The best food (lipids and protein) are the ones that most closely match those used (present in the) by the consuming i.e. predator fish. More later on some specifics.

The following is from Mark Griffin fish food phd

Griffin
Lunker

Registered: 31/03/07
Posts: 10
Loc: Pacific, MO Just depends on what warm water fish you are feeding and what results you desire. For instance, when grown at 80 F, fingerling Hybrid Striped Bass growth varied significantly, depending on both type and content of dietary protein and content of fat. Catfish formulations are plant based, while good trout/salmon formulations are animal based (preferably fish based). Strictly carnivorous fish do not do as well on plant-protein based diets. Below, diets are described in terms of Protein/fat, so a 40/10 is 40% protein and 10% fat (the OLD reliable trout diet).

36/8 (plant based)... 280% Weight Gain X
42/4 (plant based)....347% " 1.24X
35/10 (fish based)....432% " 1.54X
44/8 (fish based)....487% " 1.74X
55/15 (fish based)....650% " 2.32X**

It is important to note that all of these diets were high quality, they were just designed for different purposes and vary greatly in cost. For instance the 36/8 is designed for channel catfish fingerlings and the 55/15 is designed for Atlantic Salmon fingerlings. The 55/15 may cost 4 times as much as the plant based 36, so the economics are certainly arguable... just depends.

**Additionally, the ultra high growth on the 55/15 should be taken with a grain of salt as it resulted in obese fish (HSB very efficiently lay down dietary fat in their abdominal cavity), indeed the whole-body fat of HSB fed the 55/15 was 62% greater than that of the fish fed the 42/4.

Lets revisit this topic on LMB this fall as Bob Lusk is working on a trial this summer that should give us some more to discuss. Mark


Feather meal as a fish food protein source. There are two primary factors of protein quality for monogastrics (fish for this discussion) - 1) Amino Acid profile and 2) Amino Acid availability. The amino acid profile of feather looks pretty good if you look at the Total Sulfur Amino Acid content. It has a high content of cystine - a sulfur amino acid (SAA). SAAs can be limiting in monogastric diets and tend to be expensive to formulate into diets (they are relatively low in many inexpensive plant proteins). Unfortunately, the reason it is so high is because feather is a structural protein. The di-sulfide bonds between two cysteines make the protein very tough. This is what gives the keratins their structural rigidity - like our hair and fingernails. Unfortunately, this serves to make them very hard to digest. Therefore, as a rule, the availability is not so good. To increase the availability, feather meal is often hydrolyzed, this is an attempot to break down the disulfide bonds to increase availability. Shoe leather analyzes at 85% crude protein, but it is not digestible.

A word on protein sources.... Most protein sources are available in different qualities. This is particularly true for the expensive animal proteins - fish meal, poultry meals, blood meals, etc. Quality and freshness of the raw materials and the processing are factors that result in this variability. As examples:
A) Quality of Raw Materials: Meat meals are often priced on protein content - simply put, it is the ratio of bone (ash) to meat (protein). Bones (minerals, ash) are not as valuable as protein.
B) Freshness of Raw Materials: The US commercial fishing fleet for menhaden now has all refrigerated vessel storage.... the season is in over the summer, primarily in the Gulf of Mexico. Obviously, if it is not refrigerated....
c) Processing: Blood has a good amino acid profile. If it is drum-dried (essentially scorched on a extremely hot steel drum) it has poor availability and is a fairly poor ingredient. If it has been spray dried under low heat - it is an excellent ingredient.

High quality fish meal is the gold standard - it has the best Amino acid profile for fish (fish protein to grow fish protein)and is highly digestible. Further, it tastes great to fish (fish meal based diets are much more palatable to carnivorous fish) and it contains about 10% fish oil (high in omega 3 polyunsaturated fatty acids). Many other proteins can be used as long as they are formulated properly into an overall dietary amino acid profile.

Holler if you have questions. MEG

Last edited by ewest; 12/18/14 04:15 PM.