Ricardo Chihuailaf

Oleic acid induces intracellular calcium mobilization, MAPK phosphorylation, superoxide production and granule release in bovine neutrophils

Oleic acid (OA) is a nonesterified fatty acid that is released into the blood during lipomobilization at the time of calving in cows, a period where increased risk of infection and acute inflammation is observed. These data suggest potential OA-mediated regulation of innate immune responses. In the present study, we assessed the effects of OA on intracellular calcium release, ERK1/2 phosphorylation, superoxide production, CD11b expression and matrix metalloproteinase-9 (MMP-9) release in bovine neutrophils. Furthermore, the presence of GPR40, an OA receptor, was assessed by RT-PCR, immunoblotting and confocal microscopy. OA induced, in a dose-dependent manner, intracellular calcium mobilization, superoxide production and CD11b expression in bovine neutrophils; these effects were reduced by the intracellular chelating agent BAPTA-AM. OA also induced ERK2 phosphorylation and MMP-9 release. RT-PCR analysis detected mRNA expression of a bovine ortholog of the GPR40 receptor. Using a polyclonal antibody against human GPR40, we detected a protein of 31kDa by immunoblotting that was localized predominately in the plasma membrane. The selective agonist of GPR40, GW9508, induced intracellular calcium mobilization and ERK2 phosphorylation. In conclusion, OA can modulate bovine neutrophil responses in an intracellular calcium-dependent manner; furthermore, these responses could be induced by GPR40 activation.

Intervalos de referencia en parámetros sanguíneos indicadores del balance mineral para grupos de vacas lecheras en el sur de Chile

The aim of this study was to propose reference intervals (RI) for blood markers of mineral balance in prepartum and lactating groups of dairy cows in the Sou...

Blood mineral concentrations in the endangered huemul deer (Hippocamelus bisulcus) from Chilean Patagonia.

Abstract Concentrations of calcium, magnesium, copper, zinc, and selenium were measured in plasma from 11 huemul (Hippocamelus bisulcus) from Chilean Patagonia. Except for zinc and copper, concentrations of these minerals were similar to those of other deer species.

Rumenocentesis dorsomedial: un procedimiento seguro para la obtención de líquido ruminal en vacas lecheras a pastoreo

Two experiments were carried out to 1) compare pH values of rumen fluid samples (RF) obtained from dairy cows by dorsomedial rumenocentesis, a probe and perm...

Estudio retrospectivo de la prevalencia de desbalances minerales en grupos de vacas lecheras en el sur de Chile: a retrospective study

The aim of this study was to describe and compare the frequency of mineral imbalances in groups of prepartum and lactating dairy cows in the south of Chile. ...

Plasma retinol concentration in grazing heifers: First data obtained from a dairy herd in the south of Chile

