Effectiveness of near-infrared spectroscopy to predict the chemical composition of feces and total-tract apparent nutrients digestibility estimated with uNDF or AIA in lactating buffaloes' feces

Following a comparison of nutrient total-tract digestibility estimates in lactating buffaloes using single-point undigestible NDF (uNDF) or acid-insoluble ash (AIA) as internal markers, the potential of fecal near-infrared spectroscopy (NIRS) to provide calibration equations for the assessment of the chemical composition of feces and nutrient total-tract digestibility estimated with internal markers was explored. Chemical analyses were performed on 147 fecal samples from lactating buffaloes reared in 5 farms in central Italy (Naples). Each farm fed a silage-based total mixed ration (TMR) to the buffaloes, which was sampled in the 2 d before the fecal collection. The TMR and individual fecal samples were collected and analyzed for dry matter (DM), organic matter (OM), ash, AIA, ether extract (EE), starch, fiber fractions (aNDFom, aNDF, ADFom, ADF, hemicellulose, cellulose, ADL, uNDF), N, CP and CP bound to aNDF (NDICP) and to ADF (ADICP). The uNDF content was determined through a 240-h in vitro fermentation and employed, together with AIA as markers to estimate the total-tract apparent digestibility (ttaDe) and total-tract digestibility (ttDe) of DM, OM, ash, N, CP, EE, aNDFom, aNDF, NDIP, ADFom and ADF, ADIN, ADL, hemicellulose, cellulose, starch, non-fibrous carbohydrates (NFC) and fraction B3 of N. No correlation was found between DM and OM digestibility estimated with AIA and uNDF as internal markers. Weak correlations were detected for all the other nutients digestibilities while strong correlations were observed for EE, ADFom, HC, NDIN, ADIN, NB3, NFC and starch.Inizio modulo The sample set (n = 147) was divided in a calibration set (n = 111) and a validation set (n = 36) to "train" and "validate" the fecal NIRS curve through an external validation process. An estimation usable for preliminary or initial evaluation was obtained for N, CP and aNDF fecal content. An excellent prediction was obtained for ttADINDe (R2 = 0.90) when estimated with uNDF as internal marker. The NIRS technology was not able to accurately predict all the other traits and the estimated nutrient digestibility of lactating buffalo diets from fecal spectra.

Dietary supplementation with green tea extract improves the antioxidant status and oocyte developmental competence in Italian Mediterranean buffaloes

The aim of this work was to assess the antioxidant status and the developmental competence of oocytes recovered by ovum pick-up (OPU) in Italian Mediterranean buffaloes supplemented with green tea extracts (GTE) for 90 days. Buffalo cows (n = 16) were randomly assigned to a control group receiving no supplement and a treatment group, receiving GTE starting 90 days before OPU, carried out for five consecutive sessions. Blood samples were collected before the start of supplementation with GTE (T0) and at day 45 (T1) and day 90 (T2) of supplementation, to measure ferric reducing activity (FRAP), total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase (CAT). The antioxidant status of follicles was measured as TAC on the follicular fluid collected from the dominant follicle just prior OPU, coinciding with T2, and at the end of five repeated OPU sessions (T3). Another objective was to assess in vitro the protective effects of green tea extracts on hepatic cells exposed to methanol insult. Different concentrations of GTE (0.5 μM and 1 μM) were tested on cultured hepatic cells and viability, morphology and SOD activity were assessed at 24, 48 and 72 h. Supplementation with GTE increased (P < 0.05) the number of total follicles (8.7 ± 0.5 vs 6.9 ± 0.5), the number and the percentage of Grade A + B cumulus-oocyte complexes (COCs) compared with the control (3.7 ± 0.4 vs 2.3 ± 0.3 and 57.5 ± 4.2 vs 40.4 ± 4.9 %, respectively). Oocyte developmental competence was improved in the GTE group as indicated by the higher (P < 0.05) percentages of Grade 1,2 blastocysts (44.8 vs 29.1 %). In the GTE group, plasma TAC was higher both at T1 and T2, while FRAP increased only at T2, with no differences in SOD and CAT. The TAC of follicular fluid was higher (P < 0.05) in the GTE compared to the control both at T2 and at T3 The in vitro experiment showed that co-treatment with methanol and 1 μM GTE increased (p < 0.01) cell viability at 24 h (P < 0.01), 48 h (P < 0.05) and 72 h (P < 0.01) compared with the methanol treatment co-treatment with 1 μM GTE prevented the decrease in SOD activity observed with methanol at 24 and 48 h of culture. In conclusion, the results of in vivo and in vitro experiments suggest that supplementation with GTE increases buffalo oocyte developmental competence, by improving oxidative status and liver function.

Effect of crocin supplementation in the extender on the quality of chilled canine semen

The aim of the study was to evaluate the effects of crocin on canine sperm quality parameters during prolonged storage at 4 °C. Ejaculates from 10 dogs were diluted in a TRIS- egg yolk extender supplemented with 0 (control group), 0.5, 1, and 2 mM crocin and stored at 4 °C. Sperm membrane functional integrity, motility, and kinetics were assessed after 3 h, 24 h, 4 days and 7 days of storage. Based on the results, the more efficient concentration of crocin (0.5 mM) was chosen to evaluate sperm intracellular ROS levels, lipid peroxidation, and DNA fragmentation vs. the control. Semen with the addition of 0.5 mM crocin with respect to the control exhibited: i) increased (P < 0.05) sperm membrane functionality at 4 and 7 days of storage; ii) higher (P < 0.05) average path (VAP), straight-line velocities (VSL), and beat cross frequency (BCF) at 4 d of storage at 4 °C; iii) decreased (P < 0.05) intracellular ROS levels after 3 and 24 h storage. No differences in lipid peroxidation and DNA fragmentation were recorded between the control and C0.5 groups at any time point. Lipid peroxidation did not increase over time, while DNA fragmentation increased (P < 0.05) in both groups after 4 days of storage. The results demonstrated that the enrichment of extender with crocin improves to a certain extent canine semen quality, particularly after 4 days of storage at 4 °C.

Seasonal variations in the metabolomic profile of the ovarian follicle components in Italian Mediterranean Buffaloes

The aim of this work was to evaluate the seasonal effect on the metabolomic profile of the ovarian follicle in Italian Mediterranean buffalo to unravel the causes of the reduced competence during the non-breeding season (NBS). Samples of follicular fluid, follicular cells, cumulus cells and oocytes were collected from abattoir-derived ovaries during breeding season (BS) and NBS and analyzed by 1H Nuclear Magnetic Resonance. The Orthogonal Projections to Latent Structures of the Discriminant Analysis showed clear separation into seasonal classes and Variable Importance in Projection method identified differentially abundant metabolites between seasons. Seasonal differences were recorded in metabolite content in all analyzed components suggesting that the decreased oocyte competence during NBS may be linked to alteration of several metabolic pathways. The pathway enrichment analysis revealed that differences in the metabolites between the seasons were linked to glutathione, energy generating and amino acid metabolism and phospholipid biosynthesis. The current work allows the identification of potential positive competence markers in the follicular fluid as glutathione, glutamate, lactate and choline, and negative markers like leucine, isoleucine and β-hydroxybutyrate. These results form a major basis to develop potential strategies to optimize the follicular environment and the IVM medium to improve the competence of oocytes during the NBS.

Variations of follicular fluid extracellular vesicles miRNAs content in relation to development stage and season in buffalo

In buffalo (Bubalus bubalis) reproductive seasonality, causing cycles of milk production, is one of the major factors affecting farming profitability. Follicular fluid (FF) contains extracellular vesicles (EVs) playing an important role in modulating oocyte developmental competence and carrying microRNAs (miRNAs) essential for in vitro fertilization outcomes. The aim of this work was to characterize the FF-EVs-miRNA cargo of antral (An) and preovulatory (pO) follicles collected in the breeding (BS) and non-breeding (NBS) seasons, to unravel the molecular causes of the reduced oocyte competence recorded in buffalo during the NBS. In total, 1335 miRNAs (538 known Bos taurus miRNAs, 324 homologous to known miRNAs from other species and 473 new candidate miRNAs) were found. We identified 413 differentially expressed miRNAs (DE-miRNAs) (FDR < 0.05) between An and pO groups. A subset of the most significant DE-miRNAs between An and pO groups targets genes which function is related to the lipid and steroid metabolism, response to glucocorticoid and oestradiol stimulus. Comparison between BS and NBS showed 14 and 12 DE-miRNAs in An-FF-EVs and pO-FF-EVs, which regulate IL6 release and cellular adhesion, respectively. In conclusion, these results demonstrated that the miRNA cargo of buffalo FF-EVs varies in relation to both follicular development and season.

Effect of Aqueous Extract of Maca Addition to an Extender for Chilled Canine Semen

Simple Summary

The wide use of artificial insemination in dogs justifies the development of new strategies to prevent the reduction of fertilizing ability of stored semen. In recent years, the use of plant antioxidant supplementation has become increasingly popular. Maca (Lepidium meyenii) is an Andean edible root with antioxidant properties. The effectiveness of the oral supplementation of Maca in improving fresh semen quality and quantity and cooling or freezing ability has already been reported. This is the first in vitro study on the effects of aqueous extract of Maca on canine spermatozoa. The addition of low concentrations of aqueous extract of Maca to the canine chilled extender had positive effects only until 24 h of storage, increasing hyperactivation of sperm cells and preserving DNA integrity of spermatozoa in short-term storage. Meanwhile, a high concentration of Maca had an immediately deleterious effect on semen quality.

Abstract

Antioxidant supplementation has been proposed as a new strategy to improve the long-term preservation of semen. The aim of this study was to evaluate the effect of Maca supplementation of semen extender on quality-related canine semen parameters during cooling. Ejaculates from nine dogs were cooled for 7 days in the absence (control group) or in the presence of 10, 20 and 50 μL/mL of an aqueous extract of Maca. Sperm were evaluated for sperm viability, motility, DNA fragmentation and lipid peroxidation after 3 h, 24 h, 4 days and 7 days of storage. The addition of 10 μL/mL of Maca preserved sperm DNA and plasma membrane integrity at 3 h and increased sperm curvilinear velocity after 24 h. Treatment with 20 and 50 μL/mL of Maca increased the percentage of hyperactivated sperm after 3 h. Moreover, semen treated with 20 μL/mL of Maca decreased lipid peroxidation at 24 h. A significant reduction of sperm DNA and plasma membrane integrity as well as of kinetics parameters between 3 and 24 h of refrigerated storage with the higher concentration tested was observed. Although Maca was not able to protect canine semen with extended refrigeration storage time, it increased hyperactivation and preserved DNA integrity in short-term storage.

