fa تخصصي Special پژوهشي Research <span style="font-size:11pt"><span style="line-height:120%"><span style="font-family:Calibri,sans-serif"><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times="">This study was performed to evaluate the effects of feeding with Bactocell</span></span></span><a name="_Hlk104709223">^{<span dir="RTL" lang="AR-SA" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times="">&reg;</span></span></span>}</a><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""> (BA) on microbial flora and morphology of intestine, growth performance, and antioxidant defense<b> </b>in koi fish</span></span></span><span dir="RTL" lang="FA" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times="">.</span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""> 300 koi fish were divided into four groups with three replications. Groups included control group (basic diet, BD), T1 (0.02 g BA / kg BD), T2 (0.03 g BA / kg BD) and T3 (0.04 g BA / kg basal diet). The studied fish were fed these diets for 60 days. Sampling was performed at the end of the test to evaluate the growth performance, microbial flora and morphology of fish intestines. Also, the effect of probiotic on the plasma antioxidant indices was evaluated on days 0, 30, and 60. Based on the results, the highest growth rate of Lactobacillus colonies was observed in the T1 group (<i>p</i><0.05). The highest increase in length and width of the intestinal fold was reported in T1 (<i>p</i><0.05). The highest growth rate was recorded in T3 and then T2 and T1 compared to the control group (<i>p</i><0.05). The results also showed an increase in antioxidant defense<b> </b>and a decrease in oxidative stress in groups fed BA. The highest increase in SOD was reported in T1 (<i>p</i><0.05) while no significant difference was observed in plasma MDA level at the end of the experiment (<i>p</i>>0.05). Generally, the results showed the positive effects of feeding with BA on the growth performance and antioxidant defense<b> </b>of ornamental Koi fish. </span></span></span></span></span></span><br> &nbsp; Pediococcus acidilactici, Koi fish,SOD, MDA 95 110 http://injvr.com/browse.php?a_code=A-10-1-31&slc_lang=fa&sid=1 M. Alizadeh Barogh 10031947532846001416 10031947532846001416 No Department of Biology, Roodehen Branch, Islamic Azad University, Rodehen, Iran A. Mahmoodzadeh 10031947532846001417 10031947532846001417 No Department of Biology, Roodehen Branch, Islamic Azad University, Rodehen, Iran R. Kazempoor 10031947532846001418 10031947532846001418 Yes Department of Veterinary Hygine, SR.C., Islamic Azad University, Tehran - IRAN Sh. Alavinejad 10031947532846001419 10031947532846001419 No Department of Aquatic Health and Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran