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1.
Sci Rep ; 14(1): 13718, 2024 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-38877059

RESUMO

In their natural environment, animals face a variety of ecological and social challenges, which might be linked to the emergence of different cognitive skills. To assess inter-specific variation in cognitive skills, we used ungulates as a study model, testing a total of 26 captive individuals across 5 different species (i.e., dwarf goats, Capra aegagrus hircus, llamas, Lama glama, guanacos, Lama guanicoe, zebras, Equus grevyi, and rhinos, Diceros bicornis michaeli). Across species, we used the same well-established experimental procedures to test individuals' performance in naïve physics tasks, i.e. object permanence, short-term spatial memory, causality, understanding of object properties, and gravity. Our results revealed that study subjects showed object permanence, were able to remember the position of hidden food after up to 60 s, and inferred the position of hidden food from the sound produced or not produced when shaking containers. Moreover, they showed an understanding of basic object properties, being able to locate objects hidden behind occluders based on their size and inclination, and could reliably follow the trajectory of falling objects across different conditions. Finally, inter-specific differences were limited to the understanding of object properties, and suggest that domesticated species as goats might perform better than non-domesticated ones in tasks requiring these skills. These results provide new information on the cognitive skills of a still understudied taxon and confirm ungulates as a promising taxon for the comparative study of cognitive evolution.


Assuntos
Memória Espacial , Animais , Memória Espacial/fisiologia , Masculino , Feminino , Cabras/fisiologia , Memória de Curto Prazo/fisiologia , Cognição/fisiologia , Gravitação , Especificidade da Espécie , Camelídeos Americanos/fisiologia
2.
Theriogenology ; 216: 177-184, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38185017

RESUMO

Recent studies document the LH-releasing pathway of nerve growth factor (NGF) in male camelids and that the LH response to seminal NGF is associated with elevated plasma testosterone concentration. Results provide rationale for the hypothesis that NGF in semen is associated with male fertility. In Experiment 1, the association between the amount of NGF in the ejaculate and characteristics of the male reproductive system was examined in alpacas. The concentration of NGF was measured by radioimmunoassay in semen samples collected from male alpacas (n = 47) and correlated with sperm morphology and motility, and measurements of the male reproductive anatomy. Most ejaculates had NGF concentrations that, based on previous studies, triggered ovulation in female camelids, however, we only found a positive correlation between NGF concentration with sperm concentration, thread formation and total NGF, and a negative correlation with pH. In Experiment 2, a retrospective analysis was carried out to determine if breeding performance during the previous season was related to recent concentrations of seminal NGF in male alpacas (n = 22). Birth rates tended to be correlated with sperm concentration and total amount of NGF in the ejaculate (P = 0.09). Experiment 3 was a prospective study to determine the relationship between seminal NGF (n = 8 male alpacas) and ovulation and pregnancy rates in a breeding trial. No association was detected between seminal NGF concentration and ovulation rate, pregnancy rate, or LH response in the female. We conclude that among the breeding males used in our study, the abundance of seminal NGF was correlated with sperm concentration and thread formation, however, it was not predictive of male fertility in alpacas. Examination of males not previously selected as breeding stock may be expected to include a broader range of seminal NGF and provide a more comprehensive understanding of the relationship between seminal NGF and male fertility.


Assuntos
Camelídeos Americanos , Sêmen , Gravidez , Masculino , Feminino , Animais , Sêmen/fisiologia , Camelídeos Americanos/fisiologia , Fator de Crescimento Neural/metabolismo , Estudos Prospectivos , Estudos Retrospectivos , Fertilidade , Espermatozoides/metabolismo , Motilidade dos Espermatozoides
3.
Reprod Domest Anim ; 58(7): 1005-1011, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37243876

