Santiago Peña - Academia.edu (original) (raw)
Papers by Santiago Peña
Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particu... more Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particularly in the tropics, costing the industry millions in annual loses. The boar's reduced capacity to sweat, non-pendulous scrotum, and widespread use of European breeds in the tropics, makes this species particularly vulnerable to heat stress. While traditionally considered a sow problem, recent mouse studies demonstrate that heat stress-induced sperm DNA damage can result in arrested development and loss of early embryos. Our study investigated the impact of tropical summer heat stress on the quality and DNA integrity of boar sperm, and trialled antioxidant supplementation to alleviate the problem. Motility of sperm obtained from n = 5 Large White boars housed in the dry tropics of Townsville, North Queensland, Australia was characterized by Computer-Assisted Sperm Analysis but did not differ between summer, winter or spring (total motility: 71.3 ± 8.1 vs. 90.2 ± 4.2 vs. 70.8 ± 5.5% ...
At 40% share, pork is the most widely eaten meat globally. As such, research efforts must improve... more At 40% share, pork is the most widely eaten meat globally. As such, research efforts must improve production and efficiency in the pig industry to meet growing demand. However, summer heat stress has a significant negative impact on pig fertility; causing embryonic death and decreased litter size that cost the industry millions in productivity losses. This problem is particularly prevalent in the tropics where ambient temperatures rise beyond the animal’s zone of thermal comfort. Boars are particularly vulnerable to the effects of heat stress due to their inefficient capacity to sweat; non-pendulous scrotum; and the high susceptibility of boar sperm to temperature shock. Moreover, due to limited endogenous antioxidant systems inherent in mammalian spermatozoa and the loss of cytosolic repair mechanisms during spermatogenesis, the DNA in these cells are particularly susceptible to oxidative damage. While a seemingly healthy looking sperm may swim and fertilize an oocyte normally, stu...
The use of frozen-thawed boar sperm still lags behind chilled boar semen in artificial inseminati... more The use of frozen-thawed boar sperm still lags behind chilled boar semen in artificial insemination (AI) operations despite its advantages [1]. Freezing however, may damage the structure and function of sperm, leading to reduced fertilization success. Moreover, glycerol, which is a critical cryoprotectant in most sperm freezing protocols, can be toxic to cells in high concentrations [2]; affecting sperm motility and acrosomal integrity. This study was conducted to determine the cryoprotective effect of glycerol on sperm DNA integrity and motility in frozen-thawed boar sperm.
Background: Summer infertility due to heat stress significantly affects the reproductive potentia... more Background: Summer infertility due to heat stress significantly affects the reproductive potential of pigs causing over $300 million per year in lost productivity to the US pig industry and billions worldwide. The boar's inefficient capacity to sweat; non-pendulous scrotum, and the high susceptibility of boar sperm to temperature shock appears to correlate with higher sperm DNA damage during summer. Heat stress-induced sperm DNA damage can result in early embryo loss, as demonstrated in mice. This study investigated whether supplementing boars with antioxidants during summer could improve boar sperm DNA integrity. Method: Motility of sperm obtained from n=5 Large White boars housed in the dry tropics of Townsville, Queensland, Australia were analysed using Computer-Assisted Sperm Analysis. Sperm DNA integrity during summer was compared without or after 42 and 84 days antioxidant supplementation, by Terminal deoxynucleotidyl transferase dUTP Nick-End Labelling and flow cytometry....
Introduction: While pork is the most widely eaten meat in the world, pig production is continuall... more Introduction: While pork is the most widely eaten meat in the world, pig production is continually threatened by changing climate conditions resulting in poor reproductive performance, particularly in the tropics. The boar's inefficient capacity to sweat; non-pendulous scrotum and high susceptibility of boar sperm to temperature shock makes this species particularly vulnerable to the effects of heat stress. While DNA-damaged sperm may fertilize normally, key genes involved in early embryo development may be severely affected inducing early embryo loss as shown in the mice. Our study demonstrates that tropical summer significantly increases DNA damage in populations of sperm within the ejaculate without necessarily affecting sperm motility. Moreover, supplementing boars with antioxidants during summer could potentially reduce the negative impact of heat stress on sperm DNA integrity. Materials and Methods: Five mature Large White boars were housed individually in open gable pens ...
