大黄鱼仔鱼微囊饲料粒度及水中稳定性评估

Evaluation on Microencapsulated Feed for Pseudosciaena Crocea Larvae Based on Particle Size and Stability of Granules in Water

大黄鱼仔稚鱼微囊饲料的粒度与水中稳定性是影响仔稚鱼净能量得益(netenegy gain)、育苗水质和培苗成活率的重要性状。本研究用激光粒度分布仪检测试制的(经SEM形貌鉴认为微胶囊型态的)大黄鱼仔鱼微囊饲料粒度分布、体积平均粒径和中位数粒径D_50的减小率和吸水率,评估其适口性与水中稳定性。参比12日龄时段大黄鱼仔鱼的口径,镜检全投喂微囊饲料的5日龄大黄鱼仔鱼的图像。结果表明,试制的4批次大黄鱼仔鱼微囊饲料的粒径尺度分布可基本符合大黄鱼仔鱼摄食要求。其中A2样品的D_50为71.63~61.92μm,浸泡海水120min的中位径减小率均值为10.97%;体积平均径减小率均值为14.19%。表明A2样品的水中稳定性可满足大黄鱼仔鱼阶段投饵操作要求。同时表明用湿法激光粒度分布仪检测微胶囊饲料的粒度与水中稳定性的步骤便捷,数据稳定直观,可作为检测渔用微胶囊饲料的粒度与水中稳定性的备选方法。

Particle size and stability in water of a microencapsulated feeding material for larvae and juveniles of Pseudosciaena crocea were studied in relation to the net energy gain of the fish,the water quality of the aquaculture pond,and the survival rate of the young seedlings.Size distribution and reductions on average volume and median diameter,D 50,of the particles after submerging in seawater were used to evaluate the suitability for fish feeding and the granule stability of feed.A laser particle size analyzer was applied for the measurement of 4 microencapsulated feed granules,which had been verified to be microcapsules by SEM morphology.The body size of 12-day-old yellow croaker larvae and the microscopic images of 5-day-old larvae fed on the microencapsulated silage were recorded for comparison.The particle size and size distribution of all four feed samples were found adequate for the feeding.In particular,Sample A2 had a D 50 of 71.63-61.92μm with a 12.15%volume reduction and 19.19%D 50 decrease after suspended in seawater for 120 min,indicating its potential in meeting the requirements for feeding larvae and juveniles of P.crocea.Furthermore,the wet laser particle size analyzer was considered adequate for measuring the particle size and size distribution as well as predicting the stability of microencapsulated granules in water.