Toxic Effect of Aflatoxins in Dogs Fed Contaminated Commercial Dry Feed: A Review

Co-Occurrence of Aflatoxin B1, Zearalenone and Ochratoxin A in Feed and Feed Materials in Central Italy from 2018 to 2022

Mycotoxin contamination of feed and feed materials represent a serious health hazard. This study details the occurrence of aflatoxin B1 (AFB1), zearalenone (ZEN) and ochratoxin A (OTA) in 826 feed and 617 feed material samples, collected in two Italian Regions (Umbria and Marche) from 2018 to 2022 analyzed using a UPLC-FLD platform. The developed method was validated and accredited (ISO/IEC 17025) with satisfactory accuracy and precision data obtained in repeatability and intralaboratory reproducibility conditions. Feed had a higher incidence of contaminated samples (26%) with respect to feed materials (6%). AFB1 was found up to 0.1045 mg/kg in cattle feeds and 0.1234 mg/kg in maize; ZEN was detected up to 6.420 mg/kg in sheep feed while OTA was rarely reported and in lower concentrations (up to 0.085 mg/kg). Co-contamination of at least two mycotoxins was reported in 0.8% of the analyzed samples. The incidence of above maximum content/guidance level samples was 2% for feed and feed materials while almost 3-fold-higher for maize (5.8%) suggesting how mycotoxin contamination can affect some matrices more than others. Obtained data can be useful to improve official monitoring plans and therefore further raise awareness of this issue between agriculture stakeholders, healthcare entities and non-professionals.

HPLC–MS/MS method for the simultaneous determination of aflatoxins in blood: toxicokinetics of aflatoxin B1 and aflatoxin M1 in rats

Mycotoxins are highly toxic fungal metabolites that can pose health threats to humans and animals. Aflatoxins are a type of mycotoxin produced mainly by Aspergillus flavus and A. parasiticus. A sensitive high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method with multiple reaction monitoring (MRM) modes was developed for the determination of aflatoxins in blood after acetonitrile precipitation extraction. The limits of quantification of aflatoxins ranged from 0.05 to 0.2 ng/mL. Intra-day accuracy ranged from 92 to 111.0%, and intra-day precision (n = 6) ranged from 1 to 8%. Inter-day accuracy and precision were 94.0–102.0% and 2.0–8.0%, respectively. The toxicokinetics of AFB1 and its metabolite AFM1 after a single oral administration (AFB1 1 mg/kg body weight) were studied in male Sprague–Dawley rats. The blood AFB1 and AFM1 profiles could be adequately described by a noncompartmental model. The highest concentration of AFB1 (Cmax 93.42 ± 23.01 ng/mL) was observed with Tmax at 0.15 ± 0.034 h. AFB1 was rapidly metabolized to AFM1 which reached its peak blood concentration (Cmax 53.86 ± 12.12 ng/mL) at 0.33 ± 0.11 h. The HPLC–MS/MS method was simple and sensitive, appropriate for studying the in vivo toxicokinetics of aflatoxins.

Hepatopathy in Victorian dogs consuming pet meat contaminated with indospicine

BACKGROUND

Indospicine is an arginine analogue and a natural toxin occurring only in Indigofera plant species, including Australian native species. It accumulates in the tissues of grazing animals, persisting for several months after ingestion. Dogs are particularly sensitive to indospicine toxicity and can suffer fatal liver disease after eating indospicine-contaminated pet meat.

METHOD

A disease outbreak investigation was launched following notification to Agriculture Victoria of a cluster of 18 dogs displaying acute, severe, hepatopathy in the East Gippsland Shire in June 2021.

RESULTS

Between June and September 2021, 24 pet dogs died, and 40 others experienced liver disease after eating commercially prepared pet meat found to contain indospicine. The investigation identified the toxin in serum and liver samples from affected dogs and at high levels in some samples of pet meat eaten by the dogs. Twenty-six horses that were moved from the Northern Territory and processed at a Pet Meat Processing facility (knackery) in eastern Victoria over a period of 14 days in late May-early June 2021 were identified as the likely source of the indospicine toxin in the pet meat. Pet meat produced by the knackery and on-sold by several retailers was determined to be the cause of the illness and death in the dogs.

