Superoxide Dismutase in Extender Improves the in vitro Quality and in vivo Fertility of Cryopreserved Water Buffalo (Bubalus bubalis) Spermatozoa

BACKGROUND

Superoxide dismutase (SOD) as an antioxidant in semen extender may be used for the cryopreservation of buffalo spermatozoa and in vivo fertility.

OBJECTIVE

This study was aimed to evaluate the effects of SOD (SOD1, 100 IU/mL; SOD2, 200 IU/mL; SOD3, 300 IU/mL) and control (0.0) in Tris citric acid extender on in vitro quality and in vivo fertility of cryopreserved water buffalo bull spermatozoa.

MATERIALS AND METHODS

Semen collection was carried out on a weekly basis (four bulls, three replicates, and n = 24 ejaculates). The conventional freezing of semen loaded straws (0.5 mL) was undertaken by placing them horizontally on a steel rack inside a Styrofoam box for 10 min containing liquid nitrogen (LN2) vapours, and plunging into a liquid nitrogen tank (-196 °C) for storage, followed by thawing at 37 °C for 30 s and analysis by computer-assisted sperm analyzer (CASA) and other assays.

RESULTS

At post-dilution, the acrosome integrity (ACR-I, %) was significantly improved (P < 0.05) in extender supplemented with SOD3 as compared to other experimental groups. In addition, DNA integrity (DNA-I, %) was significantly higher (P < 0.05) in SOD1 and SOD3 compared to SOD2 and control. At post-thawing, the mean values of sperm progressive motility (PM, %), average path velocity (VAP, µm/s) and straight line velocity (VSL, µm/s) were significantly higher (P < 0.05) in extender supplemented with SOD3 compared to the control. At post-thawing, mean values of subjective motility (SM, %), plasma membrane integrity (PMI, %) and ACR-I were significantly higher (P < 0.05) in extender supplemented with SOD3 compared to the control. At post-thawing, sperm DNA-I was significantly higher (P < 0.05) in extender supplemented with all SOD doses compared to the control in a dose-dependent manner. The in vivo fertility rate (%) was significantly higher with SOD3 compared to the control (68.2 % vs. 49.5 %).

CONCLUSION

The supplementation of SOD3 (300 IU/mL) in Tris citric acid extender improves both in vitro quality and in vivo fertility of buffalo bull spermatozoa.

Alpha-tocopheryl Succinate in Extender Improves the Post Thaw Quality of Water Buffalo Spermatozoa

BACKGROUND

Alpha-tocopheryl succinate, a major chain-splitting antioxidant, is the most effective form of vitamin E and may be used in the semen extender for cryopreservation of buffalo spermatozoa.

OBJECTIVE

To use different concentrations of alpha-tocopheryl succinate (T1, 0.3 mM, T2, 0.6 mM, and T3, 0.9 mM) and control (0.0 mM) in extender for dose optimization and hence improve the frozen-thawed quality of water buffalo spermatozoa.

MATERIALS AND METHODS

Semen samples were collected from three mature buffalo bulls with artificial vagina (42°C) and this study was replicated for five times. Semen was cryopreserved by conventional method which included filling of semen per experimental treatment into 0.5 mL French straws, sealing with polyvinyl alcohol powder and keeping them 5 cm above the liquid nitrogen vapors for 12 min and storing in liquid nitrogen tank. Frozen-thawed semen was also processed for total antioxidant capacity content (TAC) and lipid peroxidation (LPO) level by thiobarbituric acid (TBA). Computer-assisted semen analysis (CASA) and other assays were also performed.

RESULTS

TAC levels were higher (P<0.05) with T2 and T3 as compared to T1 and control. LPO levels were lower (P<0.05) with T2 and T3 as compared to T1 and control. Sperm progressive motility (%) and rapid velocity (%) were higher (P<0.05) with T2 and T3 as compared to control. The extender containing T3 had higher (P<0.05) sperm average path velocity (μm/s) and straight line velocity (μm/s) as compared to control. At 1 and 2 h incubation period (37 °C) T2 and T3 in extenders had higher (P<0.05) progressive motility and rapid velocity compared to control. Sperm supra vital plasma membrane integrity (%), mitochondrial transmembrane potential (%), viable and intact acrosome (%) and DNA integrity (%) were higher (P<0.05) with T2 and T3 as compared to T1 and control, respectively.