RESUMO

Caspases are crucial mediators of programmed cell death (apoptosis). Apoptosis can occur in spermatozoa during spermatogenesis or epididymal transit, as well as in ejaculated spermatozoa. A high proportion of apoptotic sperm would be a poor indicator of the freezability of a raw seminal sample. Alpaca spermatozoa are notoriously difficult to freeze successfully. Therefore, the objectives of this study were to study caspase activation during incubation (37°C) of fresh alpaca spermatozoa, as well as before and after cryopreservation, to gain some insight into the mechanisms behind the vulnerability of alpaca spermatozoa. Eleven sperm samples were incubated for 4 h at 37°C (Study 1), and 23 samples were frozen using an automated system (Study 2). Caspase-3/7 activation was assessed at 0,1,2,3, and 4 h in samples incubated at 37°C (Study 1); and before/after cryopreservation (Study 2) using CellEvent™ Caspase 3/7 Green Detection Reagent and flow cytometry. The proportions of alpaca spermatozoa with caspase-3/7 activated increased (p < 0.05) after 3-4 h of incubation at 37°C; however, caspase activation was similar before and after cryopreservation (36.2 ± 11.2% vs. 36.6 ± 33.7%, p > 0.05). The high standard deviation found after freezing could be explained by the existence of two subpopulations: one subpopulation where caspase-3/7 activation decreased during cryopreservation (from 36.6 ± 9.1% to 1.5 ± 2.2%), and the other subpopulation where caspase-3/7 activation increased after cryopreservation (from 37.7 ± 13.0% to 64.3 ± 16.7%). In conclusion, after 3-4 h of incubation, caspase-3/7 activation increased in fresh alpaca sperm, whereas cryopreservation affects alpaca sperm samples in different ways.


Assuntos
Camelídeos Americanos , Preservação do Sêmen , Masculino , Animais , Camelídeos Americanos/fisiologia , Caspase 3 , Sêmen/fisiologia , Espermatozoides/fisiologia , Criopreservação/veterinária , Caspases/metabolismo , Preservação do Sêmen/veterinária , Motilidade dos Espermatozoides/fisiologia
4.
Anim Reprod Sci ; 252: 107233, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37079995

RESUMO

The aim of the present study was to evaluate if early administration of progesterone immediately after ovulation affects corpus luteum lifespan in llamas. Female llamas (n = 16) were induced to ovulate by Buserelin injection in the presence of an ovulatory follicle (Day 0). On Day 2, ovulation was confirmed and animals were randomly divided into two groups: treated animals (n = 8) received an intravaginal device containing 0.3 g of progesterone from Day 2 to Day 6 post-induction of ovulation and control group (n = 8) received a device with 0 g of progesterone. Blood samples were collected daily to determine plasma progesterone concentration and transrectal ultrasonographies were performed from Day 7 to Day 12 post-induction of ovulation. Mean maximum diameter of the corpus luteum was significantly lower and was reached before in the treated group than in the control group. The mean highest plasma progesterone concentration and the day that concentration was achieved were similar between groups. However, mean plasma progesterone concentration was significantly higher in the treated group than in the control group on Days 3 and 4 and lower on Days 8 and 9 post-induction of ovulation. The day that plasma progesterone concentration returns to 1 ng/ml differed between groups, occurring earlier in the treated group. In conclusion, the early increase of plasma progesterone concentration during the luteal phase, promoted the premature activation of the luteolytic process affecting corpus luteum function in llamas as it was previously reported in other species.


Assuntos
Camelídeos Americanos , Progesterona , Feminino , Animais , Progesterona/farmacologia , Camelídeos Americanos/fisiologia , Corpo Lúteo/fisiologia , Folículo Ovariano/fisiologia , Ovulação
5.
Gene ; 809: 146018, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34655720

RESUMO

The Agouti gene (ASIP) is one of the most important genes for coat color determination in mammals. It has a complex structure with several promoters and alternative non-coding first exons that are transcribed into mRNAs with different 5'UTR. These mRNA isoforms regulate the temporal and spatial expression of the gene, producing diverse pigmentation patterns. Here, we studied ASIP transcriptional variants and their expression in the skin of llamas with different coat color phenotypes. We also described the ASIP locus, including promoter usage and the splicing events that originate each transcript variant. Using 5'RACE-PCR we isolated seven ASIP transcripts with alternative 5'UTR, where exons 1A, 1A', 1C, 1D, and a novel non-coding exon 1A" were identified. Additionally, new alternative spliced forms were found. The diversity of ASIP 5'UTRs is originated by a complex pattern of alternative promoter usage, multiple transcription start sites and splicing events that include exon skipping and alternative 3' splicing site selection. We found that ASIP was highly expressed in llamas with white and brown phenotypes while black animals presented very low expression. The main responsible for this difference was a fusion transcript between ASIP and NCOA6 genes, which was present in the skin of white and brown llamas but not in the black ones. The rest of ASIP transcripts presented very low expression in the skin, indicating that the main regulation point for ASIP gene expression is at the transcriptional level. Nevertheless, the characteristics of the 5'UTRs sequences suggest that alternative transcripts could be regulated differently at the protein synthesis level.


