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Cryoinjury and protein changes are a consequence of cryopreservation and may have a negative impact on sperm quality regarding motility, viability and fertilizing ability. However, potential proteomic changes in rabbit semen throughout the cryopreservation process have never been previously investigated. The aim of the present study was to compare the whole proteome of fresh and cryopreserved rabbit semen (spermatozoa and extracellular fluid), to examine the effects of freeze-thawing on proteins changes in semen. Comparative analysis and identification of proteins was carried out using 2-dimensional difference in-gel electrophoresis coupled with a matrix-assisted laser desorption/ionization mass spectrometry. Proteomic raw data are available via ProteomeXchange with identifier PXD034832 for spermatozoa and PXD034853 for extracellular fluid. Respectively, 107 and 28 proteins differed in abundance in spermatozoa and extracellular fluid between fresh and frozen groups. Most of these proteins were involved in pathways related to energy metabolism and protein quality control under stress conditions, reproductive processes and mechanisms of cell death/survival regulation, resulting in a significant decrease of motility and viability of post-thawing rabbit sperm and its potential fertilizing ability. These results broaden the understanding of the effects of cryopreservation on rabbit semen and represent a new starting point for the development of improved freezing procedures., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)

This study was designed to optimize the semen freezing protocol of the native Mediterranean brown trout inhabiting the Molise rivers through two experiments: an in vitro analysis of the effects of two basic extenders combined with three cryoprotectants on post-thaw semen quality; and an in vivo test to assess the fertilization and hatching rate. Semen was diluted at a ratio of 1:3 in a freezing medium composed of a glucose extender (A) or mineral extender (B). Each basic component contained 10% dimethylsulfoxide, dimethylacetamide or methanol. The post-semen quality was evaluated considering motility, duration of motility, viability and DNA integrity. The basic extender and cryoprotectant were shown to have significant effects on these variables, and the best results were obtained using extender A or B combined with dimethylsulfoxide (P < 0.05). These freezing protocols were selected for fertilization trials in vivo. Fertilization and hatching rates were significantly higher in fresh semen. No significant differences were observed in frozen semen using extender A or B, although higher percentages of eyed eggs and hatching rates were recorded using extender A. According to our in vitro and in vivo results, the glucose-based extender and dimethylsulfoxide emerged as the best combination for an effective cryopreservation protocol for semen of this trout.

The aim of this study was to investigate the effect of initial cooling time at 5°C during semen cryopreservation on post-thaw quality and reproductive performance of rabbit semen. Pooled semen samples (n = 6) were divided into two subsamples and cooled at 5°C for 45 or 90 min. After cooling, the semen samples were diluted to a ratio of 1:1 (v:v) with a freezing extender composed of Tris-citrate-glucose (TCG) containing 16% of dimethylsulfoxide and 0.1 mol/L sucrose. The semen was subsequently loaded in 0.25 ml straws, equilibrated at 5°C and frozen in liquid nitrogen vapor. After thawing, sperm motility, viability, osmotic resistance, acrosome and DNA integrity were assessed. Our results indicate that the longer cooling time, that is, 90 min before cryopreservation significantly improves sperm post-thaw viability, motility and fertility. In fact, reproductive performances obtained with semen frozen after a 90 min cooling time were similar to those produced by fresh semen insemination. Hence, the present research provides an effective freezing protocol for rabbit semen that will allow for the creation of a sperm cryobank for the conservation of Italian rabbit genetic resources, as well as the use of frozen semen doses in commercial farms., (© 2018 Japanese Society of Animal Science.)

