Performance of the black tiger prawn (Penaeus Monodon) fed fucoidan under sub-optimal conditions

The Australian wild caught prawn sector has been in a state of steady decline in terms of tonnages and value over the past decade; while the aquaculture sector for prawns has been increasing over the same period. Prawn production within the aquaculture sector accounted for 6% of the total aquaculture production value for 2012-13. The industry does experience periods of extreme environmental conditions due to the geographic location where prawns are farmed, causing financial loses. These extreme conditions include high temperatures and heavy rainfall due to onset of the monsoonal season. Environmental stress caused by acute changes in temperature and salinity impact upon the immune system and aerobic metabolism of prawns, increasing susceptibility to disease, such as Gill-Associated Virus (GAV). Immunostimulants such as fucoidan and ˜í‚â§-glucan have shown potential to increase immune response and survival to diseases in penaeid prawns. Preliminary screening of commercially available fucoidan products were included in formulated feeds at 0.2 g.kgvÄv¢¬¨œÄ (Undaria pinnatifida [UP85 and F50], Fucus vesiculosus [FV90]) and 33 g.kgvÄv¢¬¨œÄ (Ascophyllum nodosum, MMB), and were fed to juvenile Penaeus monodon twice daily for 15 d to determine effects on growth performance, immune response and digestive gland (DG) histology. At the conclusion of the experiment the mean feed intake (FI), specific growth rate (SGR), weight gain (WG), feed efficiency ratio (FER) and survival were not different between feed treatments. Total haemocyte count (THC) and phenoloxidase activity (PO activity) did not increased in P. monodon fed fucoidan, although prawns fed the FV90 had increased granular haemocyte count (GHC) compared to prawns fed F50. DGs presented as tightly packed tubules contained within the inter-connective tissue with star-shaped tubule lumens, indicative of healthy animals.