53 VITRIFICATION OF HANDMADE CLONED BUFFALO EMBRYOS USING ETHYLENE GLYCOL AND DIMETHYL SULPHOXIDE AND SUBSEQUENT EFFECT ON CRYOSURVIVAL AND APOPTOSIS

The objective of the present work was to optimize concentration of cryoprotectants ethylene glycol (EG) and dimethyl sulphoxide (DMSO) to facilitate the vitrification of buffalo embryos produced by somatic cell nuclear transfer (SCNT). Cloned embryos were produced according to standardized protocols of our laboratory using handmade cloning (Shah et al. 2008). Three different concentrations of EG and DMSO (7.5, 10 and 15%, having 0.5 M sucrose in TCM-199 containing 20% serum) were selected in combination for vitrification of cloned blastocysts in French ministraws (0.25 mL). The numbers of cloned blastocysts vitrified for each concentration were 51, 51 and 52, respectively. The post-thaw viability was accessed by re-expansion rate of blastocysts after culturing in RVCL media (K-RVCL-50, Cook® Australia, Queensland, Australia) for 18 to 24 h. On the basis of re-expansion rate, there was no significant effect of any selected concentrations (7.5, 10 and 15%) on post-thaw viability (25.33 ± 2.43%, 29.00 ± 2.52% and 30.83 ± 3.01%, respectively; P > 0.05). The effect of vitrification on apoptosis level was checked after 18 to 24 h post-thaw by TUNEL assay and the apoptosis index was calculated by dividing the total number of nuclei with DNA-fragmented positive nuclei of the respective blastocyst. We found that, 7.5%-group embryos resulted with a significantly higher apoptotic index (8.28 ± 0.57) than that of the 10 and 15% groups (5.09 ± 0.46 and 4.28 ± 0.24, respectively; P < 0.05). These results clearly indicate that a lower concentration of cryoprotectants (7.5%) increased the chance of apoptosis in blastocysts that were frozen-thawed. The quantitative expression of apoptosis-related genes (Bax, Bid, Mcl-1 and Bcl-xl) in all 3 treatment groups and fresh control embryos were determined by RT-qPCR. Three replications were performed and the mRNA level of each sample was normalized to that of glyceride-3-phosphate dehydrogenase mRNA level. Results of RT-qPCR were analysed using the 2–ΔΔCT method to compare the relative transcriptional levels of the target genes in each group. The RT-qPCR data revealed that the 7.5% vitrified group embryos possessed high expression of pro-apoptotic genes (Bax and Bid) and lower expression of anti-apoptotic genes (Mcl-1 and Bcl-xl) in comparison to the 10 and 15% groups. However, there was no significant change in gene expression between the 10 or 15% groups in comparison with fresh non-vitrified embryos. Our results conclude that the best choice is to use 10 or 15% EG and DMSO cryoprotectants for in-straw zona-free cloned buffalo embryo vitrification. However, further experiments are needed to enhance survival after vitrification. This work was supported by research grants from the National Agriculture Innovative Project (1(5)/2007-NAIP-2) to S. K. Singla.

Optimization of culture conditions to support long-term self-renewal of buffalo (Bubalus bubalis) embryonic stem cell-like cells

A culture system capable of sustaining self-renewal of buffalo embryonic stem (ES) cell-like cells in an undifferentiated state over a long period of time was developed. Inner cell masses were seeded on KO-DMEM+15% KO-serum replacer on buffalo fetal fibroblast feeder layer. Supplementation of culture medium with 5 ng/mL FGF-2 and 1000 IU/mL mLIF gave the highest (p<0.05) rate of primary colony formation. The ES cell-like cells' colony survival rate and increase in colony size were highest (p<0.05) following supplementation with FGF-2 and LIF compared to other groups examined. FGF-2 supplementation affected the quantitative expression of NANOG, SOX-2, ACTIVIN A, BMP 4, and TGFβ1, but not OCT4 and GREMLIN. Supplementation with SU5402, an FGFR inhibitor (≥20 μM) increased (p<0.05) the percentage of colonies that differentiated. FGFR1-3 and ERK1, K-RAS, E-RAS, and SHP-2, key signaling intermediates of FGF signaling, were detected in ES cell-like cells. Under culture conditions described, three ES cell lines were derived that, to date, have been maintained for 135, 95, and 85 passages for over 27, 19, and 17 months, respectively, whereas under other conditions examined, ES cell-like cells did not survive beyond passage 10. The ES cell-like cells were regularly monitored for expression of pluripotency markers and their potency to form embryoid bodies.

Characterization of POU5F1 (OCT4) gene and its promoter in buffalo ESC-like cells identifies multiple transcription start sites and expression of four pseudogenes

In the present study, we cloned and characterized the buffalo (Bubalus bubalis) OCT4 ortholog expressed in embryonic stem cell (ESC) like cells and its promoter region. The 5'- and 3'-RACE experiments were conducted to analyze the transcription initiation site and regulatory regions. The comparative analysis of buffalo OCT4 promoter with other mammalian orthologs revealed high conservation. Among the regulatory regions highest similarity was observed between buffalo, bovine and sheep. Interestingly, buffalo OCT4 promoter exhibited a 78 bp deletion between two proximal enhancers (PE-1A and PE-1B) when compared to other mammalian orthologs. 5'-RACE revealed four different transcription start sites for OCT4 gene. As far as we know there is no previous report regarding multiple transcription initiation sites for OCT4 gene in any species. In addition, we identified expression of four pseudogenes in buffalo ESC-like cells. Among the multiple transcripts characterized, we found four cDNA clones (1083 bp) derived from ESC-like cells sharing 96.9-99.3% sequence homology with the parent gene and having the capacity of encoding 139, 206, 206 and 324 amino acid long truncated proteins. Multiple pseudogenes have been proposed for OCT4 which might contribute to the false detection of this gene during expression studies. However, only few of them were reported to be transcribed and none were reported to be translated in stem cells. Western blot analysis of OCT4 protein using ESC-like cells revealed multiple bands, indicating that some of the hypothetical pseudogenes are being translated. These novel pseudogenes or their protein products may have some important regulatory functions.

Effects of FSH and LH on steroid production by buffalo (Bubalus bubalis) granulosa cells cultured in vitro under serum-free conditions

The objective of this study was to examine the effects of FSH and LH on oestradiol-17β and progesterone production by buffalo granulosa cells cultured under serum-free conditions. Granulosa cells (3 × 10(5) ) from small (≤ 5 mm diameter) follicles were cultured for up to 4 days in 48-well plates coated with 3.3 μg/cm(2) fibronectin in Dulbecco's modified Eagle's medium (DMEM) : nutrient mixture F-12 Ham (1 : 1 ratio) supplemented with 10(-7) m androstenedione, 5 μg/ml human apo-transferrin and 0.1% bovine serum albumin, in the presence or absence of FSH or LH (0, 1, 2, 4, 8, 16, 32 or 64 ng/ml each). Basal oestradiol-17β production by granulosa cells from small follicles reduced (p < 0.01) from days 1 to 2 of culture and became undetectable by day 3 and basal progesterone production increased (p < 0.05) from day 1 through day 4 of the culture. Although there was no effect of FSH on day 1 of the culture, FSH at 2, 4, 8 and 16 ng/ml increased (p < 0.05) oestradiol-17β production by granulosa cells from small follicles on day 2. Progesterone secretion was increased (p < 0.05) by all doses of FSH on all days of culture. All doses of LH had no effect on oestradiol-17β or progesterone production by granulosa cells from small follicles on any day of the culture. The results of this study demonstrate a serum-free culture system for buffalo granulosa cells and stimulatory effect of FSH but not LH on steroid hormone production by buffalo granulosa cells under these conditions.

