Effects of the feed : Water mixing proportion on diet digestibility of growing pigs

Funding: This research was funded by Spanish Ministry of Science and Innovation (CDTI project IDI-20110003), and TEM 2010 research grant form "Comissionat per a Universitats I Recerca del Departament d'Innovació, Universitats I empresa form Generalitat de Catalunya (AGAUR).The effect of different water-to-feed ratios on apparent total tract digestibility of energy and nutrients were evaluated in growing-finishing pigs. In trial 1 (26 d), 16 female pigs (46.7 ± 1.98 kg of body weight, BW) were individually assigned to four treatments (n = 4). In trial 1, pigs were fed a control diet in dry form (CON) and in blend form with water-to-feed ratios of 0.6:1, 2.1:1 and 2.7:1. In trial 2 (26 d), rearranged animals (65.4 ± 3.14 kg of BW) were assigned a control diet in dry form (CON) and ratios of 1.35:1, 2.7:1 and 3.5:1. In trial 1, pigs fed on ratios of 2.1:1 and 2.7:1 had a higher organic matter digestibility (OMd) and gross energy digestibility (GEd) than CON. In trial 2, pigs fed on ratios of 1.35:1, 2.7:1, and 3.5:1 had a higher OMd and GEd than CON. Quadratic regressions showed the maximum dilution rate to reach higher digestibility coefficients at 1.83:1 and at 2.7:1 for trials 1 and 2, respectively. During trial 1, pigs on the 0.6:1 dilution rate had higher weight gain than those on CON. The water-to-feed ratio that optimized OM and GE digestibility may increase with the age of the pigs

Impact of Dietary Supplementation with Sodium Butyrate Protected by Medium-Chain Fatty Acid Salts on Gut Health of Broiler Chickens

This research was co-funded by the European Fund of Regional Development of the European Union within the framework of the FEDER operating program of Catalunya 2014-2020 (project COMRDI16-1-0033) and managed by ACCIÓ.Nutritional strategies to improve gut health of broilers are under research. This study investigated the effect of dietary supplementation with sodium butyrate protected by sodium salts of medium-chain fatty acids as a feed additive on broiler gut health. The first experiment was conducted to evaluate the effect of supplementing at 0.5, 1, and 2 kg/t in broilers housed under optimal conditions. Supplementation at 0.5 and 1 kg/t maintained goblet cell counts at 10 days of age (p ≤ 0.05), and supplementation at 1 kg/t decreased intraepithelial lymphocyte counts compared to 2 kg/t at 39 days (p ≤ 0.10). Abdominal fat pad levels of lauric and myristic acids were gradually increased by supplement dose (p ≤ 0.05). In the second experiment, the feed additive at 1 kg/t was evaluated in coccidiosis-challenged broilers. Experimental treatments were as follows: non-challenged, control-challenged, and supplemented-challenged treatments. Coccidiosis negatively impact performance and modify histomorphometry and microbiota (p ≤ 0.05). The feed additive increased crypt depth at 7 days post-inoculation and goblet cell count at 14 days post-inoculation (p ≤ 0.05). Further, supplementation interacted with the microbiota modification led by the coccidiosis (p ≤ 0.05). These results suggest that this feed additive could be a useful strategy to reinforce the gut barrier, especially for birds under coccidiosis-challenge treatments

Effectiveness, cost-utility, and benefits of a multicomponent therapy to improve the quality of life of patients with fibromyalgia in primary care : a mixed methods study protocol

Introduction:Fibromyalgia (FM) is a chronic condition characterized by chronic pain, fatigue and loss of function which significantly impairs quality of life. Although treatment of FM remains disputed, some studies point at the efficacy of interdisciplinary therapy. This study aims to analyze the effectiveness, cost-utility and benefits of a multicomponent therapy on quality of life (main variable), functional impact, mood and pain in people suffering from FM that attend primary care centers (PCCs) of the Catalan Institute of Health (ICS).Methods and analysis:A 2-phase, mixed methods study has been designed following Medical Research Council guidance. Phase 1: Pragmatic randomized clinical trial with patients diagnosed with FM that attend one of the 11 PCCs of the ICS Gerència Territorial Terres de l'Ebre. We estimate a total sample of 336 patients. The control group will receive usual clinical care, while the multicomponent therapy group (MT group) will receive usual clinical care plus group therapy (consisting of health education, exercise and cognitive-behavioural therapy) during 12 weeks in 2-hourly weekly sessions. Analysis: the standardized mean response and the standardized effect size will be assessed at 3, 9, and 15 months after the beginning of the study using multiple linear regression models. Utility measurements will be used for the economic analysis. Phase 2: Qualitative socio constructivist study to evaluate the intervention according to the results obtained and the opinions and experiences of participants (patients and professionals). We will use theoretical sampling, with 2 discussion groups of participants in the multicomponent therapy and 2 discussion groups of professionals of different PCCs. A thematic content analysis will be carried out.Ethics and dissemination:This study protocol has been approved by the Clinical Research Ethics Committee of the Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (code P18/068). Articles will be published in international, peer-reviewed scientific journals.Trial registration:Clinical-Trials.gov: NCT04049006

