Stress and Intestinal Flora

Abstract

The effects of crowding and heat stress on the intestinal flora, body-weight gains, and feed efficiencies of rats and chickens as well as the effects of the administration of probiotics on the animals under stress were introduced. Irrespective of the type of stress and host species, the change of intestinal flora caused by stress showed almost the common tendency: when the animal suffered stress, Staphylococcus, Streptococcus, Corynebacterium, and Enterobacteriaceae commonly increased; when the stress was more severe, sometimes Peptococcaceae, Bacteroidaceae, and Clostridium also increased or Lactobacillus reduced. Body-weight gains and feed efficiencies were markedly suppressed under these stress conditions. Administering Lactobacillus to a chicken under heat stress improved its hypoplasia while administration of Bifidobacterium improved the feed efficiency and intestinal flora. Acknowledgments. We thank R. Harasawa of the Department of Veterinary Microbiology, Faculty of Agriculture, Miyazaki University, and Y. Yoshitake of Toyo Jozo Co., Ltd., for cooperation with these investigations. We also thank A. Ozaki and T. Oowada of this Institute for their assistance in the care of the animals, and K. Sakamoto of Nippon Kayaku Co., Ltd., for his assistance in preparation of the manuscript. The supplying of Bifidobacterium probiotics from Dr. T. Kawashima, Morinaga Milk Industry Co., Ltd., is gratefully acknowleged. These works were supported by research grants from the Science and Technology Agency of the Japanese Government.