REDUCING THE ARTIFICIAL FOOD BY USING SAFE SANITATION ALTERNATIVES UNDER A POLYCULTURE SYSTEM

Ahmed F. Fath El-Bab

Central Laboratory for Aquaculture Research at Abbassa, Agriculture Research Center, Egypt.

Abstract

The present study was carried out to investigate the effect of treated poultry manure as safe organic matter (rigirs) at rate of 100kg/feddan weekly and artificial feed on growth, economic efficiency and pond productivity of Nile tilapia, Oreochromis niloticis and grey mullet, Mugil cephalus. Ten ponds (½ feddan) were stocked by Nile tilapia and grey mullet. Ten ponds (two replicates for each treatment) were designed for five treatments and stocked with Oreochromis niloticus (4500 fish/pond), grey mullet (1500 fish/pond). The experimental earthen ponds used in the study were treatment 1(control): artificial feeding throughout the experimental period (26 weeks), treatment 2: ponds fertilized by (rigirs) at rate of 50kg/ pond weekly for the first month of the experimental period, followed by pelleted artificial feed until the end of experiment, treatment 3: ponds fertilized by (rigirs) at rate of 50kg/ pond weekly for the first two months of the experimental period, followed by pelleted artificial feed until the end of experiment, treatment 4: ponds fertilized by (rigirs) at rate of 50kg/ pond weekly for the first three month of the experimental period, followed by artificial feed until end of experiment, and treatment 5: ponds fertilized by (rigirs) at rate of 50kg/ pond weekly during the whole experimental period (26 weeks). Results obtained are summarized in the following:

Growth parameters:

Nile tilapia (ON): Treatment 1 recorded the highest ranges of body weight (BW), body length (BL), daily weight gain (DWG) and specific growth rate (SGR),while treatment 3 recorded the highest ranges of condition factors (K).

Grey mullet (GM): Treatment 1 recorded the highest ranges of body weight (BW), body length (BL), daily weight gain (DWG) and specific growth rate (SGR),while treatment 2 recorded the highest ranges of condition factors (K).

Chemical composition:

Nile tilapia: treatment 1 recorded the highest ranges of fat and ash%, treatment 4 recorded the highest ranges of protein content. While, treatment 2 recorded the highest ranges of moiture.

Grey mullet: treatment 4 recorded the highest ranges of moiture and protein content. treatment 1 recorded the highest fat content, while treatment 2 recorded the highest ranges of ash%.

Economical evaluation, content of the obtaind results showed that, the use of rigir at the first three months of culture Nile tilapia and grey mullet at rate of 100 kg / feddan / week, after that use artificial feed containing 25% crude protein at rate of 3 % of total biomass of in earthen ponds could be recommended for producing Nile tilapia and grey mullet. From the economical point of view, this treatment showed the best ratio of returns to total costs.