November 1993

SRAC Publication No. 187

IISouthernRegionalAquacultureCenter

Channel Catfish Production

Impacts of Diet Composition and Feeding Practices

Channel catfish require adequateprotein in their diet for goodgrowth and weight gain. Withincertain limits, catfish grow fasteras the protein content of their dietis increased. But when more pro-tein is provided by the diet thanfish can use for growth, the excessis used inefficiently as a source ofenergy or is lost through excretion.

Because protein is the most expen-sive component in commercial fishfeeds, producers benefit by feed-ing diets that meet, but don’t ex-ceed, the protein requirements ofgrowing fish. Today, most catfishproducers feed 32 percent proteindiets. Reducing the protein con-tent further would reduce costs,but might also increase the bodyfat of fish. Because excess fat de-creases dress-out yield and poten-tial shelf-life of processed catfish,both researchers and producerswant to know how little proteincan be included in catfish dietswithout reducing product quality.

Past studies have indicated thatoptimal protein levels for channelcatfish diets are between 25 and 45percent. This high degree of vari-ability may result from environ-mental factors or managementdecisions that affect the efficiencywith which catfish use dietary pro-tein. Such variables include thesize or age of fish being fed, watertemperature, stock density, water

The Southern Regional AquacultureCenter has supported research to help de-termine the impacts of diet compositionon catfish growth and the quality of pro-cessed catfish products. These researchprojects focused on several types of pro-duction systems, but were not conductedon commercial installations. The resultspresented should help producers identifyways to modify-feeding managementpractices to improve production effi-ciency, This publication was compiled by]ames T. Davis, D.M. Gatlin, 111 andMax R. Alleger, based on research con-ducted at Auburn University and Ken-tucky State University. Details areavailable from the applicable publica-tions listed.

quality, feeding rate and feedingfrequency.

Catfish grow-out in ponds

Feeding fingerlings to market sizein intensively managed ponds isstandard for the catfish industry.However, two distinct approachesto feeding have developed. Manyproducers feed their fish as muchas they will eat every day. Re-searchers call this feeding to satia-tion. But some producers practicerestricted feeding. They feed fishless than the maximum amountthey would consume, especiallylate in the grow-out period. Re-stricted feeding requires lessskilled management than feedingto satiation, and may help main-tain water quality. Two studiescompared the dietary require-

Large areas require machine feeding to reach all parts of the pond.

Diet effects are apparent at the processing plant.

ments of catfish produced underthese different feeding methods.

At Kentucky State University,5,434 fingerlings (13 per pound)per acre were stocked into re-search ponds. The fish were fedonce or twice daily all they wouldconsume in 20 minutes of commer-cial-type diets that containedeither 34 or 38 percent protein.Aeration was provided when dis-solved oxygen was predicted tofall below 4.0 ppm. At the end of170 days the sampled fish weighedan average of 1 pound. Survivalaveraged 75 percent and food con-version ratio was 1.5:1. Results ofthis experiment indicated that nei-ther feeding frequency nor the pro-tein content of the diet affectedany production-related factors.

Intramuscular fat can be measured infillets.

Producers can save money andtime by feeding pond-raised cat-fish to market-size on a 34 percentprotein (or less) diet to satiationonce daily.

Researchers at Auburn Universitymeasured the effects of feedingcommercial-type diets containing24, 28, 32, 36 or 40 percent proteinto fingerlings in ponds. Fish werestocked at a density of 5,436 peracre and fed either on a restrictedbasis or to satiation. Fish fed to sa-tiation gained more weight thanthose fed on a restricted basis. Dif-ferences in protein content did notsignificantly affect weight gain orfeed consumption, although maxi-mum weight gain was achieved byfish fed the 24 percent protein diet.Results indicate that fingerlings inintensively-managed ponds do aswell on 24 percent protein diets ason higher protein feeds when fedto satiation. However, a higherprotein diet was needed for maxi-mum growth when feed was re-stricted to no more than 60 poundsper acre per day.

Let’s talk economics. The feedingstrategy that minimizes costs doesnot necessarily maximize fishgrowth. As a result, catfish produc-ers need to adopt a feeding pro-gram that results in optimaleconomic returns for their opera-tion.

Economic analyses of theseAuburn University studies wereconducted. Feeding the 26 percentprotein diet to satiation produced

Commercially processed catfish show lit-tle fat on recommended diets.

the highest net return of any feed-ing program. Also, for fish fed tosatiation, net returns decreased asthe protein level of the diet was in-creased. Conversely, the 38 per-cent protein diet produced thehighest net return for fish fed on arestricted basis. Finally, althoughponds in which fish were fed to sa-tiation with the 38 percent proteindiet produced 400 more pounds offish per acre than those fed thesame protein level on a restrictedbasis, net returns were essentiallythe same.

