Límites nutricionales para dietas de cabras lecheras en crecimiento

El objetivo del presente trabajo fue revisar el consumo de materia seca y las necesidades nutritivas de cabras lecheras de reposición estabuladas para establecer límites nutricionales aplicables a la formulación de dietas por programación lineal a mínimo coste. El diseño de dietas nutricionalmente adecuadas y económicas requiere que el nutricionista estime correctamente el consumo de materia seca y forraje y los aportes y las necesidades de nutrientes. La bibliografía revisada sugiere que el consumo total de materia seca de las cabras oscila entre los límites físico y fisiológico impuestos por la capacidad del tracto digestivo y las necesidades energéticas diarias. El efecto de llenado digestivo puede relacionarse con los carbohidratos estructurales de la dieta, mientras la saciedad metabólica se relaciona con la concentración energética de la dieta. El consumo mínimo de forraje necesario para mantener la salud ruminal es bajo, mientras que el consumo máximo de forraje está determinado probablemente por el contenido de fibra neutrodetergente de la dieta. Los aportes y las necesidades de energía y proteína calculadas según los dos sistemas de valoración más modernos son similares, por lo que es indistinto usar cualquiera de ambos para optimizar dietas. Las propuestas recientes para el cálculo de los aportes y las necesidades de calcio y fósforo ofrecen una mayor precisión

Diet digestibility and production performance in dairy goats consuming plant oils

The aim of this study was to investigate the effects of differently unsaturated vegetable oils added to dairy goat diets on apparent digestibility and performance traits. Twelve Malagueña goats were randomly assigned to one of four treatments: no oil (CONTROL), 48 g/d of high oleic sunflower oil (GAO), regular sunflower oil (RSFO) or linseed oil (LIN). The basal diet was made of alfalfa hay and a pelleted concentrate, which included the respective oil and chromium as indicator. The experimental period lasted 21 days. The digestibility of dietary components, except for fat, did not differ between treatments (P > 0.05). Oil inclusion in the diet significantly (P < 0.05) increased fat digestibility. There were no significant differences (P > 0.05) in dry matter intake, milk yield and milk composition between treatments. It was concluded that moderate amounts of unsaturated plant oils can be added to dairy goat diets without negative effects on diet digestibility or performance traits

Effect of fat sources on fiber digestion in ruminants

El objetivo del presente trabajo fue revisar el efecto de la inclusión de fuentes de grasa no protegidas sobre la digestión de la fibra en los rumiantes. Es bien conocido que el aporte de grasa extra en forma de fuentes de grasa no protegidas a la dieta puede afectar negativamente a los microorganismos del rumen y, en consecuencia, a la digestión microbiana de la dieta. La bibliografía revisada indica que la fibra es el único componente de la dieta cuya digestibilidad es reducida en ocasiones. Este efecto es menos frecuente cuando el contenido de grasa extra en la dieta no supera el 4% con independencia del grado de insaturación, forma de presentación y procesado de la fuente de grasa. En los trabajos en que se observó reducción de la digestibilidad de la fibra aunque la inclusión de grasa extra en la dieta fue inferior al 4%, el forraje mayoritario aportado fue ensilado, o se utilizaron fuentes de grasa ricas en ácidos grasos poliinsaturados de más de 20 carbonos. Cuando la grasa extra se incluye por encima del 4% en la dieta, la reducción de la digestibilidad de la fibra es más frecuente pero no existe una relación clara entre los resultados observados y las características de la fuente de grasa o de la dieta. En ocasiones, la ausencia de efectos negativos de la grasa extra sobre la digestibilidad total de la fibra puede ser explicada porque la disminución de la digestión ruminal es compensada totalmente por la digestión en los tramos posteriores del tracto digestivo. El efecto negativo de las fuentes de grasa no protegidas sobre la digestibilidad de la fibra se relaciona con el efecto tóxico que los ácidos grasos insaturados de cadena larga tienen sobre las bacterias fibrolíticas y los protozoos ruminales, aunque el mecanismo de acción no ha sido aclarado.The aim of this paper was to review the effect of unprotected dietary lipid sources on fiber digestion in ruminants. It is well known that extra fat included in the diet in the form of unprotected fat sources sometimes can negatively affect rumen microorganisms and alter the microbial digestion of the diet. Reviewed literature points out fiber is the only dietary component whose digestibility can be decreased. This effect is less common when extra fat is included in the diet up to 4% regardless of unsaturation degree, and type or processing of the fat source. Decreased fiber digestibility observed in some studies where extra fat was lower than 4% could be due to the inclusion of silage as the main forage in the diet, or the use of fat sources rich in polyunsaturated fatty acids over 20 carbons. When extra fat is included in the diet above 4%, decreased fiber digestibility is more common but there is not clear relationship between the observed effect and the characteristics of the fat source or the diet. In some studies, the lack of negative effects of extra fat on total fiber digestibility could be explained because digestion in the lower digestive tract completely compensated for the decrease of rumen digestion. Decreased fiber digestibility when unprotected fat sources are included in ruminant diets is related to the toxic effect that long chain unsaturated fatty acids have on rumen fibrolytic bacteria and protozoa, although the exact mechanism of action has not been determined ye