Simple Summary: The conservation of local chicken breeds is globally considered because of their interesting characteristics, such as their tolerance to heat stress, resistance to diseases and capacity to survive in severe environments. In recent years, conservation programs of native chicken breeds have been developed in Italy, and this work has focused on Bionda Piemontese, Bianca di Saluzzo and Pepoi, the first two of which are catalogued as endangered and the third as a 'critically maintained' breed. Semen cryopreservation is the only method that is currently feasible for the ex situ management of genetic diversity in birds, and poultry sperm shows a greater susceptibility during the freezing/thawing process due to its unique features. Therefore, the choice of the most suitable rooster sperm donor is fundamental in the establishment of a semen cryobank. The present study aims to analyze the efficiency of bird and semen management required for the implementation of the Italian Semen Cryobank of Autochthonous Chicken and Turkey Breeds created with the "TuBAvI" project. Our results suggest that male donors need to be selected based on the quality of fresh ejaculates, regardless of sperm outcome after freezing/thawing, in order to identify individuals who can ensure the survival of a breed with regard to increased fertilizing capacity. Native breed conservation is an important component of poultry biodiversity. The aim of this work is to describe different steps that lead to donor selection for the implementation of the Italian Semen Cryobank of Autochthonous Chicken and Turkey Breeds. The variability within and between breeds was evaluated, and the stored semen reproductive capacity was in vivo tested using artificial insemination. Semen from Bionda Piemontese, Bianca di Saluzzo and Pepoi roosters was collected and processed. Concentration, volume, sperm membrane integrity, total motile sperm, progressive motile sperm and kinetic parameters were analyzed; sperm parameters accounting for bird variability were used to select male donors. Fresh semen quality parameters measured in donor ejaculates showed significant differences between breeds; no differences were found after cryopreservation. Variability in the fertilizing ability of cryopreserved semen was found within a breed (5–16%) and between birds within a breed (BP = 3–7%; BS = 7–31%; PP = 6–22%); only sperm quality parameters measured in fresh ejaculates, not frozen/thawed, may be associated with in vivo fertility results. In conclusion, sperm concentration and progressive motility were successfully used as selection parameters to identify chicken male donors with improved sperm quality for sperm cryobanking. However, new reliable sperm markers to predict cryopreserved semen's fertilizing ability are required. [ABSTRACT FROM AUTHOR]

Simple Summary: In the rabbit species, the use of frozen semen could play a twofold role; on the one hand, it could bring many benefits to commercial breeding operations that rely on artificial insemination, and on the other hand, it would enable the conservation of biodiversity through the establishment of semen cryobanks. One of the less explored aspects of cryopreserving rabbit semen involves establishing the ideal sperm concentration in straws. Achieving this goal is crucial for minimizing the variability in outcomes and accurately determining the number of sperm delivered during artificial insemination procedures. This study sought to determine the ideal sperm concentration in straws for cryopreserving rabbit semen, with the broader goal of improving and standardizing the freezing protocol developed by our research group over the past decade. Our study provided a comprehensive analysis of how different sperm concentrations within straws (ranging from 15 to 75 million sperm) influenced the critical stages of the cryopreservation process, starting from initial dilution with the extender, through to cooling and equilibration, and culminating in the thawing phase. This investigation shed light on the role of the sperm concentration when determining the overall success of rabbit semen cryopreservation. This study aimed to investigate the impact of sperm concentrations on the in vitro quality of cryopreserved rabbit semen. The semen pools (n = 8, from 80 donors) were split into five aliquots with final sperm concentrations of 15, 25, 35, 55, and 75 × 106 per straw. The sperm motility parameters (CASA system) and membrane integrity (flow cytometric analysis) were both evaluated at various stages of the cryopreservation process: fresh semen dilution, cooling, equilibration, and immediately after and 30 min post-thawing. The results indicated the significant influence of the sperm concentration on the total motility (TM) and progressive motility (PM), with a consistent decline in all sperm variables over the time points. Notably, the semen with a final concentration of 15 × 106 exhibited a higher TM and PM after cooling and equilibration. The post-thawing quality (TM, PM) was higher (p < 0.05) in the mid-range sperm concentrations of 25 × 106 (49.9% and 19.7%) and 35 × 106 (46.2% and 19.7%) compared to the other concentrations. This study demonstrated that the sperm concentration per straw played a significant role in specific phases of the cryopreservation process. These findings contribute valuable insights for refining and standardizing the cryopreservation protocol for rabbit semen, emphasizing the importance of the sperm concentration. [ABSTRACT FROM AUTHOR]

