Feed formulation depending on the ontogenic development of crayfish (astacus leptodactylus)

The objective of this study is to determine the digestive enzyme activities in different developmental stages of freshwater crayfish Astacus leptodactylus, to come up with an appropriate feed formulation for its nutritional requirements and hence. During the embryonic development of A. leptodactylus, protease, trypsin and alkaline phosphatase enzyme activities were investigated and it was found that the enzyme activities showed changes depending on the development of the embryo. Two peaks were observed in protease activity in stage VIII and XIV. Trypsin activity was generally high until the middle of embryonic development and reached its peak in stages XII and XIV. Alkaline phosphatase activity remained at low levels until the end of embryonic development and reached high levels in stage XIII and XIV. These results showed that the digestive enzyme activity patterns of A. leptodactylus during embryonic development stages were related to organogenesis and physiological functions. The protease, acid protease, trypsin and alkaline phosphatase activities in the different development stages (stage I-VI) of A. leptodactylus juveniles were also investigated and all enzymes were found to be present before exogenous feeding (stage I) started. Enzyme activities changed depending on the developmental stages of the juveniles and the highest increase in all enzyme activities was observed during development stage IV. Proteaz activity increased significantly and reached its maximum in stage V after juveniles started their exogenous feeding period. Acid protease values showed significant differences in the pH levels selected in the study (P < 0.0001) and the highest acid protease activity was determined at pH 3 in all stages.The maximum increase in trypsin and alkaline phosphatase enzyme activities were observed in stage IV. In addition, the effects of different feed raw materials on protease activity were evaluated and the most suitable animal (fish hydrolyzate, imported fish meal, gammarus, squid meal, krill meal) and plant (corn gluten, wheat glüten, wheat meal) raw materials which could be used in the feed formulation were determined. An ideal feed formulation was formed with the determined feed raw materials and microdiet production was provided.