Effectiveness, cost-utility, and benefits of a multicomponent therapy to improve the quality of life of patients with fibromyalgia in primary care: A mixed methods study protocol

Introduction: Fibromyalgia (FM) is a chronic condition characterized by chronic pain, fatigue and loss of function which significantly impairs quality of life. Although treatment of FM remains disputed, some studies point at the efficacy of interdisciplinary therapy. This study aims to analyze the effectiveness, cost-utility and benefits of a multicomponent therapy on quality of life (main variable), functional impact, mood and pain in people suffering from FM that attend primary care centers (PCCs) of the Catalan Institute of Health (ICS). Methods and analysis: A 2-phase, mixed methods study has been designed following Medical Research Council guidance. Phase 1: Pragmatic randomized clinical trial with patients diagnosed with FM that attend one of the 11 PCCs of the ICS Gerència Territorial Terres de l'Ebre. We estimate a total sample of 336 patients. The control group will receive usual clinical care, while the multicomponent therapy group (MT group) will receive usual clinical care plus group therapy (consisting of health education, exercise and cognitive-behavioural therapy) during 12 weeks in 2-hourly weekly sessions. Analysis: the standardized mean response and the standardized effect size will be assessed at 3, 9, and 15 months after the beginning of the study using multiple linear regression models. Utility measurements will be used for the economic analysis. Phase 2: Qualitative socio constructivist study to evaluate the intervention according to the results obtained and the opinions and experiences of participants (patients and professionals). We will use theoretical sampling, with 2 discussion groups of participants in the multicomponent therapy and 2 discussion groups of professionals of different PCCs. A thematic content analysis will be carried out. Ethics and dissemination: This study protocol has been approved by the Clinical Research Ethics Committee of the Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (code P18/068). Articles will be published in international, peer-reviewed scientific journals

Utilización de subproductos agroindustriales en alimentación líquida para cerdos de engorde

