Nicolas Nazar - Academia.edu (original) (raw)

Papers by Nicolas Nazar

Recibido: mayo de 2010 Aceptado: mayo 2011 1. Biólogo. Ciencia Avícola. ICTA Edificio de Investig... more Recibido: mayo de 2010 Aceptado: mayo 2011 1. Biólogo. Ciencia Avícola. ICTA Edificio de Investigaciones Biológicas y Tecnológicas. Facultad de Ciencias Exactas Físicas y Naturales. UNC. Avenida Velez Sarsfield 1611 (X5016GCA). Córdoba. Argentina. niconazar@yahoo.com.ar Efecto del estrés y del enriquecimiento ambiental temprano sobre parámetros de inmunidad celular de codornices japonesas juveniles

(A-E) letters indicate significant differences across time within... more (A-E) letters indicate significant differences across time within each CENV or SENV treatment (p<0.05); there were no significant differences between CENV/SENV treatments at the same age period.</p

*, r value significant at p < 0.01. The r values for every variable where obtained fr... more *, r value significant at p < 0.01. The r values for every variable where obtained from 20 birds.Spearman correlation analysis between CORT and molecular immuno-neuroendocrine mediators.</p

Results from the statistical analyses regarding heterophil/lymphocyte (H/L) ratio and th... more Results from the statistical analyses regarding heterophil/lymphocyte (H/L) ratio and the swelling response after the phytohemagglutinin-P (PHA-P) injection, expressed as percentage of inflammation.</p

The variables set to determine the existence of avian INPs in the present study are repr... more The variables set to determine the existence of avian INPs in the present study are represented around each bird. The size of the variable indicates if the animals show high or low response in each of the parameters in the INPs. LYMPH: lymphoproliferative response to PHA-P; Ab SRBC: antibody response against SRBC; FLD: frequency of leukocyte distribution; level of expression of mediators: IFN-γ and IL-1β (pro-inflammatory); and IL-4 and 13 (anti-inflammatory). "Fischer-like" quail with high CORT levels also manifest high FLD and IL-13, but low LYMPH, Ab SRBC, IFN-γ and IL-1β levels. "Lewis-like" counterparts have low CORT as well as low FLD and IL-13 responses, but high LYMPH, Ab SRBC, IFN-γ and IL-1β responses. These two extreme groups of birds do not differ in their IL-4 level.</p

Journal of Thermal Biology

Ethogram used for the data collection.</p

Mean (± SE) internal body temperature for acute CSTR and NSTR chicks; temperature was re... more Mean (± SE) internal body temperature for acute CSTR and NSTR chicks; temperature was registered in °C every 2h, at 0 (beginning of the cold stress), 2h, 4h, and 6h; (A-C) letters indicate differences over time within the CSTR or NSTR treatment; (a-b) letters indicate differences between CSTR and NSTR birds at the same time point.</p

Effect of the aggrupation dependent on the basal levels of CORT on the expression of two... more Effect of the aggrupation dependent on the basal levels of CORT on the expression of two pro-inflammatory (IFN-γ and IL-1β, panels A and B) and two anti-inflammatory mediators (IL-13 and 4, panels C and D). Data are adjusted means (number inside bars) ± SE. Number of birds per group = 10. Different letters indicate significant (p < 0.05) differences between groups. The relative expression of each target gene was calculated using the formula: Gene Level = 2-(Target Gene Ct – β-Actin Ct). The value obtained was then multiplied by 1x108 in order to fit the scale of the graphs.</p

Welfare assessment of fast and medium growth broiler strains and the effects of house location

El estudio del estres en aves de granja reviste gran interes ya que esta relacionado negativament... more El estudio del estres en aves de granja reviste gran interes ya que esta relacionado negativamente con su bienestar y habilidad para enfrentar cambios ambientales. En las ultimas decadas surge el uso del Ambiente Enriquecido (AE) para prevenir los efectos deletereos del estres. En este trabajo se evaluaron parametros de inmunidad celular en grupos mixtos de codornices criadas desde su eclosion en un AE, en aves expuestas a estres cronico y combinando ambas condiciones. El objetivo fue determinar si el AE presenta efectos inmunoactivadores en las aves y si estos efectos pueden compensar la inmunodepresion que induce el estres. Se alojaron codornices japonesas al azar en 12 habitaculos con temperatura y fotoperiodo controlados y acceso libre a agua y comida. Las aves fueron asignadas a uno de cuatro tratamientos que combino los efectos del enriquecimiento ambiental (con vs. sin enriquecimiento) y de la exposicion a un estres cronico (con vs. sin estres). Como estresor se empleo inmovi...

