Subsequently, BPE was lyophilized using a freeze-dryer (Eyela, FDU-1100, Tokyo, Japan) before administrating in diets. The extract (BPE) was composed of crude protein (7.71 ± 0.30%), crude lipids (0.46 ± 0.03%), moisture content (14.45 ± 0.18%), ash (27.21 ± 0.11%) and total carbohydrate 50.17 ± 0.15%, and was stored at 20 C until being used.