Simple Summary: In the context of the "Life—Nat.Sal.Mo" project, obtaining an effective semen cryopreservation protocol was an important milestone that allowed the implementation of the first European cryobank of native Mediterranean brown trout (S. cettii) inhabiting Molise rivers (Italy). The main use of our semen cryobank is represented by its practical application in artificial reproduction practices aimed at maximizing the genetic variability of the offspring and reducing the genetic introgression in the native trout populations in the project area. Thus, the choice of the most suitable activation/fertilization medium represents the last key step in the development of artificial reproduction protocols using cryopreserved semen. Therefore, the aim of the present study was to investigate the effect of ovarian fluid as a natural activation media of spermatozoa on the post-thaw sperm swimming performance of Mediterranean trout, comparing it with D-532 and a mixed solution of 50% D-532 and 50% ovarian fluid. Our results suggest that the presence of ovarian fluid alone or in combination with D-532 in the artificial microenvironment of reproduction represents a key factor to increase the success of fertilization when the frozen semen of Mediterranean brown trout is used. D-532 fertilization solution is generally used to replace the water or ovarian fluid during artificial reproductive practices in salmonids due to its ability to boost sperm motility and increase fertilization rates compared with natural activation media. However, the maintenance of ovarian fluid in a reproductive microenvironment gives it the advantage of protecting the eggs from potential harmful factors from the external environment and simplifying the field operations related to its removal when D-532 is used alone. In light of this, the aim of the present study was to investigate in vitro, for the first time, the effect of ovarian fluid (OF 100%) on post-thaw sperm swimming performance of Mediterranean trout, comparing it with D-532 and a mixed solution of 50% D-532 and 50% ovarian fluid (OF 50%). The percentage of motile spermatozoa and movement duration was significantly increased in OF 100% and OF 50% compared with D-532. Sperm velocity was higher in D-532, but significant differences were recorded only with OF 100%. In conclusion, these results suggest that the presence of ovarian fluid alone or in combination with D-532 in an artificial microenvironment of reproduction represents a key factor in potentially increasing fertilization success when the frozen semen of Mediterranean brown trout is used. [ABSTRACT FROM AUTHOR]

Simple Summary: Semen cryobanking is a valuable tool for preserving the genetic resources of a wide range of species, providing the opportunituy to preserve representative samples and reconstruct the population or diversity. However, in avian species, the freezing–thawing process results in a sharp reduction in sperm quality and consequently fertility. This is mainly due to the lack of knowledge about the molecular basis of the cryopreservation process, especially in more sensitive species such as turkey. Thus, in this study, we took advantage of NMR technology to assess the changes in metabolic profile occurring in turkey sperm cryopreservation, which were correlated with sperm qualitative parameters measured in both fresh and frozen–thawed samples. Hence, the results reported here depict a clearer scenario about the changes in the levels of amino acids, other water-soluble compounds, and lipids resulting from the freezing–thawing process. Moreover, a wide discussion about the possible pathway affected by cryopreservation is provided. Therefore, this study allows us to: (i) identify biological markers related to the sperm freezability of male turkey donators; (ii) suggest a supplementation of specific metabolites in the diet or in the freezing medium in order to obtain spermatozoa abler to withstand the freezing process. Semen cryopreservation represents the main tool for preservation of biodiversity; however, in avian species, the freezing–thawing process results in a sharp reduction in sperm quality and consequently fertility. Thus, to gain a first insight into the molecular basis of the cryopreservation of turkey sperm, the NMR-assessed metabolite profiles of fresh and frozen–thawed samples were herein investigated and compared with sperm qualitative parameters. Cryopreservation decreased the sperm viability, mobility, and osmotic tolerance of frozen–thawed samples. This decrease in sperm quality was associated with the variation in the levels of some metabolites in both aqueous and lipid sperm extracts, as investigated by NMR analysis. Higher amounts of the amino acids Ala, Ile, Leu, Phe, Tyr, and Val were found in fresh than in frozen–thawed sperm; on the contrary, Gly content increased after cryopreservation. A positive correlation (p < 0.01) between the amino acid levels and all qualitative parameters was found, except in the case of Gly, the levels of which were negatively correlated (p < 0.01) with sperm quality. Other water-soluble compounds, namely formate, lactate, AMP, creatine, and carnitine, turned out to be present at higher concentrations in fresh sperm, whereas cryopreserved samples showed increased levels of citrate and acetyl-carnitine. Frozen–thawed sperm also showed decreases in cholesterol and polyunsaturated fatty acids, whereas saturated fatty acids were found to be higher in cryopreserved than in fresh sperm. Interestingly, lactate, carnitine (p < 0.01), AMP, creatine, cholesterol, and phosphatidylcholine (p < 0.05) levels were positively correlated with all sperm quality parameters, whereas citrate (p < 0.01), fumarate, acetyl-carnitine, and saturated fatty acids (p < 0.05) showed negative correlations. A detailed discussion aimed at explaining these correlations in the sperm cell context is provided, returning a clearer scenario of metabolic changes occurring in turkey sperm cryopreservation. [ABSTRACT FROM AUTHOR]

