Mycoflora, aflatoxigenic strains of Aspergillus section Flavi and aflatoxins in fish feed

Abstract

Commercial feedstuffs are an important component in a modern aquaculture industry. Mycotoxin contamination of fish feeds represents a hazard to aquatic animals and human health. This study aimed to determine the mycoflora, aflatoxigenic strains of Aspergillus section Flavi, and occurrence of aflatoxins in fish feed samples. A total of 86 fish feed samples consisting of pellet, extruder, and scramble samples were collected from feed processing industries and fish farms in Iran. Identification of fungi, in vitro production of aflatoxins by Aspergillus section Flavi strains, and analysis of aflatoxins were done according to standard and established methods. The mean total fungal counts ranged between 2.16 and 4.74 log cfu/g in samples; and 2 samples (2.33%) exceeded the hygienic quality limit, i.e. 4 log cfu/g. Aspergillus was the predominant detected genera followed by Penicillium and Fusarium. Among the Aspergillus species, Aspergillus flavus was the most prevalent species, followed by Aspergillus parasiticus, Aspergillus niger, and Aspergillus ochraceus. All the A. parasiticus isolates and 48.1% of the A. flavus isolates produced aflatoxins in vitro. Contamination with aflatoxins were detected in 58 feed samples (67.5%), ranging between 0.46 and 68.5 µg/kg. The results revealed that the frequency of contamination with aflatoxins and prevalence of aflatoxigenic fungi in such a level can be a potential hazard for the aquaculture industry and human health. Regular monitoring of mycotoxins specially aflatoxins in feed supply chain can improve the situation through reducing economic losses and minimizing hazards to the public health.

Co-Occurrence and Levels of Mycotoxins in Fish Feeds in Kenya

“…Similarly, Marijani et al [ 33 ] reported higher mean levels (>90.1 µg/kg) and ranges (<2.0–806.9 µg/kg) in fish feeds from the Lake Victoria region in Kenya than in the current study possibly due to a lower LOD of 2 µg/kg. Other authors have reported varied prevalences, levels and ranges of various AFs in fish feed from different parts of the world [ 29 , 34 , 62 , 81 , 82 , 83 ]. In another study, Marijani et al [ 34 ] have reviewed the toxic effects of AFs reported in assorted fish species ranging from reduced weight gain, reduced liver function to fish mortalities.…”

Assessment of the Presence of Total Aflatoxins and Aflatoxin B1 in Fish Farmed in Two Cameroonian Localities

“…The significant difference observed between the AF and AFB 1 concentrations in kanga and tilapia which are both farmed in the same pond also confirmed the hypothesis that the metabolic activities involved in the storage and/or elimination of mycotoxins in fish tissue vary with the fish species. The presence of AFs and AFB 1 in fish farmed in Cameroonian localities is of greatest concern because they can lead to negative effects on the development of fish such as stunting, liver damage, immunosuppression [ 26 ], decrease in growth performance, and increase susceptibility to disease and high mortality [ 27 ]. Rahman et al [ 28 ] pointed out the significant reductions in the total serum proteins, albumins, and globulins caused by the presence of AFB 1 in Nile tilapia.…”

Multi-Mycotoxin Occurrence in Dairy Cattle Feeds from the Gauteng Province of South Africa: A Pilot Study Using UHPLC-QTOF-MS/MS

“…Mngadi et al [ 3 ], also mentioned similar ratios in preliminary work done on South African animal feeds. Such variations may be attributed to the complex differences in the aetiology in the production of the toxins with a generally accepted understanding that AFB 1 and AFB 2 are produced by fungal species belonging to the A. flavus while A. paraciticus produces all the principal four AFs (AFB 1 , AFB 2 , AFG 1 and AFG 2 ) [ 18 , 19 , 20 , 21 ]. Moreover, experimental studies on the issue indicate that AFB and AFG ratios are largely influenced by conditions within ecological niches that parent fungal species occur [ 16 ].…”