Effects of partial replacement of fishmeal protein by protein extracted from green seaweed (Cladophoraceae) in mudskipper (Pseudapocryptes elongatus) diets

Abstract

 The study was conducted to assess the possible utilization of protein extracted from green seaweed (Cladophoraceae) in mudskipper (Pseudapocryptes elongatus) diets. The fishmeal (FM) protein was replaced by protein extracted from green seaweed (EGW) at graded levels of 15, 30, 45 and 60%. The diet without green seaweed protein considered as a control treatment. All experimental feeds were formulated to be equivalent in crude protein (30%) and lipid (7%). Fish with average initial weight of 0.43 g were reared in the 100-L tank at a density of 30 fish per tank and salinity of 10 ppt, fed ad libitum twice a day. After 45 days of feeding trial, survival of experimental fish was not affected by the feeding treatments, varied in the ranges of 91.1- 94.4%. When fishmeal protein was replaced from 15% to 45% of protein extracted in the diets, growth rate of fish were better or similar to those in the control diet. Although feed conversion ratio (FCR) increased and protein efficiency ratio decreased with increasing levels of FM substitution from 30% upwards, statistical differences were not observed among feeding treatments. The proximate composition of fish fillet such as the moisture, lipid, and ash contents tended to decrease with increasing level of EGW protein while the protein contents slightly increased at higher inclusion of EGW protein in the diet from 15% to 45%. The present study indicated that protein extracted from green seaweed (Cladophoraceae) could replace fishmeal protein up to level of 45% in formulated feed for the mud skipper (P. elongatus) diets.