Influences of supplemental methods of commercial probiotics on the growth and digestive enzyme activities of spotted scat Scatophagus argus fingerlings

Spotted scat Scatophagus argus has a high nutritional value and is among the most widely consumed fish species in Asia. This study was conducted to learn more about the solution for stimulating digestive enzyme synthesis with commercial probiotics. Three different methods of probiotic supplementations of Probai A (Bayer) (feeding - OR, feeding and environment - OE, environment - EN) and control treatment (no probiotic applied) - CT were performed in triplicates by using a completely randomization design method. The results showed no differences in growth performance and survival rates of spotted scat at the fingerling stage among the treatments (p > 0.05). The hepatosomatic index (HSI) and conditional factor did not depend on the probiotic supplementation methods (p > 0.05), but these values had a significant difference between experimental treatments compared to control treatments (p < 0.05). After 15–45 days, only amylase activity in the stomach was significantly higher than those of the control group (p < 0.05). Amylase activity in the intestine and trypsin activity in both the stomach and intestine of experimental treatments were significantly higher than those of the control treatment during 15–30 days (p < 0.05), and then no significant differences were found from day 30 to day 45 (p > 0.05). Our findings indicate that probiotic administration through feeding was the best way to increase the growth weight of spotted scat at the fingerling stage. Further research on the mechanism of stimulating digestive enzyme synthesis when probiotics are used in commercial fish seed production is required.