Shortened daily photoperiod during the non-breeding season can improve the reproductive performance of camel bulls (Camelus dromedarius)

Kinematic and Morphometric Assessment of Fresh Semen, before, during and after Mating Period in Brahman Bulls

The objective of the present study was to determine the effects that the reproductive season has on the motility, kinematics, morphology, and sperm morphometry of Brahman bulls evaluated with a commercial CASA system. The experiment was carried out at the Costa Rica Institute of Technology from March to August 2021. A total of eight Brahman bulls were used. A total of 28 ejaculates were collected in the pre-mating period (PMP), during it (DMP), and after it (AMP) using an electroejaculator. The sperm concentration was measured with the Accuread photometer. The motility was measured using a Spermtrack® counting chamber. The analyses were performed with the CASA-Mot ISAS®v1 system. The morphology was analyzed using a microscope with a negative phase contrast objective. Morphometry was evaluated with the CASA-Morph. The sperm concentration did not present differences between the PMP and AMP; however, it was significantly higher than DMP (p > 0.05). Regarding the progressiveness variables, linearity on forward progression (LIN), straightness (STR), and wobble (WOB) were higher (p < 0.05) DMP. A kinematic principal component analysis grouped all the variables into three factors and an effect on the reproductive period was found (p < 0.05) in the parameters of the head and middle part of the sperm, such as width and perimeter, which were greater in the PMP. The length of the sperm head in the PMP and DMP did not show differences; however, both were larger (p < 0.05) than AMP. The insertion distance of the middle piece of the sperm was significantly greater than DMP. Finally, the PMP contained cells with a larger insertion angle (p < 0.05) than AMP. These findings are important to understand the implications of reproductive status on sperm quality and to consider them in andrological evaluations.

Effect of advancing the breeding season on reproductive performance of dromedary camels

This study examines the effect of advancing the breeding season on the reproductive performance of dromedary camels under an intensive management system. Using a synchronization protocol, timed natural mating in female camels was carried out either in September (2 months ahead of the natural breeding season, n = 182) or December (peak breeding season, n = 115). The ovarian responses (size of the dominant follicle at the time of mating and ovulation), pregnancy rate, and pregnancy losses were evaluated using ultrasonography. Blood samples were collected after mating to assess progesterone concentrations by RIA. The libido of male camels (n = 13) was evaluated objectively. Results showed that the percentage of female camels with an optimal sized follicle (11-17 mm) for breeding at the time of mating was lower in September compared to December (81.9 vs 91.3%, P = 0.03). The libido of male camels was lower in September than in December (P <0.001). The ovulation rate (86.3 vs 93.9%, P = 0.04), size of the ovulated follicle (12.7 ± 0.1 vs 13.7 ± 0.2 mm, P <0.001), pregnancy rates on Day 14 (47.8 vs 72.2%, P <0.001) and Day 90 (38.5 vs 60.9%, P <0.001) after mating was lower in September compared to December. However, pregnancy loss was not affected between months (15.7 vs 19.5%, P = 0.3). Among pregnant camels, the progesterone concentrations on Days 6, 8, 10, 12 and 14 after mating were lower in September as compared to December (P <0.001). In non-pregnant camels, the progesterone concentrations on Days 6, 8 and 10 after mating were also lower in September as compared to December (P <0.001). In conclusion, advancing the breeding season by two months, significantly affects the reproductive performance of dromedary camels, yet, acceptable pregnancy rates can be achieved.

