DigitalUM :: Browsing by Subject "Sheep"

Browsing by Subject "Sheep"

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A time-resolved fluorescence immunoassay for the detection of anti-Neospora caninum antibodies in sheep
(Elsevier, 2019-11-18) Huertas López, Ana; Huertas-López, Ana; Martínez-Carrasco Pleite, Carlos; Cerón Madrigal, José Joaquín; Sánchez-Sánchez, Roberto; Vázquez-Calvo, Ángela; Álvarez-García, Gema; Martínez Subiela, Silvia; Sanidad Animal; Facultad de Veterinaria
Neospora caninum is a protozoan parasite (Phylum Apicomplexa) that has been recently suggested as a relevant cause of reproductive disorders in small ruminants. The aim of the present study is to develop and validate a new serological test based on time resolved fluorescency using N. caninum GRA7 recombinant antigen (GRA7-TRFIA) for the detection of N. caninum antibodies in sheep. A total of 346 serum samples (208 from experimentally infected sheep, 117 from a dairy farm with a previous history of Neospora-associated abortion, and 21 negative sera) were used. The validation of the new assay was performed by the evaluation of assay precision, analytical sensitivity (Se), accuracy and cross reactivity. In the experimentally infected sheep, antibody kinetics was compared between GRA7-TRFIA and an in house N. caninum tachyzoite soluble extract-based ELISA (NcSALUVET ELISA) by Wilcoxon matched-pairs signed rank test. The cut-off and diagnostic Se and specificity (Sp) of GRA7-TRFIA was estimated by ROC analysis with field samples. In addition, concordance and correlation between GRA7-TRFIA and a commercial ELISA and NcSALUVET ELISA were assessed by kappa value and Spearman correlation coefficient, respectively. Overall, GRA7-TRFIA showed an adequate precision, analytical Se and accuracy to detect anti-N. caninum antibodies in ovine serum, and no cross reactivity with the closely related protozoan Toxoplasma gondii. In naturally infected sheep, 100% Se and 95.35% Sp were obtained for a cut-off point of 62.68 Units of Fluorometry for N. caninum (UFN). Moreover, GRA7-TRFIA allowed earlier detection of N. caninum infection than NcSALUVET ELISA in experimentally infected sheep.
Open Access
Antimicrobial Susceptibility of Isolated from Sheep with Fibrinous Pneumonia
(Sciendo, 2023-07-01) Galecio, Juan Sebastián; Badillo, Elena; Escudero, Elisa; Corrales, Juan Carlos; Yuste Pérez, María Teresa; Marín, Pedro; Farmacología
Ovine respiratory complex is a signifi cant cause of death in sheep fl ocks, where Pasteurella multocida is the most frequent microorganisms isolated from animals with pneumonia. There is an urgent need to refi ne the use of different antimicrobials to avoid the problem of antimicrobial resistance and optimize the control of this disease in ovine livestock. The fi rst step in approaching this problem is gaining an insight into the antimicrobial susceptibility of ovine pathogens. This study evaluated the in vitro activity of tildipirosin, gamithromycin, oxytetracycline, and danofl oxacin against Pasteurella multocida strains isolated from sheep with fi brinous pneumonia. The strains were incubated following Clinical and Laboratory Standards Institute (CLSI) standard conditions and also with a modifi ed method by 25% supplementation with sheep serum. Minimum inhibitory concentrations (MIC) were determined using the broth microdilution technique. The lowest MIC90 under standard conditions and by supplementation with sheep serum was obtained with tildipirosin. Sheep serum signifi cantly reduced tildipirosin, gamithromycin, and danofl oxacin MIC values for Pasteurella multocida strains. In brief, the potency of tildipirosine, gamithromycin, and danofl oxacin against Pasteurella multocida increases when sheep serum is added to the culture media.
