Ochratoxin A (OTA) is a mycotoxin produced by some Aspergillus and Penicillium fungi and it induces several toxic effects. The present Ph.D. thesis investigated: 1) an in vitro pre-natal exposure model, by analyzing the effects of acute oocyte exposure to OTA on oocyte maturation and embryo development in the sheep; 2) an in vivo pre and post-natal exposure model, through examining OTA levels in feed, blood and milk samples of jennies and related foals. The sheep was used as a relevant model for human reproductive medicine. The donkey was used as suitable model to follow the route of natural exposure from feed to jennies during pregnancy and in foals after delivery. Moreover, donkey milk has high nutritional value in human diet. Ovine cumulus-oocyte complexes (COCs) were exposed to OTA during in vitro maturation (IVM) in a micro-to nanomolar range. After IVM, some oocytes were analyzed for Metaphase II (MII) rate, while others underwent in vitro fertilization (IVF) and embryo culture up to day7. Micromolar concentrations had adverse effects on cumulus expansion and viability, oocyte nuclear and cytoplasmic maturation and embryo development. At nanomolar concentrations, no adverse effects were found on COC viability and integrity whereas blastocyst had higher nuclear apoptosis. In donkey feed, toxin concentration was up to 2.7 ng/g with an incidence of 32%, far below the guidance values of OTA in feed materials reported by EU Recommendation 2016/1319. In jennies, the incidence of positive blood samples was 73% (median value= 114 ng/L; range 51 to 6000 ng/L). In foals, the incidence of positive blood samples was 50% (median value= 136 ng/L; range 79 to 4030 ng/L). No placental transfer of OTA was observed in all tested jennies and no influence on 2 pregnancy length and health of foals was observed. In milk, the incidence of positive samples was 36% (range 17 to 82 ng/L). In conclusion, in sheep, in vitro exposure to OTA affected oocyte function and embryo development; in jennies, no placental passage was observed but OTA passed from feed to milk through the blood. Effects on female fertility and newborn health need to be further investigated.
Effects of dietary exposure to Ochratoxin A (OTA) mycotoxin below/ around guidance values on embryo/fetal development and pregnancy success
Shafaq asif
2020-01-01
Abstract
Ochratoxin A (OTA) is a mycotoxin produced by some Aspergillus and Penicillium fungi and it induces several toxic effects. The present Ph.D. thesis investigated: 1) an in vitro pre-natal exposure model, by analyzing the effects of acute oocyte exposure to OTA on oocyte maturation and embryo development in the sheep; 2) an in vivo pre and post-natal exposure model, through examining OTA levels in feed, blood and milk samples of jennies and related foals. The sheep was used as a relevant model for human reproductive medicine. The donkey was used as suitable model to follow the route of natural exposure from feed to jennies during pregnancy and in foals after delivery. Moreover, donkey milk has high nutritional value in human diet. Ovine cumulus-oocyte complexes (COCs) were exposed to OTA during in vitro maturation (IVM) in a micro-to nanomolar range. After IVM, some oocytes were analyzed for Metaphase II (MII) rate, while others underwent in vitro fertilization (IVF) and embryo culture up to day7. Micromolar concentrations had adverse effects on cumulus expansion and viability, oocyte nuclear and cytoplasmic maturation and embryo development. At nanomolar concentrations, no adverse effects were found on COC viability and integrity whereas blastocyst had higher nuclear apoptosis. In donkey feed, toxin concentration was up to 2.7 ng/g with an incidence of 32%, far below the guidance values of OTA in feed materials reported by EU Recommendation 2016/1319. In jennies, the incidence of positive blood samples was 73% (median value= 114 ng/L; range 51 to 6000 ng/L). In foals, the incidence of positive blood samples was 50% (median value= 136 ng/L; range 79 to 4030 ng/L). No placental transfer of OTA was observed in all tested jennies and no influence on 2 pregnancy length and health of foals was observed. In milk, the incidence of positive samples was 36% (range 17 to 82 ng/L). In conclusion, in sheep, in vitro exposure to OTA affected oocyte function and embryo development; in jennies, no placental passage was observed but OTA passed from feed to milk through the blood. Effects on female fertility and newborn health need to be further investigated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