Effects of Dietary Supplementation of Conjugated Linoleic Acids and Their Inclusion in Semen Extenders on Bovine Sperm Quality

Simple Summary

Suboptimal fertility in males accounts for about two-thirds of infertility cases, thus being of serious concern for the dairy industry, where optimal fertility is fundamental for farm profitability. Although genetic defects responsible for subfertility have been identified, the role of seminal compounds on fertility remain unclear. Feeding rumen-protected isomers of conjugated linoleic acid (CLA) to dairy cows reportedly enhances circulating insulin-like growth factor I (IGF-I) levels. In breeding bulls, the IGF-I concentration in seminal plasma has been positively correlated with fertility rates. Therefore, the objective of the study was to evaluate the effect of dietary CLA supplementation and of their inclusion to the semen extender on bovine semen quality and freezability.

Abstract

Isomers of conjugated linoleic acid (CLA) enhances circulating insulin-like growth factor I (IGF-I) levels. Furthermore, fertility rate of breeding bulls is positively correlated to seminal plasma IGF-I concentration. Our objective was to evaluate the effect of dietary CLA supplementation and inclusion to the semen extender on bovine semen quality and freezability. Fourteen bulls, randomly assigned to control (CTL) and CLA (50 g/day) groups, were supplemented for 10 weeks. Samples were collected at Weeks −2 (before supplementation), 0, 4, 6 (during supplementation), 10, and 11 (after supplementation). Blood and seminal plasma were analyzed for IGF-I; the ejaculates were frozen in the following subgroups: CTL (no addition to semen extender), CLA c9, t11 (50 µM), CLA c9, t11 (100 µM), CLA t10, c12 (50 µM), CLA t10, c12 (100 µM), and CLA mix (50 µM each of CLA c9, t11 and CLA t10, c12). Sperm motility, morphology, viability, mitochondrial membrane potential, and reactive oxidative species were assessed. CLA supplementation decreased ejaculates’ total volume, increased sperm concentration, beat cross frequency, and decreased oxidative stress; it also increased plasma and seminal plasma IGF-I levels compared to the CTL. The inclusion of CLA c9, t11 100 µM and CLA mixture in the extender increased live spermatozoa percentage post-thawing compared to other groups. Our results show a beneficial effect of CLA supplementation on semen quality; however, further studies evaluating fertilization rates are necessary to corroborate the results.

Severe bone microarchitecture deterioration in a family with hereditary neuropathy: evidence of the key role of the mechanostat

In this report, we present three cases of individuals from the same family with a diagnosis of CMT with severe tibia bone microarchitecture deterioration assessed by HR-pQCT. Charcot-Marie-Tooth disease (CMT) or hereditary neuropathy involves both motor and sensory nerves. Falls are often the first manifestation in these patients and represent an important risk factor for fracture. The reduction of mechanical input on bone inhibits bone formation by osteoblasts and accelerates bone resorption by osteoclasts, leading to disuse osteoporosis. We report three cases of individuals from the same family with a diagnosis of CMT with severe tibia bone microarchitecture deterioration assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT). This affectation was exclusive to the tibia; the radius remained undamaged, showing the consequences of the lack of mobility and mechanical stimulation. Physical activity and rehabilitation, in addition to adequate calcium and vitamin D supplementation, may play an essential role in the management of this disease.

Evaluation of bovine sperm telomere length and association with semen quality

The study aimed to evaluate if the sperm telomere length can be considered as a new biomarker for sperm quality in bulls. Sperm Telomere Length was evaluated by Monochrome Multiplex Quantitative PCR in group A (n = 8) and group B (n = 8) bulls, classified according to standard semen analysis. Also, this parameter was measured before and after Percoll gradient separation within bulls that produced semen of satisfactory quality. Sperm telomere length, measured as T/S ratio (average ratio of telomere repeats copy number to a single copy gene), was higher in group A than in group B bulls (0.77 ± 0.03 vs 0.43 ± 0.06; P < 0.01). Sperm telomere length was positively correlated with motility, viability and membrane integrity, and it was negatively correlated with sperm anomalies. Furthermore, Percoll gradient selected sperms with higher T/S ratio than unselected sperms (1.19 ± 0.02 vs 0.67 ± 0.03). These results suggest that sperm telomere length can be used as a new marker of bovine semen quality.

Crocin Improves the Quality of Cryopreserved Goat Semen in Different Breeds

The effect of crocin in the semen extender before cryopreservation was evaluated on sperm parameters of 20 bucks of five different breeds: Garganica (GA), Jonica (JO), Maltese (MA), Mediterranean Red (MR) and Saanen (SA). Semen samples were centrifuged, to remove seminal plasma, divided in two aliquots and diluted with Tris-egg-yolk-based extender, containing 0 (control group) and 1 mM crocin. Crocin concentration was established after a preliminary dose trial. On fresh and frozen-thawed sperm, motility, viability, morphology, membrane integrity, DNA fragmentation and ROS levels were evaluated. The freezing process led to a decrease (p < 0.05) in all the sperm parameters recorded, confirming the deleterious effect of cryopreservation on goat semen. The most interesting result regarding the inclusion of crocin in the extender before cryopreservation was as follows: Crocin significantly improved (p < 0.05) sperm motility in all breeds, except for Mediterranean Red, compared to the control group. Furthermore, 1 mM crocin reduced percentage of spermatozoa with DNA fragmentation with a marked decrement (p < 0.05) in Garganica and Saanen, as compared to the control group. Finally, intracellular ROS decreased (p < 0.01) in the crocin-treated sperm of all breeds, as compared to the control. In conclusion, supplementation of 1 mM crocin in the extender decreased oxidative stress, improving sperm motility and the DNA integrity of frozen-thawed sperm in different breeds.

Changes in Bull Semen Metabolome in Relation to Cryopreservation and Fertility

Semen cryopreservation determines several sperm damages, including the loss of fertility-associated proteins. The purpose of the study was to compare the metabolite contents in bovine sperm and seminal plasma before and after cryopreservation, and between high- and low-fertility bulls in vitro. Forty-eight ejaculates, collected from eight bulls (six per bull), were analyzed by liquid chromatography-mass spectrometry. Cryopreservation resulted in an over-expression of lysophosphatidylcholine (0:0/18:2(9Z,12Z)) in seminal plasma. In addition, higher levels of glycine betaine and pyro-l-glutaminyl-l-glutamine were observed in cryopreserved compared to fresh spermatozoa. The fresh seminal plasma of high-fertility bulls showed an over-expression of l-acetylcarnitine, glycerol tripropanoate, 2,3-diacetoxypropyl stearate and glycerophosphocholine, and an under-expression of lysophosphatidylcholine and butyrylcarnitine, compared to low-fertility bulls. Higher levels of glycerophosphocholine and lysophosphatidylcholine (16:0/0:0) were recorded in fresh spermatozoa from high-fertility bulls. In high-fertility bulls, a greater content of glycerophosphocholine and lower levels of butyrylcarnitine, glycine betaine and l-carnitine were found in cryopreserved seminal plasma, and lower levels of glycine betaine were detected in cryopreserved spermatozoa. In conclusion, cryopreservation affects bovine semen metabolome at both plasmatic and cellular compartments, and metabolic profile differs between high- and low-fertility bulls.

Analysis of meiotic segregation by triple-color fish on both total and motile sperm fractions in a t(1p;18) river buffalo bull

Chromosomal aberrations are relatively frequent pathologies in both humans and animals. Among them, translocations present a specific meiotic segregation pattern able to give a higher percentage of unbalanced gametes that can induce fertility problems. In this study, the meiotic segregation patterns of 1p, 1q and 18 Bubalus bubalis chromosomes were analyzed in both total sperm fraction and motile sperm fraction of a t(1p;18) carrier and a control bulls by triple-color FISH analysis with a pool of specific BAC probes. The frequencies of each total sperm fraction products in the carrier resulting from alternate, adjacent I, adjacent II and 3:1 segregation were 39%, 20%, 1% and 38%, respectively. On the other hand, the frequencies of each motile sperm fraction products in the carrier resulting from alternate, adjacent I, adjacent II and 3:1 segregation were 93%, 5%, 0% and 2%, respectively. The frequencies of normal sperms in the carrier were 27% and 69% in total sperm fraction and motile sperm fraction, respectively. The frequencies detected in motile sperm fraction were also validated by comparison with bull’s progeny. To our knowledge, this is the first report on the meiotic segregation patterns in motile sperm fractions of B. bubalis bull carrying a chromosomal translocation. These data suggest that translocation has a very limited effect on aneuploidy in the gametes, and therefore, on the reproductive abilities of the bull.

Effect of caspase inhibitor Z-VAD-FMK on bovine sperm cryotolerance

The aim of this study was to evaluate the treatment of bovine semen with the pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK), before or after freezing on semen quality. After the initial assessment, sperm from 4 bulls were pooled (Experiment 1) and cryopreserved in BioXcell containing 0, 20 and 100 μM Z-VAD-FMK. After thawing semen viability, motility, membrane integrity, as well as DNA fragmentation and ΔΨm were evaluated. In Experiment 2, bovine frozen/thawed sperm were incubated for 1 hr with 0, 20 and 100 µM Z-VAD-FMK before assessing the semen quality. The treatment with Z -VAD-FMK before cryopreservation improved post-thawing sperm motility compared to the control group (p < .05), while no differences were recorded in sperm viability and membrane integrity among groups (on average 86.8 ± 1.5 and 69.1 ± 1.4, respectively). Interestingly, at the highest concentration, DNA fragmentation decreased (p < .05), while the percentage of spermatozoa with high ΔΨm increased (p < .05). The results of Experiment 2 showed that 1-hr treatment with Z-VAD-FMK did not affect sperm motility and viability (on average 63.4 ± 5.8 and 83.7.1 ± 1.2, respectively). However, Z-VAD-FMK improved sperm membrane integrity (p < .05) and at the highest concentration tested decreased the proportion of sperm showing DNA fragmentation (p < .05). No differences were recorded in the percentage of spermatozoa with high ΔΨm (on average 57.0 ± 11.4). In conclusion, the treatment with 100 µM of the caspase inhibitor Z-VAD-FMK before freezing increased bovine sperm mass motility and ΔΨm, while decreasing sperm DNA fragmentation. Treatment of semen after thawing with 100 µM Z-VAD-FMK improved sperm membrane integrity and reduced DNA fragmentation.