CONCLUSION

The supplementation of alpha-tocopheryl succinate in extender, either at 0.6 (T2) or 0.9 (T3) mM concentrations improves the post thaw quality of water buffalo spermatozoa by sustaining the TAC levels and keeping the LPO levels lower as compared to the control. It is suggested that future study should be aimed to explore the influence of these optimal concentrations of alpha-tocopheryl succinate on in vivo fertility of buffalo bull spermatozoa.

Effect of Cryopreservation on Casa Characteristics, Mitochondrial Transmembrane Potential, Plasma and Acrosome Integrities, Morphology and in vivo Fertility of Buffalo Bull Spermatozoa

BACKGROUND

Application of frozen-thawed semen is an important tool for improving the vivo fertility, but the process of freezing and thawing causes significant damage to spermatozoa.

OBJECTIVE

The aim of this study was to evaluate the effect of cryopreservation on CASA characteristics, mitochondrial transmembrane potential, plasma, and acrosome integrities, morphology and in vivo fertility of buffalo bull spermatozoa.

MATERIALS AND METHODS

Semen was collected from four mature buffalo bulls with artificial vagina at 42 °C. Ejaculates having > 1 mL volume, > 60 % sperm visual motility and > 0.5 x 10⁹ sperm/mL concentration from each bull were diluted in Tris-citric acid egg yolk glycerol extender (TCA) making two aliquots per bull for analysis at post dilution and cryopreserved respectively.

RESULTS

Analysis of variance (ANOVA) showed that the process of freezing and thawing significantly reduced (P < 0.05) CASA characteristics including total motility (TM, %), progressive motility (PM, %), rapid velocity (RV, %), average path velocity (VAP, µm/sec), straight line velocity (VSL, µm/sec), curvilinear velocity (VCL, µm/sec), beat cross frequency (BCF, Hz), straightness (STR, %) and linearity (LIN, %). Furthermore, the process of freezing and thawing significantly reduced (P < 0.05) subjective motility (SM, %), Supra-vital plasma membrane integrity (SVPMI, %), high mitochondrial membrane potential (HMMP, %), viable spermatozoa with intact acrosome (V/IACR, %). Moreover, it was observed that the freezing thawing process significantly decreased the in vivo fertility (%, 50.35 % vs. 61.39 %; P < 0.05) as compared to post diluted semen.

CONCLUSION

It is concluded that the process of freezing and thawing significantly reduced semen quality and in vivo fertility of buffalo bull in terms of various functional parameters.

Effect of EDTA as Chelating Agent in Extender on the Post Thaw Quality of Buffalo Bull Spermatozoa

BACKGROUND

Spermatozoa are prone to mechanical and biochemical stresses upon freezing. The influx of Ca⁺⁺ causes early capacitation and production of reactive oxygen species.

OBJECTIVE

To evaluate the effect of ethylenediaminetetraacetic acid (EDTA) as a calcium chelator in a semen extender.

MATERIALS AND METHODS

The effect of EDTA concentrations (0%, 0.1%, 0.2% and 0.3%) on the post thaw quality of buffalo bull spermatozoa were studied.

RESULTS

The extender with 0.2% EDTA improved significantly visual motility, progressive motility and plasma membrane integrity. Sperm kinematics, such as beat cross frequency (BCF), curved line velocity (VCL), straight line velocity (VSL) and average path velocity (VAP), were higher in the extender with 0.2% EDTA. EDTA at 0.2% improves semen parameters (visual motility, supra vital plasma membrane integrity, chromatin integrity and percentage viable spermatozoa with intact acrosome.

CONCLUSION

The EDTA supplementation in a semen extender improves the post-thaw quality of Nili-Ravi buffalo bull semen.

