Semen Quality and Handling in Porcine Artificial Insemination

The success of porcine artificial insemination hinges on both the inherent quality of boar semen and the rigour of handling protocols. Semen quality is determined by attributes such as sperm motility, viability, morphology and DNA integrity. These parameters are sensitive to oxidative stress, temperature fluctuations and microbial contamination, all of which can impair fertilising potential. During collection, dilution and storage, extenders are used to support sperm metabolism, regulate pH and osmolarity, and limit bacterial proliferation. Traditional extenders often include antibiotics to suppress pathogens, but rising antimicrobial resistance drives research into antibiotic-free or alternative strategies. Hypothermic preservation at around 5 °C offers a means to slow bacterial growth without classical antibiotics, although it introduces chilling stress that must be mitigated by optimised cooling rates. Novel approaches such as dietary antioxidant supplements, probiotic-derived antimicrobials and photodynamic treatments are emerging. Practical handling factors—from vibration control during transport to strict hygiene measures—further influence global application in commercial breeding and underpin efforts to enhance fertility outcomes while adhering to animal welfare and sustainability goals.

Research from Nature Portfolio

Recent studies have explored non-antibiotic methods to curb bacterial contamination and preserve sperm function. One investigation demonstrated that cell-free supernatants from selected probiotic strains can inhibit common semen-origin pathogens carrying antimicrobial resistance genes, offering a bio-derived alternative to traditional antibiotics in extenders. These preparations reduced growth of Escherichia coli, Pseudomonas aeruginosa and Proteus mirabilis while maintaining sperm motility and membrane integrity. Another seminal work established an antibiotic-free hypothermic storage strategy at 5 °C using a premium extender. Sperm preserved under these conditions retained high motility, membrane and DNA integrity, and fertilising capacity over 72 h, with bacterial loads remaining below critical thresholds. Field fertility traits matched those obtained with antibiotic-supplemented extenders at 17 °C, underscoring the practical viability of antibiotic-free cooling protocols.

Semen Quality and Handling in Porcine Artificial Insemination publication trend

The graph below shows the total number of articles in semen quality and handling in porcine artificial insemination across all publications each year (not limited to Nature Index journals).

Technical terms

Semen extender: A specialised solution used to dilute and preserve semen, providing nutrients, regulating pH and osmolarity, and controlling microbial growth.

Hypothermic storage: Preservation of semen at low temperatures (circa 5 °C) to slow metabolism and bacterial proliferation while minimising chilling damage.

Oxidative stress: Imbalance between reactive oxygen species and antioxidants, leading to lipid, protein and DNA damage in spermatozoa.

Sperm capacitation: Biochemical changes that render sperm capable of fertilising an oocyte, often triggered by bicarbonate and calcium in the female tract or capacitation media.

Photodynamic inactivation: Use of a photosensitising agent and light to generate reactive oxygen species that selectively inactivate bacteria.

Antimicrobial resistance: The ability of bacteria to survive antimicrobial agents, posing a challenge for antibiotic-based semen preservation.

References

1. Supplementing Boar Diet with Nicotinamide Mononucleotide Improves Sperm Quality Probably through the Activation of the SIRT3 Signaling Pathway. Antioxidants (2024).
2. Storage of Extended Boar Semen at 5 °C Inhibits Growth of Multi-Drug Resistant Serratia marcescens and Klebsiella oxytoca while Maintaining High Sperm Quality. Antibiotics (2023).
3. Fertility after photodynamic inactivation of bacteria in extended boar semen. Frontiers in Microbiology (2024).
4. Antimicrobial activity of cell free supernatants from probiotics inhibits against pathogenic bacteria isolated from fresh boar semen. Scientific Reports (2023).
5. Sperm function in vitro and fertility after antibiotic-free, hypothermic storage of liquid preserved boar semen. Scientific Reports (2019).