Effect of low density lipoproteins in extender on freezability and fertility of buffalo (Bubalus bubalis) bull semen

Recent Advances in Applications of Bioactive Egg Compounds in Nonfood Sectors

Egg, a highly nutritious food, contains high-quality proteins, vitamins, and minerals. This food has been reported for its potential pharmacological properties, including antibacterial, anti-cancer, anti-inflammatory, angiotensin-converting enzyme (ACE) inhibition, immunomodulatory effects, and use in tissue engineering applications. The significance of eggs and their components in disease prevention and treatment is worth more attention. Eggs not only have been known as a "functional food" to combat diseases and facilitate the promotion of optimal health, but also have numerous industrial applications. The current review focuses on different perceptions and non-food applications of eggs, including cosmetics. The versatility of eggs from an industrial perspective makes them a potential candidate for further exploration of several novel components.

A systematic review and meta-analysis of spermatozoa cryopreservation, in vitro and in vivo fertility practices in water buffalo

We explored different aspects of buffalo spermatozoa during cryopreservation. The meta-data comprised of 285 studies, published from January 2008 to March 2020. A free web tool CADIMA as well as PRISMA 2009 Flow Diagram were used for carrying out this study. The inter-reviewer agreement among studies allocated was satisfactory for criteria A (selection bias), B (performance bias), C (detection bias) and D (attrition bias), respectively. India led the percent (%) research ladder with 34.4, followed by Pakistan (29.5), Egypt (12.3), Iran (7.7), Italy (5.6), Indonesia (3.2), China (2.1), Brazil (1.4), Thailand (1.1), Philippines and Bulgaria (0.7 each), Saudi Arabia, Turkey, Vietnam, and USA (0.4 each). Among four categories of studies, Group-1 evaluated only supplements/additives/media in the freezing semen extender (n = 191/285; 67.02%); Group-2 conducted in vivo fertilization (n = 62/285; 21.75%) and Group-3 conducted in vitro fertilization/ cleavage rate/penetration rate/ blastocyst yields (n = 28/285; 9.82%) with their specific cryodiluents/media, respectively. Group-4 conducted different experimental supplements/additives/media and carried out both in vitro and in vivo fertilization simultaneously (n = 4/285; 1.40%). Conventional spermatozoa cryopreservation was reported by 51.9% studies followed by programmable fast freezing by 20.7% studies. A few leading extender types included BioXcell (3.9%); Soyamilk-skim (3.5%); and Andromed (2.1%). The study also describes French straws for semen filling, cooling temperatures, extension time, equilibration time, cryopreservation stages, thawing temperatures, seasons, thawing time, and stains used during semen evaluation assays. The study concludes that the research on spermatozoa cryopreservation of buffalo is largely conducted at quality level and a need of applying these findings for evaluation of fertility potential (in vivo and in vitro) is indispensable for effective genetic improvement.

Effect of low-density lipoproteins and trehalose on the quality of cryopreserved bovine semen

Background: In artificial insemination, chicken egg yolk is added to bovine semen to protect it during the cryopreservation process, although it contains substances that can affect the microbiological quality and metabolism of sperm. Objective: To evaluate post-thaw quality of bovine cryopreserved semen added with centrifuged and non-centrifuged egg yolk, low-density lipoproteins (LDL), and trehalose (T). Methods: Ten ejaculates from five bulls were cryopreserved under the treatments T1: pure egg yolk (PEY) at 20% v/v, T2: centrifuged egg yolk (CEY) at 20% v/v, T3: LDL at 8% v/v, T4: T at 100 mM, and T5: T at 100 mM plus LDL at 8% v/v (TLDL). Spermatic motility and kinetics, functional membrane integrity (FMI), structural membrane integrity (SMI), sperm vitality (SV) and abnormal morphology (AM) were assessed using the Sperm Class Analyzer (SCA®) system, hypoosmotic test (HOST), SYBR/PI probes, and eosin–nigrosin staining, respectively. A completely randomized design was used. Normal distribution of the variables was validated through the Kolmogórov– Smirnov test. A generalized linear model was used to determine sources of variation. Means were compared using the Tukey test. Results: Inclusion of CEY or LDL had a similar effect on sperm protection, and were superior for motility, kinetics and membrane integrity compared to the other treatments (p<0.05). CEY was superior for progressive motility (p<0.05). The cryoprotective action of LDL was similar to TLDL for motility and kinetics, SMI, SV, and AM (p<0.05). Inclusion of PEY and T resulted in the lowest semen quality (p<0.05). The use of T resulted in a reduction in FMI and SMI (p<0.05). No differences in AM between treatments were found (p>0.05). Conclusions: Egg yolk can be replaced by centrifuged egg yolk or low-density lipoproteins in the freezing extender used for bovine semen used in artificial insemination.

