THE INCLUSION OF UREA-TREATED PALM KERNEL MEAL AS A FEED INGREDIENT IN THE DIET OF JUVENILE SEABASS (LATES CALCARIFER) AFFECTS GROWTH PERFORMANCE

摘要

A 56-day feeding trial was conducted to evaluate the effect of using palm kernel meal (PKM) and chemically-treated PKM using urea (UTPKM) as feed ingredients in diets on the growth performance of juvenile seabass Lafes calcarifer. Seven isonitrogenous(45 % crude protein), isoenergetic (19 kJ g-1) and isolipidic (10 % crude lipid) practical experimental diets were formulated. The control diet (Diet 1) did not contain any PKM and the other six diets were formulated to have either raw PKM or UTPKM at 7.5 %, 15.0 % or 22.5 % of the diet respectively, at the expense of solvent-extracted soybean meal. Danish fish meal was included at 39.7% for all diets so that at least 60% of the total dietary protein came from animal protein. Growth performance of seabass juveniles with initial weight of 49.8 ± 0.2 g (mean ± s.d.) fed the control diet, 7.5 % PKM and 15 % PKM or 7.5 % UTPKM, 15 % UTPKM and 22.5 % UTPKM diets showed similar growth (p > 0.05) and better performance than fish fed the 22.5 % PKM diet (p< 0.05). Mean final weights of seabass fed all diets except 22.5 % PKM diet were not significantly different (p > 0.05) compared to seabass fed with the control diet. Similar trends were observed in terms of percent weight gain and specific growth rates.On the other hand, in terms of protein efficiency ratio (PER) and net protein utilization (NPU), there were significant differences (p < 0.05) among all dietary treatments with the control diet giving the highest PER and NPU offish compared to fish fed15.0 % PKM or 22.5 % PKM. Nevertheless, the PER and NPU offish fed with either 7.5 % PKM, 7.5 % UTPKM or 15 % UTPKM showed similar performance with the control diet (p > 0.05). It was concluded that PKM is a potential partial replacement for soybean mealin the diets of juvenile seabass and that urea treatment of PKM may further improve the utilization of this by-product from the palm industry.