Animal Probiotics - A live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance

Probiotics used Food or Feed additives, A live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance.

Introduction
Probiotics are live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut. They are also called "friendly bacteria" or "good bacteria." Probiotics are available to consumers mainly in the form of dietary supplements and foods. They can be used as complementary and alternative medicine (CAM)A group of diverse medical and health care systems, practices, and products that are not presently considered to be part of conventional medicine. Complementary medicine is used together with conventional medicine, and alternative medicine is used in place of conventional medicine..1 To find out more about topics and resources mentioned in this fact sheet, see "For More Information."

1CAM is a group of diverse medical and health care systems, practices, and products that are not presently considered to be part of conventional medicineMedicine as practiced by holders of M.D. (medical doctor) or D.O. (doctor of osteopathy) degrees and by their allied health professionals such as physical therapists, psychologists, and registered nurses.. Complementary medicine is used together with conventional medicine, and alternative medicine is used in place of conventional medicine. Some health care providers practice both CAM and conventional medicine.




What Probiotics Are
Experts have debated how to define probiotics. One widely used definition, developed by the World Health Organization and the Food and Agriculture Organization of the United Nations, is that probiotics are "live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host." (Microorganisms are tiny living organisms--such as bacteria, viruses, and yeasts--that can be seen only under a microscope.)

Probiotics are not the same thing as prebiotics--nondigestible food ingredients that selectively stimulate the growth and/or activity of beneficial microorganisms already in people's colons. When probiotics and prebiotics are mixed together, they form a synbiotic.

Probiotics are available in foods and dietary supplements (for example, capsules, tablets, and powders) and in some other forms as well. Examples of foods containing probiotics are yogurt, fermented and unfermented milk, miso, tempeh, and some juices and soy beverages. In probiotic foods and supplements, the bacteria may have been present originally or added during preparation.

Most probiotics are bacteria similar to those naturally found in people's guts, especially in those of breastfed infants (who have natural protection against many diseases). Most often, the bacteria come from two groups, Lactobacillus or Bifidobacterium. Within each group, there are different species (for example, Lactobacillus acidophilus and Bifidobacterium bifidus), and within each species, different strains (or varieties). A few common probiotics, such as Saccharomyces boulardii, are yeasts, which are different from bacteria.

Some probiotic foods date back to ancient times, such as fermented foods and cultured milk products. Interest in probiotics in general has been growing; Americans' spending on probiotic supplements, for example, nearly tripled from 1994 to 2003.

Uses for Health Purposes
There are several reasons that people are interested in probiotics for health purposes.

First, the world is full of microorganisms (including bacteria), and so are people's bodies--in and on the skin, in the gut, and in other orifices. Friendly bacteria are vital to proper development of the immune system, to protection against microorganisms that could cause disease, and to the digestion and absorption of food and nutrients. Each person's mix of bacteria varies. Interactions between a person and the microorganisms in his body, and among the microorganisms themselves, can be crucial to the person's health and well-being.

This bacterial "balancing act" can be thrown off in two major ways:

By antibiotics, when they kill friendly bacteria in the gut along with unfriendly bacteria. Some people use probiotics to try to offset side effects from antibiotics like gas, cramping, or diarrhea. Similarly, some use them to ease symptoms of lactose intolerance--a condition in which the gut lacks the enzyme needed to digest significant amounts of the major sugar in milk, and which also causes gastrointestinal symptoms.
"Unfriendly" microorganisms such as disease-causing bacteria, yeasts, fungi, and parasites can also upset the balance. Researchers are exploring whether probiotics could halt these unfriendly agents in the first place and/or suppress their growth and activity in conditions like:
Infectious diarrhea
Irritable bowel syndrome
Inflammatory bowel disease (e.g., ulcerative colitis and Crohn's disease)
Infection with Helicobacter pylori (H. pylori), a bacterium that causes most ulcers and many types of chronic stomach inflammation
Tooth decay and periodontal disease
Vaginal infections
Stomach and respiratory infections that children acquire in daycare
Skin infections

Another part of the interest in probiotics stems from the fact there are cells in the digestive tract connected with the immune system. One theory is that if you alter the microorganisms in a person's intestinal tract (as by introducing probiotic bacteria), you can affect the immune system's defenses.

Proposed Mechanisms of Beneficial and Detimental Effect of Probiotics

Table 1. Proposed Mechanisms of Beneficial and Detimental Effect of Probiotics

Response Proposed mechanisms Main site of action Beneficial Suppression of (1) production of antibacterial compounds S, SI harmful bacteria (2) competition for nutrients S, SI, LI (3) competition for colonization sites S, SI Microbial/host (1) production of enzymes which support S, SI metabolism digestion (e.g., lactase) (2) decreased production of ammonia, SI, LI amines or toxic enzymes (3) improved gut-wall function SI, LI Improved immune (1) increased antibody levels SI,(LI) response of host (2) increased macrophage activity SI,(LI) Detrimental Competition for (1) consumption of glucose S, SI nutrients with host (2) consumption of amino acids S, SI

S = stomach; SI = small intestine; LI = large intestine.Source : Data adapted according to Fuller (1989) and Impey and Mead (1989)

Table 2. Data Supporting the beneficial shifts in Microbial or Host Metabolism by feeding Lactic Acid Bacteria Probiotics⁽²⁾

Target host Probiotic Response Authors Pigs L. acidophilus Decreased serum Gilliland et al. (1985) cholesterol Calves L. acidophilus Formation of inhibitory Gilliland and Speck (1977) bile acids Pigs L. acidophilus Decreased amine Hill et al. (1970a) Humans production Goldin and Gorbach (1984) Humans L. acidophilus Decreased production of Goldin et al. (1980) carcinogenic Goldin and Gorbach N-compounds (1984a) Rats L. bulgaricus Hydrolytic enzymes Gravie et al. (1984) Chicks L. acidophilus which improve Champ et al. (1983) Pigs digestion Jonsson and Hemmingsson (1991) Pigs Lactobacillus sp. Increased activity of Collington et al.(1990) brush-border enzymes

Referrence

1. Fuller R. Probiotics : The scientific basis. London; Chapman&Hall, 1992.

2. Salminen S. and Wright A. Acid Bacteria New York; Marcel Dekker, Inc., 1993.