Mycobiota and aflatoxins in raw materials and pet food in Brazil

Natural mycotoxin contamination in dog food: A review on toxicity and detoxification methods

Nowadays, the companion animals (dogs or other pets) are considered as members of the family and have established strong emotional relationships with their owners. Dogs are long lived compared to food animals, so safety, adequacy, and efficacy of dog food is of great importance for their health. Cereals, cereal by-products as well as feedstuffs of plant origin are commonly employed food resources in dry food, yet are potential ingredients for mycotoxins contamination, so dogs are theoretically more vulnerable to exposure when consumed daily. Aflatoxins (AF), deoxynivalenol (DON), fumonisins (FUM), ochratoxin A (OTA), and zearalenone (ZEA) are the most frequent mycotoxins that might present in dog food and cause toxicity on the growth and metabolism of dogs. An understanding of toxicological effects and detoxification methods (physical, chemical, or biological approaches) of mycotoxins will help to improve commercial ped food quality, reduce harm and minimize exposure to dogs. Herein, we outline a description of mycotoxins detected in dog food, toxicity and clinical findings in dogs, as well as methods applied in mycotoxins detoxification. This review aims to provide a reference for future studies involved in the evaluation of the risk, preventative strategies, and clear criteria of mycotoxins for minimizing exposure, reducing harm, and preventing mycotoxicosis in dog.

Contamination of Pet Food with Mycobiota and Fusarium Mycotoxins-Focus on Dogs and Cats

A wide range of pet food types are available on the market; the dominant type is dry food formulated in croquets. One of the most common ingredients of dry food are cereals—vectors of harmful mycotoxins posing the risk to pet health. In this study, 38 cat and dog dry food samples available on the Polish market were investigated. Morphological and molecular methods were applied to identify fungal genera present in pet food. Quantification of ergosterol and Fusarium mycotoxins: Fumonisin B₁, deoxynivalenol, nivalenol, and zearalenone were performed using high performance liquid chromatography. Obtained results indicated five genera of mycotoxigenic fungi: Alternaria sp., Aspergillus sp., Cladosporium sp., Penicillium sp., and Fusarium sp., including Fusarium verticillioides and Fusarium proliferatum. Ergosterol and mycotoxins of interest were detected in both cat and dog food samples in the amounts ranging from 0.31 to 4.05 µg/g for ergosterol and 0.3–30.3, 1.2–618.4, 29.6–299.0, and 12.3–53.0 ng/g for zearalenone, deoxynivalenol, nivalenol, and fumonisin B₁, respectively. The conclusion is the presence of mycotoxins in levels much lower than recommended by EU regulations does not eliminate the risk and caution is advised concerning that long-term daily intake of even small doses of mycotoxins can slowly damage pet’s health.

Fusarium Species and Mycotoxins Contaminating Veterinary Diets for Dogs and Cats

Veterinary diets are intended for diseased animals and may contain cereal grains, mainly maize and/or wheat. These, in turn, are often infected with pathogens of the Fusarium genus, which are able to produce numerous harmful mycotoxins. Forty-two samples of veterinary diets for dogs and cats were analyzed for the presence of Fusarium species and mycotoxins. Species were identified using molecular methods and the ergosterol and mycotoxins (fumonisin B₁, deoxynivalenol, nivalenol and zearalenone) were quantified using HPLC methods. Two Fusarium species were identified: Fusarium proliferatum and Fusarium verticillioides. The highest concentrations of fumonisin B₁, deoxynivalenol, nivalenol and zearalenone were 74.83, 2318.05, 190.90, and 45.84 ng/g, respectively. Only 9.5% of the samples were free from Fusarium mycotoxins. The acceptable limits of mycotoxin content in animal feed, specified by the EU regulations, were not exceeded in any of the samples tested. The mean mycotoxin content in veterinary diets for cats was lower than for dogs. Thus, it is recommended that veterinary diets are examined, since the mycotoxin contamination pose additional risk to animal health. The knowledge on Fusarium occurrence in veterinary diets is scarce and as far as we are aware this is the first report concerning the occurrence of Fusarium spp. and their important secondary metabolites—mycotoxins—in different types of veterinary diets for companion animals in Poland.

Pediococcus acidolactici and Pediococcus pentosaceus isolated from a rainbow trout ecosystem have probiotic and ABF1 adsorbing/degrading abilities in vitro

Probiotics are being used in biological control of bacterial pathogens, as an alternative to antibiotics, to improve health and production parameters in fish farming. Fish farming production is severely affected by aflatoxins (AFs), which are a significant problem in aquaculture systems. Aflatoxins exert substantial impact on production, causing disease with high mortality and a gradual decline of reared fish stock quality. Some aspects of aflatoxicosis in fish, particularly its effects on the gastrointestinal tract, have not been well documented. The aim of the present study was to evaluate probiotic properties of lactic acid bacterial (LAB) strains isolated from rainbow trout intestine and feed. Moreover, AFB₁-binding and/or degrading abilities were also evaluated to assess their use in the formulation of feed additives. Growth at pH 2, the ability to co-aggregate with bacterial pathogens, inhibition of bacterial pathogens, and determination of the inhibitory mechanism were tested. Aflatoxin B₁ (AFB₁) adsorption and degradation ability were also tested. All strains were able to maintain viable (10⁷ cells ml^-1) at pH 2. Pediococcus acidilactici RC001 and RC008 showed the strongest antimicrobial activity, inhibiting all the pathogens tested. The strains produced antimicrobial compounds of different nature, being affected by different treatments (catalase, NaOH and heating), which indicated that they could be H₂O_2, organic acids or proteins. All LAB strains tested showed the ability to coaggregate pathogenic bacteria, showing inhibition percentages above 40%. Pediococcus acidilactici RC003 was the one with the highest adsorption capacity and all LAB strains were able to degrade AFB₁ with percentages higher than 15%, showing significant differences with respect to the control. The ability of some of the LAB strains isolated in the present work to compete with pathogens, together with stability against bile and gastric pH, reduction of bioavailability and degradation of AFB₁, may indicate the potential of LAB for use in rainbow trout culture.

