Digestibility & Waste

[MikeM]

Great stuff, Nancy. Wish my work was not keeping me so busy so I could delve into all the points. The one that stands out to me is the reliance on bacterial decomposition to explain the reduction in visible waste. Let's divide that into two parts.

First, to the extent there is improved metabolism of the food ingested such that ammonia and CO2 wastes produced directly by the fish are increased, I would agree that is a good thing. The CO2 will degas harmlessly and the ammonia will be degassed/nitrified in a decently filtered pond.

Second, to the extent the bacterial action is occurring outside the fish, I have doubts about the suggestion that this is beneficial. I may suffer from conventional thinking that it is better to eliminate solid wastes prior to bacterial decomposition.

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BTW, my post was not directed at Saki Hikari foods. It raises questions I've raised in occasional comments from time to time over the past couple of years before Saki Hikari was introduced. There are frequent comments about a food creating less visible waste and that it is therefore more digestible, and these comments often coincide with the on-start of feeding wheatgerm foods. The S-H ad simply triggered me to post on the subject. So far I have only seen positive comments on the food and have not used it myself. So, nobody should get the idea that I am criticizing it. [Let's not turn carp dung into another FIR debate, please!] I am interested in gaining a better understanding of food/nutrition/waste relationships in connection with maintenance of closed system ponds and koi husbandry. I hope lots of folks will share their knowledge.

[James P]

Mike, although koi can taste sweet, sour, bitter etc, they, like many animals smell the value of a meal fish. Ingestion of feces is only likely if the koi smells protein in the feces. This then, by definition, suggests that the meal was originally only partially digested. This is the same reason a dog will take cat feces from a litter box and ingest it- they smell the protein remaining from a rich protein cat food that is not entirely absorbed in the gut and passes through.

Koi complicate this reality of rich food by being cold blooded. The feed back mechanism in a closed system is a huge influence. Koi eat rich food while out of the ideal temperature range and large amounts of feces are produced. Just try feeding Hikari higrowth in temps below 68 F. The water will deteriorate before your eyes! Feed the same at 74 F and the water is clear and the vortex is not so loaded.



The obviously dynamics of this feedback involves a drop in oxygen levels and a declining trend line in ORP as the bacteria count in the water rises. This in turn affects diffusion rates and efficiency at the level of the gill. Soon appetites decline for a number of primary and secondary affects.

[tewa]

hi nancy

i gather you work for hikari. I am quite sure sakai of hiroshima use their own food and so do momotaro

regards
tewa

[Nancy M.]

Quote: Originally Posted by MikeM Great stuff, Nancy. Wish my work was not keeping me so busy so I could delve into all the points. The one that stands out to me is the reliance on bacterial decomposition to explain the reduction in visible waste. Let's divide that into two parts. First, to the extent there is improved metabolism of the food ingested such that ammonia and CO2 wastes produced directly by the fish are increased, I would agree that is a good thing. The CO2 will degas harmlessly and the ammonia will be degassed/nitrified in a decently filtered pond. Second, to the extent the bacterial action is occurring outside the fish, I have doubts about the suggestion that this is beneficial. I may suffer from conventional thinking that it is better to eliminate solid wastes prior to bacterial decomposition. ------------- BTW, my post was not directed at Saki Hikari foods. It raises questions I've raised in occasional comments from time to time over the past couple of years before Saki Hikari was introduced. There are frequent comments about a food creating less visible waste and that it is therefore more digestible, and these comments often coincide with the on-start of feeding wheatgerm foods. The S-H ad simply triggered me to post on the subject. So far I have only seen positive comments on the food and have not used it myself. So, nobody should get the idea that I am criticizing it. [Let's not turn carp dung into another FIR debate, please!] I am interested in gaining a better understanding of food/nutrition/waste relationships in connection with maintenance of closed system ponds and koi husbandry. I hope lots of folks will share their knowledge.

Hi Mike
I got this info for myself, I did not understand the process either. We are all here to learn. That is why I had my friend get this info for me. I just hope this help others understand the whole relationship of food and waste a little better.
And thank you JR for adding to it... I think I finally get it...