Assuntos
Regiões 5' não Traduzidas , Proteína Agouti Sinalizadora/genética , Camelídeos Americanos/genética , Pigmentação/genética , Processamento Alternativo , Animais , Camelídeos Americanos/fisiologia , Éxons , Expressão Gênica , Fenótipo , Regiões Promotoras Genéticas , Pigmentação da Pele/genética
6.
Res Vet Sci ; 136: 297-302, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33740564

RESUMO

Auditory loss has been reported in camelids using brainstem auditory evoked responses (BAER). Differentiation between conductive versus sensorineural dysfunction has not been investigated. Therefore, the objective of the study was to investigate auditory function using BAER and bone conduction (BC). Twenty-four alpacas: 15 females, 9 intact males (2-16 years of age) were included in a randomized clinical trial. BAER and BC were recorded using two derivations (vertex to mastoid and vertex to cranial aspect of second cervical vertebra). All alpacas underwent complete physical examinations and were sedated with xylazine hydrochloride at 0.6 mg/kg IM. Peaks, when present, were identified and latencies, amplitudes, and amplitude ratios were determined. Eleven alpacas had normal responses and 13 had auditory loss based on BAER. The latter consisted of complete absence of peaks bilaterally (n = 3), absence of peaks unilaterally (n = 1), delayed latencies bilaterally (n = 4), and delayed latencies unilaterally (n = 5). Distinct peaks on BC supported conductive auditory loss in 6 alpacas, difficult to interpret due to stimulus artifact and additional undefined peaks in 4, and absent peaks in 3 alpacas. The cause of auditory loss was presumed to be due to otitis in 6, aging in 4 (10-16 years old), and congenital sensorineural (absent peaks on BAER and BC) in 3 alpacas with unpigmented fiber and irises. BAER and BC are useful and non-invasive to perform techniques for the investigation of auditory loss in alpacas, and further characterization as conductive or sensorineural.


Assuntos
Condução Óssea/fisiologia , Camelídeos Americanos/fisiologia , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Animais , Feminino , Masculino
7.
Anim Reprod Sci ; 225: 106683, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33388611

RESUMO

The objective of this study was to evaluate effects of dehydration on sperm DNA with the aim of eventually using this method for preserving llama spermatozoa. Two experiments were conducted: 1) sperm preservation at 5 °C for 60 days in different hyperosmotic solutions (500, 800, 1000 and 1200 mOsmol/l) (n = 6, replications = 2) and 2) sperm preservation at 5 and -20 °C for 60 days in the same hyperosmotic solutions, with supplementary antibiotics (n = 6, replications = 2). Sperm motility, membrane functional integrity, viability and morphology were evaluated at 0 and 48 h of the preservation period (Experiment 1) and at 30 min and 24 h (Experiment 2). Sperm DNA was evaluated at 0 or 30 min (Experiment 1 and 2, respectively) and on days 7, 14, 21, 30 and 60 of the preservation periods. Motility, membrane functional integrity and viability were less when sperm were dehydrated, while sperm cell morphology was not affected. There was a smaller percentage of sperm with condensed chromatin as duration of the preservation period increased when stored in the different hyperosmotic solutions. There was a markedly smaller (P < 0.05) percentage of sperm with intact DNA in all solutions as the duration of preservation increased, with there being greater values for intact DNA at -20 °C than sperm preserved at 5 °C. Llama sperm chromatin condensation was slightly affected by the process of dehydration. There was a markedly smaller percentage of sperm with intact DNA in the dehydrated semen samples.


Assuntos
Camelídeos Americanos/fisiologia , Desidratação , Concentração Osmolar , Preservação do Sêmen/veterinária , Espermatozoides/fisiologia , Animais , Sobrevivência Celular , Meios de Cultura , Masculino , Preservação do Sêmen/métodos , Temperatura
8.
Reprod Domest Anim ; 56(4): 680-683, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32979882

RESUMO

The present study examined the effects of different photoperiods and melatonin treatment on plasma prolactin concentrations in guanacos, a South American camelid, in captivity. Fourteen adult female guanacos, not gestating or lactating and isolated from males, were studied. The control group was exposed to natural daylight, during short days (N = 7, 10L:14D) and long days (N = 7, 16L:8D). The treatment group (N = 7, 10L:14D) received melatonin implants every 23 days for 6 weeks during long days. Blood samples were taken at intervals of 1 week for 3 weeks, starting the third week of treatment. Prolactin concentrations were measured using competitive ELISA. Plasma concentrations of prolactin in non-lactating female guanacos have seasonal changes, with a higher concentration (p < .001) in short days (3.50 ± 2.24 ng/ml) than long days (1.10 ± 0.91 ng/ml). Melatonin treatment significantly decreases (p < .05) plasma concentrations of prolactin on the 21st day after the treatment. These findings are the first report of an endogenous circannual rhythm of plasma prolactin concentration and the action of melatonin treatment on prolactin secretion in this wild camelid.


