Effects of dietary lipid on the hematology of channel catfish, Ictalurus punctatus

Juvenile channel catfish were fed diets containing either soybean oil, menhaden oil, beef tallow, or a combination of these three lipid sources. After 90 days, total erythrocyte, leucocyte, and thrombocyte counts, hematocrit, mean corpuscular volume, plasma recalcification time, erythrocyte counts, leucocyte counts, and mean corpuscular volume were not significantly different (P < 0.05) among dietary groups. However, fish fed the menhaden oil diet had significantly lower (P < 0.05) hematocrits, higher thrombocyte counts, and higher serum for concentrations. They also had the higher concentration of n - 3 fatty acids in the pronephros tissue and their erythrocytes were the least susceptible to osmotic lysis. Catfish fed the beef allow diet had the lowest level n - 3 fatty acids in pronephros tissue and their erythrocytes were the most susceptible to osmotic lysis. Results suggest that dietary lipids affect several hematological factors of cultured channel catfish.