Opinion of the Scientific Panel on contaminants in the food chain [CONTAM] related to ochratoxin A (OTA) as undesirable substance in animal feed

Abstract

SUMMARYOchratoxin A is a mycotoxin produced by several fungi of the genera Aspergillus and Penicillium, principally P. verrucosum in temperate climates and A. ochraceus in warm regions. In animal feed materials the toxin is found most commonly in cereals (rye, barley, maize, and wheat) and to a lesser degree in peanuts and soybean. Toxin production usually occurs during storage and control of formation of the toxin requires adequate drying of grains prior to storage under conditions where water activity does not rise in localised "hot spots". The distribution of ochratoxin A in stored grains is very heterogeneous, making analysis and dietary exposure assessment of farm animals difficult. However, exposure of animals may also be assessed from analysis of blood levels. Ochratoxin A is a potent renal toxin in all animal species investigated as of yet and has been causally associated with nephropathy in pigs and poultry. Exposure to nephrotoxic doses is associated with renal tumours in laboratory rodents but no data on carcinogenicity are available in other animal species. Ochratoxin A is also immunotoxic and teratogenic but usually at higher than nephrotoxic doses. Pigs, dogs and poultry are particularly sensitive to the nephrotoxicity and a no-observed-adverse-effect level has not been established in pigs or dogs; ruminants are less sensitive due to degradation of ochratoxin A to the less toxic ochratoxin α by the rumen microflora. Upon absorption from the gastro-intestinal tract, ochratoxin A binds to serum proteins resulting in considerable variation in elimination half-lives across species depending on the affinity and degree of protein binding. It is only metabolised to a small extent systemically. Accumulation occurs in blood, liver and kidney, and significant lower residue concentrations are found in muscle tissue, fat and milk. Carry-over into eggs has been demonstrated under experimental conditions using high toxin concentrations. Multiple source exposure assessment indicates that the overall contribution of animal products to human exposure does generally not exceed 3 -10 %.

Factors during Production of Cereal-Derived Feed That Influence Mycotoxin Contents

“…Due to adverse health effects in animals (shown in Table 1 ), the presence of mycotoxins in feed is undesired and should be as low as possible. The occurrence of adverse effects in animals is dose-dependent, which can differ per mycotoxin and per animal species and/or age class [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. As an example, no effect was observed with regards to vulva appearance and uterus weight in piglets at a dose of 10.4 µg/kg body weight/day of zearalenone (ZEN), while a no observed adverse effect level (NOAEL) of 40 µg/kg body weight/day was established for ZEN in mature female pigs based on prolonged cycling [ 11 ].…”

“…The majority of mycotoxins are thermally stable contaminants, and heating of feed materials can hardly reduce their concentrations therein [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. However, during the production of feed, processing leads to dilution of mycotoxin concentrations and/or redistribution of mycotoxins in the different fractions of the processed product.…”

Feedborne Mycotoxins Beauvericin and Enniatins and Livestock Animals

“…Most, but not all, of these mycotoxins are produced by the Fusarium species. Although these mycotoxins are significant contaminants when entering the food chain directly via food of plant origin, they are not considered relevant in food of animal origin because their carry-over from feed to animal-derived food products is negligible [9][10][11][12]. However, Fusarium species are also responsible for the production of minor mycotoxins, namely, enniatins and beauvericin, which are currently in the center of interest because of the wide range of their biological activities, as described in details bellow.…”

Determination of Aflatoxins and Ochratoxin a in Animal Liver using HPLC-FD Method with Immunoaffinity Column Clean-Up

“…Consumption of a mycotoxin-contaminated diet may have direct consequences on animal health and economic impact as well. This includes reduced weight gain and reproductive capacities, feed refusal and poor feed conversion, less meat and egg production, increased disease incidence (due to immunesuppression) and lower productivity (1)(2).…”