Assessment of DNA damage during in vitro development of buffalo (Bubalus bubalis) embryos: effect of cysteamine

Comet assay was used in the present study to examine DNA damage to buffalo oocytes and embryos during in vitro culture. Embryos were produced in vitro from oocytes obtained from slaughterhouse ovaries in presence of cysteamine (IVM and IVC media supplemented with 50 and 100 μM, respectively) or in its absence (controls). Compared to controls, cysteamine supplementation increased (p < 0.01) cleavage rate and proportion of oocytes that developed to 8- to 16-cell stage. The incidence of DNA damage was lower (p < 0.01) in cysteamine group than that in controls at 8- to 16- (19.3 ± 4.24 vs 72.0 ± 5.22%) but not in 2-cell stage embryos (11.7 ± 5.63 vs 20.8 ± 5.49%) or in mature oocytes (5.3 ± 3.43 vs 10.3 ± 4.73%). The tail length, which indicates magnitude of DNA damage, was shorter (p < 0.01) in cysteamine group than in controls in mature oocytes (25.5 ± 0.5 vs 36.0 ± 0.71 pixels) and 8- to 16-cell stage (49.2 ± 1.64 vs 152.7 ± 1.28 pixels) but not in 2-cell stage embryos (36.3 ± 1.54 vs 36.4 ± 0.75 pixels). Also, exposure of oocytes/embryos to UV radiation or H2O2 caused extensive DNA damage. In conclusion, these results suggest that oocytes/embryos suffer from DNA damage during progress of in vitro culture, which can be partly ameliorated by cysteamine supplementation of culture media.

Effect of cytoplasmic volume on developmental competence of buffalo (Bubalus bubalis) embryos produced through hand-made cloning

This study examined the effects of cytoplasmic volume on the developmental competence of hand-made cloned buffalo embryos. Two different cell types, that is, buffalo fetal fibroblast (BFF) and buffalo embryonic stem (ES) cell-like cells were taken as donor cell and fused with one, two, or three demicytoplasts to generate embryos with decreased, normal (control), and increased cytoplasmic volume. Using BFF as a nuclear donor, the cleavage rate was similar in all the groups (p > 0.05), but the blastocysts rate was significantly lower (p < 0.05) for embryos generated with decreased cytoplasmic volume. Using ES cell-like cells, the cleavage and blastocyst rate with increased cytoplasmic volume was significantly higher (p < 0.05) compared that with reduced cytoplasmic volume. Blastocysts produced from embryos having increased cytoplasmic volume had significantly higher (p < 0.05) cell number than normal (control) embryos in both BFF and ES cell-like cells groups. Pregnancies were established in all the groups except for the embryos reconstructed with decreased cytoplasmic volume. The pregnancy rate was almost double for embryos reconstructed using increased cytoplasmic volume compared to that with the controls. Most of the pregnancies aborted in the first trimester and one live calf was delivered through Caesarean, which died 4 h after birth.

Production of cloned and transgenic embryos using buffalo (Bubalus bubalis) embryonic stem cell-like cells isolated from in vitro fertilized and cloned blastocysts

Here, we report the isolation and characterization of embryonic stem (ES) cell-like cells from cloned blastocysts, generated using fibroblasts derived from an adult buffalo (BAF). These nuclear transfer embryonic stem cell-like cells (NT-ES) grew in well-defined and dome-shaped colonies. The expression pattern of pluripotency marker genes was similar in both NT-ES and in vitro fertilization (IVF) embryo-derived embryonic stem cell-like cells (F-ES). Upon spontaneous differentiation via embryoid body formation, cells of different morphology were observed, among which predominant were endodermal-like and epithelial-like cell types. The ES cell-like cells could be passaged only mechanically and did not form colonies when plated as single cell suspension at different concentrations. When F-ES cell-like, NT-ES cell-like, and BAF cells of same genotype were used for hand-made cloning (HMC), no significant difference (p > 0.05) was observed in cleavage and blastocyst rate. Following transfer of HMC embryos to synchronized recipients, pregnancies were established only with F-ES cell-like and BAF cell-derived embryos, and one live calf was born from F-ES cell-like cells. Further, when transfected NT-ES cell-like cells and BAF were used for HMC, no significant difference (p > 0.05) was observed between cleavage and blastocyst rate. In conclusion, here we report for the first time the derivation of ES cell-like cells from an adult buffalo, and its genetic modification. We also report the birth of a live cloned calf from buffalo ES cell-like cells.

Derivation of buffalo embryonic stem-like cells from in vitro-produced blastocysts on homologous and heterologous feeder cells

PURPOSE

The aim of the present study is to compare the ability of homologous and heterologous embryonic fibroblast feeder layers to support isolation and proliferation of buffalo ES-like cells generated from hatched and expanded blastocysts produced by in vitro fertilization and characterization of derived cells through expression of pluripotent markers.

METHODS

Embryonic stem cells were derived from hatched and expanded blastocysts through intact blastocyst culture and enzymatic method respectively and compared for proliferation rate on homologous (buffalo) and heterologous feeder layers (goat and sheep).

RESULTS

A total of 69 hatched and 83 expanded blastocysts were used for isolation of inner cell masses which were seeded on buffalo, goat and sheep embryonic feeder layers. Following seeding, attachment rate, primary colony formation rate and survival to maximum number of passages were observed to be higher on homologous feeder layers.

CONCLUSIONS

Upon comparison of different feeder layer cells for derivation and maintenance of buffalo ES-like cells from hatched and expanded blastocysts, buffalo embryonic fibroblast cells were able to provide a better environment for maintaining pluripotency in culture conditions.

Buffalo (Bubalus bubalis) embryonic stem cell-like cells and preimplantation embryos exhibit comparable expression of pluripotency-related antigens

In this study, inner cell mass (ICM) cells were isolated from in vitro produced buffalo blastocysts and were cultured on mitomycin-C treated buffalo foetal fibroblast feeder layer for producing embryonic stem (ES) cells. Among different sources (hatched vs expanded blastocysts) or methods (enzymatic vs mechanical), mechanical isolation of ICM from hatched blastocysts resulted in the highest primary colony formation rate and the maximum passage number up to which ES cells survived. Putative ES cells expressed alkaline phosphatase and exhibited a normal karyotype up to passage 7. Putative ES cells and embryos at 2- to 4-cell, 8- to 16-cell, morula and blastocyst stages strongly expressed stage-specific embryonic antigen (SSEA)-4 but lacked expressions of SSEA-1 and SSEA-3. Putative ES cells also expressed tumour rejection antigen (TRA)-1-60, TRA-1-81 and Oct4. Whereas in all early embryonic stages, TRA-1-60 was observed only in the periplasmic space, and TRA-1-81 expression was observed as small spots at a few places inside the embryos, both these markers were expressed by ICM. Oct4 expression, which was observed at all the embryonic stages and also in the trophectoderm, was the strongest in the ICM. Buffalo putative ES cells possess a unique pluripotency-related surface antigen phenotype, which resembles that of the ICM.