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Biomarkers of oxidative stress in saliva of sheep: Analytical performance and changes after an experimentally induced stress
(Elsevier, 2019-04) Peres Rubio, Camila; Contreras-Aguilar, Maria Dolores; Quiles, A.; López-Arjona, Marina; Cerón, J.J.; Martínez-Subiela, Silvia; Hevia, M.L.; Escribano Tortosa, Damián; Tecles, Fernando; Medicina y Cirugía Animal
Oxidative stress can affect animal's health and the quality of its final products. The oxidative status can be evaluated by the measurement of both oxidant and antioxidant biomarkers. The use of saliva as a sample is preferable to blood, as individuals with limited training can collect it easily and non-invasively with minimal stress to the animal. The aim of this study was to perform an analytical validation of automated assays of the ferric reducing ability of plasma (FRAP), the cupric reducing antioxidant capacity (CUPRAC), the Trolox equivalent antioxidant capacity (TEAC) and uric acid as antioxidant biomarkers and of the advanced oxidation protein products (AOPP) and hydrogen peroxide (H2O2) as oxidant biomarkers in saliva samples of sheep, and to evaluate their possible changes after stress induced by shearing. All assays produced acceptable results in the analytical validation, from which it can be concluded that oxidative stress biomarkers such as FRAP, CUPRAC, TEAC, uric acid and AOPP and H2O2 can be measured in sheep saliva. In addition, acute stress due to shearing could produce an oxidative stress response in sheep and subsequently increase antioxidants in order to protect cells from damage.
Open Access
Bone allograft non-union is related to excessive osteoclastic bone resorption: A sheep model study
(Murcia : F. Hernández, 2006) Laird, R.K.; Pavlos, N.J.; Xu, J.; Brankov, B.; White, B.; Fan, Y.; Papadimitriou, J.M.; Wood, D.J.; Zheng, M.H.
Using a sheep femoral allograft model we have investigated the cellular and molecular mechanisms associated with non-union of bone allografts. Histomorphometric analysis revealed that allograft nonunions featured both marked increases in osteoclast (OC) numbers and total eroded bone surface as compared to allografts wich had undergone direct union. Three distinct cellular layers lying adjacent to the allograft bone surface were identified in all non-union cases. The outer or fibroblastic layer contained an abundance of fibroblasts and connective tissue. Circumscribing this layer was a band of synovial-like cells consisting mainly of large spindle-shaped mononuclear cells mixed with scattered round-shaped mononuclear cells. The third layer, which was directly juxtaposed to the allograft bone surface, consisted predominantly of multinuclear OCs which were positively identified by calcitonin receptor immunohistochemistry. Interestingly, in-situ hybridisation revealed that surrounding synovial-like cells in non-union allografts, expressed abundant gene transcripts for receptor activator NF-kB ligand (RANKL), a membrane bound factor critical for both the induction of OC activity and osteoclastogenesis. We propose that excessive bone resorption by host OCs contributes, at least partially, to the failure of bone allografts. The production of RANKL by synovial-like fibroblasts may be the driving force responsible for the elevated generation and activation of OCs. Based on such evidence novel therapeutic strategies for the treatment of non-union bone allografts using anti-bone resorbing agents may be devised.
Open Access
Day-night changes in plasma melatonin levels, synaptophysin expression and ultrastructural properties of pinealocytes in developing female sheep under natural long and short photoperiods
(Murcia : F. Hernández, 2003) Redondo, E.; Regodón, S.; Franco, A.; Masot, A.J.; Gázquez, A.; Cardinali, D.P.
The aim of the present study was to analyze the 24-h rhythm in plasma melatonin concentration and the day-night differences in synaptophysin expresion and ultrastructural characteristics of the pinealocytes in developing female sheep. Ewes of three different ages were examined: infantile (1-6 months old), pubertal and early fertile age (9-24 months old) and adult (36-60 months old). Experiments were conducted under natural non-stimulatory (long) and stimulatory (short) photoperiods. The obtained results were similar for both analyzed photoperiods. Plasma melatonin concentration, measured in samples obtained every 4 h, showed a similar pattern in the three age groups, with peak values at 02:00 h and troughs at 14:00 h. Mean value of plasma melatonin levels in 9-24 month-old sheep was significantly greater than that in younger or older sheep. The weight of pineal glands obtained at night (02:00 h) was significantly higher than in daylight (14:00 h). Pubertal and early fertile sheep had the largest pineal glands. The pineal volume, and the total number of pinealocytes per gland of 9-24 months-old sheep differed significantly from that of younger or older sheep. The pineal volume, and the mean volume of pinealocytes was significantly greater in animals killed at night. Number of pinealocytes did not vary between animals killed during daylight or at night. The mean volumen of pinealocytes did not show statistical differences between the age groups. In quantitative ultrastructural analysis of pinealocyte cells, the relative volume of mitochondria, rough endoplasmic reticulum and Golgi complexes was significantly greater in 9-24 month-old sheep and in animals killed at night. The relative volume of lipid droplets was highest in older sheep. Collectively, the data support the existence of developmental changes in pinealocyte morphology and quantity, partially in coincidence with a higher melatonin secretion rate.
