In the present study we investigate the dietary administration effects of uridine monophosphate (UMP) to enhance the growth, hematological profile, innate and adaptive immune functions and stress resistance of juvenile red sea bream, Pagrus major. A casein fishmeal based semi-purified basal diet supplemented with 0% (control), 0.1% (UMP-0.1), 0.2% (UMP-0.2), 0.4% (UMP-0.4) and 0.8% (UMP-0.8) purified UMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (mean initial weight 2.9g) for 56days. In general dietary UMP supplementation tended to improve growth performances (final body weight, % weight gain and specific growth rate), in which significantly higher performances were found in diet group UMP-0.4 followed by diet groups UMP-0.8, UMP-0.1 and UMP-0.2. UMP supplementation resulted increased feed conversion efficiency and protein efficiency ratio and significantly higher value (P<0.05) obtained in diet groups UMP-0.4 and UMP-0.8. Feed intake also increased numerically (P>0.05) with dietary UMP supplementation. Fish in control group without UMP supplementation showed significantly lower growth and feed utilization performances. The capabilities of enhancing immune responses of fish fed UMP supplemented diets were detected by nonspecific and acquired immune parameters measured in this study. Peroxidase activity (PA) was significantly higher in fish fed diet group UMP-0.8 and higher (P<0.05) total serum protein (TSP) values obtained in diet groups UMP-0.4 and UMP-0.8. Fish fed diets with UMP supplementation had an increase adaptive humoral immune response (antibody titer) after 15 and 21days of vaccination of formalin killed Vibrio anguillarum. In the 15th day after vaccination, significantly higher agglutination antibody titer was found in diet group UMP-0.4 and simultaneously other supplemented diet groups showed intermediate values. In terms of oxidative stress, diet group UMP-0.4 showed best condition with low oxidative stress and high antioxidant levels. Moreover, the fish fed UMP supplemented diets had better improvement (P<0.05) in body lipid contents, hepatosomatic index, glucose and hematocrit content than the control group. Considering the calculated UMP content of the basal and other experimental diets, the quadratic regression analysis of weight gain and agglutination antibody titer revealed that the optimal levels of dietary UMP were 0.48 and 0.59%, respectively, for juvenile red sea bream, which is also in line with the most of the growth and health performance parameters of the fish.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.