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Boar sperm quality is less during the summer as a result of the different photoperiod or ambient temperatures as compared with the winter. The present study was conducted to elucidate possible variations in proteomic profiles of boar spermatozoa collected during the summer and winter. Effects of season on sperm viability, total motility, progressive motility, acrosome status, mitochondrial membrane potential and plasma membrane lipid organization were also analyzed. Only sperm viability and mitochondrial membrane potential were less during the summer (P <  0.05). Spermatozoa were processed and evaluated using the nano LC-MS/MS QTof procedures. A total of 1028 characterized proteins were identified in sperm collected during both seasons of the year (False Discovery Rate < 0.01) and, among the total, 85 proteins differed in sperm collected in the winter and summer, with there being a lesser abundance of these proteins when there were ejaculate collections during the summer (q-value ≤ 0.05). The results from enrichment assessments for these protein networks utilizing UniProtKB procedures for determining reproductive processes indicates there were 23 proteins that were less abundant in the summer than winter. These proteins have essential functions in spermatogenesis, sperm motility, acrosome reaction and fertilization. These results are the first where there was ascertaining of proteomic differences in boar spermatozoa collected in the summer and winter. These results might help to explain the decreased sperm quality and prolificity when semen of boars is used for artificial insemination that is collected during the season of the year when ambient temperatures are relatively greater., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Frozen-thawed boar sperm have less motility and fertility capacity in comparison to fresh sperm. Glycogen Synthase Kinase 3 (GSK3) contributes to sperm motility in fresh semen. In addition, GSK3 inhibition in boar spermatozoa in fresh semen improves motility variables. The role of GSK3 on boar cryopreserved sperm, however, is still unknown. The hypothesis in the present study was that GSK3 pathway inhibition by alsterpaullone (AST) could result in enhancement of the quality of sperm afer cryopreservation. Two different strategies were evaluated: i) AST supplementation to the freezing medium (AST + Cryo); ii) AST supplementation after sperm thawing (AST + Thaw). Sperm motility was evaluated using the CASA system and different sperm quality variables were evaluated using flow cytometry, as well as amount of GSK3 phosphorylation of thawed spermatozoa after 30 and 90 min incubation at 38.5 °C. Results indicate that AST supplementation had detrimental effects on sperm viability (live spermatozoa) and mitochondrial membrane potential when it was added after thawing (P <  0.05) The AST supplementation after thawing, however, had a protective effect on plasma membrane lipid disorganization (P <  0.05). The percentage of motile spermatozoa was not modified by AST supplementation. Nonetheless, after 30 min post-thawing, STR and LIN variables (related to straightness of the movement) as well as the percentage of rapid lineal spermatozoa were increased with both AST supplementation protocols. The GSK3α phosphorylation was not modified through the incubation time in boar thawed sperm. In summary, results do not support the idea of adding AST to the cryopreservation/thawing medium to improve boar sperm quality after cryopreservation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The aim of this study was to determine the effect of lactation length and treatment with gonadotrophins at weaning on reproductive performance of primiparous sows. After 3 wk of lactation, primiparous sows were either weaned (W3; n=273) or received a 7-d-old foster litter for a further 14 d of suckling (W5; n=199). At final weaning (3 wk or 5 wk lactation) sows were randomly assigned to receive an injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600(®); W3 + P; n=108 and W5 + P; n=96) or no injection (W3; n=165 and W5; n=103). Sows were inseminated at first observed estrus after final weaning and 24h later. The proportion of sows showing estrus by 6 d post-weaning was greater (P<0.01) for W3+P (86%) compared to W3 (64%), however, there was not a difference (P=0.13) for W5 + P (79.4%) compared to W5 (69.1%). There was no effect of either lactation length or gonadotrophin treatment on farrowing rates or on the proportion of sows culled before breeding. Total born litter size was smaller (P=0.05) for W3 + P (11.7 ± 0.4) compared to W3 (12.6 ± 0.3). However, sows that lactated for 35 d had larger litters than sows that lactated for 21 d regardless of gonadotrophin treatment (14 ± 0.5 and 14.5 ± 0.4 for W5+P and W5, respectively; P<0.001). These data indicate that for primiparous sows, a longer lactation improves total born litter size at their next farrowing. Gonadotrophin treatment is useful in shortening the weaning to estrus interval but subsequent total born litter size may be negatively affected., (Copyright © 2014 Elsevier B.V. All rights reserved.)