Effects of vitamin C, vitamin E, selenium, zinc, or their nanoparticles on camel epididymal spermatozoa stored at 4 °C

This study determined the effects of antioxidant supplementation and storage time at cool temperatures on the characteristics of epididymal camel spermatozoa. Camel testes were collected at the abattoir after animal slaughtering and kept at 4 °C during transportation and until processing (max 6 h). Spermatozoa were retrieved and diluted with SHOTOR extender, split in aliquots, supplemented with the following antioxidants: 200 μm/mL vitamin E, 1.0 g/L vitamin C, 1 μg/mL selenium nanoparticles, 50 μg/mL zinc nanoparticles, 2 μg/mL sodium selenite, and 100 μg/mL zinc sulfate, and stored at 4 °C for 2, 48, 96, and 144 h. The storage time significantly affected (P < 0.05) the sperms' motility and livability, the sperms' membrane integrity, and the percentages of cytoplasmic droplets as well as the percentage of morphologically normal spermatozoa. Epididymal sperm characteristics (progressive motility, livability, membrane integrity, and abnormalities) were significantly improved (P < 0.05) when the spermatozoa were diluted with antioxidants as compared with the control group, and the best additives were identified as nano-selenium, sodium selenite, nano-zinc, and zinc sulfate. In conclusion, adding nano-sized minerals or inorganic trace elements and vitamins maintained the progressive motility, livability, and membrane integrity, and decreased abnormalities and cytoplasmic droplet percentages of epididymal camel spermatozoa stored at 4 °C up to 144 h.

Housing Management of Male Dromedaries during the Rut Season: Effects of Social Contact between Males and Movement Control on Sexual Behavior, Blood Metabolites and Hormonal Balance

Simple Summary

The effect of different housing management systems on the behavior, metabolites and hormonal balance in male dromedaries during the rutting season was evaluated. Male dromedaries that were housed in groups and allowed to walk around had significantly higher frequencies of ruminating, standing, walking and sexual-related behaviors than those housed individually or tied. Movement control had significant effects on blood serum metabolites and hormone concentrations. Fenced and exercised male dromedaries had higher (p < 0.05) concentrations of blood serum transaminases, free radicals, glucose, cholesterol and testosterone and lower (p < 0.05) concentrations of cortisol and triiodothyronine (T3) than tied male dromedaries. Animal social interaction is of particular importance for maintaining physical; psychological and sexual behaviors. Allowing walking-around exercise for captive animals improves their metabolic status and decreases captive stress effects. Housing systems that guarantee social interaction and physical activity are being the most suitable housing management systems for male dromedaries during the rutting season.

Abstract

The current study aimed to evaluate the effect of different housing management systems on behavior, blood metabolites and hormonal balance in male dromedaries during the rutting season. Forty-eight adult male dromedaries were stratified in a two by three factorial experiment design, testing effects of social contact (single and group) and movement control (tied, fenced and exercise). During a ten-week experimental period, male dromedaries were filmed weekly for 20 min three times per day to evaluate their behaviors. Blood samples were collected and analyzed for serum metabolites and hormones. Both animal social contact and movement control significantly affected maintenance, posture and sexual behaviors. Male dromedaries housed in groups expressed higher frequencies of sexual desire-related behaviors (teeth grinding, open legs, tail flapping, dulla “soft palate exteriorization”, blathering and urination) than those individually housed. Animal movement control significantly affected sexual behavior; fenced and exercised male dromedaries expressed higher frequencies of sexual desire-related behaviors than tied ones. Male dromedaries housed in groups and allowed to walk around had significantly higher frequencies of ruminating, standing, walking and sexual-related behaviors than those housed individually or tied. Movement control had significant effects on blood serum metabolites and hormone concentrations. Fenced and exercised male dromedaries had higher (p < 0.05) concentrations of blood serum transaminases, free radicals, glucose, cholesterol and testosterone (2.91 and 2.09 ng/mL, respectively) and lower (p < 0.05) concentrations of cortisol (44.12 and 53.52 nmol/L, respectively) and triiodothyronine (1.68 and 1.91 ng/mL, respectively) than tied male dromedaries. In conclusion, animal social interaction is of particular importance for maintaining physical, psychological and sexual behaviors. Allowing walking-around exercise for captive animals improves their metabolic status and decreases captive stress effects. Housing systems that guarantee social interaction and physical activity are the most suitable housing management systems for captive male dromedaries during the rutting season.

