Effect of Feeding Rate and Diet Oil Source on Growth Performance and Feed Utilization of Rabbitfish (Siganus rivulatus) Fry

Abstract

1. <span style=font-size:11.0pt;color:black; mso-bidi-language:AR-EG>Abstract This study was conducted to determine the optimum feeding rate and evaluate the total replacement of fish oil as main source of fat by linseed oil from diet on growth performance and feed utilization of rabbitfish fry. This trial was factorial (3x2) and continued for 114 days. The average initial weight (W 1 ) of fry was 0.18 ± 0.012 g and the average initial length (L <span style=mso-fareast-font-family:+mn-ea; color:red;mso-bidi-language:AR-EG>2 ) was 2.76 cm ± 0.05 . This trial tested two factors, the feeding rate (5%, 7% and 9% of fish body weight) with two diets (36.44% CP) differed in oil source (diet A contained fish oil) and (diet B contained linseed oil). The stocking density was 40 fish per m 3 ; fry was fed twice daily at 9 am and 4 pm. The results cleared that, insignificant differences between the different of feeding rates which used in this trial regardless the diet oil source , on the other hand, the growth parameters values increased with increasing the feeding rate and the diet which contained fish oil was the best in the growth parameters compared with the other which contained linseed oil. The growth performance parameters were significantly affected by interaction between feeding rate and oil diet source. Whereas, the fish fed at the diet (A) with 9% feeding rate was obtained the highest final weight (W 2 ), Total Gain (TG), Relative Growth Rate (RGR), and Specific Growth Rate ( SGR) in all the treatments. The feed utilization parameters were significantly affected by the feeding rates regardless of diet oil source. The best Feed Conversion Ratio (FCR) was recorded by the fish fed at 5% feeding rate , the statistical analysis did not show any significant differences between the fish fed at the diet (A) and diet (B) in all the feed utilization parameters. Also, the interaction between feeding rate and diet oil source on feed utilization of rabbitfish fry appeared significant differences in all the treatments . The best FCR value was achieved with was fish fed on the diet (B) and (A) at feeding rate 5%. <span style=mso-fareast-font-family:+mn-ea;color:black;mso-themecolor: text1;mso-bidi-language:AR-EG> 2. <span style=font-size:11.0pt;color:black; mso-themecolor:text1>Keywords: Fish oil ; Feeding rate; Feed utilization ; Growth parameters ; Rabbitfish; Total replacement