Progesterone and equine chorionic gonadotropin concentrations around the time of pregnancy loss in mares impregnated by donkeys or stallions

The objective of this study was to compare the incidence of pregnancy loss of mares carrying a mule embryo with that of mares carrying a horse embryo. The possible causes of such mortality were evaluated through serial ultrasonographic evaluations and hormonal monitoring, paying special attention to the role of premature regression of the endometrial cups and its relation to inadequate luteal function.

Twenty-eight mares impregnated by stallions and 19 mares impregnated with donkey semen were evaluated ultrasonographically every week from day 20 to day 150 of pregnancy. The viability of the product was assessed each time, and the diameter of the embryonic vesicle was measured from day 25 to day 60. Blood samples for progesterone and equine chorionic gonadotropin (eCG) determination were taken every week.

Both progesterone and eCG concentrations during normal pregnancies wegre significantly lower in the mares inseminated with donkey semen than in the mares impregnated by stallions (P<.05). In 7 of the mares carrying mule conceptuses to term, the concentrations of eCG remained basal throughout the study. In the other animals from this group, the levels of this hormone did increase but returned to baseline much earlier (on day 77 of pregnancy) than in the mares served by stallions (on day 126 day of pregnancy). There was no significant difference between the growth rate of embryonic vesicles of mares carrying mule embryos and that of mares carrying horse embryos (P>.05).

The incidence of pregnancy loss was significantly higher (P<.05) in mares carrying a mule embryo (36.8 %) than in mares carrying a horse embryo (21.4%); it occurred on average on day 93 of pregnancy in mares carrying mule embryos and on day 43 on mares carrying horse embryos. There was only 1 case in which pregnancy loss was associated with concentrations of both eCG and progesterone that were much lower than the average for the normal pregnancies of the same group, and this was in a mare carrying a horse embryo. The most frequent cause of pregnancy loss was premature luteal regression due to primary luteolysis, as evaluated via peripheral progesterone concentrations. This occurred in 2 mares carrying horse embryos and in 4 mares carrying mule embryos. Three mares carrying mule embryos and 1 carrying a horse embryo had abortions that were not preceded or accompanied by any alteration in progesterone or eCG levels and were thus classified as fetal deaths of non-endocrine origin.

It is concluded that the incidence of pregnancy loss is higher in mares carrying a mule embryo than in mares carrying a horse embryo. However, this is not due to the low progesterone concentrations associated with the premature regression of the endometrial cups that occurs in mares with interspecific pregnancy.     

Evaluation of dry ashing in conjunction with ion chromatographic determination of transition metal ions in pig feed samples

The contents of transition metal ions iron, copper, zinc, and manganese were simultaneously determined in pig feed using an ion chromatographic technique (IC) preceded by dry ashing. Employing ion exchange, the ions were separated on an IonPac CS5A column used in combination with a pyridine-2,6-dicarboxylic acid based eluent. The separation was followed by spectrophotometric detection after postcolumn reaction with 4-(2-pyridylazo)resorcinol. Dry ashing parameters were varied to assess their role in potential analyte loss. Quantitative recoveries (>95%) were obtained for all analytes with a dry ashing method that included a moderate temperature-time regime and ash leaching support in the form of sonication and heat treatment. The use of HCl as leaching acid and the presence of alkaline earths in the matrix solution did not interfere with the chromatographic separation.     

Contribution of dimethyl sulfide to the aroma of Syrah and Grenache Noir wines and estimation of its potential in grapes of these varieties

The contribution of dimethyl sulfide (DMS) to the aroma of Syrah and Grenache Noir wines from the Rhone Valley of France was investigated by sensory analysis, and its levels in these wines were measured. The potential DMS in the corresponding grapes and wines, susceptible to release during wine aging, was evaluated. Free DMS and potential DMS assessed by a heat-alkaline treatment were measured in grape juices and wines by SPME-GC-MS using methods previously reported and slightly modified. A relationship between potential DMS from grapes and the total DMS levels in wine was demonstrated. Furthermore, a linear regression between the ratio of free DMS levels to these total DMS levels in wine and time of storage was found. Free and potential DMS levels in grapes and wines depended on grape variety, vintage, and vine location. DMS imparted a noticeable and complex contribution to the aroma of the wines investigated, depending on the mode of sensory perception used, either before or after glass swirling. It significantly enhanced the fruity notes of the wines, and additional truffle and black olive notes.     

Molecular Characterization by AFLPs of Capsicum Germplasm from the Amazon Department in Colombia

Using AFLPs, 71 peppers (Capsicum) accessions from the species C. chinense Jacq., C. baccatum L., C. annuum L. and C. frutescens L. from indigenous communities of the Amazon Department (Colombia) were studied to assess the genetic diversity of the collections, and delineate species gene groups. Ten additional accessions were included as a reference species group. Three clusters were identified in the Amazonian accessions by Multiple Correspondence Analyses (MCA) and a dendrogram from the UPGMA analyses of Nei – Li genetic similarity. The clusters correspond to gene groups of the species Capsicum chinense (the majority of the accessions), C. baccatum and the complex annuum - frutescens. A fourth cluster corresponds to the reference accession C. pubescens. The MCA analyses accounted for 95% of the total variation. The total genetic variation was low (Ht 0.119) and a genetic diversity index (Gst) of 0.331 was obtained. This suggests a limited genetic diversity of the accessions and a close relatedness of the species. This study is the first molecular marker assessment of genetic diversity for peppers from the Colombian Amazon, and provides information of biodiversity that can be employed in the preservation and use of Capsicum germplasm.     

Olfactory perception of cysteine-S-conjugates from fruits and vegetables

Volatile sulfur compounds have a low odor threshold, and their presence at microgram per kilogram levels in fruits and vegetables influences odor quality. Sensory analysis demonstrates that naturally occurring, odorless cysteine- S-conjugates such as S-( R/ S)-3-(1-hexanol)- l-cysteine in wine, S-(1-propyl)- l-cysteine in onion, and S-(( R/ S)-2-heptyl)- l-cysteine in bell pepper are transformed into volatile thiols in the mouth by microflora. The time delay in smelling these volatile thiols was 20-30 s, and persistent perception of their odor occurred for 3 min. The cysteine- S-conjugates are transformed in free thiol by anaerobes. The mouth acts as a reactor, adding another dimension to odor perception, and saliva modulates flavors by trapping free thiols.