Dromedary camel: A model of heat resistant livestock animal

Camels are highly adapted to harsh environments. The dromedary camel is adapted to a wide range of arid and semi-arid conditions. The aim of the present paper is to review some of the key adaptation characteristics of the dromedary and how they affect reproductive patterns. Special attention is given to the reproductive seasonality and interaction between lactation and reproduction. Adaptive mechanisms are described including some of the recent molecular aspects with respect to heat shock protein expression in camels.

Comparison between the Effects of Adding Vitamins, Trace Elements, and Nanoparticles to SHOTOR Extender on the Cryopreservation of Dromedary Camel Epididymal Spermatozoa

Simple Summary

This is a comprehensive study to compare between the effects of different supplements (vitamins C and E, trace elements Na₂SeO₃ and ZnSO₄, and nanoparticles of zinc oxide and selenium) to the semen extender of camel epididymal spermatozoa during cooling and freezing/thawing cryopreservation. Supplementation of the semen SHOTOR extender with zinc oxide and selenium nanoparticles lead to improved progressive motility, vitality, and anti-oxidative defense, and reduced the ultrastructural abnormalities in camel epididymal spermatozoa.

Abstract

There are several obstacles in camel semen cryopreservation; such as increasing semen viscosity and the reduction in motile spermatozoa after ejaculation. Epididymal spermatozoa offer an efficient alternative to overcome these problems and are well-suited for artificial insemination in camels. In the current study, we compared the effects of supplementation with vitamin C, E, inorganic trace elements of selenium (Na₂SeO₃) and zinc (ZnSO₄), and zinc and selenium nanoparticles (ZnONPs and SeNPs, respectively) on the cryopreservation of dromedary camel epididymal spermatozoa. When the SHOTOR extender was supplemented with ZnONPs and SeNPs; the sperm showed increased progressive motility; vitality; and membrane integrity after cooling at 5 °C for 2 h; when compared to the control and vitamin-supplemented groups. Moreover, the ZnONPs and SeNPs supplementation improved the progressive motility, vitality, sperm membrane integrity, ultrastructural morphology, and decreased apoptosis when frozen and thawed. SeNPs significantly increased reduced glutathione (GSH), superoxide dismutase (SOD), and decreased lipid peroxide malondialdehyde (MDA) levels. The advantageous effects of the trace elements were potentiated by reduction into a nano-sized particle, which could increase bioavailability and reduce the undesired liberation of toxic concentrations. We recommend the inclusion of SeNPs or ZnONPs to SHOTOR extenders to improve the cryotolerance of camel epididymal spermatozoa.

Saadeldin I, Ba-Awadh H, G. Al-Mutary M, F. Moumen A, N. Alowaimer A, Abdalla H. Efficiency of Commercial Egg Yolk-Free and Egg Yolk-Supplemented Tris-Based Extenders for Dromedary Camel Semen Cryopreservation

Simple Summary

This study compared the efficiency of commercial egg yolk-free (AndroMed, OPTIXcell) and egg yolk-supplemented (Triladyl, Steridyl) Tris-based extenders for semen cryopreservation in dromedary camels. The camel-specific extender SHOTOR was used for reference. SHOTOR, Triladyl, Steridyl, AndroMed, and OPTIXcell can all be used for camel semen cryopreservation; however, SHOTOR and Triladyl provide the best post-thawing sperm quality.

