Các thông số di truyền tính trạng tăng trưởng trên cá rô phi đỏ (Oreochromis spp.)

Đề tài ‘Đánh giá các thông số di truyền và hình thành vật liệu ban đầu cho chọn giống cá rô phi đỏ (Oreochromis spp.)’ tập trung vào việc tạo quần thể ban đầu của cá rô phi đỏ tại Đồng bằng sông Cửu Long cho hai môi trường nuôi nước ngọt và nước lợ mặn. | VIỆN NGHIÊN CỨU NUÔI TRỒNG THỦY SẢN 2 EFFECT OF FISH DENSITY AND FEEDING LEVEL ON GROWTH AND SURVIVAL RATE OF STRIPED CATFISH Pangasianodon hypophthalmus NURSING FROM 21-DAY FRY TO FINGERLING Nguyen Van Sang1 Nguyen The Vuong2 ABSTRACT This study determines optimal stocking density and feeding level for best survival rate and growth rate for fingerling nursed from 21-day fry. 21-day fry was assigned in 3-m2 hapa fixed in one earth- ern pond. Six fish densities 100 con m2 125 con m2 150 con m2 175 con m2 200 con m2 and 225 con m2 and two feeding levels were conducted in 3 replicates. Experimental period was 90 days and recording was conducted every month. The differences in survival rate and growth rate were eva- luated by ANOVA analysis in Minitab. Fish density influenced significantly on first-month survival and whole nursing period while it did not influence significantly on second-month and third-month survival. Fish density influenced significantly on growth rate in term of body weight body length and SGR in all nursing period. Feeding level did not influence significantly on survival. Feeding level influenced significantly on body weight and body length at high fish density in the first month third month and at most of treaments for whole nursing period. Fish density of 100 con m2 was optimal in this study and in addition feeding at level 1 8 7 6 body weight day according to month one two and three or level 2 7 6 5 body weight day according to month one two and three resulted in high survival high growth rate and low FCR. Keywords striped catfish fingerling density feeding level growth rate survival rate. Người phản biện TS. Phạm Văn Khánh Ngày nhận bài 11 9 2013 Ngày thông qua phản biện 25 9 2013 Ngày duyệt đăng 15 10 2013 1 Research Insitute for Aquaculture Email nguyenvansang1973@ 2 National Breeding Center for Southern Freshwater Aquaculture Research Insitute for Aquaculture TAÏP CHÍ NGHEÀ CAÙ SOÂNG CÖÛU LONG - 2 - THAÙNG 11 2013 23 .