The effect of probiotics on digestive enzyme activity during larvae and juvenile stage of Yellow Fin Tuna (Thunnus albacares)

Abstract

Yellow fin tuna fry production technology is not successful yet. This was assumed related to the biological and physiological characteristics of the fish. The physiological approach to regulating digestion through probiotics is needs to be studied. The aim of this study was to examine the effect of probiotics bacterial strains of the enzymatic activity in digestion system for the larvae to juvenile stages of yellow fin tuna, Thunnus albacares. The experiment was initiated by culturing 3 probiotic isolates (Bacillus subtilis strain TA-1, Bacillus amyloliquefaciens strain TN-2, Bacillus subtilis strain TO-4) and apply to the larval rearing of yellow fin tuna. In the experiment the treatments applied were supplemented probiotics and without probiotic, each treatment was held with 2 replications. Fish samples were collected every day and analyze the gene expression profile associated with digestion enzyme synthesis by total RNA isolation and cDNA synthesis followed analysis of its by using the RT –qPCR method. The results showed that the growth response of T. albacares tuna larvae reared with probiotics tended to be faster (P<0.05) than the control (without probiotics). The supplementation of probiotic could improved the expressed digestibility of the target genes associated with enzymatic synthesized. Amylase enzymatic synthesized increase 200-1200 times in larvae 10 –17 Day After Hatch (DAH), while in the lipase enzymatic activity started with 13 DAH ( 25 time) and 16 – 21 DAH by 150-300 times. In trypsin the highest enzymatic activity was at 16 DAH, which was 200 times. While in control, the expression of enzymatic synthesis of amylase, lipase, and trypsin was relatively low.