142 Metabolomic analysis of fresh and frozen bovine seminal plasma: A preliminary study

Sperm cryopreservation is essential for assisted reproduction; however, freezing induces biochemical and physical damage to the sperm membrane structures, negatively affecting sperm fertilising ability (Castro et al. 2006 J. Anim. Sci. Biotechnol. 5, 1-9). Metabolomics is the study of small molecules, commonly known as metabolites, which play essential roles in biological systems. Emerging research in the field of metabolomics showed a potential role in identifying male fertility biomarkers (Bieniek et al. 2016 Asian J. Androl. 18, 426-433). Metabolites present in the seminal plasma play several roles related to sperm motility, sperm membrane protection from oxidative stress, and regulation of metabolic activity (Therien et al. 1995 Biol. Reprod. 52, 1372-1379). However, the extent of metabolite changes in seminal plasma during cryopreservation is still not well known. Therefore, the aim of this study was to evaluate the differences of the seminal plasma metabolites between fresh and frozen bovine sperm. Four ejaculates from eight Holstein (Bos taurus) bulls (4-6 years age) maintained at an authorised national semen collection center (Centro Tori Chiacchierini, Civitella D’Arna, Italy) under uniform management conditions were collected weekly using an artificial vagina (IMV Technologies). Each ejaculate was split into two aliquots (one fresh and one frozen) at −20°C for at least 2h. Seminal plasma from fresh (immediately) and frozen-thawed semen was separated from sperm by centrifugation (1600×g for 10min), and supernatants were then transferred to a 2-mL tube and stored at −80°C until use. After methanol extraction of metabolites, samples were centrifuged at 6400×g for 30min at 4°C, and supernatants were analysed using a liquid chromatography-mass spectrometry (LC-MS; Agilent 1260 HPLC; Agilent Technologies) system with an autosampler and a binary pump coupled to an Agilent Q-TOF 6540 (Agilent Technologies). Univariate analyses of the data were performed using bioinformatics approaches. The differences between fresh and frozen seminal plasma samples were analysed using a paired Student's t-test. Twenty-three metabolites were found in both fresh and frozen seminal plasma samples, out of which eight were significantly different (P&lt;0.05) between the two groups; among these, hypotaurine, ceramide, and isoindoline were identified. In particular, hypotaurine and ceramide were downregulated, whereas isoindoline was upregulated in fresh samples compared with frozen samples. To the best of our knowledge, this is the first study to identify seminal plasma metabolites in fresh and frozen samples by using LC-MS. In order to ensure the reliability and accuracy of results, the validation of the method used in the analysis of biosamples is still in progress, as is the evaluation of the metabolic profile in sperm cells. In conclusion, the results of this study suggest that LC-MS can be a promising screening tool to detect metabolites potentially associated with bull fertility.

148 Bull spermatozoa uptake of extracellular vesicles from bovine seminal plasma

Extracellular vesicles (EV) are important mediators of intercellular communication because they transfer microRNA (miRNA) that are able to repress translation of mRNA. Their presence in seminal plasma suggests a role in sperm fertility. It is known that bull seminal plasma contains fertility-associated proteins that are predictive of high and low fertility (Killian et al. 1993 Biol. Reprod. 49, 1202-1207). In addition, a difference in miRNA content between high and low spermatozoa motility has been observed in bulls, highlighting a potential role of EV on fertility (Capra et al. 2017 BMC Genom. 18, 14). We hypothesised that co-incubation of sperm of low-fertility bulls with EV isolated from the seminal plasma of high-fertility bulls could improve their fertility. Before testing this hypothesis, a preliminary study was carried out to investigate the presence and type of EV in bovine seminal plasma and their interaction with spermatozoa. Ejaculates of eight Holstein bulls collected weekly by artificial vagina were centrifuged at 1600×g for 10min to pellet spermatozoa and then centrifuged again at 2400×g for 30min to eliminate cell debris and large vesicles. After centrifugation, supernatants were collected and filtered twice (0.45 and 0.22µm) and stored at −80°C. A double ultracentrifugation at 100 000×g for 1h was performed, and pellets resuspended in a small volume of Tris buffer were kept at −80°C until used. Three ejaculates of the same bull were pooled to detect the concentration and size of EV by Nanosight Instruments. To trace the interaction with spermatozoa by fluorescence microscopy, EV were labeled with PKH26 dye and a dose-response curve in three replicates was performed. A suspension of 1×106 spermmL−1 was co-incubated with 200 or 400×106 EV labelled with pKH26 for 30, 60, 90, 120, 150, and 180min at 38.5°C. The end point of incubation was at 24h. Internalisation of EV was assessed using confocal microscopy. Our results showed that the size of EV ranged from 145.1 to 187.7nm, with an average of 166±29nm. For all seminal plasma samples, the number of EV ranged from 3.62 to 6.08×1013 particlesmL−1, with an average of 4.37±0.61×1013. Based on size, these EV can be categorised as shedding vesicles. Confocal microscopy was set to take fluorescent images at different planes scanned every 0.12µm from top to bottom of the spermatozoa. Our results showed that no fluorescence signal was detectable after co-incubation with 200×106 EV. At the concentration of 400×106 EV, up to 60min no signal was detectable, whereas at 90min spermatozoa showed a fine granular fluorescent pattern within the intermediate portion. At 120min, the signal was within the acrosome, and at 180min the spermatozoa were stained for the whole length, supposing a distribution of incorporated EV throughout all the cell. At 24h, the fluorescence signal decreased. In conclusion, this is the first study to demonstrate that bull spermatozoa incorporate EV from bull semen. We hypothesise that a transfer of molecules, such as miRNA and other noncoding RNA molecules, from EV to spermatozoa is probably involved in sperm fertility.

27 Effects of the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone on frozen - thawed bovine sperm

Semen cryopreservation is critical for appropriate planning of both AI and IVF trials, improving the benefit:cost ratio. However, cryopreservation induces damage in mammalian spermatozoa, resulting in decreased fertility (Medeiros et al. 2002 Theriogenology 57, 327-344). It is known that cryopreservation and thawing induce apoptosis in a variety of cells, including bovine sperm (Anzar et al. 2002 Biol. Reprod. 66, 354-360). Cryotolerance of in vitro-produced bovine embryos was recently improved by inhibiting apoptosis using a caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (ZVAD-FMK), during vitrification and subsequent culture (Pero et al. 2018 Theriogenology 108, 127-135). The aim of this work was to evaluate whether treatment of bovine frozen-thawed sperm with the caspase inhibitor Z-VAD-FMK may prevent aberrant apoptosis and consequently improve sperm viability. Six ejaculates from 12 bulls were used for the trial. Semen was diluted at 37°C with BioXcell extender (BioXcell, West Lebanon, NH) to a final concentration of 30×106 spermatozoa mL−1, and straws were kept at 4°C for 4h and then frozen in an automated system. After thawing, Percoll-separated spermatozoa were incubated at 37°C for 1h with 0, 20, and 100µM ZVAD-FMK. Sperm viability and membrane integrity were assessed by Trypan Blue/Giemsa and hypo-osmotic swelling test, respectively, as previously described (Longobardi et al. 2017 Theriogenology 88, 1-8). Sperm motility was examined by phase contrast microscopy at 40× magnification on a thermoregulated stage at 37°C. Apoptosis was evaluated by TUNEL technique, which assesses DNA fragmentation (Takeda et al. 201561, 185-190). The mitochondrial membrane potential was then assessed by flow cytometric analysis with the mitochondrial probe JC-1 (Garner and Thomas 1999Mol. Reprod. Dev. 53, 222-229). Data were analysed by ANOVA using least significant difference as post-hoc test. The treatment of bovine frozen-thawed sperm with 100µM ZVAD-FMK decreased the percentage of sperm exhibiting DNA fragmentation (17.8±1.1, 13.3±2.8, and 10.5±2.5 with 0, 20, and 100µM ZVAD, respectively; P&lt;0.05). Moreover, both concentrations of ZVAD-FMK increased the percentage of hypo-osmotic swelling test+ sperm, indicating improved membrane integrity compared with the control (60.5±3.5, 70.9±2.1, and 74.3±2.1 with 0, 20, and 100µM ZVAD-FMK, respectively; P&lt;0.01). However, no differences were found in sperm viability (82.3±0.5, 84.6±1.0, and 84.3±2.1 with 0, 20, and 100µM ZVAD-FMK, respectively) and motility (60.0±2.9, 62.5±3.4, and 67.5±2.1 with 0, 20, and 100µM ZVAD-FMK, respectively). Furthermore, no differences were observed among groups in the percentage of sperm exhibiting normal mitochondrial membrane potential (62.4±12.7, 57.9±12.8, and 50.8±8.8 with 0, 20, and 100µM ZVAD, respectively). In conclusion, caspase inhibition with 100µM ZVAD-FMK after thawing was effective in reducing sperm DNA fragmentation and increasing sperm membrane integrity, suggesting a beneficial effect on fertility. However, as the other fertility-related parameters did not improve, further investigations are required to draw definite conclusions.

Cholesterol-loaded cyclodextrins prevent cryocapacitation damages in buffalo (Bubalus bubalis) cryopreserved sperm

The aim of this study was to investigate the effect of cholesterol-loaded cyclodextrins (CLC) on motility, viability, capacitation status, and in vivo fertility of buffalo frozen-thawed sperm. After the initial semen assessment, buffalo sperm were diluted in BULLXcell extender containing 0- (control), 1.5-, and 3-mg/mL CLC and cryopreserved. At thawing, sperm motility was evaluated by phase contrast microscopy, and viability-capacitation status was assessed by Hoechst 33258-chlortetracycline (CTC) assay. Capacitation status was also evaluated by an indirect immunofluorescence assay to localize phosphotyrosine-containing proteins. Moreover, buffaloes were artificial inseminated to assess the in vivo-fertilizing potential of CLC-treated semen. No differences among control, 1.5-, and 3-mg/mL CLC-treated groups were recorded in both sperm motility (66.5 ± 5.6, 68.8 ± 4.8, and 68.8 ± 4.8, respectively) and viability (86.5 ± 1.9, 87.6 ± 1.5, 88.4 ± 2.3, respectively). However, the extender supplementation with CLC significantly reduced sperm cryocapacitation. Indeed, CLC treatment decreased (P < 0.01) the proportion of sperm showing the CTC pattern B (capacitated sperm) compared with the control (69.6 ± 3.4, 37.8 ± 1.5, and 51.3 ± 4.7, respectively, with 0, 1.5-, and 3-mg/mL CLC; P < 0.01). Furthermore, the percentage of sperm displaying tyrosine-phosphorylated pattern EA (i.e. high capacitation level) was reduced (P < 0.01) in both CLC-treated groups (10.8 ± 3.3 and 5.6 ± 1.6, respectively, with 1.5- and 3-mg/mL CLC) compared with the control (37.3 ± 6.9), reaching values similar to those recorded in fresh semen (11.0 ± 3.5). In addition, treating sperm with 3-mg/mL CLC increased (P < 0.01) the percentage of nonfluorescent (pattern NF), i.e., non-capacitated sperm (41.8 ± 3.6) compared with fresh semen (11.0 ± 6.9). No differences were recorded in pregnancy rates at 60 days post-artificial insemination among control, 1.5- and 3-mg/mL CLC groups (59.7%, 65.6%, and 56.9%, respectively). In conclusion, CLC treatment of buffalo sperm strongly decreases sperm cryocapacitation damages, without affecting the in vivo fertilizing capability.

