Susceptibility to Secondary Bacterial Infections in Growing Rabbits Exposed to Ochratoxin A and Protected or Not by Herbal Supplements

The protective effects of the herbal feed supplements <i>Silybum marianum</i>, Silymarin, <i>Withania somnifera,</i> and <i>Centella asiatica</i> against ochratoxin A (OTA) toxicity were studied in 48 New Zealand White rabbits (37-day-old) during an 80-day experiment. OTA was given at 2 ppm, whereas <i>Silybum marianum</i>, Silymarin, <i>Withania somnifera</i>, and <i>Centella asiatica</i> were given at feed levels of 5000 ppm, 25,000 ppm, 4000 ppm, and 4600 ppm, respectively. All rabbits were immunized against Rabbit Hemorrhagic Disease Virus (RHDV). OTA was found to induce an immunosuppressive effect on the humoral immune response. Reliable protection against OTA-provoked immunosuppression by Silimarin and <i>Withania somnifera</i> was found. The OTA-induced immunosuppression was responsible for secondary bacterial infection (pasteurellosis) and the death of two rabbits from the OTA-exposed group and one rabbit each from the groups protected with <i>Silybum marianum</i> and <i>Centella asiatica</i>. A decreased body weight was found in rabbits exposed to OTA, but the decrease was slighter in the rabbits protected with herbal supplements. The target organs damaged by OTA exposure were the liver, kidneys, and spleen, while weaker lesions were found in other internal organs, except in the cases of secondary pasteurellosis, in which the strongest damage was found in the lung. All investigated herbal supplements appeared to have stronger protective effects against OTA-induced damage to the kidneys and liver, with slightly protective effects observed in the lungs, myocardium, spleen, brain, intestine, testicles, and ovaries.