Guilherme Oberlender

Effect of Ractopamine on Lipid Metabolism in vivo - a Systematic Review

The aim of this article was to evaluate the in vivo mechanism of action through which ractopamine reduces the amount of adipose tissue in carcass of animals fed diets supplemented with this drug. Literature search was carried out, using the keywords Ractopamine, lipogenesis, lipolysis, fatty acid and adipose tissue. The scoring system was designed for the adequacy of the methodology. A total of eight papers were found - all published in the English language. The determination of lipolysis and lipogenesis was carried out using different methods - from the quantification of non-esterified fatty acids in the blood to molecular analyses of adipose tissue. The review analysis suggested that, at least in the pigs, the use of this drug reduced lipid deposition in the carcass due to a greater inhibition of lipogenesis than an increase in lipolysis.

Role of insulin-like growth factor-I and follicular fluid from ovarian follicles with different diameters on porcine oocyte maturation and fertilization in vitro

The objective of this study was to determine the effects of insulin-like growth factor-I (IGF-I) (0, 60, 120, 180, and 240 ng/mL) and follicular fluid (FF) derived from 2 to 5 and 6 to 10 mm diameter follicles (SpFFs and LpFFs, respectively) added during in vitro maturation (IVM) of porcine oocytes on nuclear maturation and IVF. Cumulus-oocyte complexes (COCs) were matured in NCSU-37 medium supplemented with SpFFs or LpFFs and various IGF-I concentrations. The COCs were cultured for 44 hours, and then fertilized in vitro. Maturation and IVF results were recorded 18 hours after insemination. The IVM (%) was higher (P < 0.05) in the COCs matured in LpFFs than with SpFFs when 0 (90.0 ± 6.9 vs. 76.3 ± 10.7) or 60 ng/mL IGF-I (92.0 ± 8.1 vs. 81.8 ± 10.2) was added. In SpFFs media, there was a quadratic relationship (P < 0.01) between IGF-I concentration and IVM (peak results at IGF-I = 129 ng/mL). However, when the COCs were matured with LpFFs, there was a decreasing linear effect between IGF-I concentration and IVM. At all concentrations of IGF-I, the percentage of degenerated oocytes was higher in COCs matured in SpFFs than in LpFFs. Penetration (%) did not differ (P > 0.05) between COCs matured with SpFFs or LpFFs when 60 (66.8 ± 9.4 vs. 72.7 ± 11.3) or 180 ng/mL of IGF-I (75.7 ± 10.4 vs. 73.8 ± 13.2) were used. Monospermy (%) was similar between SpFFs and LpFFs only with addition of 120 ng/mL IGF-I. The IVF performance (%) did not differ between COCs matured with SpFFs or LpFFs when IGF-I concentrations of 120 (28.5 ± 8.8 vs. 38.5 ± 8.3) and 180 ng/mL (24.3 ± 10.2 vs. 30.12 ± 8.2) were used. There was no effect of IGF-I concentration or of FF type on the number of penetrated sperm per oocyte and on male pronuclear formation. For COCs matured with SpFFs, there was a quadratic relationship between IGF-I concentration and penetration, monospermy, and IVF performance (peak results at IGF-I = 179, 122, and 135 ng/mL, respectively). Thus, on the basis of the observed quadratic relationships, we inferred that when using SpFFs, the addition of IGF-I (122-179 ng/mL) to the IVM medium produced results similar to those obtained with LpFFs without adding IGF-I. In conclusion, the addition of IGF-I to the IVM medium supplemented with SpFFs increased maturation and improved IVF results. Alternatively, IGF-I had no effect on IVM or IVF when used with LpFFs.

