Studies on dietary supplements for the control of aeromonas hydrophila infection in rainbow trout (oncorhynchus mykiss, Walbaum)

Abstract

Three compounds, garlic (Allium sativum), ginger (Zingiber officinale) and lipopolysaccharide (LPS) were selected from an examination of ten dietary supplements based on their performance in enhancing protection and immunity in rainbow trout (Oncorhynchus mykiss, Walbaum) fingerlings, after challenge with Aeromonas hydrophila. Thus, dietary garlic at doses of 0.5 g and 1.0 g/100 g of feed resulted in mortalities of 4% (relative percent survival [RPS] = 91.75%), compared with 80% mortalities in the controls. Use of dietary ginger and LPS led to 0% mortality (RPS = 100%), compared with 85% in the controls. Growth, feed conversion ratio (FCR) and protein efficiency ratio (PER) were enhanced in all the experimental groups. The mode of action involved stimulation of non-specific immunity by proliferation of immune cells, enhancement of phagocytic, oxidative burst, lysozyme, antiprotease and bacteriocidal activities, and modulation of digestive enzymes.