadhi & Rungruangsak‐Torrissen ). However, no correlation between this ratio and growth was observed in Siamese fighting fish ( Betta splendens ) fed various modified diets (Thongprajukaew et al .…”

Optimal Dietary Protein Requirement for Juvenile Sesarmid Crab (Episesarma singaporense)

“… * The optimal conditions were chosen from previous reports in spider crab, Maja brachydactyla [ 23 ]; blue swimming crab, Portunus pelagicus [ 24 ]; and green crab, Carcinus mediterraneus [ 25 ]. ** Determination of pepsin-like [ 26 ], trypsin [ 27 ], chymotrypsin [ 27 ], amylase [ 28 ] and lipase [ 29 ] activities were conducted following the previous publications.…”

Neural computational model GrowthEstimate: A model for studying living resources through digestive efficiency

“…The levels of T/C ratio values increase with growth potential, and younger animals have higher growth potential than older ones. This has been clearly observed during the molting period and metamorphosis, respectively, in the blue swimming crab Portunus pelagicus L. [14]. Therefore, the age of the growth stage specified through the animal body weight at sampling is important for growth rate estimation.…”

“…Growth performance quality is dependent not only on weight, but also on the protein utilization and deposition affecting the CF values of living resources. However, protein utilization and growth are influenced by protein digestive efficiency (T/C ratio), whereas both trypsin and chymotrypsin specific activities are dependent on dietary protein levels [13] and food consumption rates [14]. With increasing nonlinear factors and unknown individual fishes, the estimation of SGR as nonlinear temporal data using conventional techniques with only the weight and time interval, commonly performed in aquaculture as in [5] and [6], becomes unsuitable.…”