The function and activity of microorganisms are the key factors in understanding the quality of the animal-rearing environment. The health of animals and fishes in husbandry and aquaculture, as well as in nature, depends primarily upon their inherent resistance to microbial invasion, and the biological equilibrium between competing beneficial and detrimental microorganisms at the animal interface as mediated by the environment. In fact, there are useful and harmful microbes in the natural environment which directly affect the growth of animals and fishes.
The methods for how to keep pathogenic microorganisms, mainly bacteria and viruses, away from animal rearing environments is one of the main concerns of people engaged in these industries. To this end, the use of artificial compound food containing antibiotics for sterilization; the filtration of water; ozonation; the use of ultraviolet light, are all commonly adopted techniques in these industries. People engaged in there tend to believe that these procedures can eventually eliminate all microbes in animal-rearing environments, and produce and maintain a nearly sterilized biotope there. However, with these treatments the occurrence of pathogenic microorganisms which cause animal disease cannot be permanently removed. For example, if the antibiotic kanamycine is added to seawater, bacterial numbers decrease for about two days, but eventually the numbers will recover to their original level in aquaculture. The same phenomena can be seen when seawater is sterilized by filtration, ozonation or ultraviolet light treatment. After such treatment certain species of bacteria grow very quickly because less antagonism among the bacterial populations is present. Furthermore, no one can anticipate what kind of bacterial species may grow in the vacant space produced by the above treatments. The
prawn aquaculture of Asia and South America in a large part has not yet recovered from its collapse because of virus infection. And also, many fish diseases are spreading through aquaculture facilities in most of the world.
In addition, antibiotics represses the growth of only bacteria but not viruses in general. In this situation, use of antibiotics promotes increasing the number of viruses because the antagonistic bacteria distribute numerously, which mainly decompose the virus outside membrane (capsid, envelopeetc.) and inactivate their infectious activities, decrease in number due to these drugs, which is one of the main reasons that virus diseases are increasing in the animal husbandry and aquaculture.
Although people who engage in animal husbandry and aquaculture have started to realize that antibiotics are less effective, almost no alternative method of controlling disease has been found. It is therefore essential that new methods should be adopted wherein the antagonism of certain microorganisms is used to repress other pathogenic microbes, bacteria, viruses and fungi, in the environment.
The antagonism among microbes is a naturally occurring phenomenon through which pathogens can be killed or reduced in number in the natural environment. This method, which is called biological control or biocontrol, is already familiar in the field of agriculture. For example, the famous bacterium,Bacillus thuringiensis, which infects pathogenic insects through the mouth and eventually kills them (Kerr, 1972 & 1980), is now commercially sold in Europe and North America where several thousands of tons are in use. These positive results have extended to further studies using virus, fungi and protozoa as biocontrol agents to eliminate pathogenic organisms. This approach in animal husbandry and aquaculture is adopted in our company.
Thus the activities of microorganisms seriously affect the growth, survival and production rates of animals and fishes.
The main purpose of the research section of our company will therefore be to show how to utilize microorganisms to promote animal and fish growth, while at the same time repressing the growth of pathogenic microorganisms. To this end the ecology of microorganisms is elucidated in datail, in order to provide an all encompassing understanding of their role in animal rearing biotope and agriculture field. Isolation, cultivation and identification methods for antagonistic bacteria against pathogens are also be shown; as are methods for how to construct experimental systems for detecting useful microorganisms for the growth of husbandry animals, prawn, crabs and finfish.
In short, this section of our company clarifies the role of microorganisms in husbandry, aquaculture and agriculture for increasing production of animals and fishes as well as vegetables.