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Abnormalities in sperm genetic material can be expressed as maturation or nuclear condensation defects, DNA damage or breakdown and chromosomal abnormalities. Routine semen evaluation (sperm motility, concentration, viability, membrane function and morphology) does not reflect sperm DNA quality. This becomes important when applying assisted reproductive techniques, especially intracytoplasmic sperm injection, in which sperm with abnormal genomes can reach the oocyte’s genetic material. Three factors have been suggested to be involved in the etiology of DNA damage: oxidative stress, chromatin packaging anomalies and apoptosis. Various techniques have been used to study DNA defects. In general, DNA evaluation techniques can be divided into two groups: those that evaluate the degree of chromatin condensation or compactation and those that measure the degree of DNA fragmentation. Many of these techniques are laborious, costly and some depend on enzymes whose activity and accessibility to DNA fragments can be irregular. In this article, the development and setting up of various techniques to evaluate sperm chromatin in South American Camelids (SACs) and other domestic species is commented on.

Seminal plasma (PS) acts as a transport medium for sperm through the reproductive tract of the female and male, regulates the osmolarity of the ejaculate through the inorganic components, is a source of energy for sperm, provides buffer protection against pH changes, protects sperm from the deleterious effects of reactive oxygen species through their antioxidant enzymes and regulates the female reproductive tract's immune response. PS proteins have been associated with fertilization events such as sperm maturation, sperm capacitation, interaction with the oviduct and are even involved in the interaction with the oocyte. In many species, PS is routinely diluted or removed during the semen cryopreservation process; this can have positive and/or negative effects on sperm function and fertility. The PS has also been added after the cryopreservation process. The effects that PS has on cryopreserved spermatozoa vary between species, between individuals of the same species and between ejaculates of the same individual. Despite a notable advance in the knowledge of the functions of PS, there is still controversy about the precise role of SP in sperm function, male fertility and its effect on cryopreserved spermatozoa.

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