Effects of different extenders, storage temperatures, and antioxidant supplementation on chilled semen quality: a review.

The successful preservation of ram semen is essential to promote genetic variability, ensure semen transportation, and inseminate multiple ewes. Currently, either animal or plant-based lipoprotein-based extenders are used for semen preservation. Animal product-based extenders include milk and egg yolk, while soybean lecithin is a plant-based extender. Although extenders containing products of animal origin better preserve the quality of chilled semen, the in vivo efficacy after 24 h of storage is still of great concern. Storage temperature is another important and effective factor in preserving sperm quality, whereby different storage temperatures are adopted to enhance the storage life of sperm. Low temperatures (4-5 °C) better preserve sperm quality for a longer duration than high temperatures (15, 20, and 25 °C). Moreover, antioxidant supplementation has a positive impact on sperm quality during liquid storage. The current review summarizes the outcomes of various extenders, different storage temperatures, and antioxidant supplementation on the liquid storage of ram sperm.

Evaluating attributes of a collaborative model of service delivery for hereditary cancer risk assessment.

The purpose of this nonrandomized study was to compare several attributes of hereditary cancer risk assessment using a collaborative model of service delivery. Arm 1 included patients seen in-person by a board-certified genetic counselor (CGC), Arm 2 included high-complexity triaged patients from distant sites who received telegenetics with a CGC, and Arm 3 included low-complexity triaged patients from distant sites who had in-person risk assessment with a locally placed genetic counselor extender (GCE). A total of 152 patients consented and 98 had complete data available for analysis (35 in Arm 1, 33 in Arm 2, and 30 in Arm 3). The three groups were comparable in age, ethnicity, education, employment, and cancer status. There was no significant difference in median wait time or distance traveled to receive care across all three arms. However, if patients in Arms 2 and 3 had to access the CGC in-person, they would have had to travel significantly further (p < 0.0001). The time spent in a session was significantly longer in Arm 3 with a GCE than with a CGC in-person or by telegenetics (p < 0.01). There was no difference in the number of essential elements covered in the appointment, change in cancer worry, or appointment satisfaction across all three arms, although the sample size was small. Employing a collaborative model of service delivery with GCEs and telegenetics is feasible, satisfactory to patients and reduces the distance patients travel to access hereditary cancer genetic services.

Effect of freeze-dried quail egg white and yolk addition to semen extender on viability of rooster sperm stored for 6 h at 4°C.

The effect of freeze-dried quail egg white and yolk addition to basic EK extender on morphology and motility of chicken broiler breeder semen was investigated. Fresh pooled semen was divided into eight parts: fresh, undiluted (control), diluted in 1:2 ratio (v/v) with basic EK extender, EK + 200 mg/ml of egg white, EK + 100 mg/ml of egg white, EK + 50 mg/ml of egg white, EK + 100 mg/ml of egg yolk, EK + 50 mg/ml of egg yolk, EK + 25 mg/ml of egg yolk. Semen samples were evaluated 15 min after dilution and after 6 h of storage at 4°C. In the fresh semen, the number of live normal sperm was the highest in semen diluted with EK + 200 mg of egg white and EK + 100 mg of egg yolk, while the highest sperm motility was in the neat semen. Semen storage reduced the number of normal sperm in all analysed semen samples. In the neat semen, the number of normal sperm decreased, in relation to the fresh not-stored samples, by 36.8% (from 72.3% to 35.5%), with EK extender by 9.2%, in samples enriched with egg white, from 8.4% (EK + 200 mg) to 10.0% (EK + 100 mg), and in EK with egg yolk addition, from 1.2% (EK + 50 mg) to 10.6% (EK + 100 mg). The highest percentage of motile sperm was observed in EK extender enriched with 50 mg of egg white (77.1%) and EK + 25 mg of egg yolk (65.3%).

Effects of extender type and storage time on sperm quality parameters of Kail ram semen stored at 5 °C.