Open Access
Detection of anti-Neospora caninum antibodies in sheep’s full-cream milk by time-resolved fluorescence immunoassay
(Elsevier, 2021-12-25) Huertas-López, Ana; Sánchez-Sánchez, Roberto; Diezma-Díaz, Carlos; Alvarez-García, Gema; Martínez-Carrasco Pleite, Carlos; Martínez Subiela, Silvia; Cerón Madrigal, José Joaquín; Sanidad Animal; Facultad de Veterinaria
Ovine neosporosis, caused by the Apicomplexan parasite Neospora caninum, leads to reproductive failure worldwide. Nowadays, there is a trend to develop diagnostic techniques using non-invasive samples, such as milk, in order to reduce animal stress, sample collection effort, and costs. The objective of this study was to develop and validate a highly sensitive and specific serological technique, based on a time resolved-fluorescence immunoassay using a N. caninum GRA7 antigen (GRA7-TRFIA), for the detection of anti-N. caninum immunoglobulins G on sheep’ full-cream milk samples. An analytical validation was performed, including intra- and inter-assay precision, analytical sensitivity and accuracy. The diagnostic performance of the assay was evaluated by studying the positive-negative discrimination by Mann Whitney U tests. In additon optimal cut-offs, diagnostic sensitivity and specificity, and areas under the curve were calculated by three Receiver Operating Curve (ROC) analyses, using GRA7-TRFIA and a N. caninum tachyzoite soluble extract-based ELISA (NcSALUVET-ELISA) in blood sera, and the coinciding results of both techniques, as reference techniques. Moreover, Spearman’s correlation of GRA7-TRFIA in milk with the techniques in sera and agreement (kappa values) were also estimated. GRA7-TRFIA for milk samples showed an adequate precision, with high analytical sensitivity and accuracy. Regarding ROC analyses, at the optimal cut-offs, the diagnostic sensitivity and specificity were more than 90 % in all cases. In addition, GRA7-TRFIA values in milk were more positively correlated to GRA7-TRFIA values in blood sera than in the case of values obtained with NcSALUVET-ELISA. GRA7-TRFIA in milk showed an almost perfect agreement with GRA7-TRFIA in blood sera (kappa = 0.98) and with the coinciding results of GRA7-TRFIA and NcSALUVET in blood sera (kappa = 1.00), while it has a substantial agreement with NcSALUVET-ELISA (kappa = 0.69). In the light of these results, GRA7-TRFIA in full-cream milk samples is a highly sensitive technique that could be used for screening anti-N. caninum antibodies in sheep flocks.
