Alessandro Malfatti

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.

Plasma melatonin in domestic female Mediterranean sheep (Comisana breed) and goats (Maltese and Red Syrian)

The plasma melatonin nychtemeral profiles in Mediterranean ewes and goats were evaluated six times throughout the year. Melatonin levels were high throughout the night and generally below the assay detection limit during daytime. However, during long days, 30% of the last daytime samples had high melatonin concentrations. Plasma melatonin levels were higher in Comisana sheep than in goats, and higher in Maltese than in Red Syrian goats, with highly significant effect of the individual animal and high repeatability. Plasma melatonin was higher in April than in August. When there was a large difference between the duration of day and night, the plasma melatonin pattern and the light/dark cycle did not always match exactly, suggesting some form of superimposition and/or the prevalence of an endogenous rhythm. The difference found at similar scotoperiods with increasing or decreasing day length may be involved in the perception of the photoperiodic changes.

Measurement of thyroid hormones in donkey (Equus asinus) blood and milk: validation of ELISA kits and evaluation of sample collection, handling and storage

Donkeys milk is well tolerated by human infants with cows milk allergy and is useful in the treatment of human immune-related diseases and in the prevention of atherosclerosis. Thyroid hormones (TH) stimulate lactation and active triiodothyronine (T3) in colostrum and milk could take paracrine action supporting lactogenesis in the mother, and play physiological roles for the suckling offspring (systemic or within the gastrointestinal tract). The aims were to measure TH concentrations in donkey blood and milk, validate ELISA methods, evaluate the effects of sample collection and post-collection handling and the stability of TH in milk and blood serum and plasma samples. In milk and blood samples obtained from lactating jennies total concentrations of TH were assayed using competitive-type ELISA kits. Good validation results were obtained for both TH concentrations in blood serum and plasma and T3 in milk samples extracted with cold (-20°C) ethanol alkalinized (pH 9·0) with NH4OH. In most of the milk extract samples, thyroxine (T4) concentrations resulted below the sensitivity threshold. Intra- and inter-assay coefficients of variations of TH concentrations in different blood and milk samples were below 10%. Parallelism tests gave displacement lines parallel to those of the calibrators for both TH in blood serum and plasma and for T3 in milk extracts. Mean recovery rates were between 95% and 123%, but the concentration values approaching the highest calibrators were overestimated. Therefore, serum and plasma samples for T3 assay must be previously diluted with buffer. Both TH concentrations in blood serum and plasma and T3 in milk did not change during storage for up to 6 months at -20°C. In conclusion, the ELISA methods tested in the present study are suitable for determination of both TH concentrations in donkey blood samples, and for T3 measurement in milk, after extraction with cold alkaline ethanol.

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.

Thyroid Hormones in Donkey Blood and Milk: Correlations with Milk Yield and Environmental Temperatures

Thyroid hormones (TH) are the primary endocrine stimulators of non-shivering thermogenesis and are known to stimulate lactation. Triiodothyronine (T3) is the bioactive form, mainly derived by deiodination of thyroxine (T4), and the free quote (unbound to plasma proteins) is immediately bioavailable. This study aimed to evaluate potential relationships among TH in the blood, triiodothyronine in the milk (T3M), milk yield and environmental temperature in March to July for 8 lactating donkeys. Milk yield and blood TH concentrations changed significantly over time, whereas T3M was rather stable among individuals and not affected by time of sampling. Free T3 was not correlated with free T4 or with total TH in the blood, but it was weakly correlated with T3M. No relationship was found between blood TH and milk yield, which was negatively correlated with T3M. Thus, the absolute quantity of bioactive hormone in milk secretion is maintained. Milk yield was positively correlated with the free/total T3 and free T3/free T4 ratios, thus in turn with the relative quote of the circulating bioactive hormone. Circulating T3/T4 ratios were negatively correlated with environmental temperature. It is concluded that environmental temperature, in the range of the present study (-2 to 35°C), does not significantly entrain thyroid gland activity, which is affected more by other factors, such as inter-individual variations and physiological status (i.e., stage of lactation). However, increases in environmental temperature most likely induce decreases in deiodinase activity at the peripheral tissue level, as indicated by the decrease in the T3/T4 ratios in the blood.

Validation of ELISA kits for determination of Inhibin-A and Estradiol-17-beta concentrations in Buffalo plasma

Abstract The aim was to evaluate the suitability of two commercial ELISA kits for human serum or plasma, to measure Inhibin-A (In-A) and Estradiol-17-beta (E2) concentrations in buffalo plasma. Blood samples were obtained by jugular venipuncture from buffalo heifers and cows, and plasma samples were stored at – 20°C until assays. Precision of the methods was evaluated by the intra- and inter-assay coefficients of variation (CVs) of buffalo plasma sample replicates, at different concentrations. Accuracy was evaluated calculating the recovery rates of different proportions of the highest standard added to a buffalo plasma sample at low concentration (observed/expected values x 100). Linearity was evaluated by serially diluting one buffalo plasma sample at high concentration with the assay buffer and calculating by regression analysis the parallelism of the resulting line with the standard line. Intra-assay CVs were 11% and 15.1% for In-A and 1.8% and 3.3% for E2. Inter-assay CVs were 13.9% and 7.4% for In-A and E2, respectively. Mean recovery rate was 97.9% and 98.5% for In-A and E2, respectively. Dilution tests gave good parallelism between the lines obtained and the standard lines. It is concluded that the kits tested are suitable and reliable for buffalo plasma samples.

