Evaluation of red seaweed Gracilaria arcuata as dietary ingredient in African catfish, Clarias gariepinus

The aim of this study was to evaluate the use of dried marine seaweed, Gracilaria arcuata for the first time as dietary ingredient in partial substitution of fishmeal on the growth performance, feed utilization and body composition of African catfish, Clarias gariepinus. Four experimental diets were formulated: D1 as a control group; D2; D3 and D4 which included 10%, 20% and 30% G. arcuata meal respectively. One hundred and eighty African catfish weighing 9.62 ± 0.42 g, (mean ± SE) was divided into four groups corresponding to the different feeding regimes. The final body weight of the fishes showed significant differences (P < 0.05) between the control (D1); D2 and other treated groups D3 and D4, with weights of 66.98, 59.60, 47.34 and 30.73 g recorded for D1, D2, D3 and D4, respectively. Significant differences (P < 0.05) were also evident in weight gain, specific growth rate, and feed utilization between treatment and control groups. However, no significant differences (P > 0.05) were observed between the control group and fishes fed D2 for all previous parameters. Protein productive value, protein efficiency ratio, daily dry feed intake and total feed intake were also significantly lower in fish fed with a diet containing G. arcuata than in the control group and D2 which contains 10% of G. arcuata. Overall, the results of the experiment revealed that African catfish fed a diet with G. arcuata included in 20% and 30% levels showed poorer growth and feed utilization than the control group and D2. However, the study recommended that C. gariepinus can accept this ingredient up to 10% in their diets. More defined experiments therefore seem to be necessary in order to determine the maximum level of this marine seaweed in diets with amino acid supplementation for African catfish.