en aquaculture aquaculture پژوهشي Orginal research papers <span style="font-size:11pt"><span style="line-height:120%"><span style="tab-stops:right 42.55pt"><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 carried out to evaluate the effect of different </span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times="">cinnamon powder levels in low and high carbohydrate diets on growth performance, liver histological changes, and the liver enzyme activity of rainbow trout (<i>Oncorhynchus mykiss</i>) juveniles</span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times="">. For this purpose, 360 rainbow trout with an average initial weight 16.12&plusmn;1.33 (means&plusmn;SD) were fed six diets supplemented with Diet1 (200 g/kg carbohydrate), Diet2 (200 g/kg carbohydrate, 30 g/kg cinnamon), Diet3 (200 g/kg carbohydrate, 50 g/kg cinnamon), Diet4 (300 g/kg carbohydrate), Diet5 (300 g/kg carbohydrate, 30 g/kg cinnamon), and Diet6 (300 g/kg carbohydrate, 50 g/kg cinnamon) for 8 weeks The results showed that fish fed Diet2 (62.64) and Diet3 (63.17) had higher weight gain as compared with treatments without cinnamon (<i>p</i><0.05). </span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="layout-grid-mode:line">Alanine aminotransferase and alkaline phosphatase </span></span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times="">were influenced by the experimental diet and the highest values were observed in Diet3 and Diet6 treatments (<i>p</i><0.05), but the lowest content of </span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="layout-grid-mode:line">aspartate aminotransferase </span></span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times="">was observed in Diet3 and Diet6 treatments (<i>p</i><0.05). It is concluded that dietary cinnamon can improve growth performance and liver enzyme activity in fish fed a low-carbohydrate diet rather than a high one.</span></span></span></span></span></span></span> Rainbow Trout, Cinnamon, Liver histological, Practical diets 986 997 http://jifro.ir/browse.php?a_code=A-10-3722-3&slc_lang=en&sid=1 M. Ravardshiri mitra_ravardshiri@yahoo.com 100319475328460051174 100319475328460051174 No Department of Fisheries, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran S. Bahram s.bahram@qaemiau.ac.ir 100319475328460051175 100319475328460051175 Yes Department of Fisheries, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran S.R. Javadian Ro.javadian@gmail.com 100319475328460051176 100319475328460051176 No Department of Fisheries, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran M. Bahrekazemi m.bahrekazemi@qaemiau.ac 100319475328460051177 100319475328460051177 No Department of Fisheries, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran