The aim of this study was to identify the potential target sites for the action of melatonin in sheep and to relate the findings to the photoperiodic control of reproductive activity in the female. It has been proposed that melatonin may have a direct luteotrophic role in several species, therefore the first experiment in this thesis was designed to investigate if melatonin acts directly on the ovine ovary to enhance progesterone production. The oral administration of 3mg melatonin, daily at 1500h, to anoestrous Blackface ewes advanced the onset of oestrous cyclicity and was associated with an increase in ovulation rate, at the first overt oestrous, compared to naturally ovulating control ewes. Peripheral prolactin concentrations were significantly suppressed within 7 days of the start of melatonin treatment. The concentration of progesterone was determined in samples collected directly from the utero-ovarian vein, and compared to the pulsatile pattern of luteinizing hormone (LH) secretion determined from samples collected from the jugular vein. The pattern of progesterone secretion in the utero-ovarian vein was episodic. The majority of progesterone pulses occurred independently of the pulsatile pattern of LH secretion, although each pulse of LH was followed by an increase in progesterone concentration. During the luteal phase of the first overt oestrous cycle, the pulsatile pattern of LH secretion and the progesterone concentrations in the utero-ovarian venous plasma were similar for both melatonin-treated and naturally ovulating control ewes. This suggests that melatonin does not have a direct luteotrophic action on the ovine ovary. The experiment described in Chapter 6 was designed to investigate if the ovine foetus is sensitive to photoperiodic information while in utero and also to assess the effect of prenatal photoperiod experience on the endocrine status and timing of puberty of ewe lambs. Three groups of female lambs were studied. Groups A and B were raised on a common postnatal photoperiod consisting of a 10 week block of long days (18L:6D) from birth followed by short days (6L:18D) until the end of the experiment at 38 weeks of age. These two groups of lambs differed only in the photoperiod experienced by their mothers during gestation; those in Group A were exposed to short days and those in Group B were exposed to long days from day 25 of gestation to parturition. Lambs in Group C experienced long days prenatally and short days from birth until the end of the experiment. Peripheral prolactin concentrations of lambs on the day of birth were dependent on the photoperiod to which their mothers were exposed during gestation. For the first 10 weeks after birth plasma prolactin profiles of the lambs raised under long days (Groups A and B) were influenced by their prenatal photoperiodic experience. The number of female lambs which exhibited puberty following a decrease in day length from 18L:6D to 6D:18L at 10 weeks of age was increased by maintaining their mothers on long days as opposed to short days during gestation. Puberty was delayed in the majority of female lambs which were exposed to long days in utero followed by short days from birth (Group C). The results suggest that lambs are sensitive to photoperiodic information prior to birth and that female lambs must be exposed to a minimum number of long days prior to a decrease in daylength to time the onset of puberty.

Supplements of a high quality dried grass, urea and molasses, and sodium hydroxide (NaOH) treatment were used to improve the intake and dry matter digestibility (DMD) of straw. Grass depressed straw intake by lambs significantly but increased that by steers non-significantly. Grass provided extra crude protein and motabolisable energy to meet maintenance requirements, and promoted liveweight gain at high levels of supplementation. Urea increased straw intake by lambs significantly, and increased intake in steers when it was contained in the grass supplement rather than the straw. There was no interaction between urea and grass on straw intake. Molasses depressed intake and DMD by lambs of straw supplemented with urea, but slightly increased straw intake in steers. There was no interaction between grass and molasses. NaOH-treatment increased straw intake and DMD significantly. Urea improved the intake of NaOH-treated straw significantly but had no significant effect on DMD. NaOH-treated straw plus-urea promoted a similar intake to straw treated with urea alone, but DMD was significantly better for the former. Maximal straw intake by steers occurred when the diet contained 4.0-5.2g crude protein per MJ gross energy. This was interpreted as a suitable ratio for optimum cellulolysis.

