Effect of various sources of dietary additive on growth,body composition and serum chemistry of juvenile olive flounder (Paralichthys olivaceus)

Asia traditional herbal feed additives have often been shown to have beneficial effects on disease resistance, growth, feed conversion and protein conversion. There have been few studies on the use of these feed additives in olive flounder diets. The present study was designed to determine if there are benefits associated with the inclusion of any of these traditional herbal feed additives in olive flounder diets. One thousand two hundred sixty juvenile fish averaging 6.5 g were randomly distributed into 36, 180‐L flow‐through tanks. No additive was included into the control (Con) diet. The aqueous type of additives: 2.5% bamboo (BB), 0.25% Prunus mume (PM), 2.5% Artemisia capillaris (AC), 2.5% cinnamon (CC), 2.5% Cirtus junos (CJ), 0.25% Cudrania tricuspidata (CT) and 2.5% Ficus carica (FC), and the powder type of additives: 1% Houttuynia cordata (HC), 1% safflower (SF) and 1% sea tangle (ST) were included into the experimental diets. Finally, 0.1% emulsifying oil (EO) was included into the experimental diet. Feed efficiency ratio (FER) of fish fed the BB, CT and SF diets was higher than that of fish fed the FC and HC diets. Protein efficiency ratio (PER) of fish fed the BB and SF diets was higher than that of fish fed the AC, FC and HC diets. None of serum criteria of fish was affected by any of dietary additives. Dietary additives did not affect weight gain and serum chemistry of olive flounder, but 2.5% bamboo extract and 1% safflower powder was effective to improve FER and PER.