Effect of moulting and lunar rhythms on the lymphoid organ spheroid (LOS) cells of the black tiger prawn (Penaeus monodon)

Insight into the lymphoid organ of penaeid prawns: A review

“…However, if the first hypothesis occurs, the spheroid cells will persist and increase in number within the LO as the animal grew and aged, as a result of continued viral replication. In addition, there was a fluctuation in the number of spheroids and it was not related to the size and age of animals [8,57]. This suggested that the first supposition [9] was unlikely.…”

“…If the spheroid accumulated in the haemal sinuses during the life of the prawns, the area of the LOS should increase with the increase in the size of the animal [8]. However, the number of LOS cells oscillated during the life span of the prawns and there was no association between the number of LOS cells and prawn size or sex [8,57]. It seemed that there was a process leading to no accumulation i.e., removal of spheroids.…”

“…However, a decreased number of the normal tubules due to spheroid formation might be just a perception, because tubule Cnf, connective tissue fibre; Smc, stromal matrix cells [57]. dispersion occurred during spheroid formation.…”

“…Since many immunological factors of prawns are associated with moulting stages [17,62e65], then it was hypothesised that the spheroid cells might be disposed of during ecdysis, the actual shedding of old exoskeleton [8,23]. However, there was no statistically significant moulting effect on the ratio of spheroid to lymphoid organ total tissue (STT) [57].…”

“…Changes in the number of spheroids occurred during the lunar periodicity both in laboratory maintained and in farmed prawns [57]. The lunar related pattern on spheroid cells in laboratory-held animals implied that this effect was endogenous and hereditary, without environmental cues [66,67].…”