Comparison of two different methods for evaluating boar semen morphology

El objetivo de este estudio fue comparar el uso y la eficacia de dos tecnicas para evaluacion de la morfologia espermatica del semen porcino. La preparacion humeda con una solucion de formaldehido-citrato 2,94% y otra con el uso del colorante Rosa de Bengala. Se evaluaron 58 eyaculados de ocho verracos de alto desempeno, con edad entre 20 y 25 meses. Despues de la recogida del semen, la morfologia espermatica fue evaluada por dos tecnicas: la preparacion humeda convencional (solucion de formaldehido-citrato 2,94%) observada en microscopio de contraste de fase (1.000X de magnificacion) y la tecnica que utiliza un frotis preparado a partir del colorante Rosa de Bengala, analizado bajo un microscopio optico (400X de magnificacion). Se observo que el porcentaje de cambios de la cabeza, acrosoma, pieza intermedia y el total de cambios morfologicos no fueron diferentes (P > 0,05) entre los dos metodos. Se obtuvo un mayor numero de defectos de la cola (P < 0,05) con el uso de la tecnica de tincion con el colorante Rosa de Bengala en comparacion con la tecnica convencional. Esto se explica por el manejo en la preparacion del frotis que puede conducir a una mayor probabilidad de romper la cola, lo que conduce a la visualizacion de la anomalia cola rota. Se puede concluir que el uso del colorante Rosa de Bengala es un metodo eficaz para la evaluacion de la morfologia del semen porcino, senalando que importantes cuidados deben ser tomados, especialmente en la preparacion del frotis para que no ocurran cambios en los resultados, principalmente en los cambios de la cola.

Comparison of the proximal tibial angles between Labrador Retrievers and other dog breeds with and without cranial cruciate ligament rupture

The influence of the proximal tibia conformation in the rupture of the cranial cruciate ligament (CCL) in dogs is still controversial, especially in Labrador Retrievers. The aim of this study was to compare the angles of the proximal tibia between Labrador Retrievers and other large breeds of dogs, both groups with and without CCL rupture. Radiographic images of 64 stifle joints were obtained and divided into four groups of 16 images. Group 1 consisted of Labrador dogs without orthopedic disorders, group 2 consisted of Labrador dogs with CCL rupture, group 3 consisted of dogs of various large breeds without orthopedic disorders, and group 4 consisted of dogs of various large breeds with CCL rupture. The radiographs were performed in mediolateral projection with the stifle joint positioned at an approximate angle of 135°. The tibial plateau angle showed an overall average of 22.17°±4.20°, and there was no statistically significant difference between the groups. The patellar ligament angle in relation to the tibial plateau had a mean of 103°±4.20°, and there was a significant difference between groups 1 and 4. The patellar ligament angle in relation to the common tangent at the tibiofemoral contact point showed an average of 99.06°±6.08°, and there was no difference between the groups. The patellar ligament insertion angle had an overall average of 51.45°±5.06°, and there was a significant difference between the two groups of normal dogs and two groups of ruptured dogs. In conclusion, the tibial plateau angle, the patellar ligament angles and the patellar ligament insertion angle do not seem to be predisposing factors for rupture of the CCL in Labrador Retriever dogs. In general, there seems to be no relationship between the angles of the proximal tibia and the CCL rupture in dogs.

Avaliação morfológica e morfométrica de ovários, tubas uterinas e útero de fêmeas suínas pré-púberes em diferentes fases do ciclo estral

Studies are performed in developing techniques/procedures that provide greater reproductive performance in farm animals, including pigs. In this sense, the study of gilts reproductive organs at different oestrus cycle stages for assessing the presence of abnormalities and/or other parameters that may affect the future animal fertility is important. In order to evaluate the morphological, morphometric and histomorphometric features of ovaries, uterus and uterine tubes (UTs) characteristics of prepubertal gilts at different oestrus cycle stages, reproductive tracts from 48 animals immediately after slaughter were obtained. After, the structures were dissected and removed, and the ovaries were used for classification of oestrus cycle stage of each gilt in follicular phase (FP) and luteal phase (FL). Then, morphometric evaluations of ovaries, UTs, uterine horns and uterine body were performed. Besides that, medial segments of UTs and uterus were fixed in Bouin solution, processed and included in paraffin, when histological sections of 5.0 micrometers (µm) were obtained and stained with Hematoxylin and Eosin. Histomorphometric analyzes using image capture system and specific software were performed. Afterwards, data were submitted to Students t test for assessment the statistical differences (P 0.05) between morphometric parameters of ovaries, UTs and uterus of gilts in FP and LP. Likewise, in respect to the placement of reproductive structures, both in the oestrus cycle stages, as in the general average, there was no difference (P>0.05). Regarding the histomorphometric variables, gilts classified in FP presented a higher (P<0.05) height of glandular and UT epithelium compared to animals in LP. On the other hand, the diameter of endometrial glands was higher (P<0.05) in gilts at LP compared to FP. Furthermore, gilts in LP presented a higher (P<0.05) proportion of endometrium occupied by glands, whereas animals in FP had a higher (P<0.05) proportion of connective tissue and blood vessels. In conclusion, in prepubertal gilts, the histomorphometric parameters as endometrial glands diameter, the height of glandular epithelium and of UT epithelium and the proportion of endometrium occupied by connective tissue, besides the glands and blood vessels varies through the oestrus cycle, possibly under the influence of ovarian steroids.

