Abstract
This experiment investigated the role of graded dietary levels of two probiotic strains (Bacillus toyonensis; BT and Bifidobacterium bifidum; BB) on the growth rate, carcass traits, physiological and histological aspects of growing Japanese quail. One thousand and three hundred sixty one-day-old un-sexed Japanese quail chicks were distributed randomly into ten groups. The 1st group served as a control and fed the basal diet without supplement while the 2nd, 3rd, 4th and 5th groups received the control diet supplemented with 0.05, 0.075, 0.10 and 0.125% BT, respectively. The 6th group fed the control diet plus 0.10% BB while the remaining groups (7th to 10th) received the basal diet incorporated with the previous levels of BT rich with 0.05% BB. Dietary supplementation of BT and/or BB increased body weight and gain; however, feed intake and feed conversion were not affected. Amylase activity was significantly elevated in 5th, 7th and 9th groups, while lipase activity was improved in all treatment groups except 3rd and 6th groups. Results obtained concluded that dietary supplementation of BT with or without BB is useful for performance, digestive enzyme activities, blood cholesterols, antioxidant status and ileal histomorphometry and microbiota of growing Japanese quail. (c) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).