164 CARNITINE IMPROVES POST-THAWING SPERM MOTILITY BY INCREASING ADENOSINE TRIPHOSPHATE CONTENT IN BUFFALO (Bubalus bubalis)

Semen cryopreservation plays a critical role for a wide application of both AI and in vitro embryo production in buffalo. In this species, spermatozoa are more susceptible to hazards during freezing and thawing than cattle spermatozoa, thus resulting in lower fertilizing potential (Andrabi et al. 2008 Anim. Reprod. Sci. 104, 427–433). Carnitine is a quaternary ammonium compound with antioxidant capacities, able to reduce the availability of lipids for peroxidation by transporting fatty acids into the mitochondria for β-oxidation to generate adenosine triphosphate (ATP) energy (Tanphaichitr and Leelahagul 1993 Nutrition 9, 246–54). It is known that cryopreservation processes decreases the intracellular concentration of carnitine in spermatozoa (Reyes-Moreno et al. 2000 J. Androl. 21, 876–86). In cattle, supplementation of semen extender with carnitine improves sperm motility and DNA integrity (Bucak et al. 2010 Cryobiology 61, 248–53). The aim of this study was to evaluate whether supplementation of semen extender with carnitine would increase ATP content in buffalo sperm and affect post-thawing motility. Eight ejaculates from 4 bulls were used for the trial. Each ejaculate was split into 3 equal aliquots and diluted at 37°C with BioXcell extender containing 0 (control), 2.5, and 7.5 mM carnitine to a final concentration of 30 × 106 spermatozoa/mL. After 4 h at 4°C, the straws were frozen in an automated system. At thawing, sperm motility was evaluated by phase contrast microscopy at 40× magnification (Gillan et al. 2008 Anim. Reprod. Sci. 103, 201–204). Adenosine triphosphate content was measured using a Colourimetric ATP Assay Kit (Biovision, Milpitas, CA, USA). Briefly, Percoll-separated spermatozoa were homogenised and then deproteinized using 10-kDa spin columns. Samples were incubated at RT for 30 min and absorbance was measured at 570 nM in a microplate reader. Differences in sperm motility and ATP content among groups were analysed by ANOVA. Both concentrations of carnitine increased post-thawing sperm motility compared with the control (44.4 ± 3.5, 53.1 ± 3.9, and 52.5 ± 3.6, respectively, with 0, 2.5, and 7.5 mM carnitine; P < 0.05). Interestingly, carnitine increased ATP content of buffalo frozen–thawed sperm in a dose-dependent manner (4.1 ± 0.1, 5.3 ± 0.1, and 8.2 ± 0.4 nM × 108 sperm, respectively, with 0, 2.5, and 7.5 mM carnitine; P < 0.01). In conclusion, the enrichment of semen extender with carnitine improved post-thawing motility of buffalo sperm by boosting mitochondrial ATP production, hence providing energy for use by spermatozoa.

51 CASPASE-3 INHIBITOR Z-VAD-FMK ENHANCES CRYOTOLERANCE OF IN VITRO-PRODUCED BOVINE PRE-IMPLANTATION EMBRYOS

In vitro-produced (IVP) bovine embryos are still less viable and resistant to cryopreservation than their in vivo counterparts. Cryopreservation induces cell degeneration through the apoptotic pathway in bovine oocytes and embryos (Men et al. 2003 Cryobiology 47, 73–81). Apoptosis can be prevented by inhibition of caspase activity, leading to improved cryosurvival in mammalian cells (Stroh et al. 2002 FASEB J. 16, 1651–3). Interestingly, cryotolerance of porcine embryos was improved by inhibiting apoptosis using a caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK) during vitrification and subsequent culture (Men et al. 2006 Theriogenology 66, 2008–16). Aim of this work was to evaluate whether cryotolerance of bovine IVP embryos may be improved by using Z-VAD-FMK during cryopreservation and post-warming in vitro culture. Abattoir-derived bovine oocytes (n = 753, over 4 replicates) were in vitro matured and fertilized according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347–55). Twenty hours after IVF, presumptive zygotes were cultured in SOF medium at 39°C with 5% CO2, 7% O2, and 88% N2. On Day 7, embryo yields were assessed and blastocysts (except the hatched blastocysts) were randomly divided in 2 groups: vitrification and post-warming culture in presence (n = 60) or absence (n = 54) of 20 µM Z-VAD-FMK. Vitrification was carried out by Cryotop in 16.5% ethylene glycol, 16.5% DMSO, and 0.5 M sucrose (Rubessa et al. 2011 Theriogenology 76, 1347–55). Blastocysts were warmed in decreasing sucrose solutions (0.25 M for 1 min and 0.15 M for 5 min) and cultured for 2 days. Resistance to cryopreservation was evaluated by assessing the survival rate, based on morphological criteria and hatching rate after 48 h culture. Furthermore, TUNEL staining was used to evaluate the total cell (TC) number and the apoptotic rate of vitrified blastocysts after 48-h post-warming culture. Differences between groups in survival and hatching rates after 48-h post-warming culture were analysed by Chi-squared test, whereas differences in TC number and in number and percentage of apoptotic cells were analysed by Student’s t-test. Inhibition of caspase activity induced by Z-VAD-FMK increased embryo cryotolerance, as indicated by higher survival (92.6 v. 55.0%; P < 0.01) and hatching rates (40.7 v. 23.3%; P < 0.05) after 48 h of post-warming culture. Furthermore, Z-VAD-FMK decreased both the average number (7.1 ± 0.6 v. 4.2 ± 0.3; P < 0.01) and the percentage (6.3 ± 0.6 v. 3.0 ± 0.2; P < 0.01) of apoptotic cells in blastocysts. No differences were recorded in TC number between groups (on average, 128.90 ± 1.6). These results suggest that addition of 20 µM Z-VAD-FMK during vitrification/warming and post-warming culture significantly inhibits apoptosis (DNA fragmentation) and improves the cryotolerance of IVP bovine embryos.

Impact of 3-Monthly Vitamin D Supplementation Plus Exercise on Survival after Surgery for Osteoporotic Hip Fracture in Adult Patients over 50 Years: A Pragmatic Randomized, Partially Blinded, Controlled Trial

OBJECTIVE

To determine whether 3-monthly supplementation of an oral vitamin D widely used in Spain (calcifediol) plus daily exercise could influence survival at one and four years after surgery for osteoporotic hip fracture.

DESIGN

A pragmatic, randomized, partially single-blind placebo-controlled study.

SETTING

Patients admitted to a tertiary university hospital for acute hip fracture.

PARTICIPANTS

675 healthy adult patients undergoing surgery for osteoporotic hip fracture were recruited from January 2004 to December 2007.

INTERVENTION

Patients were randomized to receive either 3-monthly oral doses of 3 mg calcifediol (Hidroferol Choque®) or placebo in the 12 months postsurgery. Patients who received calcifediol were also given an exercise programme. The placebo group received standard health recommendations only.

MEASUREMENTS

The primary endpoint was survival at 1 year and at 4 year follow-up. We also recorded new fractures, medical complications and anti-osteoporotic treatment compliance.

RESULTS

We included a total of 88 patients, aged 62 to 99 years. Mean age was 82 years and 88.6% were women. At 12 months, 10 (11.3%) patients had died, 9 of them, from the non-intervention group. At 4 years after surgery, 20 (22.7%) had died, 3 (3.4%) from the intervention group and 17 (19.3%) from the non-intervention group. At this time, survival curve analysis showed 93% survival in the intervention group and 62% in the non-intervention group (p=0.001). At 12-month follow up, there were 18 new fractures, 9 in each group. The non-intervention group had more medical complications, with significant differences at visit 2 (p = 0.04) and 3 (p = 0.02) but not at visit 4 (p = 0.18). No significant differences between groups were found regarding treatment compliance.

CONCLUSION

3-monthly, oral supplements of 3 mg calcifediol plus daily exercise improved survival at one-year and four-year follow up after surgery for an osteoporotic hip fracture.

Effect of Relaxin on Fertility Parameters of Frozen-Thawed Buffalo (Bubalus bubalis) Sperm

The aim of this work was to evaluate the effect of relaxin on fertility parameters of buffalo frozen/thawed sperm. Sperm were incubated in the absence of capacitating agents (negative control), with a known capacitating agent such as heparin (positive control) and with 50 and 100 ng/ml relaxin for 2 and 4 h. Sperm viability, motility, capacitation and the effect of relaxin on the fertilizing ability after heterologous IVF were evaluated. Although viability was not affected, relaxin increased (p < 0.05) sperm motility compared to the negative and positive controls both after 2 h (60.0 ± 2.0, 60.0 ± 3.1, 68.3 ± 1.7 and 69.4 ± 2.7, respectively, in negative control, positive control, 50 and 100 ng/ml relaxin) and 4 h (55.0 ± 2.5, 53.3 ± 3.0, 62.2 ± 3.0 and 65.0 ± 3.2, respectively, in negative control, positive control, 50 and 100 ng/ml relaxin) incubation. When sperm were incubated with both 100 ng/ml relaxin and heparin, a decrease (p < 0.01) of pattern A, that is low capacitation level, was observed compared to the negative control both after 2 h (54.4, 34.3 and 36.4%, respectively, in negative control, positive control and 100 ng/ml relaxin) and 4 h (51.9, 35.0 and 34.3%, respectively, in negative control, positive control and 100 ng/ml relaxin). Moreover, an increase (p < 0.01) of pattern EA, that is high capacitation level, was recorded with 100 ng/ml relaxin and heparin compared to the negative control both after 2 h (44.1, 59.3 and 57.7%, respectively, in negative control, positive control and 100 ng/ml relaxin) and after 4 h (43.0, 54.4 and 56.0%, respectively, in negative control, positive control and 100 ng/ml relaxin). Finally, relaxin increased (p < 0.01) cleavage rate compared to the negative control (57.1 ± 4.4, 72.5 ± 6.0, 71.4 ± 5.5 and 73.6 ± 2.9, respectively, in negative control, positive control, 50 and 100 ng/ml relaxin). In conclusion, relaxin has a beneficial effect on motility, capacitation and fertilizing ability of frozen-thawed buffalo sperm.

