ABSTRACT
Zinc [Zn] is an essential trace element in all living organisms, and the first eukaryotic Zn uptake transporter was discovered in the yeast, Saccharomyces cerevisiae. Zinc-enriched yeast is a currently available Zn supplement. The purpose of the investigation was to compare and evaluate the effect of Zn enriched yeast in rainbow trout. The fish [mean body weight 10 +/- 0.5 g] were fed a commercial diet supplemented with 0 [control], 1 × 106, 1 × 107 and 1 × 108 CFU/g of Zn-enriched yeast for 60-days. Results showed that significant increase in serum lysozyme activity, complement activity and total immunoglobulin were seen in all treatment groups during feeding trial when compared to the control group. On the basis of our findings, Zn-enriched improved rainbow trout growth, some immune parameters and disease resistance.
ABSTRACT
Propolis, a resinous substance collected by Apis mellifera bees from various plant sources is transformed in the presence of bee enzymes. Short- and long-term effects of diet supplementation with ethanol extract of Iranian propolis [EEIP] was investigated on growth and immunity in juvenile rainbow trout. The fish [mean body weight 30 +/- 3.2 g] were fed a commercial diet supplemented with 0 [control], 1, 2 and 5 g/kg EEIP for 96 h and 0, 0.5, 1 and 2 g/kg EEIP for a 45-days. Rainbow trout growth performance significantly [P<0.05] increased by the dietary supplementation of Iranian propolis. Our results showed that significant increase in serum lysozyme activity, complement activity and total immunoglobulin were seen in all treatment groups during short- and longterm feeding trial when compared to the control group. On the basis of our findings, propolis improved rainbow trout growth performance and some immune parameters. Key words: Rainbow trout, Iranian propolis, Growth performance, Immunity
ABSTRACT
Mycoestrogen zearalenone [ZEA] is found in human foods and animal feeds. Its estrogenic potency mainly depends on its biotransformation fate. The hepatic biotransformation of ZEA in rainbow trout was investigated in this study. Various concentrations of ZEA were separately incubated with the hepatic microsomal and post-mitochondrial sub-fractions in the presence of NADPH, and the metabolites were determined by means of HPLC. Moreover, the rate of glucuronidation for ZEA and its reduced metabolites were estimated in the presence of uridine diphosphate glucuronic acid. beta-zearalenol [beta-ZOL] was found to be the major metabolite of ZEA by both sub-cellular fractions. The enzymatic kinetics analyses indicated that the alpha-ZOL and beta-ZOL production by microsomal fraction were 8- and 2-fold higher than those by post-mitochondrial fraction, respectively. High percentages of ZEA and its metabolites are conjugated with glucuronic acid at the lower concentrations. Data suggest that the hepatic biotransformation of ZEA in rainbow trout resulted in its detoxification as the main metabolite tends to be beta-ZOL with weak estrogenic property. Moreover, at certain concentrations, the produced metabolites are entirely conjugated with glucuronic acid, which may consequently cause a prolonged duration of action due to entero-hepatic cycle