La alimentación líquida (AL) se ha empleado en alimentación porcina desde hace varias décadas obteniendo en gran parte, resultados productivos satisfactorios comparados con la alimentación en seco. Uno de los factores que mayor efecto muestra sobre los resultados es el ratio de dilución de la mezcla. Por otra parte, el máximo provecho económico del sistema de AL se obtiene cuando se introducen subproductos de bajo coste a la dieta. La utilización efectiva de subproductos tropieza con su alta variabilidad, dificultades logísticas de aprovisionamiento, escaso conocimiento nutricional y condiciones de utilización práctica en alimentación porcina. En este contexto, el objetivo general de la presente tesis doctoral ha sido contribuir a optimizar el funcionamiento del sistema de AL instalado en una granja comercial y estudiar el valor nutricional de subproductos de proximidad para su uso en la AL de cerdos de engorde. Para ello se llevaron a cabo cuatro estudios. En el primer estudio (Capítulo 4) se identificaron varios subproductos agroindustriales y se seleccionaron aquellos más prometedores. De los subproductos seleccionados, la mayonesa y la harina de almendra se introdujeron en las dietas a bajos niveles de inclusión (7,75% y 10%, respectivamente) y se evaluaron los rendimientos productivos de los cerdos y el ahorro económico en el coste del pienso. Se observó que la introducción de la mayonesa redujo el costo del pienso en un 15% y la harina de almendra en un 10%, sin empeorar significativamente los rendimientos productivos. Con el fin de evaluar en más profundidad el valor nutritivo de algunos de los subproductos seleccionados en el Capítulo 4, se llevaron a cabo pruebas de digestibilidad in vivo para evaluar el contenido energético y nivel máximo de inclusión (sólo en algunos casos) de todos los subproductos (Capítulo 5). Los resultados del estudio de digestibilidad in vivo por diferencia de la materia orgánica (dMO) y de la energía (dEB) de la galleta líquida, el bagazo de cerveza, la harina zootécnica y el pastone determinada utilizando un 50% de inclusión de subproducto en la dieta y una ratio de dilución 2,7:1 (agua:materia seca), no se vio alterada por el nivel de inclusión del subproducto en la ración. Por otra parte, la dMO y la dEB de la mayonesa, la harina de almendra, la harina de cacao y el kiwi se estudió por regresión mediante cuatro niveles de inclusión (2, 4, 7 y 10%; y 4, 8, 12 y 16% para el kiwi), al ser considerados subproductos menos convencionales y de mayor riesgo. La evolución de la digestibilidad del extracto etéreo sugirió que el nivel máximo de inclusión de la mayonesa en la dieta no debería sobrepasar el 8,5%; o el 6,1% para la harina de almendra. La evolución de la digestibilidad de otros nutrientes (p. ej. Fibra Bruta) recomiendan utilizar la harina de cacao y el kiwi con cautela. En el tercer estudio (Capitulo 6), se decidió buscar métodos alternativos, menos costosos y laboriosos a la utilización de animales, y construir ecuaciones de predicción de la digestibilidad de la materia orgánica y energía y del contenido energético, energía digestible y energía metabolizable de los subproductos evaluados en el Capítulo 5. Finalmente, en el último estudio (Capítulo 7), se evaluó en animales de diferentes edades un amplio rango de ratios de dilución (0:1, pienso seco, y 0,6:1, 1,5:1, 2,1:1, 2,7:1 and 3,5:1) para determinar aquellos que optimizan la digestibilidad de la ración y, en menor medida también, los rendimientos productivos. Se observó que las diluciones más bajas (ratio 1,83:1; agua:pienso) son más apropiadas para los animales jóvenes y más altas (ratio 2,7:1) para los animales de final de engorde.The liquid feed (LF) has been used in swine production for several decades obtaining satisfactory production results compared with dry feed. One of the factors that affect those results is the dilution ratio of the mixture. Moreover, the maximum economic benefit of the LF systems is obtained when cheaper by-products are introduced into the diet. Effective utilization of by-products is hampered by its high variability, logistical supply difficulties, scarce nutritional knowledge and practical conditions of use in swine nutrition. In this context, the main objective of this PhD Thesis has been to contribute to optimize the performance of LF system installed in a commercial farm and study the nutritional value of near to the farm by-products for use in liquid feeding fattening pigs. To this purpose, four studies were conducted. In the first study (Chapter 4) several agro-industrial by-products were identified and those most promising were selected. Among selected products, mayonnaise and almond meal were introduced into the LF diets at low levels of inclusion (7.75% and 10%, respectively) and growth performance of pigs and economic benefits of feed costs were assessed. It was observed that the introduction of mayonnaise reduced feed costs by 15% and by 10% for almond meal, without significantly impairing performance results. In order to assess in more detail the nutritional value of some by-products selected in Chapter 4, there were carried out in vivo digestibility trials to evaluate the energy content and the maximum level of inclusion (in some cases) of all by-products (Chapter 5) . The results of in vivo digestibility by difference method of organic matter (OMd) and energy (GEd) of the liquid bakery by-product, brewers grains, hominy feed and high-moisture corn using a 50% of by-product inclusion into diet and at water-to-feed ratio 2.7:1 (water:dry matter), were not altered by the inclusion level of by-product into the diet. On the other hand, OMd and GEd of mayonnaise, almond meal, cocoa meal and kiwi was studied by regression method through four levels of inclusion (2, 4, 7 and 10%; and 4, 8, 12 and 16% for kiwi), being considered less conventional and riskier by-products. The evolution of ether extract digestibility suggested that the maximum level of inclusion of mayonnaise in the diet should not exceed 8.5%; or 6.1% for almond flour. The evolution of the digestibility of the other nutrients (i.e. Crude Fiber) recommended using cocoa meal and kiwi with caution. In the third study (Chapter 6), it was decided to seek alternative methods, less costly and laborious to than using live animals, and to perform prediction equations for organic matter and energy digestibility and energy content, digestible energy and metabolizable energy of agro-industrial by-products assessed in Chapter 5. Finally, in the last study (Chapter 7), it was evaluated in animals of different ages a wide range of dilution ratios (0:1, dry feed, and 0.6:1, 1.5:1, 2.1:1, 2.7:1 and 3.5:1) to determine those that optimize the digestibility of the ration and, to a lesser extent, performance results. It was shown that the lower dilutions (ratio 1.83:1, water:feed) are more appropriate for young animals and higher ratios (ratio 2.7:1) for fattening pigs