135 EXPRESSION OF APOPTOSIS-RELATED GENES IN BUFFALO (BUBALUS BUBALIS) EMBRYOS PRODUCED THROUGH IN VITRO FERTILIZATION AND PARTHENOGENETIC ACTIVATION

Apoptosis, a highly conserved evolutionary mechanism that allows an organism to tightly control cell numbers, tissue size, and protect itself from dangerous cells and unfavourable environments that threaten homeostasis, is generally directed by specific genes involved in the regulation of a series of pro-apoptotic (BAX) and anti-apoptotic (BCL-XL) proteins that are expressed during early development. All mammalian species show the highest level of spontaneous apoptotic processes at the blastocyst stage. These proteins prevent apoptosis by maintaining the cell survival by interfering with the release of cytochrome-C from mitochondria. In this study, immature oocytes were obtained from buffalo slaughterhouse ovaries and were subjected to in vitro maturation (IVM) in TCM-199 + 10% FBS + 5 μg mL–1 porcine FSH for 24 h in a CO2 incubator (5% CO2, 90 to 95% relative humidity) at 38.5°C. The mature oocytes were used for IVF, and the cleaved embryos were cultured for 8 days in culture medium (CR2 medium containing 0.6% BSA and 10% FBS) for production of embryos at different stages. The parthenotes were produced with exposure of 7% ethanol, 6-dimethyl aminopurine and cultured for 8 days in culture medium. The total RNA was isolated from oocytes and embryos and transcribed using Cell-to-cDNA-II (Ambion, Austin, TX, USA), according to manufacturer protocol. The PCR cycle included heating to 94°C for 5 min, followed by 35 cycles of 94°C for 30 s, 60 (BAX) and 62°C (BCL) for 30 s, and 72°C for 45 s with a final extension at 72°C for 10 min. The amplified product of both genes were separated on agarose gel and densitometry data for band intensities were generated using AlphaDigiDocTM AD-1201 software under a WindowsTM environment and data analysed with the help of SYSTAT software. Relative abundance of BCL-XL transcripts in immature, mature oocytes and embryos produced through IVF (i.e. 2-cell, 4-cell, 8- to 16-cell, morula, and blastocyst stage) were 25.33 ± 0.90, 12.67 ± 1.20, 37.67 ± 0.90, 30.67 ± 0.30, 23.67 ± 0.90, 18.33 ± 0.90, and 27.00 ± 1.20, respectively, whereas in parthenogenesis these values were 23.67 ± 0.88, 13.67 ± 1.20, 23.67 ± 1.20, 22.34 ± 0.88, 24.34 ± 0.88, 33.67 ± 0.88, and 45.34 ± 1.20, respectively. Relative abundance of BAX transcripts by IVF were 23.0 ± 0.60, 0.33 ± 0.10, 4.00 ± 0.60, 5.00 ± 0.60, 0.37 ± 0.06, 13.0 ± 0.66, and 56.7 ± 0.90; and by parthenonenesis were 22.3 ± 0.90, 0.13 ± 0.03, 13.67 ± 0.90, 14.0 ± 0.60, 15.33 ± 0.90, 64.67 ± 2.20, and 55.0 ± 2.10, respectively. In conclusion, the expression pattern of the apoptosis-related genes revealed that the incidence of apoptosis was significantly higher in IVF and parthenogenetically produced buffalo embryos at stages such as immature oocytes, morula, and blastocyst than the early cleavage stage embryos.

59 SYNCHRONIZATION OF CELL CYCLE STAGE OF BUFFALO (BUBALUS BUBALIS) FETAL FIBROBLAST CELLS BY DIFFERENT TREATMENTS

Cell cycle stage of donor cells significantly influences the cloning efficiency during SCNT. Donor cells in G1/G0 stage have better capability to undergo nuclear reprogramming following transfer to an unfertilized oocyte. The lack of availability of cells synchronized at G1/G0 stage is one of the major factors limiting cloning efficiency in buffalo. The aim of this study was to compare the efficacy of various methods for cell cycle synchronization of buffalo fetal fibroblast cells for SCNT. Cells isolated from fetus, 2 to 3 months old, were cultured in DMEM + 10% FBS. The primary culture was sub-cultured 8 to 10 times. For cell cycle synchronization, the cells were cultured to 1) 60 to 70% confluence (controls), 2) 60 to 70% confluence followed by serum starvation (DMEM + 0.5% FBS) for 24 h (serum starved), 3), full confluence followed by culture for additional 3 to 5 days (full confluent), 4) full confluence followed by serum starvation (DMEM + 0.5% FBS) for 24 h (full confluent+serum starved) and 5) 60 to 70% confluence followed by treatment with roscovitine (10, 20, or 30 μM) for 24 h. The synchronization efficiency was examined by propidium iodide staining followed by analysis of DNA content using flow cytometry and the data were analysed by 1-way ANOVA followed by Fisher’s l.s.d. test after arcsine transformation. The percentage of cells in G0/G1 phase of cell cycle was significantly higher (P < 0.05) in the full confluent+serum starved and roscovitine treated (20 or 30 μM) groups than that in the full confluent group and that treated with 10 μM roscovitine which, in turn, was higher (P < 0.05) than that in the serum starved and control groups. These results suggest that buffalo fetal fibroblast cells can be synchronized by roscovitine treatment or by serum starvation of fully confluent cell cultures to obtain a high proportion of cells in G0/G1 stage for SCNT. Table 1.Buffalo skin fibroblast cells at various stages following different treatments for cell cycle synchronization Supported by grant No. 1(5)/2007-NAIP from ICAR, India.

309 DEVELOPMENT OF A CULTURE SYSTEM CAPABLE OF LONG-TERM MAINTENANCE OF BUFFALO (BUBALUS BUBALIS) EMBRYONIC STEM CELLS

The present study was aimed at developing a system for long-term culture of buffalo embryonic stem (ES) cells, which, to our knowledge, have not been maintained beyond passage 10 in reports available to date, primarily because of lack of information on their specific requirements during in vitro culture. Inner cell mass (n = 181) cells, mechanically isolated from in vitro produced day 8 blastocysts, were cultured on mitomycin-C-treated buffalo fetal fibroblast feeder layers in stem cell medium (SCM), which consisted of Knockout-DMEM® + 15% Knockout serum replacer® + 1% minimal essential medium nonessential amino acids + 50 μg mL–1 of gentamicin, supplemented with 1000 IU mL–1 of leukemia inhibitory factor (LIF) and fibroblast growth factor-2 (FGF-2) at different concentrations. The medium was changed every 24 h. The primary colony formation rate, which was similar for 5, 10, 20, and 40 ng mL–1 of FGF-2 (63.7 ± 5.2, 65.7 ± 6.5, 57.0 ± 10.5, and 62.8 ± 13.30, respectively), was significantly higher (P ≤ 0.05) than that of controls (22.4 ± 5.5). In Experiment 2, ES-cell-like cell colonies at passages 6 through 7 (n = 441) were cultured for 5 to 6 days to examine the effects of media supplements. The percentage of colonies that survived was significantly higher (P ≤ 0.05) when these were cultured in SCM+LIF+5 ng mL–1 of FGF-2 (93.1 ± 1.8) than when these were cultured in SCM alone (73.5 ± 9.0) or in SCM supplemented with FGF-2 (88.8 ± 5.4) or LIF (85.8 ± 3.7). Following examination of the colony size at 0 and 120 h of culture, the increase in colony size was found to be nearly 4- (P ≤ 0.01) and 2-fold higher (P ≤ 0.05) with SCM+LIF+5 ng mL–1 of FGF-2 (41.9 ± 3.4) and SCM+FGF-2 (21.0 ± 3.0), respectively, than with SCM alone (10.8 ± 2.6) or with SCM+LIF (9.3 ± 3.3). The ES cell colonies cultured in the presence of FGF-2 were compact and had defined edges, whereas those cultured in its absence were less compact, irregularly shaped, and had less defined edges. To confirm the role of FGF-2 in maintenance of buffalo ES cells, the cell colonies cultured in the presence of 5 ng mL–1 of FGF-2 (n = 487) were exposed to different concentrations (10, 20, or 30 μM) of SU5402, a FGF-2 receptor inhibitor, for 5 to 6 days. The percentage of cell colonies that were found to have differentiated was significantly higher (P ≤ 0.05) when these had been cultured in the presence of 30 (78.6 ± 4.2) or 20 μM (47.9 ± 1.0) than when these were cultured with 10 (24.5 ± 5.1) or 0 μM (28.6 ± 2.3) of SU5402. Following culture in SCM+LIF+FGF-2, buffalo ES cells, in which the expression of pluripotency markers such as OCT-4, NANOG, and SOX-2 was regularly confirmed, have been maintained for more than 80 passages for over an year’s time to date, indicating that a combination of LIF and FGF-2 is beneficial for the maintenance of buffalo ES cells. Supported by NAIP grant No. C4/C-2067 from ICAR, India.

