Effect of Dietary Zearalenone and Calibrin® Z on Nutrients Digestibility, Oxidative Stress, and Immune Response in Pigs

The incidence of zearalenone (ZEA) contamination in animal feeds is increasing in many countries. Therefore, understanding the biological effects of ZEA in addition to its estrogenic effects in pigs becomes important for hog producers.

Two experiments (EXP) were conducted to investigate the effects of dietary ZEA in pigs and the potential of ameliorating those effects using Calibrin-Z (CAZ), a thermally processed calcium montmorillonite. In EXP 1, 20 postweaning gilts were used and allotted into 4 treatments with addition of 0, 1, 2, or 3 ppm ZEA to a basal diet and fed for 21 d. In EXP 2, 36 pigs were allotted into 6 treatments and fed diets containing {ZEA ppm/CAZ %}: {0/0}, {0/0.1}, {1/0}, {1/0.1}, {1/0.2}, and {1/0.4} for 21 d. In both EXP, pigs consumed feed ad libitum and were allowed to access water freely. Pigs were housed individually; therefore, individual pig was experimental unit. In EXP 1, fecal and urine samples were collected daily from d-3 to d-18 for calculation of apparent digestibility. Reproductive organs were isolated and relative weight determined. Blood was withdrawn at the beginning of each EXP and serum, and liver samples were collected at the end of both trials. Malondialdehyde (MDA), glutathione peroxidase (GPX), and total superoxide dismutase (TSD) were measured in the serum and liver. Serum antibody titer production in response to classical swine fever (CSF) vaccination was determined at d-1 and d-21 in both studies.

In EXP 1, reproductive organ weight increased as dietary ZEA increased. Overall dry matter (DM), organic matter (OM), crude protein (CP), and energy (GE) digestibility all decreased linearly (P < 0.05) as dietary ZEA increased. For instance, the CP digestibility decreased when dietary ZEA increased from 0 to 1, 2, 3 ppm, with values of 86, 83, 82, and 81%, respectively. However, when daily digestibility was determined at d-18 there was a 6% difference observed between 0 ppm and 1, 2, 3 ppm ZEA. Gross energy digestibility showed a similar trend with an overall average of 2% difference between 0 and 3 ppm ZEA. Serum and liver MDA increased linearly as dietary ZEA increased; GPX and TSD enzyme activities decreased as dietary ZEA increased (P < 0.01). Antibody titer response to CSF vaccination was reduced in pigs fed 2 or 3 ppm ZEA but was not different between pigs fed the 0 and 1 ppm ZEA diets. In EXP 2, pigs fed 1 ppm ZEA without CAZ showed higher MDA (P < 0.01) and lower GPX and TSD (P < 0.05) in the serum and liver. And the reduced enzyme and increased MDA concentrations were ameliorated by CAZ additions. Serum IgG followed a similar pattern as serum GPX and TSD in that 1 ppm ZEA decreased the IgG and the addition of CAZ improved reduced IgG. Antibody titer response to CSF vaccination was not different between 0 and 1 ppm ZEA; however, addition of 0.1% CAZ to the basal diet increased the titer response (P < 0.05) to the vaccination.

In conclusion, 1 to 3 ppm dietary ZEA not only affected reproductive traits in pigs but also showed negative impact on nutrient digestibility, increased cell oxidative stress, and reduced antibody titer to vaccine, and total IgG. Supplementation of 0.1 to 0.4% Calibrin-Z can ameliorate the detrimental effects of ZEA in pigs.

Keywords: Zearalenone, Calcium Montmorillonite, Nutrient Digestibility, Oxidation, Immunity.