Effect of Lemon Verbena,Aloysia triphylla, Extractin Dietary on Growth Performance, Proximate Composition and some Liver Enzymes of Rainbow trout Juveniles, Oncorhynchus mykiss.

Inroduction & Objective: The use of natural-origin growth stimulants due to the lack of destructive
environmental impacts has been considered in the past years. Hence this study was conducted to evaluate the
effect of lemon verbena, Aloysia triphylla, extract on growth performance, proximate body compositions and
some liver enzymes of rainbow trout juveniles, Oncorhynchus mykiss. Rainbow trout (average weight 25.52 ± 1.31 g) were allocated into 4 groups and
were fed by different levels of plant extract (0, 2.5, 5 and 7 g per kg of diet) spread on commercial diet for 8
weeks. After cultivation, fish was weighted and proximate compositions include moisture, protein, lipid and
ash were analyzed. Also in order to measure liver enzyme like Aspartate aminotransferase (AST), alanine
aminotransferase (ALT) and alkaline phosphatase blood was taken. After feeding trial the data obtained was analyzed. Results showed that fish fed experimental
diets had significant deference (P<0.05) in weight gain, specific growth rates, feed efficiency and feed
conversion ratios compared to control. There was no significant difference among treatments in survival
(P>0.05). There were no significant difference (P>0.05) in moisture, crude protein, crude lipid and ash
content of rainbow trouts fed with diets containing various levels of plant extract. AST, ALT and alkaline
phosphatase did not have significant difference between treatments (P>0.05). Results clearly indicate that the addition of Aloysia triphylla extract up to 7 g per kg of diet is
advisable for rainbow trout because it improved the growth performance and did not have harmful effect on
liver enzymes.