Dromedary camel nanobodies broadly neutralize SARS-CoV-2 variants.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike is a trimer of S1/S2 heterodimers with three receptor-binding domains (RBDs) at the S1 subunit for human angiotensin-converting enzyme 2 (hACE2). Due to their small size, nanobodies can recognize protein cavities that are not accessible to conventional antibodies. To isolate high-affinity nanobodies, large libraries with great diversity are highly desirable. Dromedary camels (Camelus dromedarius) are natural reservoirs of coronaviruses like Middle East respiratory syndrome CoV (MERS-CoV) that are transmitted to humans. Here, we built large dromedary camel VHH phage libraries to isolate nanobodies that broadly neutralize SARS-CoV-2 variants. We isolated two VHH nanobodies, NCI-CoV-7A3 (7A3) and NCI-CoV-8A2 (8A2), which have a high affinity for the RBD via targeting nonoverlapping epitopes and show broad neutralization activity against SARS-CoV-2 and its emerging variants of concern. Cryoelectron microscopy (cryo-EM) complex structures revealed that 8A2 binds the RBD in its up mode with a long CDR3 loop directly involved in the ACE2 binding residues and that 7A3 targets a deeply buried region that uniquely extends from the S1 subunit to the apex of the S2 subunit regardless of the conformational state of the RBD. At a dose of ≥5 mg/kg, 7A3 efficiently protected transgenic mice expressing hACE2 from the lethal challenge of variants B.1.351 or B.1.617.2, suggesting its therapeutic use against COVID-19 variants. The dromedary camel VHH phage libraries could be helpful as a unique platform ready for quickly isolating potent nanobodies against future emerging viruses.

Biphasic MERS-CoV Incidence in Nomadic Dromedaries with Putative Transmission to Humans, Kenya, 2022-2023.

Middle East respiratory syndrome coronavirus (MERS-CoV) is endemic in dromedaries in Africa, but camel-to-human transmission is limited. Sustained 12-month sampling of dromedaries in a Kenya abattoir hub showed biphasic MERS-CoV incidence; peak detections occurred in October 2022 and February 2023. Dromedary-exposed abattoir workers (7/48) had serologic signs of previous MERS-CoV exposure.

Abundance of selected genes implicated in testicular functions in Camelus dromedarius with high and low epididymal semen quality.

Studying testicular genes' expression may give key insights into precise regulation of its functions that influence epididymal sperm quality. The current study aimed to investigate the abundance of candidate genes involved in the regulation of testicular functions specially those regulate sperm function (PLA2G4D, SPP1, and CLUAP1), testicular steroidogenic function (ESR1 and AR), materials transport (AQP12B and LCN15), and defense mechanisms (DEFB110, GPX5, SOCS3, and IL6). Therefore, blood samples and testes with epididymis were collected from mature middle-aged (5-10 years) dromedary camels (n = 45) directly prior and after their slaughtering, respectively, during breeding season. Sera were evaluated for testosterone level and testicular biometry was measured with caliper. The epididymal tail semen was evaluated manually. Samples were distinguished based on testosterone level, testicular biometry, as well as epididymal semen features into high and low fertile groups. Total RNA was isolated from testicular tissues and gene expression was done using Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Results revealed that testosterone levels were significantly (P < 0.005) higher in camels with good semen quality than those of low quality. There was a significant (P < 0.0001) increase in testicular weight, length, width, thickness, and volume in high fertile than low fertile camels. PLA2G4D, SPP1, CLUAP1, ESR1, AR, AQP12B, LCN15, DEFB110, GPX5, and SOCS3 genes were upregulated (P < 0.001), and IL6 gene was downregulated (P < 0.01) in the testes of high fertile camels compared to the low fertile one. Thus, it could be concluded that examined genes might be valuable monitors of testicular functional status and fertility in dromedary camels.

Identification of novel genetic loci related to dromedary camel (Camelus dromedarius) morphometrics, biomechanics, and behavior by genome-wide association studies.