Open Access
Disposition kinetics and bioavailability of doxycycline after parenteral administrations in ewes
(Elsevier, 2024-09-10) Martínez, José; Escudero Pastor, Elisa; Badillo Puerta, Elena; Yuste Pérez, María Teresa; Galecio Naranjo, Juan Sebastian; Marín Carrillo, Pedro; Farmacología
Doxycycline is a tetracycline, which have been marketed in different species for treating infections caused by susceptible bacteria. There is limited information on the disposition kinetics of this drug in ewes and this antimicrobial may be useful against several sheep pathogens that are common causes of morbidity and economic loss. Therefore, the aim of this work was to establish the pharmacokinetics of doxycycline after intravenous (IV) and extravascular (subcutaneous (SC) and intramuscular (IM)) administrations in this species. A cross-over model was designed (n = 6). Doxycycline was dosed at 5 mg/kg for IV administration and 20 mg/kg for extravascular administrations. Non-compartmental pharmacokinetic methods were used to calculate plasma concentration-time data. The value of apparent volume of distribution (Vz) suggests a moderate distribution of this antibiotic in sheep, with a value of 0.84 L/kg. The maximum concentrations achieved after extravascular administrations (Cmax) were similar, with no significant differences between the two routes of administration (IM and SC). However, doxycycline absorption was slower after SC administration than after IM administration, taking twice as long to reach maximum plasma concentration (tmax). Bioavailabilities after extravascular routes of administration were low and after IM administration doxycycline caused lameness in all animals. Therefore, the SC administration showed a better profile with respect to pharmacokinetic properties and safety. Future studies on the susceptibility of isolated sheep pathogens to doxycycline are needed to establish appropriate dosing regimens.
Open Access
Evaluation of the efficacy of a new commercially available inactivated vaccine against ovine enzootic abortion
(Frontiers Media, 2020-09-04) Montbrau, Carlos; Fontseca, Mireia; March, Ricard; Sitja, Marta; Benavides, Julio; Caro, María Rosa; Salinas Lorente, Jesús; Ortega Hernández, Nieves; Sanidad Animal
Ovine enzootic abortion (OEA), caused by Chlamydia abortus, is an economically important disease inmany countries. Inactivated vaccines have been used formany years as they induce immunity in sheep, although outbreaks of abortions have been described in vaccinated flocks. In addition, there is a commercially available live attenuated vaccine that provides good protective results. Recently however, reports question the attenuation of this vaccine and associate it with the appearance of outbreaks of OEA in vaccinated flocks. In the present study, a recently commercialized inactivated vaccine (INMEVA®; Laboratorios Hipra S.A., Amer, Spain) has been evaluated using mouse and sheep experimental models. In the mouse models (non-pregnant and pregnant models), the efficacy of INMEVA vaccine has been compared to an unvaccinated control group and to an experimental inactivated vaccine considered as a positive protection control (UMU vaccine). In the non- pregnant model, the UMU vaccine was more effective than the INMEVA vaccine regarding the impact on body weight or the presence of C. abortus in the liver, but both vaccinated groups (UMU and INMEVA) had significantly lower C. abortus in the liver compared to the control group. In the pregnant model in terms of reproductive failures, pups per mouse or the presence of C. abortus in the liver or uterus, no significant differences were found between both vaccines, inducing protection compared to the control group. In the ovine pregnant model, where INMEVA vaccine was compared only to an unvaccinated group, the results indicate that this new commercial vaccine is safe and provides a suitable level of protection against an experimental challenge with C. abortus. A 75% reduction in reproductive disorders, 55% reduction in animals with C. abortus shedding on day of parturition/abortion, and a significant reduction of the average amount of chlamydial shedding from parturition/abortion over the next 21 days was observed, in relation to the infected control group. The results suggest that this vaccine is adequate for the control and prevention of OEA; however, future studies are necessary to elucidate the type of protective immune response that it induces.
Open Access
Expression of keratin 19, Na-K-Cl cotransporter and estrogen receptor alpha in developing mammary glands of ewes
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Colitti, M.
Mammary gland remodelling is strictly related to intracellular signals and stem cell biology. Among the best candidates to identify the nature and development of mammary cells are cytokeratin 19 (CK19), the Na-K-Cl cotransporter (NKCC1) and receptor of estrogen alpha (ERα). In this study, we analyzed the expression of these genes in ewe mammary glands from prepubertal stage to involution. Using Real time PCR we showed that NKCC1 transcription was significantly down regulated during lactation and at involution in comparison to the expression measured in the prepubertal group. No significant differences were found in CK19 expression, whereas ERα transcription was significantly down regulated before lambing, during lactation and at involution. In situ hybridization analysis confirmed quantitative data and localized the CK 19 transcript at basal and luminal compartment of terminal ductal unit (TDU) of prepubertal mammary glands. NKCC1 expression was also present in lactating glands and ERα in connective tissue surrounding TDU. The characterization and identification of mammary developmental markers in the tissue of dairy animals is necessary to gain knowledge in mammary gland biology.
