Aquaculture Nutrition, Early View (Online Version of Record
published before inclusion in an issue)
To study the effect of propolis in crude form (CPP),
prepared without any chemical refinement (CPP) on Dicentrarchus labrax under
low-temperature stress, sea bass juveniles were randomly divided into three
groups: a control group fed with basal diet and two treatment groups fed with
basal diet supplemented with 1.25 and 2.5 g kg−1 of propolis.
At the end of a 10-week feeding trial, sea bass were exposed
to low-temperature stress at 12 °C for 24 h. The growth performance, RNA/DNA
ratio and changes in serum biochemical parameters were investigated. Dietary
intake of propolis stimulated the specific growth rate (SGR), feed conversion
efficiency (FCE), RNA/DNA ratio and alkaline phosphatase (ALP) enzyme activity,
while decreasing plasma triglycerides and aspartate aminotransferase (AST)
activity. Supplement of 2.5 g kg−1 CPP in diet significantly increased the mean
SGR and FCE up to 9% and 13.4%, respectively, in comparison with the control
group. Low-temperature stress elevated serum triglycerides, glucose and cortisol
levels in all groups; however, glucose and cortisol reached significantly lower
end values in group receiving highest amount of propolis in diet.
This study suggests that ingestion of basal diet
supplemented with 2.5 g kg−1 of propolis could prevent adverse effects of
low-temperature stress and promote the growth of sea bass.
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