Programmable fast-freezing method improves the post-thaw motion dynamics, integrities of plasmalemma, mitochondrial transmembrane, DNA and, acrosome, and in vivo fertility of water buffalo (Bubalus bubalis) spermatozoa

The effects of freezing methods (FR1, nonprogrammable/static, 5 cm above liquid nitrogen [LN₂ ] for 10 min, plunging in LN₂ ; FR2, programmable medium, +4°C to -15°C at 3°C min^-1 , from -15 to -80°C at 10°C min^-1 and final holding for 1 min at -80°C, plunging in LN₂ ; FR3, programmable fast, from initial holding at +4°C for 2 min, from +4°C to -20°C at 10°C min^-1 , from -20°C to -100°C at 30°C min^-1 , final holding for 1 min at -100°C and plunging in LN₂ ) were assessed on post-thaw in vitro quality and in vivo fertility of water buffalo spermatozoa. Mean sperm progressive motility (%), rapid velocity (%), average path velocity (μm s^-1 ), straight line velocity (μm s^-1 ), curved line velocity (μm s^-1 ), integrities (%) of plasmalemma, mitochondrial transmembrane, DNA and acrosome were higher (p < .05) in samples cryopreserved with FR3 compared to FR1 and FR2. Similarly, in vivo fertility (%) of buffalo spermatozoa was higher (p < .05) with FR3 than FR1 (%; 68.0 versus 50.0). We concluded that programmable fast-freezing method (FR3) improves the post-thaw in vitro quality and in vivo fertility of water buffalo spermatozoa.

Freezability of water buffalo bull (Bubalus bubalis) spermatozoa is improved with the addition of curcumin (diferuoyl methane) in semen extender

Effects of curcumin as antioxidant in extender were evaluated on freezability of buffalo spermatozoa. Semen from each of the five bulls (n = 3 replicates, six ejaculates/bull, a total of 30 ejaculates) was diluted in Tris-citric acid extender containing curcumin (0.5, 1.0, 1.5 or 2.0 mM) or control. At pre-freezing and post-thawing, total antioxidant contents (μM/L) and lipid peroxidation levels (μM/ml) were higher (p < .05) and lower (p < .05) respectively, with 1.5 and 2.0 mM compared to 0.5 and 1.0 mM curcumin and control. At post-thawing, progressive motility (PM, %) and rapid velocity (RV, %) were higher (p < .05) with 1.5 mM compared to other doses of curcumin and control (except in case of RV, 1.5 was similar with 1.0 mM). Kinematics (average path velocity, μm/s; straight-line velocity, μm/s; curved-line velocity, μm/s; straightness, %; linearity, %), in vitro longevity (%, PM and RV) and DNA integrity (%) at post-thawing were higher (p < .05) with 1.5 mM compared to control. At post-thawing, supravital plasma membrane integrity (%) and viable spermatozoa with intact acrosome (%) were higher with 1.5 compared to 2.0 mM curcumin and control. We concluded that freezability of water buffalo spermatozoa is improved with the addition of 1.5 mM curcumin in extender.

Effect of equilibration times, freezing, and thawing rates on post-thaw quality of buffalo (Bubalus bubalis) bull spermatozoa

The effects of equilibration times (E1, 2 h; E2, 4 h; E3, 6 h), freezing rates (FR1, manual, 5 cm above liquid nitrogen (LN2 ) for 10 min, plunging in LN2 ; FR2, programmable ultra-fast, holding at +4 °C for 2 min, from 4 to -10 °C at -10 °C/min, from -10 to -20 °C at -15 °C/min, from -20 to -120 °C at -60 °C/min, holding at -120 °C for 30 sec, plunging in LN2 ), and thawing rates (T1, 37 °C for 30 sec; T2, 50 °C for 15 sec; T3, 70 °C for 7 sec) were evaluated on quality of buffalo bull spermatozoa. Progressive motility (%), rapid velocity (%), average path velocity (VAP, μm/s), straight line velocity (VSL, μm/s), and mitochondrial transmembrane potential (%) were higher (p < 0.05) with E2, FR2, and T3 compared to other groups. Sperm curved line velocity (VCL, μm/s) was higher (p < 0.05) with E2 and FR2 compared to other groups. Sperm straightness (%) and linearity (LIN, %) were higher (p < 0.05) with E2 compared to other groups. Sperm LIN was affected (p < 0.05) with T3 compared to other groups. Supravital-plasma membrane integrity (%), viability and acrosome integrity (%) of spermatozoa were higher (p < 0.05) with E2 and FR2 compared to other groups. Sperm DNA integrity (%) was higher (p < 0.05) with FR2 and T1 compared to other groups. We concluded that inclusion of 4 h-equilibration time, programmable ultra-fast freezing rate, and rapid thawing at 70 °C for 7 sec in cryopreservation protocol improves the post-thaw quality of buffalo bull spermatozoa.