In the realm of animal breeding for sustainability, domestic camels have traditionally been valued for their milk and meat production. However, key aspects such as zoometrics, biomechanics, and behavior have often been overlooked in terms of their genetic foundations. Recognizing this gap, the present study perfomed genome-wide association analyses to identify genetic markers associated with zoometrics-, biomechanics-, and behavior-related traits in dromedary camels (Camelus dromedarius). 16 and 108 genetic markers were significantly associated (q < 0.05) at genome and chromosome-wide levels of significance, respectively, with zoometrics- (width, length, and perimeter/girth), biomechanics- (acceleration, displacement, spatial position, and velocity), and behavior-related traits (general cognition, intelligence, and Intelligence Quotient (IQ)) in dromedaries. In most association loci, the nearest protein-coding genes are linkedto neurodevelopmental and sensory disorders. This suggests that genetic variations related to neural development and sensory perception play crucial roles in shaping a dromedary camel's physical characteristics and behavior. In summary, this research advances our understanding of the genomic basis of essential traits in dromedary camels. Identifying specific genetic markers associated with zoometrics, biomechanics, and behavior provides valuable insights into camel domestication. Moreover, the links between these traits and genes related to neurodevelopmental and sensory disorders highlight the broader implications of domestication and modern selection on the health and welfare of dromedary camels. This knowledge could guide future breeding strategies, fostering a more holistic approach to camel husbandry and ensuring the sustainability of these animals in diverse agricultural contexts.

Serological and histolomorphological investigation of camel bulls testes (Camelus dromedaries) during the rutting and non-rutting seasons.

BACKGROUND: Camels are bred for their milk, meat, wool and hair, transportation, and their excrement as fuel. The seasonal reproduction of camel bull is accompanied by changes in sexual activity, the morphology, and function of the testes. This study aimed to evaluate the seasonal fluctuations in serum testosterone (T) levels as well as total antioxidant capacity (TAC) and malondialdehyde (MDA) levels in the testes of dromedary bulls (Camelus dromedarius) during the rutting and non-rutting seasons. Moreover, the impact of rutting season on the testicular size and histomorphology was also observed. Seventy mature dromedary bulls were divided into a rutting group (n = 35) and a non-rutting group (n = 35). From these bulls, blood samples and testes were collected during the rutting season (October to April) and non-rutting season (May to September) from a local slaughterhouse. RESULTS: All parameters changed significantly during rutting and non-rutting periods in camel bulls. The levels of TAC in testes, and serum T were significantly (P < 0.05) higher in the rutting group than in the non-rutting group. However, testicular MDA was significantly (P < 0.05) lower in the rutting group than in the non-rutting group. TAC was negatively correlated with MDA (r = -0.59, p < 0.01). Moreover, in the rutting group and the non-rutting group, T was positively correlated with levels of TAC (r = 0.66, p < 0.0003). Additionally, testicular size (length, breadth, and thickness) was significantly greater in camels during the rutting season than in camels during the non-rutting season. Moreover, the number and diameter of seminiferous tubules, and spermatogenesis increased during the rutting season, whereas, the collagen content and apoptosis increased during the non-rutting season. CONCLUSION: This study revealed that the rutting normal breeding season (NBS, rutting group) was associated with higher levels of total antioxidant capacity (TAC), T, and spermatogenic activity while the collagen content, concentrations of MDA (the oxidative stress factor) and apoptosis (an outcome of oxidative stress) were lower than those in the low breeding season (LBS, non-rutting group). In addition, the testicular size and seminiferous tubule diameter and number were higher during the NBS.

Osteopontin expression in dromedary camel's conceptuses during the peri-implantation period.

The reproductive efficiency of dromedary camels is hindered by challenges such as early embryonic mortality, which may be attributed to a lack of synchronization between conceptus signalling and uterine receptivity. Understanding the intricate biological processes involved in feto-maternal interactions during implantation is crucial to address these limitations. Osteopontin (OPN) is a protein involved in cell signalling and adhesion, playing a crucial role in embryonic implantation. Previous studies have shown the presence of OPN in the uterine endometrium of various mammalian species including dromedary camels. However, the expression pattern of OPN in dromedary conceptuses remains unexplored. Thus, the current study aimed, for the first time, to investigate the temporospatial expression of OPN in dromedary conceptuses during the peri-implantation period at Days 8, 10, and 12 of pregnancy. Twelve conceptuses were recovered non-surgically from pregnant females on Days 8, 10, 12 of pregnancy. Quantitative real-time PCR (qrt-PCR), immunohistochemistry (IHC), and immunofluorescence (IF) were employed for analysis of the expression of OPN mRNA and protein. The results revealed significant increases in both OPN mRNA and protein expression started on Day 10 and peaked at Day 12 of pregnancy. Immuno-localization confirmed the presence of OPN protein in the trophectoderm and endoderm of dromedary conceptuses. In conclusion, the expression and localization of OPN during the peri-implantation period in dromedary conceptuses imply its involvement as a crucial reproductive factor and its upregulation during this period, with a pronounced increase close to attachment time (Day 12 of pregnancy) further supports its role in embryo adhesion, implantation, and placentation.