Open Access
First report of Marshallagia dentispicularis from sheep in Europe
(Springer, 2004) Garijo Toledo, M. Magdalena; Ortiz, Juana; Alonso de Vega, Francisco; Ruiz de Ybáñez Carnero, María del Rocío; Sanidad Animal
During post mortem examination of 181 sheep, a total of 16 male and 26 female nematodes were identified as Marshallagia dentispicularis. This is the first report of the parasite in European sheep. A complete description of the species is given.
Open Access
Histochemical localization of glycosaminoglycans in the omasal papillae of sheep
(Murcia : F. Hernández, 1993) Yamamoto, Y.; Kitamura, N.; Yamada, J.; Yamashita, T.
Histochemical localization of the glycosaminoglycans in the omasal laminae were examined at light and electron microscopic levels. The core region of the omasal papillae was stained strongly with alcian blue at pH 2.5 and 1.0. The staining was degraded moderately and completely when tissue sections were pretreated with mild and active methylation, respectively. Alcianophilia was moderately decreased with saponification. Furthermore, enzymatic digestion procedures showed that these alcianophilic substances contained a large amount of hyaluronic acid and chondroitin sulphate. Ultrastructurally, a spider weblike structure was widely distributed among the spindleshaped fibroblast-like cells and fibrous networks of collagen and elastin. These results suggest that the core region of the omasal papillae not only acts as a physical buffer resisting the local pressure from the lumen, but may also influence material transport through the omasal mucosa.
Open Access
Histomorphometric analysis of the reticulum of the sheep during development
(Murcia : F. Hernández, 1993) Franco, A.; Robina, A.; Regodón, S.; Vivo, J.M.; Masot, A.J.; Redondo, E.
Histomorphometric and scanning electron microscopic analysis were performed on 74 embryos and foetuses and on 20 sheep (early post-natal to adult age). Histodifferentiation of the reticulum took place at 33 days of foetal life. Reticular ribs were observed as evaginations of the epithelial stratum germinativum at 64 days. Neutral mucopolysaccharides first appeared in epithelial cells at 46 foetal days, thereafter to decrease gradually in number, subsequently stabilising in postnatal life. Acid mucopolysaccharides, mucins and mucoid compounds were not detected. Growth curves and formulae were constructed for each tissue layer. Initial test involved multiplicative (y=axb), linear (y=a+bx) and polynomial model (y=a+bx+cx2+dx3).
Open Access
In Vitro Interaction between Mycoplasma agalactiae and Small Ruminants’ Endogenous Bacterial Strains of Enterococcus spp. and Coagulase-Negative Staphylococcus
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-02-17) Toquet, Marion; Bataller, Esther; Toledo Perona, Raquel; Gomis, Jjesús; Contreras de Vera, Antonio; Sánchez, Antonio; Jiménez Trigos, Estrella; Gómez Martín, Ángel; Sanidad Animal
Recently, an antimicrobial effect on Mycoplasma agalactiae (Ma), the main etiological agent of contagious agalactia (CA), was reported in vitro with strains of Enterococcus spp. from ovine and caprine milk. The aim of this work was to evaluate the interaction of Ma with the same Enterococcus spp. isolated from other anatomical locations (vagina) and other bacterial populations present in milk, such as coagulase-negative staphylococci (CNS). The vaginal Enterococcus strains and the raw milk CNS were isolated from sheep and goats. Experimental in vitro conditions were prepared to assess the growth of Ma with and without the presence of these strains. The selected vaginal strains were identified as Enterococcus (E.) hirae and E. mundtii, and the strains of CNS were identified as Staphylococcus petrasii. Different interactions of Ma with ovine and caprine wild vaginal strains of Enterococcus and dairy strains of CNS are described for the first time: Ma can grow exponentially during 15 h with the selected strains, although with certain strains, its optimal growth can be negatively affected (p< 0.05). The colonization and/or excretion of Ma could, therefore, be influenced by certain endogenous bacterial strains. Our results increase the knowledge about possible bacterial ecology dynamics surrounding CA.