Soya-lecithin in extender improves the freezability and fertility of buffalo (Bubalus bubalis) bull spermatozoa

Egg yolk is routinely used as a cryoprotectant in semen extenders. However, it may contain cryoprotective antagonists, and there are hygienic risks associated with its use. Proteins of plant origin, like soya-lecithin, lack these hazards. The aim of this study was to use soya-lecithin as a cryoprotectant in extender and to investigate its effects on in vitro quality and in vivo fertility of buffalo semen. Semen from three buffalo bulls was frozen in tris-citric extender containing 5.0%, 10% or 15% soya-lecithin or 20% egg yolk. Sperm motility, plasma membrane integrity and viability were assessed post-dilution, pre-freezing and post-thaw. In Post-dilution and pre-freezing, the values for motility, plasma membrane integrity and viability remained higher (p ≤ 0.05) in extenders containing 10% soya-lecithin and control compared with extender containing 5% and 15% soya-lecithin. However, motility, plasma membrane integrity and viability were higher (p < 0.05) in extender containing 10% soya-lecithin compared with control and extenders containing 5% and 15% soya-lecithin. Semen from two buffalo bulls was frozen in tris-citric extender containing either 10% soya-lecithin or 20% egg yolk. Higher (p < 0.05) fertility rate was recorded in buffaloes inseminated with semen containing 10% soya-lecithin (56%) compared with 20% egg yolk (41.5%). The results suggest that 10% soya-lecithin in extender improves the freezability and fertility of buffalo bull spermatozoa and can be used as an alternate to egg yolk in cryopreservation of buffalo semen.

In vitro evaluation of liquid-stored buffalo semen at 5°C diluted in soya lecithin based extender (Bioxcell®), tris-citric egg yolk, skim milk and egg yolk-citrate extenders

This study was designed to compare the quality of liquid-stored buffalo bull spermatozoa in soya lecithin based extender Bioxcell(®) (BIOX), milk (MILK), tris-citric egg yolk (TEY) and egg yolk-citrate (EYC) extender at 5°C. Semen was collected from five Nili-Ravi buffalo (Bubalus bubalis) bulls of 6-7 years of age with artificial vagina over a period of 3 weeks (two consecutive ejaculates once in a week). Semen ejaculates having more than 60% motility were pooled, split into four aliquots, diluted (37°C; 10 × 10(6) motile spermatozoa/ml), cooled from 37 to 5°C in 2 h (0.275°C/min) and stored for 5 days. Sperm motility, viability, plasma membrane integrity (PMI) and normal acrosomal ridge were studied at first, third and fifth day of storage. Higher values of progressive sperm motility (%), sperm viability (%), sperm PMI (%) and normal apical ridge (%) were observed in BIOX, MILK and TEY extenders at first, third and fifth day of storage than EYC extender. Progressive sperm motility, sperm viability and sperm PMI in BIOX(®) extender were not different from MILK and TEY extenders at 1st and third day storage period. However, at fifth day of storage, the values for these parameters remained significantly higher (p<0.05) in BIOX(®) compared with MILK, TEY and EYC extenders. At fifth day of storage, the semen quality parameters for Bioxcell(®) were comparable to those with MILK and TEY extenders at third day of storage. In conclusion, motility, viability and PMI of buffalo bull spermatozoa remained similar in Bioxcell(®) , milk and TEY extender at first and third days of storage at 5°C. Yet, the values for the aforementioned parameters in Bioxcell(®) were higher compared with milk, TEY and EYC extender at fifth day of storage at 5°C.

