Effect of Psidium guajava striped catfish (Pangasianodon hypophthalmus) fingerling

Abstract

The study aimed to evaluate the efficacy of Psidium guajava extract based experimental diets and salinity on oxidative stress of Pangasianodon hypophthalmus fingerlings. The study was carried out (i) the feeding experiment, fish were divided into two groups: one group was fed in diets without the extract (control), while the another group was fed with 0.2% P. guajava extract supplementation in diets for 42 days. The muscle, gills, liver, and brain samples for analyzing oxidative stress were collected at beginning of the experiment and on day 42. (ii) The challenge experiment, fish in the first experiment were exposed to different salinity levels (0, 10 and 20 ‰) for 14 days and were continuously fed with 0.2% P. guajava extract supplementation. The sampling period was implemented on day which reached the target salinity (day 0), day 7 and day 14 for analyzing oxidative stress. The activity of the enzymatic antioxidant defense such as CAT was analyzed in four tissues. LPO was analyzed in order to evaluate the effectiveness of antioxidant defense. On day 42, supplementation of P. guajava extract in diet could reduced LPO levels in gills and brain (p<0.05) and increased CAT activities especially in gills (p<0.05). In the challenge experiment, after being affected by salinity, LPO levels and CAT activities tend to increased and decreased respectively. The treatment supplemented with 0.2% P. guajava extract significantly reduced (p<0.05) LPO levels in gills on day 0, 7 and 14 compared to basal diet. After fish fed P. guajava extract supplementation in diets, CAT activities significantly increased in gills on day 0 and day 7 compared to basal diet. Fish exposed to salinity and supplemented with P. guajava extract reduced oxidative stress as evidenced by a lower concentration of lipid peroxidation and higher activities of catalase in liver compared to basal diet after 14 days of feeding. The results demonstrated that P. guajava extract might have a potentially as a promising feed additive in aquaculture by regulating oxidative stress balance and resistance to salinity changes in striped catfish.