The creation of genetic resource cryobanks provides a crucial link between in situ and ex situ techniques to improve the efficiency of conservation programs. Aim of the present review is to describe all the activities developed for the implementation of the first Italian Semen Cryobank of Autochthonous Chicken and Turkey Breeds. These activities can be classified into three main topics: (1) identification of species-specific semen freezing/thawing reference procedures; (2) drafting Standard Operative Procedures (SOP) for the implementation of the semen cryobank; (3) storage of semen doses from Italian chicken and turkey breeds to establish the cryobank. Several trials have been developed to identify a specie-specific semen cryopreservation protocol for chickens and turkeys. The major results are reviewed and a final reference protocol described. Taking into consideration the FAO guidelines for cryoconservation of animal genetic resources, SOP were drafted with the aim to provide technical guidance and logistical support on the choice of priority breeds, selection of birds for semen production, infrastructures and storage sites, birds and semen management, cryopreservation process and doses traceability. Lastly, the Italian Semen Cryobank was created. A total of 112 semen doses from 22 cockerels of three breeds, and 74 doses from 12 turkey males of three breeds were stored in the Cryobank. Breed specific semen quality parameters assessed before and after cryopreservation are reported. The described activities provide information and tools useful for the implementation of semen cryobanking in avian species and might be transferred also to other species after appropriate adaptations. Implementation of the first Italian Semen Cryobank of Autochthonous Chicken and Turkey Breeds Drafting Standard Operative Procedures provides technical guidance and logistical support on the design and establishment of the cryobank Semen cryobank is a precious genetic reservoir and could be useful to safeguard genetic variability in small population in vivo conserved [ABSTRACT FROM AUTHOR]

This study has been designed to optimize the semen freezing protocol in rabbits, in this regard we compared a Tris-citrate-glucose (TCG) extender with a commercial one (Cortalap®), that to the best of our knowledge has never been used up to now on the in vitro freezability and fertilizing ability of cryopreserved rabbit semen. Two different inseminating semen doses were considered. Five pooled semen samples were divided into two subsamples and each of them were diluted to a ratio 1:1 (v:v) with a freezing extender composed of TCG or Cortalap® containing 16% of dimethylsulfoxide and 0.1 mol/L of sucrose. The extended semen was filled into 0.25 mL plastic straws and frozen above a liquid nitrogen surface. After thawing (50°C/10 seconds) we determined sperm motility, viability, membrane functionality, acrosome and DNA integrity. Our results showed that the Cortalap® extender significantly improved the in vitro post-thaw sperm quality, in comparison to TCG. When we compared the extenders in vivo, no significant differences in the reproductive performances were observed independently by inseminating doses used. In this study we demonstrated that Cortalap® extender can be used as an alternative to TCG. Thus, the Cortalap® being a ready to use extender, implies a reduction of time, mistakes and microbial contaminations during its preparation. This discovery results as significant because it provides beyond an important contribution to the creation of the first Italian semen cryobank of rabbit breeds and also for livestock rabbit farms based on artificial insemination (AI) program. [ABSTRACT FROM AUTHOR]

