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Use of Immunostimulants and Nucleotides in Aquaculture: A Review

2011; OMICS Publishing Group; Volume: 02; Issue: 01 Linguagem: Inglês

10.4172/2155-9910.1000104

2155-9910

Einar Ringø, Rolf Erik Olsen, Jose L. González Vecino, Simon Wadsworth,

Invertebrate Immune Response Mechanisms

Currently there are numerous gaps in existing knowledge about exogenous nucleotide application to fish including various aspects of digestion, absorption, metabolism, and influences on various physiological responses, especially expression of immunogenes and modulation of immunoglobulin production. Additional information is also needed in regard to age/size-related responses and appropriate doses and timing of administration. Thus further research in these areas should be pursued. Immunostimulants Abstract It is well established that proper nutrition is essential for maintenance of normal growth and health of all animals including various aquatic species. During the last two decades increased attention has focus on immunostimulants and nucleotides to reduce susceptibility to various stressors and diseases, as well as enhance the overall health of fish. The immune response can be modulated by β-glucans and high-M-alginate. β-glucans are glucose polymers that are major structural components of the cell wall of yeast, fungi, and bacteria, but also of cereals like oat and barley. There is much structural variation in the β-glucans from these different sources, which may influence their physiological functions. Alginate is a polysaccharide composed of β-1,4-D-mannuronic acid (M) and α-L-glucuronic acid (G). In vitro as well as in vivo studies in fish show that especially β-glucans derived from fungi and yeast and alginate have immune modulating properties. Most frequently evaluated are effects on macrophage activation and on lysozyme, respiratory burst and leukocyte activity, which have been suggested to contribute to the increased resistance against infections, after immunostimulant exposure. Although more fish studies are needed, it is tempting to suggest that dietary β-glucans and alginate may be useful tools to prime the host immune system and increase resistance against invading pathogens. As no knowledge is available regarding short versus long-term effects and efficiency, more knowledge is needed on this topic.