Transactions of The Royal Society of Tropical Medicine and Hygiene, 2021

Background West Nile virus (WNV) activity has been documented in the central region of Argentina ... more Background West Nile virus (WNV) activity has been documented in the central region of Argentina since 2005, but its maintenance network has not been elucidated yet. Methods We evaluated the susceptibility to WNV oral infection and transmission in a Culex pipiens quinquefasciatus mosquito population by means of a dose-dependent vector competence assay. Mosquitoes were orally infected with five different viral loads and evaluated for viral infection, dissemination and transmission. Results The evaluated population was susceptible to WNV oral infection. Disseminated infections were detected in all the viral doses but transmission was only detected in the higher doses (6 and 7 log10 plaque-forming units/ml). A linear relationship between doses and transmission rates could be established. Conclusions A minimum transmission threshold suggests that the Cu. p. quinquefasciatus from Argentina could acquire WNV infection from local urban birds and transmit the virus.

Scientific Reports, 2020

Environmental challenges are integrated in the inmunoneuroendocrine interplay, impacting the immu... more Environmental challenges are integrated in the inmunoneuroendocrine interplay, impacting the immune system of the challenged individuals, and potentially implying transgenerational effects on their offspring. This study addressed whether dietary supplementation with thymol can modulate the immune response of adult Japanese quail when simultaneously exposed to an inoculum of inactivated Salmonella Enteritidis and a chronic heat stress (CHS). We also evaluated whether the experienced situations by adults can affect the immune response of their undisturbed offspring. In the parental generation, supplemented quail exposed to CHS had a higher inflammatory response and similar values of the heterophil/lymphocyte (H/L) ratio than those that were not supplemented. In their offspring, those chicks whose parents were exposed to CHS showed higher inflammatory response and lower antibody production. Regarding the H/L ratio, chicks whose parents were supplemented showed lower H/L ratio values. D...

Poultry Science, 2018

The density-related permanence test (DRP) is used to classify young birds (while in groups) accor... more The density-related permanence test (DRP) is used to classify young birds (while in groups) according to their individual permanence in proximity to either a high or low density of conspecifics (HD or LD, respectively). The birds' performance in DRP was associated with underlying differences in the social responses of their individuals. Quails in homogeneous groups of LD residents responded with less compact groups and higher levels of agonistic interactions to the presence of an intruder, and showed higher levels of agonistic interactions among cagemates than the homogeneous groups of HD birds. This study deepen the characterization of DRP evaluating whether contrasting behavior during test is associated with birds' stress responses to challenging situations during rearing. Plasma corticosterone responses were individually assessed after submitting DRP categorized birds to a brief (10 min) partial restraint (mechanical stressor; experiment 1), or after introducing them during 5 min as intruders in homogeneous groups of 6 unknown same category (HD or LD) conspecifics (social stressor; experiment 2). Experiment 1 showed that basal corticosterone levels were similar in all groups and the partial mechanical restraint induced an increase in plasma corticosterone concentration also in all groups. However, the increase induced by the stressor was higher in the LD birds than in their HD counterparts. In experiment 2, compared to controls, social stressor showed no plasma corticosterone changes in the intruders that were introduced in an unfamiliar group of HD conspecifics. However, intruders (both HD and LD) that were visiting the LD residents showed an increased corticosterone response compared to their control counterparts. Results suggest that categorization of birds in the DRP test could have relevance for selection programs oriented to obtain birds better suited to intensive rearing conditions that includes high density of animals and exposure to unavoidable stressors.