Metabolic profile of fresh turkey spermatozoa at three different reproductive period ages, namely 32, 44 and 56 weeks, was monitored by Nuclear Magnetic Resonance (NMR) spectroscopy and correlated to sperm quality parameters. The age-related decrease in sperm quality as indicated by reduction of sperm concentration, sperm mobility and osmotic tolerance was associated to variation in the level of specific water-soluble and liposoluble metabolites. In particular, the highest levels of isoleucine, phenylalanine, leucine, tyrosine and valine were found at 32 weeks of age, whereas aspartate, lactate, creatine, carnitine, acetylcarnitine levels increased during the ageing. Lipid composition also changed during the ageing: diunsaturated fatty acids level increased from 32 to 56 weeks of age, whereas a reduction of polyunsaturated fatty acids content was observed at 56 weeks. The untargeted approach attempts to give a wider picture of metabolic changes occurring in ageing suggesting that the reduction of sperm quality could be due to a progressive deficiency in mitochondrial energy producing systems, as also prompted by the negative correlation found between sperm mobility and the increase in certain mitochondrial metabolites. [ABSTRACT FROM AUTHOR]

This review updates the current state of technologies available for turkey semen storage (hypothermic- liquid storage and cryopreservation), with special attention paid to cryopreservation. Liquid semen can be stored for up to 24 or 48 h at temperatures around 5°C, while cryopreservation allows long-term storage at -196°C. The possibility of using frozen turkey semen for artificial insemination (AI) would have practical benefits for turkey production. Reported fertility rates in response to AI using frozen/thawed semen range from 15.8 to 84.3%. Unsatisfactory fertility may be attributed to an inability of turkey spermatozoa to successfully survive the freezing/thawing process, and this, along with the high variability observed, makes this technique unacceptable for commercial breeding programs. There is therefore a need to standardize the whole freezing and thawing process to improve the post-thaw quality of turkey semen and minimize variability in results. Finding an efficient freezing protocol for turkey semen will allow for the creation of a sperm cryobank, improving current prospects for the commercial use of frozen turkey semen and also for the long-term conservation of the genetic diversity of this bird. [ABSTRACT FROM AUTHOR]

This study was designed to compare Cortalap® extender with tris-citric acid-glucose (TCG), Lepus® and Merk III®, to assess the in vitro preservability of rabbit spermatozoa stored for 72 h at 5°C. The best extender identified in vitro was then compared with fresh semen to determine fertility and prolificacy rates in vivo. Eight semen pools were split into four subsamples and each of them was diluted to a ratio of 1:10 (volume:volume) with four different extenders (Lepus®, Cortalap®, TCG and Merk III®) and stored at 5°C for 72 h. Sperm motility, viability, sperm membrane and acrosome integrity were evaluated in both fresh and chilled semen at 4, 24, 48 and 72 h of storage. The results showed that Cortalap® was the best extender to preserve the quality of rabbit semen in vitro over 72 h in comparison with the other extenders (P<0.05). Then, Cortalap® was used for an artificial insemination (AI) trial to be compared with fresh semen. Two groups of does (n=30 each) were inseminated with fresh and chilled semen. The fertility and prolificacy rates for the does inseminated with chilled semen were significantly lower compared with those inseminated with fresh semen (P<0.05). In conclusion, although Cortalap® proved to be the best extender to preserve semen quality in vitro after 72 h at 5°C, the in vivo results showed that its use is not recommended in AI programmes. [ABSTRACT FROM AUTHOR]