Effectiveness of tes-tris or tris association with low density lipoprotein on in vitro longevity of refrigerated buffalo semen

ABSTRACT This study investigated in vitro the efficacy of four different extenders (TES-TRIS and TRIS with LDL low-density lipoprotein at concentrations of 10 or 5%) on the longevity of buffalo sperm in the refrigeration process at 5ºC. Sperm motility was assessed every 24 hours up to 72 hours of incubation using computer assisted sperm analysis and sperm membrane integrity was examined by the hypoosmotic test (HOST) at T1, T24, T48 and T72 hours. Eleven buffaloes (1 ejaculate per buffalo) of the Murrah breed were used, ranging in age from 4 to 5 years. Immediately after collection, each ejaculate was fractionated into 4 aliquots, and each aliquot was diluted in one of four diluents to obtain 50x106SPTZ/mL. The samples were packed in 0.5mL straws and refrigerated (-0.25°C/min) to 5°C and maintained at this temperature until evaluation. Prior to evaluation the samples were heated at 37°C for 30 seconds. The statistical package used for analysis was STATA 12.0 "Statistical Analysis Software" and means were compared by the Friedman test (P<0.05). The results of sperm kinetics and HOST indicate that the TRIS diluent with 10% LDL could be a promising alternative for semen refrigeration at 5ºC, to be used in conventional and fixed time artificial insemination.

Membrane stability and mitochondrial activity of bovine sperm frozen with low-density lipoproteins and trehalose

Cryopreservation results in the destabilization of the sperm plasma membrane, leading to negative side effects such as premature cryocapacitation, apoptosis and the low mitochondrial activity of bovine spermatozoa. Low-density lipoproteins (LDL) and trehalose have been used in seminal freezing to protect the integrity and stability of sperm membranes. Likewise, trehalose can increase the mitochondrial activity of sperm. The objective of this study was to evaluate the membrane stability and mitochondrial activity of bovine sperm after being frozen and treated with LDL sources and trehalose. Ten ejaculates from five bulls were cryopreserved under the treatments, CEY: chicken egg yolk (20% v/v); CCEY: centrifuged CEY (20% v/v); LDL: LDL (8% v/v); T: trehalose (100 mM); and TLDL: T (100 mM) plus LDL (8% v/v). After thawing, membrane stability and mitochondrial membrane potential (ΔΨM) were assessed by flow cytometry through the M-540/Yopro-1 and DiOC6/PI probes. The structural membrane integrity (SMI) was evaluated by fluorescence microscopy using SYBR14/PI dyes. A generalized linear model was adjusted, and the means were compared using the Tukey test. Centrifuged chicken egg yolk and LDL had a higher proportion of non-cryocapacitated non-apoptotic sperm (M-Y-), while CEY and T had the largest populations of cryocapacitated non-apoptotic sperm (M+Y-) and cryocapacitated apoptotic sperm (M+Y+). Centrifuged chicken egg yolk also showed a higher proportion of sperm with high-ΔΨM. Treatments that included egg yolk or purified LDL had a positive effect on SMI. Centrifuged chicken egg yolk has a superior cryoprotective effect on membrane stability and mitochondrial activity of bovine semen over the conventional use of CEY or the individual or simultaneous use of LDL and trehalose.

Dialysis of the goat semen and its effect on the quality of frozen/thawed spermatozoa processed in the presence of egg yolk

The aim of the present study was to analyze the effect of dialysis on the quality of frozen/thawed buck semen. Ejaculates (n = 15) from three Saanen bucks were divided into three experimental groups. Semen in Group Ce (centrifugation) was processed by standard method and washed two times at 1.085 × g for 20 min. During this time, the diluted control semen (Co) was stored at room temperature. Semen in Group D was dialyzed using 300 kDa cut-off semi-permeable cellulose tubing. The semen from all groups was diluted with extender containing 20% egg yolk and frozen in liquid nitrogen vapor. After thawing, semen samples were evaluated by microscopic and biochemical analyses. Phospholipase A2 was in amounts that was 72.0 ± 11.7% less after dialysis and 21.3 ± 10.0% less after washing with centrifugation compared to the control semen (P <  0.05). Spermatozoa from Group Co had a lesser motility and viability and greater percentage of morphological abnormal spermatozoa in comparison to Groups D and Ce at 3 h after thawing and incubation on 37 °C. At the same time motility and percentage of HOST positive spermatozoa were greater in Group Ce compared with D (P <  0.05). There, however, was no difference in morphology and viability (CFDA/PI analysis) of spermatozoa between Ce and D group. Results from the present study suggest the dialysis is the promising alternative method for reducing phospholipase A2 in the buck semen before cryopreservation.