224 LOCALIZATION OF NITRIC OXIDE SYNTHASE ACTIVITY IN BUFFALO (BUBALUS BUBALIS) OOCYTES AND EMBRYOS

Ovarian nitric oxide (NO) and that produced within the oocytes and embryos have been reported to play important roles in oocyte meiotic maturation and embryo development. Production of NO is catalyzed by NO synthase (NOS), which exists in 3 isoforms, the constitutive endothelial (eNOS) and neuronal (nNOS) isoforms and the inducible (iNOS) isoform. We have previously shown that low concentrations of NO stimulate and high concentrations inhibit embryo development, and that endogenous NO produced by iNOS is necessary for optimal embryo development in the buffalo. The present study was aimed at localizing different isoforms of NOS and examining their relative mRNA abundance in buffalo oocytes and embryos. Oocytes from slaughterhouse ovaries were subjected to in vitro maturation in 100-μL droplets (10 to 15 oocytes/droplet) of in vitro maturation medium (TCM-199 + 10% FBS + 5 μg mL–1 of pFSH + 1 μg mL–1 of oestradiol-17β + 0.81 mM sodium pyruvate + 10% buffalo follicular fluid + 50 μg mL–1 of gentamicin) for 24 h in a CO2 incubator (5% CO2 in air) at 38.5°C. In vitro fertilization was carried out by incubating in vitro-matured oocytes with 2 to 4 million spermatozoa mL–1 for 18 h. The presumed zygotes were cultured on original beds of cumulus cells in in vitro culture medium (mCR2aa + 0.6% BSA + 10% FBS) for up to 8 days post-insemination. Immature and in vitro-matured oocytes and embryos at the 2-cell, 4-cell, 8- to 16-cell, morula, and blastocyst stages were examined for the presence of NOS isoforms by indirect immunofluorescence staining using epifluorescence microscopy and RT-PCR. Each experiment was repeated in triplicate, and data were analysed using one-way ANOVA, after arcsine transformation of percentage values. Expression of all 3 NOS isoforms was detected inside the cytoplasm, in all the stages of oocytes and embryos examined, by both immunofluorescence and RT-PCR. Abundance of the iNOS transcript was significantly higher (P ≤ 0.01) in the morula and blastocyst stages compared with that in immature and in vitro-matured oocytes and in embryos at the 2-cell, 4-cell, and 8- to 16-cell stages, indicating that its expression was up-regulated at the 8- to 16-cell stage. The expression of eNOS was significantly higher (P ≤ 0.05) in the immature and mature oocytes and in 8- to 16-cell stage embryos, morulae, and blastocysts than in the early-cleavage embryos at the 2- and 4-cell stages, indicating that it was down-regulated after fertilization and was up-regulated again at the 8- to 16-cell stage. Abundance of the nNOS transcript was not significantly different among all the stages of oocytes and embryos examined. These results demonstrate that different NOS isoforms are expressed in a dynamic manner during embryonic development in the buffalo. The role of an increase in expression of iNOS and eNOS at the 8- to 16-cell stage, at which a developmental block occurs in this species, needs to be examined.

60 EFFECT OF CYTOPLASMIC VOLUME ON DEVELOPMENTAL COMPETENCE OF HAND-GUIDED CLONED BUFFALO (BUBALUS BUBALIS) EMBRYOS

Despite recent successes in the birth of buffalo calves cloned through SCNT or hand-guided cloning (HGC), the cloning efficiency is very low in this species because of lack of information on factors that influence it. The goal of this study was to examine the effects of cytoplasmic volume on the developmental competence of cloned buffalo embryos produced by HGC. In vitro matured oocytes were stripped of their cumulus investment and zona pellucida using hyaluronidase and pronase, respectively. Protrusion cone-guided bisection of zona-free oocytes was performed to remove the nucleus. For reconstructing control HGC embryos, 2 enucleated oocytes (demi-cytoplasts) were fused with a single somatic cell. For reconstruction of embryos with lower or higher cytoplasmic volume, 1 or 3 demi-cytoplasts were fused, respectively, with the donor somatic cell. 2 different cell types, i.e. buffalo fetal fibroblasts (BFF) between passage 10 and 15 and buffalo embryonic stem cell (ESC)-like cells between passage 22 and 25 were used as nuclear donors in 2 different experiments. Data were analysed by 1-way ANOVA after arcsine transformation of percentage values. For BFF, the blastocyst rate for doublet and triplet embryos were significantly higher (P ≤ 0.01) than that for singlet embryos despite the cleavage rate for the 3 groups being similar. For the ESC-like cells, the cleavage and the blastocyst rate were significantly lower (P ≤ 0.01) for the singlet than that for the doublet embryos. The pregnancies were established only in doublet and triplet embryo groups using BFF cells and in the doublet embryo group using ESC-like cells. These results indicate that increasing the cytoplasmic volume could be helpful in improving cloning efficiency in terms of blastocyst production rate in buffaloes. Table 1.Effect of cytoplasmic volume on the developmental competence of cloned buffalo embryos This work was funded by NAIP grant C 2-1-(5)/2007 to SKS.

311 EXPRESSION OF PLURIPOTENT MARKER NUCLEOSTEMIN IN BUFFALO (BUBALUS BUBALIS) EMBRYOS AND EMBRYONIC STEM CELLS GENERATED THROUGH PARTHENOGENETIC ACTIVATION

