Power feeding.

[neutrino]

IMO the true objective of power feeding, optimal growth AND optimal health is not best met by a feed as much as they can stand approach. There's always an optimum range for a particular stage of development (protein requirements in many species decreases with age), which can vary somewhat by type of fish. If you get to reading science and aquaculture literature, species after species has optimal feed and protein intake levels. Levels of fatty acids also have an effect. Exceeding the optimum range, whether protein, fatty acids, total feed levels, etc. actually decreases growth, decreases feed and protein utilization efficiency, and increases water pollution according to the studies I've found. A lot of these or similar studies also show unhealthy changes to liver fat composition above certain levels, so it's not just about growing them up as fast as possible, long term health should be considered imo.

A few examples:
Study of P. acei

Results suggest that inclusion of more than 35% protein in diets containing 10% crude lipid does not benefit juvenile yellow tail growth performance. Further, as TAN excretion and feed costs increased at protein levels beyond 35%, we recommend a diet containing 35% protein and 10% lipid for promoting good growth of juvenile yellow tail cichlids under the conditions used in the present trial.

"TAN" above is total ammonia/nitrogen excretion, higher with excessive protein levels.

Study of discus

Five levels of protein were evaluated (350, 400, 450, 500 and 550 g kg–1 diet) and each fed to four replicates. Growth rate increased significantly with protein level up to 500 g kg–1 diet and then decreased.

Just a 50 gram increase over high end of optimum decreased growth.

Study of cobia

Polynomial regression analysis revealed a weight gain peak at a dietary protein concentration of 44.5%, which is regarded as the most suitable level for maximum fish growth.

Test range was 36-60%.

Study of oreochromis

Maximum growth of young tilapia was obtained using the diet containing 30% protein. Feed conversion efficiency increased from 20% to 30% dietary protein, and thereafter decreased for diets containing 40% and 50% protein.

Article from an aquaculture resource on trout rearing:

Under most circumstances, fish need to be fed less than they will eat. Overfeeding will cause the fish to use the feed less efficiently and will not increase growth rates significantly.

 

[crush329]

What do you mean by power feeding when you only feed 2 or 3 times a day? When I focus on a spawn, they eat a good 5 times a day(from me and the auto feeder). If the fry/juvies were out in the wild I'm sure they would eat at least 5 times a day. To control the waste level a water change is done every other day(about 25%). Your problem is definately your water quality... 2 weeks is way too long if your wanting growth. No offense man, but the way your going about it is how I would purposely stunt a fishes growth. You asked a good question and got a lot of good responses... Now hopefully your fish will hit some growth spurts.

 

[Mythic Figment]

IMO the true objective of power feeding, optimal growth AND optimal health is not best met by a feed as much as they can stand approach. There's always an optimum range for a particular stage of development (protein requirements in many species decreases with age), which can vary somewhat by type of fish. If you get to reading science and aquaculture literature, species after species has optimal feed and protein intake levels. Levels of fatty acids also have an effect. Exceeding the optimum range, whether protein, fatty acids, total feed levels, etc. actually decreases growth, decreases feed and protein utilization efficiency, and increases water pollution according to the studies I've found. A lot of these or similar studies also show unhealthy changes to liver fat composition above certain levels, so it's not just about growing them up as fast as possible, long term health should be considered imo.

A few examples:
Study of P. acei
"TAN" above is total ammonia/nitrogen excretion, higher with excessive protein levels.

Study of discus
Just a 50 gram increase over high end of optimum decreased growth.

Study of cobia
Test range was 36-60%.

Study of oreochromis


Article from an aquaculture resource on trout rearing:

I love that you posted study information. I am too lazy for that. LOL


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