Nutrition and immunity: an update

Abstract

Immunity encompasses all mechanisms and responses used by the organism to defend itself against bacteria, viruses or parasites. Adequate supply and balance of nutrients are required for proper e⁄ciency of the host defences. Research has identi¢ed dietary factors that a¡ect human and animal immune responses like amino acids, fatty acids, minerals and vitamins. Some of these nutrients have been proven to have speci¢c actions on immunity when provided at pharmacological doses. This paper will review these nutrients and their current use in aquaculture. The immune system is an e⁄cient but complex system. Its complexity has made the assessment of the e¡ects of diets di⁄cult. Nevertheless, the standardization of methodology as well as the use of new techniques at the cell or the gene level should help to better understand the mechanisms of immune modulation. This paper will review the major functions of ¢sh and shrimp immune system and the methodologies used. Cellular and humoral functions including cytokines will be discussed in relation to potential means to modulate them and the underlying mechanism. A better understanding of the mechanisms of modulation of the immune functions should help in the discovery of new dietary factors to improve the immune status of the animal, leading to better disease resistance.

Effect of dietary arginine on the immune response and gene expression in head kidney and spleen following infection of Jian carp with Aeromonas hydrophila

“…In teleosts, the head kidney and spleen are two important hematopoietic organs [10]. In the present study, head kidney and spleen weights of Jian carp increased with increasing dietary arginine concentrations, suggesting beneficial effects of arginine on head kidney and spleen growth.…”

The impaired intestinal mucosal immune system by valine deficiency for young grass carp (Ctenopharyngodon idella) is associated with decreasing immune status and regulating tight junction proteins transcript abundance in the intestine

“…Study have shown that the immune response of fish is highly association with the lymphocytes which involved in the production of antibacterial compounds [54]. In vitro, omission of valine almost completely inhibited the proliferation of lymphocytes [55].…”

Dietary riboflavin deficiency decreases immunity and antioxidant capacity, and changes tight junction proteins and related signaling molecules mRNA expression in the gills of young grass carp (Ctenopharyngodon idella)

“…It was reported that gills of fish owned mucosa associated lymphoid tissues, which harbored macrophages, neutrophils, lymphocytes and mast cells/eosinophilic granulocytes [4]. Studies have reported that these immune cells, like monocytes, macrophages and lymphocytes could synthesise and secrete antibacterial compounds [11,59]. Grimble [12] indicated that riboflavin deficiency could reduce cell numbers in lymphoid tissues of experimental animals and produce functional abnormalities in the cell mediated immune response, meanwhile, decreased reduced GSH content could reduce lymphocyte replication.…”

“…It was reported that fish gill owned mucosa associated lymphoid tissues, which harbor lymphocytes [4]. Trichet [11] reported that lymphocytes could produce antibacterial compounds in fish. Moreover, it has been reported that reduced glutathione play important role in lymphocyte replication in human [12].…”