Porcine follicular fluid concentration of free insulin-like growth factor-I collected from different diameter ovarian follicles

The study aimed to quantify the concentrations of free IGF-I in serum and fluid of ovarian follicles in pre-pubertal gilts and describe the ovarian morphology by measuring the size of the ovaries and counting the number of surface follicles. Ovaries (n=1,000) from pre-pubertal gilts were obtained immediately after slaughter. A total of 10 samplings were performed, with ovaries obtained from 50 females for each collection. The follicles situated on the surface of each ovary were classified as small (SFs, 2 to 5mm in diameter) or large (LFs 6 to 10mm in diameter) and the follicular fluid was obtained by follicle aspiration. The collection of serum samples was performed after the gilts exsanguination using sterile tubes. From the pool of serum and follicular fluid obtained from 50 females, the concentration of free IGF-I was determined in each sample using an enzyme immunoassay kit (ELISA). The description of ovarian morphometry was performed in 100 ovaries from randomly selected gilts. The larger and smaller lengths of ovaries were measured, and the total number of SFs and LFs present on the surface of each ovary were also counted. The IGF-I concentration was greater (P<0.05) in LFs (170.92±88.29 ng/mL) compared with SFs (67.39±49.90ng/mL) and serum (73.48±34.63ng/mL). The largest and smallest length of the ovaries was 26.0±3.0 and 19.0mm ±2.0mm, respectively. The number of SFs (70.86±25.76) was greater (P<0.01) than LFs (6.54±5.26). The study concluded that LFs present greater levels of IGF-I when compared with SFs and blood, which is related to increased activity of the LFs and its differentiation to ovulation. In addition, ovaries of pre-pubertal gilts have a higher number of SFs compared to LFs. Therefore, our study demonstrated unique data regarding the physiological concentration of free IGF-I in ovarian follicles, that can be used in future research to evaluate the addition of this hormone in the in vitro production media of porcine embryos with the goal to improve the technique efficiency.

Feline hypertrophic cardiomyopathy: an echocardiographic approach

RESUMEN La cardiomiopatia hipertrofica felina es una enfermedad primaria del miocardio que se caracteriza por una leve a severa hipertrofia concentrica primaria del miocardio ventricular. Los factores hereditarios y mutaciones causales se han atribuido al desarrollo de la enfermedad en algunas razas, como los gatos Maine Coon y Ragdoll. Sin embargo, esta enfermedad sigue siendo un reto para los veterinarios debido a la dificultad del diagnostico precoz y el riesgo de muerte subita de los animales afectados. La ecocardiografia es una herramienta no invasiva de eleccion para el diagnostico de las enfermedades cardiacas en los gatos. Nuevas tecnicas ecocardiograficas como el Doppler Tesidual (el color bidimensional, el modo M a color y el modo de onda pulsada), Strain y Strain rate , han demostrado ser eficaces en el diagnostico temprano de la disfuncion del miocardio, incluso en ausencia de hipertrofia en el examen ecocardiografico convencional. Esta revision pretende acercar la informacion mas reciente sobre el diagnostico ecocardiografico de la cardiomiopatia hipertrofica felina.

