The leucogram as an indicator off marine-cultured rainbow trout, Oncorhynchus mykiss (Walbaum), health in The Netherlands

Abstract

During a longitudinal survey from June until October 1987 cytological blood parameters of smoltified marine cultured rainbow trout, Oncorhynchus mykiss (Walbaum), were monitored. In this period, the trout were exposed to environmental stress resulting in summer mortality. The statistical analyses showed that the observed summer mortality was preceeded by a shift in the relative abundance of different peripheral white blood cells (PWBCs), from lymphocytic to extremely granulocytic, which was mainly attributed to mature granulocytes. It was concluded that changes in relative abundance of PWBCs can predict health disturbances in marine‐cultured rainbow trout.

Blood values of young Brazilian catfish Pseudoplatystoma corruscans (Agassiz, 1829)

“…The relative abundance of the different peripheral blood cells showed a predominance of old lymphocytes which is consistent with that reported for other species (Boon et al, 1990b, Peutz et al, 1996, Schippers et al, 1994. The high percentage level of lymphocytes suggests that the fish were not stressed (Pickering, 1986).…”

“…Nevertheless, it is reasonable to assume that haematology will play an even more eminent role in fish health, as opposed to farm animal health, because of the impracticability of physically examining respiratory, circulatory, digestive or nervous systems of live fish. Moreover, in contrast to post-mortem studies, the fish do not have to be sacrificed (Peutz et al, 1996). Therefore the objectives of the present study are to describe the normal morphology of the cellular blood components and to establish values of a selected number of cellular and humoral blood parameters of the pintado, Pseudoplatystoma corruscans (Agassiz, 1829), which are lacking.…”