Utilización de subproductos agroindustriales en alimentación líquida para cerdos de engorde

La alimentación líquida (AL) se ha empleado en alimentación porcina desde hace varias décadas obteniendo en gran parte, resultados productivos satisfactorios comparados con la alimentación en seco. Uno de los factores que mayor efecto muestra sobre los resultados es el ratio de dilución de la mezcla. Por otra parte, el máximo provecho económico del sistema de AL se obtiene cuando se introducen subproductos de bajo coste a la dieta. La utilización efectiva de subproductos tropieza con su alta variabilidad, dificultades logísticas de aprovisionamiento, escaso conocimiento nutricional y condiciones de utilización práctica en alimentación porcina. En este contexto, el objetivo general de la presente tesis doctoral ha sido contribuir a optimizar el funcionamiento del sistema de AL instalado en una granja comercial y estudiar el valor nutricional de subproductos de proximidad para su uso en la AL de cerdos de engorde. Para ello se llevaron a cabo cuatro estudios. En el primer estudio (Capítulo 4) se identificaron varios subproductos agroindustriales y se seleccionaron aquellos más prometedores. De los subproductos seleccionados, la mayonesa y la harina de almendra se introdujeron en las dietas a bajos niveles de inclusión (7,75% y 10%, respectivamente) y se evaluaron los rendimientos productivos de los cerdos y el ahorro económico en el coste del pienso. Se observó que la introducción de la mayonesa redujo el costo del pienso en un 15% y la harina de almendra en un 10%, sin empeorar significativamente los rendimientos productivos. Con el fin de evaluar en más profundidad el valor nutritivo de algunos de los subproductos seleccionados en el Capítulo 4, se llevaron a cabo pruebas de digestibilidad in vivo para evaluar el contenido energético y nivel máximo de inclusión (sólo en algunos casos) de todos los subproductos (Capítulo 5). Los resultados del estudio de digestibilidad in vivo por diferencia de la materia orgánica (dMO) y de la energía (dEB) de la galleta líquida, el bagazo de cerveza, la harina zootécnica y el pastone determinada utilizando un 50% de inclusión de subproducto en la dieta y una ratio de dilución 2,7:1 (agua:materia seca), no se vio alterada por el nivel de inclusión del subproducto en la ración. Por otra parte, la dMO y la dEB de la mayonesa, la harina de almendra, la harina de cacao y el kiwi se estudió por regresión mediante cuatro niveles de inclusión (2, 4, 7 y 10%; y 4, 8, 12 y 16% para el kiwi), al ser considerados subproductos menos convencionales y de mayor riesgo. La evolución de la digestibilidad del extracto etéreo sugirió que el nivel máximo de inclusión de la mayonesa en la dieta no debería sobrepasar el 8,5%; o el 6,1% para la harina de almendra. La evolución de la digestibilidad de otros nutrientes (p. ej. Fibra Bruta) recomiendan utilizar la harina de cacao y el kiwi con cautela. En el tercer estudio (Capitulo 6), se decidió buscar métodos alternativos, menos costosos y laboriosos a la utilización de animales, y construir ecuaciones de predicción de la digestibilidad de la materia orgánica y energía y del contenido energético, energía digestible y energía metabolizable de los subproductos evaluados en el Capítulo 5. Finalmente, en el último estudio (Capítulo 7), se evaluó en animales de diferentes edades un amplio rango de ratios de dilución (0:1, pienso seco, y 0,6:1, 1,5:1, 2,1:1, 2,7:1 and 3,5:1) para determinar aquellos que optimizan la digestibilidad de la ración y, en menor medida también, los rendimientos productivos. Se observó que las diluciones más bajas (ratio 1,83:1; agua:pienso) son más apropiadas para los animales jóvenes y más altas (ratio 2,7:1) para los animales de final de engorde.The liquid feed (LF) has been used in swine production for several decades obtaining satisfactory production results compared with dry feed. One of the factors that affect those results is the dilution ratio of the mixture. Moreover, the maximum economic benefit of the LF systems is obtained when cheaper by-products are introduced into the diet. Effective utilization of by-products is hampered by its high variability, logistical supply difficulties, scarce nutritional knowledge and practical conditions of use in swine nutrition. In this context, the main objective of this PhD Thesis has been to contribute to optimize the performance of LF system installed in a commercial farm and study the nutritional value of near to the farm by-products for use in liquid feeding fattening pigs. To this purpose, four studies were conducted. In the first study (Chapter 4) several agro-industrial by-products were identified and those most promising were selected. Among selected products, mayonnaise and almond meal were introduced into the LF diets at low levels of inclusion (7.75% and 10%, respectively) and growth performance of pigs and economic benefits of feed costs were assessed. It was observed that the introduction of mayonnaise reduced feed costs by 15% and by 10% for almond meal, without significantly impairing performance results. In order to assess in more detail the nutritional value of some by-products selected in Chapter 4, there were carried out in vivo digestibility trials to evaluate the energy content and the maximum level of inclusion (in some cases) of all by-products (Chapter 5) . The results of in vivo digestibility by difference method of organic matter (OMd) and energy (GEd) of the liquid bakery by-product, brewers grains, hominy feed and high-moisture corn using a 50% of by-product inclusion into diet and at water-to-feed ratio 2.7:1 (water:dry matter), were not altered by the inclusion level of by-product into the diet. On the other hand, OMd and GEd of mayonnaise, almond meal, cocoa meal and kiwi was studied by regression method through four levels of inclusion (2, 4, 7 and 10%; and 4, 8, 12 and 16% for kiwi), being considered less conventional and riskier by-products. The evolution of ether extract digestibility suggested that the maximum level of inclusion of mayonnaise in the diet should not exceed 8.5%; or 6.1% for almond flour. The evolution of the digestibility of the other nutrients (i.e. Crude Fiber) recommended using cocoa meal and kiwi with caution. In the third study (Chapter 6), it was decided to seek alternative methods, less costly and laborious to than using live animals, and to perform prediction equations for organic matter and energy digestibility and energy content, digestible energy and metabolizable energy of agro-industrial by-products assessed in Chapter 5. Finally, in the last study (Chapter 7), it was evaluated in animals of different ages a wide range of dilution ratios (0:1, dry feed, and 0.6:1, 1.5:1, 2.1:1, 2.7:1 and 3.5:1) to determine those that optimize the digestibility of the ration and, to a lesser extent, performance results. It was shown that the lower dilutions (ratio 1.83:1, water:feed) are more appropriate for young animals and higher ratios (ratio 2.7:1) for fattening pigs

