Effect of Dietary Inclusion of Green Tea (Camellia sinensis) Powder on Growth Performance, Feed Utilization and Body Composition in Rainbow Trout (Oncorhynchus mykiss)

This study was conducted to evaluate the effect of dietary inclusion of green tea powder on growth performance, feed utilization and body composition of rainbow trout. A total of 546 fish with an average body weight of 40.4±0.01 g were divided in the seven experimental treatments. The fish were fed with diets containing 0%(control), 0.25%(diet1), 0.5%(diet2), 1%(diet3), 2%(diet4), and 3%(diet5) of dried green tea (GT) powder containin 5.3±0.04% epigallocatechin gallate-3-gallate (EGCG), 1%(diet6) green tea dust (GTD) containing 6.5±0.07% EGCG for 60 days. Fish fed with diet 2 had higher weight gain, specific growth rate, apparent net protein retention, and protein efficiency ratio than other groups, and had a lower feed conversion ratio than other groups, but not significantly changed than control group (P>0.05). Crude lipid content of liver and fillet in fish fed experimental diets were significantly lower than of fish fed the control diet (P<0.05). These results showed that dietary supplementation of GT powder in trout feed promoted the growth performance and feed utilization, and also administration of 1% level of GTD and different doses of GT powder in the experimental diets showed lipid-lowering effects for rainbow trout.