Ảnh hưởng của mật độ ương đến sinh trưởng và tỷ lệ sống của ấu trùng ngao dầu (Meretrix meretrix Linnaeus, 1758) từ giai đoạn bơi tự do (D-veliger) đến giai đoạn sau biến thái (post-metamorphosis)=Effect of stocking density on growth and survival rate of larvae of clam (meretrix meretrix linnaeus, 1758) from d-veliger to post metamorphosis stages

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Tác giả: Đức Thuần Lê

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Nông nghiệp và Phát triển nông thôn, 2024

Mô tả vật lý: tr.60-67

Bộ sưu tập: Metadata

ID: 476024

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Nghiên cứu nhằm xác định ảnh hưởng mật độ đến sinh trưởng và tỷ lệ sống của ấu trùng ngao dầu ( Meretrix meretrix ) từ giai đoạn bơi tự do (D-veliger) đến giai đoạn sau biến thái (chuyển sang đời sống vùi đáy). Thí nghiệm được tiến hành với 4 mật độ ương khác nhau, lần lượt là: 10 ấu trùng/ml, 15 ấu trùng/ml, 20 ấu trùng/ml và 25 ấu trùng/ml, mỗi nghiệm thức được bố trí 3 lần lặp. Ấu trùng ngao được ương trong 12 bể nhựa 120 L (thể tích thí nghiệm 100 L). Thí nghiệm được tiến hành trong 7 ngày, vào tháng 6/2024, tại Trung tâm Nghiên cứu Khảo nghiệm và Dịch vụ vật nuôi, Viện Nông nghiệp tỉnh Thanh Hóa. Kết quả nghiên cứu cho thấy, ấu trùng ngao dầu ương ở mật độ 15 ấu trùng/ml đạt kích cỡ 193,7 ± 1,2 µm và tốc độ tăng trưởng đặc trưng đạt 4,7 ± 0,1%/ngày, cao hơn ở mật độ 20 và 25 ấu trùng/ml (p <
0,05), nhưng sai khác không có ý nghĩa so với ấu trùng ương ở mật độ 10 ấu trùng/ml (202,3 ± 3,5 µm và 5,3 ± 0,2%/ngày). Thời gian ấu trùng biến thái, chuyển xuống đáy tại ngày thứ 4 ở nghiệm thức mật độ 10 và 15 ấu trùng/ml, trong khi ở mật độ 20 ấu trùng/ml là ngày thứ 5 và 25 ấu trùng/ml là ngày thứ 6. Tỷ lệ sống của ấu trùng cao nhất ở nghiệm thức 10 ấu trùng/ml, đạt 80,7 ± 0,1%, sai khác có ý nghĩa so với ấu trùng ở nghiệm thức 20 ấu trùng/ml và 25 ấu trùng/ml (p <
0,05), nhưng sai khác không có ý nghĩa (p >
0,05) so với ấu trùng ương ở 15 ấu trùng/ml (79,7 ± 0,2%). Kết quả nghiên cứu cho thấy, mật độ ương 15 ấu trùng/ml là lựa chọn phù hợp nhất, cân bằng giữa hiệu quả sinh học và kinh tế trong ương ấu trùng ngao dầu từ giai đoạn bơi tự do đến giai đoạn sau biến thái.The study aims to determine the effect of stocking density on the growth and survival rate of clam (Meretrix meretrix) larvae from the D-veliger stage to the post metamorphosis stage (crawled larvae). The experiment was conducted with 4 larvae stocking densities such as: 10 larvae/ml, 15 larvae/ml, 20 larvae/ml, and 25 larvae/ml in 12 120 L plastic tanks, each treatment was repeated 3 times. The experiment was carried out in 7 days in June 2024 at the Research Center for Aquaculture Breeding and Services in Thanh Hoa, located in Hoang Thanh commune, Hoang Hoa district, Thanh Hoa province. Research results show that clam larvae at 10 larvae/ml treatment had 202.3 ± 3.5 μm length and 5.3 ± 0.2%/day of specific growth rate (SGR) significantly higher than them reared at the densities of 20 and 25 larvae/ml (p <
0.05) but had not significant difference compared to larvae at density of 15 larvae/ml (193.7 ± 1.2 μm length and 4,7 ± 0,1%/day. The time for the larvae to reach the bottom at the densities of 10 and 15 larvae/ml tanks on day 4, while larvae reared at density of 20 larvae/ml on day 5 and 25 larvae/ml on day 6. The highest survival rate of clam larvae found at the stocking density of 10 larvae/ml (80.7 ± 0.1%), significant difference compared to these larvae at densities of 20 and 25 larvae/ml (p <
0.05), but had not significant difference with larvae at density of 15 larvae/ml (79.7 ± 0.2%). The results of experiment indicates that the stocking density of 15 larvae/ml was suitable for rearing clam larvae from D-veliger to post metamorphosis stage.

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