Se diseñaron 2 exp. con ovejas Lacaune (LC) y Manchega (MN), para comparar la ingestión de MS (MSI), la digestibilidad, la cinética de tránsito y el contenido digestivo, con el fin de explicar las posibles diferencias de ingestión. En el exp. 1, 10 ovejas MN y 10 LC gestantes, se estabularon durante las últimas 10 semanas de gestación. La MSI y MS digestible fueron superiores en las ovejas LC que en las MN. La raza no afectó a la digestibilidad, ni a la cinética de tránsito ni al contenido del tracto digestivo. Los cambios de peso vivo (PV) y condición corporal fueron similares. Por el contrario, los corderos LC tendieron a pesar menos que los MN, lo que sugiere diferencias genéticas entre razas en la utilización de la energía. La mayor ingestión observada en las LC podría estar relacionada con la mayor demanda energética para el desarrollo de la glándula mamaria. En el exp. 2, 16 ovejas MN y 16 LC se estabularon las 12 primeras semanas de lactación. La producción de leche, el contenido de grasa y proteína, así como la MSI y MS digestible fueron superiores en las ovejas LC que en las MN. Al avanzar la lactación la MSI se mantuvo constante en las ovejas LC, mientras que en las MN disminuyó. A lo largo de este periodo las LC perdieron 0.5 kg de PV mientras que las MN ganaron 4.4 kg. La raza no afectó ni la digestibilidad, ni la cinética de tránsito. El contenido total del tracto digestivo fue superior en las LC que en las MN. Los resultados sugieren que el esquema de selección de la raza LC, ha incrementado la producción de leche junto con la ingestión voluntaria, estando ésta última asociada a un incremento de la capacidad ruminal. La mayor producción de leche de las LC no pueden atribuirse únicamente a la mayor MSI y otros factores son necesarios para soportar esta mayor producción. Finalmente, se compararon 6 modelos matemáticos con el fin de seleccionar el que mejor describía el tiempo de retención de dos marcadores, Cr2O3 y Co-EDTA. Se utilizaron los datos de los experimentos 1 y 2. Las curvas de excreción de cromo y cobalto se ajustaron a un modelo compartimental (M1), dos modelos bicompartimentales tiempo independientes con tiempos de retención distribuidos exponencialmente (M2 y M3), y tres modelos bicompartimentales tiempo dependientes con órdenes crecientes de gamma dependencia (M4, M5 y M6). Los modelos M1, M5 y M6 fueron los mejores ajustes para describir la cinética de tránsito digestivo. Con el fin de averiguar si las estimaciones obtenidas utilizando marcadores son una buena expresión de los parámetros reales, 8 ovejas se sacrificaron en la semana 5 y otras 8 en la semana 12 de lactación. Antes del sacrificio, se les administraron 2 marcadores, Cr2O3 y Co-EDTA, para estimar los ritmos de paso en los compartimentos digestivos. Los ritmos de paso estimados con las curvas de excreción fecal de Cr2O3 no representaron la cinética digestiva del marcador obtenida con los datos de sacrificio, aunque la predicción mejoró cuando se utilizó el Co-EDTA. / Two experiments were carried out with pregnant and lactating dairy ewes, to compare dry matter intake (DMI), and total tract apparent digestibility, digesta kinetics and digestive tract content between Lacaune (LC) and Manchega (MN) sheep, to explain possible differences between both breeds in voluntary feed intake. In experiment 1, 10 MN and 10 LC single-bearing pregnant ewes, were permanently housed for the last 10 weeks of pregnancy. DMI and digestible DMI were higher in LC than in MN sheep. Breed did not affect total tract apparent digestibility, digesta kinetics or digestive content. Changes in body weight and body condition score were similar between breeds. In contrast, LC lambs tended to weigh less than MN lambs, suggesting genetic differences in the energy utilization between breeds in late pregnancy. Higher DMI observed in LC sheep could be related to higher energy demand for mammary development. In experiment 2, 16 MN and 16 LC lactating multiparous ewes, were permanently housed during the first 12 weeks of lactation. Milk, fat and protein yield as well as DMI and digestible DMI in LC ewes was higher than in MN ewes. DMI was constant in LC sheep with advancing lactation, while in MN sheep decreased. Throughout this period LC ewes lost 0.5 kg of body weight while MN gained 4.4 kg. Breed did not affect either apparent digestibility or digesta kinetics. The total tract digestive content was higher in LC than in MN sheep, particularly due to the reticulo-rumen. Results suggest that the scheme of selection in LC dairy sheep has increased milk yield together with voluntary feed intake, the latter being associated with an increase in the rumen fill capacity. Finally, the aim of the third study was to take a mathematical approach to select the best modelling method to estimate the outflow rates from external marker excretion curves in dairy sheep. Data from previous experiments were used as a source of marker excretion curves. Six mathematical models were compared. Faecal chromium and cobalt concentration curves were fitted with a multicompartmental model (M1), 2 two-compartment age-independent models with exponential distributed residences times (M2 and M3), and 3 two-compartment models with increasing order of gamma age dependency (M4, M5 and M6). The models M1, M5 and M6 proved to be the best fits for describing digesta kinetics in pregnant and lactating ewes. To ascertain whether the estimates obtained through the markers are a good expression of the real parameters, 8 lactating ewes were slaughtered at week 5 and 8 more at week 12 of lactation, Prior to slaughtering, two external markers were administered in order to estimate rates of passage of the reticulo-rumen and large intestine. Outflow rates estimated from faecal chromium excretion did not represent marker kinetics in the gut compartments obtained from slaughter data, but the prediction improved when the marker was Co-EDTA.

