Growth performance of the giant freshwater prawn, Macrobrachium rosenbergii juvenile fed on a basal diet containing different zinc concentrations

الملخص EN

The main objectives of this study were to evaluate the effects of zinc on growth performance, survival, feed utilization and body composition of the giant freshwater prawn, Macrobrachium rosenbergii juvenile.

Eight diets were formulated with 0 (control), 10, 30, 50, 70, 90, 110 and 130 mg Zn kg-1 of diet as Zinc sulphate (ZnSo4.

7H2O).

Fish meal, soybean meal, bread flour and wheat meddling were used as an ingredient of the basal diet which contained 36.7 % crude protein and used as control diet without zinc supplementation.

Twenty post-larvae of Macrobrachium rosenbergii of mean length of 1.45 ± 0.01cm and weight of 0.022 ± 0.001g were stocked in each aquarium, set in triplicate groups.

The experiment continued for 12 weeks.

The results revealed that, the best growth performance and survival rate were obtained with groups of prawn fed diet supplemented with 70 mg Zn kg-1 diet.

Best feed conversion ratio (FCR), feed efficiency ratio (FER), protein efficiency ratio (PER) and feed intake were obtained with diet supplemented with 70 mg Zn kg-1 and 90 mg Zn kg-1 of diet as compared to 0 control, 10, 30, 50,110, and130 mg Zn kg-1 diet.

Whole body composition of moisture and protein did not differ significantly among treatments.

The highest lipid content was obtained with the groups of prawn fed 30 mg Zn kg-1 diet compared with the others.

Whole body ash increased significantly with the increasing of zinc level.

It could be concluded that diet supplemented with 70 mg Zn kg-1 of diet is the best Zn level for feeding of the giant freshwater prawn, Macrobrachium rosenbergii under the experimental condition.