RESUMO
In the original publication [...].
RESUMO
Mycotoxins and endocrine disruptors such as phytoestrogens can affect cattle health, reproduction, and productivity. Most studies of mycotoxins in dairy feeds in Mexico and worldwide have been focused on a few (regulated) mycotoxins. In contrast, less known fungal toxins, phytoestrogens, and other metabolites have been neglected and underestimated. This study analyzed a broad spectrum (>800) of mycotoxins, phytoestrogens, and fungal, plant, and unspecific secondary metabolites in whole-plant corn silages (WPCSs) and total mixed rations (TMRs) collected from 19 Mexican dairy farms. A validated multi-metabolite liquid chromatography/electrospray ionization-tandem mass spectrometric (LC/ESI-MS/MS) method was used. Our results revealed 125 of >800 tested (potentially toxic) secondary metabolites. WPCSs/TMRs in Mexico presented ubiquitous contamination with mycotoxins, phytoestrogens, and other metabolites. The average number of mycotoxins per TMR was 24, ranging from 9 to 31. Fusarium-derived secondary metabolites showed the highest frequencies, concentrations, and diversity among the detected fungal compounds. The most frequently detected mycotoxins in TMRs were zearalenone (ZEN) (100%), fumonisin B1 (FB1) (84%), and deoxynivalenol (84%). Aflatoxin B1 (AFB1) and ochratoxin A (OTA), previously reported in Mexico, were not detected. All TMR samples tested positive for phytoestrogens. Among the investigated dietary ingredients, corn stover, sorghum silage, and concentrate proportions were the most correlated with levels of total mycotoxins, fumonisins (Fs), and ergot alkaloids, respectively.
Assuntos
Micotoxinas , Bovinos , Animais , Micotoxinas/análise , Zea mays/química , Silagem/análise , Fitoestrógenos/análise , Fazendas , Espectrometria de Massas em Tandem/métodos , México , Contaminação de Alimentos/análiseRESUMO
This work was carried out to test whether viability of pig spermatozoa subjected to an osmotic test is correlated to sperm cryosurvival. Spermatozoa were cooled from 22 degrees C to -5 degrees C, aliquots were exposed to a series of hyperosmotic solutions (300-2100 mOsm/kg) for 15 min, immediately spermatozoa were re-warmed to 37 degrees C and isosmolarity was restored. Spermatozoa were cooled from 22 degrees C to -5 degrees C and one aliquot was exposed to the osmotic test while diluted spermatozoa were frozen-thawed. Plasma membrane-intact spermatozoa decreased as osmolarity increased (P < 0.0001), a further decreased (P < 0.0001) was observed when isotonicity was restored. Proportions of plasma membrane-intact and acrosome-intact cells from the osmotic test were no different from those after freeze-thawing: 36% vs. 35%, 80% vs. 80%, respectively. A significant correlation was found between the proportion of acrosome-intact cells after freeze-thawing and that from the osmotic test (r = 0.81, P <0.01). This test provides a useful and economical mean to predict in vitro boar sperm cryosurvival.