Assuntos
Camelídeos Americanos/fisiologia , Melatonina/farmacologia , Fotoperíodo , Prolactina/sangue , Animais , Implantes de Medicamento , Feminino , Melatonina/administração & dosagem , Estações do Ano
9.
Artigo em Alemão | MEDLINE | ID: mdl-33276409

RESUMO

OBJECTIVE: South American camelids have become popular with an increasing number of breeders in Austria, Germany and Switzerland. The aim of the present online survey was to gain information concerning housing and management of South American camelids, particularly during pregnancy and parturition. MATERIAL AND METHODS: A link to the online survey was sent via email to 8 breeder associations in Austria, Germany and Switzerland. The questionnaire included a total of 24 closed or open questions. The period for participation was May to October 2019. RESULTS: A total of 92 breeders participated and 64 answered all questions. The survey revealed that South American camelids were mainly used for breeding (87 %) and production of fibre (74 %). The median flock size was 27 animals, mainly females. Most breeders (74 %) acquired their knowledge on South American camelids via personal contacts and advanced training courses. The majority (57 %) mated their females with an own sire that is kept separately. Using teaser males was the most popular pregnancy test (91 %), often combined with other techniques, especially ultrasonography. In most mares (88 %) duration of pregnancy was in the normal range of 335-360 days. Repeated problems with loss of pregnancy were reported by 76 % of breeders for less than 5 % of their mares. Postpartum problems occurred sporadically, e. g. lack of milk or mastitis (each < 5 %). Problems with the cria at parturition within the last 3 years were reported by > 50 % of the breeders, but reported reasons for dystocia showed no clear focus. The majority of the participants (69 %) were satisfied with the veterinary care in general and in the fields of pregnancy and obstetrics. CONCLUSION: The results of this survey provide new insights into the management practices of South American camelids breeders in Austria, Germany and Switzerland. Further studies could compare these practices with those in countries where breeding of South American camelids possesses a longer tradition and different commercial backgrounds. CLINICAL RELEVANCE: The results provide information to practitioners in preparation for problems and challenges in the veterinary care of South American camelids.


Assuntos
Criação de Animais Domésticos/estatística & dados numéricos , Cruzamento , Camelídeos Americanos/fisiologia , Animais , Europa (Continente) , Feminino , Masculino , Mastite/veterinária , Gravidez , Inquéritos e Questionários , Medicina Veterinária
10.
Mol Reprod Dev ; 87(11): 1133-1140, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33022130

RESUMO

Copulation produces different stimuli in the female reproductive tract in camelids, which lead to ovulation. Expression of ß-nerve growth factor (ß-NGF) and its specific receptor, tropomyosin receptor kinase A (TrKA), was studied comparing the oviductal microenvironment of mated and nonmated llamas. ß-NGF and TrKA were expressed in the llama ampulla, isthmus, and utero-tubal-junction (UTJ), and they were mainly colocalized in the apical region of the oviductal mucosa. A TrKA immunosignal was also found in muscle cells and blood vessels, with the highest mark in UTJ muscle cells of copulated females. Both ß-NGF and TrKA transcripts were expressed in the three oviductal segments. Relative TrKA abundance did not differ between mated and nonmated females, but relative ß-NGF abundance was higher in the UTJ of copulated females (p < .05). ß-NGF might not be secreted into the oviductal fluid (OF) since the protein was not found in the OF of mated or nonmated females. Therefore, it can be concluded that the llama oviduct expresses the ß-NGF/TrKA system and that an increase in ß-NGF gene expression in the UTJ 24 h after copulation along with an increase in TrKA protein expression may indicate an important role in the gamete transport and fertilization process in llamas.


