Gnotobiotic animal
Encyclopedia
A gnotobiotic animal is an animal in which only certain known strains of bacteria
and other microorganisms are present. Technically, the term also includes germ-free
animals, as the status of their microbial communities is also known. However, the term gnotobiotic is often incorrectly contrasted with germ-free.
Gnotobiotic animals (also 'gnotobiotes' or 'gnotobionts') are born in aseptic
conditions, which may include removal from the mother by Caesarean section
. Such animals are normally reared in a sterile or microbially-controlled laboratory environment, and they are only exposed to those microorganisms that the researchers wish to have present in the animal. These gnotobionts are used to study the symbiotic
relationships between an animal and one or more of the microorganisms that may inhabit its body. This technique is important for microbiologists because it allows them to study only a select few symbiotic interactions at a time (see Scientific control
), whereas animals that develop under normal conditions may quickly acquire a microbiota that includes hundreds or thousands of unique organisms.
Such animals may also be used in animal production, especially in the rearing of pigs. After the Caesarean birth, these animals are introduced to their natural microflora in a stepwise fashion. This avoids undesired infections and leads to faster growth.
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and other microorganisms are present. Technically, the term also includes germ-free
Germ-free animal
Germ-free animals are animals that have no microorganisms living in or on it. Such animals are raised within germ-free isolators in order to control their exposure to viral, bacterial or parasitic agents...
animals, as the status of their microbial communities is also known. However, the term gnotobiotic is often incorrectly contrasted with germ-free.
Gnotobiotic animals (also 'gnotobiotes' or 'gnotobionts') are born in aseptic
Aseptic technique
Aseptic technique refers to a procedure that is performed under sterile conditions. This includes medical and laboratory techniques, such as with microbiological cultures. It includes techniques like flame sterilization...
conditions, which may include removal from the mother by Caesarean section
Caesarean section
A Caesarean section, is a surgical procedure in which one or more incisions are made through a mother's abdomen and uterus to deliver one or more babies, or, rarely, to remove a dead fetus...
. Such animals are normally reared in a sterile or microbially-controlled laboratory environment, and they are only exposed to those microorganisms that the researchers wish to have present in the animal. These gnotobionts are used to study the symbiotic
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
relationships between an animal and one or more of the microorganisms that may inhabit its body. This technique is important for microbiologists because it allows them to study only a select few symbiotic interactions at a time (see Scientific control
Scientific control
Scientific control allows for comparisons of concepts. It is a part of the scientific method. Scientific control is often used in discussion of natural experiments. For instance, during drug testing, scientists will try to control two groups to keep them as identical and normal as possible, then...
), whereas animals that develop under normal conditions may quickly acquire a microbiota that includes hundreds or thousands of unique organisms.
Such animals may also be used in animal production, especially in the rearing of pigs. After the Caesarean birth, these animals are introduced to their natural microflora in a stepwise fashion. This avoids undesired infections and leads to faster growth.