The study was designed to evaluate the effect of different extenders and storage times on sperm quality parameters of extended Kail ram semen. Semen was collected from five adult Kail rams using an artificial vagina. Semen samples with >70% total sperm motility were pooled, diluted with Tris (TR), sodium citrate (SC), and skim milk (SM)-based extenders, and stored at 5 °C. Sperm motility and kinematics, viability, and plasma and acrosomal membrane integrity were assessed every 24 hrs for 120 hrs. Sperm longevity was estimated by placing semen in a water bath at 37°C to assess sperm kinematics. Storage time as the main effect had a negative (P < 0.05) impact on sperm quality parameters. The percentages of total motile (TM), progressive motile (PM), rapid, and medium progressive (MP) motile sperm were similar at 24 hrs of storage for the three extenders. However, semen extended in TR had a higher (P < 0.05) percentage of TM, PM, rapid, and MP sperm compared to SM and SC extenders at 48 hrs of storage. The sperm kinematics (VCL, VSL, VAP, and ALH) of progressive sperm were similar for all three extenders up to 72 hrs of storage. In addition, semen extended in TR had a higher (P < 0.05) percentage of sperm with intact plasma and acrosomal membranes at a storage time of 48 hrs. At 37 °C, the percentage of TM and PM sperm was higher (P < 0.05) in the TR extender than in the SM and SC extenders at 60 minutes and beyond. In conclusion, the Kail ram sperm extended in TR and stored at 5 °C maintained better quality after 48 hrs storage than sperm extended in SM and SC extenders. At 37 °C, sperm extended in TR also retained better quality parameters at 60 min and afterward than sperm extended in SM and SC.

Preparation and Characterization of Water-borne Polyurethane Based on Benzotriazole as Pendant Group with Different N-Alkylated Chain Extenders and Its Application in Anticorrosion.

A series of novel anti-corrosive coatings were synthesized successfully. Water-borne polyurethane (WPU) was synthesized using polyethylene glycol and modified by grafting benzotriazole (BTA) as a pendant group (WPU-g-BTA) and N-alkylated amines (ethylene diamine (A), diethylene triamine (B), triethylene tetramine (C)) as side-chain extenders. Fourier-transform infrared spectroscopy, thermogravimetry, and dynamic mechanical analyses were used to characterize the structural and thermomechanical properties of the samples. A gas permeability analyzer (GPA) was used to evaluate molecular barrier properties. The corrosion inhibition performance of WPU-g-BTA-A, WPU-g-BTA-B, and WPU-g-BTA-C coatings in 3.5 wt% NaCl solution was determined by electrochemical measurements. WPU-g-BTA-C coating synthesized with a high cross-linking density showed superior anticorrosive performance. The as-prepared coatings exhibited a very low icorr value of 0.02 µA.cm-2, a high Ecorr value of -0.02 V, as well as excellent inhibition efficiency (99.972%) and impedance (6.33 Ω) after 30 min of exposure.

Sperm characterization and cryopreservation of the endangered freshwater fish Chirostoma estor (Atheriniformes).

The knowledge of the physiology of sperm of an endangered species allows the implantation of reproductive biotechnologies that aim at conservation. The aim of this study was to characterize fresh sperm and evaluate different cryopreservation solutions for sperm in Chirostoma estor. The characterization of Chirostoma estor fresh sperm (n = 22 males) was performed through analyzes of sperm concentration, membrane integrity, sperm morphology, motility rate, motility quality score, and motility duration. For cryopreservation (n = 42 males), 3 extenders (BTS™, MIII™, or Androstar Plus™) in combination with 2 permeable cryoprotectants (dimethyl sulfoxide (DMSO) or methyl glycol (Methyl)) were used. Analyzes of post-thaw sperm were performed as described for fresh sperm and additionally the fertilization rate analysis was performed. Fresh sperm presented a sperm concentration of 29.2 × 109 spermatozoa/mL, membrane integrity of 82.4%, and morphologically normal cells of 53%. After glucose activation (150 mM) a motility rate of 87.5%, sperm quality score of 5.0, and a duration of motility of 285 s were observed. For post-thaw sperm, MIII + Methyl and Androstar + Methyl solutions resulted in the highest motility rates of 40-48%. No differences were observed for motility duration, membrane integrity, and sperm morphology. Samples cryopreserved in Methyl (12-20%) showed a higher fertilization rate than DMSO, independently of the extender. In conclusion, the fresh sperm collected artificially from Chirostoma estor presents a compatible quality to carry out fertilization and can be cryopreserved in the commercial extenders MIII™ and Androstar Plus™ together with the cryoprotectant Methyl glycol.