Nucleostemin is a newly found putative GTPase protein that binds to P53 and exists mainly in the nucleoli and at a very low level in nucleoplasm of undifferentiated embryonic stem cells (ESC) and myeloid stem cells but is not expressed in committed and terminally differentiated cells. Embryonic stem cells are pluripotent cells derived from the inner cell mass (ICM) of blastocysts. The ICM and ESC express a number of transcription factors, and their expression is used as a pluripotency marker in the ESC of many species. The present study was undertaken to identify expression of the nucleostemin gene in different developmental stages of buffalo embryos and cultured ESC. Parthenogenetic activation is a process by which an oocyte can be developed up to blastocyst without fertilization. The parthenotes were produced by following protocol. Briefly, immature oocytes were aspirated from slaughterhouse buffalo ovaries and subjected to in vitro maturation for 24 h in a CO2 incubator (5% O2, 5% CO2, 90–95% relative humidity) at 38.5°C. After 24 h of in vitro maturation, oocytes were activated by exposure to 7% ethanol for 7 min, followed by incubation with 2 mM 6-dimethyl aminopurine in CR2 medium for 3.5 h, and they were then subjected to in vitro culture. The activated embryos were cultured for 8 days in CR2 medium containing 0.6% BSA and 10% FBS to obtain different stages (immature and mature oocytes 2-, 4-,8–16-cell, morula, and blastocyst) of embryos. A total of 23 blastocysts were produced parthenogenetically, of which 5 blastocysts were used for nucleostemin expression and the rest were used for ICM isolation. The isolated ICM were subsequently cultured on mitomycin-C (10 μg mL–1) treated buffalo fetal fibroblast feeder layer in DMEM medium supplemented with 20% fetal bovine serum, 1 000 IU mL–1 of mouse leukemia inhibitory factor, 1% nonessential amino acids, 2 mM L-glutamine, and 50 μg mL–1 gentamycin. These ESC were cultured up to 5 passages. The 5 embryos of different developmental stages and a clump of ESC were used for nucleostemin expression. The total RNA was isolated and transcribed using Cell-to-cDNA-II (Ambion, Austin, TX, USA) according to manufacturer protocol. To amplify the nucleostemin gene, the PCR cycle was carried out and included heating to 94°C for 5 min, followed by 35 cycles at 94°C for 30 s, 60°C for 30 s, and 72°C for 40 s. The expressions of nucleostemin transcript were observed in all the developmental stages including immature and mature oocytes. The transcript was highly expressed in the 2-cell stage, blastocysts, and ESC, but immature oocytes and 8–16-cell stage showed lower expression. The experiment was repeated, and the same result was found. To our knowledge this is the first report in buffalo. It is concluded that the transcript was expressed in all the early stages of parthenogenetically derived buffalo embryos from immature oocytes to blastocysts and continued to be expressed in ESC. This work was funded by NAIP, C-420678075, India.

310 EFFECT OF TGF-β1 ON THE SELF-RENEWAL OF BUFFALO (BUBALUS BUBALIS) EMBRYONIC STEM CELLS

Substantial species differences exist in the type of signalling pathways that govern self-renewal of embryonic stem (ES) cells in a pluripotent state. Members of TGF-βsuper-family, which includes more than 30 proteins in mammals, play an important role in self-renewal of these cells in several species. Production of ES cells from buffalo, a very important farm animal in many developing countries, could have a big influence on their genetic modification through transgenesis and cloning. The aim of this study was to examine the role of TGF-β1 in self-renewal of buffalo ES cells, because no information is available on any signalling pathway in ES cells of this species. Buffalo ES cells derived from in vitro produced embryos between passage 41 and 64 that had been characterised using transcription-based markers OCT-4, NANOG, SOX-2, FOXD-3, REX-1, STAT, and NUCLEOSTAMIN and surface markers SSEA-1, SSEA-3, SSEA-4, TRA-1–60, and TRA-1–81 were cultured on buffalo fetal fibroblast feeder layer in ES cell culture medium (Knockout-DMEM + 15% Knockout Serum Replacer + 5 ng mL–1 of fibroblast growth factor-2 + 1000 IU mL–1 of murine leukemia inhibitory factor) and TGF-β1 (0, 0.1, 1.0, or 10 ng mL–1) or its inhibitor SB431542 (0, 10, 25, or 50 μM). The medium containing TGF-β1 or SB431542 at respective concentrations was changed every 24 h. The percentage of colonies that appeared morphologically normal after 144 h of culture and the colony size at 24, 72, and 144 h of culture were recorded. The percentage of ES cell colonies found to be morphologically normal (rounded or dome shaped, compact, with defined edges, and with no apparent signs of cell death) was significantly higher (P ≤ 0.05) with 1.0 ng mL–1 of TGF-β1 than that with 0 (control), 0.1, or 10 ng mL–1 of TGF-β1. Although the percent increase in ES cell colony size was significantly higher (P ≤ 0.05) with 1.0 ng mL–1 of TGF-β1 than that of controls or with other concentrations of TGF-β1 at 72 h, the increase in colony size was not significantly different among the 4 groups at 144 h of culture. The percentage of ES cell colonies found to be morphologically normal was not significantly different for 0 (control), 10, or 25 μM of SB-431542 but decreased significantly (P ≤ 0.05) with 50 μM of SB-431542. During the 144-h period of culture, the percent increase in colony size was significantly lower (P ≤ 0.05) with 10 μM SB-431542 than that in the controls, whereas with 25 or 50 μM SB-431542, the colony size decreased (P ≤ 0.05) instead of increasing. Buffalo fetal fibroblast feeder layers expressed TGF-β1 strongly at passage-3, -5, and -7, as examined by RT-PCR. These results suggest that although TGF-β signalling appears to be active in buffalo ES cells, TGF-β1 supplementation of culture medium does not improve the self-renewal of buffalo ES cells, at least in the presence of fibroblast growth factor-2 and leukemia inhibitory factor. This work was supported by NAIP grant No. C4/C-2067 from ICAR, India.

A new highly penetrant form of obesity due to deletions on chromosome 16p11.2

Obesity has become a major worldwide challenge to public health, owing to an interaction between the Western 'obesogenic' environment and a strong genetic contribution. Recent extensive genome-wide association studies (GWASs) have identified numerous single nucleotide polymorphisms associated with obesity, but these loci together account for only a small fraction of the known heritable component. Thus, the 'common disease, common variant' hypothesis is increasingly coming under challenge. Here we report a highly penetrant form of obesity, initially observed in 31 subjects who were heterozygous for deletions of at least 593 kilobases at 16p11.2 and whose ascertainment included cognitive deficits. Nineteen similar deletions were identified from GWAS data in 16,053 individuals from eight European cohorts. These deletions were absent from healthy non-obese controls and accounted for 0.7% of our morbid obesity cases (body mass index (BMI) >or= 40 kg m(-2) or BMI standard deviation score >or= 4; P = 6.4 x 10(-8), odds ratio 43.0), demonstrating the potential importance in common disease of rare variants with strong effects. This highlights a promising strategy for identifying missing heritability in obesity and other complex traits: cohorts with extreme phenotypes are likely to be enriched for rare variants, thereby improving power for their discovery. Subsequent analysis of the loci so identified may well reveal additional rare variants that further contribute to the missing heritability, as recently reported for SIM1 (ref. 3). The most productive approach may therefore be to combine the 'power of the extreme' in small, well-phenotyped cohorts, with targeted follow-up in case-control and population cohorts.

Effect of type of cryoprotectant on morphology and developmental competence of in vitro-matured buffalo (Bubalus bubalis) oocytes subjected to slow freezing or vitrification

The present study examined the effects of different cryoprotectants on morphology and developmental competence of in vitro-matured buffalo oocytes after slow freezing or vitrification. After slow freezing in dimethyl sulfoxide (DMSO), ethylene glycol (EG) or 1,2-propanediol (PROH), at 1.0 or 1.5 m each, the proportion of morphologically normal oocytes recovered was significantly higher (P < 0.05) with 1.5 than 1.0 m for all cryoprotectants and was highest (P < 0.05) for 1.5 m DMSO. Following vitrification, the percentage of morphologically normal oocytes recovered was lower (P < 0.01) for 40% EG than for 40% DMSO, 20% EG + 20% DMSO or 20% EG + 20% PROH. The most common damage, irrespective of the cryopreservation method, was loss of cumulus mass. The cleavage rate and the proportion of vitrified-warmed oocytes that developed to morulae/blastocysts were significantly higher (P < 0.01) for 20% EG + 20% DMSO than for the other groups. A higher proportion of oocytes developed to morulae (11.5% v. 4.3%) or blastocysts (5.4% v. 0.6%) after vitrification in 20% EG + 20% DMSO than after slow freezing in 1.5 m DMSO. In conclusion, vitrification was more effective than slow freezing for the cryopreservation of in vitro-matured buffalo oocytes.

