Growth and compensatory growth of juvenile Pangasius bocourti Sauvage, 1880 relative to ration

To investigate the growth and compensatory growth responses of juvenile Pangasius bocourti, a 16-week trial was conducted in 15 indoor tanks. Juvenile P. bocourti weighing a mean of 2 g were fed a diet (40% protein) at 5 different ration levels (4%, 6%, 8%, 10% and 12% of initial body weight) per day for 8 weeks (restricted-ration period) and then re-fed a diet (25% protein) at normal ration for another 8 weeks (normal-ration period). The average final weight, specific growth rate and feed conversion efficiency were directly measured. At the end of the restricted-ration period, significant differences were found in growth parameters, average final body weight and specific growth rate among the five groups of fish receiving different rations (p < 0.05). The relationship between specific growth rate in wet weight (SGRw, percentage per day) and ration level (RL, percentage per day) was an asymptotic curve described as SGRw = 1.6913 + 0.3505RL − 0.0146RL2. Feed conversion efficiency decreased significantly with increasing ration levels. At the end of the normal-ration period, there was no significant difference in final weight among the five groups which indicates complete compensation in the fish experiencing restricted feeding. There was an improvement in feed conversion efficiency in the juvenile P. bocourti, experiencing restricted feeding. Based on the above results, it may be concluded that a ration size of 8% of body weight per day is optimal for good growth and feed conversion efficiency of juvenile P.bocourti.