Uterotubal junction of the bovine (Bos taurus) versus the dromedary camel (Camelus dromedarius): Histology and histomorphometry.

This study aims to conduct a comparative analysis of the uterotubal junction in two distinct mammalian species, the bovine (Bos taurus) and the dromedary camel (Camelus dromedarius), focusing on histological and histomorphometric parameters. Uterotubal junction (UTJ) was dissected from 8 cows and 12 camels with dominant follicles, and processed for H&E staining for histology, and histomorphometry examination. The results showed that the camel uterotubal junction papillae (UTJP) existed only in camels and was completely absent in cattle. Histologically, the cow UTJ appears with a star-shaped lumen, and the mucosa is lined by a simple columnar epithelium with ciliated and non-ciliated cells. Superficial (SG) and deep glands (DG) were abundant in the submucosa. Camel UTJP is a conical structure, it has a pale yellowish colour, 0.5 ± 0.2 cm height, and 0.3 ± 0.1 cm width, and it has a distinct sphincter at the tip towards the uterine lumen. In the camel UTJP, the lumen is wider, and the mucosa showed large multiple folds lined with ciliated and non-ciliated cells in a pseudostratified columnar epithelium. The submucosa showed no mucosal glands. Lumen area, lumen epithelial height, luminal epithelial density, the thickness of the muscular layer, number of folds, fold height, epithelial height, fold area and epithelial perimeter were higher in camel UTJP (p < .001) than cow UTJ, while the total endosalpinx area and glandular epithelial density were lower in camel UTJP (p < .001) than in cow UTJ. In conclusion, this study elucidates potential variations in the uterotubal junction between bovines and dromedary camels, providing valuable insights into their reproductive adaptations. The epithelial lining, absence of glands and the thick layer of tunica muscularis might indicate that camel UTJP could play a mechanical role in selecting spermatozoa and assisting the hatching of blastocysts during their passage into the uterus.

Region-specific gene expression profile in the epididymis of high- and low-fertile dromedary camels.

The scenario of the fertile spermatozoa with high fertilizing capability is basically dependent on gene expression-based epididymal function. The current investigation aimed to declare the varied expression of different candidate genes (PLA2G4D, LCN15, CLUAP1, SPP1, AQP12B, DEFB110 and ESR1) relevant to spermatozoa features between the different epididymal segments in the mature dromedary camels (n = 30). Scrotal contents were collected post-slaughtering, during the breeding season and the epididymis was separated from the testicles and divided into three segments (caput, corpus and cauda) based on its morphology and anatomical characteristics. Epididymal spermatozoa were harvested from each epididymal portion and evaluated for motility, count, viability and morphology. Samples were grouped depending on their epididymal sperm cells features into high-fertile (n = 15) and low-fertile (n = 15) groups. The gene expression of the candidate genes was defined in the isolated RNA from each epididymal portion tissue. The segmental sperm motion and count were significantly (p < .05 and p < .01) higher in the three epididymal parts of high-fertile camels than the lower ones. There were some candidate genes markedly up-regulated in its expression in epididymal head of high-fertile camels (PLA2G4D and LCN15) and low fertile (CLUAP1), while others in the body region of the high-fertile group (SPP1, AQP12B and DEFB110). Nevertheless, ER1 did not differ in the expression among the epididymal segments. In conclusion, the variant expression patterns of these epididymal genes in relation to the regional spermatozoa features might suggest important roles of these genes in sperm maturation process in the epididymis and focusing more interest on their potential utility as markers for male camel fertility prediction.

Differential cellular localization of lectins in the testes of dromedary camel (Camelus dromedarius) during active and inactive breeding seasons.

