ẢNH HƯỞNG CỦA CÁC TỶ LỆ THAY THẾ THỨC ĂN CÔNG NGHIỆP BỞI BÈO CÁM (Lemna minor) LÊN SINH TRƯỞNG VÀ HIỆU QUẢ SINH SẢN CỦA ỐC BƯƠU ĐỒNG (Pila polita Deshayes, 1830) NUÔI VỖ TẠI THỪA THIÊN HUẾ

Abstract

This study aimed to evaluate the partial replacement of commercial feed (CF) by duckweed (DW) in diets to cultivate black apple snail broodstocks. Snails were fed with four diets with the replacement of CF by DW at different levels of 75% CF + 25% DW (NT25), 50% CF + 50% DW (NT50), 25% CF + 75% DW (NT75) and 100% CF (NTCN). Each treatment was repeated three times. After a cultured period of 75 days, the specific growth rate of snails was highest in NT25 (0.55 %/day), followed by NTCN (0.54 %/day) and significantly different (p<0.05) compared to those in NT50 (0.50 %/day) and NT75 (0.48 %/day). Similarly, the gonadosomatic index of snails was the highest in NT25 (10.0% in females; 4.16% in males), followed by NTCN (9.90% in females; 4.09% in males) and significantly different (p<0.05) as compared to those in NT50 (9.40% in females; 3.89% in males) and NTCN (9.32% in females; 3.84% in males). The reproduction efficiency of snails was highest in NT25 (10.33 clutch/m²), followed by NTCN (10.0 clutch/m²), and significantly different (p<0.05) as compared to those in NT50 (8.33 clutch/m²) and NT75 (8.0 clutch/m²). Results show that it is possible to replace CF by DW at the level of 25% in the diets of the black apple snail broodstocks to improve the growth rate and reproductive efficiency.