Short Communication : Evaluation of Intestinal Release of Butyric Acid from Sodium Butyrate Protected by Salts of Medium-Chain Fatty Acids in Broiler Chickens

Butyric acid has received great attention as a feed additive to maintain or increase the gut integrity and health of broiler chickens. Particularly, the protection of butyrate is under research to allow slow intestinal release of butyric acid and to promote its beneficial effects throughout the intestine. This study evaluated in vivo the intestinal release of butyric acid from sodium butyrate protected by salts of medium-chain fatty acid in broilers. Brilliant blue was used as an inert marker, so it was included in the feed additive that broilers ingested for two days. The gastrointestinal tract was then colored in blue from jejunum and backward. Considering the digesta color of the broilers non-supplemented as blank, it allowed quantification of the amount of brilliant blue, and consequently, butyric acid delivered in the intestine from the protected feed additive. Few traces of butyric acid were released in the duodenum and proximal jejunum, whereas the major amount (45.9%) was delivered in the distal ileum (p < 0.001). These results suggest that this in vivo approach allows for evaluation of the intestinal delivery of butyric acid supplemented as protected sodium butyrate by medium-chain fatty acids, showing a gradual intestinal release of butyric acid in broiler chickens

Short Communication: Evaluation of Intestinal Release of Butyric Acid from Sodium Butyrate Protected by Salts of Medium-Chain Fatty Acids in Broiler Chickens

