Investigation of the effect of dietary supplemented with autolyzed yeast Saccharomyces cerevisiae on biochemical indicator changes (cholesterol and glucose) and the relative expression of some genes involved in immunity (LYZ and TNF-α) in zebra fish (Dani

Abstract

Introduction: Yeasts are one of the most important and widely microorganisms used in food
industry. Therefore, the present study was conducted to investigate the effect of dietary enriched
with autolyzed Saccharomyces cerevisiae yeast on body biochemical parameter changes
(cholesterol and glucose) and the relative expression of some genes involved in immunity (LYZ
and TNF-α) in zebrafish.
Materials & Methods: For this aim, a number of 480 pieces of healthy zebra fish with an
average weight of 0.18 ± 0.08 grams were completely randomly placed in aquariums with a
water volume of 40 liters under different treatments of autolyzed yeast including 1 (AY1), 2
(AY2) and 5 (AY3) percent of diet along with a control group (0- basal diet) (three replicates)
and were fed at 5% of body weight for 60 days. At the end of the trial, in order to check the
biochemical index of the body (glucose and cholesterol) from all the treatments were completely
randomly sampled to prepare the body extract (5 pieces from each replicate). Also, the
expression of genes involved in immunity, including: LYZ and TNF-α, was evaluated using the
whole-body method (3 parts of each replicate).
Results: The results obtained from gene expression after calculation by 2-ΔΔct formula and also
other data were analyzed using SPSS software (version 21) through one-way analysis of
variance. The results showed that the lowest amount of glucose was significantly observed in the
control group (51.86±1.48 g dL-1) (P<0.05). The group fed with 2 (37.07±1.48 g mL-1) and 5
(43.37±1.02 g mL-1) percent of autolyzed yeast had higher cholesterol level compared to the
control group (25.68± 2.43 g mL-1) and AY1 treatment (27.04 ± 4.57 g mL-1) (P<0.05). The
highest relative expression of genes involved in immunity was significantly observed in AY3
treatment (feeding with autolyzed yeast at 5% of diet) (P<0.05).
Conclusion: In general, the results of this research showed that autolyzed yeast could improve
some biochemical indicators of the body and the expression genes involved in the immunity in
zebrafish. The best suggested level in the current research is 5% of autolyzed yeast in diet, which
can be introduced as an immune stimulant to zebra fish breeding farmed.