Effects of phyllanthus amarus extract on digestive enzymes activity and stress tolerance of striped catfish (Pangasianodon hypophthalmus) fingerling exposure to salinities

Abstract

The study was carried out to investigate the effects of Phyllanthus amarus extract supplementation in dietary on digestive enzymes activity of striped catfish fingerling Pangasianodon hypophthalmus exposure to salinities. The study was carried out with two experiments (i) in the experiment 1, fish was fed in herbal diets without the extract (control) and 0.5% extract from Phyllanthus amarus for 42 days. The intestine and stomach samples for analyzing digestive enzymes activities were collected at the beginning of the experiment (30 fish for total) and at day 42 (3 fish/tank). (ii) In the experiment 2, fish in experiment 1 were used for challenging in different salinities as 0‰, 10‰ and 20‰ for 14 days and were continuously fed with basal diet and 0.5% Phyllanthus amarus supplementation. The sampling period was implemented on day which reached the target salinity (day 0) day 7 and day 14 for analyzing stress indicator and digestive enzyme activities. After 42 days, in the first experiment, fish was fed 0.5% P. amarus extract had significantly higher (P<0.05) in the digestive enzyme trypsin and amylase activity in stomach when compared to control treatment. In the second experiment, the results found that the lowest value glucose concentration significantly reduced (P<0.05) in fish fed by 0.5% P. amarus extract at salinity 10 g/L. The findings indicated that supplementation 0.5% of P. amarus extract in fish diets had positive to effect on some digestive enzyme activities and beneficial to reducing the glucose level to limit stress when cultured striped catfish fingerling exposed to different salinities.