A study of Protexin Probiotic Increasing Effect of Diet on Growth and Survival of Astacus leptodactylus

Probiotics as living microorganisms added as dietary supplements, which improve the health of host animal. Most recently, probiotics has been studied for enhanching growth rate and disease resistance in fish but study on the effects of probiotics on the growth performance of crayfish, especially on Astacus leptodactylus, are not very much. The research is conducted to assess the effect of different levels of probiotic of Protexin in Isonitrogenous and Isoenergetics diets on growth and survival of Astacus leptodactylus. Experimental diets were inclusive 0، 1 and 3 g/kg food. The test followed a Randomized complete design. Each treatment organized with 3 replicates and totally 9 rearing tanks involved. The period of test being planned 8 weeks and the test organism housed in fiber-glass tanks of 100 l capacity with flowing water and aeration in tanks are supplied. The mean initial size of animals was 23. 05 ± 0. 74 g. The results showed that with increment of probiotic level in experimental diets the indices of growth of Astacus leptodactylus concerning weight gain and specific growth rates being improved, as difference of diets without and 3 g/kg Protexin were significant (p<0. 05). Also, there was not significant differences in condition factor and survival rate of test animals fed with experimental diets (p>0. 05). The results indicated that probiotic protexin have the increase ability to influence on growth performance in Astacus leptodactylus and the best effective concentration is level of 3 gr probiotic per kg feed.