Reproduction, Fertility and Development, 2018
Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particu... more Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particularly in the tropics, costing the industry millions in annual losses. The boar’s reduced capacity to sweat and non-pendulous scrotum, combined with the widespread use of European breeds in the tropics, makes this species particularly vulnerable to heat stress. Although heat stress is traditionally considered a sow problem, recent mouse studies demonstrate that heat stress-induced sperm DNA damage can result in arrested development and loss of early embryos. Our study investigated the impact of tropical summer heat stress on the quality and DNA integrity of boar sperm, and trialled antioxidant supplementation to alleviate the problem. Data, expressed as mean ± SEM, were analysed by one-way repeated-measures ANOVA with pairwise Bonferroni tests. Motility of sperm obtained from Large White boars (n = 5) housed in the dry tropics of Townsville, North Queensland, Australia, was characterised ...
Animal Production Science, 2017
Temperature is a crucial factor in mammalian spermatogenesis. The scrotum, pampiniform plexus, an... more Temperature is a crucial factor in mammalian spermatogenesis. The scrotum, pampiniform plexus, and cremaster and dartos muscles in mammals are specific adaptations to ensure sperm production in a regulated environment 4−6°C below internal body temperature. However, the limited endogenous antioxidant systems inherent in mammalian spermatozoa compounded by the loss of cytosolic repair mechanisms during spermatogenesis, make the DNA in these cells particularly vulnerable to oxidative damage. Boar sperm is likely to be more susceptible to the effects of heat stress and thus oxidative damage due to the relatively high unsaturated fatty acids in the plasma membrane, low antioxidant capacity in boar seminal plasma, and the boar’s non-pendulous scrotum. Heat stress has a significant negative impact on reproductive performance in piggeries, which manifests as summer infertility and results in productivity losses that amount to millions of dollars. This problem is particularly prevalent in tr...
Theriogenology, 2015
The sperm reservoir is formed when spermatozoa bind to the epithelium of the utero-tubal junction... more The sperm reservoir is formed when spermatozoa bind to the epithelium of the utero-tubal junction and caudal isthmus of the oviduct. It is an important mechanism that helps synchronize the meeting of gametes by regulating untimely capacitation and polyspermic fertilisation. This study investigated the influence of epididymal maturation and caudal fluid on the ability of spermatozoa to bind to oviduct epithelium using a model porcine oviduct explant assay. Spermatozoa from the rete testis, middle caput (E2-E3), middle corpus (E6) and cauda (E8) of Large White or Large White x Landrace boars at 10-14 months of age were diluted in modified Androhep solution and incubated with porcine oviduct explants. Results reported in this study support our hypothesis that testicular spermatozoa need to pass through the regions of the epididymis in order to acquire the ability to bind to the oviduct. There was a sequential increase in the number of spermatozoa that bound to 28 oviduct explants from the rete testis to caudal epididymis. Binding of caudal 29 spermatozoa to isthmic explants was the highest (15.0 ± 1.2 spermatozoa per 1.25 30 mm 2 ; mean ± standard error of the mean; P ≤ 0.05) and lowest by spermatozoa from the rete testis (2.0 ± 0.3 per 1.25 mm 2), and higher to isthmus from sows compared to gilts (35.8 ± 6.7 per 1.25 mm 2 vs. 14.8 ± 3.0 per 1.25 mm 2 ; P ≤ 0.05). Binding of ejaculated spermatozoa to porcine isthmus was higher than for caudal spermatozoa (26.3 ± 1.4 per 1.25 mm 2 vs. 15.0 ± 0.8 per 1.25 mm 2 ; P ≤ 0.05), and higher to 35 porcine than to bovine isthmus (26.3 ± 2.3 per 1.25 mm 2 vs. 18.8 ± 1.9 per 1.25 mm 2 ;
Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particu... more Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particularly in the tropics, costing the industry millions in annual loses. The boar's reduced capacity to sweat, non-pendulous scrotum, and widespread use of European breeds in the tropics, makes this species particularly vulnerable to heat stress. While traditionally considered a sow problem, recent mouse studies demonstrate that heat stress-induced sperm DNA damage can result in arrested development and loss of early embryos. Our study investigated the impact of tropical summer heat stress on the quality and DNA integrity of boar sperm, and trialled antioxidant supplementation to alleviate the problem. Motility of sperm obtained from n = 5 Large White boars housed in the dry tropics of Townsville, North Queensland, Australia was characterized by Computer-Assisted Sperm Analysis but did not differ between summer, winter or spring (total motility: 71.3 ± 8.1 vs. 90.2 ± 4.2 vs. 70.8 ± 5.5% ...