The reproductive activity of the male dromedary camel (Camelus dromedarius) as a seasonal breeder is affected by various seasonal changes that reflect on the reproductive performance. In the current study, we explored a differential cellular localization of lectins in eight dromedary camel testes utilizing lectin histochemistry (LHC). The glycoconjugates' localizations were detected within the testicular tissue utilizing 13 biotin-labeled lectins (PNA, ConA, LCA, RCA120, GS IB4, WGA, BPL, DBA, ECA, PHA-E4, UEA-1, PTL-II, and SBA) distributed into six sets. The cellular structures revealed diverse lectins distribution that may reflect various glycoproteins' structures and their compositional modifications during spermatogenesis. Some of the investigated lectins were restricted to acrosomes of spermatids that will help study different stages during the spermatogenic cycle of dromedary camel, particularly PNA, and ECA. The statistical analysis showed a marked positive correlation between the response intensity of various lectins and the breeding season (P < 0.05). We can conclude that lectins have a fundamental role during camel spermatogenesis and are associated with the reproductive activity of dromedary camel.

A longitudinal study of Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels.

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV) was identified in humans in 2012. Since then, 2605 cases and 937 associated deaths have been reported globally. Camels are the natural host for MERS-CoV and camel to human transmission has been documented. The relationship between MERS-CoV shedding and presence of neutralizing antibodies in camels is critical to inform surveillance and control, including future deployment of camel vaccines. However, it remains poorly understood. The longitudinal study conducted in a closed camel herd in Egypt between December 2019 and March 2020 helped to characterize the kinetics of MERS-CoV neutralizing antibodies and its relation with viral shedding. RESULTS: During the 100-day longitudinal study, 27 out of 54 camels (50%) consistently tested negative for presence of antibodies against MERS-CoV, 19 (35.2%) tested positive and 8 (14.8%) had both, positive and negative test results. Fourteen events that could be interpreted as serological indication of probable infection (two seroconversions and twelve instances of positive camels more than doubling their optical density ratio (OD ratio) in consecutive samples) were identified. Observed times between the identified events provided strong evidence (p = 0.002) against the null hypothesis that they occurred with constant rate during the study, as opposed to clustering at certain points in time. A generalized additive model showed that optical density ratio (OD ratio) is positively associated with being an adult and varies across individual camels and days, peaking at around days 20 and 90 of the study. Despite serological indication of probable virus circulation and intense repeated sampling, none of the tested nasal swab samples were positive for MERS-CoV RNA, suggesting that, if the identified serological responses are the result of virus circulation, the virus may be present in nasal tissue of infected camels during a very narrow time window. CONCLUSIONS: Longitudinal testing of a closed camel herd with past history of MERS-CoV infection is compatible with the virus continuing to circulate in the herd despite lack of contact with other camels. It is likely that episodes of MERS-CoV infection in camels can take place with minimal presence of the virus in their nasal tissues, which has important implications for future surveillance and control of MERS-CoV in camel herds and prevention of its zoonotic transmission.

Parasitological, molecular, and epidemiological investigation of Trypanosoma evansi infection among dromedary camels in Balochistan province.

Surra is a zoonotic disease caused by Trypanosoma evansi (T. evansi), which affects a wide variety of animals worldwide. The disease has a severe impact on the productivity, health, and working capacity of camels and causes mortality and extensive economic losses if not diagnosed early. This is the first comprehensive report on the prevalence of T. evansi infection in dromedaries in Balochistan province. In the present study, 393 blood samples (indigenous, n = 240; imported, n=153) were collected from one-humped camels (Camelus dromedarius) and were tested by molecular methods to estimate the prevalence of T. evansi in three districts (Pishin, Nushki, and Lasbella) of Balochistan province. The overall prevalence of T. evansi among examined camel samples was 28.24% (95% confidence interval (CI): 24.02-32.89%). The risk of T. evansi infection in adult camels (> 10 years) is higher than that in young ones (odd-ration (OR) = 2.7; 95% CI: 1.3357-5.3164%). Moreover, male camels were six times more likely to get an infection than female camels. The detection of T. evansi infection in camels sampled in summer and spring was 3.12- and 5.10-fold higher, respectively, than in camels sampled in winter. In conclusion, our findings showed a high rate of T. evansi infection in camels from the three districts. Our study emphasizes the need for a strict surveillance program and risk assessment studies as prerequisites for control measures.

