Milk, caseinate and lactoferrin addition to equine semen cooling extenders

Prolonged maintenance of stallion semen by optimization of cooling conditions

Bottlenecks to the success of equine assisted reproductive technologies (ART) include suboptimal conditions for prolonged storage of stallion sperm. Shipped stallion sperm are transported in cooling devices designed to maintain temperature for up to 48 h. Increasing the storage time of cooled semen while maintaining acceptable motility would relieve logistical ART challenges. Experiments were conducted to test the hypothesis that external regulation of shipment container temperature would prolong storage time of cooled stallion semen. Initial experiments determined the effect of pre-freezing cooling cans at -20 °C or -80 °C on sperm motility. Fresh sperm was extended in INRA96 and placed in commercial Equitainers for 3.5 days (84 h). Quantification of sperm kinematics was determined every 12 h. Sperm held in Equitainers with -20°C cans maintained higher total and progressive motility than -80 °C conditions at 60 h (63 %, 29 % vs. 32 %, 17 %, respectively). Internal monitoring of Equitainers containing -20 °C freezer can temperature identified 20 °C as the threshold for rapidly decreased motility. In the second experiment, sperm were maintained in Equitainers containing -20 °C freezer cans and placed in two different conditions: 1) ambient temperature for 48 h (23 °C) or 2) 5 °C for external temperature regulation up to 8 days, or when total motility dropped below 50 %. Sperm kinematics was determined every 24 h. Total motility from samples held with external temperature regulation (5 °C) remained above 50 % for more than 7 days. These findings suggest that cooled stallion semen can be advanced beyond traditional 48 h constraints by improving temperature maintenance of storage conditions.

Antioxidants in assisted reproductive technologies: An overview on dog, cat, and horse

Assisted reproductive technologies (ARTs) are widely used as a tool to improve reproductive performance in both humans and animals. In particular, in the veterinary field, ARTs are used to improve animal genetics, recover endangered animals, and produce offspring in the event of subfertility or infertility in males or females. However, the use of ARTs did not improve the fertilization rate in some animals due to various factors such as the difficulty in reproducing an anatomical and humoral substrate typical of the natural condition or due to the increase in catabolites and their difficult elimination. The in vitro environment allows the production and increase in the concentration of substances, including reactive oxygen species (ROS), which could be harmful to gametes. If produced in high concentration, the ROS becomes deleterious, both in vitro and in vivo systems. It has been seen that the use of antioxidants can help neutralize or counteract the production of ROS. The present study aims to report the latest findings regarding the use of antioxidants in ARTs of some domestic species, such as dogs, cats, and horses, compared to other animal species, such as cattle, in which ARTs have instead developed more widely.

Alternatives in Donkey semen cryopreservation: Mare vs. Jenny Colostrum

The aim of this study was to test and compare two new components in extenders for freezing donkey semen: mare colostrum and jenny colostrum. Colostrum was obtained from four mares and four jennies right after the foal's birth. Ejaculates were collected from five fertile donkeys. Sperm samples were pooled, diluted and cryopreserved in three different experimental extender groups: lactose supplemented with egg yolk extender (20%) as the control group, lactose supplemented with jenny colostrum extender (20%), and lactose supplemented with mare colostrum extender (20%). After thawing, we evaluated the sperm motility by means of computer-assisted analysis, viability by SYBR-14 and propidium iodide (PI), membrane functional by HOS test and acrosome integrity by isothiocyanate conjugated with peanut agglutinin (FITC-PNA) and PI. The results demonstrated that lactose-jenny colostrum extender displayed significantly higher values (p < .05) in nearly all parameters evaluated - Total Motility, Viability, HOS test, VCL, VSL, VAP, LIN, STR and WOB -, compared with mare colostrum and egg yolk extenders after thawing. In conclusion, the extender containing jenny colostrum used for donkey semen cryopreservation improved the donkey sperm quality after the freezing-thawing process.

Utilização de leite com diferentes concentrações de gordura como diluentes para sêmen equino refrigerado

Resumo Dois experimentos foram realizados para verificar a viabilidade de diluentes para sêmen equino refrigerado. O objetivo do primeiro experimento foi verificar a eficiência do leite UHT integral e semidesnatado, comparado ao leite desnatado. Amostras foram analisadas a fresco e posteriormente diluídas em leite UHT integral, semidesnatado e desnatado. Foram realizados exames de motilidade espermática e vigor, CFDA/PI e HOST pós-diluição (0h), e no sêmen refrigerado a 5 ºC após 24 e 48 horas. Não houve diferença entre os três diluentes, quanto à motilidade espermática (p=0,9880), vigor (p=0,7249), CFDA/PI (p=0,3382) e HOST (p > 0,01). Houve uma diminuição na qualidade do sêmen, no decorrer do tempo (p < 0,01), independente do diluente utilizado. Pode-se afirmar que, na falta de leite UHT desnatado, o semidesnatado e o integral podem ser usados, uma vez que eles não provocam prejuízo na qualidade do sêmen refrigerado armazenado por até 48 horas. No segundo experimento, o objetivo foi verificar a eficácia do leite desnatado em comparação com diluentes comerciais (Botusemen® (BS) e Botusemen Special® (BSS)). Logo após a coleta do sêmen, as amostras foram diluídas com leite UHT desnatado (LD), Botusemen® (BS) e Botusemen Special®(BSS). A análise de sêmen seguiu o mesmo protocolo do primeiro experimento. As amostras de sêmen refrigeradas com BSS apresentaram HOST e CFDA/PI (p< 0,001) maiores nas 24h e 48 h o que indica que o diluente BSS promove aumento da longevidade dos espermatozoides em comparação com os outros analisados.

Lactoferrin increases sperm membrane functionality of frozen equine semen

During cryopreservation, sperm was submitted to an increase in reactive oxygen species generation. This work aimed to improve the quality of frozen equine sperm after the addition of antioxidants lactoferrin (Lf) and catalase (Cat) to a freezing extender. Semen from six stallions was frozen with the extenders: F1) control, INRA 82 freezing extender, F2) F1 + 500 μg/ml Lf and F3) F1 + 200 IU/ml Cat. After thawing, sperm motility parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome-reacted sperm were evaluated with a computer-assisted sperm analysis, a hypoosmotic swelling test and epifluorescent microscopy, respectively. Nitrite, hydroperoxide and iron concentrations of frozen semen were measured with spectrophotometry. The percentage of functional membrane sperm treated with Lf was higher (50.7% ± 11.6%) compared to that of the control (37.6% ± 15.6%), while the iron (61.4 ± 11.6 vs 73.3 ± 13.8 mg/dl) and nitrite concentrations (16.3 ± 7.1 vs 25.9 ± 4.2 μM/μg protein) were lower, respectively (p < .05). Thus, it can be suggested that Lf protect stallion spermatozoon during freezing as it has increased the percentage of sperm with functional membrane and decreased the lipid oxidant agents.