Effect of dietary Yucca schidigera extract on growth,total ammonia–nitrogen excretion and haematological parameters of juvenile striped catfish Pangasianodon hypophthalmus

A feeding trial with striped catfish, Pangasianodon hypophthalmus was performed to determine the effect of Yucca schidigera in practical diet on the growth, feed utilization, body composition, total ammonia–nitrogen (TAN) excretion and haematological parameters. A diet with fish meal as the main protein source without yucca extract was used as the control diet (Diet 1). Four diets were formulated with 0.075 (Diet 2), 0.1 (Diet 3) and 0.15 (Diet 4)% of yucca extract respectively. Fifteen fish per tank (initial mean weight 1.78 ± 0.05 g) were randomly allocated to 15 fibreglass tanks (80‐L) connected to a freshwater closed recirculation system (temperature 29.7 ± 1.0°C). The experimental diets were tested in triplicates for 12 weeks. The specific growth rate of fish fed Diet 4 was significantly higher when compared with fish fed Diet 1. The growth of fish fed diets Diet 2 and Diet 3 were not significantly different compared with fish fed the Diet 1. Striped catfish fed Diet 4 had significantly lower feed conversion ratio compared with fish fed Diet 1 and Diet 2 (P < 0.05).The incorporation of high level Yucca schidigera extract in the diets reduced TAN compared with Diet 1. Dietary inclusion of Yucca extract levels did not significantly affect the biometric parameters or whole body proximate composition of the striped catfish (P > 0.05). The PCV (%) in fish significantly increased with high levels of Yucca inclusion (Diet 4) compared with control diet. Fish fed Diet 4 showed significantly higher haemoglobin levels than Diet 1 (P < 0.05). The results indicate that dietary inclusion of Yucca schidigera extract is promising as a feed additive that could improve growth performance and some haematological parameters and the best Yucca schidigera level was 0.15%.