Enzymatic degradation of ochratoxin A in the gastrointestinal tract of piglets

Lay Summary Ochratoxin A (OTA) is a potent toxin frequently present in animal feeds, which accumulates in the animal tissues for human consumption. This results in critical animal welfare issues, as well as food safety issues. To the best of our knowledge, the present study is the first to show that OTA can be degraded by an enzyme supplemented with pigs' feed. In the pig gut, this enzyme successfully breaks down the toxic OTA molecule into a nontoxic form that is excreted through urine and feces, which is applicable in supporting the pig's health, welfare, and productivity as well as assuring the safety of the pig meat for human consumption. Ochratoxin A is commonly present in swine feed. This study is the first to show that an enzyme can break down the mycotoxin ochratoxin A in the gastrointestinal tract of piglets. The use of enzymes as a feed additive will allow for mitigating the risk associated with contamination of ochratoxin A in swine feeds, thus improving animal welfare and food safety. Animal feeds are often contaminated with ochratoxin A (OTA), a potent natural mycotoxin hazardous to animal and human health that accumulates in blood and tissues. To the best of our knowledge, this study is the first to investigate the in vivo application of an enzyme (OTA amidohydrolase; OAH) that degrades OTA into the nontoxic molecules phenylalanine and ochratoxin & alpha; (OT & alpha;) in the gastrointestinal tract (GIT) of pigs. Piglets were fed six experimental diets over 14 days, varying in OTA contamination level (50 or 500 & mu;g/kg; OTA50 and OTA500) and presence of OAH; a negative control diet (no OTA added) and a diet containing OT & alpha; at 318 & mu;g/kg (OT & alpha;318). The absorption of OTA and OT & alpha; into the systemic circulation (plasma and dried blood spots, DBS), their accumulation in kidney, liver, and muscle tissues, and excretion through feces and urine were assessed. The efficiency of OTA degradation in the digesta content of the GIT was also estimated. At the end of the trial, accumulation of OTA in blood was significantly higher in OTA groups (OTA50 and OTA500) in comparison to enzyme groups (OAH50 and OAH500, respectively). The supplementation of OAH explicitly reduced the absorption of OTA (P < 0.005) into plasma by 54% and 59% (from 40.53 & PLUSMN; 3.53 to 18.66 & PLUSMN; 2.28 ng/mL in piglets fed the 50 & mu;g OTA/kg diets and from 413.50 & PLUSMN; 71.88 to 168.35 & PLUSMN; 41.02 ng/mL in piglets fed the 500 & mu;g OTA/kg diets, respectively) and in DBS by 50% and 53% (from 22.79 & PLUSMN; 2.63 to 10.67 & PLUSMN; 1.93 ng/mL in piglets fed the 50 & mu;g OTA/kg diets and from 232.85 & PLUSMN; 35.16 to 105.71 & PLUSMN; 24.18 ng/mL in piglets fed the 500 & mu;g OTA/kg diets, respectively). The OTA concentrations in plasma were positively associated with the OTA levels detected in all tissues analyzed; adding OAH reduced OTA levels in the kidney, liver, and muscle (P < 0.005) by 52%, 67%, and 59%, respectively. The analysis of GIT digesta content showed that OAH supplementation led to OTA degradation in the proximal GIT where natural hydrolysis is inefficient. Overall, the data of present in vivo study demonstrated that supplementation of swine feeds with OAH successfully reduced OTA levels in blood (plasma and DBS) as well as in kidney, liver, and muscle tissues. Therefore, an approach to use enzymes as feed additives might be most promising to mitigate the harmful effects of OTA on the productivity and welfare of pigs and at the same time improving the safety of pig-derived food products.

Automated summary

By supplementing pigs' feed with an enzyme, it is possible to degrade the toxic Ochratoxin A (OTA) into a non-toxic form that can be excreted, thus improving pig health, welfare, productivity, and food safety.