ARS | Publication request: FEEDING FREQUENCY, GROWTH, GRHRELIN, AND NPY MRNA IN NORRIS AND NWAC103 CHANNEL CATFISH (ICTALURUS PUNCTATUS)

Submitted to: Fish Biology Congress
Publication Type: Abstract Only
Publication Acceptance Date: March 23, 2006
Publication Date: July 18, 2006
Citation: Peterson, B.C., Small, B.C. 2006. Feeding frequency, growth, grhrelin, and npy mrna in norris and nwac103 channel catfish (ictalurus punctatus). Abstract, VIIth International Congress on the Biology of Fish in St. John's Canada, July 18-23, 2006, p. 183.

Technical Abstract: Fish growth is influenced by feed availability and intake, genetics, environment, and nutrition. Of these factors, feed intake is perhaps the principal factor affecting growth rate of catfish. We examined the effect of feeding frequency on growth performance and abundance of ghrelin and NPY mRNA of juvenile Norris and NWAC103 strains of channel catfish reared under laboratory conditions. Catfish (4.0 ± 0.2 g/fish) were fed to visual satiety at different feeding frequencies (one, two, or three times daily). Specific growth rate and feed intake were higher in fish fed three times daily compared to once and twice daily for both strains. Feed efficiency was reduced in NWAC103 fed three times daily compared to fish fed once or twice while feed efficiency was similar among the Norris treatments. Gastrointestinal (GI) tract index [(weight of GI tract/weight of fish) x 100] decreased in NWAC103 catfish as feeding frequency increased while a similar nonsignificant trend was also observed in Norris catfish. Feeding frequency did not increase abundance of stomach ghrelin or brain NPY mRNA in either strain. Results demonstrate that aquarium reared Norris and NWAC103 catfish fed three times a day consume more feed and gain more weight than catfish fed once or twice a day. The observed decrease in the GI index due to feeding more frequently demonstrates that the size of the GI tract increases, relative to body weight, when catfish are fed only once a day. Feeding catfish under laboratory conditions once a day is similar to twice a day for growth and feed efficiency; however, feeding three times daily increased growth rates for both strains of catfish. Feeding frequency does not appear to affect ghrelin or NPY mRNA expression. Funded by USDA-ARS.