501. BACTERIOSPERMIA AND ITS CONTROL IN BUBALINE SEMEN

The present study was designed to investigate the bacterial species incriminated in bubaline semen and to find out the effectiveness of antibiotics (GTLS; gentamycin, tylosin and linco-spectin or SP; streptomycin and penicillin) in cryodiluent on bacterial control and quality of buffalo bull spermatozoa. For this purpose four experiments were conducted. In experiment 1, a total of 11 bacterial species were identified from buffalo ejaculates. The predominant bacteria were Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa in the ejaculates. In experiment 2, total aerobic bacterial counts in post-thaw samples were lower (P<0.05) in GTLS than in SP or NC (negative control). Fewer bacterial genera were identified in semen samples having GTLS than SP. Majority of the bacterial isolates from ejaculates showed more sensitivity towards GTLS than SP. In experiment 3, motilities (visual and computer-assisted), velocities (straight-line, average path and curvilinear), amplitude of lateral head displacement and plasma membrane integrity in post-thaw semen samples did not differ (P>0.05) due to antibiotics. Spermatozoal abnormalities (acrosome, head, mid-piece and tail) were lower (P<0.05) in GTLS and SP than in NC. In experiment 4, the fertility rates for SP-based vs. GTLS-containing frozen semen of buffalo bull were 42.8 and 55.2%, respectively. The results for GTLS were significantly higher than SP. The fertility rates also differed significantly in the first and second batch of inseminations performed with SP or GTLS-based cryopreserved semen of buffalo bull. In conclusion, a number of bacterial species are isolated from bubaline semen. Bacterial and seminal quality measured by standard laboratory tests and field fertility trials indicate that GTLS is more suitable in extender for cryopreservation of buffalo bull spermatozoa.

Duck egg yolk in extender improves the freezability of buffalo bull spermatozoa

We investigated the use of duck egg yolk (DEY), Guinea fowl egg yolk (GFEY) and Indian indigenous hen (Desi) egg yolk (IDEY) in extender for improving the post-thaw quality of buffalo (Bubalus bubalis) bull spermatozoa, and compared it with commercial hen egg yolk (CHEY; control). For this purpose, two consecutive ejaculates of semen from each of two Nili-Ravi buffalo bulls were collected on 1 day each week for 5 weeks (replicates; n=5) with artificial vagina (42 degrees C). Split pooled ejaculates, were diluted in tris-citric acid glycerol extender containing either DEY or GFEY or IDEY or CHEY at 37 degrees C. Extended semen was cooled to 4 degrees C in 2 h and equilibrated for 4 h at 4 degrees C. Cooled semen was then filled in 0.5 ml straws at 4 degrees C and frozen in programmable cell freezer. Thawing of semen was performed at 37 degrees C for 30 s. Sperm motility, plasma membrane integrity and sperm morphology (acrosome integrity, head, mid-piece and tail abnormalities) of each semen sample were assessed at 0, 3 and 6 h after thawing and incubation at 37 degrees C. Visual motility (%) and percentage of intact plasma membranes assessed at 6h post-thaw of buffalo bull spermatozoa were highest (P<0.05) due to DEY as compared to GFEY, IDEY and control. The percentage of spermatozoa with normal acrosomes at 0, 3 and 6 h post-thaw was highest (P<0.05) in DEY extender than GFEY, IDEY and CHEY. Sperm tail abnormalities (%) observed at 0, 3 and 6 h post-thaw in samples cryopreserved with freezing extender having DEY were lower (P<0.05) as compared to extender containing GFEY, IDEY and CHEY. In conclusion, DEY compared to other avian yolks in extender improves the frozen-thawed quality of buffalo bull spermatozoa.

Mammalian sperm chromatin structure and assessment of DNA fragmentation

This review article illustrates the biology of mammalian sperm chromatin structure. The possible causes of DNA (deoxyribonucleic acid) fragmentation are discussed. Also available molecular techniques for assessment of mammalian sperm DNA damage are described.

A review on reproductive biotechnologies for conservation of endangered mammalian species

This review describes the use of modern reproductive biotechnologies or assisted reproductive techniques (ART) including artificial insemination, embryo transfer/sexing, in vitro fertilization, gamete/embryo micromanipulation, semen sexing, genome resource banking, and somatic cell nuclear transfer (cloning) in conservation programs for endangered mammalian species. Such biotechnologies allow more offspring to be obtained from selected parents to ensure genetic diversity and may reduce the interval between generations. However, the application of reproductive biotechnologies for endangered free-living mammals is rarer than for endangered domestic breeds. Progress in ART for non-domestic species will continue at a slow pace due to limited resources, but also because the management and conservation of endangered species is biologically quite complex. In practice, current reproductive biotechnologies are species-specific or inefficient for many endangered animals because of insufficient knowledge on basic reproduction like estrous cycle, seasonality, structural anatomy, gamete physiology and site for semen deposition or embryo transfer of non-domestic species.

