Determination of the effect of yellow centaury oil (hypericum perforatum) as a feed additive in rainbow trout (oncorhyncus mykiss) vaccinated with lactococcus garvieae

The objectives of this study were: investigate the in vivo antimicrobial activity, preventing to disease (against fish pathogenic bacteria, Lactococcus garviae), effect to enhancing growth performance of the essential oil from (Hypericum perforatum) in rainbow trout (Oncorhynchus mykiss). Hypericum perforatum oil which in fish diets was tested for growth, survival (RPS), protection of rainbow trout against. Hypericum perforatum oil was added to the ingredients of tested diets to represent control, 0.0, 1.5ml/kg diet. Fish (average 15-20 g) was distributed to various treatments at a rate of 70 fish per 400 L aquarium and fed one of the experimental diets for 8 week as triplicate. Some groups of fish were vaccinated (i.p.) against Lactococcus garviae at the beginning of the experiment and fed the same diets as described above. Following 8 weeks after feeding, fish were infected with Lactococcus garviae and mortalities was recorded. The highest mortality rate was found in the control group with a rate of 52.50%. When the groups were compared in terms of RPS values, the highest (100%) bacterin and 1.5 ml / kg Hypericum perforatum It was observed that it was in groups fed with supplementary feed.