Influences of glycine supplementation during vitrification on the developmental potential of vitrified/warmed immature dromedary camel oocytes.

Oocytes experience detrimental osmotic stress during vitrification and warming procedures because of the osmolality imbalance between the vitrification-warming fluids and the intracellular environment. Cellular osmotic homeostasis can be preserved by glycine, a powerful osmolyte with antioxidant properties. We aimed to examine the influences of supplementing glycine to the vitrification solutions (VS) on the developmental potential of vitrified/warmed immature dromedary camel oocytes following IVM/IVF and in vitro embryo culture (IVC). Cumulus oocyte complexes (COCs) were collected from dromedary camel ovaries and randomly allocated into two groups namely control (oocytes subjected directly to IVM) and vitrified (COCs were vitrified into VS supplemented with 0.0, 0.5, 1.0 or 2.0 mM glycine). For vitrification, COCs were equilibrated for 3 min in 12.5% ethylene glycol; EG plus 12.5% dimethyl sulfoxide; DMS and then they were vitrified for 60 s in VS composed of 25% EG + 25% DMSO using solid surface vitrification (SSV). Warming of vitrified oocytes was conducted in decreasing concentrations of trehalose solution. Following vitrification and warming, the morphologically viable oocytes were subjected to IVM for 36 h. Matured oocytes were then fertilized in vitro by epididymal spermatozoa and cultured for seven days. The results showed that the percentage of viable oocytes assessed by trypan blue stain was significantly higher (p ≤ .05) in the 1.0 mM glycine-supplemented group than 0.0- and 2.0-mM glycine-supplemented ones (90.0 % vs. 80.0% and 76.6%, respectively). However, no significant difference was observed between 0.5 mM glycine and other vitrified groups. Nuclear maturation rates, cleavage (48-h post-insemination; pi) and blastocyst rate (7-days pi) were significantly lower in vitrified groups than control ones (p ≤ .05). Among vitrified groups, these parameters were the highest in the 1.0 mM glycine-supplemented group. Taken together, supplementation of vitrification solutions with 1.0 mM glycine could enhance the developmental potential of vitrified/warmed immature dromedary camel oocytes.

Udder, teat, and milk vein measurements of Indian dromedary camel and its relationship with milkability traits.

The economic viability of the camel in the current scenario can be ensured by improving its dairy potential. The study on the udder and teat characteristics of dromedary camel and understanding its relationship with milk yield and milkability can be of great value in establishing camel as a dairy animal. The present study was conducted on 45 lactating she-camels of four Indian camel breeds, viz., Bikaneri, Jaisalmeri, Kachchhi, and Mewari, stationed at ICAR-NRCC Bikaner, Rajasthan, India. The udder, teat, and milk vein measurements traits, factors affecting these traits and their relationship with milkability traits, were studied in hand-milked Indian dromedary camel. The means ± S.E. of teat lengths (TL), namely, left fore (LF), left rear (LR), right fore (RF), and right rear (RR), were observed as 52.21 ± 1.66, 58.52 ± 2.11, 50.13 ± 1.74, and 54.37 ± 1.82 mm, respectively. The means ± S.E. of teat diameter (TD), namely, left fore, left rear, right fore, and right rear teat diameters, were observed as 42.44 ± 1.60, 46.01 ± 1.68, 39.29 ± 1.31, and 45.20 ± 1.56 mm, respectively. The means ± S.E for udder depth, udder length, udder height from the ground, milk vein diameter, and milk vein length were observed as 25.44 ± 0.42, 37.29 ± 0.80, 114.80 ± 0.80, 2.02 ± 0.08, and 88.70 ± 0.96 cm, respectively. Udder and milk vein measurements did not differ significantly between breeds. Kachchhi breed has largest teat length and diameter. The breed differences were significant (p ≤ 0.05) for TL-LF, TL-RF, and TD-RR only. The effect of parity was non-significant on udder, teat, and milk vein measurement traits except TD-RR (p ≤ 0.05); however, second parity animals had higher values for all the studied traits except udder height from ground. Positive and highly significant (p ≤ 0.01) correlation of milk yield was observed with the majority of udder, teat, and milk vein measurements, milking time, and milk flow rate, while a negative correlation was found with udder height from ground and milk let-down time. It can be concluded that udder characteristics are influenced by various genetic and non-genetic factors and its relationship with milk yield and milkability can be used for selection and dairy management purposes.