El objetivo principal de esta memoria de tesis es evaluar la interacción entre ácidos grasos poliinsaturados y vitamina E dietéticos sobre la deposición corporal de ácidos grasos y -tocoferol en pollos broiler. Se diseñaron dos experimentos que basados en niveles crecientes de acetato de -tocoferol (0, 100, 200 y 400 mg/kg) y ácidos grasos poliinsaturados en los piensos. En la primera prueba, el gradiente de poliinsaturación se obtuvo mezclando una grasa saturada (sebo) con una mezcla de aceites insaturados (aceites de linaza y pescado), manteniendo el nivel de inclusión de la grasa constante (9%). En la segunda prueba, el gradiente se creó incrementando el nivel de inclusión de la grasa añadida (2, 4, 6 y 8%), utilizando aceites de linaza y pescado. Se realizaron 2 balances para determinar la energía metabolizable aparente, la absorción aparente de la materia orgánica, la grasa bruta, los ácidos grasos y el -tocoferol, y el porcentaje de hidrólisis del acetato de -tocoferol. Al final de cada estudio (44 y 40 días de edad), la mitad de los animales fueron sacrificados mediante inyección letal y la otra mitad en un matadero. Los primeros se conservaron enteros y los últimos se despiezaron, obteniéndose la grasa abdominal y el hígado. Se cuantificaron los ácidos grasos y el -tocoferol en el cuerpo entero. -tocoferol también se determinó en el hígado. También se analizó la composición química y el contenido en energía bruta del pollo entero. La poliinsaturación dietética manteniendo el nivel de grasa constante (prueba 1) tuvo efecto sobre la energía metabolizable aparente de los piensos. Los animales que ingirieron el pienso más saturado tuvieron una menor absorción aparente de la materia orgánica, disminuyendo así la energía metabolizable aparente de este pienso. A pesar de esto, los animales alimentados con 9% de sebo tuvieron un mayor contenido en grasa y energía en el cuerpo. Por el contrario, incrementar la poliinsaturación dietética mediante el aumento del nivel de inclusión de grasa (prueba 2) no tuvo ningún efecto sobre la composición química ni el contenido en energía del pollo. El aumento de la ingestión de ácidos grasos poliinsaturados resultó en incrementos lineales de su concentración en los pollos en ambos experimentos. La contribución de la síntesis endógena a la concentración corporal de ácidos grasos saturados y monoinsaturados se estimó utilizando los datos combinados de las dos pruebas. Ésta varia entre 17.7% (10% de grasa en el pienso) a 35.3% (0% de grasa) en el caso de los ácidos grasos saturados; y entre un 7.0% y 52.7% en el caso de los monoinsaturados. La inclusión de acetato de -tocoferol no tuvo efectos marcados sobre el contenido de ácidos grasos del pollo. Los valores de absorción aparente del -tocoferol variaron entre 11 y 50%, con un valor medio de 42.1% bajo nuestras condiciones experimentales. No hubo diferencias al comparar las dos edades (20 y 39 días de edad). La inclusión de sebo al 9% en el pienso afectó negativamente a la absorción aparente del -tocoferol y el porcentaje de hidrólisis de acetato de -tocoferol. Por otra parte, incrementos en el nivel de inclusión de la grasa añadida rica en ácidos grasos poliinsaturados no tuvieron efecto sobre estos parámetros. Niveles elevados de ácidos grasos poliinsaturados en la dieta no afectaron la absorción aparente de -tocoferol, pero redujeron la concentración de -tocoferol libre en heces, sugiriéndose un gasto en el tracto gastrointestinal previa