Assuntos
Camelídeos Americanos/fisiologia , Copulação/fisiologia , Tubas Uterinas/metabolismo , Regulação da Expressão Gênica , Fator de Crescimento Neural/biossíntese , RNA Mensageiro/biossíntese , Receptor trkA/biossíntese , Animais , Líquidos Corporais/metabolismo , Camelídeos Americanos/genética , Feminino , Fator de Crescimento Neural/genética , RNA Mensageiro/genética , Receptor trkA/genética
11.
Anim Reprod Sci ; 223: 106629, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33126045

RESUMO

Artificial insemination would be a useful technique for alpaca breeders to use as an aid to breeding to increase fleece quality. The technique, however, is not well developed in alpacas, partly because of the viscous nature of their seminal plasma. Castration conducted for husbandry purposes can provide a source of epididymal spermatozoa to test semen extenders or handling regimens, thus circumventing the problem of the viscous ejaculate. In this experiment, two semen extenders (Andromed and INRA96) developed for other species (bovine and equine, respectively) were tested with alpaca spermatozoa derived from the cauda epididymis. Sperm total motility (mean ± SEM A: 29.1 ± 4.8 % compared with I: 35.4 ± 4.8 %; NS), membrane integrity (A: 58 ± 9% compared with I: 56 ± 9%; NS) and acrosome integrity (A: 65 ± 7% compared with I: 54 ± 7%; NS) were not different between the two extenders. Progressive motility with use of INRA96 was greater after incubating for 30 min than after incubating for 10 min (35 ± 4% vs. 12 ± 4%, respectively; P = 0.03). In conclusion, viable epididymal spermatozoa could be extracted from the castrated organs after overnight transport. There were no differences in sperm quality between the two extenders; therefore, it appears that either extender could be used for alpaca spermatozoa. These results could help in the development of a technique for artificial insemination in alpacas.


Assuntos
Camelídeos Americanos/fisiologia , Epididimo/citologia , Preservação do Sêmen/veterinária , Sêmen/fisiologia , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/fisiologia , Animais , Criopreservação/veterinária , Processamento de Imagem Assistida por Computador , Inseminação Artificial/veterinária , Masculino , Sêmen/efeitos dos fármacos , Análise do Sêmen/veterinária , Motilidade dos Espermatozoides/fisiologia
12.
Reprod Domest Anim ; 55(9): 1154-1162, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32594592

RESUMO

The objective of this study was to design a protocol to separate spermatozoa from seminal plasma of raw llama semen without prior enzymatic treatment using a single-layer centrifugation with Androcoll-E™ (AE). Two experiments were performed: (a) samples were divided into three aliquots (1 ml) that were deposited on the top of 4, 5 or 6 ml of AE and were centrifuged at 800g for 20 min and (b) samples were divided into two aliquots (1 ml) that were deposited on the top of 4 ml of AE and were centrifuged at 600g or 1,000g for 20 min. Columns of 5 and 6 ml of AE showed a total sperm motility (TM) significantly lower, while in the 4 ml column, this parameter was not different from the TM of samples before the AE treatment. The percentage of spermatozoa with intact and functional membranes, normal morphology and intact acrosomes, as well as the percentages of sperm with highly condensed chromatin, was conserved (p Ëƒ .05) in the three column heights and in the two centrifugation speeds evaluated. In conclusion, the different column heights of AE (4, 5 and 6 ml) and the different centrifugation speeds used (600, 800 and 1,000g) allow separating spermatozoa of raw llama semen without enzymatic treatment, preserving the evaluated sperm characteristics. However, of all the studied treatments, centrifugation in the 4 ml column of AE at 800g would be the method of choice to process raw llama semen samples destined for reproductive biotechnologies.


Assuntos
Camelídeos Americanos/fisiologia , Coloides/farmacologia , Espermatozoides/fisiologia , Acrossomo , Animais , Sobrevivência Celular , Centrifugação/métodos , Centrifugação/veterinária , Masculino , Análise do Sêmen/veterinária , Motilidade dos Espermatozoides
13.
Reprod Domest Anim ; 55(7): 814-821, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32320085

