Please cite this article as Maghoul MA, Kermanshahi H, Majidzadeh-Heravi R & Javadmanesh A. 2020. Effects of Different Levels of Date Waste Vinegar in Diet and Water on Growth Performance, Gastrointestinal Tract Morphology, Ileal Microflora and Immune Response of Broilers. Poult. Sci. J. 8(2): 247-257. © 2020 PSJ. All Rights Reserved Poultry Science Journal ISSN: 2345-6604 (Print), 2345-6566 (Online) http://psj.gau.ac.ir DOI: 10.22069/psj.2020.18328.1622 Effects of Different Levels of Date Waste Vinegar in Diet and Water on Growth Performance, Gastrointestinal Tract Morphology, Ileal Microflora and Immune Response of Broilers Maghoul MA, Kermanshahi H, Majidzadeh-Heravi R & Javadmanesh A Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Poultry Science Journal 2020, 8(2): 247-255 Abstract Keywords Vinegar Immunity Acidifiers Broiler chicken Microbial count Gut morphology To investigate the effects of dietary supplementation with industrial vinegar (IV) and waste date vinegar (WDV) on growth performance, intestinal morphology, and immune response of broilers, five hundred Ross 308 chickens were randomly divided into 50 cages in a 42-day breeding period. The experiment consisted of ten treatments with five replications in each treatment including; control 1 (standard feed without WDV or IV), control 2 (control 1 + 2% water into the feed), 1, 2, and 3% of WDV and 2% industrial vinegar (IV) into the feed and 0.5, 1, and 1.5% of WDV and 1% industrial vinegar (IV) into the water. One chicken from each replicate was slaughtered on days 24 and 42 to investigate gastrointestinal tissue growth as well as intestinal morphology. The results showed that growth performance was not affected by treatments in any period. The height and width of the villus in the treatments containing 1% of WDV into the water and 2% of WDV into the feed increased with time compared to the control treatments. On day 42 of the experiment, the crypt depth was also higher in the treatment containing 1% of WDV into the feed compared to the other treatments. The ileal coliforms were also affected by WDV addition into the feed at 42 days of age compared to other groups (P < 0.05). The highest amount of IgM and IgG were found to levels of 2% and 1% of WDV into the diet, respectively (P < 0.05). However, SRBC, ND titter was not affected by treatments. Also, no difference was found between industrial vinegar in water or feed in most of the studied parameters. The results of this study showed that supplementation of the diet with WDV had a positive effect on intestinal morphology and immune system of broilers compared to industrial vinegar. Corresponding author Hassan Kermanshahi Kermansh@um.ac.ir Article history Received: August 2, 2020 Revised: October 9, 2020 Accepted: October 25, 2020 Introduction The importance of using agricultural wastes in animal diets can be tested from different aspects, which include the growing trend of the country's livestock population. This trend indicates the need to make optimum use of available feed capacity and economical savings in livestock and poultry production using agricultural waste as cheap and useful alternative sources. Organic acids as synthetic varieties are currently used in poultry feeds. They are expensive and most farmers do not have access to these acids. Researchers are working on organic products due to the inhibition of a vast range of drugs for animal production. Organic acids, have growth stimulating properties and antimicrobial effects and have shown a good alternative to antibiotics (Paul et al., 2007; Rasschaert et al., 2016). In recent years, several studies were focused on using probiotics (Awad et al., 2006) and organic acids (Gunal et al., 2006) in poultry diets, since they improve the intestinal tract function. It has been shown that yeast products contain beneficial nutrients such as peptides, oligosaccharides, flavorings, and aromatic substances that improve intestinal health against pathogens (Roto et al., 2015). Probiotic products can also reduce the population of pathogenic bacteria such as Escherichia coli and reduce the pH of the small intestine of poultry, which in turn bird