Effects of Short- and Long-Term Glucan Feeding of Rainbow Trout (Salmonidae) on the Susceptibility to <I>Ichthyophthirius Multifiliis</I> Infections

Abstract

Lauridsen J.H., Buchmann K. 2010. Effects of short-and long-term glucan feeding of rainbow trout (Salmonidae) on the susceptibility to Ichthyophthirius multifiliis infections. Acta Ichthyol. Piscat. 40 (1): 61-66.Background. Various compounds are being used as immuno-stimulants in various aquaculture feed types but the importance of their prolonged use is at present unknown. It is also true for those intended to modify trout susceptibility to white spot disease caused by Ichthyophthirius multifiliis. The immuno-modulating effects on rainbow trout of short-and long-term feeding using dry feed with inclusion of beta-glucan (0.2%) have therefore been evaluated. Materials and Methods. The immune reactivity was assessed by measuring susceptibility to I. multifiliis infections and plasma lysozyme in the host, factors which are considered innate response parameters. Rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (Actinopterygii: Salmoniformes: Salmonidae), were fed (control feed or glucan-containing feed) for 14 or 35 days before challenge (exposure to infective I. multifiliis theronts) and the resulting infection (number of trophonts in the skin) was recorded on day 11 post-exposure to theronts. Results. All fish obtained infection following parasite exposure but glucan-fed fish showed a lower infection at day 46 compared to fish fed control-feed. The lysozyme activity of fish plasma was evaluated throughout the experimental period and found slightly but significantly increased in association with glucan-feeding at day 14, 17, and 46. Conclusion.No evidence for an exhaustion of these selected innate response parameters due to prolonged glucan-feeding could be detected within the experimental period of 46 days.

Desempenho produtivo e respostas fisiopatológicas de tambaquis alimentados com ração suplementada com β-glucano

“…Os dados são apresentados com média±erro-padrão da média (1) . Alguns estudos conduzidos com β-glucano em espécies de peixes sugerem que a administração de dietas suplementadas com este imunoestimulante promove aumento da resistência contra infecções bacterianas e protozoárias (Kumari & Sahoo, 2006;Lauridsen & Buchmann, 2010). Este aumento na resistência a doenças nos peixes se dá, principalmente, pelo aumento dos mecanismos não específicos de defesa (Whittington et al, 2005), como por exemplo o aumento da atividade da lisozima (Paulsen et al, 2003).…”

An assessment of the use of drug and non-drug interventions in the treatment ofIchthyophthirius multifiliisFouquet, 1876, a protozoan parasite of freshwater fish

“…Low concentrations of humic acid (10%) (100-150 μl l − 1 ) were found to disrupt the development of protomonts; however, when the same concentrations were used in vivo, the results were inconsistent and appeared to be highly dependent on water temperature and the treatment regime used (Lahnsteiner and Weismann, 2007). Ling et al (2010) demonstrated that 4·8 mg l − 1 potassium ferrate (VI) for 2 h was very effective in vitro, in killing theronts.…”

The Immune System Drugs in Fish: Immune Function, Immunoassay, Drugs

“…A number of studies have been reported that potential immunostimulants may be showed at in vivo and/or in vitro effects in fish species in different countries and various periods (Aly & Mohamed, 2010;Anas et al, 2005;Dugenci et al, 2003;Galindo-Villegas et al, 1996;Galindo-Villegas et al, 2006;Gildberg et al, 1996;Ispir & Dorucu, 2005;Kunttu et al, 2009;Lauridsen & Buchmann, 2010;Ortuño et al, 2002;Peddie et al, 2002;Perera & Pathiratne, 2008;Sakai et al, 1995;Seker et al, 2011;Soltani et al, 2010;Yin et al, 2009;Zhao et al, 2010).…”

“…Some immunostimulants may induce both antibacterial and antiparasitic effects, whereas other may help the organism to fight virus and fungus. Generally, immunostimulants used in fish and shrimp in many countries can be divided into two main groups as biological substances and synthetic chemicals depending on their sources (Table 9) (Anas et al, 2005;Brown-Treves, 2000;Dügenci et al, 2003;Galindo-Villegas & Hosokowa, 2004;Gannam & Schrock, 2001;Gildberg et al, 1996;Glina et al, 2009;Jiye et al, 2009;Lauridsen & Buchmann, 2010;Maqsood et al, 2011;Noga, 2010;Paulsen et al, 2003;Perera & Pathiratne, 2008;Petersen et al, 2004;Raa, 2000;Sakai, 1999). But, some immunostimulants may be included in different subgroups by some researchers, such as schizophyllan and scleroglucan.…”