In vitro evaluation of Labrador dog spermatozoa cryopreserved in Tris-citric acid-fructose buffer supplemented with different combinations of extracellular and intracellular cryoprotectants.

Aim of this study was to compare different combinations of penetrating intracellular CPAs, i.e., glycerol (G), ethylene glycol (EG), propylene glycol (PG), dimethyl formamide (DM), and methyl acetamide (MA) and extracellular [egg yolk (EY), egg yolk plasma (EYP), low-density lipoproteins (LDL), and coconut water (CW)] in Tris-citric acid-fructose buffer (T) for Labrador dog semen cryopreservation. The study was conducted in two parts, first trial was conducted to assess optimum glycerol concentration (5-7%) in TEY and equilibration time (ET, 2-4 hrs) for Labrador dog semen cryopreservation. Secondly, compatibility of 15% TEY, 15% TEYP, 13% TLDL, and 25% TCW with G, DMF, MA, D + M, EG, and PG was evaluated for in vitro sperm function tests. Decline in sperm attributes, i.e., motility, viability, plasma membrane integrity (PMI), and acrosome integrity (AI)) was significantly (p < 0.05) less in 7% TEY-G and 4 h compared to other concentrations and ET at post-thaw. There was significantly (p < 0.05) less decline in sperm attributes in TEY-G, TEYP-G, TLDL-G, TLDL-D, TLDL-EG, and TCW-D extenders compared to other combinations at post-thaw. However, these parameters were significantly (p < 0.05) high in TEY-G and TEYP-G compared to TEYP-D, TLDL-G, TLDL-D, TLDL-EG, and TCW-D extenders at post-thaw. However, decline in motility, viability, PMI, and AI was identical in these seven extenders. This study concluded that glycerol at a concentration of 7% in TEY and 4 h ET were optimum for successful cryopreservation and besides TEY-G, other combinations of protectants may be an alternative for canine semen cryopreservation.

Short-term cold storage of seminal samples of the golden lancehead pitviper (Bothrops insularis).

Assisted reproductive technologies such as cooling, freezing, and artificial insemination are essential in conserving genetic diversity of critically endangered reptiles like the golden lancehead pitviper (Bothrops insularis). Therefore, we examined viability of semen samples from captive golden lanceheads diluted in coconut-water based extender over a 48-h period of cooling (5°C). Semen evaluations were performed immediately after the dilution and at 6, 24, and 48 h, using computer-assisted sperm analysis and stains to assess plasma membrane and acrosomal status. Our findings showed that the extender and protocol employed here were effective in preserving golden lancehead pitviper spermatozoa for a short periods of time (48 h), allowing semen samples to be transported to distant locations for immediate use without the setbacks of cryopreservation.

Effects of extender type on the quality of post-thaw giant panda (Ailuropoda melanoleuca) semen.

Sperm cryopreservation is an essential approach for assisted reproduction and genetic resources conservation in captive giant pandas. Cryopreservation, however, leads to a significant decrease in sperm quality and, consequently, a low fertilization rate. Therefore, it is mandatory to disclose more suitable and efficient freezing strategies for sperm cryopreservation. In the present study, we compared for the first time the performance of two commercial freeze extender (INRA96 versus TEST) freezing methods on post-thawed semen quality. Semen cryopreserved with the INRA96 showed better total motility (73.00 ± 4.84% vs 57.56 ± 3.60%, P < 0.001), membrane integrity (60.92 ± 2.27% vs 40.53 ± 2.97%, P < 0.001) and acrosome integrity (90.39 ± 2.74% vs 84.26 ± 4.27%, P < 0.05) than stored with TEST. There was no significant difference in DNA integrity after thawing between the two extenders (95.69 ± 3.60% vs 94.26 ± 4.84%). In conclusion, the INRA96 method showed to be better for giant panda sperm cryopreservation and should therefore be recommended for use in order to increase success of artificial insemination.

Effect of semen extenders and storage time on quality of Muscovy duck (Cairina moschata) drake semen during the entire reproductive season.