Estudo comparativo de diferentes técnicas de avaliação da concentração espermática em suínos

A determinacao precisa e acurada da concentracao espermatica do ejaculado suino e importante na producao de doses inseminantes com um numero determinado de espermatozoides. O objetivo do trabalho foi comparar a eficiencia de algumas tecnicas de mensuracao da concentracao espermatica no semen e determinar equacoes de predicao, estabelecendo uma correlacao entre elas. Foram coletados 93 ejaculados que tiveram as concentracoes espermaticas determinadas de forma direta (câmara de Neubauer, CN) ou indireta (espermiodensimetro, ED e espectrofotometro, EF). Foi utilizado um delineamento em blocos casualizados, com 93 repeticoes e duas analises por parcela experimental. Os valores foram submetidos a analise de variância, as medias submetidas ao teste SNK e os tratamentos interrelacionados pelo ajuste do modelo linear entre os dados (equacoes de predicao). Nao houve diferenca na determinacao da concentracao espermatica obtida com ED (361,7 x 106 sptz/ml) e EF (343,7 x 106 sptz/ml), porem estes valores foram maiores com relacao a CN (245,3 x 106 sptz/ml). As equacoes obtidas foram: ED= -0,30 [volume (em ml)] + 0,61 EF + 213,47 (R2= 0,72) e ED= -0,50 [volume (ml)] + 0,47 CN (R2= 0,7). As tecnicas de mensuracao da concentracao espermatica pelo ED e EF superestimam os valores em relacao a CN. Novos estudos devem ser conduzidos para determinar a verdadeira eficiencia com que essas tecnicas sao empregadas a campo.

In vitro fertilization of porcine oocytes is affected by spermatic coincubation time

The aim was to study the effects of different gamete coincubation times on porcine in vitro fertilization (IVF), and to verify whether efficiency could be improved by reducing oocyte exposure time to spermatozoa during IVF. In groups of 50, a total of 508 immature cumulus-oocyte complexes (COCs) were matured in NCSU-37 medium. The COCs were cultured for 44 hours and then inseminated with in natura semen (2,000 spermatozoa/oocyte). The sperm and oocytes were coincubated according to the following treatments (T): T1 = oocytes exposed to spermatozoa for one hour (173 oocytes), T2 = oocytes exposed to spermatozoa for two hours (170 oocytes), and T3 = oocytes exposed to spermatozoa for three hours (165 oocytes). After these coincubation periods, the oocytes were washed in fertilization medium (TALP medium) to remove spermatozoa not bound to the zona pellucida and cultured in another similar medium (containing no sperm). Eighteen to twenty hours after fertilization, the putative zygotes were stained in Hoechst-33342 to evaluate the IVF results. The penetration rate was higher (P 0.05) between oocytes exposed to spermatozoa for one (T1) and three hours (T3). However, optimum (P=0.048) results were obtained after two hours of coincubation, when the rate of fertilization performance was 50.16±8.52%. The number of penetrated sperm per oocyte, as well as male pronucleus formation, did not differ (P>0.05) between the treatments evaluated. Under these assay conditions, especially in relation to the sperm concentration used, gamete coincubation for a period of two hours appears to be optimal for monospermy and fertilization performance. Thus, it is the optimal time period for obtaining a large number of pig embryos capable of normal development.

Avaliação da depressão miocárdica por meio do feature tracking bidimensional em cadelas com sepse

The aim of this prospective study was to analyze the left ventricular function of dogs who had sepsis or not and diagnose myocardial depression early on through the two-dimensional feature tracking imaging (2D-FTI). Twenty-nine dogs diagnosed with pyometra, a pathology used as an experimental model for sepsis were evaluated. The animals were subjected to conventional echocardiography and 2D-FTI, and divided into three groups: Group I (control), group II (sepsis pyometra) and group III (no sepsis pyometra). Regarding the parameters of conventional echocardiography, there was no statistical difference between the groups. As for the radial Strain, group II and III had lower ventricular function at diagnosis (22.805.80 Group I; 18.455.96 Group II; 18.719.45 Group III; P = 0.032) and group III maintained this reduction in return. Regarding the radial Strain rate, only the III group had lower ventricular function at diagnosis (1.900.57 Group I; 1.910.70 Group II, 1.570.53 Group III; P = 0.021). For the Longitudinal Strain we observed lower ventricular function in groups II and III at diagnosis (11.043.38 Group I, Group II 8.593.97, 8.211.99; P = 0.048) and ten days after surgery (11.043.38 Group I; 9.002.16 Group II; 8.122.27 Group III; P = 0.048). The 2D-FTI was able to detect early changes in left ventricular function, suggesting myocardial depression frame, even in female dogs with pyometra without clear clinical picture of sepsis, which were not seen in conventional echocardiography. Thus, this model can be useful in diagnosis, because it can detect early cardiac changes, enabling a rapid therapeutic intervention.