Judul: Immune system and production of pacific white leg shrimp on the different stocking density and sediment redox potential
Abstrak: Pacific white leg shrimp is a desirable species for shrimp farmers, which has eral advantages such as the availability of specific pathogen free post larvae, i relatively fast growth, and high survival rate. Pacific white leg shrimp Li 'P,enaeus vannamei has become one of the most important species in aquaculture sectors, including in Indonesia. Indonesian shrimp production had en dramatically increased during the last decade, from 191 148 MT in 2003 to 593 280 MT in 2014 or about 213% increase. The increase of shrimp production is ostly due to new openings of farming area and by intensification by increasing the stocking density. However, despite the progressive increase in production, shrimp-farming industry still encounters some major challenges among which is disease outbreak. Disease outbreak and environmental quality in shrimp culture systems are closely related. It has been suggested that viral and bacterial diseases, together with poor soil and water quality, were the main causes of the reported shrimp mass mortality in several studies. The aim of this study is to evaluate the effects of stocking density and sediment redox potential on the shrimp production performance and non-specific immune response. This study consisted of three main research stages with the following objectives: first, to observe the behavioural activity of L. vannamei and its oxygen consumption, as well as sediment oxygen demand in relation to sediment redox condition; second, to evaluate the effect of shrimp density on the animals immune system and growth performance, as well as the water quality in the culture system; and third, to evaluate the effects of sediment redox potential and shrimp stocking density on the sediment and water quality parameters, shrimp production performance, and immune response and resistance upon white spot syndiome virus (WSSV) challenge The first experiment was conducted in semi outdoor laboratory using 18 units of aquarium with a dimension of 30 cm x 30 cm x 100 cm. Each aquarium was filled with filtered seawater and 5 cm deep soil substrate with different redox pote tial at the bottom of each tank. Shrimp were randomly distributed into the tank at a stocking density of 130 shrimps m·²• One hour after being transferred to the aguarium, the shrimp swimming behaviour was observed for 6 consecutive hours, during which no feed was given to the shrimp. At the initial and end of expe ·ment, dissolved oxygen was measured at different depth. The study showed that sediment redox potential did not influence L. vannamei behavioural profile. Shrimp stayed on the tank bottom for most of the time in all treatments and these demonstrate that these animals were unable to stay for a long time in the water co , . Dissolved oxygen decreased with the increase of the water depth incHcating that dissolved oxygen on the bottom was consumed by both shrimp and s i; ent with the more negative sediment redox potential the higher sediment en demand. In the second experiment, a completely randomized experimental design was applied with four different stocking densities, i.e. 50, 150, 300 and 600 shr· s m·2 with four repetitions. Eighteen units of
Keyword: Stocking, White leg shrimp, Sediment redox