RESUMO

The low fertility and offspring survival indicators in alpacas can be partially due to their particularity seasonal reproduction that reduces the opportunities of the females to become pregnant within a season, with the survival of the offspring concerned by the availability of food and exposure to diseases that depends on the calving date. Optimizing the date of delivery and reducing its variability are shown as eligible criteria that could be used as selection criteria within the genetic improvement programmes in alpacas, the calving date being a much more appropriate trait to measure and optimize fertility unlike of age at first calving and the calving interval, this due to the reproductive seasonality in camelids. For this study, 6,533 birth date records were taken between 2001 and 2018 of Peruvian alpacas, to estimate the genetic parameters. Models assuming heterogeneity in the residuals were fitted besides classical homogeneous models to address, not only the possibility of forwarding or delaying the calving date, but also the trend to have parturitions in similar dates. The heritability and repeatability ranged from 0.07 to 0.20 for a homogeneity model and from 0.08 to 0.23 for a heterogeneity model, and suggest the possibility of advancing or delaying the calving date. It should be taken into account that the gestation length of camelids makes it difficult to adapt many reproductive traits, and trying to centre the calving date could delay it. It was concluded the feasibility to genetically select the calving date, also in the production of camels and dromedaries, which have the same reproductive characteristics as alpacas. This selection can be combined with other traits. The heterogeneity model was shown to provide a better fit.


Assuntos
Camelídeos Americanos/fisiologia , Parto/fisiologia , Animais , Cruzamento , Camelídeos Americanos/genética , Feminino , Parto/genética , Peru , Gravidez , Reprodução/genética , Reprodução/fisiologia , Estações do Ano
14.
Vet Rec ; 186(16): e7, 2020 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-32303669

RESUMO

BACKGROUND: Alpacas are being more frequently presented to veterinarians in the UK. It is important to validate whether published normal ocular parameters are consistent with the alpaca population in the UK. METHODS: Ophthalmic examinations were performed on healthy alpacas (Vicugna pacos) from three farms in East Anglia, UK. RESULTS: On direct ophthalmoscopy of 35 alpacas, there was a 50 per cent prevalence of opacities within the lens in alpacas older than two years old (n=8/16). There was a 36.8 per cent prevalence of persistent hyaloid arteries in alpacas under two years old (n=7/19). The mean Schirmer tear test-1 value was 20.0 ±6 mm/minute (n=40). The mean intraocular pressure measured by rebound tonometry was 17.2 ±5.5 mmHg (n=46), and applanation tonometry resulted in statistically similar values (P=0.30; n=25). There was a significant variation in intraocular pressure throughout a 24-hour period (n=8). Fluorescein dye was not detected at the nostrils of any of the alpacas which underwent a Jones test to assess nasolacrimal duct patency (n=8). CONCLUSION: The ophthalmic findings appear largely consistent with previously published values from North America and continental Europe. Variations include the large range of measurements obtained and evidence of diurnal variation in intraocular pressure.


Assuntos
Camelídeos Americanos/fisiologia , Pressão Intraocular/fisiologia , Tonometria Ocular/veterinária , Animais , Estudos Transversais , Feminino , Masculino , Valores de Referência , Reprodutibilidade dos Testes , Reino Unido
15.
Biol Reprod ; 103(1): 49-59, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32307518

RESUMO

Kisspeptin has been implicated in the ovulatory process of several species of spontaneous ovulators but in only one induced ovulator. In contrast, NGF in semen is the principal trigger of ovulation in other species of induced ovulators-camelids. We tested the hypotheses that kisspeptin induces luteinizing hormone (LH) secretion in llamas through a hypothalamic mechanism, and kisspeptin neurons are the target of NGF in its ovulation-inducing pathway. In Experiment 1, llamas were given either NGF, kisspeptin, or saline intravenously, and LH secretion and ovulation were compared among groups. All llamas treated with NGF (5/5) or kisspeptin (5/5) had an elevation of LH blood concentrations after treatment and ovulated, whereas none of the saline group did (0/5). In Experiment 2, llamas were either pretreated with a gonadotropin-releasing hormone (GnRH) receptor antagonist or saline and treated 2 h later with kisspeptin. Llamas pretreated with saline had elevated plasma LH concentrations and ovulated (6/6) whereas llamas pretreated with cetrorelix did not (0/6). In Experiment 3, we evaluated the hypothalamic kisspeptin-GnRH neuronal network by immunohistochemistry. Kisspeptin neurons were detected in the arcuate nucleus, the preoptic area, and the anterior hypothalamus, establishing synaptic contacts with GnRH neurons. We found no colocalization between kisspeptin and NGF receptors by double immunofluorescence. Functional and morphological findings support the concept that kisspeptin is a mediator of the LH secretory pathway in llamas; however, the role of kisspeptins in the NGF ovulation-inducing pathway in camelids remains unclear since NGF receptors were not detected in kisspeptin neurons in the hypothalamus.


