North Idaho Koi Keepers

January 2011 Workshop
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Articles

Our thanks to Spike Cover for leading this two-day workshop.  Post Falls Library hosted our group for the gathering.

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KOI (Koi Organisation International), Acriflavin treatments, PCR Testing, Flowrates, Retrofiting - this was a heavy duty workshop!!!  Here is a bit of the information shared at the workshop - full articles have been provided to NIKK members for study.

Flow rates through our filters, do they matter?

(as they relate to ambient ammonia in the pond)

By Spike Cover, May of 2006

Summary

In answer to the question posed by the title, yes they matter. Ammonia is a toxin and can cause fish death. Chronic sublethal levels can result in growth suppression and increased susceptibility to disease. Flow rate through the bio-converters (filters) and feeding rate are the two main determinates of ambient ammonia in a clean pond. As the flow rate goes up, the ambient ammonia comes down and as the feeding rate goes up, so does the ambient ammonia. Big ponds reduce ammonia spikes, big filters allow for higher feeding rates and automatic feeders allow the ammonia produced to be "leveled" over the day. The pH and, to a lesser extent, the temperature of the water effect the fraction of unionized ammonia, the most toxic form of ammonia. Raising either raises toxic ammonia. A good rule of thumb is that it takes about 60 gpm thru adequate bio-converters (filters) to process the ammonia produced by feeding one pound of food per day. Increasing the flow rate through existing bio-converters (filters) will almost certainly improve water quality. See complete article below.

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PCR Testing

By Spike Cover

4-10-04

When a koi is suspected of having koi herpes virus, the most sensitive way to confirm or refute the suspicion is to have a PCR test done on a sample of the fish’s tissue (usually from the gills, liver and/or kidney).

So just what is a PCR test anyway? For this, we need some background basics before we get to the actual answer to this question.

Background:

The nucleus of each living cell contains long strands of DNA. DNA is deoxyribonucleic acid and resembles a long spiral ladder. The sides of the ladder are formed from sugar molecules.

The rungs of the ladder are formed from another group of molecules, the nucleotide bases.

There are four bases, adenine (A), thymine (T), cytosine (C) and guanine (G). Each rung is made from two of the bases, one base attached to each side of the ladder. The two bases then meet in the middle and weakly bind to each other. The bases will only make rungs with specific combinations. The A bases will only join with T and C bases will only join with G. Each side of the ladder caries a long chain of bases (A,T,G,C) that form the code needed to build the organism. Because the bases will only form specific pairs in the rungs, each side of the ladder can be used as a sort of copy of the other side. If one side has the sequence T-G-C-A-G you know that the other side must be A-C-G-T-C (A only pairs with T and G only pairs with C).

Each type of life has nucleotides within the strands of DNA that are in a unique sequence. If a sufficient portion of this unique sequence can be determined (called "sequencing"), that sequence can be used to identify a particular species. In 2000, Ron Hedrick and Orin Gilad from the University of California at Davis were able to isolate the koi herpesvirus ("KHV") and later to locate and sequence a unique portion of it’s DNA sufficient to be able to distinguish it from other DNA within the koi and that of other pathogens that invade koi. Since then, at least three other laboratories have developed tests for KHV that use similar methods.

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Selected comments regarding Koi/carp nutrition

By Richard Strange & Spike Cover

General observations

The cut-and-try methods that have traditionally been employed in the Koi community have identified many methods that produce satisfactory results. However other, more science-based, methods could very likely produce superior results. This has certainly been true in other areas, e.g., agriculture.

The domestication of common carp and rainbow trout has focused on attenuating the adrenal response which has provided for much less handling stress in the fish. Other characteristics have remained essentially unchanged. Koi are races or color variations of domesticated common carp. This means that experimental results (with the possible exception of experiments relating to coloration) for domestic common carp almost certainly apply to Koi (David 2010). This would include nutritional experiments relating to growth and health.

It’s not possible to discuss the whole subject of Koi/carp diets in a few short statements. However this brief information sheet should shed some light on a few aspects of the subject.

