DIETARY ZINC REQUIREMENT OF COMMON CARP (CYPRINUS CARPIO) FRY

DIETARY ZINC REQUIREMENT OF COMMON CARP

(CYPRINUS CARPIO) FRY

Mohamed M. Zenhom

Fish Nutrition Department, Central Laboratory for Aquaculture Research, Agriculture Research Center, Ministry of Agriculture, Egypt

ABSTRACT

The present experiment was conducted to estimate the optimum requirement of dietary zinc (Zn) for Common carp, (Cyprinus carpio) fry with an average 1.0 ± 0.01g, by using purified diets (35% crude protein) supplemented with increasing zinc levels. The basal diet was supplemented with 5, 10, 15, 20, 25, 30 and 35 mg zinc sulfate mono hydrate/kg¹. The experiment was conducted in 21 aquariums with three replications per treatment, each aquarium supplied with well-aerated and dechlorinated tap water for 12 weeks.

The results revealed that the optimum fish live body weight
and weight gain, were obtained at Zn levels from 20–30 mg/kg¹ diet. While the optimum specific growth rate, condition factor
and
Survival rate were obtained at Zn levels from 15–30 mg/kg¹diet. Feed consumed was significantly (P < 0.05) higher with fish fed Zn from 20-30 mg/kg¹diet (P < 0.05). Feed conversion ratio (FCR), Feed efficiency ratio (FER) and Protein efficiency ratio (PER) were significantly (P < 0.05) improved with fish fed Zn levels from 10-30 mg/kg¹diet. Dry matter and crude protein of fish body increased significantly (P < 0.05) with increasing Zn up to 30 mg/kg¹diet. Body fat was decreased significantly (P < 0.05) with increased Zn level, while ash appear no significant different. Fish fed dietary Zn levels up to 25 mg/kg^_1 was significantly increased Ca, P and Fe contents (P < 0.05), Zinc concentration in whole fish body was positively correlated with Zn levels in the diet.

It could be concluded that the common carp fry require 15-30 mg Zn/kg^-1 dry diet to enhance the growth performance, feed utilization efficiency and body composition as well as minerals contents in fish muscle.

Key words:
Common carp, zinc requirement, growth performance, feed utilization and
minerals contents.