absorción. El depósito de -tocoferol en el hígado fue menor en los animales alimentados con los piensos más insaturados comparados con los animales alimentados con el pienso saturado (prueba 1) y a los animales alimentados con el pienso bajo en grasa. / The main objective of this PhD dissertation is to evaluate the interaction between dietary poliunsaturated fatty acids and vitamin E on body deposition of fatty acids and -tocopherol in broiler chickens. Two experiments were designed based on -tocopheryl acetate supplementation (0, 100, 200 and 400 mg/kg) and a gradient of dietary poliunsaturation. In trial 1, this gradient was achieved blending tallow (rich in saturated fatty acids) with linseed and fish oil (unsaturated oils), keeping added fat constant (9%). In trial 2, the gradient was made increasing the inclusion level of dietary fat (2, 4, 6 and 8%), a blend of linseed and fish oil. Two balance studies were made in order to measure apparent metabolizable energy, apparent absorption of organic matter, crude fat, fatty acids and -tocopherol, and also -tocopheryl acetate percentage of hydrolysis. At the end of each trial (40 and 44 days of age), half of the animals were killed by lethal injection and the other half were killed in a slaughterhouse. The former were kept whole and the latter were quartered and the liver and absdominal fat pad were obtained. Fatty acids and -tocopherol were quantified in the whole body, and -tocopherol was also measured in the liver. Aslo, the chemical composition (Weende) and energy content of the whole body was analyzed. Dietary poliunsaturation, keeping added fat constant, had effect upon apparent metabolizable energy content of the diets. The animals fed the more saturated diet had lower apparent absorption of organic matter, resulting in a lower apparent metabolizable energy of this diet. However, the animals fed this saturated diet had higher energy and fat content in the whole body. On the other hand, increasing dietary poliunsaturation by means of increasing added fat inclusion level had no effect whatsoever upon chemical and energy content of the chickens. The increase in polyunsaturated fatty acids intake resulted in a linear increase in their body deposition in both trials. The contribution of endogenous synthesis to fatty acid composition of the body was estimated using the combined data of both trials. This contribution varies between 17.7% (10% of dietary fat) and 35.3% (0% dietary fat) for the saturated fatty acids; and between 7.0% and 52.7% for the monounsaturated ones. Vitamin E inclusion had no marked effects upon fatty acid content in the whole body. Apparent absorption coefficients for vitamin E varied between 10 and 50%, with an average value of 42.1% under our experimental conditions. There were no differences in this variable when comparing between the two ages (20 and 39 days of age). The inclusion of 9% of tallow affected negatively -tocopherol apparent absorption and -tocopheryl acetate % of hydrolysis. On the other hand, increases in added fat inclusion level had no effect on these parameters. High dietary poliunsaturation levels did not affect vitamin E apparent absorption but resulted in lower free -tocopherol excretion, suggesting a gastrointestinal waste by lipid oxidation previous to its absorption. -tocopherol deposition in the liver was lower in the animals fed the more unsaturated diets compared to the ones fed the saturated (trial 1) or the low-fat ones (trial 2).