88 ENRICHMENT OF CULTURE MEDIUM WITH CROCETIN IMPROVES IN VITRO EMBRYO DEVELOPMENT IN CATTLE

The high incidence of developmental failure of bovine in vitro-produced embryos is due to suboptimal culture conditions that induce oxidative stress. Indeed, increased oxidative stress is one of the main factors affecting in vitro mammalian embryo development, decreasing the viability of IVP embryos. It is known that saffron has a powerful antioxidant capacity, mainly due to its active components crocin and crocetin. The aim of this study was to evaluate whether enriching the in vitro culture medium with crocetin improves in vitro embryo production efficiency in cattle. The range of concentrations of crocetin was chosen after a preliminary dose response trial (322 total presumptive zygotes were cultured with 0, 1, 10, and 50 μM, over 2 replicates) that showed beneficial and deleterious effects, respectively, with the lowest and highest concentration compared with the control (36.6 ± 5.6, 57.4 ± 4.5, 46.4 ± 4.4, and 6.8 ± 3.7% blastocyst rates, respectively, with 0, 1, 10, and 50 μM; P < 0.01). Therefore, the range of concentrations to test was reduced. Abattoir-derived bovine oocytes (n = 832, over 4 replicates) were in vitro matured and fertilized according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Twenty hours after IVF, presumptive zygotes were cultured in SOF medium with 0 (control; n = 208), 1 μM (n = 208), 2.5 μM (n = 208), and 5 μM (n = 208), at 39°C under humidified air with 5% CO2, 7% O2, and 88% N2. The embryos obtained by the end of culture (i.e. on Day 7 post-IVF) were scored for quality, based on morphological criteria, and for developmental stage, as previously described (Robertson and Nelson 2010, Manual of the IETS, 86–105). The percentages of total transferable embryos and grade 1 and 2 blastocysts were recorded. As the chronology of development is a reliable parameter to assess quality, the percentage of fast-developing embryos (i.e. hatched and expanded blastocysts) was also compared among groups. Differences among groups were analysed by ANOVA, and Tukey method was used as a post-hoc test. Data are presented as means ± s.d. The supplementation of crocetin during culture did not affect cleavage rate (74.9 ± 6.3, 76.4 ± 8.4, 81.4 ± 4.3, and 76.4 ± 8.4%, respectively, with 0, 1, 2.5, and 5 μM). However, post-fertilization embryo development improved with 1 µM crocetin compared with the control, both in terms of total embryo output (43.8 ± 4.4, 61.1 ± 5.2, 50.4 ± 6.7, and 53.3 ± 7.3%, respectively, with 0, 1, 2.5, and 5 μM; P < 0.01) and grade 1 and 2 blastocysts (41.0 ± 3.6, 54.3 ± 5.4, 46.2 ± 6.7, and 49.4 ± 6.5%, respectively, with 0, 1, 2.5, and 5 μM; P < 0.05), whereas no differences were observed among the other groups. Moreover, the percentage of fast developing embryos increased with 1 µM (P < 0.05) crocetin compared with the control, with no other differences recorded among groups (17.7 ± 5.8, 34.7 ± 5.7, 24.9 ± 5.1, and 28.7 ± 7.8%, respectively, with 0, 1, 2.5, and 5 μM). In conclusion, these results demonstrated a beneficial effect of low concentrations of crocetin (1 μM) during culture both on blastocyst yield and quality, as indicated by the improved chronology of embryo development.

40 CHOLESTEROL SUPPLEMENTATION REDUCES CRYOCAPACITATION DAMAGES IN BUFFALO (BUBALUS BUBALIS) SPERM

Buffalo sperm are more sensitive to cryopreservation and thawing-induced damages than cattle sperm, thus resulting in lower fertilizing ability. Cryopreservation induces considerable capacitation-like changes in buffalo sperm (Elkhawagah et al. 2014 J. Buffalo Sci. 3, 3–11). It is known that specific lipid mixtures, including cholesterol, stabilise and protect spermatozoa from freeze-thaw damage (Rajoriya et al. 2014 Vet. World. 7, 702–706). Therefore, the aim of this study was to investigate the effect of cholesterol loaded cyclodextrins (CLC) before cryopreservation on the capacitation status of buffalo frozen sperm. Four ejaculates from 4 bulls were selected, split in 3 aliquots, and diluted at 37°C with BULLXcell extender, containing 0 (control), 1.5, and 3 mg mL–1 CLC, to a final concentration of 30 × 106 sperm mL–1. Cyclodextrin was loaded with cholesterol as described earlier (Purdy and Graham 2004 Cryobiology 48(1), 36–45). The aliquots were frozen according to standard procedures. At thawing, sperm motility was evaluated by phase contrast microscopy, and viability and capacitation status were evaluated by Hoechst 33258/CTC. Briefly, Percoll separated spermatozoa were incubated with 1% (wt/vol) Hoechst 33258 in a protein-free medium. After centrifugation (900 × g, 5 min), the pellet was resuspended in CTC staining solution (750 mM CTC, 5 mM cysteine in 130 mM NaCl, and 20 mM Tris acid, pH 7.8), fixed with glutaraldehyde (12.5% vol/vol), and placed on a slide. At least 100 sperm per slide were analysed and classified into 1 of 3 CTC staining patterns: pattern F, with fluorescence over the entire sperm head (noncapacitated); pattern B, with a fluorescence-free band in the postacrosomal region (capacitated); pattern AR, with no acrosome and a thin band of fluorescence along the equatorial segment (acrosome reacted). Data were analysed by ANOVA. No differences among control, 1.5, and 3 mg mL–1 CLC-treated groups were recorded in both sperm motility (66.5 ± 5.6, 68.8 ± 4.8, and 68.8 ± 4.8, respectively) and viability (86.5 ± 1.9, 87.6 ± 1.5, 88.4 ± 2.3, respectively). The most interesting result arising was the strong reduction of sperm cryocapacitation observed when the extender was supplemented with CLC, as shown by the increased percentage of sperm displaying pattern F (28.6 ± 3.3, 61.5 ± 1.7, and 47.6 ± 4.3 in control, 1.5, and 3 mg mL–1 CLC groups, respectively; P < 0.01) and the decreased percentage of sperm displaying pattern B (69.6 ± 3.4, 37.8 ± 1.5, and 51.3 ± 4.7 in control, 1.5, and 3 mg mL–1 CLC groups, respectively; P < 0.01) compared with the control. The maximum beneficial effect on semen cryopreservation was recorded with the dose of 1.5 mg mL–1 CLC. However, no differences were detected in pattern AR that remained low in all groups (1.8 ± 0.7, 0.8 ± 0.4, and 1.1 ± 0.6 in the control, 1.5, and 3 mg mL–1 CLC groups, respectively). In conclusion, it was demonstrated that treating buffalo sperm with cholesterol before cryopreservation strongly decreases cryocapacitation damages, likely by stabilising sperm membrane, hence improving sperm quality.

263 ADDING RESVERATROL TO THE EXTENDER AFFECTS PROTEIN TYROSINE PHOSPHORYLATION IN BUFFALO SPERM

Cryopreservation induces remarkable capacitation- like changes in buffalo sperm (Kadirvel et al. 2011 Theriogenology 75, 1630–1639; Elkhawagah et al. 2014 J. Buffalo Sci. 3, 3–11). The aim of this study was to evaluate the effect of resveratrol, a natural phytoalexin with antioxidant properties, on capacitation status of frozen-thawed buffalo sperm, assessed by protein tyrosine phosphorylation assay. Three ejaculates from four bulls were used for the trial. Each ejaculate was split into two equal aliquots and diluted at 37°C with BioXcell extender containing no supplement (control) or 50 µM resveratrol, to a final concentration of 30 × 106 spermatozoa per mL. After 4 h at 4°C, straws were frozen in an automated system. Immediately after thawing, sperm motility was evaluated by phase-contrast microscopy, sperm viability by Trypan Blue/Giemsa staining and localization of phosphotyrosine proteins by indirect immunofluorescence, as described Kadirvel et al. (2011 Theriogenology 75, 1630–1639). Briefly, after thawing, semen was centrifuged (300 × g, 10 min), fixed in 2% formaldehyde for 1 h at 4°C, and sperm pellets were incubated overnight at 4°C in modified phosphate buffer saline containing 2% BSA. After centrifugation, sperm pellets were resuspended, diluted 1 : 10 in mPBS, smeared onto slides, air-dried, and permeabilized with absolute ethanol for 5 min. Then, spermatozoa were incubated with rabbit anti-phosphotyrosine primary antibody for 1 h at room temperature in a humid chamber. Slides were incubated with secondary antibody, FITC conjugated goat anti-rabbit IgG, for 1 h in a dark humid chamber at room temperature and mounted with 90% glycerol. A total of 100 spermatozoa were screened per slide and classified as described (Luño et al. 2013 Reproduction 146, 315–324): pattern A: uniform fluorescence over the entire acrosome (low capacitation level); pattern E: signal in the equatorial segment (medium capacitation level); and pattern EA: fluorescence at both equatorial and acrosomal areas (high capacitation level). Data were analysed by chi-square. There were no significant differences between control and treated groups for sperm motility (50.0 and 55.0%, respectively) or viability (77.4 and 72.9%). The percentage of sperm cells that did not exhibit fluorescence was very low (2.4 and 4.3% in the control and resveratrol groups, respectively). In resveratrol-treated group, pattern E was higher than the control (4.9 and 2.0%; P < 0.01). More interestingly, in the resveratrol-treated group, an increased percentage of sperm with pattern A (79.6 and 52.5%) and a decreased percentage of sperm with pattern EA (12.2 and 43.1%) were recorded. Based on decreased sperm with a high capacitation level (EA pattern) and increased sperm with low capacitation level (A pattern) at thawing, we concluded that adding resveratrol to semen extender before cryopreservation of buffalo was beneficial.

264 EFFECT OF SEASON ON CRYOCAPACITATION OF BUFFALO (BUBALUS BUBALIS) SEMEN

Buffalo are short-day breeders; at our latitudes, reproductive activity improves during autumn. Although extensive studies have been conducted on the female, seasonal variations were also reported on post-thaw motility and membrane integrity of buffalo sperm (Andrabi 2009 Reprod. Domest. Anim. 44, 552–569). It was reported that cryopreservation induces capacitation-like changes in buffalo spermatozoa, assessed by both chlortetracycline (CTC) fluorescent and protein tyrosine phosphorylation assays (Kadirvel et al. 2011 Theriogenology 75, 1630–1639; Elkhawagah et al. 2014 J. Buffalo Sci. 3, 3–11). The aim of this study was to evaluate the effect of season on cryocapacitation of buffalo semen. At least two ejaculates were collected from 4 bulls during 2 seasons with different daylength: spring (low season) and autumn (peak season). Each ejaculate was diluted at 37°C with BioXcell extender to a final concentration of 30 × 106 spermatozoa per mL. After 4 h at 4°C, straws were frozen in an automated system. Immediately after thawing, sperm motility was evaluated by phase-contrast microscopy and viability, as well as capacitation status, were assessed by CTC fluorescent staining, as reported (Kadirvel et al. 2011 Theriogenology 75, 1630–1639). Briefly, sperm suspensions were first stained with 0.1 µg mL–1 Hoechst 33258 for 2 min. Then, equal volumes of sperm suspension and CTC solution (750 mM CTC, 5 mM cysteine in 130 mM NaCl, and 20 mM Tris-HCl) were mixed at room temperature, and glutaraldehyde (12.5%) was added. Sperm suspensions were mounted on slides and stored at 4°C overnight (in the dark). Each sample was assessed twice under a microscope equipped with phase contrast and epifluorescent optics. At least 100 spermatozoa per slide were evaluated and classified into 3 CTC staining patterns: 1) uniform bright fluorescence over the entire head (uncapacitated spermatozoa, pattern F); 2) fluorescence-free band in the post-acrosomal region (capacitated spermatozoa, pattern B); and 3) dull fluorescence over the entire head, except for a thin punctuate band of fluorescence along the equatorial segment (acrosome-reacted spermatozoa, pattern AR). Data were analysed by chi-square. There were no differences in sperm viability between seasons (78.4 and 76.4%, respectively, in autumn and spring). However, post-thaw motility increased (P < 0.05) in autumn (60.0%) compared with spring (50.0%). The percentage of sperm displaying CTC pattern F increased in autumn compared with spring (40.5 and 27.3%, respectively; P < 0.01), whereas the percentage of sperm with both pattern B (57.9 and 66.6%, respectively; P < 0.01) and AR (1.6 and 6.1%, respectively; P < 0.01) decreased. The number of bulls and ejaculates used in this study was too low to draw definitive conclusions. However, these findings suggested that capacitation-like changes after sperm cryopreservation may be reduced during the favourable season in buffalo.