Simple Summary: Achieving an effective freezing protocol, that is able to preserve the fertilizing ability of turkey semen, is a key aim for the establishment of the first national semen cryobank of autochthonous chicken and turkey breeds within our national project (Tutela della biodiversità nelle razze avicole italiane—TuBAvI). In this regard, we have performed different studies in order to define the best conditions for cryopreservation of turkey semen; namely, we identified an effective freezing protocol which is based on the use of dimethylsulfoxide as a permeant cryoprotectant (CPA) combined with Ficoll as a non-permeant CPA. Here, our purpose was to test this protocol in vivo, by evaluating the effect of two extenders and three inseminating doses. The good fertility and hatching rates achieved here are promising for future studies, in which our cryopreservation protocol will be tested on Italian autochthonous turkey breeds and also to the advantages offered by the extensive use of frozen semen in the turkey breeding industry. This study was designed to test the fertilizing ability of cryopreserved turkey semen, and here, two experiments were performed: an in vitro analysis to assess the effects of Tselutin and Lake diluents and an in vivo test to determine the fertility and hatching rates by also studying the feat of three insemination doses (250, 400 and 600 × 106 sperm/hen). Pooled semen samples were diluted with Tselutin or Lake extender which contained 20% of dimethylsulfoxide and 1 mM of Ficoll at final sperm concentration of 3 × 109 sperm/mL. Thereafter, semen was packaged into straws and frozen on liquid nitrogen. The post-thaw sperm quality was evaluated considering motility (computer-aided sperm analysis—CASA system) and membrane integrity (flow cytometry). Significantly higher values of progressive motility and some kinetic parameters in semen frozen with Lake were found. When we compared the extenders in vivo, no significant effects were detected, whilst sperm concentration significantly affected both fertility and hatching rates, with the best results obtained with the sperm concentration of 400 × 106 sperm/hen. From the results obtained, it emerged that the extender type only affected sperm motility characteristics, not the fertilizing ability of frozen-thawed semen, while inseminating dose markedly affected fertility and hatching rates. [ABSTRACT FROM AUTHOR]

Simple Summary: The most adopted biotechnology for the conservation of genetic resources in avian species is semen cryopreservation. Therefore, the identification of a reference cryopreservation procedure represents a key point for ensuring the long-term conservation of genetic diversity in birds, through the implementation of a semen cryobank. In this study, our goal was to discover an effective freezing protocol for Meleagris gallopavo in order to realize the first Italian semen cryobank of autochthonous chicken and turkey breeds within our project (TuBAvI). For this purpose, we investigated the effects of three non-permeant cryoprotectants (sucrose, trehalose, and Ficoll) and two dilution rates (1:2 and 1:4) on the in vitro cryosurvivability of turkey spermatozoa. After thawing, the best semen quality was found in semen frozen in the presence of Ficoll and diluted at a final rate of 1:4. This paper provides encouraging results, however further studies are programmed to standardize the semen cryopreservation protocol. The present study aimed to find an effective cryopreservation protocol for turkey semen through the combined use of dimethylsulfoxide (DMSO) and three non-permeant cryoprotectants (NP-CPAs), sucrose, trehalose, and Ficoll 70. In addition, the action of two dilution rates (1:2 and 1:4) were also investigated. Semen was processed according to two final dilution rates and the following treatments: Tselutin extender (TE)/DMSO (control), TE/DMSO + sucrose or trehalose 50, 100, 200, or 400 mM, and TE/DMSO + Ficoll 0.5, 0.75, 1, or 1.5 mM. In total 26 different combinations treatments were achieved. The diluted semen was filled up into straws and frozen on liquid nitrogen vapor. The post-thawing sperm quality was assessed by analyzing motility, membrane integrity, osmotic resistance, and DNA integrity. The results obtained revealed a significant effect of NP-CPA concentration on total and progressive motility, on most of the kinetic parameters, on membrane integrity and DNA integrity, while the post-thaw quality was less affected by dilution rate. The highest post-thaw quality for all sperm quality parameters assessed except curvilinear velocity (VCL) and DNA integrity were found in semen frozen with 1 mM Ficoll/1:4 (p < 0.05). Our findings provide an important contribution for the identification of a reference procedure for turkey semen cryopreservation, in order to create the first national avian semen cryobank. [ABSTRACT FROM AUTHOR]

