Dietary ARA, DHA, and Carbohydrate Ratios Affect the Immune Status of Gilthead Sea Bream Juveniles upon Bacterial Challenge

This study aims to assess the effects of different dietary n-6/n-3 long-chain polyunsaturated fatty acid ratios and CHO content in immune response gilthead seabream. For that purpose, sea bream juveniles (initial body weight = 47.5 g) were fed for 84 days with four isoproteic (47% crude protein) isolipidic (18% lipids) diets high (20%) or low (5%) level gelatinized starch (HS LS diets, respectively) included approximately 2.4% ARA DHA. At end trial, DHA-enriched groups presented increased red blood cell (RBC) count, hemoglobin, plasmatic nitric oxide (NO) content, antiprotease alternative complement activities. The had thrombocyte bactericidal activity against Vibrio anguillarum was lower fish ARA/LS diet. After feeding challenged an intraperitoneal injection (i.p.) killed Photobacterium damselae subsp. piscicida (Phdp) sampled at 4 24 h after challenge. i.p., plasma total immunoglobulins (Ig) V. anguillarum. In addition, diet white (WBC) activity. RBC, WBC, numbers, IG, peroxidase activity, casp3 expression distal intestine. HS NO Phdp decreased protease, conclusion, DHA levels seemed improve status unchallenged juveniles, while improved a bacterial energy provided by seems be important promote fast system