NON-CLOTTING HAEMOLYMPH OF WSSV-INFECTED SHRIMP: IS IT A FACTOR IN INFECTION PROCESSES?
Abstract: White spot syndrome
virus is recognized as the most prominent pathogen of penaeid shrimp and has
been affecting this shrimp farming industry around the world. The virus may
reduce the shrimp’s immune response and alter enzymatic and biochemical
composition of tissues. Similar to other environmental stressed or other
pathogeninfected shrimp, in late stages of WSSV infection, shrimp will fail to
clot the haemolymph, so any minor injury will lead to increased haemolyph loss.
A series of experiments to determine the effect of non-clotting haemolymph on
WSSV infection were carried out in controlled facilities in Indonesia. The
preliminary test showed that normal clotting time was 13.3 seconds while
WSSV-injected shrimp mostly failed to clot their haemolymph 16 hours post
infection (hpi). Some other clinical signs such as abnormal swimming, red
discoloration, white spots and mortality were consistent with those observed by
previous studies. Three shrimp species: banana shrimp (P. merguiensis) 9 g ,
white leg shrimp (P. vannamei) 7 g and the tiger shrimp (P. monodon) 16.5 g
were water-borne-challenged with non-clotting, WSSV-infected haemolymph (NCH)
from tiger shrimp donor in duplicate tanks each with 12 shrimp. The control
were tiger shrimps fed with WSSV-infected tissue at the rate of 40% of
bodyweight (BW) and other tiger shrimps were used as negative controls fed with
commercial feed only. The study revealed that NCH dosages of 1.46%; 2.03%; and
2.06% (v/v) for each species were sufficient to infect and kill all shrimps in
less than two days compared to eight days for the shrimps fed on infected
tissue. The WSSV in non-clotted haemolymph eventuallyattaches into the living
tissues of healthy shrimp. This mode of infection is likely more difficult to
control by the ordinary fine mesh screening method.
Keywords: non-clotting-haemolymph;
WSSV; infectious; Penaeus monodon; P. merguiensis; P. vannamei
Author: Coco Kokarkin
Soetrisno
Journal Code: jpperikanangg090030