135 EFFECT OF L-ERGOTHIONEINE SUPPLEMENTATION DURING CULTURE ON IN VITRO EMBRYO DEVELOPMENT IN BUFFALO (BUBALUS BUBALIS)

It is known that in vitro mammalian embryo development is negatively affected by the increased oxidative stress occurring under culture conditions. The oxidative damage of cell components via reactive oxygen species interferes with proper cell function. Buffalo embryos are particularly sensitive to oxidative stress because of their high lipid content (Boni et al. 1992 Acta Med. Vet. 38, 153–161). l-Ergothioneine (LE) is a powerful scavenger of hydroxyl radicals (OH) and an inhibitor of iron or copper ion-dependent generation of OH from hydrogen peroxide (H2O2). The aim of this study was to evaluate whether enriching the in vitro-culture medium with LE improves in vitro embryo production efficiency in buffalo. Abattoir-derived buffalo oocytes (n = 854, over 6 replicates) were in vitro matured and fertilized according to standard procedures (Gasparrini et al. 2006 Theriogenology 65, 275–287). Twenty hours after IVF presumptive zygotes were cultured in SOFaa supplemented by 8 mg mL–1 BSA in a controlled gas atmosphere consisting of 5% CO2, 7% O2, 88% N2, in humidified air, at 38.5°C with 0 (control; n = 214), 0.05 mM LE (n = 217), 0.1 mM LE (n = 204), and 1 mM LE (n = 219). Cleavage rate was assessed at the time of change of culture (Day 5) and the cleaved elements were cultured for a further 2 days. The embryos obtained by the end of culture, i.e. on Day 7 post-IVF, were scored for quality, based on morphological criteria, and for developmental stage, as previously described (Robertson, Nelson 2010 Manual of the International Embryo Transfer Society 86–105). The percentages of total transferable embryos and Grade 1 and 2 blastocysts in relation to cleaved oocytes were recorded. Because the chronology of development is known to be one of the most reliable parameters for assessing quality, the percentage of fast-developing embryos, i.e. hatched and expanded blastocysts, was also recorded. Data were analysed by Chi-squared test. Cleavage rate was not affected by the treatment (71.4, 66.8, 68.7, and 63.0%, respectively, with 0, 0.05, 0.1, and 1 mM LE). The total embryo output increased in groups supplemented with 0.05 and 0.1 mM LE (31.3, 42.2, 43.8, and 21.7%, respectively, with 0, 0.05, 0.1, and 1 mM LE; P < 0.05). However, the enrichment of in vitro culture with 0.1 mM LE also increased the percentage of Grade 1 and 2 blastocysts compared with the control and to 1 mM LE (21.6, 30.9, 33.9, and 21.7%, respectively, with 0, 0.05, 0.1, and 1 mM LE; P < 0.05). Likewise, 0.1 mM LE gave higher percentages of fast developing embryos than the control and 1 mM LE groups. In conclusion, these results demonstrated a beneficial effect of LE during culture on buffalo in vitro embryo development. The dose response trial indicated that the optimal concentration is 0.1 mM that also influenced the chronology of development and hence embryo viability.

145 EFFECT OF RELAXIN ON FERTILIZING ABILITY OF BUFFALO SPERM

The aim of this work was to evaluate the effect of relaxin, known to improve fertility parameters of frozen-thawed sperm in other species (Miah et al. 2006 J. Reprod. Dev. 52, 773–779; Miah et al. 2007 Anim. Sci. J. 78, 495–502), on buffalo sperm motility, capacitation, and fertilizing capability. Frozen-thawed sperm from 2 bulls (4 replicates each) were separated by Percoll, diluted to a 20 × 106 mL–1 concentration and incubated in TALP medium in the absence of capacitating agents (negative control), in the presence of 10 μg mL–1 of heparin (positive control) and 100 ng mL–1 of relaxin for 2 h. Following incubation, sperm were exposed for 15 min to 60 mg mL–1 of lysophosphatidylcholine, a fusogenic agent known to induce the acrosome reaction only on capacitated sperm. To evaluate acrosome-reacted (AR) live sperm, cells were fixed and stained with Trypan blue-Giemsa (Kovacs and Foote 1992 Biotech. Histochem. 67, 119–124) and evaluated (800 sperm counted/group). Sperm motility was examined by a phase contrast microscope, whereas the fertilizing capability was evaluated by heterologous IVF. Abattoir-derived bovine oocytes (n = 258, 86 per group) were in vitro matured and fertilized according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347–1355) with buffalo sperm in the absence of capacitating agents and in the presence of 10 μg mL–1 of heparin and 100 ng mL–1 of relaxin. Twenty hours after IVF, presumptive zygotes were denuded and cultured in SOF for 24 h, when cleavage rate was evaluated and confirmed by fixation with absolute ethanol overnight and staining with 2.5 μg mL–1 of Hoechst 33342 after zona removal by pronase (2 mg mL–1) digestion. The differences in the percentages of AR sperm and cleavage among groups were analysed by a chi square test and those in sperm motility by Student's t-test. Acrosomal loss was observed in 10.8% of the sperm after thawing, which may indicate freezing-induced capacitation, and, hence, this value was detracted from the percentages of AR recorded following incubation. After 2 h of incubation, 100 ng mL–1 of relaxin significantly (P < 0.05) increased the percentages of live AR sperm (P < 0.05) compared with the negative control (31.3 ± 2.2 and 25.8 ± 2.8, respectively), with intermediate results in the positive control (27.0 ± 2.2). Motility was significantly improved (P < 0.05) when sperm were exposed to 100 ng mL–1 of relaxin compared with both the negative and positive control (73.7 ± 2.4, 60.0 ± 4.1, and 60.0 ± 7.1, respectively). A significant (P < 0.05) improvement of cleavage rate was recorded both in the positive control (71.5 ± 4.8) and in the group treated with 100 ng mL–1 of relaxin (70.7 ± 0.5) compared with negative control (52.1 ± 1.5). In conclusion, these preliminary results indicate that relaxin at the concentration of 100 ng mL–1 improves sperm motility, capacitation, and the IVF capability of buffalo sperm.

144 INFLUENCE OF REPEATED OVUM PICKUP ON BUFFALO WELFARE

The aim of this work was to evaluate the effect of repeated ovum pickup (OPU) on buffalo welfare. The OPU was carried out as previously described (Neglia et al. 2003 Theriogenology 59, 1123–1130) twice per week on 11 buffalo cows at 121 ± 15 days in milk for 2 months (end of October–end of December). Blood samples were collected before the beginning of the trial (time 0), after 1 month (time 1), and after 2 months (time 2) in animals that had undergone OPU and in control animals (n = 10) of the same herd. The following parameters of clinical immunology were evaluated on sera: haemolytic complement (Arya et al. 1992 Vet. Immunol. Immunopathol. 30, 411–418), lysozyme, bactericidal capacity (Amadori et al. 1997 J. Vet. Med. 44, 321–327), and haptoglobin (Phase Haptoglobin Colourimetric Assay kit, Tridelta Development Ltd., Maynooth, County Kildare, Ireland). Data, here reported as means ± s.e.m., were analysed by ANOVA taking into account treatment, time, and the interaction. The number of aspirated follicles and collected oocytes per buffalo per session was 6.6 ± 0.2 and 3.6 ± 0.2, respectively. Interestingly, the OPU treatment did not affect haptoglobin (a reliable marker of acute stress), lysozyme, complement, and bactericidal capacity, whereas the time influenced (P < 0.05) only the complement. In animals that had undergone OPU, no differences among times 0, 1, and 2 in lysozyme (3.9 ± 0.3, 4.0 ± 0.6, and 3.6 ± 0.4 μg mL–1, respectively), bactericidal capacity (92.8 ± 0.8, 92.1 ± 0.8, and 92.2 ± 0.9%, respectively), and haptoglobin (1.8 ± 0.4, 1.4 ± 0.2, and 1.9 ± 0.6 mg mL–1, respectively) were found. Likewise, similar values were recorded at times 0, 1, and 2 in the control group in lysozyme (3.2 ± 0.3, 2.9 ± 0.3, and 3.1 ± 0.8 μg mL–1, respectively), bactericidal capacity (94.2 ± 0.6, 93.0 ± 1.1, and 89.2 ± 3.2%, respectively), and haptoglobin (0.7 ± 0.5, 1.3 ± 0.5, and 1.4 ± 0.4 mg mL–1, respectively). A significant decrease (P < 0.05) of complement (UE/150 mL) in OPU-treated animals was recorded at times 1 (33.6 ± 1.4) and 2 (35.9 ± 2.9) compared to time 0 (67.3 ± 3.3). However, the same pattern was observed in the control (62.8 ± 4.0, 31.3 ± 0.3, and 31.0 ± 0.8, respectively at times 0, 1, and 2; P < 0.05). Therefore, it is not possible to rule out that the decrease was due to other factors, such as the cold winter temperatures incoming, as previously reported. Furthermore, the values recorded at times 1 and 2 fall in the physiological ranges of the species (De Carlo et al. 2011 Joint Annual Meeting, Riccione, Italy). During the whole period of the experiment (and few weeks after), there were neither signs of behavioural modifications nor clinical signs of any disease. Furthermore, there were no differences in average daily milk production between treated and control buffaloes both at the start (9.1 ± 0.8 v. 9.4 ± 0.8) and at the end of the trial (7.6 ± 0.6 v. 6.5 ± 0.7), and all the animals that had undergone OPU conceived within 113.0 ± 25.4 days from the last OPU session. These preliminary results indicate that a regimen of OPU carried out twice per week for 2 months do not affect the welfare of buffaloes.

