Much has been stated on how to inject Koi. Some feel that Intramuscular Injection (IM) is appropriate. Some feel that Intraperitoneal Injection (IP - injecting into the body cavity) is the preferred route of administration practiced around the world in aquaculture and then some feel that they would never inject their Koi.
The goals of this article are to assist the hobbyist and dealers on the differences between the location of the injection site and the proper technique for injecting. This is the result of extensive research, clinical trials and the techniques used in hundreds of millions of finfish every year.
One group of experts feel that intramuscular injection is not only the preferred route of administration but rather the only route of administration that should be attempted for a variety of reasons. Some of these stated reasons are the with IP injections, there is an unwarranted risk of perforating an organ . Another is that you should never attempt an IP injection without first anesthetizing the fish and that has its own risks to the fish, unlike an IM injection that may be accomplished without anesthesia. Some also feel that the uptake of the injected solution is just as efficacious with the IM route of administration, and it is easier to teach this technique without most of the risks involved in IP injections.
To this end, some noteworthy items should be considered. First, with the IP route of administration, it is obvious that an increased chance exists of perforating an organ because in an IM injection the needle is penetrating only muscle tissue and is removed from close proximity to the organs. This is where injection techniques becomes invaluable to the hobbyist and dealer and will be discussed later in this article.
Second, and undoubtedly the crux of the issue, mammalian musculature is vastly different from Koi musculature. Even in mammalians, it has been known for years that IM injections are not predictable in their action nor duration. In mammalians, muscle tissue assimilates the injected material at a different absorption rate in each individual with widely varying degrees of efficacy. It is very unpredictable, as stated in the literature produced by the drug companies in their package inserts. The same may be said for Koi. Also in mammalians when an IM injection is given, it is normal to inject deeply into the muscle bundle to prevent the injected material from escaping out the injection site, it is not possible to make a comparison in Koi.- firstly because of the differences in musculature and note having deep muscle bundles - and secondly. because Koi will contact their muscles and evacuate the injected material muc h more readily than mammalians, so absorption is even more variable in Koi than mammalians. And unlike mammalians, is a bacterin is injected into the musculature of fish, it will result in an extreme inflammatory response with a very slow clearance time of the bacteria from tissue. This inflammatory response within the muscle can result in granulomatous lesions (ulcerations) that can resolve itself by rupture through the skin layer, resulting in scar formation or infection.
So, having stated the above, et us move to the administration of an IP injection in Koi. Anesthesia prior to injection affords the following benefits. Immobilized fish are easier to inject with little change of organ damage to the fish or self injections should the fish struggle. Also, anesthetized fish will be less stressed during he injection procedure than if no anesthetic is used, Research has proven that increased stress levels result in the release of corticosteriods, which has a negative impact on immune response.
With the above concerns addressed, use the following procedures during he intraperitoneal injection of Koi.