Avian semen dilution with appropriate extender allows to prolong the fertilizing ability of sperm stored in vitro. In the present study, the impact of extenders and time of storage on morphology of Muscovy duck (Cairina moschata) drake semen were examined. Semen was collected twice a week, using male stimulation by a female method, from 12 adults (29 weeks old) drakes kept individually in cages, under controlled environmental conditions. Freshly collected, pooled ejaculates were divided into three part: neat undiluted sample, and diluted 1:1 with Schramm (SCH) or Watanabe (W) extender and stored at 4°C. Morphological examination of all samples was conducted after dilution and then, after 3 and 6 hr of storage. The storage of undiluted semen caused decrease (p ≤ .01) in live morphologically normal sperm, from 79.73% in the freshly collected ejaculates to 55.75% and to 12.12% after 3 and 6 hr of storage, respectively (average calculated for the entire reproductive season). In the semen diluted with Schramm's extender the adequate values attained 86.84, 79.65 and 61.66%, and using Watanabe extender 84.77, 83.58 and 75.25%, respectively. The period of semen storage and the type of extender caused significant (p ≤ 0,05; p ≤ 0,01) changes in sperm morphology. The longer period of storage contributed to the decrease in number of morphologically normal sperm, whereas their content in Watanabe extender after 3 and 6 hr of storage was higher (p ≤ .01) than in semen diluted in Schramm extender.

Semen cryopreservation in golden-headed lion tamarin, Leontopithecus chrysomelas.

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden-headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden-headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm-egg-binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short-term measure for the conservation of golden-headed lion tamarins.

Comparative effect of slow and rapid freezing on sperm functional attributes and oxidative stress parameters of goat spermatozoa cryopreserved with tiger nut milk extender.

Comparative effect of slow and rapid freezing on sperm functional attributes and oxidative stress parameters of goat spermatozoa cryopreserved with tiger nut milk (TNM) extender was examined in this study. Pooled semen samples obtained from West African Dwarf (WAD) goat bucks were diluted with Tris-based extenders containing different levels of TNM (0, 5, 10, 15 and 20 ml/100 ml extender). The diluted semen samples were subjected to slow and rapid freezing for a period of 7 days and thereafter evaluated for sperm functional attributes (percentage motility, acrosome integrity, membrane integrity, abnormality and livability) and oxidative stress (malondialdehyde [MDA] concentration and acrosin activity) parameters. Results showed that higher (p < 0.05) motility, livability, membrane and acrosome integrities in semen cryopreserved with slow freezing compared to rapid freezing. These parameters (motility, livability and membrane integrity) were higher (p < 0.05) in semen cryopreserved with 15% TNM in both slow and rapid freezing protocols. The results revealed that semen cryopreserved in slow freezing had lower (p < 0.05) abnormality compared to rapid freezing. Acrosin activity was higher in slow freezing compared to rapid freezing. Acrosin activity was higher at 15% TNM in both slow and rapid freezing. Lower (p < 0.05) MDA concentration was observed in semen cryopreserved using slow freezing compared to rapid freezing. The findings revealed improved post-thaw sperm functional attributes and oxidative stress parameters of WAD goat spermatozoa cryopreserved with 15% TNM using slow freezing.

Assessing practice pattern differences in the treatment of acute low back pain in the United States Military Health System.

BACKGROUND: Acute low back pain is one of the most common reasons for individuals to seek medical care in the United States. The US Military Health System provides medical care to approximately 9.4 million beneficiaries annually. These patients also routinely suffer from acute low back pain. Within this health system, patients can receive care and treatment from physicians, or physician extenders including physician assistants and nurse practitioners. Given the diversity of provider types and their respective training programs, it would be informative to evaluate variation in care delivery, adherence to clinical guidelines, and differences within the MHS among a complex mix of provider types. METHODS: This study was a retrospective, cross-sectional quantitative analysis that examined variations in treatment between provider types within the Military Health System in 2015 for treatment of acute low back pain using administrative data. In addition to descriptive and summary statistics, binomial logistic regression models were used to assess variation in practice patterns among physicians and mid-level practitioners for prescribing of non-steroidal anti-inflammatory, opioids, plain radiography, computed tomography, and magnetic resonance imaging. RESULTS: With regard to prescribing practices, results indicated that the odds of receiving non-steroidal anti-inflammatory prescriptions increased significantly for both physician assistants and nurse practitioners when compared to physicians. For basic radiological referrals, odds increased significantly for ordering plain radiography for physician assistants and nurse practitioners when compared to physicians. For more advanced imaging, odds significantly decreased for ordering computed tomography (CT) and slightly decreased for magnetic resonance for physician assistants, nurse practitioners and physician residents compared to the physician group. Additionally this study discovered differences in the prescribing patterns between provider categories. Both contractors and civilians had higher odds of prescribing opioids compared to active duty providers. CONCLUSIONS: As physician assistants and nurse practitioners continue to gain popularity as physician extenders in the US and in addressing provider shortages for the Military Health System, further research should be conducted to determine what impact, if any, the differences found in this study have on patient outcomes. In addition, provider type warrants further investigation to determine if labor mix and outsourcing decisions within a single payer system impacts health delivery and value based care.

