Effect of organic fertilizer and different supplementary feeds on production of Nile tilapia (O. niloticus L. ) and silver carp (Hypophthalmichthys molitrix val.) in erthen ponds [electronic resource].

Includes reference.

This study has been carried out to investigate the growth performance and economic efficiency of Nile tilapia (Oreochromis niloticus L. ) and silver carp (Hypophthalmichthys molitrix val.) reared in polyculture earthen ponds as well as pond productivity affected by organic ferilizing and supplementary feeds inputs. Nile tilapia (Oreochromis niloticus) fry averaging 0.14 g in weight and silver carp (Hypophthalmichthys molitrix val.) fry averaging 1 g in weight were assigned randomly to three tested different supplementary feeds inputs. At the begining all treatments were fertilized with treated poultry manure (rigirs) at rate of 100kg/ feedan weekly. Three tested different supplementary feeds inputs were applied in the earthen ponds at the last four months. These were (T1) supplemented with fish rigirs at rate of 3% of body mass, (T2) commercial diet (25% protein) at rate of 3% of body mass. (T3) supplemented with 50% commercial diet plus 50% fish rigirs at rate of 3% of body mass. Six earthen ponds each measuring 20x50 m² were used in the experiment. Each treatment was performed in duplicate. All the ponds were stocked with 2500 tilapia plus 500 silver fish / pond (12000/feddan). The study extended 183 days. Results obtained can be summarized in the following: 1- The highest (P< 0.05) final body weight, gain and average daily gain (ADG), were recorded for Nile tilapia in fish group fed commercial diet (T2) Silver carp fish group in (T1) supplemented with fish rigirs at rate of 3% of body mass exihibted the highest (P> 0.05) final body wieght, gain, ADG and SGR. 2- With regard to economic efficiency the total cost of (T2) supplemented feeds (25% protein) at rate of 3% of body mass was higher than T1 and T3 but a net return of T1 was higher than T2 and T3. In conclusion the use of supplementry fish rigirs at rate of 3% of body mass in fish ponds culture at last four months after fertilization with rigir at rate of 100 kg/ fedd. weekly in the first two months could be recommended for Nile tilapia and silver carp with stocking density 12000/ feddan.

Summary in Arabic.

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