At 40% share, pork is the most widely eaten meat globally. As such, research efforts must improve... more At 40% share, pork is the most widely eaten meat globally. As such, research efforts must improve production and efficiency in the pig industry to meet growing demand. However, summer heat stress has a significant negative impact on pig fertility; causing embryonic death and decreased litter size that cost the industry millions in productivity losses. This problem is particularly prevalent in the tropics where ambient temperatures rise beyond the animal’s zone of thermal comfort. Boars are particularly vulnerable to the effects of heat stress due to their inefficient capacity to sweat; non-pendulous scrotum; and the high susceptibility of boar sperm to temperature shock. Moreover, due to limited endogenous antioxidant systems inherent in mammalian spermatozoa and the loss of cytosolic repair mechanisms during spermatogenesis, the DNA in these cells are particularly susceptible to oxidative damage. While a seemingly healthy looking sperm may swim and fertilize an oocyte normally, stu...
The use of frozen-thawed boar sperm still lags behind chilled boar semen in artificial inseminati... more The use of frozen-thawed boar sperm still lags behind chilled boar semen in artificial insemination (AI) operations despite its advantages [1]. Freezing however, may damage the structure and function of sperm, leading to reduced fertilization success. Moreover, glycerol, which is a critical cryoprotectant in most sperm freezing protocols, can be toxic to cells in high concentrations [2]; affecting sperm motility and acrosomal integrity. This study was conducted to determine the cryoprotective effect of glycerol on sperm DNA integrity and motility in frozen-thawed boar sperm.
Background: Summer infertility due to heat stress significantly affects the reproductive potentia... more Background: Summer infertility due to heat stress significantly affects the reproductive potential of pigs causing over $300 million per year in lost productivity to the US pig industry and billions worldwide. The boar's inefficient capacity to sweat; non-pendulous scrotum, and the high susceptibility of boar sperm to temperature shock appears to correlate with higher sperm DNA damage during summer. Heat stress-induced sperm DNA damage can result in early embryo loss, as demonstrated in mice. This study investigated whether supplementing boars with antioxidants during summer could improve boar sperm DNA integrity. Method: Motility of sperm obtained from n=5 Large White boars housed in the dry tropics of Townsville, Queensland, Australia were analysed using Computer-Assisted Sperm Analysis. Sperm DNA integrity during summer was compared without or after 42 and 84 days antioxidant supplementation, by Terminal deoxynucleotidyl transferase dUTP Nick-End Labelling and flow cytometry....
Introduction: While pork is the most widely eaten meat in the world, pig production is continuall... more Introduction: While pork is the most widely eaten meat in the world, pig production is continually threatened by changing climate conditions resulting in poor reproductive performance, particularly in the tropics. The boar's inefficient capacity to sweat; non-pendulous scrotum and high susceptibility of boar sperm to temperature shock makes this species particularly vulnerable to the effects of heat stress. While DNA-damaged sperm may fertilize normally, key genes involved in early embryo development may be severely affected inducing early embryo loss as shown in the mice. Our study demonstrates that tropical summer significantly increases DNA damage in populations of sperm within the ejaculate without necessarily affecting sperm motility. Moreover, supplementing boars with antioxidants during summer could potentially reduce the negative impact of heat stress on sperm DNA integrity. Materials and Methods: Five mature Large White boars were housed individually in open gable pens ...