Assuntos
Camelídeos Americanos/fisiologia , Kisspeptinas/farmacologia , Hormônio Luteinizante/metabolismo , Indução da Ovulação/veterinária , Ovulação/efeitos dos fármacos , Ovulação/fisiologia , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/química , Kisspeptinas/análise , Kisspeptinas/fisiologia , Masculino , Fator de Crescimento Neural/isolamento & purificação , Fator de Crescimento Neural/farmacologia , Neurônios/química , Receptores de Fator de Crescimento Neural/análise , Sêmen/química
16.
Sci Rep ; 10(1): 3856, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32123239

RESUMO

From the camel's toes to the horse's hooves, the diversity in foot morphology among mammals is striking. One distinguishing feature is the presence of fat pads, which may play a role in reducing foot pressures, or may be related to habitat specialization. The camelid family provides a useful paradigm to explore this as within this phylogenetically constrained group we see prominent (camels) and greatly reduced (alpacas) fat pads. We found similar scaling of vertical ground reaction force with body mass, but camels had larger foot contact areas, which increased with velocity, unlike alpacas, meaning camels had relatively lower foot pressures. Further, variation between specific regions under the foot was greater in alpacas than camels. Together, these results provide strong evidence for the role of fat pads in reducing relative peak locomotor foot pressures, suggesting that the fat pad role in habitat specialization remains difficult to disentangle.


Assuntos
Camelídeos Americanos/fisiologia , Camelus/fisiologia , Pé/fisiologia , Caminhada/fisiologia , Animais , Humanos , Pressão
17.
Theriogenology ; 150: 280-287, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32088046

RESUMO

The ovulation-inducing effect of seminal plasma was first suggested in Bactrian camels over 30 years ago, initiating a long search to identify the 'ovulation-inducing factor' (OIF) present in camelids semen. During the last decade, primarily in llamas and alpacas, this molecule has been intensively studied characterizing its biological and chemical properties and ultimately identifying it as ß-Nerve Growth Factor (ß-NGF). The high concentration of OIF/ß-NGF in seminal plasma of llamas and alpacas, and the striking effects of seminal fluid on ovarian function strongly support the notion of an endocrine mode of action. Also, have challenged the dogma of mating induced ovulation in camelid species, questioning the classical definition of reflex ovulators, which at the light of new evidence should be revised and updated. On the other hand, the presence of OIF/ß-NGF and its ovulatory effect in camelids confirm the notion that seminal plasma is not only a transport and survival medium for sperm but also, a signaling agent targeting female tissues after insemination, generating relevant physiological and reproductive consequences. The presence of this molecule, conserved among induced as well as spontaneous ovulating species, clearly suggests that the potential impacts of this reproductive feature extend beyond the camelid species and may have broad implications in mammalian fertility. The aim of the present review is to provide a brief summary of all research efforts undertaken to isolate and identify the ovulation inducing factor present in the seminal plasma of camelids. Also to give an update of the current understanding of the mechanism of action of seminal ß-NGF, at central and ovarian level; finally suggesting possible brain targets for this molecule.


Assuntos
Camelídeos Americanos/fisiologia , Fator de Crescimento Neural/metabolismo , Ovulação/fisiologia , Animais , Feminino , Masculino , Sêmen
18.
Reprod Domest Anim ; 55(1): 74-80, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31737943

RESUMO

The aim of this study was to characterize corpus luteum vascularization and its association with plasma progesterone concentration in early stages of pregnancy, when maternal recognition of pregnancy is expected to occur. In all animals, both plasma progesterone concentration and corpus luteum vascularization increased from Day 6 to Day 8 post-mating and afterwards in non-pregnant llamas they started to decrease to reach basal levels around Days 12 to 14 post-mating, while in pregnant animals, both variables remained elevated until the end of the study. A lineal positive relationship between corpus luteum vascularization and plasma progesterone concentration was observed in pregnant (r2  = .46, p < .0001) and non-pregnant llamas (r2  = .66, p < .0001). Pregnant animals showed higher plasma progesterone concentration and corpus luteum vascularization than the non-pregnant ones from Day 12 post-mating until the end of the study (p Ë‚ .05 and p Ë‚ .01, respectively). These results suggest that maternal recognition of pregnancy should occur before Day 12 post-mating in order to expand luteal lifespan, maintaining corpus luteum vascularization and progesterone production. Also, the assessment of CL vascularization area could be a useful and non-invasive method for early pregnancy diagnosis due to its association with plasma progesterone concentration.