Simple Summary: The sperm cryobank is an effective strategy for protecting the biodiversity of the local brown trout population. Thus, the aim of the present work was to test, for the first time, the effectiveness of a semen cryopreservation protocol developed for cultivated salmonid fish on wild trout inhabiting the Molise rivers. Moreover, the effects of two different thawing rates (40°C/5 s and 10°C/30 s) were evaluated in vitro and in vivo. In addition, different sperm-to-egg ratios (6 × 105:1, 4.5 ×105:1 and 3 × 105:1) were also investigated in vivo in order to find an effective freezing protocol useful for the creation of the first European semen cryobank for the Mediterranean brown trout (S. macrostigma = S. cettii). From results obtained in vitro 40 °C turned out to be the best thawing rate, which in combination with a sperm-to-egg ratio of 4.5 × 105:1 was, in vivo, the highest fertilization rate. The important results obtained in the present work corroborated the remarkable validity and effectiveness of the freezing protocol used in this study on the native trout populations from Molise. The aim of our study was to test the effectiveness of a simple semen cryopreservation procedure, developed for cultivated salmonid, on the wild salmonid of the Mediterranean area and to evaluate the effect of different thawing rates and sperm-to-egg ratios. The semen of five individual males was diluted into a final extender concentration of 0.15 M glucose and 7.5% methanol and loaded into 0.25 mL plastic straws, and a final sperm concentration of 3.0 × 109 sperm/mL was obtained. After equilibration, the straws were frozen by exposure to liquid nitrogen vapor at 3 cm above the liquid nitrogen level for 5 min. The semen was thawed at 40 °C/5 s or 10 °C/30 s. The sperm cryosurvival was evaluated by examining in vitro the sperm motility parameters using the CASA system, followed by fertilization trials in vivo, using three different sperm-to-egg ratios 6 × 105, 4.5 × 105 and 3 × 105:1. The applied cryopreservation procedure resulted in remarkably high (85.6%) post-thaw sperm total motility, when the semen was thawed at 40 °C/5 s, whilst the highest fertilization rate (53.1%) was recorded for a sperm-to-egg ratio of 4.5 × 105:1. According to these outcomes, the cryopreservation procedure that was tested turned out to be effective for the wild population of Mediterranean brown trout and practical for the creation of the first European semen cryobank foreseen as part of our "LIFE" Nat.Sal.Mo. project. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the effect of two permeant-cryoprotectants, dimethylacetamide (DMA) and N-methylacetamide (NMA) used at different concentrations (0%, 2%, 4%, 6%) on the quality and fertility of post-thaw rooster semen. Ejaculates were processed in 7 treatments: Lake pre-freezing+0.1 M trehalose (LPF-T) (control treatment), LPF-T+2% DMA, LPF-T+4% DMA, LPF-T+6% DMA, LPF-T+2% NMA, LPF-T+4% NMA, LPF-T+6% NMA. Sperm quality [sperm membrane integrity (SMI), motility and kinetic parameters] was assessed before and after cryopreservation. Fertility and embryo viability were recorded. Increasing both DMA and NMA concentration from 2 to 6% improved SMI, total motile sperm, progressive motile sperm (PMS), VCL, VSL and VAP values. PMS recovery rates were significantly the highest in 6% DMA, 4% NMA and 6% NMA treatments. Semen cryopreserved with DMA produced the best fertility and embryo viability at 6%; progressive lower values were recorded at lower concentrations, with no viable embryos at 2%. Semen cryopreserved with NMA showed the best fertility values at 2% and lower values were recorded at higher concentrations; live embryos were found in all NMA treatments. Finally, NMA and DMA showed a similar positive concentration dependent effect of the quality of cryopreserved semen. NMA, not DMA, provided the highest fertility and embryo viability values at the lowest 2%. Therefore, the use of NMA is recommended in order to reduce the cryoprotectant concentration, with a concomitant reduction in the risk of toxicity, providing at the same time the adequate cryoprotective action to obtain viable embryos after artificial insemination of cryopreserved chicken semen. • Lower cryoprotectant concentrations in chicken sperm cryopreservation. • Evaluation of chicken sperm motility parameters. • Dimethylacetamide and N-methylacetamide in freezing poultry semen. • N-methylacetamide in synergy with Trehalose in frozen chicken sperm. • Live embryos obtained using rooster semen cryopreserved with N-methylacetamide. [ABSTRACT FROM AUTHOR]