EFFECTS OF DIETARY NUCLEOTIDES ON GROWTH, IMMUNOLOGY, AND DISEASE RESISTANCE OF JUVENILE NILE TILAPIA (Oreochromis niloticus)

Effects of Dietary Nucleotides on Growth, Immunology, and Disease Resistance of Juvenile Nile Tilapia (Oreochromis niloticus). (December 2011) Maritza Anguiano, B.S., Texas A&M University Co-Chairs of Advisory Committee: Dr. Delbert Gatlin Dr. Alejandro Buentello In order to improve production efficiency and profitability in tilapia aquaculture, further research is needed to develop methods to improve weight gain, feed utilization, and immune function of these fish. In this regard, numerous studies with several fish species have reported that dietary nucleotides can enhance growth performance, immune responses and disease resistance. Therefore, two feeding experiments were conducted to investigate the effects of a purified nucleotide mix on juvenile Nile tilapia, Oreochromis niloticus. A basal diet was formulated to contain 34% crude protein from fishmeal and soybean meal. A nucleotide mix containing salts of cytidine, uridine, adenosine, inosine, guanosine, and thymine was supplemented to the basal diet at 0.5, 1 and 2% of dry weight. In the first experiment, three replicate groups of 15 fish were fed the experimental diets. At the end of 8 weeks, weight gain, feed efficiency and survival were computed. Blood samples were analyzed for neutrophil oxidative radical production and plasma lysozyme activity. In the second trial, three replicate groups of 20 fish were fed the same experimental diets. At the end of 4 weeks, blood and kidney samples were