Dietary administration of nucleotides to enhance growth, humoral immune responses, and disease resistance of the rainbow trout (Oncorhynchus mykiss) fingerlings.
A feeding study was conducted to determine the effect of dietary nucleotides (NT) on growth performance, immune responses and resistance of rainbow trout fingerlings to Streptococcus iniae. A basal diet supplemented with 0 (control), 0.5, 1, 1.5 and 2 g NT kg(-1) to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish with initial average weight of approximately 23 g. After 8 weeks of feeding trial, fish fed diets with 1.5-2 g NT kg(-1) had the highest final weight and SGR, followed by groups fed the diets with 0.5-1 g NT kg(-1), and lowest in fish fed the NT-free control diet. The feed conversion ratio (FCR) was better when the fish were fed diet with 2 g NT kg(-1). The ACH(50) level and lysozyme activity in serum were found to be significantly (P < 0.05) greater in fish fed nucleotides at 1.5-2 g kg(-1). The fish fed with 2 g NT kg(-1) had higher IgM level. The challenge experiment showed that relative percent survival (RPS) increased significantly (P < 0.05) with increasing levels of nucleotides from 0.5 to 2 g kg(-1) and was lowest in the control group. We therefore recommend dietary nucleotide administration at 1.5-2 g kg(-1) to promote growth and enhance immunity and resistance against S. iniae.
Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr Marine Science and Technology University, Khorramshahr, Khouzestan, Iran.
Ahmad
A
Tahmasebi-Kohyani
Saeed
S
Keyvanshokooh
Amin
A
Nematollahi
Nemat
N
Mahmoudi
Hossein
H
Pasha-Zanoosi
D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005393:Fish Diseases / Q000276:immunology* / Q000517:prevention & control; D009113:Muramidase / Q000378:metabolism; D009711:Nucleotides / Q000494:pharmacology*; D017686:Oncorhynchus mykiss; D013290:Streptococcal Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary
D009711:Nucleotides; D009113:Muramidase