LAUSR

Abstract There is no definitive evidence associated with administration duration of nucleotide on aquaculture organisms. This study evaluates the long-term feeding effects of cytidine monophosphate (CMP) nucleotide as functional supplement on growth, health conditions of red sea bream, Pagrus major. A formulated basal diet added with 0% (control), 0.2% (CMP-0.2) and 0.4% (CMP-0.4) individual CMP nucleotide to prepare three experimental feeds. Each experimental feed was fed to triplicate tanks of red sea bream (3.0 ± 0.01 g) for 150 days. At day 50th, growth performances were influenced significantly by dietary CMP inclusion and fish fed CMP-0.4 diet showed significantly higher value. In day 100 and 150 growth performances also non-significantly enhanced by CMP supplementation. Feed utilization performances also showed improved values in nucleotide included diets compared to the non-supplemented control diet (P > 0.05). No significant changes observed on measured hematological parameters by nucleotide administration duration. Lysozyme activity (LA) and total serum protein (TSP) significantly rose to their highest level on 50 days in CMP-0.4 diet group. In 100 and 150th day supplementation also improved TSP and LA values and it reaches maximum in CMP-0.2 diet group (P > 0.05). Oxidative radical production (nitro-blue-tetrazolium assay) and the activity of peroxidase and catalase were not affected significantly with feeding nucleotide in all sampling days. Supplementation of nucleotide improved oxidative stress tolerance capacity. Remarkably, CMP-0.2 diet group showed the least oxidative stress condition in 50th and 100th day. In 150th day fish showed acceptable but reduced oxidative stress resistances. On the basis of the overall findings, finally we concluded that, CMP nucleotide administration regime influences the optimum growth, health performance and immune response of Pagrus major and its mostly after feeding for 50 days, but not after 100 days.