Influence of feeding the leucine metaboliteβ-hydroxy-β-methylbutyrate (HMB) on the non-specific cellular and humoral defence mechanisms of rainbow trout (Oncorhynchus mykiss)

Abstract

Summary Previous studies have shown that leucine metabolite β‐hydroxy‐β‐methylbutyrate (HMB) increases the immune function in animals as measured by cellular and humoral immune responses. In the present study the influence of feeding HMB on the nonspecific cellular and humoral defence mechanisms and protection against furunculosis in rainbow trout (Oncorhynchus mykiss) was examined. HMB was fed in a pelleted ration at either 0 (control), 10, 25 or 50 mg kg−1 bw day−1 for 8 weeks. Blood and pronephros cells were taken at random from 10 fish in each group for the analyses. The respiratory burst activity (RBA) and potential killing activity (PKA) of phagocytes, lymphocyte proliferation stimulated by either concanavalin (ConA) or lipopolysaccharide (LPS), lysozyme activities and total immunoglobulin (Ig) levels in plasma were analysed at 0, 1, 2, 3, 4, 6 and 8 weeks. After 4 weeks of feeding HMB, a challenge test was performed by injection of Aeromonas salmonicida into the fish. HMB approximately doubled the respiratory burst activity and potential killing activity ability of polymorphonuclear (PMN) and morphonuclear (MN) cells (P < 0.01) and increased the mitogen‐stimulated lymphocyte proliferation (P < 0.01) when compared with the control group. HMB feeding also increased (P < 0.01) the lysozyme activity in plasma and total Ig levels in serum. During the 14‐day challenge test, mortality was decreased (P < 0.01) by up to 62% in HMB‐fed fish compared with the control group mortality. In conclusion, the non‐specific immune enhancement by HMB resulted in protection against furunculosis in the rainbow trout.

Improving disease prevention and treatment in controlled fish culture

“…Increases in the parameters of the innate cellular and humoral responses studied were statistically significant at all doses and for all periods that were observed. Additionally, after experimental infection, HMB in all of the doses treated reduced mortality between 20 and 50% depending on the species and the length for which the supplement was administered (Siwicki et al 2000c(Siwicki et al , 2003c. Similar effects were obtained in in vivo studies of pikeperch (Siwicki et al 2005a(Siwicki et al , 2005b(Siwicki et al , 2006a.…”

“…Using vaccines and natural or synthetic preparations that have a stimulatory effect on both innate cellular and humoral defense mechanisms has limited losses caused by disease in fisheries practice. The positive effects of immunoprophylaxis are especially seen in salmonid culture and in species that are new to culture (silurids, sturgeon, pikeperch, pike, eel, tench) (Siwicki et al 1996b, 2003c, 2004c, 2005a, 2006a, 2010e, 2011d, 2015, Kolman et al 2000, Jarmo³owicz et al 2012, Kazuñ and Siwicki 2013, Kowalska et al 2015. Currently, immunoprophylaxis is divided as follows:…”

The influence of $$\upbeta$$ -hydroxy- $$\upbeta$$ -methylbutyrate (HMB) on cell-mediated immunity in tench Tinca tinca (L.): in vitro and in vivo study

“…3-Hydroxy-3-methylbutyrate has been shown to be an immunomodulating compound of proliferative response of T and B lymphocytes in European catfish (Silurus glanis) at different temperatures and suggested that HMB could be used to provide the nonspecific cell-mediated immune responses suppressed by temperature in European catfish intensive culture (Siwicki et al 2004). Several previous in vitro and in vivo studies with HMB in rainbow trout and carp strongly suggest that HMB affects the macrophage and lymphocyte function, enhancing the fish resist function and ability to fight disease effectively (Siwicki et al , 2003.…”

“…Several feeding studies with HMB have shown that HMB may be able to help animals survive environmental stresses and disease challenges (Nissen et al 1994;Ostaszewski et al 1998;Peterson et al 1999;Siwicki et al 2004). In our preliminary in vitro study, we presented that HMB at different concentrations activated the lymphocyte proliferation in rainbow trout (Siwicki et al 2003).…”

Differences in Nutritional Value and Amino Acid Composition of <i>Moina macrocopa</i> (Straus) Using Yeast <i>Saccharomyces cerevisiae</i> and <i>Rhodotorula glutinis</i> as Fodder Substrates

“…Feeding of zooplankton with carotene-synthesizing yeast was accompanied by an increase in the level of isoleucine and leucine also. As was previously shown, the derivatives of these amino acids, in particular β-hydroxyl-β-methyl-butyrate as a leucine metabolite, had the stimulating effects on the growth and immune system state of some fish species [32,33]. For example, branched-chain amino acids, namely valine, leucine and isoleucine, are important in the work of immune cells because of their important role in the synthesis of proteins, including various antibodies, immunoglobulins and acute phase proteins [34].…”