Effect of egg yolk plasma and soybean lecithin on rooster frozen-thawed sperm quality and fertility

This experiment was conducted to study the effects of egg yolk plasma (10%, 15% and 20%), soybean lecithin (0.5%, 1% and 1.5%) and whole egg yolk (WEY) (control) on post-thawed sperm quality, hatchability and fertility outcomes. In experiment 1, sperm motility, abnormalities, membrane integrity, viability, apoptosis status, mitochondrial activity were studied following freeze-thawing. The best quality of frozen-thawed rooster sperm was chosen to be used for the assessment of the hatchability and fertility rate in experiment 2. The significantly higher percentages of post-thawing sperm total and progressive sperm motilities, membrane integrity, viability were observed in 1% soybean lecithin and 20% egg yolk plasma in comparison with 0.5 and 1% soybean lecithin, 10% egg yolk plasma and control, except for 15% egg yolk plasma (P < 0.05). Using 20% egg yolk plasma in the extender improved mitochondrial activity. Supplementation of 1% soybean lecithin and 20% egg yolk plasma into the extender resulted in the least percentages of dead sperm (P < 0.05). Sperm abnormalities and early apoptosis did not differ in various extender supplementations. In experiment 2, higher percentages of hatchability and fertility rate were observed in semen containing 1% soybean lecithin and 20% egg yolk plasma compared with the WEY group. The results showed that supplementation of the rooster sperm extender with 1% soybean lecithin and 20% egg yolk plasma resulted in higher quality of frozen-thawed sperm.

Recent Advances in Boar Sperm Cryopreservation: State of the Art and Current Perspectives

While sperm cryopreservation is the best technology to store boar semen for long-term periods, only 1% of all artificial inseminations (AI) conducted worldwide are made using frozen-thawed boar sperm. With the emergence of long-term extenders for liquid storage, the use of cryopreserved sperm in routine AI is less required. However, banks of boar semen contain cryopreserved sperm and planning inseminations in AI centres may benefit from the use of frozen-thawed semen. Therefore, there is an interest in the use of this technology to preserve boar sperm. In this regard, although the first attempts to cryopreserve boar semen date back to the seventies and this technology is still considered as optimal, some relevant improvements have been made in the last decade. After giving a general picture about boar sperm cryodamage, the present review seeks to shed light on these recent cryopreservation advances. These contributions regard to protein markers for predicting ejaculate freezability, sperm selection prior to start cryopreservation procedures, additives to freezing and thawing extenders, relevance of the AI-technique and insemination-to-ovulation interval. In conclusion, most of these progresses have allowed counteracting better boar sperm cryodamage and are thus considered as forward steps for this storage method. It is also worth noting that, despite being lower than fresh/extended semen, reproductive performance outcomes following AI with frozen-thawed boar sperm are currently acceptable.

Cryopreservation of rabbit semen using non-permeable cryoprotectants: effectiveness of different concentrations of low-density lipoproteins (LDL) from egg yolk versus egg yolk or sucrose

This study was designed to identify the most effective non-permeable cryoprotectant (CPA) for the cryopreservation of rabbit semen by comparing the effects of different concentrations of low-density lipoproteins (LDL) on post-thaw sperm quality with those of whole egg yolk or sucrose. In a second experiment, the performance of the non-permeable CPAs identified as most effective was assessed in vivo by determining reproductive performances. Pooled semen samples were diluted to a ratio of 1:1 (v:v) in freezing extender (Tris-citrate-glucose and 16% dimethylsulfoxide as permeable CPA) containing as non-permeable CPAs 6, 8, 10 or 15% LDL from egg yolk, 0.1M sucrose, or 15% egg yolk. The semen was loaded in 0.25mL straws and frozen in liquid nitrogen vapor. After thawing, we determined sperm motility, viability, osmotic resistance, and acrosome and DNA integrity. Our results clearly revealed a significant effect of LDL concentration on semen quality. Also, at an optimal concentration of 10%, motility and acrosome integrity were improved over the values recorded for egg yolk (P<0.05). Based on the in vitro data, 3 groups of does (n=30 each) were inseminated with fresh semen or semen frozen using sucrose or 10% LDL. Sucrose led to a significantly higher conception rate than LDL and reproductive performance was similar to that observed for fresh semen. Our findings indicate the markedly better performance of sucrose in vivo as a non-permeable CPA for the cryopreservation of rabbit semen.

The antioxidant effects of soybean lecithin- or low-density lipoprotein-based extenders for the cryopreservation of brown-bear (Ursus arctos) spermatozoa

Egg yolk low-density lipoproteins (LDL) and soybean lecithin were evaluated as replacements for egg yolk in extenders used for the cryopreservation of brown-bear spermatozoa. The motility, viability and acrosomal status of post-thawed spermatozoa were analysed, and an egg-yolk extender was used as a control. The total antioxidant capacity of these extenders was tested. Soybean lecithin showed an effect that was dependent on the soybean concentration (2%, 3.5% and 5%) and source (Type A: 24% L-α-phosphatidylcholine, and Type B: 14-23% L-α-phosphatidylcholine). Only semen cryopreserved with 5% Type A soybean exhibited a sperm motility similar to that of semen cryopreserved in egg-yolk-based extender after thawing, although the sperm viability and acrosome status were not as high. Semen frozen in an extender containing LDL (10-15%) exhibited improved sperm viability in comparison with the control, but sperm motility was lower. The LDL-based extender exhibited a higher anti-oxidant activity than the egg-yolk extender and soy lecithin-based extenders. The extenders with higher anti-oxidant activity showed improvements in frozen sperm viability but lower semen motility. These results indicate that soybean lecithin did not have the same protective effect as egg yolk during the freezing of brown-bear spermatozoa but suggest that LDL (10-15%) could be a useful substitute for egg yolk in these extenders.

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.