CONCLUSION

This is the first report of severe and frequently fatal hepatopathy in dogs in Victoria relating to consumption of pet meat contaminated with indospicine.

Total aflatoxin, aflatoxin B1, ochratoxin A and fuminosin in dry dog food: A risk assessment for dog health

The aim of this study was to measure total aflatoxin (AFT), aflatoxin B₁ (AFB₁), ochratoxin A (OCA) and fumonisin (FUM) concentrations in dry dog feed and to evaluate the risk to animal health posed by their increased levels. A total of 90 dry food samples, which were commercially available to the owner, were collected from different shops in Turkey. Some of the food samples were collected from open packages, from which the dry food was sold in smaller amounts. Using commercial Enzyme-Linked Immunosorbent Assay test kits, all samples were examined for AFT, AFB₁, OCA, and FUM concentrations. High-performance liquid chromatography was used for confirmation of measured parameters in 30 samples. The ELISA tests found AFT, AFB₁, OCA, and FM concentrations (ng g ^-1) as 1.66, 0.64, 2.14, and 87.06, respectively. In terms of risk assessment, consumption of the dry foods, which are contaminated by AFT, AFB₁ and OCA due possibly to the fact that the dry foods are produced from inappropriate raw material or sold in open packages in smaller amounts, poses a significant health risk for dogs. As a result, it is necessary to monitor the mycotoxin load in dry dog food as the use of raw materials of poor quality and selling the feed in smaller amounts from open packages over an uncertain time period predispose the dry feed to the growth of mycotoxin, especially when the storage conditions are favorable.

Assessment of the Potential of a Native Non-Aflatoxigenic Aspergillus flavus Isolate to Reduce Aflatoxin Contamination in Dairy Feed

Aspergillus species can produce aflatoxins (AFs), which can severely affect human and animal health. The objective was to evaluate the efficacy of reducing AF contamination of a non-aflatoxigenic isolate of A. flavus experimentally coinoculated with different aflatoxigenic strains in whole plant (WP), corn silage (CS), immature grains (IG) and in culture media (CM). An L-morphotype of A. flavus (CS1) was obtained from CS in a dairy farm located in the Mexican Highland Plateau; The CS1 failed to amplify the AFs biosynthetic pathway regulatory gene (aflR). Monosporic CS1 isolates were coinoculated in WP, CS, IG and CM, together with A. flavus strains with known aflatoxigenic capacity (originating from Cuautitlán and Tamaulipas, Mexico), and native isolates from concentrate feed (CF1, CF2 and CF3) and CS (CS2, CS3). AF production was evaluated by HPLC and fungal growth rate was measured on culture media. The positive control strains and those isolated from CF produced a large average amount of AFs (15,622 ± 3952 and 12,189 ± 3311 µg/kg), whereas A. flavus strains obtained from CS produced a lower AF concentration (126 ± 25.9 µg/kg). CS1 was efficient (p < 0.01) in decreasing AF concentrations when coinoculated together with CF, CS and aflatoxigenic positive control strains (71.6−88.7, 51.0−51.1 and 63.1−71.5%) on WP, CS, IG and CM substrates (73.9−78.2, 65.1−73.7, 63.8−68.4 and 57.4−67.6%). The results suggest that the non-aflatoxigenic isolate can be an effective tool to reduce AF contamination in feed and to minimize the presence of its metabolites in raw milk and dairy products intended for human nutrition.

Aspergillus flavus and Total Aflatoxins Occurrence in Dairy Feed and Aflatoxin M1 in Bovine Milk in Aguascalientes, Mexico

Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate Aspergillus flavus and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M₁ (AFM₁) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic A. flavus isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn–winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic A. flavus and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.