Cysteamine supplementation of in vitro maturation medium, in vitro culture medium or both media promotes in vitro development of buffalo (Bubalus bubalis) embryos

The effects of supplementation of in vitro maturation (IVM) or in vitro culture (IVC) or both IVM and IVC media with cysteamine on the yield, hatching rate (HR) and total cell number (TCN) of buffalo blastocysts were examined. Oocytes obtained from slaughterhouse buffalo ovaries were subjected to IVM and IVF. The IVM or IVC media were supplemented with 0, 50, 100 or 200 microm cysteamine. Supplementation of IVM medium with 50 microm cysteamine increased (P < 0.01) the cleavage rate and blastocyst yield without affecting the HR and TCN whereas a higher concentration of 200 microm significantly (P < 0.05) reduced the blastocyst yield but not TCN. Similar increases in blastocyst yield, without any effect on HR and TCN were observed after supplementation of the IVC medium with 100 (P < 0.01) or 50 microm (P < 0.05) cysteamine, whereas 200 microm cysteamine was ineffective. Supplementation of both IVM medium with 50 microm cysteamine and of IVC medium with 100 microm cysteamine increased the yield of blastocysts and hatched blastocyst by over 100% (P < 0.01) compared with the controls without any adverse effects on HR or TCN. The results of the present study suggest that supplementation of both IVM and IVC media improves the yield of blastocysts without compromising their health.

Effect of slow freezing on morphology and developmental competence of buffalo (Bubalus bubalis) immature oocytes

The present study was conducted to evaluate the effects of three cryoprotectants, dimethyl sulphoxide (DMSO), ethylene glycol (EG) and 1,2-propanediol (PROH), each used at two concentrations (1.0 and 1.5 M) on the morphology, maturation rate and developmental capacity of usable quality immature buffalo oocytes subjected to slow freezing. The addition of the cryoprotectant before freezing and its dilution after thawing were carried out in a two- (for 1.0 M) or three-step manner (for 1.5 M). The incidence of damage was found to be significantly higher (P<0.05) with the lower concentration of 1.0 M, compared to that with 1.5 M for all the three cryoprotectants examined. The proportion of immature oocytes recovered in a morphologically normal state was significantly higher (P<0.05) for DMSO than those for EG or PROH at both 1.0 and 1.5 M concentrations. Among the six combinations evaluated, that of DMSO at 1.5 M concentration was found to be superior to others. Irrespective of the type or concentration of the cryoprotectant, partial or complete loss of the cumulus mass was the most prevalent damage. Following in vitro maturation, the nuclear maturation rate was significantly higher (P<0.05) for DMSO than those for EG or PROH at both 1.0 and 1.5 M concentrations. When the in vitro matured oocytes were subjected to in vitro fertilization after slow freezing, using 1.5 M DMSO as cryoprotectant, 4.5% and 0.6% of them were able to develop to morulae and blastocysts, respectively, on Day 9 post insemination, compared to 19.2% and 10.6%, respectively, for the controls. In conclusion, DMSO was more effective than EG or PROH for the slow freezing of immature buffalo oocytes and blastocysts could be produced from immature buffalo oocytes subjected to slow freezing in 1.5 M DMSO.

166 EXPRESSION OF PLURIPOTENCY-DETERMINING FACTORS IN IN VITRO-PRODUCED BUFFALO EMBRYOS

Embryonic stem cells (ESCs) are derived from the inner cell mass (ICM) of blastocysts. These are pluripotent cells that retain the ability to differentiate into all cell types. Various cell surface antigens, the expressions of which have been widely used as markers to monitor the pluripotency of ESCs, include Oct-4, stage-specific embryonic antigens (SSEAs) such as SSEA-1, SSEA-3, and SSEA-4, and tumor rejection antigens (TRAs) such as TRA-1-60 and TRA-1-81. In this study, the cell surface expression patterns of these markers were examined in in vitro-produced buffalo embryos at the 2-, 4-, 8- to 16-cell, morula, and blastocyst stages using immunofluorescence microscopy. Oocytes obtained from slaughterhouse buffalo ovaries were subjected to IVM and IVF, following which the cleaved embryos were cultured for 9 days for production of embryos at different stages (n = 246). The embryos were fixed in 4% paraformaldehyde in Dulbecco's phosphate-buffered saline (DPBS) for 30 min, permeabilized by treatment with 0.1% Triton X-100 in DPBS for 30 min, and incubated first with the blocking solution (4% normal goat serum) for 30 min and then with the primary antibody (Oct-4: clone 9E3; SSEA-1: MC-480; SSEA-3: MC-631; SSEA-4: MC-813-70; TRA-1-60: clone TRA-1-60; and TRA-1-81: clone TRA-1-81, Chemicon� Inc., Temecula, CA, USA) at a dilution of 1:10 to 1:20 for 1 h. After being washed with DPBS, the embryos were incubated with appropriate FITC-labeled second antibody (anti-rat IgM or anti-mouse IgG or IgM, diluted 1:100 to 1:200) for 1 h and then examined under a fluorescence microscope. Oct-4 expression was detected at all embryonic stages starting from the 2-cell to the blastocyst stage, in which ICM, but not trophectoderm cells, exhibited a strong expression. SSEA-4 signal was found to be strongest at the 2-cell stage, with continued expression at all intermediate stages until the blastocyst stage in which there was a strong expression in ICM cells. In contrast, all of the embryonic stages were found to be negative for SSEA-3 expression. The SSEA-1 signal was present at all of the embryonic stages but was very weak. Expression of TRA-1-60 and TRA-1-81, which was detected only on the inner surface of the zona pellucida and in the perivitelline space in early embryonic stages, was absent in morulae and blastocysts. The results of this study indicate that the pluripotency-determining markers are differentially expressed in buffalo embryos and that the pattern of their expression is distinct from that of murine and human embryos but resembles to some extent that of goat embryos. Comparison of the expression pattern of these markers needs to be done between embryonic cells and ESCs for a better understanding of their developmental regulation.

165 EXPRESSION OF Oct-4 IN BUFFALO (BUBALUS BUBALIS) EMBRYOS GENERATED THROUGH IN VITRO FERTILIZATION OR PARTHENOGENETIC ACTIVATION

