ABSTRACT: The aim of this study was to determine external and internal quality parameters of industrial (cages and cage-free) and family farms eggs that are normally available at groceries in developing countries such as Chile. Two experiments were performed to evaluate 1) quality differences between family farms and industrial eggs and 2) to determine quality differences between brown shell eggs from different industrial cage and cage-free systems. Experiment 1 consisted of five groups where three of them were industrial eggs: i) cage white shell eggs, ii) cage brown shell eggs, iii) brown shell cage-free eggs; and two of them were non-industrial: iv) family farm brown shell eggs and v) family farm blue shell eggs. Experiment 2 had four groups, all brown-shell types of eggs were used: i) cage brown eggs, ii) cage-free from aviary eggs, iii) southern free-range eggs and iv) central free-range eggs. In both Experiments, egg weight, egg length, egg width, egg shape index, Haugh units, albumen ratio, egg yolk, yolk weight and albumen weight, blood and meat spots were determined. In Experiment 1, brown and blue-shelled family farm eggs were equal in terms of external and internal quality, except for blood spots, with brown eggs having more incidence. In Experiment 2, free-range eggs presented more intense yolk colors compared to those from battery and cages. In both experiments, free-range eggs presented the darker yolk color. It can be concluded that brown and blue-shelled family farm eggs are equal in terms of external and internal quality, except for blood spots, with brown eggs having more incidence. In addition, free-range eggs from the southern part of the country presented better shell quality, whereas free-range eggs presented more intense yolk colors, while those of battery.

Nutritional recommendations of the past 35-40 years have promoted the reduction of fat intake, calories and particularly saturated fatty acids (SFA), emphasizing lower consumption of red meat and high fat dairy products, because of its association with cardiovascular diseases (CVD), being in turn replaced by sugars and refined carbohydrates. There is consensus that the SFA concentration in blood plasma, particularly palmitic acid, are associated with an increased risk of CVD and heart attacks. However, there is no evidence of causality between CVD and consumption of SFA, raising reasonable doubts about the relation ship between consumption of SFA with those present in blood plasma, as well as with the CVD risk. This review presents scientific evidence that demonstrates that the inclusion of fats in the diet, specifically animal fats from ruminants, provide important health benefits for people, especially when accompanied by a reduction in the consumption of carbohydrates. It is also proposed that ruminant products and their fatty acids contribute with beneficial saturated fats for people's health, especially those from pastoral production systems such as vaccenic, rumenic and linolenic acids.

Las recomendaciones nutricionales de los últimos 40 años han promovido la reducción del consumo grasas, calorías y particularmente ácidos grasos saturados (AGS), enfatizando un menor consumo de carnes rojas y productos lácteos altos en materia grasa debido a su asociación con enfermedades cardiovasculares (ECV), siendo reemplazados por azúcares y carbohidratos refinados. Existe consenso en que la concentración de AGS en el plasma sanguíneo, particularmente ácido palmítico, se asocia con un mayor riesgo de ECV y ataques al corazón. Sin embargo, no hay evidencias de causalidad entre ECV y consumo de AGS, planteando dudas razonables sobre la existencia de una relación entre el consumo de AGS con los presentes en el plasma sanguíneo, y con el riesgo de ECV. La presente revisión plantea evidencia científica que demuestra que la incorporación de grasas en la dieta, específicamente grasas de origen animal, aporta importantes beneficios para la salud de las personas, en especial cuando se acompaña de una reducción en el consumo de carbohidratos. Asimismo, se plantea que los productos de rumiantes y sus grasas contribuyen con ácidos grasos beneficiosos para la salud de las personas, en especial aquellos provenientes de sistemas de producción pastoriles como los ácidos vaccénico, ruménico y linolénico.

Botanical composition affects the nutritive value and nutrient degradation kinetics of pastures. However, there is little information about pastures composed of various species. The present study was conducted to evaluate in situ degradation kinetics of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of a naturalized non fertilized pasture (NNF), naturalized fertilized pasture (NF), sown pasture with Lolium perenne L. and Trifolium repens L. (RGWC), and sown pasture with Bromus valdivianus Phil., Dactylis glomerata L., Holcus lanatus L., L. perenne and T. repens (MIXED); at three dates of harvest (early-spring, mid-spring and autumn). Duplicate bags were incubated in the rumen of three cannulated cows for 2, 4, 8, 12, 24 or 48 h. Zero-hour bags were washed with water. Ruminal degradation was evaluated according to exponential models with or without lag phase. Pasture chemical composition showed on average low DM, high CP and digestible organic matter (DOMD). Degradation parameters of DM, CP and NDF exhibited strong pasture type*date of harvest interactions. In general, high potential degradability and fractional degradation rates of DM, CP and NDF were observed. Nutrient supply was generally higher for RGWC and NF, especially compared with NNF during autumn. Naturalized fertilized pastures supply similar amounts of nutrients to grazing cattle as sown pastures. However, it is necessary to consider other variables that determine the productive performance such as DM intake and rumen fermentation products.

Grazing dairy cows are characterized by converting a low proportion of dietary N into milk N. This low N use efficiency (NUE) is mainly due to an excessive supply of crude protein (CP) of pasture with regard to animal requirements. Excess N in the diet has negative effects for the animal; it alters the organoleptic characteristics of milk and pollutes the environment through N excretions. The aim of this review was to analyze the available information on nutritional strategies to improve NUE by grazing dairy cows, such as diluting the dietary N through supplementation, synchronizing ruminal carbohydrate (CHO), and N fermentation rates, and using pastures with a high water soluble carbohydrates (WSC) content. There is a beneficial effect of carbohydrate supplementation on NUE, with an increase in milk yield (MY) of 0.83 ± 0.34 kg milk kg-1 supplement and a reduction of ammonia N (NH3-N) in the rumen. A better synchrony between CHO and rumen N does not improve MY and NUE. However, a positive effect on NUE was identified as a result of increasing the WSC/CP ratio. The use of cultivars with high WSC content increases the dry matter intake (DMI), MY, and milk N production, with no consistent effect on NUE.

Las vacas lecheras en pastoreo se caracterizan por convertir una baja cantidad del N dietario en N lácteo. Esta baja eficiencia en el uso del N (NUE) se debe principalmente al excesivo suministro de proteína cruda (CP) de la pradera en relación a los requerimientos del animal. El exceso de N en la dieta tiene efectos negativos para el animal, altera las características organolépticas de la leche y contamina el medio ambiente a través de las excreciones de N. El objetivo de este trabajo fue analizar la información disponible sobre estrategias nutricionales para mejorar EUN en vacas lecheras a pastoreo, tales como diluir la concentración de N dietario a través de la suplementación, sincronizar la tasa de fermentación de carbohidratos (CHO) y N en el rumen, y utilizar praderas con alto contenido de carbohidratos solubles (WSC). Se observa una relación beneficiosa entre la suplementación con CHO y la NUE, con un aumento en producción de leche (MY) de 0.83 ± 0.34 kg leche kg-1 suplemento y menor cantidad de N amoniacal (N-NH3) en el rumen. La mejora en la sincronía entre CHO y N a nivel ruminal, no genera los efectos esperados en PL y EUN. Se observó un efecto positivo sobre la NUE al mejorar la relación WSC/CP. La utilización de cultivares con un mayor contenido de WSC incrementa el consumo de MS, MY y la cantidad de N lácteo, mientras que la NUE no mejora consistentemente.