Vitamins are organic molecules with a complex structure, which are essential in very small quantities for the health, growth and reproduction of ruminants. The generic term vitamin A is used when referring to retinoids that exhibit the biological activity of retinol (IUNS 1990)and includes both natural forms and synthetic analogues. Vitarnin A is physically a pale yellow crystalline solid substance, which is water insoluble. Chemically, it is a hydrophobic â-ionone ring with a conjugated isoprenoid lateral chain containing a polar group at its end (Debier and Larondelle 2005). The ability to synthesizecompoundswith vitamin A activity is limited to microorganisms and plants (Harrison 2005). Thus, animals must obtain vitamin A from the diet, where it can be found as a preformed vitamin in animal foods or as a provitarnin in plant foods. Provitamins are members of the carotenoid family, and the term is used as a generic description of all the compounds that exhibit qualitatively the biological activity of â-carotene (IUNS 1990). Â-carotene is one of the most widely available carotenoids and the main precursor of vitamin A (During and Harrison 2004). It is known that in animals, vitamin A intervenes in a variety of biological mechanisms associated to the maintenance of epithelial cells, gene regulation, immune cell function, reproduction and vision (Chew 1987, Debier and Larondelle 2005). Due to the above mentioned, the most frequent signs of deficiency are: impaired dark adaptation, xerophthalmia with the cornea becoming thick and hazy, decreased cellular and humoral immunity. In male animals it can cause degenerative damage of epithelial cells in seminiferous tubules while in the female it leads to abortion, delivering stillborn or weak foetuses and placental retention (Radostits et al 2002). According to Herdt and Stowe (1991) the evaluation of vitamin A metabolic balance is not a routine practice in animals but it should be considered as part of the general health diagnosis of the herd, especially if there is evidence of a decrease in reproductive efficiency and immunosuppression of unknown origino Hammell et al (2000) have mentioned that the hepatic concentration of vitamin A is the most reliable indicator used to evaluate the metabolic balance of vitamin A in animals. However, even though the determination of plasma concentration of retinol is a less sensitive indicator, it is the most practical and useful method to evaluate the status of vitamin A in the herd (Herdt and Stowe 1991), with plasma concentrations between 25 and 60 µg/dL indicating an acceptable level ofthe vitamin adult cattle (Frye et al 1991). Plasma concentration of vitamin A is usually expressed as the addition of retinol and retinyl palmitate concentrations; however, retinol gives more clinical information and can be measured through chromatographic techniques (Herdt and Stowe 1991). High Performance Liquid Chromatography (HPLC) is used to separate molecules with a high analytical sensitivity (Paulo et al 1999), making it a useful tool to determine vitamin concentration in bovines. Retinol requirements have been the subject of many studies. According to ARC (1980) the daily requirements of retinol are 20 µg/kg of body weight for maintenance and growth, 30 µg/kg of body weight during breeding and pregnancy and 25 to 65 µg/kg of body weight for lactating cows. NRC (2001) mentions that vitamin A, expressed as retinol equivalents, should be supplemented in amounts of 24 µg/kg of body weight during growth and 33 µg/kg of body weight during lactation, pointing out that these values do not represent the total requirement of the vitamin and consider animals being fed conserved forage. In the south of Chile, the management system for dairy cows is based on grazing pasture and the supplementation with concentrate and conserved forage is used in critical periods (Pulido et al 1999). Considering that green fresh forage is the main source of vitamin A precursors, it is possible to estimate that the contribution should be adequate for grazing cattle; however, the quality and quantity of the forage provided by the pasture changes throughout the year, under which circumstances the nutrient contribution could vary. Furthermore, most grains are void of carotenoids and the stored forages have lower concentrations of them (NRC 2001). In Chile there are no records about vitamin A status in dairy neither beef cattle; it could limit the nutritional management and the efficiency of the herd. The aim of this study was to measure the plasma retinol concentration in grazing heifers using a standardized analytic methodology and to record its variation during winter and spring in a herd in southern Chile.

Interpretation of plasma selenium data in huemul: response to Flueck et al.

Flueck et al. (2014) expressed several misconceptions about the huemul plasma micronutrient data we provided (Chihuailaf et al. 2014). We expressed selenium (Se) plasma values as mean, median, ranges, and intervals for comparison with those reported for other deer species, which were mostly raw values. We did not refer to the Se values as a ‘‘reference interval’’ but as an ‘‘interval calculated.’’ Perhaps we should have used a different term to avoid confusion. Our data do not meet the requirements of a reference interval according to the American Society of Veterinary Clinical Pathology (Friedrichs et al. 2012). Similarly, Se values reported by McDowell et al. (1995) did not receive the statistical treatment required to be considered a reference interval; they provided only a data range expressed as maximum and minimum values found by the authors for one species in one area. There is no single definition for ‘‘healthy population’’ for either wild or domestic animals. Therefore, building reference intervals requires safeguards for selection of sampling animals (Friedrichs et al. 2012). Also, appropriate statistical analysis of the data is required. The American Society of Veterinary Clinical Pathology suggests removal of outlier values to minimize error when establishing reference intervals, so a large sample of healthy animals is needed (Friedrichs et al. 2012). These conditions are more easily met in domestic livestock than in wild animals. It is also important to identify values that may indicate a deficient, marginal, or sufficient status for a given micronutrient, implying that we know the requirement criteria (Suttle 2010). This issue has been discussed for domestic livestock where each production system, geographic area, and breed, among several other factors, requires a separate reference value for each micronutrient; but it also is a growing necessity for wildlife and their ecosystems. For example, Se requirements for livestock in the US are higher than those reported for New Zealand (Suttle 2010). This implies that a trace mineral reference interval developed for one species in one geographic area or ecosystem is likely insufficient to categorize other species in other habitats. Furthermore, if we attempt to equate requirements of wild species with those for production livestock, which are subject to additional metabolic pressure to maintain productive efficiency, we would introduce an error in biologic data interpretation. If huemul deer (Hippocamelus bisulcus) inhabited North America, where acid rain produces soils low in Se, Flueck et al. (2014) might be correct in their comments, but southern South America lacks chronic atmospheric pollution (Huygens et al. 2008). It is important to consider that the data provided by Chihuailaf et al. (2014) only suggest a condition that should be further investigated. After all, huemul have survived since the Pleistocene (Marin et al. 2013) in habitats dominated by volcanic soils lacking in Se (reviewed by Chihuailaf et al. 2014).