Abstract

This study compared the efficiency of commercial egg yolk-free (AndroMed, OPTIXcell) and egg yolk-supplemented (Triladyl, Steridyl) Tris-based extenders for semen cryopreservation in seven adult dromedary camels. The camel-specific extender SHOTOR was used as control. The collected semen samples were evaluated and diluted with SHOTOR, Triladyl, Steridyl, AndroMed, or OPTIXcell. The diluted semen was gradually cooled and equilibrated for two hours before liquid nitrogen freezing. Semen was evaluated prior to freezing and after freeze-thawing cycles for motility, kinetics, vitality, abnormality, plasma membrane integrity, and DNA fragmentation using computer-assisted sperm analysis. In pre-freezing evaluation, progressive sperm motility was higher in SHOTOR-diluted samples (21.54 ± 1.83) than in samples diluted with Steridyl, OPTIXcell, or AndroMed (15.76 ± 1.80, 17.43 ± 1.10, and 13.27 ± 1.07, respectively). Moreover, Triladyl and SHOTOR resulted in significantly (p < 0.05) better sperm vitality and DNA integrity than all other diluents, but Triladyl resulted in a significantly (p < 0.05) better plasma membrane integrity (87.77 ± 0.31) than SHOTOR (85.48 ± 0.58). In the post-thawing evaluation, Triladyl led to significantly (p < 0.05) higher sperm motility (38.63 ± 0.81%; p < 0.05) when compared to SHOTOR, Steridyl or AndroMed (35.09 ± 1.341%, 34.4 ± 0.84%, and 31.99 ± 1.48%, respectively), with OPTIXcell being the least efficient (28.39 ± 0.86%). Progressive sperm motility was the highest when using Triladyl. Post-thawing curvilinear, straight line and average path sperm velocities were highest with Triladyl and lowest with AndroMed. Triladyl led to the highest linearity coefficient and straightness sperm coefficient, while SHOTOR to the highest DNA and plasma membrane integrity. OPTIXcell and AndroMed resulted in poor post-thawing sperm vitality, while Steridyl was less efficient than Triladyl. The highest rate of sperm abnormalities was recorded with OPTIXcell and the lowest with SHOTOR or Triladyl. In conclusion, SHOTOR, Triladyl, Steridyl, AndroMed, and OPTIXcell can all be used for camel semen cryopreservation; however, SHOTOR and Triladyl provided the best post-thawing sperm quality. Based on our findings, Triladyl is the best commercially available extender for dromedary camel semen cryopreservation to date.

Considerations for the development of a dromedary camel (Camelus dromedarius) semen collection centre

The dromedary camel (DC) is a strategic animal for the exploitation of the desert and unhospitable lands (arid and semiarid areas). These animals are a genetic resource, locally adapted and more resilient to these environs, that may significantly contribute to food security and sustainable development of marginal land areas. Artificial insemination is the least invasive, least expensive technique for improving genetic selection and minimising transmission of venereal disease among animals and herds. Besides semen preservation protocols, specific approaches for the development of DC semen collection centres - biosecurity measures, screening for infectious diseases, management of animals, welfare, nutrition, control of seasonality, training, hygiene of semen collection and processing - have been considered less important aspects. The aim of this research is to describe the aspects related to the development of a DC semen collection centre, summarising the latest studies in the field of welfare, reproduction and diseases, and describing biosecurity and hygiene aspects related to semen collection and handling. Scientific gaps and requirements for maximising the production of good quality and safe-to-use semen doses with minimal risks of disease transmission are also described.

Effect of short artificial lighting and low temperature in housing rooms during non-rutting season on reproductive parameters of male dromedary camels

Ten dromedary mature males were used to study the effects of short artificial lighting and low temperature on the reproductive behavior, testicular size, semen quality and hormone during the non-rutting season and subsequent rutting season. Bulls were allocated into two groups: the first group were subjected to natural daylight and temperature and used as a control. The second group was housed individually in light and temperature controlled rooms in which artificial light (300 lux) was used for 10 h/d, and the temperature was 25.28 ± 0.21 °C. The trial was initiated in mid-June and continued for 10 weeks in the non-rutting season. The reproductive parameters of all animals in the control and room groups were evaluated once every two weeks. The reproductive parameters of all animals in the control and room groups were re-evaluated during the rutting season of the same year. A significant (P < 0.05) increase in the morphometry of the testes, scrotum, libido, and reaction time score, as well as serum melatonin and testosterone levels, was observed in the treatment non-rutting season (TNRS) group compared to in the control non-rutting season (CNRS) group. The testicular volume, reaction time score, serum melatonin, and testosterone were significantly (P < 0.05) higher in the treatment rutting season (TRS) group than in the control non-rutting season (CRS) group. Improvement in the semen parameters were observed in the TNRS and TRS groups compared to in the CRS group. In conclusion, these results demonstrate that short artificial lighting and low temperature can induce rutting out of season and improve the reproductive parameters of dromedary males during the subsequent rutting season.

