The microsporidian Enterocytozoon hepatopenaei is not the cause of white feces syndrome in whiteleg shrimp Penaeus (Litopenaeus) vannamei.

Background: The microsporidian Enterocytozoon hepatopenaei was first described from Thailand in 2009 in farmed, indigenous giant tiger shrimp Penaeus (Penaeus) monodon. The natural reservoir for the parasite is still unknown. More recently, a microsporidian closely resembling it in morphology and tissue preference was found in Thai-farmed, exotic, whiteleg shrimp Penaeus (Litopenaeus) vannamei exhibiting white feces syndrome (WFS).

Growth, nonspecific immune characteristics, and survival upon challenge with Vibrio harveyi in Pacific white shrimp (Litopenaeus vannamei) raised on diets containing algal meal.

A 70-day growth trial was conducted with postlarvae 12 (PL12) Pacific white shrimp (Litopenaeus vannamei) to study the suitability of soybean meal and oil originating from a single-celled microorganism (thraustochytrid) as fishmeal and fish oil substitutes in practical diets for L. vannamei. The growth, survival rate and immune characteristics were evaluated.

Monodon baculovirus (MBV) infects the freshwater prawn Macrobrachium rosenbergii cultivated in Thailand.

Field specimens of post-larvae of the giant freshwater prawn (Macrobrachium rosenbergii) from Thailand showed hepatopancreatic tubule epithelial cells that contained central, eosinophilic inclusions within enlarged nuclei and marginated chromatin. These inclusions resembled those produced by some baculoviruses prior to formation of occlusion bodies that enclose virions in a polyhedrin protein matrix. By electron microscopy, the intranuclear inclusions contained bacilliform, enveloped virions (approximately 327+/-29nmx87+/-12nm) with evenly dense, linear nucleocapsids surrounded by trilaminar envelopes with lateral pockets containing nucleoproteinic filaments.

Parvo-like virus in the hepatopancreas of freshwater prawns Macrobrachium rosenbergii cultivated in Thailand.

A survey of cultivated giant freshwater prawns Macrobrachium rosenbergii from Thailand revealed the presence of unusual spherical to ovoid inclusions in nuclei of hepatopancreas tubule epithelial cells. These began as small eosinophilic inclusions that became more basophilic as they increased in size. They were present in both R-cells and E-cells but were largest and deeply basophilic only in the E-cells.

White tail disease of the giant freshwater prawn Macrobrachium rosenbergii in Thailand.

White tail disease (WTD) of the freshwater prawn Macrobrachium rosenbergii has recently been the cause of high mortalities in Thai prawn farms. The causative agents of this disease in other countries are M. rosenbergii nodavirus (MrNV) and extra small virus (XSV), which are usually detected using reverse transcriptase-polymerase chain reaction (RT-PCR) protocols.