Aqueous extract of Ocimum tenuiflorum decreases levels of blood glucose in induced hyperglycemic tilapia(Oreochromis niloticus)

Objective:To evaluate,in hyperglycemic tilapia[Oreochromis niloticus(O.niloticus)].the effect of this aqueous extract on blood glucose levels.Methods:The hyperglycemia in O.niloticus was induced by adding glucose to fish pond water.An aqueous extract of Ocimum tenuiflorum (O.tenuiflorum) was prepared by boiling fresh leaves and the doses of 0,40,80,200 and 400 mg per liter of pond water were tested.Results:The blood sugar concentration for tilapia with hyperglycemic induced was an average of 50%higher than the control group.The blood glucose levels in tilapia after the induction of hyperglycemia were higher than the control group for 90 min after the treatment.The treatment with the aqueous extract of O.tenuiflorum dropped the serum glucose level of hyperglycemic tilapia until it was similar to that of the control group and was dose dependent.Conclusions:The results indicated that O.tenuiflorum was endowed with anti-hyperglycemic activity.To our knowledge,this is the first report on the use of fish as a diabetes model to test natural extracts from plants.

几种天然生物防腐剂对生鲜罗非鱼片防腐效果研究

以细菌总数、TVB-N为指标,比较了生姜、大蒜、溶菌酶、乳酸链球菌素、茶多酚、ε-聚赖氨酸、鱼精蛋白、壳聚糖等8种天然生物防腐剂对生鲜罗非鱼片的防腐效果。结果表明,8种天然生物防腐剂对生鲜罗非鱼片均有一定防腐作用,最佳防腐浓度分别为:生姜体积分数20 mL/100 mL,大蒜60 mL/100 mL,溶菌酶质量分数0.5%,茶多酚0.6%,乳酸链球菌素1.0%,鱼精蛋白0.6%,壳聚糖1.2%,ε-聚赖氨酸0.6%。其中,生姜、大蒜和壳聚糖的防腐效果相对较好。

罗非鱼对低频声刺激的听觉行为

用行为定量解析法,对罗非鱼在低频区(100～1000Hz)由计算机分别以 1s和5s给声和撒声,用4个不同频率声为刺激,以速度、方向、间距和重心变化以及它们的个体间平均值作行为量,统计分析,研究罗非鱼的听觉反应行为。结果表明,罗非鱼对低频各频率声刺激皆有明显反应,其最敏感频率在 400Hz,与有关鱼类听觉文献以及有关罗非鱼电生理学研究结果一致。