Reproduction, Fertility and Development, 2018
Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particu... more Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particularly in the tropics, costing the industry millions in annual losses. The boar’s reduced capacity to sweat and non-pendulous scrotum, combined with the widespread use of European breeds in the tropics, makes this species particularly vulnerable to heat stress. Although heat stress is traditionally considered a sow problem, recent mouse studies demonstrate that heat stress-induced sperm DNA damage can result in arrested development and loss of early embryos. Our study investigated the impact of tropical summer heat stress on the quality and DNA integrity of boar sperm, and trialled antioxidant supplementation to alleviate the problem. Data, expressed as mean ± SEM, were analysed by one-way repeated-measures ANOVA with pairwise Bonferroni tests. Motility of sperm obtained from Large White boars (n = 5) housed in the dry tropics of Townsville, North Queensland, Australia, was characterised ...
Animal Production Science, 2017
Temperature is a crucial factor in mammalian spermatogenesis. The scrotum, pampiniform plexus, an... more Temperature is a crucial factor in mammalian spermatogenesis. The scrotum, pampiniform plexus, and cremaster and dartos muscles in mammals are specific adaptations to ensure sperm production in a regulated environment 4−6°C below internal body temperature. However, the limited endogenous antioxidant systems inherent in mammalian spermatozoa compounded by the loss of cytosolic repair mechanisms during spermatogenesis, make the DNA in these cells particularly vulnerable to oxidative damage. Boar sperm is likely to be more susceptible to the effects of heat stress and thus oxidative damage due to the relatively high unsaturated fatty acids in the plasma membrane, low antioxidant capacity in boar seminal plasma, and the boar’s non-pendulous scrotum. Heat stress has a significant negative impact on reproductive performance in piggeries, which manifests as summer infertility and results in productivity losses that amount to millions of dollars. This problem is particularly prevalent in tr...
Theriogenology, 2015
The sperm reservoir is formed when spermatozoa bind to the epithelium of the utero-tubal junction... more The sperm reservoir is formed when spermatozoa bind to the epithelium of the utero-tubal junction and caudal isthmus of the oviduct. It is an important mechanism that helps synchronize the meeting of gametes by regulating untimely capacitation and polyspermic fertilisation. This study investigated the influence of epididymal maturation and caudal fluid on the ability of spermatozoa to bind to oviduct epithelium using a model porcine oviduct explant assay. Spermatozoa from the rete testis, middle caput (E2-E3), middle corpus (E6) and cauda (E8) of Large White or Large White x Landrace boars at 10-14 months of age were diluted in modified Androhep solution and incubated with porcine oviduct explants. Results reported in this study support our hypothesis that testicular spermatozoa need to pass through the regions of the epididymis in order to acquire the ability to bind to the oviduct. There was a sequential increase in the number of spermatozoa that bound to 28 oviduct explants from the rete testis to caudal epididymis. Binding of caudal 29 spermatozoa to isthmic explants was the highest (15.0 ± 1.2 spermatozoa per 1.25 30 mm 2 ; mean ± standard error of the mean; P ≤ 0.05) and lowest by spermatozoa from the rete testis (2.0 ± 0.3 per 1.25 mm 2), and higher to isthmus from sows compared to gilts (35.8 ± 6.7 per 1.25 mm 2 vs. 14.8 ± 3.0 per 1.25 mm 2 ; P ≤ 0.05). Binding of ejaculated spermatozoa to porcine isthmus was higher than for caudal spermatozoa (26.3 ± 1.4 per 1.25 mm 2 vs. 15.0 ± 0.8 per 1.25 mm 2 ; P ≤ 0.05), and higher to 35 porcine than to bovine isthmus (26.3 ± 2.3 per 1.25 mm 2 vs. 18.8 ± 1.9 per 1.25 mm 2 ;