Location: Warmwater Aquaculture Research UnitTitle: Effects of dietary fiber concentrations supplied by corn bran on feed intake growth and feed efficiency of channel catfish Ictalurus punctatus) Author
Submitted to: North American Journal of Aquaculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/18/2011
Publication Date: 4/1/2012
Publication URL: http://handle.nal.usda.gov/10113/55498
Citation: Li, M.H., Oberle, D.F., Lucas, P.M. 2012. Effects of dietary fiber concentrations supplied by corn bran on feed intake, growth, and feed efficiency of channel catfish Ictalurus punctatus. North American Journal of Aquaculture. 74:148-153. Interpretive Summary: Fish generally cannot digest or utilize dietary fiber because of the lack of certain enzymes and appropriate fiber-utilizing microorganisms in the digestive system. As traditional feedstuffs, such as soybean meal and corn, become more expensive, more alternative plant feed ingredients are being used in commercial channel catfish diets. These alternative feedstuffs contain higher levels of fiber than traditional feedstuffs. Knowing the levels of dietary fiber that channel catfish can tolerate will allow fish nutritionists to better formulate the diets that optimize catfish growth and feed efficiency at a lower cost. A laboratory study was conducted to examine the effects of dietary fiber and digestible energy on the feed intake, growth, and feed efficiency of juvenile channel catfish. Results demonstrate that a total dietary fiber level of 23.4% (5.0% crude fiber) appears to be optimum for maximum weight gain of juvenile channel catfish. The maximum tolerance level for total dietary fiber was estimated to be 32.1% (6.6% crude fiber). The tolerance level of dietary fiber may vary depending on digestible carbohydrates, digestible energy, or digestible energy to protein ratio of feedstuffs included in feed formulae. The maximum fiber tolerance levels may be used as upper limits for fiber when formulating practical diets for catfish containing corn by-products.
Technical Abstract: The present study examined the effects of dietary fiber and digestible energy on the feed intake, growth, and feed efficiency of juvenile channel catfish Ictalurus punctatus. Fish with an initial weight of 9.8 ± 0.1 g/fish (mean ± SD) were stocked in 110-L flow-through aquariums and fed for 9 weeks with practical diets that contained graded levels of fiber supplied by corn bran. As total dietary fiber (TDF) increased, feed consumption and weight gain increased and then decreased, showing a quadratic response. Maximum feed consumption occurred at a TDF level of 27.0% (5.7% crude fiber, 19.1% neutral detergent fiber [NDF]). Channel catfish appear to have some ability to adapt to increased dietary fiber by increasing feed intake to satisfy their energy requirements. Maximum weight gain was achieved at a TDF level of 23.4% (5.0% crude fiber, 15.7% NDF), indicating that the presence of dietary fiber at certain levels is beneficial to the fish. The maximum tolerance level for TDF by channel catfish was estimated to be 32.1% (6.6% crude fiber, 24.9% NDF). Feed efficiency, hepatosomatic index, and body fat decreased linearly with increasing dietary fiber. The maximum fiber tolerance levels may be used as upper limits for fiber when formulating practical diets for catfish containing corn by-products.