Nirut Sukasem and Jareeporn Ruangsri

pp. 1283 - 1299

Abstract

Effects of Palm Kernel Cake (PKC) on growth performance, blood components and liver histopathology of sex- reversed red tilapia Oreochromis niloticus were studied using seven isocaloric diets (3400
kCal/ kg) containing different levels of protein and PKC. Diet 1, 2 and 3 contained 20% protein with the supplementation of 15, 30 and 45% PKC, respectively. Diets 4, 5 and 6 contained 24% protein in combination
with the same PKC supplemention levels mentioned above, and diet 7 was commercial feed containing 20% protein as a control diet. Experimental diets were fed to experimental fish of 48.65 g initial average body
weight cultured in floating cages (3 cages/diet) for 10 weeks. Fish fed diets containing higher protein (24%; diets 4, 5 and 6) had significantly better growth performance (p<0.05) than those fed lower protein (20%; diets 1, 2 and 3). Considering the effect of PKC, fish fed diet 5 (Prot. 24%, PKC 30%) gave the greatest growth performance (p<0.05) and all the PKC-fed groups had significantly higher growth than fish fed control diet. There was evidence that supplementation of PKC in fish feed ranging from 15 to 45% had no effect to the survival rate, blood components, or hepatocytic cells of tilapia. However, liver tissue showed higher numbers of lipid droplets in fish fed diet contained 45% PKC (diets 3 and 6). For the production cost,
all test diets with PKC supplementation had significantly higher price (p<0.05) than commercial feed. However, when considering the feeding cost per unit of fish production, fish reared with PKC supplemented diets had significantly lower cost (p<0.05) than fish fed commercial feed.