132 RESVERATROL DURING IN VITRO CULTURE IMPROVES CRYOTOLERANCE OF IN VITRO PRODUCED BOVINE EMBRYOS

Despite the great improvement of in vitro embryo production (IVEP) efficiency recorded over the years in cattle, the in vitro produced (IVP) embryos are still less viable and resistant to cryopreservation than their in vivo counterparts. One of the major factor impairing in vitro embryo development is oxidative stress. Resveratrol is an important antioxidant polyphenolic compound found in several vegetal sources, that contributes to red wine’s beneficial effects on the prevention of human cardiovascular disease. Recently, the interest in resveratrol has increased exponentially following the major findings that this molecule has positive effects on cancer chemoprevention, cardioprotection, inflammatory processes, several aspects of metabolism, leading to increased lifespan of various organisms from yeasts to vertebrates (Pirola et al. 2008 IUBMB Life 60, 323–332). A positive effect of resveratrol on in vitro embryonic development was demonstrated in swine (Lee et al. 2010 J. Reprod. Dev. 56, 330–335). The aim of this study was to evaluate whether supplementation of culture medium with resveratrol improves in vitro blastocyst development and the embryo resistance to cryopreservation in cattle. A preliminary dose response trial indicated that the optimal concentration in the range tested (from 0.5 to 10 µM) was 0.5 µM, with evident toxic effects at concentration higher than 5 µM. Abattoir-derived oocytes (n = 581, over 5 replicates) were matured and fertilized in vitro according to our standard procedure (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Twenty hours after IVF, presumptive zygotes were cultured in SOF medium, supplemented with 5% bovine serum, in the absence (control, n = 271) or presence of 0.5 µM resveratrol (n = 310) at 39°C under humidified air with 5% CO2, 7% O2, and 88% N2. On Day 7 (IVF = Day 0), embryo yields were assessed and the blastocysts (except the hatched blastocysts) were vitrified by cryotop in 16.5% ethylene glycol, 16.5% dimethyl sulfoxide (DMSO), and 0.5M sucrose (Rubessa et al. 2011). The resistance to cryopreservation was evaluated by assessing the survival rate, on the basis of morphological criteria, and hatching rate after 48 h culture. Data were analyzed by chi-square test. Resveratrol supplementation during culture did not affect either cleavage (69.1 v. 72.0%, in the control and resveratrol groups, respectively) or blastocyst yields (38.3 v. 36.3%, in the control and resveratrol groups, respectively). However, treatment with resveratrol increased the cryotolerance of IVP embryos, as indicated by higher survival rates (74.7 v. 88.4%, in the control and resveratrol groups, respectively; P < 0.05) and hatching rates (35.1 v. 53.8%, in the control and resveratrol groups, respectively; P = 0.06) at 48 h. In conclusion, these results demonstrated that resveratrol supplementation during culture improves the quality, and hence the resistance to cryopreservation, of IVP bovine embryos.

133 L-CARNITINE DURING IN VITRO CULTURE ENHANCES THE CRYOTOLERANCE OF BUFFALO (BUBALUS BUBALIS) IN VITRO-DERIVED EMBRYOS

In buffalo, in vitro embryo production (IVEP) technology is the best tool to improve the genetic merit through the maternal lineage. A major limitation of IVEP technology in buffalo species is the poor cryotolerance of the embryos, likely due to their high lipid content (Gasparrini 2002 Theriogenology 57, 237–256). It was previously demonstrated that supplementing bovine culture media with L-carnitine, a cofactor of β-oxidation, improves in vitro embryo development (Sutton-McDowall et al. 2012 Theriogenology 77, 1632–1641). The aim of this work was to evaluate whether L-carnitine supplementation during in vitro culture (IVC) improves blastocyst development and cryotolerance of in vitro produced buffalo embryos. After a preliminary dose response trial, we selected the concentration of 0.25 mM for the experiment. Cumulus–oocytes complexes (n = 288, over 4 replicates), recovered from slaughtered animals, were matured and fertilized in vitro according to our standard procedures (Gasparrini et al. 2006 Theriogenology 65, 275–287). On Day 1 (Day 0 = IVF), zygotes were cultured in SOF supplemented with 8 mg mL–1 BSA, in the absence (control, n = 143) or presence of 0.25 mM L-carnitine (n = 145). In vitro culture was carried out at 38.5°C under 5% CO2, 7% O2, and 88% N2. Cleavage rate was evaluated on Day 5, when the cleaved embryos were transferred into fresh medium for further 2 days. On Day 7 after IVF, embryo outcome was assessed and all the embryos were vitrified by cryotop in 16.5% ethylene glycol, 16.5% dimethyl sulfoxide (DMSO), and 0.5 M sucrose (De Rosa et al. 2007 Ital. J. Anim. Sci. 6(Suppl 2), 747–750). The resistance to cryopreservation was evaluated by assessing the survival rate, on the basis of morphological criteria, after 24 h culture. Data were analyzed by chi-square test. No differences were found in cleavage rates between the control (81.5%) and the L-carnitine group (78.8%). The blastocyst yields (calculated in relation to the cleaved embryos) were not significantly influenced by the L-carnitine treatment (40.2 and 52.9%, in the control and the L-carnitine groups, respectively). However, buffalo embryos cultured in the presence of L-carnitine showed an increased resistance to cryopreservation, as indicated by the higher survival rates recorded after 24 h culture (78.7 and 96.4%, in the control and the L-carnitine groups, respectively; P < 0.01). In conclusion, these results demonstrated that L-carnitine supplementation of culture medium improves the resistance to cryopreservation of in vitro produced buffalo embryos. We speculate that the increased cryotolerance observed in the presence of L-carnitine may be due to a better utilization of the endogenous lipid stores, resulting in improved embryo quality.

128 CULTURE CONDITIONS AFFECT THE SEX RATIO OF IN VITRO PRODUCED BOVINE EMBRYOS

Most systems for producing bovine embryos in vitro use glucose as an energy source despite putative toxic effects. Glucose has a selective embryotoxicity towards female embryos, due to the higher expression of the X-linked glucose-6-phosphate dehydrogenase gene (Kimura et al. 2005 Mol. Reprod. Dev. 72, 201–207). Recently, the replacement of glucose with citrate and myo-inositol in SOF medium supplemented with 5% bovine serum (BS) increased the percentage of female embryos (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Serum also affects the sex ratio of in vitro-produced (IVP) bovine embryos, favoring the male gender (Gutierrez-Adan et al. 2001 Theriogenology 55, 1117–1126). The aim of this work was to evaluate the effect of glucose replacement with myo-inositol during in vitro culture, in the presence of either BS or BSA, on bovine embryo sex ratio. Abattoir-derived oocytes (n = 1164, over 4 replicates) were matured and fertilized in vitro as previously described (Rubessa et al. 2011). After 20 to 22 h of gametes co-incubation, zygotes were denuded and cultured for 7 days in SOF with: group A) 0.34 mM trisodium citrate + 2.77 mM myo-inositol + 5% BS (n = 287); group B) 0.34 mM tri-sodium citrate + 2.77 mM myo-inositol + 8 mg mL–1 BSA(n = 290); group C) 1.5 mM glucose + 5% BS (n = 302) and group D) 1.5 mM glucose + 8 mg mL–1 BSA (n = 285). Representative samples of blastocysts produced in each group (n = 96, 58, 99, and 70, respectively in groups A, B, C, and D) were sexed by PCR as previously described (Rubessa et al. 2011). Differences among groups in blastocyst yields were analyzed by ANOVA. The percentages of female embryos were analyzed by chi-square test. Blastocyst rates in group C were lower (28.1%) than those recorded in groups A, B, and D (35.9, 41.0 and 36.1%, respectively; P < 0.01). A higher (P < 0.05) percentage of female embryos was observed in group A (61.5%) compared to group C (45.5%), with intermediate values in groups B (51.7%) and D (60.0%). Therefore, the replacement of glucose with citrate and myo-inositol favored the development of female embryos in the presence of BS but was ineffective in the presence of BSA. Furthermore, when glucose was the energy source, a tendency to greater incidence of female embryos was observed when the medium was supplemented with BSA rather than BS (P = 0.06). As a small amount of glucose is present in the BS, we hypothesize an additional glucose-dependent toxic effect on female embryos in group C. However, we cannot rule out that other factors present in the BS may interact with the energy source, playing a role in determining the sex ratio. Furthermore, the shift in sex ratio in favor of males or females embryo can be due to a better development of embryo of one sex, or to the delayed development or degeneration of embryos of the other sex. In conclusion, these results suggest that manipulating the metabolic profile of the embryos during culture may have an impact on both blastocyst production and sex ratio.

Effect of energy source during culture on in vitro embryo development, resistance to cryopreservation and sex ratio

The aim of this work was to evaluate whether minimizing the glucose concentration during culture or replacing the hexose with other energy substrates and/or embryotrophic compounds would affect the in vitro development, the resistance to cryopreservation and the sex ratio of bovine embryos. In vitro matured and fertilized oocytes were randomly assigned to 4 groups for in vitro culture, that differed in the energy substrates included: group A) 1.5 mM glucose, as in standard SOF; group B) 0.15 mM glucose; group C) 0.125 mM G3P, in the presence of 0.15 mM glucose and group D) 0.34 mM citrate, in combination with 2.77 mM myo-inositol. Blastocysts were evaluated on day 7, then vitrified by cryotop in 16.5% DMSO, 16.5% EG and 0.5 M sucrose and warmed in decreasing concentration of sucrose (0.25 to 0.15 M sucrose). The survival rates were assessed after 24 h in vitro culture. Finally, the blastocysts produced were sexed by PCR. An increased blastocyst rate was recorded in groups B, C and D, i.e., when glucose concentration was reduced, compared to group A (28.2, 41.0, 35.7 and 35.8, respectively in groups A, B, C and D; P < 0.01). However, the embryos cultured in group D showed the slowest developmental speed, indicated by the lowest percentage of advanced stage-embryos (expanded and hatched blastocysts) out of the total blastocysts (56.1, 45.8, 56.9 and 31.8 %, respectively in groups A, B, C and D; P < 0.01). Furthermore, survival rates after 24 h culture of vitrified-warmed blastocysts also decreased in group D (73.3, 73.1, 71.4 and 58.4%, respectively in groups A, B, C and D; P < 0.01). Interestingly, in group D a higher percentage of female embryos was obtained compared to group A, with intermediate values in groups B and C (45.6, 53.4, 50.0 and 61.5%, respectively in groups A, B, C and D; P < 0.05). In conclusion, it was demonstrated that the energy substrate during in vitro culture affects both the production and the viability of blastocysts. Furthermore, manipulating the metabolic profile of embryos during in vitro culture may have an impact on sex ratio.