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Kinetics of infection and effects on the placenta of Chlamydophila abortus in experimentally infected pregnant ewes
(SAGE Publications, 2004-09-01) García de la Fuente, J. N.; Sánchez, J.; Gutiérrez Martín, C. B.; Rodríguez Ferri, E. F.; Salinas, J.; Martínez Cáceres, Carlos Manuel; Navarro Cámara, José Antonio; Ortega Hernández, Nieves; Buendía Marín, Antonio Julián; Anatomía y Anatomía Patológica Comparadas
A Chlamydophila abortus-induced abortion model was carried out on the basis of the experimental infection of ewes at day 75 of gestation. The infection induced abortions and the birth of weak lambs during the last 3 weeks of pregnancy. To study the kinetics of the infection in the placenta and in other organs, infected ewes were killed at 105, 120, and 130 days of gestation and also several days after abortion or parturition. Infected ewes developed a systemic infection that caused a mild and transient pneumonia and focal hepatitis. Pathologic changes were observed in placentas at 120 day of gestation, although the lesions varied between animals and even between placentomes of the same placenta. The first placental area infected was the maternal stroma and epithelium next to the intercaruncular areas, where neutrophilic response seemed to control the infection. A substantial degree of multiplication of C. abortus was then observed in the trophoblast cells of the placentome, periplacentomal choriallantoic membranes, and hilius, with an inflammatory exudate composed mainly of neutrophils, some macrophages, and very scarce lymphocytes. After abortion, the lesions affected the intercotyledonary areas of the aborted placentas, whereas in the uterus significant lymphocyte infiltration was observed, together with a rapid decrease of the C. abortus antigen in the degenerated caruncular tissues.
Open Access
Localization of serotonin, cholecystokinin and somatostatin immunoreactivity in the lower respiratory tract of embryonic, foetal and postnatal sheep
(Murcia : F. Hernández, 1992) Balaguer, L.; Romano, J.; Ruíz-Pesini, P.
The lower respiratory tract of the sheep was studied by light-microscopical immunocytochemistry for serotonin, cholecystokinin, somatostatin, bombesin and calcitonin during different periods of lung development; embryonic, foetal and postnatal. At embryonic period only intraepithelial serotonin-containing cells as solitary neuroendocrine cells (NEC) and neuroepithelial bodies (NEB) were found. At foetal stages, immunoreactive cells to serotonin, cholecystokinin and somatostatin were observed in airway epithelium, as solitary NEC and NEBs, and in autonomic intrapulmonary ganglia as single or clusters of small intensely-fluorescent (SIF) cells. In postnatal sheep, serotonin- and cholecystokinincontaining cells were found within airway mucosa as solitary NECs and NEBs. No immunoreactive cells were observed with antiserum to bombesin and calcitonin. Quantitative studies showed that serotonin was the predominant substance, and that solitary neuroendocrine cells were more numerous in dista1 conducting airways and at foetal stages
Open Access
Metabarcoding analysis of the microbiota in flocks naturally infected by Coxiella burnetii: First description of the global microbiota in domestic small ruminants
(Elsevier, 2025-06) Contreras de Vera, Antonio; Sanidad Animal
This study investigates Q fever in sheep and goats, key reservoirs for human infection, by metabarcoding and comparing it with q-PCR and serology. Samples from 26 small ruminant (aborted and normal-delivery) and six males across three Q fever-affected herds were analyzed. In sheep herds, seropositivity was 50 and 80% respectively, with Coxiella (C.) burnetii shedding detected vaginally in the second herd. In goats, 100% seropositivity and 90% C. burnetii detection were observed, with nasal and vaginal samples showing the highest detection rates. Metabarcoding revealed significant differences in alpha diversity, with greater richness in blood and evenness in milk from normal-delivery sheep and higher evenness in faeces from aborted sheep. Beta diversity showed richer and distinct vaginal microbiota in normal-delivery females compared to aborted ones. Firmicutes was the most abundant phylum observed.Dominant genera included: Moraxella (nasal); Mycoplasma, (blood); Streptococcus (milk); Ureaplasma (vaginal and preputial); Rikenellaceae RC9 gut group (faeces). Significant differences in bacterial composition, including infertility-linked vaginal pathogens, were found across female’s groups in all herds in the anatomical locations studied, revealing new species and tropisms. Moreover, taxonomic analysis identified C. burnetii in vaginal, milk and environmental samples. This first report of C. burnetii in the caprine nasal cavity suggests an underestimated tropism and may improve Q fever diagnosis. These findings underscore the need for herd-wide Q fever control measures, including males and normal-delivery females. Our findings contribute to new insights into the pathogen’s impact on small ruminant microbiota and a novel approach to studying infectious diseases in this sector.