Butyric acid has received great attention as a feed additive to maintain or increase the gut integrity and health of broiler chickens. Particularly, the protection of butyrate is under research to allow slow intestinal release of butyric acid and to promote its beneficial effects throughout the intestine. This study evaluated in vivo the intestinal release of butyric acid from sodium butyrate protected by salts of medium-chain fatty acid in broilers. Brilliant blue was used as an inert marker, so it was included in the feed additive that broilers ingested for two days. The gastrointestinal tract was then colored in blue from jejunum and backward. Considering the digesta color of the broilers non-supplemented as blank, it allowed quantification of the amount of brilliant blue, and consequently, butyric acid delivered in the intestine from the protected feed additive. Few traces of butyric acid were released in the duodenum and proximal jejunum, whereas the major amount (45.9%) was delivered in the distal ileum (p &lt; 0.001). These results suggest that this in vivo approach allows for evaluation of the intestinal delivery of butyric acid supplemented as protected sodium butyrate by medium-chain fatty acids, showing a gradual intestinal release of butyric acid in broiler chickens

Utilización de subproductos agroindustriales en alimentación líquida para cerdos de engorde /

Departament responsable de la tesi: Departament de Ciència Animal i Dels AlimentsLa alimentación líquida (AL) se ha empleado en alimentación porcina desde hace varias décadas obteniendo en gran parte, resultados productivos satisfactorios comparados con la alimentación en seco. Uno de los factores que mayor efecto muestra sobre los resultados es el ratio de dilución de la mezcla. Por otra parte, el máximo provecho económico del sistema de AL se obtiene cuando se introducen subproductos de bajo coste a la dieta. La utilización efectiva de subproductos tropieza con su alta variabilidad, dificultades logísticas de aprovisionamiento, escaso conocimiento nutricional y condiciones de utilización práctica en alimentación porcina. En este contexto, el objetivo general de la presente tesis doctoral ha sido contribuir a optimizar el funcionamiento del sistema de AL instalado en una granja comercial y estudiar el valor nutricional de subproductos de proximidad para su uso en la AL de cerdos de engorde. Para ello se llevaron a cabo cuatro estudios. En el primer estudio (Capítulo 4) se identificaron varios subproductos agroindustriales y se seleccionaron aquellos más prometedores. De los subproductos seleccionados, la mayonesa y la harina de almendra se introdujeron en las dietas a bajos niveles de inclusión (7,75% y 10%, respectivamente) y se evaluaron los rendimientos productivos de los cerdos y el ahorro económico en el coste del pienso. Se observó que la introducción de la mayonesa redujo el costo del pienso en un 15% y la harina de almendra en un 10%, sin empeorar significativamente los rendimientos productivos. Con el fin de evaluar en más profundidad el valor nutritivo de algunos de los subproductos seleccionados en el Capítulo 4, se llevaron a cabo pruebas de digestibilidad in vivo para evaluar el contenido energético y nivel máximo de inclusión (sólo en algunos casos) de todos los subproductos (Capítulo 5). Los resultados del estudio de digestibilidad in vivo por diferencia de la materia orgánica (dMO) y de la energía (dEB) de la galleta líquida, el bagazo de cerveza, la harina zootécnica y el pastone determinada utilizando un 50% de inclusión de subproducto en la dieta y una ratio de dilución 2,7:1 (agua:materia seca), no se vio alterada por el nivel de inclusión del subproducto en la ración. Por otra parte, la dMO y la dEB de la mayonesa, la harina de almendra, la harina de cacao y el kiwi se estudió por regresión mediante cuatro niveles de inclusión (2, 4, 7 y 10%; y 4, 8, 12 y 16% para el kiwi), al ser considerados subproductos menos convencionales y de mayor riesgo. La evolución de la digestibilidad del extracto etéreo sugirió que el nivel máximo de inclusión de la mayonesa en la dieta no debería sobrepasar el 8,5%; o el 6,1% para la harina de almendra. La evolución de la digestibilidad de otros nutrientes (p. ej. Fibra Bruta) recomiendan utilizar la harina de cacao y el kiwi con cautela. En el tercer estudio (Capitulo 6), se decidió buscar métodos alternativos, menos costosos y laboriosos a la utilización de animales, y construir ecuaciones de predicción de la digestibilidad de la materia orgánica y energía y del contenido energético, energía digestible y energía metabolizable de los subproductos evaluados en el Capítulo 5. Finalmente, en el último estudio (Capítulo 7), se evaluó en animales de diferentes edades un amplio rango de ratios de dilución (0:1, pienso seco, y 0,6:1, 1,5:1, 2,1:1, 2,7:1 and 3,5:1) para determinar aquellos que optimizan la digestibilidad de la ración y, en menor medida también, los rendimientos productivos. Se observó que las diluciones más bajas (ratio 1,83:1; agua:pienso) son más apropiadas para los animales jóvenes y más altas (ratio 2,7:1) para los animales de final de engorde.The liquid feed (LF) has been used in swine production for several decades obtaining satisfactory production results compared with dry feed. One of the factors that affect those results is the dilution ratio of the mixture. Moreover, the maximum economic benefit of the LF systems is obtained when cheaper by-products are introduced into the diet. Effective utilization of by-products is hampered by its high variability, logistical supply difficulties, scarce nutritional knowledge and practical conditions of use in swine nutrition. In this context, the main objective of this PhD Thesis has been to contribute to optimize the performance of LF system installed in a commercial farm and study the nutritional value of near to the farm by-products for use in liquid feeding fattening pigs. To this purpose, four studies were conducted. In the first study (Chapter 4) several agro-industrial by-products were identified and those most promising were selected. Among selected products, mayonnaise and almond meal were introduced into the LF diets at low levels of inclusion (7.75% and 10%, respectively) and growth performance of pigs and economic benefits of feed costs were assessed. It was observed that the introduction of mayonnaise reduced feed costs by 15% and by 10% for almond meal, without significantly impairing performance results. In order to assess in more detail the nutritional value of some by-products selected in Chapter 4, there were carried out in vivo digestibility trials to evaluate the energy content and the maximum level of inclusion (in some cases) of all by-products (Chapter 5) . The results of in vivo digestibility by difference method of organic matter (OMd) and energy (GEd) of the liquid bakery by-product, brewers grains, hominy feed and high-moisture corn using a 50% of by-product inclusion into diet and at water-to-feed ratio 2.7:1 (water:dry matter), were not altered by the inclusion level of by-product into the diet. On the other hand, OMd and GEd of mayonnaise, almond meal, cocoa meal and kiwi was studied by regression method through four levels of inclusion (2, 4, 7 and 10%; and 4, 8, 12 and 16% for kiwi), being considered less conventional and riskier by-products. The evolution of ether extract digestibility suggested that the maximum level of inclusion of mayonnaise in the diet should not exceed 8.5%; or 6.1% for almond flour. The evolution of the digestibility of the other nutrients (i.e. Crude Fiber) recommended using cocoa meal and kiwi with caution. In the third study (Chapter 6), it was decided to seek alternative methods, less costly and laborious to than using live animals, and to perform prediction equations for organic matter and energy digestibility and energy content, digestible energy and metabolizable energy of agro-industrial by-products assessed in Chapter 5. Finally, in the last study (Chapter 7), it was evaluated in animals of different ages a wide range of dilution ratios (0:1, dry feed, and 0.6:1, 1.5:1, 2.1:1, 2.7:1 and 3.5:1) to determine those that optimize the digestibility of the ration and, to a lesser extent, performance results. It was shown that the lower dilutions (ratio 1.83:1, water:feed) are more appropriate for young animals and higher ratios (ratio 2.7:1) for fattening pigs

