A Practical Guide to Nutrition, Feeds, and ... - cop.eXtension.org

determine with fish than with terrestrial animals,
because nutrients can be lost to the water from the feed
or from fecal material collected from the water.
Although determining digestibility coefficients is problematic
with fish, they have been determined for
commonly used feed ingredients for catfish (Tables
1–3).
Protein digestibility coefficients for feedstuffs
(Table 1) are generally used in formulating feeds, but a
more precise feed formulation can be derived if one
uses amino acid availability (Table 2) as the basis for
formulating feeds rather than digestible protein. For
example, the protein digestibility of cottonseed meal to
catfish is about 84%, but the lysine availability is only
about 66%. If feeds are formulated on a protein basis
using cottonseed meal, a lysine deficiency may result.
The major problem in formulating catfish feeds on an
available amino acid basis is the lack of sufficient data.
2 A Practical Guide to Nutrition, Feeds, and Feeding of Catfish
Digestion coefficients for energy, lipid, and carbohydrate
(Table 1) have been determined for catfish.
Lipids are particularly good energy sources for catfish.
Starches are not digested as well as lipid by catfish, but
the digestibility of starch by warmwater fish is higher
than that of coldwater fish. The level of carbohydrate in
the diet appears to affect starch digestion. Starch and
dextrin digestion decreases as the dietary level
increases. The predominant sources of carbohydrate in
catfish feeds are grain products, which are 60–70%
digestible.
The availability of minerals from feedstuffs has not
been studied to any extent in catfish. Phosphorus availability
has been determined for various sources of
phosphorus to catfish (Table 3). Generally, phosphorus
from plant sources is only about 30–50% available to
catfish; phosphorus from animal sources is about
40–80% available.
Table 1. Average apparent digestibility (%) for protein, fat, carbohydrate,
and energy of various feedstuffs determined for catfish.
Feedstuffs International Protein Fat Carbohydrate Energy
feed number
Alfalfa meal (17% 1 ) 1-00-023 13 2 16 2
Blood meal (81%) 5-00-380 74 4
Corn grain (10%) 4-02-935 60 2 , 97 3 76 2 59-66 2 26 2 , 57 3
Corn grain (cooked) (10%) 66 2 96 2 62-78 2 59 2 , 79 3
Corn gluten meal (43%) 5-04-900 92 4
Cottonseed meal (41%) 5-01-621 81 2 , 83 3 81 2 17 2 56 2 , 80 3
Fish meal (anchovy) (65%) 5-01-985 90 2 97 2
Fish meal (menhaden) (61%) 5-02-009 87 2 , 85 3 , 70-86 4 85 2 , 92 3
Fish oil 97 2
Meat meal and bone meal (50%) 5-00-388 75 2 , 61 3 , 82 4 77 2 81 2 , 76 3
Peanut meal (49%) 5-03-650 74 3 , 86 4 76 3
Poultry by-product meal (61%) 5-04-798 65 4
Poultry feather meal (84%) 5-03-795 74 2 83 2 67 2
Rice bran (13%) 4-03-928 73 3 50 3
Rice mill feed (9%) 63 3 14 3
Soybean meal (44%) 5-04-604 77 2 81 2 56 2
Soybean meal (48%) 5-04-612 84 2 , 97 3 , 85 4 72 2
Wheat bran (16%) 4-05-190 82 2 56 2
Wheat grain (13%) 4-05-268 84 2 , 92 3 96 2 59 2 60 2 , 63 3
Wheat shorts (17%) 4-05-201 72 2
1Values in parentheses represent percentage crude protein.
2From Cruz, E.M., 1975, Determination of nutrient digestibility in various classes of natural and purified feed materials for channel catfish,
Ph.D. dissertation, Auburn University, Alabama,
3From Wilson, R.P. and W.E. Poe, 1985, Apparent digestible protein and energy coefficients of common feed ingredients for channel catfish,
Progressive Fish-Culturist 47:154-158.
4From Brown, P.B., R.J. Strange, and K.R. Robbins, 1985, Protein digestion coefficients for yearling channel catfish fed high protein feedstuffs,
Progressive Fish-Culturist 47:94-97.