The effects of increasing dietary levels of amino acid-supplemented soy protein concentrate and constant dietary supplementation of phosphorus on growth, composition and immune responses of juvenile Atlantic salmon (Salmo salar L.)

Abstract

Diets with 50 (SPC50), 65 (SPC65) and 80% (SPC80) substitution of prime fish meal (FM) with soy protein concentrate (SPC) were evaluated against a commercial type control feed with 35% FM replacement with SPC. Increases in dietary SPC were combined with appropriate increases in methionine, lysine and threonine supplementation, whereas added phosphorus was constant among treatments. Diets were administered to quadruplicate groups of 29 g juvenile Atlantic salmon were exposed to constant light, for 97days. On Day 63 salmon were subjected to vaccination. Significant weight reductions in SPC65 and SPC80 compared with SPC35 salmon were observed by Day 97. Linear reductions in body cross-sectional ash, Ca/P ratios, and Ca, P, Mn and Zn were observed at Days 63 (prior vaccination) and 97 (34days post-vaccination), while Mg presented a decrease at Day 63, in salmon fed increasing dietary SPC. Significant reductions in Zn, Ca, P and Ca/P ratios persisted in SPC65 and SPC80 compared with SPC35 salmon at Day 97. Significant haematocrit reductions in SPC50, SPC65 and SPC80 salmon were observed at Days 63, 70 and 97. Enhanced plasma haemolytic activity, increased total IgM, and a rise in thrombocytes were demonstrated in SPC50 and SPC65 salmon on Day 97, while increased lysozyme activity was demonstrated for these groups on Days 63, 70 and 97. Leucocyte and lymphocyte counts revealed enhanced immunostimulation in salmon fed with increasing dietary SPC at Day 97. High SPC inclusion diets did not compromise the immune responses of salmon, while SPC50 diet also supported good growth without compromising elemental concentrations

The effects of increasing dietary levels of soy protein concentrate (SPC) on the immune responses and disease resistance (furunculosis) of vaccinated and non-vaccinated Atlantic salmon ( Salmo salar L.) parr

“…No effects of the SPC inclusion levels on specific antibody production were detected, which is in line with the data from the study by Metochis et al [22], on increasing dietary SPC levels on larger size Atlantic salmon parr. Kiron et al [59][60] reported no changes in the specific antibody levels of rainbow trout fed on different dietary protein levels, suggesting that specific antibody production does not seem to depend on dietary protein quantity.…”

“…Furunculosis is a highly infectious disease, causing serious fish losses, such as those observed during the epidemic of 1991-1992, which led to the loss of approximately 25% of the total Scottish salmon production [22]. Successful vaccination has enabled the disease to be brought under control and currently the majority of farmed Scottish and Norwegian Atlantic salmon are vaccinated against fununculosis.…”

“…Generally, soy products and several other vegetable derived products used as FM replacements have been shown to affect a range of immune responses in fishes and these have been interpreted as inflammatory/hypersensitivity or immunostimulatory effects [16,[19][20][21][22].…”

Dietary effects of soybean products on gut microbiota and immunity of aquatic animals: A review

“…While much effort has focused on evaluating the extent of SBM‐induced histological damage, SBM‐induced enteritis (SBMIE) (e.g., Bakke‐McKellep, Press, Baeverfjord, Krogdahl, & Landsverk, ; Bakke‐McKellep, Froystad et al., ; Bakke‐McKellep, Penn et al., ; Bakke‐McKellep, Koppang et al., ; Hedrera et al., ; Krogdahl, Bakke‐Mckellep, Roed, & Baeverfjord, ; Metochis et al., ; Rumsey, Siwicki, Anderson, & Bowser, ), the effects on the intestinal microbiota of fish were not reported until 2006. However, as the importance of the gut microbiota and our awareness of this complex microbial ecosystem have increased the interest in the factors that might modulate the intestinal microbial communities (Ringø et al., ).…”

“…() showed that saponins caused dose‐dependent increases in the severity of inflammation independent of the basal diet, with concomitant alterations in digestive functions and immunological marker expression. In the inflammatory states of SBMIE or SPCIE, plasma immunoglobulin level (Bakke‐McKellep et al., ; Metochis et al., ) and T‐cell numbers (Bakke‐McKellep, Froystad et al., ) were significantly increased. Although the physiology of the immune modulation is not completely understood at present, this activated immune responses may be related to an allergic reaction caused by SBM or SPC.…”