中国草鱼和泰国草鱼利用牧草作食饵的比较

A Comparison between Grass Carp(Ctenopharyngodon idella)and Puntius(Puntius gonionotus)Using Paragrass(Brachiaria mutica) as the Primary Feedstock￣①

通过对中国草鱼（Ｃｔｅｎｏｐｈａｒｙｎｇｏｄｏｎｉｄｅｌｌａ）和泰国草鱼（Ｐｕｎｔｉｕｓｇｏｎｉｏｎｏｔｕｓ）分别在常规的尼罗罗非鱼（Ｏｒｅｃｈｒｏｍｉｓ，ｎｉｌｏｔｉｃｕｓ）、鲤鱼（Ｃｙｐｒｉｎｕｓｃａｒｐｉｏ）和黑鱼（Ｃｈａｎｎａｓｔｒｉａｔａ）混养体系中养殖７个月，比较两者对牧草（Ｂｒａｃｈｉａｒｉａｍｕｔｉｃａ）的利用效果。试验结果表明，中国草鱼与泰国草鱼相比，无论是每尾体重，还是每尾体长、平均每尾日增重都有明显优势（Ｐ＜０．０５）．而且，放养３个月后，中国草鱼每尾体重和每尾日增重均极显著地优于泰国草鱼（Ｐ＜０．０１）．中国草鱼和泰国草鱼的年产量分别为２１８６ｋｇ／ｈｍ￣２，１２３３ｋｇ／ｈｍ￣２．中国草鱼的成活率比泰国草鱼低，两者分别为３８％和８６％。

Two herbivorous fish,grass carp (Ctenopharyngodon ldella)and puntius (Puntiusgonionotus) were compared on using paragrass(Brachiaria mutica) as the primary feedstock inseparated common polycuItures of Nile tilapia(Orecbromis,niloticus),common carp(Cyprinus car-pio)and snakehead(Channa striata)over a period of 7 months. At the end of the experiment,theincrease in the individual body weight of grass carp(337 g)was higher than that of puntius(83g) (P<0.05). The increase in the individual body length of grass carp(30. 1 cm) was longer thanthat of puntius (18. 6 cm)(P<0.05).The mean daily weight gain of grass carp which was 1.6g/fish, was higher than that of puntius which was only 0.4g/fish (P<0.051). Furthermore,the indi-vidual body weight and the individual daily weight gain of grass carp were superior to those of pun-tius after being stocked for 3 months(P< 0.01).The total net extrapolated yields per year ofgrass carp and puntius were 2 l86 and 1 233 kg/hm￣2,respectively. Grass carp had an extremely lowsurvival rate(38%)comparing to that of puntius(86%).These results suggested that grass carpare of much better performances than puntius on using paragrass as the primary feedstock in com-mon polyculture.