Abstract Aquaculture needs to optimize production and nutrition of fish. The effects caused by 1, 2, 4 and 20 days of starvation on humoral immunity and bactericidal activity, against Vibrio anguillarum, in blood and skin mucus of gilthead seabream (Sparus aurata) were determined. In addition, several blood biochemical parameters were also analysed in order to test the general health status of the fish and also in an attempt to correlate the physiological changes due to starvation with the changes observed in the immune parameters. Significant decreases in IgM level and protease activity (P-value < 0.05), as well as significant increases in peroxidase and bactericidal activity were obtained in the mucus of the fish after short periods of starvation (from 1 to 4 days), compared to the fed fish. However, it was impossible to determine similar conditions in fish subjected to 20 days of starvation, since all the parameters studied in this group showed very similar values to those obtained for control fish (fed). This could be due to the necessity for fish to recover their homeostasis in order to survive, even when maintained under starvation conditions. The possible relationships between the nutri- tional state and humoral immunity in fish is discussed. Volume 2 • Issue 1 • 2020 Copyright © All rights are reserved María Ángeles Esteban. Journal of Agriculture and Aquaculture Research Article Nora Albaladejo-Riad, Cristóbal Espinosa-Ruíz and María Ángeles Esteban* Dept. of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional “Campus Mare Nostrum”, University of Murcia, 30100, Murcia, Spain. Received: May 31, 2020; Published: June 10, 2020 *Corresponding Author: María Ángeles Esteban, Dept. of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional “Campus Mare Nostrum”, University of Murcia, 30100, Murcia, Spain. Feed Deprivation effects on Bactericidal an Immunological activity of Blood and skin mucus, and on blood Chemistry of Gilthead Seabream (Sparus aurata) Citation: Nora Albaladejo-Riad, Cristóbal Espinosa-Ruíz and María Ángeles Esteban. (2020). Feed Deprivation effects on Bactericidal an Immunological activity of Blood and skin mucus, and on blood Chemistry of Gilthead Seabream (Sparus aurata). Journal of Agriculture and Aquaculture 2(1). Key words: Feed deprivation; Gilthead seabream (Sparus aurata); Immunity; Skin mucus; serum. Abbreviations: 1D: 1 Day of feed deprivation; 20D: 20 Day of feed deprivation; 2D: 2 Day of feed deprivation; 4D: 4 Day of feed de- privation; ALB: Albumin; BA: Biliar Acids; BSA: Bovine serum albumin; CA: Calcium; DMSO: Dimethylsulfoxide; ELISA: Enzyme-linked immune sorbent assay; GLOB: Globulin; GLU: Glucose; HBSS: Hanks’ Balanced Salt Solution; IgM: Immunoglobulin M; MINECO: Ministry of Economy and Competitiveness; MTT: 3-(4, 5 dimethyl-2-yl)-2, 5-diphenyl tetrazolium bromide; NA+: Sodium; OD: Optical density; PBS-T: Phosphate buffer and Tween; PHOS: Phosphate; SE: Standard Error; SGR: Specific growth rate; SHP: Small heterodimer partner; TCA: Trichloroacetic acid; TMB: 3,3’,5,5’-tetramethylbenzidine hydrochloride; TP: Total Protein; UA: Uric acid; Wspecific: Percentage of specific weight