Effect of probiotic on the growth performance and survival of ornamental fish of oscar (Astronotus ocellatus)

This study was conducted to evaluate the effect of dietary supplementation of protexin on the growth and survival of oscar (Astronotus ocellatus) fry with average weight of 4.99±0.12 g, in a sixty-days period. This experiment was conducted in a Completely Random Design in four treatments and three replicates with 144 fry (12 fry in each aquarium). Experimental Probiotic was mixed in three levels of 0.15, 0.5 and 1 gr/kg dry food and were fed to fry. The control treatment, was fed on nonsupplemented ration. Feeding rate was on basis of 4 percent of body weight, 3 times during a day. Based on the findings, all three experimental treatments showed a significant increase (p<0.05) in the final mean weight, weight gain percent and specific growth rate (SGR) as opposed to those of in the control treatment. Among all the experimental treatments, the treatment with 0.15 gr probiotic per kg of feed showed the greatest difference by accounting for the highest final mean weight (35.07±1.19), weight gain percent (615.67±15.04) and specific growth rate (SGR)(3.27±0.10). The best feed conversion rate (FCR)(1.13±0.04) and feed coefficient efficiency (FCE)(88.07±2.99) were obtained in the treatment of 0.15 gr probiotic per kg feed which was significantly different from that of in the control(p<0.05), whereas the treatments of 0.5 and 1 gr probiotic per kg feed did not have a significant difference compared to the control(p>0.05).Also, the maximum survival percent(100%) was obtained from the treatment of 0.15 gr probiotic per kg feed. The results indicated that the ability of probiotic protexin to influence the increase the growth rate and survival in oscar fry is relatively high and the most effective concentration is the level of 0.15 gr probiotic per kg of feed.