温度和pH对公子小丑鱼幼鱼消化酶活性的影响

研究了温度和pH 对人工养殖下的公子小丑鱼（Amphiprion ocellaris）幼鱼的胃、肝脏、肠道中蛋白酶、淀粉酶、脂肪酶活性的影响，并对各部位消化酶活性进行比较。结果表明，在胃、肝脏、肠道中均可以检测出蛋白酶、淀粉酶、脂肪酶的活性，其中蛋白酶活性顺序为胃跃肠道跃肝脏，淀粉酶活性顺序为肠道跃肝脏跃胃，脂肪酶活性顺序为肠道跃肝脏跃胃。胃、肝脏、前肠、中肠、后肠蛋白酶的最适pH 值分别为2.2、7.5、7.0、7.0 和8.0；淀粉酶肝脏的最适pH 值为6.0，其余部位均为7.0；脂肪酶肝脏的最适pH 值为7.0，其余部位均为7.5。胃、肝脏、肠道的蛋白酶最适温度均为40益；胃淀粉酶最适温度为40益，肝淀粉酶最适温度为35益，肠道淀粉酶最适温度为30益；胃、肝脏、肠道的脂肪酶的最适温度均为40益。

Morphological observation on eggs, sperms in artificialhybridization of Oreochromis niloticusSarotherodon melanotheron

Eggs of female Oreochromis niloticus and sperms of male Sarotherodon melanotheron were collected byabdominal squeezing of the broodstocks. The egg shape, size, color and accumulation of yolk granules at different maturedstages were analyzed by optical microscope and dissecting microscope techniques, the result showed that the immaturedeggs were oval-shaped and covered with small blood vessel; the matured eggs were pear-shaped, eggs diameter were 0.5~1.6 mm, they were coated with a transparent egg membrane and filled with large amounts of golden yellow yolk granules;the over-matured eggs had irregular shape, with some liquefied yolk granules. The sperms were observed by scanningelectron microscopy technique, normal sperms were composed with head, middle and tail piece, the head was a elongatedcone, long diameter was 1.82(0.35)m, wide diameter was 1.41(0.34)m; the middle film was short and cylindrical, longdiameter was 0.74(0.08)m, wide diameter was 0.16(0.06)m; the tail, single flagellum structured, was extremely long, was16.42(0.35)m. Three types of abnormal sperm including short-tailed, double headed and two-tailed, were also observed.The results could provide some basic dates to improve tilapia artificial hybridization techniques.