Lipid metabolism in ruminants

El objetivo de este trabajo fue revisar algunos aspectos del metabolismo lipídico y características relevantes de la grasa de la carne y la leche de los rumiantes. Los ácidos grasos disponibles para la absorción en el intestino delgado de los rumiantes proceden de los alimentos y los microorganismos ruminales, y son mayoritariamente ácidos grasos saturados y no esterificados debido a la digestión microbiana ruminal. Los ácidos grasos absorbidos que tienen menos de 12 carbonos son vertidos directamente a la vena porta y transportados al hígado unidos a la albúmina sérica; el resto son esterificados e incorporados a lipoproteínas de muy baja densidad y quilomicrones que se transportan por vía linfática hasta el torrente sanguíneo para su distribución a los tejidos. El hígado de los rumiantes tiene menor importancia en el metabolismo lipídico que el de los monogástricos, pero adquiere especial relevancia en situaciones de balance energético negativo en las que la alteración del metabolismo hepático de los lípidos puede provocar graves patologías. Los depósitos grasos distintos de la musculatura están constituidos casi exclusivamente por triglicéridos y son la principal reserva de energía del organismo. Por el contrario, la grasa intramuscular posee distintas proporciones de fosfolípidos y triglicéridos en función del grado de engrasamiento. Los fosfolípidos de las membranas celulares son el lugar preferente de deposición de los ácidos grasos poliinsaturados disponibles. La composición de la grasa láctea varía en función del origen de los ácidos grasos: ácidos grasos de cadena larga de origen alimentario o movilizados desde el tejido adiposo, o ácidos grasos de cadena corta y media sintetizados in situ a partir de acetato y betahidroxibutirato. La mayor parte de los ácidos grasos incorporados a los triglicéridos lácteos son captados de la sangre. La importante contribución de los ácidos grasos de la dieta consumida por los rumiantes a los lípidos de sus productos ofrece la posibilidad de modificar el contenido de los ácidos grasos de la carne y, sobre todo, la leche en un sentido favorable para la salud de los consumidores.In this paper, key aspects of lipid metabolism and characteristics of ruminants’ meat and milk fat were reviewed. Fatty acids available for absorption in the small intestine of ruminants are from dietary and microbial origin and, because of microbial digestion in the rumen, are mainly nonsterified saturated fatty acids. Short chain fatty acids (less than 12 carbon atoms) are absorbed into the bloodstream, bound to serum albumin and transported to the liver through the portal vein. Medium and long chain fatty acids are esterified upon their absorption and transported via lymph to the bloodstream as chylomicrons and very low density lipoproteins, to be used by the different tissues. In ruminants, the liver has a minor role in lipid metabolism compared with monogastrics, but it is especially relevant in situations of intense negative energy balance when the hepatic metabolism of lipids may be altered causing severe pathologies. Fat depots other than intramuscular depots are composed mainly of triglycerides and are the major energy reserve of the body. However, the proportion of phospholipids and triglycerides in the intramuscular fat depends on the degree of fatness. The cell membrane phospholipids are the preferred site of deposition of available polyunsaturated fatty acids. Milk fat composition depends on the origin of the fatty acids: long chain fatty acids from dietary origin or mobilized from adipose tissue, or medium and short chain fatty acids synthesized in situ from acetate and betahydroxybutyrate. Most fatty acids incorporated into milk triglycerides are taken from the blood. The major contribution of dietary fatty acids to meat and, specially, milk fatty acids offers the possibility of changing the fatty acid profile of ruminant products to promote human consumer health

Probabilistic classification models for the in situ authentication of iberian pig carcasses using near infrared spectroscopy

Iberian pig ham is one of several high value European food products that are the subject of significant attempts at fraud because of the high price differences between commercial categories. Iberian pig products are classified by the Spanish regulations into different categories, mainly depending on the feeding regime during the fattening phase and the race involved, being of Premium quality those products obtained from the animals fed with acorns and other natural resources. Most of the previous NIRS studies related to the Iberian pig have involved the use of at-line instruments to predict quantitative quality parameters. This paper explores the use of the NIR spectra (369 for training and 199 for validation) to classify samples according to the categories Premium (animals fed with acorn) and Non Premium (animals fed with compound feeds), using a MicroNIR™ Pro1700 microspectrometer to analyse individual carcasses in situ at the slaughterhouse line. Four discriminant methods were explored: linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), Kernel Bayes and Logistic Regression. These are all discriminant methods that naturally produce classification probabilities to quantify the uncertainty of the results. Rules were tuned and methods compared using both classification error rates and a probability scoring rule. LDA gave the best results, attaining an overall accuracy of 93% and providing well-calibrated classification probabilities