LH peak and ovulation in buffalo cows treated for oestrus synchronisation using two different hormonal schedule

Riassunto Picco di LH ed ovulazione in bufale trattate per la sincronizzazione dell’estro con due diversi protocolli ormonali. Scopo del lavoro è stato quello di valutare il picco di LH e l’ovulazione in bufale sottoposte a due diversi protocolli ormonali di sincronizzazione dei calori al fine della applicazione della inseminazione artificiale (IA). Gli animali sono stati assegnati a due gruppi: gruppo A (n=12), trattato con una spirale intravaginale contenente progesterone (PRID), associata alla somministrazione di PMSG e di un analogo della PGF2α; gruppo B (n=12) trattato con GnRH + PGF2µ + GnRH (Ovsynch). La determinazione dell’LH è stata fatta mediante ELISA. Il picco di LH e l’ovulazione sono avvenuti rispettivamente a 51,30±13,94 e a 85,14±13,63 ore dalla fine del trattamento, mentre l’intervallo medio tra picco LH e ovulazione è stato di 33,71±4,30 ore. Non si sono registrate differenze significative né tra i gruppi né tra i mesi in cui è stato effettuato il trattamento. Una migliore efficienza nella sincronizzazione del picco di LH e dell’ovulazione è stato ottenuto col trattamento Ovsych (gruppo B).

Isolation of pregnancy-associated glycoproteins (PAG) from water buffalo (Bubalus bubalis) placenta by use of Vicia villosa bound agarose affinity chromatography

Abstract The present study describes the isolation and characterisation of new PAG molecules extracted from mid- and late-pregnancy placentas in the water buffalo (Bubalisbubalis). After extraction, acid and ammonium sulphate precipitation and DEAE chromatography water buffalo PAG (wbPAG) were enriched by Vicia villosa agarose (VVA) affininity chromatography. As determined by Western blotting with anti-PAG-sera, apparent molecular masses of immunoreactive bands from VVA peaks ranged from 59.5 to 75.8 kDa and from 57.8 to 80.9 kDa in the mid- and late- pregnancy placenta respectively. Aminoterminal microsequencing of proteins allowed the identification of three distinct wbPAG sequences wich have ben deposed in the SwissProt database: RGSXLTIHPLRNIRDFFYUG (Acc. n. P85048), RGSXLTILPLRNIID (P85049) and RGSXLTHLPLRNI (P85050). Their comparison to those previously identified revealed that two of them were new since they have not been described yet. Our results confirm the suitability of VVA chromatography in enrichment of multiple PAG molecules expressed in buffalo placenta. Productions of specific antisera can be very useful in immonoistochemical and immunocyitochemical studies of PAG expression in fetomaternal interfaces. Purified native PAG are also required for development on specific immoassays (RIA/ELISA) currently used for pregnancy diagnosis and physiological investigation in farm animal.

Follicular development, plasma Inhibin-A and Estradiol-17-beta concentrations in Buffalo cows during different treatment schedules for MOET programs

Abstract Buffalo cows were submitted to three superovulatory treatments. T1 (n = 7): PRID for 10 days (d0-d9) plus decreasing doses of 500 IU FSH/LH (12 h-intervals d7-d10); T2 (n = 8): PRID for 11 d (d0-d10) plus 2000 IU PMSG at d7; T3 (n = 9): PRID for 11 d plus 2000 IU PMSG at d7 and decreasing doses of 175 IU FSH/LH (12 h-intervals d10- d11). Overall plasma inhibin-A (In-A) concentrations correlated with large follicles (LF, diameter >6mm, R=0.83, P<0.01) and small follicles (SF, <6mm, R=-0.21, P<0.01). Plasma E2 correlated weakly with LF (R=0.21, P<0.05). Within treatment, there was always a positive correlation between In-A and LF (T1 R=0.83; T2 R=0.81; T3 R=0.83; P<0.01), but only in T3 there were correlations between In-A and E2 (R=0.67, P<0.01) and SF (R=-0.42, P<0.01), between E2 and LF (R=0.39, P<0.01) and SF (R=-0.35, P<0.05). T3 was followed by a higher number of follicles with diameter >10 mm at d12-13 (T1=5.0+/-1.4, T2=1.2+/-0.9, T3=8.3+/-2.3). In-A concentrations significantly rised at d11-13 of T1 and T3. In-A seems a good indicator of the follicular development during superovulation in buffalo cows, while E2 is not. Furthermore T3 was followed by better ovarian follicular responses.