Octamer-4 (Oct-4) is a member of Class V of the POU transcription factors family, which is involved in transcriptional regulation during early embryonic development and cell differentiation. It is expressed in the inner cell mass of blastocysts and in embryonic stem cells (ESCs), and its expression is widely used as a marker of pluripotency in ESCs in many species. This study was, therefore, carried out to examine the expression of Oct-4 in embryos at the 2-, 4-, 8- to 16-cell, morula, and blastocyst stages generated through IVF or parthenogenetic activation. A total of 100 embryos were used in the study, 10 for each embryonic stage from both methods of embryo production. Immature oocytes obtained from slaughterhouse buffalo (Bubalus bubalis) ovaries were subjected to IVM in TCM-199 + 10% FBS + 5 µg mL–1 pFSH + 0.81 mm sodium pyruvate for 24 h in a CO2 incubator (5% O2, 5% CO2, 90–95% relative humidity) at 38.5�C. IVF was carried out immediately after IVM; the cleaved embryos were cultured for 8 days in CR2 medium containing 0.6% BSA and 10% FBS for production of embryos at different stages. For production of embryos through parthenogenesis, after 24 h of IVM, oocytes were denuded of cumulus cells by incubation in 0.2% hyaluronidase in Dulbecco's phosphate-buffered saline for 2 min. The denuded oocytes with a prominent polar body were parthenogenetically activated by exposure to 7% ethanol for 7 min, followed by incubation with 2 mm 6-dimethyl aminopurine in CR2 medium for 3.5 h in a CO2 incubator (5% O2, 5% CO2, 90–95% relative humidity) at 38.5�C, and then subjected to IVC as described above. A two-step RT-PCR was carried out using Cells-to-cDNA Kit-II (Ambion, Austin, TX, USA), using bovine primers 52-GTT CTC TTT GGA AAG GTG TTC-3' and 5'-ACA CTC GGA CCA CGT CTT TC-3' for the amplification of Oct-4. For this, the embryos were washed with PBS, transferred to 30 µL of cold cell lysis buffer and incubated in a thermal cycler at 75�C for 10 min. The cell lysate was treated with DNase-I at 37�C for 30 min to degrade genomic DNA and then heated at 75�C for 5 min to inactivate the DNase-I. The cell lysate (10 µL) was used for making cDNA using random primer. The PCR cycle included heating to 94�C for 2 min, followed by 33 cycles of 94�C for 30 s, 57�C for 30 s, and 72�C for 45 s. A final extension at 72�C for 10 min was carried out to complete the amplification of the Oct-4 gene. Transcripts of Oct-4 were detected at all of the embryonic stages, from the 2-cell through the hatched blastocyst stage in both IVF and parthenogenetically generated embryos. These results indicate that Oct-4, which is believed to be a reliable marker for pluripotency of ESCs in a number of species, is expressed in early cleavage-stage buffalo embryos and continues to be expressed in preimplantation-stage blastocysts.

Alterations in hypophysial responsiveness to synthetic GnRH at different postpartum intervals in Murrah buffalo (Bubalus bubalis )

The objective of this study was to investigate the hypophysial responsiveness to GnRH at different intervals post partum in Murrah buffalo. Plasma LH and FSH levels were measured at 1 h before and upto 6 h subsequent to the administration of GnRH (1 ug/kg body weight) or saline on Days 2, 20 and 35 post partum in 2 groups of buffalo (n=4 each). Plasma progesterone levels were measured in samples collected once daily from Day 3 to Day 46 post partum. Pretreatment basal LH levels exhibited a progressive increase from Day 2 through Day 35 post partum, while the basal FSH levels increased only until Day 20 post partum. Following a highly subdued LH response to GnRH on Day 2 post partum, a 408% increase (P < 0.01) was observed in the total LH released in response to GnRH on Day 20 post partum, followed by a 20% reduction (non-significant) over Days 20 to 35 post partum. The interval from parturition was highly correlated with total LH released (r = 0.711, P < 0.01). Unlike LH, a substantial amount of FSH was released following GnRH treatment on Day 2 post partum, which was not significantly different from the FSH response on Days 20 and 35 post partum. The LH and FSH response to GnRH was not significantly different between animals in which luteal activity resumed and in those which showed no luteal activity post partum. While pointing to a dramatic enhancement in the hypophysial responsiveness to GnRH between Days 2 and 20 post partum, these results suggest that pituitary responsiveness to GnRH does not appear to be the limiting factor for resumption of estrous cycles by Day 35 post partum in Murrah buffalo.

Isolation and characterization of embryonic stem cell-like cells from in vitro-produced buffalo (Bubalus bubalis) embryos

This study was carried out to isolate and characterize buffalo embryonic stem (ES) cell-like cells from in vitro-produced embryos. Inner cell mass (ICM) cells were isolated either mechanically or by enzymatic digestion from 120 blastocysts whereas 28 morulae were used for the isolation of blastomeres mechanically. The ICM cells/ blastomeres were cultured on mitomycin-C-treated feeder layer. Primary cell colony formation was higher (P < 0.05) for hatched blastocysts (73.1%, 30/41) than that for early/expanded blastocysts (25.3%, 20/79). However, no primary cell colonies were formed when blastomeres obtained from morulae were cultured. Primary colonies were formed in 14.1% (12/85) of intact blastocyst culture, which was significantly lower (P < 0.05) than that of 41.6% for ICM culture. These colonies were separated by enzymatic or mechanical disaggregation. Using mechanical disaggregation method, the cells remained undifferentiated and two buffalo ES cell-like cell lines (bES1, bES2) continued to grow in culture up to eight passages. However, disassociation through enzymatic method resulted in differentiation. Undifferentiated cells exhibited stem cell morphological features, normal chromosomal morphology, and expressed specific markers such as alkaline phosphatase (AP) and Oct-4. Cells formed embryoid bodies (EBs) in suspension culture; extended culture of EBs resulted in formation of cystic EBs. Following prolonged in vitro culture, these cells differentiated into several types of cells including neuron-like and epithelium-like cells. Furthermore, the vitrified-thawed ES cell-like cells also exhibited typical stem cell characteristics. In conclusion, buffalo ES cell-like cells could be isolated from in vitro-produced blastocysts and maintained in vitro for prolonged periods of time.

222 IN VITRO FERTILIZATION OF OOCYTES OBTAINED THROUGH TRANSVAGINAL OOCYTE RETRIEVAL FROM CYCLIC MURRAH BUFFALOES (BUBALUS BUBALIS)

Very limited information is available in the literature on in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) of oocytes collected through the transvaginal oocyte retrieval (TVOR) technique in buffaloes. Therefore, the present study was undertaken to examine the post IVF cleavage rates and embryonic development up to the blastocyst stage in the Murrah breed of buffalo subjected to TVOR. The five cyclic Murrah buffaloes were synchronized for estrus by a single prostaglandin injection. The animals were subjected to TVOR once weekly for seven weeks. TVOR was performed using an ultrasound machine with a transvaginal convex transducer (5 MHz), a needle guide, a single-lumen 19-gauge 60-cm-long needle, and a vacuum pressure of 50 mmHg. The number and size of follicles in each ovary was determined before puncture. The follicles were characterized on the basis of their diameter as small (3-5 mm), medium (6-9 mm), and large (e10 mm). The oocytes recovered were classified as grade A, cumulus-oocytes complexes with e5 layers of cumulus cells; grade B, those with two to four layers; grade C, partially denuded oocytes; and grade D, completely denuded oocytes. IVM, IVF and IVC were carried as reported by Chauhan et al. (1999 J. Dairy Science 82, 918-926). Briefly, the oocytes were cultured for 24 h in a CO2 incubator (5% CO2 in air) at 38.5�C for in vitro maturation. Frozen-thawed semen was used in Bracket and Olyphant medium for capacitation and fertilization. The in vitro-fertilized and cleaved embryos were cultured further for 9 days in modified synthetic oviductal fluid. The small follicles constituted a major proportion (60%) of the total observed follicles, although a substantial proportion of medium (19%) and large (21%) follicles were also present. A total of 76 oocytes were recovered by aspiration of 110 follicles, with an overall recovery rate of 70% (range 67-74%). Of these, 45 (59%) were of grades A and B, and 31 (41%) were of grades C and D. The mean number of total follicles and the oocytes recovered per session did not differ significantly among individual donors. Out of the 37 oocytes subjected to IVM and IVF, 19 (51%) cleaved at Day 2 post-insemination. A total of four embryos (11%) developed into morulae/blastocysts. This study demonstrates the use of TVOR as a mean of obtaining oocytes, their fertilization, and further embryo development in the Murrah breed of buffalo.

