University of Guilan Aquatic Animals Nutrition 2980-8499 9 2 2023 06 22 Effect of different levels of choline chloride on intestinal bacterial flora in rainbow trout (Oncorhynchus mykiss) fry Effect of different levels of choline chloride on intestinal bacterial flora in rainbow trout (Oncorhynchus mykiss) fry 1 8 7028 10.22124/janb.2023.24805.1209 FA Ali Hajibeglou Department of Aquaculture, Faculty of Fisheries and Environmental Sciences, University of Agricultural Sciences and Natural Resources, Gorgan, Golestan, Iran Abdolrahman Mokhmi Department of Aquaculture, Faculty of Fisheries and Environmental Sciences, University of Agricultural Sciences and Natural Resources, Gorgan, Golestan, Iran Abdolmajid Hajimoradlou Department of Aquaculture, Faculty of Fisheries and Environmental Sciences, University of Agricultural Sciences and Natural Resources, Gorgan, Golestan, Iran Hossein Rahmani Part Pishsaz Poya Company, Aq-Qala County, Golestan, Iran Journal Article 2023 04 04 The present study was designed and conducted to investigate the effects of varying levels of choline chloride on the microbial flora of the rainbow trout, <em>Oncorhynchus mykiss</em> fry. A total of 750 fish were fed with diets containing 0 (control), 250 (Cho₂₅₀), 500 (Cho₅₀₀), 1000 (Cho₁₀₀₀), and 2000 (Cho₂₀₀₀) mg of choline chloride per kg of feed for 90 days. The required feed was obtained from the 21 Bayza Company. The amount of microbial flora and final weight was significantly higher in the Cho₁₀₀₀ and Cho₂₀₀₀ than in the control group. The addition of choline to the diet effectively improved the microbial flora. The most suitable amount of choline chloride was between 1000 and 2000 mg/kg in the diet of rainbow trout. The present study was designed and conducted to investigate the effects of varying levels of choline chloride on the microbial flora of the rainbow trout, <em>Oncorhynchus mykiss</em> fry. A total of 750 fish were fed with diets containing 0 (control), 250 (Cho₂₅₀), 500 (Cho₅₀₀), 1000 (Cho₁₀₀₀), and 2000 (Cho₂₀₀₀) mg of choline chloride per kg of feed for 90 days. The required feed was obtained from the 21 Bayza Company. The amount of microbial flora and final weight was significantly higher in the Cho₁₀₀₀ and Cho₂₀₀₀ than in the control group. The addition of choline to the diet effectively improved the microbial flora. The most suitable amount of choline chloride was between 1000 and 2000 mg/kg in the diet of rainbow trout. https://janb.guilan.ac.ir/article_7028_3947ea31e888ed802e5be335c4f7e208.pdf