Mycotoxicological quality of equine feed in argentina.

GONZÁLEZ PEREYRA M.L.,; TISERA J.,; MANTEÑA C.,; CAVAGLIERI L.R.,; KELLER K.M.,; ROSA C.A.R.,; MAGNOLI C.,; DALCERO A.M.

Moscow, Russia.

Congreso; Congress of World Equine Veterinary Association.; 2008

Most feedstuffs, cereal crops and other agricultural commodities are very susceptible to contamination by molds able to produce mycotoxins. Mycotoxins are toxic secondary metabolites that can cause adverse effects such as carcinogenesis, teratogenesis, nephrotoxicity and immunosuppression, leading to numerous pathologies and consequent economic losses (Hussein and Brasel 2001). Aspergillus and Fusarium are the most frequently genera involved in animal and human cases of mycotoxicoses. In equines, mycotoxicoses are mainly related to corn based feedstuffs consumption contaminated with fumonisins (FBs) produced by F. verticillioides. These mycotoxins are responsible for equine leukoancephalomalacia (ELEM), an acute and fatal neurological disease characterized by neurotoxic symptoms — including loss of feed consumption, lameness, ataxia, oral and facial paralysis, head pressing, and recumbence (Marasas et al. 1988). More than one mycotoxin may exist simultaneously in a particular commodity or ingredient. Generally, the effects of these toxins tend to add up in synergic response, increasing the risk and hazard to animal health and productivity (D'Mello et al. 1999). Aflatoxins (AFs) are mycotoxins produced by A. flavus and A. parasiticus. Aflatoxin B1 (AFB1) is the most frequently detected and it has been described as the strongest biologically synthesized hepatocarcinogenic substance that can affect humans and animals (Rosa et al. 1996). Checking the mycological and mycotoxicological quality, control of feedstuffs and commodities destined to equine consumption is critical for improving animal production and performance. The purposes of this study were:1) to determine the natural incidence of Aspergillus spp. and Fusarium spp. and the distribution of potential mycotoxin producers, 2) to detect and quantify FBs and AFs in equine feedstuffs. Thirty samples of 21 different commercial feeds were randomly collected from five different studs located in Rio de Janeiro State, from October 2005 to March 2006. Feeds were subdivided as intended for light effort, middle effort and intense effort horses. Analysis of the mycobiota was made by the plate dilution spread method onto dichloran rose bengal chloranphenicol agar (DRBC), dichloran glycerol 18% agar (DG18) (Pitt & Hocking 1997) and Nash-Snyder culture media. Total fungal counts were expressed as CFU/g. The isolation frequency (%) of fungal genera/species was determined. Taxonomic identification of total fungal genera and Aspergillus and Penicillium species was done according to Pitt and Hocking (1997), Klich (2002), Samson et al. (2000) and Nelson et al. (1983). Mycotoxins determination was done using a commercial ELISA kits (Beacon Analytical Systems Inc.) Total fungal counts were similar on both DRBC and DG18 media. They ranged from not detected (ND) to 3.8 x 106 in  light effort, ND to 2.2 x 104 in middle effort and from ND to 1.0 x 103 CFU/g in intense effort feed. Penicillium (48%) and Aspergillus (37.3%) were the most frequently isolated genera, followed by Monilliella spp. (5.33%), Cladosporium spp. (5.33%), Fusarium spp. (1.33%), Rhizopus spp. (1.33%) and Mucor spp. (1.33%). Three Aspergillus species were identified. Aspergillus niger was the prevalent species (39.29%) followed by A. flavus (14.29%) and A. ustus (3.57%). Eigth Penicillium species were identified as P. fellutanum (13.89%), P. corylophilum (8.33%), P. minioluteum (5.56%), P. raistrickii (2.78%), P. citrinum (2.78%), P. commune (2.78%), P. miczynskii (2.78%) and P. brevicompactum (2.78%). The telomorphic phases Eurotium spp. (28.57%) and Eupenicillium spp. (2.78%) were also isolated. A percentage of 63.33 of the samples showed FBs contamination with an average level of 1.44 ± 1.93 ppm (Figure 1a). All samples (100%) showed AFs contamination with an average level of 8.36 ± 9.80 ppb (Figure 1b).