Flow cytometry is a useful tool that provides an accurate, objective and rapid evaluation of semen quality. The use of this technique could significantly improve the quality of buffalo semen samples used in artificial insemination. This study was carried out to evaluate, by flow cytometry, frozen-thawed buffalo spermatozoa quality parameters such as sperm viability by SYBR-14/propidium iodide staining; mitochondrial function by JC-1 potentiometric probe; sperm chromatin stability (SCSA) by acridine orange; and acrosome reaction (AR) by FITC-PNA staining. Semen samples from five Italian Mediterranean buffalo bulls were used. Sperm viability was not different between bulls and ranged from 33.4% to 43.6%. A consistent rate (55.1 ± 10.8%) of sperm cells showed high mitochondrial membrane potential (Δψ(high)), with no significant differences between subjects. Sperm chromatin structure assay differed significantly between the five buffalo bulls; moreover, data showed high stability within each buffalo. DNA fragmentation indexes (DFI), such as %-DFI, -DFI, SD-DFI, were 11.2 ± 8.6, 153.3 ± 24.6 and 81.6 ± 21.2, respectively. Regarding AR, the percentage of acrosome-reacted live (ARL) and acrosome-reacted dead (ARD) spermatozoa was 0.3 ± 0.2 and 15.3 ± 5.5, respectively. This functional parameter differed significantly between buffalo bulls and showed high stability. Following to Ca(2+) ionophore A23187 for 3 h, AR significantly differed between subjects and was characterized by an increase in both ARL (10.8%) and ARD population (22.0%). This study indicates that flow cytometry could be a useful tool for a quick multiparametric evaluation of sperm quality in buffalo. In particular, SCSA and AR resulted in sperm functional parameters sensitive enough for the diagnosis of frozen-thawed semen fertilizing potential.

Knowledge on genetic diversity and structure of camel populations is fundamental for sustainable herd management and breeding program implementation in this species. Here we characterized a total of 331 camels from Northern Africa, representative of six populations and thirteen Algerian and Egyptian geographic regions, using 20 STR markers. The nineteen polymorphic loci displayed an average of 9.79 ± 5.31 alleles, ranging from 2 (CVRL8) to 24 (CVRL1D). Average He was 0.647 ± 0.173. Eleven loci deviated significantly from Hardy-Weinberg proportions (P<0.05), due to excess of homozygous genotypes in all cases except one (CMS18). Distribution of genetic diversity along a weak geographic gradient as suggested by network analysis was not supported by either unsupervised and supervised Bayesian clustering. Traditional extensive/nomadic herding practices, together with the historical use as a long-range beast of burden and its peculiar evolutionary history, with domestication likely occurring from a bottlenecked and geographically confined wild progenitor, may explain the observed genetic patterns.

Juvenile in vitro embryo transfer (JIVET) reduces the generation interval and increases the rate of genetic gain. The developmental competence of in vitro-produced embryos is strictly related to oocyte quality. Oxidative stress in the oocyte is an emerging problem in reproductive in vitro technologies, due to the gas atmosphere used to incubate oocytes and the lack of physiological defense mechanisms available in the female reproductive tract. The major source of reactive oxygen species (ROS) is represented by mitochondria where ROS are produced during oxidative phosphorylation. The aim of the present study was to analyze mitochondria and ROS in ovine prepubertal oocytes before and after IVM in order to clarify their suitability in JIVET programs. Cumulus-oocyte complexes from the ovaries of 38 slaughtered prepubertal (less than 8 months of age) lambs of the Comisana breed were analyzed at retrieval (group A) or after IVM (group B; Ambruosi et al. 2009 Theriogenology 71, 1093-1104). After cumulus cell removal, all oocytes underwent nuclear chromatin, mitochondria and ROS evaluation by confocal analysis of fluorescence distribution and intensity. Hoechst 33258 and Mitotracker Orange CMTM Ros (Molecular Probes Inc., Eugene, OR) were used to label nuclear chromatin and mitochondria (Ambruosi et al. 2009) and 2′,7′-dichloro-dihydro-fluorescein diacetate was used for ROS labelling (Hashimoto et al. 2000 Mol. Reprod. Dev. 57, 353-360). Out of 65 oocytes from group A, 38 oocytes with regular size (>130 μm in diameter), morphology and nuclear chromatin at the GV stage were selected for analysis. One-hundred-thirty-eight oocytes underwent IVM (group B). Nuclear maturation rate (metaphase II with 1st polar body extruded) was 54%, 75/138. All MII oocytes were used for analysis. Significantly higher rate of oocytes from group B showed heterogeneous (large aggregates, clusters, pericortical, perinuclear) mitochondrial (mt) distribution pattern than oocytes from group A (55%, 41/75 v. 29%, 11/38, respectively; P < 0.05) which showed uniform distribution of small mt aggregates. Fluorescent intensity of mt labeling did not differ between groups (43.05 ± 16.15 v. 45.89 ± 10.36, for group A and B respectively; NS). In most of the oocytes from both groups, intracellular ROS were distributed in small or large aggregates (35/38, 92% and 62/75, 83%). No statistical difference was observed for intracellular ROS levels between oocytes from group A (66.36 ± 13.2) and group B (72.84 ± 20.63; NS). The culture conditions used in this study provided normal mt distribution and intracellular ROS levels. Qualitative and quantitative evaluation of mitochondria and intracellular ROS could be useful to improve in vitro culture methods in ovine prepubertal oocytes.

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