Embargo
Natural killer (NK) cells play a critical role in the early innate immune response to Chlamydophila abortus infection in mice
(Elsevier, 2004-01) Río, L. del; Caro, M. R.; Gallego, M. C.; Sánchez, J.; Cuello, F.; Salinas, J.; Martínez Cáceres, Carlos Manuel; Navarro Cámara, José Antonio; Ortega Hernández, Nieves; Buendía Marín, Antonio Julián; Anatomía y Anatomía Patológica Comparadas
Chlamydophila abortus, the aetiological agent of ovine enzootic abortion, induces a strong inflammatory reaction that leads to the T helper cell (Th1) specific immune response necessary for the clearance of infection. Because the role of natural killer (NK) cells during the first stages of this response has received little attention, this study focused on determining the function of these cells in a mouse model of infection. The location of NK cells in the liver and spleen of infected mice was examined immunohistochemically with an anti-Ly49G monoclonal antibody. The number of NK cells increased during the infection both in spleen and liver. In subsequent experiments, an anti-asialo GM1 polyclonal antibody was injected to deplete the NK cells. NK-depleted mice showed a substantial increase in their susceptibility to C. abortus infection, with high mortality rates and an increased burden of bacteria in the liver. Histopathological studies showed that inflammatory foci, composed mainly of neutrophils, were greater in size and number in depleted mice, while numerous chlamydial inclusions were associated with the foci. Serum concentrations of IFN-gamma, a key cytokine in the control of C. abortus infection, were substantially reduced in the NK-depleted mice. To establish the relationship between NK cells and other components of the innate immune response, neutrophils were depleted with the RB6-8C5 antibody. These cells were shown to be crucial in the recruitment of NK cells to the inflammatory foci.
Open Access
Ontogenesis of the omasum: a comparative analysis of the Merino sheep and Iberian red deer
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Redondo, E.; Masot, Javier; García, Angela; Franco, A.
The aim of this study is to describe differences in the ontogenesis of the omasum in sheep (domestic ruminant) and deer (wild ruminant). A total of 50 embryos and fetuses of Merino sheep and 50 Iberian deer were used, from the first stages of prenatal life until birth. For the study, the animals were divided into five experimental groups according to the most relevant histological characteristics. The appearance of the omasum from the primitive gastric tube was earlier in sheep (22% gestation, 33 days) than in deer (25% gestation, 66 days). In both cases it displayed a primitive epithelium of a stratified, cylindrical, non-ciliary type. The appearance of four laminae of different sizes was always earlier in sheep than deer. At around 36% gestation in sheep (53 days) and 36% (97 days) in deer, the omasum consisted of 4 clearly-differentiated layers: mucosa (with epithelial layer and lamina propria), submucosa, tunica muscularis and serosa. The temporal order of appearance of the four order laminae and omasal papillae was always earlier in sheep than deer. The tegumentary mucosa of the omasum was without secretion capability in the first embryonic phases. From 67 days (26% gestation) the neutral mucopolysaccharides appeared in deer and at 46 days (30% gestation) in sheep. In both cases they continued to decrease until birth, this decrease being more pronounced in deer. Finally, the presence of neuroendocrine and glial cells was detected in deer at earlier stages than in sheep.