Efecto de la suplementación preparto con selenio levadura oral o selenato de bario parenteral en las concentraciones sanguíneas de selenio en vacas lecheras y sus crías

Con el objetivo de evaluar el efecto de la suplementacion con dos fuentes de selenio en las concentraciones de selenio en calostro y sangre de vacas y de sus crias se suplemento un mes previo a la fecha estimada de parto a un grupo de 13 vacas (Se-levadura) con una fuente organica de selenio (3 mg/ vaca/dia p.o), a otro grupo de 15 vacas (Se-bario) con selenato de bario (1 mg Se/kg peso via SC, dosis unica), y a otro grupo de 15 vacas permanecio sin suplemento (Control). No se encontraron diferencias en las concentraciones sanguineas de Se en las madres y en las crias al momento del parto (P > 0,05) y tampoco en las concentraciones de Se en calostro (P > 0,05). Ademas se observo un incremento (P < 0,05) de la actividad sanguinea de la enzima glutation peroxidasa en las vacas suplementadas con levadura selenizada (307 ± 21 U/g Hb) y con selenato bario (320 ±25 U/g Hb) respecto de las controles (221 ±14 U/g Hb), situacion similar fue observada en las crias nacidas de estas vacas. Se concluye que la suplementacion con Se-levadura o con Se-bario, en la forma empleada en este experimento, no modifican las concentraciones de selenio en sangre de las madres y sus crias asi como en el calostro

Pesquisa de lasalocida y monensina en leche cruda de vacas lecheras suplementadas con estos ionóforos

SUMMARY The ionophores lasalocid and monensin have been used as food additives to improve body weight gain in beef cattle and milk production in dairy cows. The aims of this work were to detect the presence of these compounds in raw milk samples and their ruminal disappearance rate in dairy cows using HPLC techniques. Two Friesian herds were used. Cows from one herd were supplemented with lasalocid and the other with monensin during 18 and 21 days respectively, and according to the recommended dose (300 mg/d). Daily raw milk samples were obtained during the supplementing period and the presence of lasalocid and monensin was analysed using HPLC techniques (LOD 30 and 5 ppb respectively). In a parallel trial fluid ruminal samples obtained from fistulised cows up to 24 hours after a single intra ruminal administration with the ionophores were analysed using the same HPLC techniques. Both ionophores were not detected in any of the milk samples during all the experimental period. The low transference of these ionophores to the milk could be related to their expected low absorption rate related to their physical-chemical proprieties. Lasalocid was detected in the ruminal fluid up to 6 hours after administration and monensin up to 4 hours of administration. According to the results, lasalocid and monensin are not detected in raw milk samples from supplemented cows using techniques with detection limits of 30 and 5 ppb, respectively.

Concentración de selenio en leche de estanques de rebaños lecheros del sur de Chile y su relación con indicadores productivos

An observational study was conducted in 59 Chilean dairy farms to evaluate bulk tank milk selenium (Se) concentration, and its association with measures of m...