Assuntos
Camelídeos Americanos/fisiologia , Corpo Lúteo/irrigação sanguínea , Progesterona/sangue , Animais , Corpo Lúteo/fisiologia , Feminino , Masculino , Ovário/diagnóstico por imagem , Gravidez , Ultrassonografia/veterinária
19.
Sensors (Basel) ; 19(24)2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31835550

RESUMO

Monitoring the cardiopulmonary signal of animals is a challenge for veterinarians in conditions when contact with a conscious animal is inconvenient, difficult, damaging, distressing or dangerous to personnel or the animal subject. In this pilot study, we demonstrate a computer vision-based system and use examples of exotic, untamed species to demonstrate this means to extract the cardiopulmonary signal. Subject animals included the following species: Giant panda (Ailuropoda melanoleuca), African lions (Panthera leo), Sumatran tiger (Panthera tigris sumatrae), koala (Phascolarctos cinereus), red kangaroo (Macropus rufus), alpaca (Vicugna pacos), little blue penguin (Eudyptula minor), Sumatran orangutan (Pongo abelii) and Hamadryas baboon (Papio hamadryas). The study was done without need for restriction, fixation, contact or disruption of the daily routine of the subjects. The pilot system extracts the signal from the abdominal-thoracic region, where cardiopulmonary activity is most likely to be visible using image sequences captured by a digital camera. The results show motion on the body surface of the subjects that is characteristic of cardiopulmonary activity and is likely to be useful to estimate physiological parameters (pulse rate and breathing rate) of animals without any physical contact. The results of the study suggest that a fully controlled study against conventional physiological monitoring equipment is ethically warranted, which may lead to a novel approach to non-contact physiological monitoring and remotely sensed health assessment of animals. The method shows promise for applications in veterinary practice, conservation and game management, animal welfare and zoological and behavioral studies.


Assuntos
Abdome/fisiologia , Fenômenos Fisiológicos Cardiovasculares , Monitorização Fisiológica , Gravação em Vídeo/métodos , Abdome/diagnóstico por imagem , Animais , Camelídeos Americanos/fisiologia , Sistema Cardiovascular/diagnóstico por imagem , Hospitais Veterinários , Humanos , Leões/fisiologia , Macropodidae/fisiologia , Papio/fisiologia , Phascolarctidae/fisiologia , Projetos Piloto , Spheniscidae/fisiologia , Tigres/fisiologia , Ursidae/fisiologia
20.
Sci Rep ; 9(1): 12826, 2019 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-31492923

RESUMO

This study compared protocols for cryopreservation of ejaculated, papain-treated alpaca spermatozoa. This included different concentrations of egg yolk (EY; 5, 10 or 15%) and glycerol (2, 5 or 10%), diluent types (SHOTOR, lactose, skim milk or INRA-96™), freeze rates (2, 4 or 8 cm above liquid nitrogen; LN), thaw rates (37 °C for 1 min or 42 °C for 20 sec) and storage vessels (pellets, 0.25 mL straws or 0.5 mL straws). Spermatozoa were assessed pre-freeze and 0, 30, 60 and 90 min post-thaw. Forty-one hembras were inseminated with either fresh, papain-treated or frozen-thawed spermatozoa. Motility was affected by EY concentration (P < 0.001), diluent type (P < 0.001), freeze rate (P = 0.003) and storage vessel (P = 0.001). Viability was affected by EY concentration (P < 0.001), diluent type (P < 0.001), storage vessel (P = 0.002) and thaw rate (P = 0.03). For artificial insemination (AI), semen was diluted 1:3 in a lactose-based diluent, with 5% EY and glycerol. Freezing was in 0.5 mL straws, 2 cm above LN for 4 min then thawing at 37 °C for 1 min. Pregnancy rates of those ovulated (n = 26) were not different (1/5 fresh, 1/4 papain-treated, 0/17 frozen-thawed; P = 0.10). Pregnancy can be achieved after AI with papain-treated spermatozoa. Further work is needed to determine the optimal dose, timing and location for insemination.


Assuntos
Camelídeos Americanos/fisiologia , Criopreservação , Crioprotetores/farmacologia , Fertilidade/efeitos dos fármacos , Congelamento , Espermatozoides/fisiologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Gema de Ovo/metabolismo , Feminino , Glicerol/farmacologia , Inseminação Artificial , Masculino , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos
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