Curcumin Attenuates Damage to Rooster Spermatozoa Exposed to Selected Uropathogens

Abstract

Artificial insemination, as an essential pillar of the modern poultry industry, primarily depends on the quality of semen collected from stud roosters. Since the collection and storage of ejaculates is not a sterile process, antimicrobial agents have become essential supplements to semen extenders. While the use of traditional antibiotics has been challenged because of rising bacterial resistance, natural biomolecules represent an appealing alternative because of their antibacterial and antioxidant properties. As such, this study strived to compare the effects of 50 μmol/L curcumin (CUR) with 31.2 µg/mL kanamycin (KAN) as a conventional antibiotic on rooster sperm quality in the presence of Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa. Changes in sperm structural integrity and functional activity were monitored at 2 and 24 h of culture. Computer-assisted semen analysis revealed significant sperm motility preservation following treatment with KAN, particularly in the case of Salmonella enterica and Pseudomonas aeruginosa (p < 0.001) after 24 h. On the other hand, CUR was more effective in opposing ROS overproduction by all bacteria (p < 0.05), as determined by luminol-based luminometry, and maintained sperm mitochondrial activity (p < 0.001 in the case of Salmonella enterica; p < 0.05 with respect to Escherichia coli and Pseudomonas aeruginosa), as assessed by the fluorometric JC-1 assay. The TUNEL assay revealed that CUR readily preserved the DNA integrity of rooster sperm exposed to Salmonella enterica (p < 0.01) and Escherichia coli (p < 0.001). The bacteriological analysis showed higher efficiency of KAN in preventing the growth of all selected bacterial species (p < 0.0001) as opposed to CUR. In conclusion, CUR provided protection to rooster spermatozoa against alterations caused by uropathogens, most likely through its antioxidant activity. Hence, CUR supplementation to poultry semen extenders in combination with properly selected antibacterial substances may become an interesting strategy in the management of bacterial contamination during semen storage.

Short-Term Storage of Rooster Ejaculates: Sperm Quality and Bacterial Profile Differences in Selected Commercial Extenders

“…Extenders for poultry semen are available with or without antibiotics, and if antibiotic-free media are used, antibacterial substances should be administered to accommodate the European Directive 90/429/EEC [ 10 , 28 ]. In this study, we purchased commercially available avian media without antibiotics and chose to supplement these with 31.2 µg/mL KAN based on our previous reports [ 19 , 29 ]. Nevertheless, this study reveals that bacterial presence in extended semen is a common phenomenon, and antibiotic supplementation may exhibit only a limited control of bacterial persistence and growth during storage.…”

“…Being an aminoglycoside antibiotic, KAN has a broad spectrum of activity against both Gram-positive and Gram-negative bacteria, which is why it is, along with gentamicin, a popular antibiotic supplement to semen diluents in farm animals [ 19 , 27 , 28 , 29 , 30 ]. Nonetheless, an alarming occurrence of bacterial tolerance and/or resistance towards conventional antibiotics urges us to approach antibiotic supplementation in animal production with caution.…”

“…In this study, 24 h of semen storage resulted in reduced sperm structural integrity and functional activity, depending on the diluent, presence, or absence of the antibiotic and the corresponding extent of bacterial contamination ( Supplementary Tables S2–S8 ). Accordingly, the diluents free from KAN were unable to control bacterial growth and activity, leading to adhesion and agglutination processes that may subsequently compromise the integrity of the sperm membranous structures [ 18 , 19 , 41 , 42 ] and cease the metabolic activity of male gametes [ 19 , 41 ]. Furthermore, bacteria such as E. coli or staphylococci may adhere to the flagellar structures, causing the sperm flagellum to break, knot or tear off and thus impede the normal motion behavior of the sperm cell [ 18 , 19 ].…”

“…Accordingly, the diluents free from KAN were unable to control bacterial growth and activity, leading to adhesion and agglutination processes that may subsequently compromise the integrity of the sperm membranous structures [ 18 , 19 , 41 , 42 ] and cease the metabolic activity of male gametes [ 19 , 41 ]. Furthermore, bacteria such as E. coli or staphylococci may adhere to the flagellar structures, causing the sperm flagellum to break, knot or tear off and thus impede the normal motion behavior of the sperm cell [ 18 , 19 ]. The sperm’s vitality and fertilization ability may be further endangered by the release of bacterial endotoxins such as lipopolysaccharide (LPS), hemolysin, or peptidoglycan fragments, which may deteriorate the plasma membrane’s integrity, fluidity, and semi-permeability [ 43 , 44 ].…”

“…Previous studies have additionally revealed that bacterial contamination of extended semen has led to sperm agglutination [ 16 ], motility inhibition [ 17 , 18 ] and alterations to the sperm morphology [ 18 ], rendering the affected semen sample ineffective in accomplishing fertilization. Bacterial activity may contribute to increased reactive oxygen species (ROS) levels [ 19 ], which, together with metabolic by-products and toxins, significantly contribute to a reduced shelf-life of insemination doses [ 10 , 20 ]. The use of contaminated semen may subsequently cause infection and infertility in the female following insemination or result in the spread of diseases in the flock [ 21 ].…”