Effect of graded levels of Aquapro® herbal stimulant on growth and intestinal morphology in dusky kob, Argyrosomus japonicus (Temminck & Schlegel, 1843)

Abstract

This study was designed to test the effect of a herbal product, Aquapro®, on the growth performance and gut morphology of dusky kob, Argyrosomus japonicus (Temminck & Schlegel, 1843) in a 49-day feeding trial. Four diets, containing Aquapro® at 0 (Aqua0), 50 (Aqua50), 100 (Aqua100), and 150 (Aqua150) g.kg-1 dry matter (DM) were formulated. Forty-five fish (14.44 ± 0.27 g) were randomly distributed into each of 12 experimental tanks. Each dietary treatment was randomly allocated to three tanks and offered to fish at 2.8 % body weight. Ten fish from each tank were randomly sampled weekly for length and weight measurements. At termination, three fish from each tank were sampled for distal intestinal tissues for histology preparation. A non-significant (P > 0.05) interaction between the diets and the fish age (weeks) on both the weight and caudal length of the fish was observed. The fish weight decreased significantly with an increase in Aquapro® inclusion in the diets beyond 100 g.kg-1 . The Aqua150 diet produced the least weight gain of 24.57 ± 2.44 g. Aquapro® inclusion in the diets did not cause any gut morphological alterations in the fish. In conclusion, Aquapro® product, up to 100 g.kg-1 kob diet does not negatively affect juvenile dusky kob growth and all the tested inclusion levels did not cause gut inflammation, thereby suggesting uninterrupted nutrient absorption.