Factors affecting outcomes of embryo transfer in dromedary camels: A retrospective study.

The present study aimed to use a comprehensive approach for evaluating 12 factors related to embryo quality (shape, size and transparency), donors (age, ET type, number of recovered embryos and day of uterine flushing), recipients (age), males (age and individual variations) and environment (season and year) which could affect the outcome of ET in terms of pregnancy (PR) and pregnancy losses in dromedary camels. During three breeding seasons, 116 donor females were mated repeatedly at 12- to 14-day intervals by fertile male camels (n = 33) without stimulation of the ovaries (WSPO). Superovulation (SPO ET) regimen was applied for each donor female twice or thrice per season. In the occasions of applying superovulation regimen, donor females having an ovulatory follicle were mated instead of GnRH administration and superovulation regimen was applied 4 days post-mating (MIX ET). The uteri of all donor females were flushed at Day 8 or 9 post-mating, and a total of 2,095 embryos were recovered and transferred individually to 924 recipient females. Pregnancy diagnoses were conducted at Day 10 after ET (Days 18-19 of gestation) by using progesterone assay and by transrectal ultrasonography (TRU) at Days 30 and 60 of gestation. By using logistic regression analysis, transparency of embryos and age of recipient females had significant effects on PR at Days 18-19 (p < .01), 30 (p < .01) and 60 (p < .01; p < .05, respectively) of gestation. The shape of embryos had significant effects on the PR at Days 30 (p < .05) and 60 (p < .01) of gestation. Type of ET and the breeding season (year) had significant (p < .05) effects on the PR at Day 30, while day of flushing had the same effect on PR at Day 60. Regarding the pregnancy losses, transparency and shape of the embryo, type of ET, breeding season had significant (p < .05) effect on the late embryonic mortalities (LEM) and shape and season of year had significant (p < .01 and p < .05, respectively) effect on LEM/early foetal mortalities (EFM). Regarding male individual factor, there was a tendency for a significant (p = .055) effect of male camels on the PR at Days 18-19 and rate of LEM. In conclusion, transferring a spherical, transparent or a large-sized embryo (>750 µm) into recipient females ageing between 8 and 11 y could greatly improve the PR from Days 18 to 60 of gestation. Also, embryo recovered from donor females with Mix ET type or embryos sired by certain male camel or at Day 8 post-mating of the donor could improve the 2-month PR. In addition, transferring a transparent or spherical-shaped embryo or embryos recovered from donor females with SPO or Mix ET could reduce the pregnancy losses during the first 2 months of pregnancy.

Accuracy of image analysis for linear zoometric measurements in dromedary camels.

The present study was designed to verify the effectiveness of the image analysis method for body measurement in dromedary camel compared to manual measurements as a reference method. To achieve this aim, twenty-one linear body measurements were estimated on 59 adult Sahraoui dromedary camels (22 males and 37 females) with a normal clinical condition by using a measuring stick or vernier caliper (standard method). On the other hand, image analysis on profile, front, or behind photographs was processed using Axiovision Software. Overall mean comparison, relative error, variance, Pearson's correlation coefficient, and coefficient of variance showed that the image analysis method was accurate in relation to the manual measurement. Furthermore, image analysis results indicated relevant accuracy (bias correction factor, Cb ≈1) and precision (Pearson ρ ≈1) which were significantly correlated with the results of the reference method (Lin's concordance correlation coefficients rccc ≈ 1). According to Bland-Altman upper and lower limits of agreement, the concordance was estimated between 93.22 and 98.3%. Passing-Bablok regression showed a good relationship between the results of the two methods displaying no significant systematic and proportional bias. The image analysis method for linear body measurements in dromedary camel showed results that are in agreement with the manual measuring method. Therefore, the image analysis could be considered a valid tool for camel conformation trait studies.

Comparative study on lesions of reproductive disorders of cows and female dromedary camels slaughtered at Addis Ababa, Adama and Akaki abattoirs with bacterial isolation and characterization.

