Assessment of different functional parameters of frozen-thawed buffalo spermatozoa by using cytofluorimetric determinations.

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.

Gene expression of pregnancy-associated glycoproteins-1 (PAG-1), interferon-tau (IFNt) and interferon stimulated genes (ISGs) as diagnostic and prognostic markers of maternal-fetal cellular interaction in buffalo cows.

The aim of this study was to determine the presence of Pregnancy-associated glycoprotein -1 (PAG-1) mRNA expression in the maternal circulation of pregnant buffaloes during the early stage of pregnancy. Contemporaneously, the mRNA expression levels of Interferon-tau (IFNt) and some Interferon stimulated genes (ISGs) (interferon stimulated gene 15 ubiquitin-like modifier interferon, ISG15; Mixoviruses resistance 1 and 2, MX1 and MX2; 2',5'-oligoadenylate synthase 1,OAS1) were evaluated in order to expand our knowledge of the molecular processes involved in the early stages of pregnancy and to identify potential biomarkers of maternal-fetal cellular interaction in buffalo. The study was conducted on 38 synchronized and artificially inseminated buffalo cows (d 0), divided ex post into 3 groups: Pregnant (n = 17), Non-pregnant (n = 15) and Embryo mortality (n = 6). Blood samples were collected on d 14, 19, 28 and 40 after artificial insemination (AI) for peripheral blood mononuclear cells (PBMCs) isolation. Expression levels of mRNA of PAG-1, IFNt, ISG15. MX1, MX2 and OAS1 were measured using RT-qPCR. No significant changes were observed in IFNt and PAG gene expressions between groups, while significant differences (p < 0.001) were found for ISG15, MX1, MX2, and OAS1. Pairwise comparisons revealed that the differences between groups occurred on days 19 and 28 post-AI. ISG15 proved to have the best diagnostic performance for distinguishing between pregnant animals and animals that experienced embryo mortality with the ROC analysis. According to the results of the univariate analyses, day 19 was identified as the most indicative to discriminate between groups while the most reliable genes for this differentiation were ISG15, MX1 and MX2. MX2 proved to be the best gene for discriminating pregnant buffaloes using the discriminant analysis, while MX1 was the gene that best predicted embryo mortality. Our results showed that among PAG-1, IFNt and ISGs expression as diagnostic and prognostic markers of maternal-fetal cellular interaction in buffalo cows, ISGs proved to be the best peripheral biomarkers for predicting pregnancy and embryonic mortality during the peri-implantation period. These insights into the mechanisms behind maternal-fetal interaction and the development of a method for the early detection of embryo distress may enable us to implement effective strategies to support embryo survival.

Isolation of new pregnancy-associated glycoproteins from water buffalo (Bubalus bubalis) placenta by Vicia villosa affinity chromatography.

The present study describes the isolation and characterization of new pregnancy-associated glycoprotein molecules (PAG) from midpregnancy and late-pregnancy placentas in the water buffalo (Bubalus bubalis). After extraction, the homogenates are subjected to acid and ammonium sulfate precipitations followed by DEAE chromatography. Subsequently, the water buffalo PAG (wbPAG) from these solutions are enriched by Vicia villosa agarose (VVA) affinity chromatography. As determined by western blotting with anti-PAG sera, the apparent molecular masses of the immunoreactive bands from the VVA peaks range from 59.5 to 75.8kDa and from 57.8 to 73.3kDa in the midpregnancy and late-pregnancy placentas, respectively. Amino-terminal microsequencing of the immunoreactive proteins has allowed the identification of three distinct wbPAG sequences, which have been deposited in the SwissProt database: RGSXLTIHPLRNIRDFFYVG (acc. no. P85048), RGSXLTILPLRNIID (acc. no. P85049), and RGSXLTHLPLRNI (acc. no. P85050). Their comparison to previously identified proteins has shown that two of them are new because they have not been described before. Our results confirm the suitability of VVA chromatography for the enrichment of the multiple PAG molecules expressed in buffalo placenta.

Using real-time PCR to identify pregnancy-associated glycoprotein 2 (PAG-2) in water buffalo (Bubalus bubalis) blood in early pregnancy.