Repeated ultrasound-guided transvaginal oocyte retrieval from cyclic Murrah buffaloes (Bubalus bubalis): Oocyte recovery and quality

The present study was undertaken to explore the potential of the Murrah breed of buffaloes as donors of oocytes and to find out the recovery rate and oocyte quality in cyclic Murrah buffaloes subjected to oocyte recovery once a week. Murrah buffaloes (n = 5) were synchronized for estrus by a single prostaglandin injection schedule. The animals were subjected to transvaginal oocyte retrieval (TVOR) once weekly for 6 weeks, starting from Day 7 of the oestrous cycle (Day 0 = day of oestrus). TVOR was performed using an ultrasound machine with a 5 MHz transvaginal transducer, single lumen 19-gauge, 60 cm long needle and a constant vacuum pressure of 50 mmHg. The number and size of follicles in each ovary was determined before puncture. The follicles were characterized on the basis of their diameter as small (3-5 mm), medium (6-9 mm) and large (> or = 10 mm). The oocytes recovered were classified as grade A, cumulus-oocytes complexes (COCs) with > or = 5 layers of cumulus cells; grade B, those with two to four layers; grade C, partially denuded oocytes; and grade D, completely denuded oocytes. The mean (+/- S.E.M) number of small, medium and large follicles, and the number of total follicles observed per animal per session, which was 2.2 +/- 0.3, 0.6 +/- 0.2, 0.9 +/- 0.1 and 3.7 +/- 0.3, respectively, did not differ between animals or between puncture sessions. Small follicles constituted a major proportion (59%) of the total observed follicles. A mean (+/- S.E.M) number of 3.0 +/- 0.3 follicles were punctured and 2.0 +/- 0.3 oocytes recovered per animal per session, with a recovery rate of 68%. Out of the total 61 oocytes recovered, 36 (59%) were of grades A + B whereas 25 (41%) were of grades C + D. In conclusion, this study describes the potential of cyclic Murrah buffaloes as donors of oocytes collected by repeated TVOR once a week, without any adverse effects on follicular growth and oocyte recovery. It also describes an efficient system for carrying out TVOR in buffaloes.

195 DEVELOPMENT OF INNER CELL MASS AND FORMATION OF EMBRYOID BODIES ON A GELATIN-COATED DISH AND ON THE FEEDER LAYER IN BUFFALO (BUBALUS BUBALIS)

Isolation and culture of embryo-derived cell lines have been reported in many mammals, however, there is not even a single report toward initiation of such work in buffalo (Bubalus bubalis). Therefore the present study was carried out to isolate the inner cell mass from in vitro-produced buffalo blastocysts and to grow this inner cell mass for formation of embryoid bodies in a gelatin-coated dish and on an homologous fetal fibroblast feeder layer. Immature buffalo oocytes were isolated from the slaughterhouse ovaries. In vitro production of blastocysts was carried as reported by Chauhan et al. (1999 J. Dairy Science 82, 918-926). A total of 26 buffalo blastocysts were produced in vitro. These blastocysts were transferred into a 100-mL drop of Dulbecco's modified Eagle's medium (DMEM) supplemented with 20% fetal bovine serum (FBS) for further culturing. Thirteen blastocysts hatched on the next day of culture. The hatched mass was separated, suspended in Dulbecco's phosphate buffer saline (DPBS, without Ca++ and Mg++) containing 5% FBS + 0.25% trypsin and examined under the zoom stereomicroscope until disappearance of the trophectoderm cells. The remaining cells of seven blastocysts were cultured in DMEM supplemented with 20% FBS on 0.2% gelatin coated culture dish (group 1), and cells of six blastocysts in DMEM medium supplemented with 20% FBS were cultured on a mitomycin-c-treated (10 �L/mL) feeder layer (group 2), for 14 days. The isolated cells attached to the bottom of the dish in both the groups, spreading was noticed on Day 5 of the culture in group 1 and on Day 3 of culture in group 2. The attached cells were trypsinized using DPBS with 0.25% trypsin, isolated, and subcultured further. Attachment and spreading was noticed only in group 2 subcultured cells. The cellular integrity was homogeneous and the plasma membrane was clearly visible in group 2, but not in group 1. Less than 10% of the attached cells formed embryoid bodies in group 1, where as more than 30% attached cells in group 2 formed embryoid bodies; the latter expressed alkaline phosphatase activity and were blue after staining. These results indicate that the culturing of the inner cell mass on an homologous fetal fibroblast feeder layer is a better choice for production of embryonic stem cells in buffaloes.

Peripheral plasma FSH concentration in relation to expression of estrus in Sahiwal cattle (Bos indicus)

An experiment was conducted to investigate the changes in peripheral plasma FSH concentrations in relation to expression of estrus in Sahiwal cows. Out of total five estrus, three were accompanied by overt signs whereas rest two were silent estrus. In cows with overt estrus, plasma FSH concentrations during periestrus, early luteal, midluteal and late luteal phase were 1.65+/-0.34, 1.67+/-0.21, 1.58+/-0.18 and 1.69+/-0.31 ng/ml, respectively and the corresponding values in cows with silent estrus being 0.68+/-0.39, 0.50+/-0.12, 0.75+/-0.13 and 0.46+/-0.12 ng/ml, respectively. The overall plasma FSH levels in cows that exhibited overt estrus was 1.63+/-0.82 ng/ml as against 0.64+/-0.55 ng/ml in silent estrus. It was concluded that FSH levels were higher (P<0.01) in cows that exhibited overt estrus compared to silent estrus.

210INCREASE IN OVULATION RATE AFTER IMMUNIZATION OF MALPURA EWES AGAINST A SYNTHETIC PEPTIDE SEQUENCE OF THE ±-SUBUNIT OF BOVINE INHIBIN

Unlike many other breeds of sheep (e.g. Boroola, Romney or Merino) which have high fecundity, the Malpura ewe, an Indian breed of sheep, is marked by an ovulation rate of one and a low incidence of twinning. Active immunization against a number of inhibin-based synthetic peptides has been reported to increase ovulation rates in these high fecundity breeds of sheep. The objective of the present study was to explore the possibility of increasing ovulation rates in Malpura ewes by active immunization against a synthetic peptide replica of the N-terminal sequence of the bovine inhibin. Adult Malpura ewes (n=5) were actively immunized against a synthetic peptide that corresponded to the N-terminus of the α-subunit of bovine inhibin [bIα(1–29)Tyr30]. The peptide was conjugated to ovalbumin, with a peptide-to-ovalbumin ratio of around 20 moles mole−1, to increase its antigenicity. Control ewes (n=5) were immunized against ovalbumin. On the day of primary immunization, 400μg of peptide-ovalbumin conjugate or ovalbumin were dissolved in 1mL of isotonic saline, emulsified with an equal volume of Freund’s complete adjuvant and injected at four sites in each ewe. Following this, boosters 1, 2 and 3 were given on Days 28, 56 and 84, respectively, of the experiment (Day 0=day of primary immunization); boosters were 200μg of peptide-ovalbumin conjugate or ovalbumin dissolved in 1mL of isotonic saline and emulsified with an equal volume of Freund’s incomplete adjuvant. Estrus was synchronized by a double injection schedule of PGF2α (7.5mg Lutalyse, once each on Days 35 and 45). The animals were subsequently allowed to undergo normal cyclicity until the end of the experiment. Ovulation rate was determined by counting the number of corpora lutea observed during laparoscopic examinations approximately 5 days after estrus during three estrous cyles following treatment. The ovulation rate between control and immunized groups was compared by repeated measures ANOVA. Immunization of the Malpura ewes against the synthetic peptide sequence of the α-subunit of bovine inhibin [bIα(1–29)Tyr30] increased ovulation rate over 5-fold compared to that of controls (Table 1). In conclusion, we have shown that inhibin-based fecundity vaccines have the potential of increasing ovulation rates in the Malpura breed of sheep. Table 1