BACKGROUND: Reproduction is a basic prerequisite to efficient livestock production. Reproductive performance depends on the normal structure and function of genital organs. A cross-sectional study was conducted from November 2016 to May 2017 to identify and compare the frequency of reproductive tract pathological lesions and to isolate bacteria associated to uterine lesions in female dromedary camels and cows slaughtered at Akaki camel slaughterhouse and Addis Ababa and Adama municipal abattoirs. Purposive sampling technique was employed to include and examine the reproductive tracts of all slaughtered animals (280; 140 cows and 140 camels) during the study period. RESULT: The study examined a total of 280 (140 cows and 140 camels) reproductive tracts. Various pathological lesions with different degrees of severity were observed in 48 (34.2%) and 51 (36.4%) of dromedary camels and cows, respectively. In dromedary camels, the most prevalent lesion was uterine lesions (21.4%) followed by ovarian lesions (7.14%); while in cows, ovarian lesions were the most prevalent (16.4%) followed by uterine lesions (14.2%). In general, 56 bacteria were isolated from cows' uterine lesion, the Staphylococcus species (28.5%), Streptococci species (19.6%), Coynebacterium species (8.9%), Escherichia coli (26.78%), Salmonella species (10.7%) and Klebsiella species (5.35%) being the most representative isolates. In camels, however, 45 bacteria were isolated from uterine lesions with higher prevalence of Escherichia coli (35.5%), Staphylococcus species (26.6%), Streptococcus species (13.3%), Pseudomonas species (6.6%), Proteus species (4.4%), Salmonella species (8.8%) and Klebsiella species (4.4%). Bacteriological data showed that the major isolates were similar, although slightly more frequent in occurrence in cows. Microscopically, uterine inflammatory lesions evidenced endometrial glands degeneration, epithelium sloughing, peri-glandular cuffing, and inflammatory cells infiltration. CONCLUSIONS: In female dromedary camels and cows, pathological lesions of the reproductive tract showed great prevalence, with similarity in bacterial isolates in both species. The role of each reproductive lesion and bacterial isolates as causal agents of reproductive failures in these livestock species, however, needs further investigation.

Bacterial species-specific modulatory effects on phenotype and function of camel blood leukocytes.

BACKGROUND: Recent studies have reported pathogen-species-specific modulating effects on the innate immune system. Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae are important pathogenic bacteria responsible for different infectious diseases in several animal species. In the present study, a whole blood culture with S. aureus, E. coli, or S. agalactiae and flow cytometry were used to investigate, whether stimulation with different bacterial species induces different immunomodulation patterns in camel leukocytes. The expression of different cell surface myeloid markers and cell adhesion molecules on monocytes and neutrophils was investigated. In addition, the capacity of monocytes and neutrophils to produce reactive oxygen species (ROS) was analyzed. RESULTS: Stimulation with either of the bacterial species resulted in the expansion of the camel CD14highMHCIIhigh monocyte subset with a reduced fraction of CD14highMHCIIlow monocytes. For the CD14lowMHCIIhigh monocytes, however, only stimulation with S. aureus or S. agalactiae increased their fractions in blood. Although all bacterial species elicited the upregulation of cell surface MHC class II molecules on granulocytes, the increase was, however, highest on cells stimulated with S. aureus. The expression levels of the two adhesion molecules, CD11a and CD18, on neutrophils and monocytes were differently affected by bacterial stimulation. Functionally, E. coli failed to stimulate ROS production in monocytes, while induced a strong ROS production response in granulocytes. S. agalactiae elicited a week ROS production in granulocytes when compared to the other two pathogens. CONCLUSIONS: The different responsiveness of monocytes and granulocytes toward different bacterial species indicates different host-pathogen interaction mechanisms for the two cell populations. In addition, the phenotypic and functional differences between cells stimulated with E. coli, S. aureus, or S. agalactiae suggests pathogen-species-specific modulating effects of the bacterial pathogens on the camel innate myeloid cells.

Oocyte vitrification induces loss of DNA methylation and histone acetylation in the resulting embryos derived using ICSI in dromedary camel.