Reproductive seasonality of male dromedary camels

Reproductive seasonality has been reported in numerous species, including male dromedary camels, yet investigations into seasonal changes in camel semen quality have yet to be conducted. The aim of this study was to characterise the seasonal changes in camel semen quantity and quality as well as correlate these changes to testis and accessory sex gland morphology, sexual behaviour, libido and environmental factors such as day length and ambient temperature in Oman. Semen was collected twice a month for a year and testicular and accessory sex organ biometry recorded once a month via ultrasonography (n = 8 bulls). Blood samples were collected monthly to assess testosterone levels. Results indicated that testes and accessory sex glands size increased during October-April, peaking with testosterone concentrations during January (P<0.05). The sexual behaviour and libido of camels was also greater during the months of October-April (P<0.05). Attempts to collect semen were 100% successful during November-February. Semen volume, as well as sperm gross activity, concentration, motility, average path velocity and percentage with intact acrosomes were the greatest during January and decreased from May-September (P<0.05). Changes in values for semen variables, testosterone concentrations and sex organ anatomy were also highly correlated with seasonal changes in day length and ambient temperatures. In conclusion, a clearly defined reproductive season was observed in male camels in Oman ranging from December-March, with peak reproductive function occurring during December-January. To increase the success of breeding programs, matings or semen collections should be timed to occur when reproductive function is maximal.

Effects of melatonin implants on the reproductive performance and endocrine function of camel (Camelus dromedarius) bulls during the non-breeding and subsequent breeding seasons

This study aimed to evaluate the effects of melatonin implants on the reproductive performances and hormone levels of dromedary (Camelus dromedarius) bulls during the non-breeding and subsequent breeding seasons. Fourteen mature dromedary bulls were divided into a control group (n = 7) and a group that was implanted with melatonin (n = 7) twice, at the beginning of the study and 35 days later. The trial started on the 17th June and continued for 10 weeks during the non-breeding season. Reproductive performances of animals in the control and melatonin groups were evaluated weekly during the non-breeding season [control non-breeding (CNB) and melatonin non-breeding (MNB) groups, respectively] and evaluated again during the subsequent breeding season [control breeding (CB) and melatonin breeding (MB) groups, respectively], which started on the 6th December and continued for 10 weeks. MNB bulls had greater (P ≤ 0.05) scrotum circumference and testicular volume, sexual desire, reaction time and mating ability scores, and serum melatonin and testosterone concentration values (24.91 ± 0.26 cm, 271.00 ± 7.81 cm³, 2.31 ± 0.13, 2.03 ± 0.22, 2.26 ± 0.09, 23.90 ± 0.05 pg/mL and 2764.51 ± 137.02 pg/mL, respectively) than the CNB group (23.63 ± 0.05 cm, 199.21 ± 3.27 cm³, 1.00 ± 0.00, 0.00 ± 0.00, 1.00 ± 0.00, 9.46 ± 0.08 pg/mL and 1872.41 ± 264.89 pg/mL, respectively). The scrotum and testes, reaction time score, proportion of bulls refusing to mount, and serum melatonin values were significantly higher in MB than CB bulls (P ≤ 0.05). Progressive motility (PM), average pathway velocity, straight-line velocity, curvilinear velocity (VCL), linearity, straightness (STR), wobble, beat cross frequency (BCF), livability, and DNA integrity were significantly higher in MB than CB bulls (P ≤ 0.05). PM, VCL, STR, amplitude of lateral head displacement, BCF, and livability were significantly higher in MNB than CB bulls (P ≤ 0.05). In conclusion, melatonin implants improved the reproductive performance of bulls during the non-breeding and subsequent breeding seasons.