Can rabbits store sperm? Yes, they can. Female rabbits store sperm from multiple males. In fact, some scientists believe that rabbits can store sperm indefinitely. However, the method of freezing sperms can cause cell damage. Researchers have found that sperms frozen at fast, medium and slow rates had lower quality than sperms frozen at a slow rate. One of the concerns is that ice crystal formation damages the cells. Hence, the freezing protocol should be improved to avoid this problem.
Female rabbits store sperm from multiple males
In a study, female rabbits can store sperm from two or more males. This allows females to bear more than one litter, or to have a larger ejaculate volume. This trait is especially useful in artificially producing multiple sperm in one litter. The study concluded that heterosis is common in rabbits. Some studies have shown that heterosis is significant in certain types of semen.
The reproductive health and performance of males are critical factors in success of a rabbit AI program. A male must possess large volumes of sperm, motility, viability, and healthy ovarian tissue. The objective of the AI procedure is to increase the likelihood of fertilized oocytes. Since the characteristics of the semen are highly variable, the number of doses required to achieve successful fertilization depends on the receptivity of the males. The amount of semen produced has a major impact on prolificacy. A male with a true cryptorchid scrotal sac will not produce ovulation.
Female insects store sperm from multiple males to enhance their offspring’s genetic diversity. They also store the sperm of multiple males to better adapt to various environments. A female Scathophaga, for example, preferentially fertilizes the eggs of males with the right genes for the environment. In a test tube, sperm from multiple males will fertilize the eggs, thereby ensuring greater genetic diversity.
Studies of sperm storage in female rabbits have also been conducted on mice. Using fluorescent dye, researchers were able to determine how many spermatozoa were successfully implanted in the oviducts. Furthermore, the presence of androgen binding proteins in the epithelial glands, as well as an androgen receptor, was found at the site of sperm storage. However, these findings do not explain the cryptic choice of a female.
Although the duration of female sperm storage varies from species to species, it appears to be shorter in reptiles and birds, but is longer in mammals. Females can use this trait to improve the quality of the males after copulation and the timing of conception. This is particularly important in species that live in areas with high sperm levels. It is thought that sperm storage can even extend the lifespan of a female rabbit.
As mentioned above, this trait of female rabbits is also helpful for reproductive research. Rabbits reproduce year-round, though their reproductive activity is concentrated between February and October. Therefore, the potential for rabbit populations to grow to millions is very high. It is estimated that a single female rabbit can bear from one to fourteen babies per litter. This is an incredibly useful trait for human reproductive research. And in addition to research, rabbits are a reliable food source worldwide.
Egg yolk provides optimal results in sperm cryopreservation
Egg yolks provide optimal results in sperm cryopreserveration in rabbits. Egg yolks, when mixed with TCGE cold storage agent, are known to preserve sperm without altering their morphology or changing their physiological characteristics. DMSO and glycerol are used as freeze protection agents. A mix of egg yolk and DMSO has been shown to improve sperm survival rates and quality.
The resulting sperm are more viable and more reproducible than eggs. Egg yolks contain lecithin, a phosphatidyl choline component that helps protect spermatozoa from cold shock during freezing and thawing. However, egg yolk is not available for every type of sperm cryopreservation procedure. Soy lecithin is an excellent substitute for egg yolk, and has minimal sanitary risks.
Studies using sperm cryopreservation in rats have demonstrated that egg yolk is more effective than DMSO in improving sperm quality. Egg yolk concentration and sperm motility improved with DMSO in rabbit spermatozoa cryopreservation experiments, but further study is needed to determine breed differences in sperm cryopreservation.
The use of egg yolk in sperm cryopreservation protocols has been improved by numerous investigations and experiments. The egg yolk contains many compounds beneficial to sperm. However, egg yolks introduce the risk of contamination with microbes. Therefore, egg yolks and sperm are subject to quarantine inspection before being processed for cryopreservation. However, the benefits are worth the negative aspects.
The slow cooling rate of egg yolks provided optimal results in rabbit sperm cryopreservation. Although egg yolks contain less water than other domestic species, the freezing rate of spermatozoa in this method is still lower. Also, rabbit spermatozoa have lower water permeability than those of other species. Thus, DMSO and acetamide are a good alternative for both DMSO and egg yolks.
In mice, the use of egg yolk in sperm cryopreservation has produced high rates of success. However, the sperm survival rate has varied with the method used. The Nakagata method was the most common and effective protocol for sperm cryopreservation in mice. It involves cooling samples in LN2 vapor phase for 5 min and plunges them into LN2 at -196degC. The Nakagata method has had few modifications to improve post-thaw fertility of mouse sperm.
Egg yolk improves rapid thawing of rabbit sperm
The quality of sperm in a frozen rabbit test tube increased when the sperm was treated with egg yolk. The same was true with chilled bull sperm and frozen-thawed sperm. Egg yolk was more effective than virgin coconut oil for improving sperm quality. However, there are limitations to this method. For example, rabbit sperm does not thaw as fast as human sperm, and it is not known if a small amount of egg yolk can improve the process.
Studies have shown that freezing rabbit sperm has a significant effect on their survival and fertility. Different methods of freezing and thawing were used. Egg yolk-acetamide extender provided substantial protection during freezing, but the egg yolk may have substantial damage to spermatozoa. A higher egg yolk content, however, may increase fertility. A higher egg yolk content may also reduce the rate of freezing, so that the thawing time remains consistent.
A recent study examined the viability and fertility of thawed rabbit sperm stored at various temperatures. The results showed that freezing sperm at 50 degrees Celsius was better than 70 degrees. In a separate study, Chen and Foote reported that thawing rabbit sperm at 65 degrees Celsius for 7 seconds had superior results. The authors conclude that thawing rabbit sperm at 50 degrees Celsius may improve fertility rates and viability.
Antioxidants are very efficient in improving the quality of post-thawing semen. They act on oxidative damage and ROS production in sperm cells. However, antioxidant radicals may have pro-oxidant properties. Further studies will have to clarify this question. However, egg yolk does not appear to cause harmful effects on rabbit sperm. This study is the first to prove this hypothesis.
In this study, vitamin E supplementation improved the quality of frozen-thawed rabbit sperm. The addition of vitamin E improved acrosome integrity, plasma membrane potential, and mitochondrial membrane potential. In addition, it protected sperm from damage caused by ROS and LPO. So, the next step is to evaluate the efficacy of vitamin E supplementation in rabbit sperm.
Trolox protects spermatozoa from lipid peroxidation during the freezing-thawing process. Other studies have demonstrated similar effects. A vitamin E analogue containing egg yolk improves rabbit sperm’s freezability and morphology. However, further studies are needed to determine whether or not these sugars have a negative effect on the entire population.