Mechanism of action of drugs with activity against multicellular parasites

Parasiticides have been the most valuable weapons to combat parasites for almost half a century, constituting more than 50 % of veterinary pharmaceuticals and a good part of the products destined for human health. However, in many parts of the world, parasites develop resistance to these drugs, and it is now a major health problem. One way to avoid this inconvenience is the in-depth knowledge of its mechanisms of action, which will allow a more appropriate use. This work is a review of the different physiological aspects of parasite species and an explanation of the different mechanisms of action of antiparasitic agents. Once these drugs are ingested or absorbed by parasites the agents come into contact with the parasites structures, and according to the drug's properties it will define the antiparasitic activity either by altering tegument, carbohydrates, protein and lipid metabolism, or motility of the multicellular parasites.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

Short Communication: The potential of portable near infrared spectroscopy for assuring quality and authenticity in the food chain, using Iberian hams as an example

This communication assesses the use of a portable near infrared (NIR) instrument to measure quantitative (fatty acid profile) properties and qualitative (‘Premium’ and ‘Non-premium’) categories of individual Iberian pork carcasses at the slaughterhouse. Acorn-fed Iberian pigs have more unsaturated fats than pigs fed conventional compound feed. Recent advances in miniaturisation have led to a number of handheld NIR devices being developed, allowing processing decisions to be made earlier, significantly reducing time and costs. The most common methods used for assessing quality and authenticity of Iberian hams are analysis of the fatty acid composition of subcutaneous fat using gas chromatography and DNA analysis. In this study, NIR calibrations for fatty acids and classification as premium or non-premium ham, based on carcass fat measured in situ, were developed using a portable NIR spectrometer. The accuracy of the quantitative equations was evaluated through the standard error of cross validation or standard error of prediction of 0.84 for palmitic acid (C16:0), 0.94 for stearic acid (C18:0), 1.47 for oleic acid (C18:1) and 0.58 for linoleic acid (C18:2). Qualitative calibrations provided acceptable results, with up to 98% of samples (n = 234) correctly classified with probabilities ⩾0.9. Results indicated a portable NIR instrument has the potential to be used to measure quality and authenticity of Iberian pork carcasses

Multistage and adaptive sampling protocols combined with near-infrared spectral sensors for automated monitoring of raw materials in bulk

A near-infrared (NIR) spectroscopy-based real-time monitoring system is proposed to sample and analyse agro-industrial raw materials transported in bulk in a single stage, easing and optimising the evaluation process of incoming lots at reception of agri-food plants. NIR analysis allows rapid and cost-effective analytical results to be obtained, and hence to rethink current sampling protocols. For this purpose, multistage and adaptive sampling designs were tested in this paper, which have been reported (in soil science and ecology) to be more flexible and efficient than conventional strategies to study patterns of clustering or patchiness, which can be the result of natural phenomena. The additional spatial information provided by NIR has also been exploited, using geostatistical analysis to model the spatial pattern of key analytical constituents in Processed Animal Proteins (PAPs). This study addresses the assessment of two kinds of quality/safety issues in PAP lots – moisture accumulation and cross-contamination. After a simulation study, qualitative and quantitative analyses were carried out to make a performance comparison between sampling designs. Results show that sampling densities below 10–15% demonstrated higher estimation errors, failing to represent the actual spatial patterns, while a stratified adaptive cluster sampling design achieved the best performance

From CO2 to Value-Added Products: A Review about Carbon-Based Materials for Electro-Chemical CO2 Conversion

This research was funded by Spanish Ministry of Science, Innovation and Universities, grant number RTI2018-099224-B-I00; and Junta de Andalucía, grant numbers P12-RNM-2892, P18- RTJ-2974 and RNM172. L.D.R.V. was funded by MINCIENCIAS.Data sharing not applicable.The authors thank the financial support of the Spanish Ministry of Science, Innovation and Universities (project RTI2018-099224-B-I00) and Junta de Andalucía (Project P12- RNM-2892, P18-RTJ-2974 and RNM172). L.D. Ramírez-Valencia is grateful to the Colombian Ministry of Sciences, Technology and Innovation (MINCIENCIAS) for supporting her PhD studies.The global warming and the dangerous climate change arising from the massive emission of CO2 from the burning of fossil fuels have motivated the search for alternative clean and sustainable energy sources. However, the industrial development and population necessities make the decoupling of economic growth from fossil fuels unimaginable and, consequently, the capture and conversion of CO2 to fuels seems to be, nowadays, one of the most promising and attractive solutions in a world with high energy demand. In this respect, the electrochemical CO2 conversion using renewable electricity provides a promising solution. However, faradaic efficiency of common electro-catalysts is low, and therefore, the design of highly selective, energy-efficient, and cost-effective electrocatalysts is critical. Carbon-based materials present some advantages such as relatively low cost and renewability, excellent electrical conductivity, and tunable textural and chemical surface, which show them as competitive materials for the electro-reduction of CO2. In this review, an overview of the recent progress of carbon-based electro-catalysts in the conversion of CO2 to valuable products is presented, focusing on the role of the different carbon properties, which provides a useful understanding for the materials design progress in this field. Development opportunities and challenges in the field are also summarized.Spanish Ministry of Science, Innovation and Universities RTI2018-099224-B-I00Junta de Andalucia P12-RNM-2892 P18RTJ-2974 RNM17