Catfish farmers are able to feed a nutritionally complete diet that provides required levels of nutrients and energy in a readily digestible form. It is essential to provide a complete diet because catfish can synthesize only a small portion of the required nutrients and the quantity of nutrients from natural food organisms in the pond is relatively small. Forty nutrients have been identified as necessary for the normal metabolic function of channel catfish.
Based on current knowledge, a digestible energy to crude protein (DE/P) ratio of 8.5-10 kcal/gram is adequate for use in commercial catfish feeds. Ratios above this range may lead to increased fat deposition and if the energy ratio is too low, the fish will grow slowly.
Catfish feeds contain grain or grain by-products that are rich in starch. In addition to providing an inexpensive energy source, starch helps bind feed ingredients together and increases expansion of extruded feeds so that the feed pellets are water stable and float in the water. A typical catfish feed contains 25 percent or more of digestible carbohydrates.
Lipid levels in commercial catfish feeds rarely exceed 5-6 percent. About 3-4 percent of the lipid is inherent in the feed ingredients, with the remaining 1-2 percent being sprayed onto the finished pellets to reduce feed “fines”. Both vegetable and animal lipids have been used for pellet coating.
Considerable work has been conducted over the last 10 years concerning the level of dietary protein and amino acids needed for cost effective growth. Data from these studies indicate that the dietary protein requirement for various life stages of catfish ranges from about 25-50 percent. Recent studies have indicated that a protein level of 28 percent is adequate for growout when fish are fed to satiation.
Catfish feed are generally supplemented with a vitamin premix to meet dietary requirements and to compensate for losses due to feed manufacture and storage. Catfish feeds are also supplemented with phosphorus and a trace mineral premix. However, there is evidence that supplemental trace minerals may not be need in diets using animal proteins.
There are various types of catfish feeds. The type being used at any particular time is a function of size of fish being fed, whether the fish are feeding at the surface or in the water column, and if an antibiotic is incorporated.
Catfish fry in hatcheries are fed finely ground meal- or flour-type feeds containing 45-50 percent protein. Fines or crumbles from 28 or 32 percent protein feeds for food fish growout are suitable for fry stocked in nursery ponds until they reach 1-2 inches in length. Larger fingerlings should be fed small floating pellets (1/8 inch diameter) containing 35 percent protein. Advanced fingerlings (5-6 inches) and food fish are generally fed a floating feed of approximately 5/32 – 3/16 inch in diameter containing 28-32 percent protein. Some producers switch to a slow-sinking feed during the winter.
Antibiotics are administered to catfish through incorporation in feeds. Depending on the particular antibiotic chosen, the feed may either be floating or sinking.
Despite considerable research, feeding catfish is far from an exact science. It is a highly subjective process that differs among catfish farmers. The variation in feeding practices is a product of numerous factors such as cropping system, fish size, ability to manage water quality, experience of feeding labor, and difficulty in estimating fish inventory.
In general, fish should be fed once a day as much feed as they will consume without adversely affecting water quality. However, depending on water quality variables and the health of the fish, it may be advisable to restrict the daily feed allowance or to feed less often. Long-term feed allowance should not exceed 100-125 pounds per acre per day.
Most catfish producers feed once a day, 7 days a week during the warmer months. Although feeding twice a day may slightly improve growth of fingerlings, the logistics of multiple feedings on large catfish farms make it impractical.
Feed is typically blown onto the surface of the water using mechanical feeders. Feeds should be scattered over as wide an area as possible to provide equal feeding opportunities for as many fish as possible. Feeding with prevailing winds allows the feed to float across the pond and minimizes the amount of feed washing ashore. Overfeeding should be avoided since wasted feed increases production costs.