Clinical and Serological Features of Patients with Suspected Lyme Borreliosis

Serology is currently the method of choice for the laboratory diagnosis of Lyme borreliosis, but it must be interpreted with caution. A total of 954 patients with suspected Lyme borreliosis were evaluated on the basis of clinical and serological data. The seroprevalence of Borrelia burgdorferi antibodies was 4.4% (42 of the 954 serum samples). The most frequent clinical manifestation was erythema migrans which occurred in 50% of the seropositive patients, followed by neuroborreliosis (16.6%) and arthritis (11.9%). Carditis was rare. Our findings suggest that for the diagnosis of Lyme borreliosis, serologic tests need to be combined with clinical signs and symptoms.

The influence of gamete co-incubation length on the in vitro fertility and sex ratio of bovine bulls with different penetration speed

The objectives of this work were to evaluate whether the sperm penetration speed is correlated to the in vitro fertility and whether adapting the gamete co-incubation length to the kinetics of the bull improves in vitro fertility and affects the sex ratio. In vitro matured oocytes were co-incubated with spermatozoa from four different bulls (A-D). At various post-insemination (p.i.) times (4, 8, 12, 16 and 20 h), samples of oocytes were fixed and stained with DAPI for nuclei examination, while the remaining ones were transferred into culture to evaluate embryo development. The blastocysts produced were sexed by PCR. Two bulls (A and B) had faster kinetics than the others (C and D), as shown by the higher penetration rates recorded at 4 h p.i. (43%, 30%, 11% and 6%, respectively for bulls A, B, C and D; p<0.01). The differences in the kinetics among bulls did not reflect their in vitro fertility. The incidence of polyspermy was higher for faster penetrating bulls (36%, 24%, 16% and 4%, respectively for bulls A, B, C and D; p<0.01) and at longer co-incubation times (0%, 16%, 19%, 30% and 34%, respectively at 4, 8, 12, 16 and 20 h p.i.; p<0.01). The fertilizing ability of individual bulls may be improved by adapting the co-incubation length to their penetration speed. A sperm-oocyte co-incubation length of 8 h ensured the greatest blastocyst yields for the two faster penetrating bulls. On the contrary, 16 h co-incubation was required to increase (p<0.01) cleavage rate of the two slower bulls. Bulls with a faster kinetics did not alter the embryo sex ratio towards males. The female/male (F/M) ratios recorded were 2.1, 1.4, 1.2, 1.3 and 1.6, respectively at 4, 8, 12, 16 and 20 h p.i.

126 EFFECT OF REDUCING GLUCOSE CONCENTRATION DURING IN VITRO EMBRYO CULTURE IN BUFFALO (BUBALUS BUBALIS)

The current knowledge on metabolism and glucose utilisation of preimplantation bovine and ovine embryos suggest the reduction of glucose concentration during early culture. On the contrary, it has been demonstrated that glucose is absolutely required for in vitro culture of buffalo embryos, as indicated by the poor efficiency recorded in the absence of this substrate during early embryonic development (Monaco et al. 2006 Reprod. Domest. Anim. 41, 332). However, complete removal of glucose from culture medium throughout pre-elongation development is unlikely to benefit the embryo because glucose plays other roles including ribose and NADPH production through the pentose-phosphate pathway. Therefore, the aim of this study was to investigate the effect of reducing glucose concentration up to 0.15 mM (1/10 compared to the standard concentration in SOF) on embryo development in buffalo. In order to evaluate the role of this substrate during development, glucose was reduced at different stages of embryo culture. Cumulus–oocyte complexes (n = 573, over 4 replicates), recovered from slaughtered animals, were matured and fertilized in vitro according to our standard procedures (Gasparrini et al. 2006, Theriogenology, 65, 275–287). On day 1 (Day 0 = IVF), zygotes were cultured in SOF with group A) 1.5 mM glucose (standard concentration in SOF) throughout culture (control); group B) 1.5 mM glucose for early culture (Day 1 to Day 4) and 0.15 mM glucose for late culture (Day 4 to Day 7); group C) 0.15 mM glucose throughout culture; and group D) 0.15 mM glucose for early culture and 1.5 mM glucose for subsequent culture. In vitro culture was carried out at 38.5°C under 5% CO2, 7% O2, and 88% N2. Cleavage rate was evaluated on Day 4, and blastocyst yield, in relation to cleaved embryos, was recorded on Day 7. Differences among groups in blastocyst rate were analysed by chi-square test. The reduction of glucose concentration did not affect cleavage rate (73.7 v. 65.1%, respectively, for Groups A-B and C-D). Nevertheless, blastocyst rates significantly decreased when glucose was reduced throughout culture (Group C: 10.1%; P < 0.01) and to a limited degree during early culture (Group D: 17.2%; P < 0.05) compared with the control (Group A: 38.3%). On the contrary, a decreased glucose concentration during late culture did not reduce embryo development (Group B: 35.18%). This finding indicates that energy requirements of buffalo embryos during IVC are different from those of sheep and cattle, which show a significant rise in glucose uptake just around compaction, i.e. during late culture (Thompson et al. 1991 Reprod. Fertil. Dev. 3, 571–576; Thompson et al. 1996 J. Reprod. Fertil. 106, 299–306). In conclusion, in buffalo, unlike sheep and cattle, glucose is more critical for early embryo development than for post-compaction development, suggesting the importance of developing other strategies for optimizing in vitro embryo production efficiency.

125 EFFECT OF GLYCERALDEHYDE-3-PHOSPHATE DURING BOVINE IN VITRO EMBRYO CULTURE

Most systems for producing mammalian embryos in vitro use glucose as an energy source in the media despite putative toxic effects (Schini and Bavister 1988 Biol. Reprod. 39, 1183–1192; Takahashi and First 1992 Theriogenology 37, 963–978). Currently there is a tendency to identify other suitable energy sources in an attempt to replace glucose from culture media. Glyceraldehyde-3-phosphate (G3P), a glucose-derived high-energy compound, is the end product of the energy-consuming phase of glycolysis that enters the pay-off phase of the pathway characterised by a net gain of energy. The aim of this study was to determine whether G3P is a valid energy source for supporting in vitro embryo development in cattle. Abattoir-derived oocytes (n = 832, over 4 replicates) were matured in vitro in TCM-199 with 15% bovine serum (BS), 0.5 μg mL–1 FSH, 5 μg mL–1 LH, 0.8 mM L-glutamine, and 50 mg mL–1 gentamicin. Mature COC were fertilized in Tyrode’s modified medium, with 30 mg mL–1 heparin, 30 mM penicillamine, 15 mM hypotaurine, 0.15 mM epinephrine, and 1% BS. Both IVM and IVF were carried out at 39°C and 5% CO2 in air. After 20 to 22 h of gamete co-incubation, presumptive zygotes were denuded and cultured in SOF containing either 1.5 mM glucose (control group) or G3P at 3 different concentrations (0.125, 0.5, and 1.5 mM). It is worth specifying that in the 3 G3P-supplemented groups small amounts of glucose were left (0.15 mM) because it is known that a complete removal would affect embryo development by interfering with ribose synthesis through the pentose–phosphate pathway. In vitro culture was carried out at 39°C under humidified air with 5% CO2, 7% O2, and 88% N2 in air for 7 days, when the percentages of tight morulae-blastocysts (TMBL) and superior quality blastocysts (BL) were recorded. Differences in embryo yields among groups were analysed by chi-square test. Supplementation of IVC medium with 1.5 mM G3P reduced (P < 0.01) TMBL (5.0%) and BL (5.0%) rates compared with all other groups, indicating a toxic effect. However, when G3P was added at lower concentrations, no differences in TMBL (37.3 and 26.1, respectively, with 0.125 and 0.5 mM G3P) and in BL rates (35.3 and 25.5%, respectively, with 0.125 and 0.5 mM G3P) were observed compared with the control (32.7% TMBL and 31.4% BL, respectively). Within G3P-treated groups, the higher embryo yields were recorded with 0.125 mM compared with 0.5 mM (P < 0.05) and 1.5 mM (P < 0.01). Interestingly, embryos produced with G3P at the lower concentrations (0.125 and 0.5 mM) seemed to show a faster development compared with the control. In conclusion, these results demonstrated that G3P is a valid energy source for bovine preimplantation embryos and, hence, that G3P supplementation of IVC medium may be a suitable option for reducing glucose concentration in the media. However, further studies are needed to investigate lower concentrations of G3P and to better evaluate embryo viability.

124 CO-CULTURE WITH BOVINE INTACT CUMULUS - OOCYTE COMPLEXES DURING IN VITRO FERTILIZATION OF BUFFALO DENUDED OOCYTES COMPLETELY RESTORES THEIR FERTILIZING AND DEVELOPMENTAL COMPETENCE

Removal of cumulus cells is necessary for several technologies such as vitrification, intracytoplasmic sperm injection, and nuclear transfer. However, it is known that the presence of cumulus cells during IVF of buffalo oocytes is fundamental for fertilization and embryo development (Gasparrini et al. 2007 Anim. Reprod. Sci. 98, 335–342; Nandi et al. 1998 Theriogenology 50, 1251–1262). The aim of this work was to evaluate whether co-culture with intact bovine cumulus–oocyte complexes (COC) during IVF would restore the developmental competence of denuded buffalo oocytes. Due to the scarce availability of buffalo ovaries, the somatic support was provided by bovine cumulus cells. Abattoir-derived COC were matured in vitro according to our standard procedures (Gasparrini et al. 2006, Theriogenology, 65, 275–287) and randomly distributed in 3 fertilization groups: 1) a control group of COC (n = 122), 2) a negative control of denuded oocytes (DO; n = 119), and 3) DO co-cultured with in vitro matured bovine COC (DO+COC; n = 103) in a 1:1 ratio (3 bovine COC + 3 denuded buffalo oocytes/50 μL drop). Fertilization was carried out with frozen–thawed spermatozoa from a tested bull in TALP medium supplemented by 0.2 mM penicillamine, 0.1 mM hypotaurine, and 0.01 mM heparin at 38.5°C under a controlled gas atmosphere of 5% CO2 in humidified air. After fertilization the zygotes were cultured in SOF medium including essential and nonessential amino acids and 8 mg mL–1 BSA, at 38.5°C under humidified 5% CO2, 7% O2, and 88% N2, up to the blastocyst stage. On Day 5 and on Day 7 (Day 0 = IVF) cleavage and blastocyst rates were respectively recorded. Data were analysed by chi-square test. As expected, cleavage and blastocyst rates were lower (P < 0.01) in DO (36.1 and 9.2%, respectively) compared with the control (67.2 and 27.1%, respectively). However, co-culture during IVF (DO+COC) significantly increased (P < 0.01) both parameters compared with DO, giving cleavage (70.9%) and blastocyst (27.2%) rates similar to the control. The results of this study demonstrated that co-culture with bovine intact COC during IVF of buffalo denuded oocytes completely restores their fertilizing capability and blastocyst developmental competence. We conclude that this may be a suitable strategy for preserving the developmental competence of oocytes devolved to technologies, such as oocyte vitrification, that require cumulus removal.