Periodic Fertilization Using Urea and Chicken Manure as Source of Natural Productivity in a Biofloc System during the Nursery of Pacific White Shrimp Litopenaeus vannamei

抄録

The effect of periodic fertilization on natural productivity, growth and survival during the nursery of Litopenaeus vannamei under a zero water exchange set up was investigated. Nursery culture was carried out for 15 days in 2 m³ indoor concrete tanks with stocking density of one post larvae (PL)·liter^-1 using PL 16 shrimp. Urea and chicken manure were initially applied a week before stocking and added weekly to maintain green water condition. There was no significant difference in the phytoplankton densities and microbial flocs in the two treatments. The results demonstrated that the weekly periodic application of urea in a zero water exchange set up was not viable while fertilization using chicken manure improved feed conversion rate as well as shrimp survival and production.