en aquaculture aquaculture پژوهشي Orginal research papers <div style="text-align: justify;"><span style="font-size:11pt"><span style="line-height:120%"><span style="font-family:Calibri,sans-serif"><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="color:black">In this study, alkaline, neutral, and acid enzyme activities, molecular weight distributions, and proximate compositions of live feeds were determined in a time-dependent manner. Samples were taken from three different live feeds and <i>Artemia</i> cysts. R refers to rotifer, A-0 refers to non-enriched <i>Artemia</i> / <i>A</i>. nauplii, and A-1 refers to enriched <i>Artemia</i> / <i>A</i>. metanauplii. Sampling was done at 0^th, 6^th, 12^th, and 18^th h (T) and before enrichment as R (R-0) and A1 (A1-0). </span></span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="color:black">Depending on time, while enriched rotifers have high acid enzyme values at pH 3 and 4, neutral and alkaline enzyme values of enriched <i>Artemia</i>s were higher (<i>p<</i>0.05).&nbsp; Time-dependent decreases were detected in the enzyme activities of enriched <i>Artemia</i> and rotifers.&nbsp; Live feeds enriched for up to 12 hours should be used with a molecular weight fraction of 2,532 Da&ge;&nbsp; (<i>p<</i>0.05).&nbsp; When marine finfish such as European sea bass and gilthead sea bream are started feeding, their digestive enzymes have alkaline and then acid characteristics. On the other hand, in this study, it was determined that rotifer enzymes had higher acid protease activities and <i>A</i>. metanauplii had higher alkaline protease enzyme activities. Considering this situation, <i>A</i>. nauplii should be given together with rotifers and <i>A</i>. metanuplii should be started as soon as possible. In addition, considering the enzyme activity values of the rotifers used as the first feed, the use of rotifers that are not enriched in terms of the contribution of live feeds to the larval digestive system should also be taken into account.</span></span></span></span></span></span></span></div> Protease, Molecular weight, Proximate, Rotifer, Artemia, Live feed 1241 1266 http://jifro.ir/browse.php?a_code=A-10-1766-2&slc_lang=en&sid=1 G. Diken gurkandiken@isparta.edu.tr 100319475328460046540 100319475328460046540 Yes Isparta University of Applied Sciences, Faculty of Eğirdir Fisheries, 32260 Isparta, Turkey