YOLK ABSORPTION AND START OF FEEDING OF LARVAL GREEN CATFISH, MYSTUS NEMURUS (CUV. & VAL.)

Amornsakun, T., Chiayvareesajja, S., Hassan, A., Ambak, A., Ang Kok Jee

Abstract:

Larval green catfish were produced by induced spawning using extracted hormone (Buserelin and Domperidone) for hormone injection. Twenty newly-hatched larvae were sampled from the hatching tank at 2 hourly intervals for observation of yolk absorption. Newly-hatched larvae measure 4.66 +/- 0.27 mm in total length (mean +/- SD, n=20) with yolk sacs measuring 1186.00 +/- 250 micro m^3 in volume (mean +/- SD, n=20). The yolk sacs were completely absorbed within 72 hr after hatching at water temperature of 25-30 C.

From the start of feeding experiments, larvae were fed Moina at a density of 5-10 ind/ml. Twenty larvae were collected at random from the aquarium at 2 hourly intervals. Some digestive tracts were fixed 52 hr after hatching at water temperature of 25-30 C, and contained Moina (225+/- 76.03 micro m, width) (mean +/- SD, n=20), at 1.8 ind/larvae, indicating that feeding had commenced.

(Fisheries Technology Programme, Department of Technology and Industries, Faculty of Science and Technology, Prince of Songkla University, Pattani Campus, Pattani, Thailand 94000)

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