Open Access
Pharmacokinetic/pharmacodynamic modeling in plasma and milk and Mote Carlo simulations of marbofloxacin against Staphylococcu aureus and Mycoplasma agalactie in lactating sheep
(Elsevier, American Dairy Science Association, 2025-03-24) Serrano-Rodríguez, J. M.; Fernández-Varón, E.; Muñoz-Rascón, P.; Morón, R.; Díaz-Villamarín, X.; Fé Rodríguez, David Christian de la; Cárceles-García, C.; Cárceles Rodríguez, Carlos; Farmacología; Facultad de Veterinaria
In livestock ruminants such as sheep, different infectious diseases such as mastitis or contagious agalactia are originated from pathogens as Staphylococcus aureus and Mycoplasma agalactiae. Fluoroquinolones are authorized in dairy animals, including their extralabel use, as an alternative when other treatment failed in the European Union (EU), however, in the United States, are prohibited from extralabel drug use in food-producing animals. Marbofloxacin, a well-known fluoroquinolone is commonly used in dairy cattle in the EU at 10 mg/kg. However, their off-label use in sheep also has been described. Nevertheless, the dose extrapolations from dairy cows should include pharmacokinetic (PK) studies because of interspecies differences and the potential risks of antimicrobial resistance or toxicity. In this regard, the aims of this research were to (1) describe the i.v. and i.m. PK analysis of marbofloxacin in plasma and milk of lactating sheep at 10 mg/kg, (2) determine the MIC and calculate the tentative epidemiological cutoff values (TECOFF) for Mycoplasma agalactiae and Staphylococcus aureus wild-type isolates from sheep, and (3) conduct a pharmacokinetic and pharmacodynamic (PK/PD) analysis with the Monte Carlo simulation to obtain the probability of target attainment for different MIC values, known as the PK/PD cutoff values. The results of this study could help to establish the efficacy of a 10 mg/kg dosage regimen of marbofloxacin in lactating sheep. Plasma and milk concentrations were described with a nonlinear mixed effects model. The intramuscular biobioavailability was 88%, and the volume of distribution was 1.31 L/kg with a clearance value of 0.38 L/h/kg. Halflives after i.v. and i.m. dosing were 6.53 and 7.09 h in plasma, and 6.62 and 6.65 h in milk, respectively. High concentrations were determined in milk with area under the curve (AUC) milk/plasma ratios close to 1.28. The MIC values for Staphylococcus aureus and Mycoplasma agalactiae were obtained, and TECOFF values of 1.0 and 2.0 μg/mL, respectively, were determined. The Monte Carlo simulations predicted that the dosage regimen of 10 mg/kg per 24 h in lactating sheep can be adequate for intermediate and high MIC values of 0.5 and 1.0 μg/mL, respectively, and could be useful for populations with a target AUC/MIC ratio ≤48 for Staphylococcus aureus, but not for Mycoplasma agalactiae. Results derived for this study could be taken as previous tentative points for further studies of marbofloxacin in lactating and nonlactating sheep in a clinical context.
Open Access
Postnatal development of female sheep pineal gland under natural inhibitory photoperiods: an immunocytochemical and physiological (melatonin concentration) study
(Murcia : F. Hernández, 2003) Redondo, E.; Regodón, S.; Masot, A.J.; Gázquez, A.; Franco, A.
The purpose of this study was to determine structural and immunocytochemical changes taking place during the day and at night in developing sheep pineal gland under natural non-stimulatory photoperiods (summer solstice). Additionally, the diurnal cycle of plasma melatonin levels was charted and differences between diurnal and nocturnal pineal melatonin concentrations were analyzed. 36 ewes of three different ages were examined: infants (1-6 months old), pubertal and early fertile age (9-24 months old) and adults (36-60 months old). Plasma and pineal gland melatonin levels were higher in pubertal sheep than in infants or adults. Pubertal sheep pineal glands were also heavier, contained a larger number of pinealocytes and interstitial cells and displayed more evident innervation and vascularisation than infants or adults. There was no difference in the number of pinealocytes and interstitial cells between animals killed during daylight or at night. Gland weight, pinealocyte nuclear profile areas and plasma melatonin concentrations were all significantly higher at night than during the day.