An investigation into the analytical, cytotoxicity and immunotoxicity of mycotoxins found in commercially available pelleted pet foods in Durban, South Africa.
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Date
2018
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Abstract
Introduction:
Dry pelleted dog food in the South African market is available via supermarket, pet stores
(standard brands - SB) and veterinary channels (premium brands-PB). Similarly, cat food were
viewed in two market segments.
Methodology:
Representative feeds from both categories were analysed for four main mycotoxins viz.
aflatoxins (AF), fumonisin (FB), ochratoxin A (OTA), and zearalenone (ZEA) using standard
well-described extraction, characterisation and quantitation processes.
Results:
All foods showed contamination with fungi (mainly Aspergillus flavus, Aspergillus fumigatus
and Aspergillus parasiticus) and mycotoxins (the most prevalent being aflatoxins and
fumonisins), irrespective of the brand. This study determined the immunotoxicity of extracts
from pelleted dog and cat feed for mycotoxins. Isolated dog peripheral blood mononuclear cells
(PBMCs) were treated with feed extracts to determine mitochondrial function, oxidative stress,
and markers of cell death using luminometry and flow cytometry. Glutathione was significantly
depleted by SB extracts. Markers of apoptosis and necrosis were elevated by both SB and PB
feeds when compared to controls, with SB extracts being significantly higher than PB. ATP
levels decreased with increased mitochondrial depolarization in cells that were exposed to both
feed extracts with SB showing the greatest differences when compared to the control. Cat
peripheral blood mononuclear cells (PBMCs) were isolated and treated with various feed
extracts to determine oxidative stress (TBARS and GSH assay), mitochondrial integrity and
cell death (Luminometry and Flow cytometry). Both PB and SB extracts showed significantly
decreased ATP levels and increased mitochondrial depolarization except for the PB acid
fraction. Lipid peroxidation was significantly increased in both PB and SB extracts with a
concomitant decrease in GSH levels. Phosphatidylserine externalization and necrosis levels
were increased in both PB and SB extracts when compared to the control. Executioner
caspases-3/7 was also elevated following extract exposure except for the PB acid fraction.
Conclusion:
There were high levels of fungal contamination and mycotoxins in both categories of feed,
regardless of the notion that higher priced PB’s were of a higher quality.
Description
Doctoral Degree. University of KwaZulu-Natal, Durban.