Low dietary protein to energy ratios support rapid growth of Juvenile topshell, Trochus niloticus

Abstract

Nine practical diets containing nine protein-to-energy ratio of 0.058, 0.064, 0.077, 0.088, 0.097, 0.100, 0.115, 0.120, and 0.155 g/kcal were fed at 5-3% of body weight daily to juvenile topshell, T. niloticus, for 90 days. Protein to energy ratio had significant effects on growth and nutrient deposition of juvenile topshell, Trochus niloticus. At P:E ratio of 0.058 and 0.064 g/kcal, SLG reached 0.20-0.21 mm, WG 7.18-9.69%, SGR 0.080.10% day -1 , and attained PER of 0.48–0.57. Survival (82-92%) and feed conversion ratios (5.81-6.77) were not affected by P:E ratio in the diet. Nutrient deposition was significantly affected by P:E ratio in the diet. High protein deposition was observed at P:E ratio of 0.058 g/kcal, while high fat deposition was observed at P:E ratio of 0.155 g/kcal. This study demonstrated that a P:E ratio of 0.058 and 0.064 g/kcal was sufficient for good growth, PER and high crude protein deposition in juvenile topshell, T. niloticus.