Toxigenicity and Phylogeny of Aspergillus section Flavi in poultry feed in Iran

Abstract

Background and Purpose: This study was conducted to evaluate the presence of aflatoxigenic strains and level of aflatoxin in poultry feed. Aflatoxigenic strains were investigated in corn and soybean meal as the ingredients of poultry feed, as well as in two types of commercial feed, namely pellet and mash. The gene sequencing was performed to identify the species of Aspergillus section Flavi.
 Materials and Methods: All samples were randomly collected from feed storage silos located in Iran in 2018. The samples were cultured on specialized media for 2 weeks at 28ºC. Identification of Aspergillus section Flavi isolates was based on macro- and microscopic morphological criteria and molecular analysis. The thin-layer chromatography (TLC) was applied to confirm the aflatoxigenic isolates. In addition, the level of aflatoxin B1 (AFB1) produced by these isolates was determined by high-performance liquid chromatography. The strains were subjected to sequence analysis, and Bt2 PCR products were purified by the QIAquick PCR purification kit. At the final stage, the phylogenetic tree was built.
 Results: Among 54 isolates identified as Aspergillus section Flavi, 20 (37%) isolates were found to produce aflatoxin at a range of 11.28±1.18 to 2239.92±92.26 μg/g fungal dry weight. The aflatoxigenic isolates had the frequencies of 45%, 40%, 10%, and 5% in the corn, pellet, soybean meal, and mash samples, respectively. Furthermore, the mean concentrations of AFB1 were significantly higher in the corn samples (707.04±39.05) than that of other poultry feed samples (P<0.05). A total of 34 (63%) isolates were detected as non-aflatoxigenic on the yeast extract-sucrose broth in TLC analysis. The toxigenic isolates produced the highest (2232.62±55.49) and lowest (11.28±1.18) levels of AFB1 in the corn samples, compared to other feedstuffs. Furthermore, the mean level of AFB1 in mash product was 554.09±10.36 μg/g, compared to a mean level of 229.22±11.09 μg/g in pellets. The isolates were randomly selected, sequenced, and then analyzed. Subsequently, the phylogenetic tree of Aspergillus section Flavi was plotted.
 Conclusion: The process of converting raw ingredients to compound poultry feed is more hazardous when there is not enough time and temperature provided to eliminate aflatoxigenic isolates. Therefore, Aspergillus section Flavi in poultry feed can pose a threat to the poultry industry and poultry products, thereby affecting the health status of humans. Unprocessed/processed materials, such as corns and pelleted feed, need further monitoring, especially when conditions are not optimal for destroying the fungus.

Screening of aflatoxin-producing fungi in maize and groundnuts from three regions in Tanzania

“…The predominant Aspergillus species observed during the study was A. flavus (39.1%). This is in agreement with the findings of Fapohunda et al (2012), Davari et al (2015), Fakruddin et al (2015 and Ghaemmaghami et al (2016Ghaemmaghami et al ( , 2020 who reported Aspergillus section flavi to be the predominant species for producing aflatoxins in various feeds. This might have been that A. flavus can adapt to different geographical locations especially the sub-tropical and tropical regions of a country.…”

Aspergillus species contamination in concentrate feeds collected from specialized dairy farms and local markets in selected urban centers of eastern Ethiopia

“…Consistent with the present study, 81.08% of aflatoxigenic Aspergillus species were reported in grain feeds (Salisu et al, 2020). However, a lower frequency of aflatoxigenic Aspergillus species was reported in dairy feed (52%) from Katsina State of Nigeria, animal feed from Algeria (68.4%), and dairy feed (25%) obtained from the Fulani province in South Africa (Ghaemmaghami et al, 2016;Salisu et al, 2020). Moreover, a comparable aflatoxigenic Aspergillus species (70%) was found in poultry feeds collected from Tehran and Alborz provinces (Ghaemmaghami et al, 2018).…”

Aflatoxin levels in poultry feed: a comparison of mash and pellet forms

“…During the transfer of pellets from the Pelletizer machine to the cooling machine, exposure to saprophytic Aspergillus in the environment can lead to growth during storage. Malfunctions in the equipment can also impact the feed preparation process, potentially affecting the overall quality ( Ghaemmaghami et al, 2020 ).…”

“… Ghaemmaghami et al (2016) conducted a study to determine the levels of fungal contamination in poultry feed. The research identified a total of 384 fungal isolates across different feed ingredients, including corn (124 isolates), soybean meal (92 isolates), mash feed (72 isolates), and pellet feed (96 isolates).…”