Serum Profiles of Luteinizing Hormone, Oestradiol and Cholesterol and Ovarian Functions in Layer Poultry Birds (Gallus domesticus) Fed Diets Containing Furazolidone

This study was carried out to assess the serum profiles of luteinizing hormone (LH), oestradiol, cholesterol and ovarian functions in layer poultry birds (Rhode Island Red: Gallus domesticus) fed a diet containing various concentrations of furazolidone (FZ). A total of 40 birds were randomly assigned to receive FZ 0, 200, 400 or 800 mg/kg feed (ppm) daily during the pre-laying age, i.e. 13-18 weeks (for 5 weeks). Blood samples were collected at weekly intervals. Concentrations of LH and oestradiol in serum were estimated at alternate weeks using radioimmunoassays. Serum cholesterol levels were analysed by an enzymatic calorimetric method. Furazolidone administration was terminated at the 18th week of age. The birds were sacrificed at 22nd week of age and ovarian tissues were processed for morphometric studies. Serum LH, oestradiol and cholesterol levels were affected by age (p < 0.001) and FZ dose (p < 0.001). Serum LH and oestradiol levels were lower (p < 0.05) in birds receiving FZ 800 mg/kg feed daily compared with the controls, whereas serum cholesterol profiles were lower (p < 0.05) in all FZ-administered groups than in the control group. The mean weight of ovaries having no yolky follicles observed in the group receiving FZ 400 or 800 mg/kg feed per day was reduced (p < 0.05) compared with the control group. Dosing FZ at 800 mg/kg feed per day reduced (p < 0.05) the mean volume of ovaries having no yolky follicles compared with the control group. In birds receiving FZ 800 mg/kg feed per day, the mean length of the oviduct was reduced (p < 0.05) as compared with the control group. Morphometric studies revealed that the mean number of oocytes with diameter in the range 401-800 microm decreased (p < 0.05) in birds fed FZ 400 or 800 mg/kg feed per day. Initial egg production was affected by age (p < 0.001) and dose (p < 0.001) of FZ. The mean number of eggs laid by different groups revealed that egg production was reduced (p < 0.05) in birds receiving FZ 800 mg/kg feed per day as compared with the controls. The present data suggest that FZ causes suppression in serum profiles of LH, oestradiol, cholesterol and ovarian functions in Rhode Island Red layer poultry birds. Therefore, great care must be taken with use of FZ in layer poultry birds (Gallius domesticus) with regard to dosage and duration of administration.

Sephadex and sephadex ion-exchange filtration improves the quality and freezability of low-grade buffalo semen ejaculates

The effect of sephadex and sephadex ion-exchange filtration on the improvement in quality and freezability of low-grade buffalo semen ejaculates was assessed. Two types of filtration columns were used: one containing only sephadex G-10 (FS) and the other sephadex G-10 along with ion-exchangers (diethyl amino ethane-52 (DEAE-52) cellulose and carboxy methyl-52 (CM-52) cellulose; FS+IE). Unfiltered samples served as controls. Semen ejaculates extended in Tris-citric acid (1:4) (n=16; initial motility 40-50%) were filtered at the rate of 1.5 ml/min under negative pressure at room temperature (28-30 degrees C). The mean recovery rate (%) of motile spermatozoa in the FS (85.9+/-1.51) and FS+IE (77.10+/-2.28) filtrates did not differ significantly. Percentages of sperm motility, normal acrosomes, and intact plasma membranes were highest (P<0.05) in FS+IE, intermediate (P<0.05) in FS and lowest (P<0.05) in controls at the three stages of cryopreservation (postfiltration final dilution, after equilibration, and after freezing). Mean sperm abnormalities were lowest (P<0.05) in the filtrates of FS+IE, moderate (P<0.05) in FS and highest in controls at all stages of freezing. Compared to dilution and equilibration, freezing greatly reduced (P<0.05) the overall percent motility, normal acrosomes and intact plasma membranes. The spermatozoa eluted through FS+IE columns proved more resistant (P<0.05) in bearing dilution, equilibration, freezing and thawing stresses than the spermatozoa from FS and control samples. It is concluded that filtration systems containing an FS+IE column can effectively enhance the quality and freezability of extended, low quality buffalo semen.