Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2007
Publication Date: February 9, 2008
Citation: Kobayashi, Y., Peterson, B.C., Waldbieser, G.C. 2008. Cocaine- and Amphetamine-Regulated Transcript (CART) Messenger RNA Expression is Regulated by Food Intake in the Brain of the Channel Catfish (Ictalurus punctatus). Aquaculture America Conference. P: 184 Technical Abstract: Increased growth is included as a selection criterion at the USDA Catfish Genetics Research Unit, Stoneville, MS, USA. Faster growth of selected channel catfish is typically attributed to their ability to consume more feed. While endocrine and neural factors and mechanisms that regulate feed intake in catfish are largely unknown, cocaine- and amphetamine-regulated transcript (CART) has been shown in mammals and some fish species to be involved in suppression of feed intake. Our current research examined whether CART was involved in the regulation of feed intake in the channel catfish that were fed (fed daily for 45 days) or restricted (not fed for 30 days followed by feeding for 15 days). The channel catfish CART gene was cloned from genomic DNA using primers designed based on sequence homology between the zebrafish and pufferfish CART genes. The catfish CART gene was highly similar to zebrafish CART (88%) and goldfish CART type I (90%), and also similar (>70%) to mammalian CART genes. Furthermore, the predicted catfish CART peptide sequence was highly similar to that of the goldfish CART I (72%) and CART II peptides (77%). Expression of CART mRNA was detected in the brain and the testis of the channel catfish but not in liver, heart, spleen, or kidney. The amount of CART mRNA in the brain was 2.5 fold less in the restricted catfish on day 30 compared to those who were fed daily (P =0.06). After 15 days of refeeding, levels of CART mRNA in the brain were restored in restricted catfish to those of catfish that had been continuously fed. Our results suggest the biochemical properties and physiological functions of CART in the channel catfish are similar to that of mammals and other fish species. Further investigations will establish the mechanisms that regulate expression of CART in the catfish brain and whether changes in expression of CART in the brain are associated with selection toward faster growth.