New thermoplastic poly(carbonate-urethane)s based on chain extenders with sulfur atoms.

New thermoplastic segmented polyurethanes were obtained by a one-step melt polyaddition using 40, 50 and 60 mol% poly(hexane-1,6-diyl carbonate) diol of [Formula: see text] g mol-1, 1,1'-methanediylbis(4-isocyanatobenzene) and 2,2'-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol, 2,2'-[oxybis(benzene-1,4-diylsulfanediyl)]diethanol or 2,2'-[sulfanediylbis(benzene-1,4-diylsulfanediyl)]diethanol as a chain extender. FTIR, atomic force microscopy, differential scanning calorimetry and thermogravimetry were used to examine the polyurethanes' structure and thermal properties. Moreover, their Shore A/D hardness, tensile, adhesive and optical attributes were determined. They were transparent high-molar-mass materials showing good tensile strength (up to 51.9 MPa). The polyurethanes exhibited improved adhesion to copper taking into consideration that of conventional ones, and middle or high refractive index values (1.57-1.60), and both these parameters increased with an increase of the content of sulfur atoms in the polyurethane chain. The newly obtained polyurethanes can be considered as materials for numerous medical and optical appliances.

A collaborative approach to cancer risk assessment services using genetic counselor extenders in a multi-system community hospital.

PURPOSE: This study aimed to evaluate a unique approach to cancer risk assessment for improved access by smaller rural communities. METHODS: Local, on-site nurse navigators were trained and utilized as genetic counselor extenders (GCEs) to provide basic risk assessment and offer BRCA1/2 genetic testing to select patients based on a triaging process in collaboration with board-certified genetic counselors (CGCs). RESULTS: From August 2012 to July 2014, 12,477 family history questionnaires representing 8937 unique patients presenting for a screening mammogram or new oncology appointment were triaged. Of these, 8.2 % patients were identified at increased risk for hereditary breast cancer, and 4.2 % were identified at increased risk for other hereditary causes of cancer. A total of 75 of 1130 at-risk patients identified (6.6 %) completed a genetic risk assessment appointment; 23 with a GCE and 52 with a CGC. A review of the completed genetic test requisition forms from a 9-year pre-collaboration time period found that 16 % (20/125) did not appear to meet genetic testing criteria. Overall, there was a fourfold increase in patients accessing genetic services in this study period compared to the pre-collaboration time period. Efficiency of this model was assessed by determining time spent by the CGC in all activities related to the collaboration, which amounted to approximately 16 h/month. Adjustments have been made and the program continues to be monitored for opportunities to improve efficiency. CONCLUSION: This study demonstrates the feasibility of CGCs and GCEs collaborating to improve access to quality services in an efficient manner.

Easy and cheap way to prepare skin extenders.

Skin extender is a very useful method to repair wounds when oedema and skin retraction make a direct suture impossible. We have developed a new, simple and cheap way to prepare skin extenders based only on elastic vessel loops and metal clips stapler commonly used for skin suture and available in any operating room. This simple method can be performed both in the operating room and at the patient bedside, even under local anaesthesia, causes no bleeding and appears to be inexpensive and rapidly usable and should be made readily available in any hospital.

Patient safety in procedural dermatology: Part II. Safety related to cosmetic procedures.

Cosmetic procedures are growing in popularity and are associated with unique risks. Considering potential complications and prioritizing patient safety will help practitioners improve outcomes of elective procedures. In part II of this continuing medical education article, we provide a comprehensive review of patient safety in cosmetic procedures, including medical and legal issues surrounding the supervision and training of physician extenders.