Effects of the feed : Water mixing proportion on diet digestibility of growing pigs

Funding: This research was funded by Spanish Ministry of Science and Innovation (CDTI project IDI-20110003), and TEM 2010 research grant form "Comissionat per a Universitats I Recerca del Departament d'Innovació, Universitats I empresa form Generalitat de Catalunya (AGAUR).The effect of different water-to-feed ratios on apparent total tract digestibility of energy and nutrients were evaluated in growing-finishing pigs. In trial 1 (26 d), 16 female pigs (46.7 ± 1.98 kg of body weight, BW) were individually assigned to four treatments (n = 4). In trial 1, pigs were fed a control diet in dry form (CON) and in blend form with water-to-feed ratios of 0.6:1, 2.1:1 and 2.7:1. In trial 2 (26 d), rearranged animals (65.4 ± 3.14 kg of BW) were assigned a control diet in dry form (CON) and ratios of 1.35:1, 2.7:1 and 3.5:1. In trial 1, pigs fed on ratios of 2.1:1 and 2.7:1 had a higher organic matter digestibility (OMd) and gross energy digestibility (GEd) than CON. In trial 2, pigs fed on ratios of 1.35:1, 2.7:1, and 3.5:1 had a higher OMd and GEd than CON. Quadratic regressions showed the maximum dilution rate to reach higher digestibility coefficients at 1.83:1 and at 2.7:1 for trials 1 and 2, respectively. During trial 1, pigs on the 0.6:1 dilution rate had higher weight gain than those on CON. The water-to-feed ratio that optimized OM and GE digestibility may increase with the age of the pigs