Animal, 2018

Chronic heat stress (CHS) exposure negatively impairs avian’ immunoneuroendocrine interplay. Thym... more Chronic heat stress (CHS) exposure negatively impairs avian’ immunoneuroendocrine interplay. Thymol has shown several bioactive properties including antioxidant, bactericidal, antifungal and gamma-aminobutyric acid modulator activities. Indeed, supplementation with thymol has been used with positive effects on poultry production and immune-related variables. This study evaluates whether a thymol dietary supplementation can be used as a new functional feed strategy to mitigate CHS deleterious effects on endocrine, biochemical and immune-related variables. Starting at 100 days of age, 24 fully adult Japanese quail were fed with a diet supplemented with thymol (≈80 mg/quail per day) and other 24 quail remained non-supplemented (control diet). Between 119 and 127 days of age, half of the quail within those groups were submitted to a CHS by increasing environmental temperature from 24°C to 34°C during the light phase and the other half remained at 24°C (non-stressed controls). A period o...

Mucosal Immunology, 2018

Biological rhythms are periodic oscillations that occur in the physiology of the organism and the... more Biological rhythms are periodic oscillations that occur in the physiology of the organism and the cells. The rhythms of the immune system are strictly regulated and the circadian alteration seems to have serious consequences. Even so, it is not clear how the immune cells of the intestinal mucosa synchronize with the external environment. Besides, little is known about the way in which biological rhythms affect the critical functions of intestinal immunity, such as oral tolerance. We studied fluctuations in the relevant parameters of intestinal immunity at four different times throughout the day. By using multivariate statistical tools, we found that these oscillations represent at least three different time frames with different conditions for tolerance induction that are altered in Per2ko mice lacking one of the clock genes. Our results allowed us to characterize a window in the final stage of the dark phase that promotes the induction of specific regulatory populations and favors its location in the lamina propria. We show here that, at the end of the intake, the entry of luminal antigens, soluble factors, and leukocyte populations converge in the mesenteric lymph nodes (MLN) and display the greatest potential of the tolerogenic machinery.

The Journal of Nutritional Biochemistry, 2018

Soy genistein administered in soluble chitosan microcapsules maintains antioxidant activity and l... more Soy genistein administered in soluble chitosan microcapsules maintains antioxidant activity and limits intestinal inflammation. Jnb (2018),

Stress (Amsterdam, Netherlands), May 25, 2018

Avian require comfortable temperatures for optimal development and heat stress is a high concern ... more Avian require comfortable temperatures for optimal development and heat stress is a high concern in warm weather countries. We aimed to assess the dynamics of immunoendocrine and biochemical variables responses of birds exposed to a heat stressor applied during daylight hours, during the chronic stress and the recovery periods. We hypothesize that variables involved in the birds response will be differentially and gradually modified during those periods. Female quail (n = 210) were housed in six rearing boxes. At 29 days of age, the temperature in three boxes was increased from 24 to 34 °C during the light period throughout the nine days (Stress Treatment). The other three boxes remained at 24 °C and were used as controls. The subsequent 12 days were considered as recovery period. Different sets of 12 birds/treatment were blood-sampled at 29 (basal), 32, 35, 38 (stress), 41, 44, 47, and 50 (recovery) days of age, respectively. Immunoendocrine (corticosterone, lymphoproliferation, he...

Scientific Reports, 2017

Immune-neuroendocrine phenotypes (INPs) stand for population subgroups differing in immuneneuroen... more Immune-neuroendocrine phenotypes (INPs) stand for population subgroups differing in immuneneuroendocrine interactions. While mammalian INPs have been characterized thoroughly in rats and humans, avian INPs were only recently described in Coturnix coturnix (quail). To assess the scope of this biological phenomenon, herein we characterized INPs in Gallus gallus (a domestic hen strain submitted to a very long history of strong selective breeding pressure) and evaluated whether a social chronic stress challenge modulates the individuals' interplay affecting the INP subsets and distribution. Evaluating plasmatic basal corticosterone, interferon-γ and interleukin-4 concentrations, innate/acquired leukocyte ratio, PHA-P skin-swelling and induced antibody responses, two opposite INP profiles were found: LEWIS-like (15% of the population) and FISCHER-like (16%) hens. After chronic stress, an increment of about 12% in each polarized INP frequency was found at expenses of a reduction in the number of birds with intermediate responses. Results show that polarized INPs are also a phenomenon occurring in hens. The observed inter-individual variation suggest that, even after a considerable selection process, the population is still well prepared to deal with a variety of immuneneuroendocrine challenges. Stress promoted disruptive effects, leading to a more balanced INPs distribution, which represents a new substrate for challenging situations.