_____________________________________________________________________________________________________ *Corresponding author: E-mail: ruthofongo@gmail.com, ruthofongo@ndu.edu.ng; # ORCID ID: https://orcid.org/0000-0002-2156-5591 European Journal of Medicinal Plants 32(4): 38-49, 2021; Article no.EJMP.68808 ISSN: 2231-0894, NLM ID: 101583475 Qualitative and Quantitative Phytochemical Screening of Bitter and Neem Leaves and their Potential as Antimicrobial Growth Promoter in Poultry Feed Ruth T. S. Ofongo 1*# , Elijah I. Ohimain 2 and Eustace A. Iyayi 3 1 Department of Animal Science, Faculty of Agriculture, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria. 2 Veterinary and Agricultural Microbiology Research Unit, Department of Microbiology, Faculty of Science Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria. 3 Department of Animal Science, Faculty of Agriculture, University of Ibadan, Nigeria. Authors’ contributions This work was carried out in collaboration among all authors. Author RTSO designed the study, wrote the protocol, wrote the first draft managed the literature searches, author EIO performed the statistical analysis, managed the analysis of the study, reviewed the first and second draft. Author EAI conceptualized the study. All authors read and approved the final manuscript. Article Information DOI: 10.9734/EJMP/2021/v32i430383 Editor(s): (1) Dr. Naseem A. Qureshi, National Center of Complementary and Alternative Medicine, Saudi Arabia. (2) Prof. Marcello Iriti, Milan State University, Italy. Reviewers: (1) Venmathi Maran Balu Alagar, Universiti Malaysia Sabah Kota Kinabalu Sabah, Malaysia. (2) A. Vijaya Anand, Bharathiar University, India. Complete Peer review History: http://www.sdiarticle4.com/review-history/68808 Received 22 March 2021 Accepted 31 May 2021 Published 08 June 2021 ABSTRACT Gastrointestinal health challenges without in-feed antibiotics are a crucial concern to poultry farmers. Although, quite a few substitutes for antibiotics have emerged, phytogenics and antibiotic properties of medicinal plants cannot be overlooked with regard to control, good health and minimizing sub – clinical bacteria-induced infections by zoonotic enteropathogenic bacteria in poultry birds. Vernonia amygdalina (Bitter leaf) and Azadirachta indica (Neem) leaves were collected early in the morning and oven dried to 15% moisture content. The non-essential oil was obtained by cold maceration method using methanol. Appropriate methods were used for the Original Research Article