Specific to Koi/carp diets

A diet for Koi and carp should include the following:

Protein: >35% protein crude protein (30.5% digestible) (National Academy of Sciences 1993)

Fats: >1% linoleic acid, >1% linolenic acid (National Academy of Sciences 1993)

Carbohydrates, see paragraph directly below:

The nutritional value of carbohydrates varies among fish. Warm-water fish can use much greater amounts of dietary carbohydrate than cold-water and marine fish. No dietary requirement for carbohydrates has been demonstrated in fish; however, if carbohydrates are not provided in the diet, other compounds such as protein and lipids, are catabolized for energy and for the synthesis of various biologically important compounds usually derived from carbohydrates. Thus it is important to provide the appropriate concentration of carbohydrates in the diet of the fish species being cultured (National Academy of Sciences 1993).

Fats and carbohydrates have been shown to have what is termed "protein sparing" qualities. This is only true up to a point and there are balances which, if exceeded, can cause detrimental health effects, e.g., fatty or glycogen impacted liver. Thus, diets need to be formulated with consideration for the effects one component has on others within the diet. Experimentally, carp and Koi have been shown to live and grow on a wide range of carbohydrate from 5% to 50% of the diet (Takeuchi 1979). In low carbohydrate diets, necessary calories are provided by protein and fat. In production aquaculture,

carbohydrates are used to spare more expensive ingredients. The Koi hobbyist is less constrained by feed costs and may select the diet that provides the best overall health. Unfortunately, the research has not been conducted to determine the most healthful mix of feed ingredients for Koi.

Yamamoto et al. (2003) found that at higher water temperatures such as are typical of summer (~25ºC = 77ºF), carp preferred high-protein diets to either high-fat or high-carbohydrate diets and at moderate water temperature (~17ºC = 62.6ºF), carp show equal preference for high-protein and high-fat diets but did not prefer high-carbohydrate diets at either temperature.

Koi can digest food throughout a wide range of temperatures. This is because they have different groups of enzymes called isoemzymes that can digest food at many different temperatures (Hochachka & Somero 1971).

There is no scientific rationale for changing the carbohydrate composition of a Koi diet with seasons or temperature. This applies to the popular trend to feed food with increased carbohydrate content in the winter.

When reading an ingredients label, the carbohydrates can safely be assumed to be the unidentified portion of the formulation after subtracting the crude protein, crude fat, crude fiber, moisture and crude ash. If unspecified, fiber, moisture and ash can be approximated as equal to those in other similar foods.

For more detailed information, please consider:

o Professor Richard Strange’s course, "How and Why of Koi Nutrition," offered on the Koi Organisation International web site, course #520, see: www.KoiOrgainisationInternational.org, and

o Chris Neaves also has a good basic course in Koi nutrition that can be found on the K.O.I. site, ref: course #204.

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References:

David, L. 2010. Personal communication with R. Strange. The communication included the following: "… koi are distinctive from European common carp and [the] reason for this is that they are more similar to the food carp strains from south-east Asia (where koi originated). Still you should remember that these are subtle differences as all these strains … belong to one species." L. David is the author of: Inheritance of colors and evolution of koi and carp, a study about genetic diversity of carp populations, inheritance of color traits in koi and evolution of the tetraploid genome of this species; publisher: VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG, Saarbrücken, Germany, 2009. Dr. David is also a geneticist and an Assistant Professor at the Department of Animal Sciences, Hebrew University of Jerusalem.

Hochachka, P & Somero, G 1971. Biochemical Adaptation to the Environment. pp. 99-156. In Hoar, W & Randall, D eds. Fish Physiology, Volume VI, Environmental Relations and Behavior. Academic Press, New York, NY.

National Academy of Sciences 1993. Nutrient Requirements of Fish. National Academy Press, Washington D.C.

Takeuchi, T. et al. 1979. Optimum Ratio of Dietary Energy to Protein for Carp. Bulletin of the Japanese Society of Fisheries, 45(8) 983-987

Yamamoto, T. et al, 2003. Effect of water temperature and short-term fasting on macronutrient self-selection by common carp (Cyprinus carpio). Aquaculture 656 220 (2003) 655–666

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