Conclusions

Feeding to satiation has some ad-vantages over restricted feeding.Producers can better match theamount fed to the amount neededby growing fish. These studiesalso suggest that fish fed to satia-tion require less protein in theirdiet, which means potentiallylower feed costs. There are alsosome drawbacks to this feedingmethod. Increasing the amount offeed added to ponds increases therisk and frequency of severe waterquality problems. Also, feeding tosatiation requires more time andmore skilled management thandoes restricted feeding. Theeconomic tradeoffs betweenmoney saved by feeding a lowerpercentage protein diet and theneed for increased managementare not fully known.

Cage culture of catfish is often practiced in Kentucky ponds. Sampling of cage-reared catfish.

Production of third-yearfish in ponds

Although third-year fish are notraised commercially in many partsof the country, larger fish are pre-ferred by some consumers as wellas by operators of recreational put-and-take fisheries. However, littleinformation regarding how diet af-fects the growth rate and feedingefficiency of third-year fish is avail-able,

A study at Auburn Universitymeasured the effects of feedingcommercial-type diets containing24, 28, 32, 36 or 40 percent proteinto third-year catfish in ponds. Fishwere stocked at 1,977 per acre andwent from an average size of 1.3pounds to an average of 3.6pounds in 141 days. They were fedto satiation once daily. Fish fed the24 percent protein diet gainedweight fastest. Increased proteinactually reduced feed consump-tion and weight gain. These resultsindicate that third-year fish growbetter on the lower protein dietwhen fed to satiation.

In a Kentucky State Universitystudy, 1,482 third-year catfish

were stocked per acre into re-search ponds. The fish were fedcommercial-type 32 or 38 percentprotein diets to satiation eitheronce or twice daily for 170 days.Neither the protein level of thediet nor feeding frequency af-fected the growth rate, survival,feed conversion ratio, specificgrowth rate or production perpond. These results indicate thatthird-year fish may performequally well on a 32 percent pro-tein diet, which means that spend-ing extra money for higher proteindiets may be unnecessary.

Conclusions

The results of these research stud-ies indicate that producers grow-ing out third-year channel catfishshould consider feeding diets thatcontain 32 percent, or less, crudeprotein, especially if fed to satia-tion.

Catfish production incages

Cage culture offers an opportunityto produce fish in ponds that maybe poorly suited for conventional

pond culture because of their size,depth or the presence of other fish.However, successful cage culturealso provides unique managementchallenges to the producer.

A study at Kentucky State Univer-sity focused on the nutritionalneeds of fingerling channel catfishstocked in cages. Researchersstocked 400 fingerlings in each ofeight, 44-ft3 cages in a 2.5-acrepond. The fish were fed to satia-tion once or twice daily for 105days with complete, commercial-type feeds containing either 34 or38 percent protein. Feeding fre-quency did not affect the growthor food conversion efficiency ofthe fingerlings. Producers whofeed caged fish more than oncedaily may not benefit from theextra effort. However, the proteincontent of the feed was important.Fish fed the 38 percent protein dietgrew faster, and cages receivingthe higher protein feed producedmore pounds of fish. Cage-rearedcatfish may require more proteinthan pond-reared fish becausethey do not have access to naturalfoods in the pond.

References

Li, M. and R. T. Lovell. 1992. Com-parison of Satiate Feeding andRestricted Feeding of ChannelCatfish with Various Concentra-tions of Dietary Protein in Pro-duction Ponds. Aquaculture(submitted for publication).

Li, M. and R. T. Lovell. 1992.Growth, Feed Efficiency andBody Composition of Second-and Third-Year Channel CatfishFed Various Concentrations of

Dietary Protein to Satiety in Pro-duction Ponds. Aquaculture(submitted for publication).

Webster, C. D., J. H. Tidwell, J. A.Clark and D. H. Yancey. 1992.Effects of Feeding Diets Con-taining 34 or 38% Protein atTwo Frequencies on Growthand Body Composition of Chan-nel Catfish. Journal of AppliedAquaculture Vol 1(3)67-79.

Webster, C. D., J. H. Tidwell andD. H. Yancey. 1992. Effect ofProtein Level and Feeding Fre-

quency on Growth and BodyComposition of Cage RearedChannel Catfish. The Progres-sive Fish-Culturist Vol. 54:92-96.

Webster, C. D., J. H. Tidwell, L. S.Goodgame, J. A. Clark and D.H. Yancey. 1992. Effects of Pro-tein Level and Feeding Fre-quency on Growth and BodyComposition of Third-YearChannel Catfish Reared inPonds. Journal of AppliedAquaculture (in press).

The work reported in this publication was supported in part by the Southern Regional Aquaculture Center through Grant No. 89-38500-4516 from the UnitedStates Department of Agriculture.