This study investigates for the first time mRNA pregnancy-associated glycoprotein 2 (PAG-2) expression in blood cells during early pregnancy in water buffalo. The PAGs constitute a large family of glycoproteins expressed in the outer epithelial layer of the placenta in eutherian species. All PAGs are not concomitantly expressed throughout pregnancy; some of them are expressed in the earlier phases, whereas others appear later and are expressed over a shorter period. Twenty-one lactating buffaloes were analyzed-17 females were synchronized with PRID and artificially inseminated (AI), whereas four females were synchronized but not inseminated (control group). Blood was collected at Days 0, 18, 28, 40, and 75 from AI (AI = Day 0). Expression of PAG-2 mRNA in blood samples was measured with real-time polymerase chain reaction. Pregnancy diagnosis was performed on Day 28 (D28) and Day 40 (D40) after AI by ultrasonography (US) and by PAG-1 RIA method. The females diagnosed pregnant at D28 and confirmed pregnant at D40 were defined as D28(+)D40(+) group; the females diagnosed pregnant at D28 but not confirmed pregnant at D40 were defined as D28(+)D40(-) group; and the females that were diagnosed as nonpregnant on either days were defined as D28(-)D40(-) group. PAG-2 mRNA at Day 0 was not observed in any groups. The D28(+)D40(+) group showed the highest expression, starting on Day 18 and increasing progressively up to Day 75. PAG-2 mRNA was also expressed on Day 18 in both D28(+)D40(-) and D28(-)D40(-) groups, but their levels were lower than those of D28(+)D40(+) group and almost constant over time. PAG-2 mRNA was never detected in the control group. The significant difference in the expression of PAG-2 mRNA between the D28(+)D40(+) group and the D28(-)D40(-) group, starting from Day 18, suggests that these animals might have conceived, but have experienced early embryonic loss; therefore, the PAG-2 mRNA was still present in blood circulation although at lower levels, as found in the D28(+)D40(-) group. In conclusion, this study shows that PAG-2 mRNA can be detected in peripheral maternal blood cells earlier than circulating PAG-1 molecules and could be useful for studies on early pregnancy and embryonic mortality.

Pregnancy-associated glycoproteins (PAGs) concentrations in water buffaloes (Bubalus bubalis) during gestation and the postpartum period.

For the first time in literature this study describes the pregnancy-associated glycoprotein (PAG) profile of buffalo cows during gestation and the post-partum period using antiserum raised against PAG-molecules purified from buffalo placenta (AS#860). Ninety-eight buffalo cows, belonging to a buffalo herd subjected to a synchronization and artificial insemination (AI) program, were enrolled in this study. Blood samples were taken on days 0 (AI), 23, 25, 28, 30 and then biweekly until the end of pregnancy. Pregnancy was confirmed by ultrasonography on days 28 and 45, and by rectal palpation from day 60 onwards. Blood samples were suspended for the non-pregnant cows on day 45, while the blood of 20 buffaloes that had calved was tested every five days from the day of calving until day 50 post-calving. A cut-off value of 1.0 ng/mL was used in order to discriminate between pregnant and non-pregnant buffaloes. We used Linear Mixed models after Log(x+1) transformation to analyse the PAG concentrations. Fifty-two buffalo cows had become pregnant out of 98 synchronized (53%) and 46 remained non-pregnant (47%) as shown by ultrasonography and the PAG analysis. Significant differences (P < 0.001) in PAG concentrations were observed between the pregnant and non-pregnant buffaloes from day 23 as the PAG of the non-pregnant cows was always close to zero. Conversely, the PAG of the pregnant cows increased progressively from day AI until day 105 post-insemination and then stabilized until the end of pregnancy. Regarding pregnancy diagnosis, the sensitivity of PAG-RIA 860 system (ability of the test to correctly identify pregnant buffalo) ranged from 23% on day 23-98% on day 28 post AI; the specificity (ability to correctly identify non-pregnant buffaloes) was 100% throughout the sampling period. PAG progressively decreased from parturition to day 25 post-partum; from day 30 post-partum, the concentrations fell below 1 ng/mL and were close to 0 on the last day of observation (50 d post-partum). In conclusion, our results showed that RIA-860 is highly accurate for diagnosing pregnancy in buffaloes starting from day 28 of gestation. Furthermore, the rapid disappearance of PAG concentration after calving means that a cut-off limit in post-partum for detecting a new pregnancy is not required.

LH peak and ovulation after two different estrus synchronization treatments in buffalo cows in the daylight-lengthening period.

