Effects of Saccharomyces cerevisiae supplementation on immune response, hematological parameters, body composition and disease resistance in rainbow trout, Oncorhynchus mykiss (Walbaum, 1792)

Abstract

Summary Natural substances are now generally preferred over chemical and synthetic compounds for the growth and immune enhancement of aquatic organisms. The aim of this study was to evaluate the effect of Saccharomyces cerevisiae extract and hydrolyzed powder on immunity, hematological parameters and body composition in rainbow trout, Oncorhynchus mykiss. Six hundred rainbow trout (50 ± 5 g mean weight) were acclimated to laboratory conditions and then randomly divided into four groups of triplicate tanks. The first group was fed with a commercial diet (control) without supplementation. The second and third groups were given a diet supplemented with 1% of yeast extract and hydrolyzed powder, respectively. The fourth group was also fed with a basal diet supplemented with 0.5% of both substances. Fish were cultured in 300‐L polyethylene tanks for 60 days; immune and hematological parameters, fillet composition and disease resistance were analyzed at days 0, 30 and 60. Results showed that a combination of Saccharomyces cerevisiae extract and hydrolyzed powder could improve the immunity and alter hematological parameters of the rainbow trout compared to the control. Mortality rates of fish fed yeast extract and hydrolyzed powder were also lower than in fish fed the control diet after challenging with Yersinia ruckeri. There were no significant changes in rainbow trout fillet composition compared to the control. It can be concluded that fish diet supplementation with a mixture of yeast extract hydrolyzed powder is preferable compared to each one used alone.

Yeast derived from lignocellulosic biomass as a sustainable feed resource for use in aquaculture

“…There are few data on effects of processing on digestibility, and whether different yeasts require different processing methods. It has been suggested that the thick and rigid cell walls are a major problem inhibiting industrial production and utilisation of dietary yeast protein . A poorly digestible cell wall may limit enzymatic access to cellular contents, depending on yeast cell characteristics as well as growth substrate and processing conditions.…”

“…Various chemical, enzymatic, physical or mechanical methods can be used to rupture the yeast cell walls (reviewed by Nasseri et al ). Digestibility of yeast nutrients can be increased by mechanical rupturing of cell walls or enzymatic hydrolysis . Enzymatic pre‐treatment followed by high‐pressure mechanical homogenisation have been shown to be efficient for C. utilis .…”

“…Positive health effects have been documented when adding yeast to fish diets at low levels (10–40 g kg −1 ), especially with whole S. cerevisiae yeast or yeast products, but few studies evaluate the health beneficial effects of yeast when used as a protein source. Low levels of S. cerevisiae yeast have shown to enhance growth performance, immune responses, and/or protection against bacterial infection, and to increase disease resistance in several fish species, such as salmonids, hybrid striped bass, gilthead seabream, seabream, hybrid tilapia ( Oreochromis niloticus ), common carp, Indian common carp ( Labeo rohita ), channel catfish ( Ictalurus punctatus ), Japanese seabass ( Lateolabrax japonicas ), and Nile tilapia . Yeasts such as C. utilis have also been shown to modulate immune responses in rainbow trout, and K. marxianus has shown probiotic properties in an in vitro colonic model system .…”

Artemia enriched with hydrolyzed yeast improves growth and stress resistance of marine pejerrey Odontesthes argentinensis larvae

“…These results are in agreement with those of Li et al (2005) concluded that dietary supplemented diet of Juvenile red drum (Sciaenops ocellatus) with Brewer's yeast (S. cerevisiae) did not promote resistance to handling stress. Many studies however, show greater resistance to salt stress (Pooramini et al, 2014) or pathogens challenge (Chiu et al, 2010;Tukmechi and Bandboni, 2014;).…”

“…However, one problem of using yeast in the diet is the low digestibility of the yeast cell walls. Digestibility of the yeast can be increased through enzymatic hydrolysis, during which a high volume of nucleic acids is released (Tukmechi and Bandboni, 2014).…”