In vitro aflatoxin B1 binding capacity by two Enterococcus faecium strains isolated from healthy dog faeces

AIM

This study evaluated the binding capacity of aflatoxin B1 (AFB1 ) by two Enterococcus faecium strains (MF4 and GJ40) isolated from faeces from healthy dogs.

MATERIALS AND METHODS

The binding assay was performed using 50 and 100 ppb of AFB1 analysing the effects of the viability, incubation time and pH on AFB1 binding. Binding stability was determined by washing three times the bacteria-AFB1 complexes with phosphate buffer saline.

RESULTS

Both GJ40 and MF4 strains have the ability to remove AFB1 from aqueous solution. Viable cells were slightly more effective in AFB1 binding than nonviable ones for both strains. Enterococcus faeciumGJ40 removes 24-27% and 17-24%, and Ent. faeciumMF4 removes 36-42% and 27-32% of AFB1 (50 and 100 ppb, respectively) throughout a 48 h incubation period. In general, the removal of AFB1 was highest at pH 7.00 for both strains. The stability of the bacteria-AFB1 complex formed was found to be high (up to 50% of AFB1 remained bounded in bacterial cell after three washes with phosphate buffered saline).

CONCLUSION

The Ent. faecium strains assayed are capable of removing AFB1 under different conditions in vitro.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first AFB1 binding assay performed with Ent. faecium strains isolated from dog faeces, being an interesting strategy for AFB1 decontamination of pet food.

Inhibitory properties of Enterococcus spp. isolated from faeces of healthy dogs

The aim of the present study was to evaluate the inhibitory effect by the cross-streak method of nine Enterococcus faecium strains isolated from faeces of healthy dogs and their treated and non-treated cell-free supernatant (CFS) by the well-diffusion test on the growth of potentially pathogenic bacteria isolated from clinical cases and aflatoxigenic Aspergillus section Flavi and the consequent aflatoxin B1 (AFB1) production. Results obtained from the cross-strake assay showed that E. faecium MF1, GJ18 and GJ40 presented the major inhibitory activity against all pathogenic strains assayed; E. faecium GJ40 produced the larger inhibitory zones (26-27 mm). Well-diffusion test results showed that the majority of the enterococci strains CFS had antimicrobial activity against the pathogenic microorganisms, especially on Gram negative indicators. Cell-free supernatant of E. faecium GJ40 was the one that produced the largest inhibition zones (14 to 21 mm) in the majority of the indicator microorganisms assayed. All supernatants treated with 10 N NaOH (pH6) showed no inhibitory effect on the indicator strain assayed. With respect to fungal inhibition, any of the CFS assayed significantly inhibited the Aspergillus strains growth. But, in general, all CFS reduced AFB1 production from 8 to 87%. The results demonstrate that enterococci isolated from healthy dog feaces produce substances with the capacity to inhibit some potential pathogenic bacteria growth and the capacity of inhibiting or reducing the AFB1 production in vitro.

Effect of acid lactic bacteria isolated from faeces of healthy dogs on growth parameters and aflatoxin B1 production by Aspergillus species in vitro

The aim of the present study was to evaluate the inhibitory effect of Enterococcus faecium and Lactococcus lactis subsp. lactis isolated from faeces of healthy dogs on (i) lag phase, (ii) growth rate, and (iii) aflatoxin B1 production by Aspergillus section Flavi on in vitro assays. Thirteen lactic acid bacteria (LAB) isolates were used as antagonist microorganisms. Antagonistic activity was assayed against four potentially aflatoxigenic Aspergillus section Flavi isolates: A. flavus (AF210 and AF281), A. parasiticus (AP245) and A. parasiticus (NRRL 2999). In general, the longest lag phases of Aspergillus isolates were obtained with E. faecium GJ40. Respecting the growth rate, no significant reduction was found in this parameter in the interaction assays with A. flavus and antagonist isolates respecting the control. While in A. parasiticus a significant reduction in growth rate was only observed in the interaction among reference strain and E. faecium MF5 isolate (p < 0.05). In general, AFB1 production was reduced by most of the LAB isolates assayed, except for E. faecium GJ18, GJ20, MF3 and MF4. This study provides the first data about the antiaflatoxigenic activity of autochthonous LAB isolated from dog faeces.

Aflatoxigenic fungi and aflatoxin B1 in commercial pet food in Brazil

The aims of this study were to determine the aflatoxigenic mycoflora and the incidence of aflatoxin B1 in commercial samples of ready dog food. This in turn demonstrated the ability of the Aspergillus flavus and Aspergillus parasiticus strains to produce aflatoxin B1. 180 samples (standard, premium and super premium) were collected. Aspergillus was the prevalent genera followed by Penicillium and Fusarium. A. flavus and A. parasiticus were the prevalent species. All A. flavus and A. parasiticus strains from super premium samples were able to produce aflatoxin B1, whereas toxigenic strains isolated from standard and premium samples varied from 80 to 100%. A high percentage of ready pet food contaminated by toxigenic species from section Flavi was found and aflatoxin B1 levels were detected. The fungal counts from the three kinds of feed did not exceed the proposed value (1×104 cfu/g) and none of the samples exceeded the aflatoxin B1 recommended level (20 ng/g). The presence of A. flavus and A. parasiticus with aflatoxigenic ability could be a potential risk for production of AFB1 in feedstuffs when environmental storage conditions are not adequate.