Gamete Therapeutics: Recombinant Protein Adsorption by Sperm for Increasing Fertility via Artificial Insemination

Abstract

A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs), specifically the fertility associated antigen (FAA) and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2), act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system’s response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA) and recombinant TIMP-2 (rTIMP-2) to bovine semen before cryopreservation for use in an artificial insemination (AI) program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus) heifers were selected based on their estrus cycle, body condition score (BCS), of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal) measurements. Heifers were synchronized using estradiol benzoate (EB), Celosil® (PGF2α) (Shering-Plough) and a controlled internal drug release (CIDR) device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL) and rTIMP-2 (25 µg/mL). In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037). Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented.

Effects of increased scrotal temperature on semen quality and seminal plasma proteins in Brahman bulls

“…Heparin binding proteins such as TIMP2 are acquired by the sperm during ejaculation, and expression have been identified in the bovine accessory sex glands (McCauley et al, 2001; Moura et al, 2006). Recombinant TIMP2 along with other heparin binding proteins, have been added to bovine semen before cryopreservation and AI, under tropical conditions, with a resulting positive effect on pregnancy rate (Alvarez‐Gallardo et al, 2013). NPC2 and TIMP2 have both previously been identified in SP from electroejaculated B. indicus bulls (Rego et al, 2014) and a previous study by our group identified NPC2, clusterin (CLU), and metalloproteinase inhibitor 2 to correlate negatively with the PNS (Boe‐Hansen et al, 2015).…”

Supplemented stallion seminal plasma can improve impaired motility due to the dilution effect in chilled Asian elephant sperm

“…In conclusion, elephant sperm were affected by a dilution effect and restoration of SP proportion with stallion SP improved the motility of chilled highly diluted sperm. Further identification of this supportive component may benefit the development of an appropriate extender or may allow treatment with direct addition to sperm used for AI in elephant, as has been carried out in bovine (Alvarez‐Gallardo et al., ) and in more sophisticated techniques in ram (Zalazar, Ledesma, Hozbor, & Cesari, ).…”

Application of Peptide for Improving Animal Health and Livestock Productivity

“…kimia heparin menyerupai glycosaminoglycans (GAGs) yang disekresikan dalam saluran reproduksi sapi betina (Alvarez-Gallardo et al 2013). Heparin dan GAGs pada saluran reproduksi sapi betina akan berikatan dengan protein pada permukaan sperma sapi jantan.…”