Non-specific cellular defence mechanisms of rainbow trout (Oncorhynchus mykiss) in intensive and extensive rearing technologies

Abstract

Listen

Translate article

Water as a habitat is highly variable in terms of the physico-chemical properties. The aim of the studies was to analyze the quality of the technology by evaluating the non-specific cellular defence potential of rainbow trout (Oncorhynchus mykiss) in diversified intensity culture systems and in different periods of the breeding cycle. The evaluation was conducted in order to establish the scientific basis for the development of principles for recognition of the culture of this species as ‘organic’. Six rainbow trout rearing farms were selected for the studies and divided into two equal groups according to the production technology: farms with a flow through system (with single water usage – OOH) and facilities with multiple water usage via its backflow (re-circulating system – RAS). The samples for tests were taken from 20 individuals from each fish farm. In all fish that originated both from OOH-type farms and RAS operations, an increase in the activity of non-specific cellular immunity in the autumn was observed. Statistically significant reduction in the activity of cellular defensive mechanisms in small (300–500 g) and big (501–850 g) fish occurred on two 3-OOH and 3-RAS farms in spring and autumn in 2011. During these periods, the research has shown the presence of Infectious Pancreatic Necrosis Virus (IPNV), which provoked an immune suppression. Based on the obtained results it is concluded that there were no significant differences in the parameters of non-specific cellular immunity in rainbow trout originating from different farming systems OOH and RAS.