The aim of this study was to determine the timing of ovulation in relation to the LH peak after synchronization using PRID or Ovsynch protocols, to assess the effects of the period of treatment on these parameters and to provide information concerning how to use the two main protocols for fixed-time artificial insemination in buffalo. Forty-eight lactating Italian Mediterranean buffalo cows were used. The buffaloes were treated in various periods as follows: February to March (n = 12 PRID, n = 12 Ovsynch), end of the breeding season, May to June (n = 12 PRID, n = 12 Ovsynch), beginning of low-breeding season according to Italian environmental conditions. To determine the LH, blood samples were taken at 4-hour intervals, starting 24 hours from PRID removal (PRID group) or 12 hours from (PGF2α) injection (Ovsynch group) up to 108 hours. The ovaries were monitored by transrectal ultrasonography to verify ovulation. The LH-ovulation interval was similar in both groups (30.10 ± 1.05 and 32.77 ± 1.15 hours, respectively, in PRID and Ovsynch group). In the PRID group, the timing of ovulation in relation to device removal was 76.83 ± 3.65 hours with a high level of variability among the animals. In the Ovsynch group, we observed a better synchronization of LH peaks and ovulations, and the timing of ovulation in relation to the last GnRH injection was 35.67 ± 1.15 hours. The percentage of animals reaching the LH peak and ovulation was lower (P ≤ 0.05) in May to June (respectively 75.0% and 54.1%) compared to February to March (respectively 95.8% and 83.3%), indicating a reduction of hypothalamus-pituitary responsiveness to the synchronization treatments in the daylight-lengthening period.

Efficiency to reach age of puberty and behaviour of buffalo heifers (Bubalus bubalis) kept on pasture or in confinement.

In order to evaluate the influence of rearing system (free-ranging (FR) v. confinement (C)) on buffalo heifer efficiency to reach age of puberty and on behavioural and immune functions, two experiments were conducted from September 2010 to October 2011. In Experiment I, 32 subjects aged 8 to 9 months at the start of experiment were used. A total of 16 animals (group C) were group housed in an indoor slatted floor pen (4 m2/animal) with an outdoor paddock (4 m2/animal); 16 others grazed on a Mediterranean natural pasture of 40 ha (group FR). Behavioural data were collected and organic matter digestibility, blood metabolites and progesterone were determined. At the end of the experiment, a novel object test and a skin test were conducted, and the avoidance distance (AD) at the manger was measured. Free-ranging animals were able to express natural behaviours such as wallowing and grazing. C animals devoted more time to the novel object than FR animals, whereas AD at manger was lower in group FR than in group C (P<0.01). Cellular immune response was higher in FR heifers than in C animals (P<0.01). FR animals also showed a higher digestibility of organic matter (P<0.01). Heifers from group FR had higher plasma concentrations of non-esterified fatty acids (P<0.001) and lower concentrations of glucose than heifers from group C (P<0.001). C animals showed higher daily weight gains (P<0.01) and weight at the puberty (P<0.05), but there were no differences in terms of age of puberty between the two groups. The intakes of dry matter (DM), CP and energy to reach the age of puberty were similar in both groups. In order to verify whether the results obtained in Experiment I could be replicated in different rearing conditions (reduced pasture availability, different location and altitude), a second experiment was conducted on 26 animals, where only onset of age of puberty and metabolic profile were monitored. In Experiment II, 13 heifers grazed on a natural pasture of 5 ha, other 13 received the same space as indicated for Experiment I. Results from Experiment II generally confirmed those of Experiment I. Only the intakes of DM and energy to reach the age of puberty were higher in group C than in FR (P<0.001). A lower competition with human nutrition, reproductive performances similar to those shown by confined animals and the indications given by immune and behavioural variables, suggest that a free-range-based system may be conveniently used for buffalo heifer farming purposes.

In vitro maturation and fertilization of follicular oocytes in cattle.

This work aims towards developing research concerning the improvement of animal reproduction, embryo development and genetic engineering. In our laboratory, an attempt has been made to standardize in vitro conditions able to optimally support bovine oocyte maturation and fertilization in order to yield viable embryos. Ovaries from cows and heifers, obtained from local slaughter-house, were used for recovery of oocytes from antral follicles. Cumulus-oocyte complexes were statically cultured for 24h at 39 degrees C in medium TCM 199 supplemented with fetal calf serum inactivated, hormones, glucose and granulosa cells under a 5% CO2 and 95% humidity atmosphere. A first group of oocytes was used for fixing and staining procedure for evidence of in vitro maturation. After culture 69.4% (77/111) of oocytes reached full maturation showing cumulus expansion, first polar body extrusion and the 2nd metaphase plate. A 2nd group was used for in vitro fertilization. In vitro semen capacitation was obtained with swim-up system (8.9) with separation of high motility fraction in Talp Hepes medium. Oocytes and spermatozoa were coincubated for 18-20h in Talp medium at 39 degrees C with 5% CO2 and 95% humidity. At the end of culture stereoscope and microscope observations were made for evidence of fertilization. After IVF 67.4% (58/86) resulted fertilized. Most of them showed two pronuclei and residual sperm tail. In few cases oocytes with 1 pronucleus and the swollen sperm head or with syngamy or polyspermic were found. In these experiments high percentages of in vitro matured and in vitro fertilized oocytes have been obtained. These bovine zygotes can be considered an essential step to develop new technologies in cattle breeding.