Effects of psidium guajava extract on digestive enzymes and stress resistance of striped catfish (Pangasianodon hypophthalmus) at the fingerling stage

Abstract

The study was carried out to evaluate the effects of Psidium guajava extract on selected enzymes and stress resistance of striped catfish (Pangasianodon hypophthalmus)fingerling. There were two experiments (i) the first experiment, fish was fed with basal diet (control) and extract of 0.2% Psidium guajava supplementation for 42 days. The intestine and stomach samples for analyzing digestive enzymes activities were collected at beginning of the experiment and at day 42. (ii) the second experiment, fish in the first experiment were used for challenge in different temperatures as 27°C, 31°C and 35°C for 14 days and were continuously fed with basal diet and 0.2% Psidium guajava supplementation. The sampling period was implemented on day which reached the target temperature, day 7 and day 14 for analyzing stress indicators and digestive enzyme activities. The results showed that after 42 days feeding with Psidium guajava, the digestive enzyme of fish increased and was not significant difference compared to control treatment. In second experiment, glucose concentration of the fish with Psidium guajava supplementation showed the lowest value (64.63 mg/100ml) at 35°C compared to at 27°C, 31°C treatments. In term of digestive enzyme, after 14 days with Psidium guajava supplementation, the activities of enzymes decreased and not significant different from control treatment. In conclusion, supplementation of 0.2% Psidium guajava extract in feed diet reduced the glucose level to limit stress and had positive to effect on some digestive activities.