Oocyte cryopreservation has become an important component of assisted reproductive technology with increasing implication in female fertility preservation and animal reproduction. However, the possible adverse effects of oocyte cryopreservation on epigenetic status of the resulting embryos is still an open question. This study evaluated the effects of MII-oocyte vitrification on gene transcripts linked to epigenetic reprogramming in association with the developmental competence and epigenetic status of the resulting embryos at 2-cell and blastocyst stages in dromedary camel. The cleavage rate of vitrified oocytes following intracytoplasmic sperm injection was significantly increased compared with the control (98.2 ± 2 vs. 72.7 ± 4.1%, respectively), possibly due to the higher susceptibility of vitrified oocytes to spontaneous activation. Nonetheless, the competence of cleaved embryos derived from vitrified oocytes for development to the blastocyst and hatched blastocyst was significantly reduced compared with the control (7.7 ± 1.2 and 11.1 ± 11.1 compared with 28.1 ± 2.6 and 52.4 ± 9.9%, respectively). The relative transcript abundances of epigenetic reprogramming genes DNMT1, DNMT3B, HDAC1, and SUV39H1 were all significantly reduced in vitrified oocytes relative to the control. Evaluation of the epigenetic marks showed significant reductions in the levels of DNA methylation (6.1 ± 0.3 vs. 9.9 ± 0.5, respectively) and H3K9 acetylation (7.8 ± 0.2 vs. 10.7 ± 0.3, respectively) in 2-cell embryos in the vitrification group relative to the control. Development to the blastocyst stage partially adjusted the effects that oocyte vitrification had on the epigenetic status of embryos (DNA methylation: 4.9 ± 0.4 vs. 6.2 ± 0.6; H3K9 acetylation: 5.8 ± 0.3 vs. 8 ± 0.9, respectively). To conclude, oocyte vitrification may interfere with the critical stages of epigenetic reprogramming during preimplantation embryo development.

Genetic parameters of gestation length trait in dromedary camels (Camelus dromedarius).

Gestation length (GL) data of dromedary camels were analysed for the period from 2007 to 2018. The database of the largest dairy camel herds (Dubai, United Arab Emirates) was used in this study. The data of 4,084 camels included in the assessment were classified into six ecotypes (Emirati, Emirati cross, Black, Pakistani, Saudi-Sudanese and Saudi cross). The aim of the study was to describe the heritability of GL of camels and the breeding value (BV) of sires for this trait. The genetic parameters of GL were estimated by the General Linear Model method and two Best Linear Unbiased Prediction (BLUP) animal models as well. The mean (±SE) of GL of camels was 384.3 ± 0.2 days. The direct heritability of GL (0.26 ± 0.06-0.36 ± 0.08) was higher than the maternal heritability (0.00 ± 0.05-0.13 ± 0.06) obtained. The maternal permanent environmental effect (0.15 ± 0.05) was similar to the results estimated previously in dromedary camel, but higher than the data reported by relevant sources in other species. Based on the results of this study it can be concluded that the GL of dromedary camels is a species-specific value similar to that in cattle, which is less affected by the maternal influence. Considerable differences (16 days) exist among male dromedaries in their BV for the GL trait.

Effects of two different management systems on hormonal, behavioral, and semen quality in male dromedary camels.

Effects of two different management systems on male dromedary camel hormones, behaviors, and semen parameters were documented. Camels (n=6) were tested under two management systems: (i) housed in single boxes with 1-h freedom (H23); (ii) exposed to females for 17 h (from 3.30 p.m. to 8.30 a.m.) and then housed (ConExF). Blood was collected every morning; camel behavior was recorded twice a day: (i) from 7:00 to 8:00 a.m. to determine the short effects; (ii) from 2:00 to 3:00 p.m. to determine the long effects. Each camel underwent a female parade and semen collection thrice a week; sexual behavior, libido, and semen parameters were assessed. Testosterone and cortisol concentrations were higher in ConExF than H23. Compared to the H23 group, ConExF group spent more time walking, standing tripods, and looking outside their pen/box but they spent less time eating, ruminating, resting, standing, and showing stereotypical behaviors. In the morning, ConExF group spent more time walking, ruminating, and showing typical sexual behaviors compared to themselves during afternoon time and the H23 group. However, in the afternoon time, ConExF camels put more time their heads outside the box through the window and showed higher frequencies of stereotypies, probably due to a higher level of frustration. While the sexual behavioral score was higher and ejaculates showed a higher fraction of milky white and white-colored semen in ConExF than H23 group, their libido was similar. Overall, 17 h of exposure led to an increase in testosterone and cortisol levels, enhancing sexual behavior and semen color, but leading to frustration.