Research Article: Effect of dietary trypsin extracted from the viscera of yellowfin sea bream, (Acanthopagrus latus) on growth performance, body composition, and digestive trypsin activity in Sobaity sea bream (Sparidentex hasta) larvae

In this study, trypsin was extracted from the viscera of yellowfin sea bream (Acanthopagrus latus) and used as an additive in Sobaity sea bream, Sparidentex hasta, larvae microdiet. The microdiet was supplemented with the extracted enzyme and its efficiency was evaluated in the growth performance of S. hasta larvae. There were five treatments containing zero (control), ۱۰۰۰, ۱۵۰۰, and ۲۰۰۰ IU/kg of the extracted trypsin with ۵۰۰ IU/kg of a commercial diet of porcine trypsin. S. hasta larvae (mean initial weight of ۰.۰۲۱±۰.۰۰۱ g) were fed with experimental diets for ۲۸ days. Fifteen round polyethylene tanks (۳۰۰ L, a water volume of ۱۰۰ L) equipped with a water circulation system and an air stone were used for the treatments. The highest body weight gain (BWG), specific growth rate (SGR), daily growth, survival rate, and protein efficiency ratio (PER) were observed in the larvae fed the diet containing ۲۰۰۰ IU/kg trypsin (p<۰.۰۵). In addition, the lowest and the highest values of the feed conversion ratio (FCR) vs daily feed intake and trypsin activity were significantly recorded in ۲۰۰۰ IU/kg trypsin and the control groups, respectively (p<۰.۰۵). A positive correlation was observed between the increasing levels of trypsin in the microdiets and growth performance (i.e. BWG, SGR, daily growth rate, survival rate, and PER). Besides, the dietary addition of external trypsin reduced the values of FCR, daily feed intake, and trypsin activity in the larvae. Overall, trypsin at different doses, particularly at ۲۰۰۰ IU/kg, can significantly improve the performance and feed utilization of S. hasta larvae.

کلیدواژه ها:

Sparidentex hasta ، Weight gain ، Protease enzyme ، Microdiet ، Correlation coefficient.