Detection of Mycotoxins in Poultry Eggs

MATERIALS AND METHODS

Research was conducted in coordination with the laboratories of the College of Veterinary Medicine/University of Baghdad and the Iraqi Ministry of Science and Technology.

Collection of samples: A total of 100 egg samples were randomly collected from various laying poultry farms in Diyala province from November 2016 to March 2017. Samples were kept on ice during their transportation to the laboratory where they were kept at 4°C until analysis.

Chemicals: All reagents and solvents were HPLC or analytical grade. Standards of FU and ZON were purchased from Sigma. The analysis was performed on an Agilent 1200 Series HPLC with a diode array detector (DAD). The analytical column was an Agilent ZORBAX Eclipse Plus C18 2.1 mm×100 mm, 1.8 μm. An Agilent 0.22 μm nylon syringe filter was used to filter the sample solution before HPLC.

Extraction and cleanup of sample: Ten grams of egg samples without eggshell was homogenized with a blender for 5 min at room temperature and placed into a 100 mL centrifuge tube with 40 mL 84:16 (v/v) acetonitrile:water. Samples were then homogenized for 3 min with a high speed homogenizer and centrifuged at 10,000 r/min for ten mins at 4°C. The supernatant was completely evaporated under a stream of nitrogen at 50°C. The residue was redissolved in 8 mL 50:50 (v/v) ethyl acetate/cyclohexane and passed through a 0.45 μm nylon filter. Then, 20 μL was subjected to HPLC analysis¹¹.

Statistical analysis: All data were analyzed using a one-way ANOVA test. Differences were considered significant at p≤0.05. SPSS (version 22) was used for statistical assessments.

RESULTS

The results obtained from the analysis of mycotoxins (FU and ZON) in the laying poultry egg samples are presented in Table 1. The predominant mycotoxin for all analyzed samples was FU. The incidence of FU and ZON in all the samples was 94 and 82%, respectively. No significant differences were found between the median FU and ZON contents for samples (p<0.05).

Table 1:	HPLC data for the occurrence of mycotoxins in poultry egg samples

DISCUSSION

The progress of poultry production is a result of diverse technological developments in nutrition and management techniques. However, significant economic losses may occur due to the presence of natural feed contaminants such as mycotoxins, which are secondary metabolites produced by fungi that naturally grow in cereals and other grains. Mycotoxins influence the metabolism of poultry by reducing the activity of the enzymes that digest starch, proteins, lipids and nucleic acids, decreasing blood protein, total cholesterol and urea and increasing the activity of serum enzymes that indicate liver damage¹². The main manifestations of mycotoxin infection in layers are reduced egg production, reduced weight and increased liver fat levels¹³.

Of the main egg components (yolk, albumen and shell), the yolk has the longest development time. Precursors to yolk lipoproteins are produced in the liver and transported through circulation to the yolk follicles in the ovary. In an active laying hen, several follicles at varying developmental stages reside simultaneously in the ovary. Before an egg is laid, the yolk undergoes a stage of rapid growth, during which it increases in size exponentially over 10 days¹⁴. Mycotoxins that deposit in the yolk will rapidly accumulate during this time and can be presented in successive eggs for 10 or more days following treatment. Following yolk maturation, the albumen, or "egg white," is laid down over a period of 2-3 h and can also serve as a residue accumulation site. Residues are found in egg albumen at low levels and in egg yolks at similar concentrations to those found in kidney and liver for several days following oral dosing¹⁴.

CONCLUSION

These findings indicate that there may be a risk for animal exposure to mycotoxins through the consumption of mold-infected feeds, which may affect consumer health.

ACKNOWLEDGMENTS

We appreciate the laboratories of the Iraqi Ministry of Science and Technology for its valuable cooperation in this research.