International Journal of Advanced Biological and Biomedical Research Available online at http:www.ijabbr.com Volume 9, Issue 2 (2021) pp. 181-189 DOI: 10.22034/ijabbr.2021.524089.1345 181 | Page Original Article The Effects of Probiotic, Prebiotic and Synbiotic on Growth Performance and Immune Responses of Broiler Chicks Challenged with Heat Stress by Multiattribute Decision-Making Method Ebrahim Babakhani*, Reza Rostamian Department of Agriculture Economic, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran *Corresponding Author E-mail: e.babakhani@qaemiau.ac.ir Received: 30 January 2021, Revised: 09 February 2021, Accepted: 23 March 2021 ABSTRACT Background: Heat stress (HS) has negative effects on economic parameters of the poultry industry. Different strategies such as nutritional additives are used to alleviate negative effects of HS. The use of multiattribute decision-making (MADM) could help to select the best additive for alleviating the effects of the HS. Thus, the present study was conducted to investigate the effects of probiotic, prebiotic and synbiotic on growth performance and immune responses of broiler chicks affected by HS via MADM method. Methods: Two-hundred and forty broiler chicks were randomly assigned into 4 treatments with 6 replications and 10 broiler chicks per replication. The birds were treated with probiotic, prebiotic, and synbiotic for 42 days. A group was considered as control and received only basal diet. Stress condition was induced from 21 to 42 days of age. Growth performance and humoral immunity were assessed, then calculated and analyzed by MADM method. Results: The results showed that dietary supplementation of probiotic, synbiotic, prebiotic and control had coefficients of 0.762, 0.702, 0.581 and 0.00, respectively. Dietary supplementation of probiotic, prebiotic and synbiotic had better effects compared with control group. Conclusions: Therefore, dietary supplementation of probiotic may have better efficiency compared with other additives based on the MADM. The use of probiotics can be suggested for improving growth and immunity under the HS condition in the poultry industry. Keywords: Probiotic, Prebiotic, Symbiotic, Heat stress, Multiattribute decision-making 1. Introduction Heat stress (HS) has negative effects on economic parameters in the poultry industry [1]. It is defined as a status in that animals cannot maintain their body temperature against thermal environment [2]. HS decreases growth performance and defaults immune responses in broiler chicks [1, 3, 4]. HS shows its negative effects on immune responses by the decrease in level of total circulating antibodies [5]. It also has adverse effects on the intestinal mucosa and microbiota of broiler chickens [6].