By Dr Colin
Walker BSc, BVSc, MRCVS, MACVSc (Avian health)
Through evolution, bacteria and warm-blooded animals have closely
associated themselves to form a closed system for mutual benefit. Through trial
and error, over millennia, populations of bacteria have evolved that are
indigenous to their animal host. The animal host receives the benefits of aid in
the digestive process, manufacture of essential nutrients, protection against
other undesirable bacteria, assistance in control of water in the body and other
metabolic advantages. The bacteria in return receive temperatures favourable for
their growth, a constant supply of nutrients and essential substances in the
form of the body’s secretions. Because of the exact nature of this relationship,
there are bacterial populations that are the most favourable for the host
of this mutually beneficial relationship is profoundly influenced by the other.
When certain changes occur in the host, corresponding changes are reflected in
bacterial populations in the bowel. Bacterial changes may occur as a result of
stress, diet change, antibiotic therapy and other factors. Conversely, as the
resident bacterial population changes, there are subsequent changes in the
animal’s activity. These include alterations in the host’s ability to digest its
food and its ability to protect itself from bowel disease. The animal host then
has the problem of getting back to an ideal relationship with its normal
resident population of bacteria. Hopefully it can accomplish such a relationship
before subsequent challenges again upset the ideal state.
Where animals are not stressed, have an appropriate diet, are not
crowded, are not given drugs, do not contract infection or metabolic diseases
and live in a clean environment, an ideal level of intestinal bacterial
population may be maintained on a rather steady basis. In fact, no differences
are generally reported in numerous trials under these ideal conditions.
described above, however, do not fit the environment under which our pigeons
race. Even in the best lofts, under the best managers, birds are subjected to
various stresses. This means that disruption of the normal balance of intestinal
bacteria can be a common event. If an ideal state is maintained, there is
optimal utilization of nutrients and a resistance to harmful organisms. This has
been shown in numerous experiments.