Development and quality evaluation of dehydrated chicken meat rings using spent hen meat and different extenders.

It is recommended that for effective utilization of spent hen meat, it should be converted into value added or shelf stable meat products. Since we are lacking in cold chain facilities, therefore there is imperative need to develop shelf stable meat products. The present study was envisaged with the objective to develop dehydrated chicken meat rings utilizing spent hen meat with different extenders. A basic formulation and processing conditions were standardized for dehydrated chicken meat rings. Extenders such as rice flour, barnyard millet flour and texturized soy granule powder at 5, 10 and 15 % levels were incorporated separately replacing the lean meat in pre standardized dehydrated chicken meat ring formulation. On the basis of physico-chemical properties and sensory scores optimum level of incorporation was adjudged as 10 %, 10 % and 5 % for rice flour, barnyard millet flour and texturized soy granule powder respectively. Products with optimum level of extenders were analysed for physico-chemical and sensory attributes. It was found that a good quality dehydrated chicken meat rings can be prepared by utilizing spent hen meat at 90 % level, potato starch 3 % and refined wheat flour 7 % along with spices, condiments, common salt and STPP. Addition of an optimum level of different extenders such as rice flour (10 %), barnyard millet flour (10 %) and TSGP (5 %) separately replacing lean meat in the formulation can give acceptable quality of the product. Rice flour was found to be the best among the three extenders studied as per the sensory evaluation.

Polymer chain extenders induce significant toxicity through DAF-16 and SKN-1 pathways in Caenorhabditis elegans: A comparative analysis.

Polymer chain extenders, commonly used in plastic production, have garnered increasing attention due to their potential environmental impacts. However, a comprehensive understanding of their ecological risks remains largely unknown. In this study, we employed the model organism Caenorhabditis elegans to investigate toxicological profiles of ten commonly-used chain extenders. Exposure to environmentally relevant concentrations of these chain extenders (ranging from 0.1 µg L-1 to 10 mg L-1) caused significant variations in toxicity. Lethality assays demonstrated the LC50 values ranged from 92.42 µg L-1 to 1553.65 mg L-1, indicating marked differences in acute toxicity. Sublethal exposures could inhibit nematodes' growth, shorten lifespan, and induce locomotor deficits, neuronal damage, and reproductive toxicity. Molecular analyses further elucidated the involvement of the DAF-16 and SKN-1 signaling pathways, as evidenced by upregulated expression of genes including ctl-1,2,3, sod-3, gcs-1, and gst-4. It implicates these pathways in mediating oxidative stress and toxicities induced by chain extenders. Particularly, hexamethylene diisocyanate and diallyl maleate exhibited markedly high toxicity among the chain extenders, as revealed through a comparative analysis of multiple endpoints. These findings demonstrate the potential ecotoxicological risks of polymer chain extenders, and suggest the need for more rigorous environmental safety assessments.

Stallion Sperm Freezing with Different Extenders: Role of Antioxidant Activity and Nitric Oxide Production.

Sensitivity to freezing remains a critical issue in stallion semen cryopreservation procedures. To explore this topic in-depth, semen was collected from ten stallions, diluted with three different extenders, transported to the laboratory, and then centrifuged and frozen with four different extenders. We conducted analyses of sperm kinetics, mitochondrial membrane potential (MMP), and hydrogen peroxide content both before and after freezing. Additionally, we assessed antioxidant activity using the ABTS and FRAP methods and measured nitric oxide stable metabolites (NOx) in the blank extenders, seminal plasma, and extenders conditioned by spermatozoa before and after freezing. We found significant variability in the antioxidant activity and NOx content of the blank extenders and the seminal plasma. In the seminal plasma, ABTS-based antioxidant activity and NOx values were correlated with some sperm kinematic parameters and MMP in refrigerated semen, while no correlation was observed in frozen sperm parameters. Sperm function varied significantly between stallions but not between extenders, either before or after freezing. However, significant differences in antioxidant activities and NOx values were found among extenders conditioned following freezing. These results provide new insights into the factors contributing to the variability in individual stallions' tolerance to sperm freezing.