Es va realitzar un únic experiment amb una mostra inicial de 103 truges Landrace x Large White de genètica PIC, de entre 0 i 4 parts amb l'objectiu de determinar el efectes de l'alimentació de la truja gestant durant la part mitja de la gestació en el desenvolupament de les fibres musculars de la progènie y els rendiments productius de les mares. Aquestes truges van ser distribuïdes en dos grups experimentals, control (C, n = 49) i suplementat (S, n = 54). Les truges control van ser alimentades seguint el patró normal d'alimentació de la granja durant el període de gestació (2.5-3.0 kg/dia; 12.1 MJ EM/kg i 0.62 % de lisina de mitja). Les truges suplementades van rebre un suplement de +50% i +75% del mateix pinso, en el cas de truges nulípares i multípares respectivament, entre els dies 45 i 85 de gestació. Aquest mateix tractament es va aplicar durant tres cicles consecutius. Els garrins mascles (castrats) provinents dels cicles 1 i 3 es van dividir al naixement en dos grups (Control, C i Suplementat, S) segons el tractament nutricional rebut per les seves mares. Els rendiments productius d'aquests animals es van avaluar en les fases de transició (n = 958) i engreix (n = 636). Al sacrifici, diversos paràmetres de qualitat de la canal i de la carn (n=90) així com diferents característiques de les fibres musculars de la progènie (nombre total de fibres musculars, àrea mitja i tipus de fibres, n=70) varen ser estudiats. Els garrins nascuts de mares suplementades presentaren majors guanys de pes diaris i consums mitjos en el cicle 1 (P<0.05) i una superior eficiència de conversió en el cicle 3 (P<0.05) durant el període de transició, però aquestes diferències van desaparèixer a la fase d'engreix. Respecte als paràmetres de qualitat de la carn, els animals S presentaren un pH més elevat a les 24 hores després del sacrifici (pH24) en el múscul semimembranosus i una menor lluminositat (L*) mesurada en una secció transversal del múscul longissimus thoracis, en relació amb els porcs del grup C, de forma consistent en els cicles 1 i 3 (P<0.05). El tractament experimental també va provocar diferències en les característiques histològiques de les fibres musculars. Els garrins nascuts de mares suplementades van desenvolupar un menor nombre de fibres musculars però de major àrea mitja en ambdós cicles estudiats (P < 0.15), mentre que la relació entre el nombre de fibres secundàries i el nombre de fibres primàries es va mantenir constant entre tractaments. En l'animal adult, els porcs S presentaren un menor nombre de fibres tipus IIB (P<0.05) però amb una major àrea transversal (P<0.10) en relació als porcs C. Pel que fa a les truges, el pes viu (BW) i els nivells de reserves corporals [Gruix de greix dorsal (BF), profunditat de llom (LD) i nota de condició corporal (BCS)] van ser mesurats en diferents moments del cicle reproductiu en els tres cicles estudiats. La productivitat al moment del part i als 18 dies de lactació així com la longitud del interval deslletament-cobrició (WEI) varen ser enregistrats. Les truges que començaren l'experiment com a truges nulípares van ser capaces d'acumular teixit magre però també teixit lipídic en resposta a l'augment del nivell d'alimentació en gestació durant tres cicles consecutius, mentre que les truges multípares (>2 parts) dipositaren majoritàriament teixit gras. En termes productius, aquesta estratègia d'alimentació va resultar en un increment en el pes mig al naixement dels garrins nascuts de truges primípares en el cicle 3 (+300 g/garrí en el grup de truges S) però va tenir efectes negatius en quant a nombre de garrins deslletats en el grup de truges S. No es van trobar diferències en entre tractaments experimentals en el WEI. Un estudi exploratori de les dades del cicle 1 va demostrar que els nivells de reserves corporals al part (BW, BF i LD) estaven associats positivament amb les seves respectives pèrdues durant el període de lactació, però també positivament amb els seus nivells de reserves al deslletament. A més a més, es va trobar una associació dèbil però positiva entre la pèrdua de BF en lactació i el WEI (r=0.25, P<0.05). En aquest estudi, les truges primípares donaren lloc a garrins de menor pes al naixement i al deslletament i a WEIs més llargs en comparació amb aquells de les truges multípares (P<0.05). Finalment, la nota de condició corporal visual (BCS) va presentar una associació moderada (r=0.54-0.49, P<0.01) amb el nivell de reserves corporals de la truja mesurats mitjançant ultrasons (BF i LD). En resum, un increment del nivell d'alimentació en la part central de la gestació va provocar un efecte en les característiques de les fibres musculars i la qualitat de la carn de la progènie, sense afectar als rendiments productius. A més a més, aquesta estratègia d'alimentació va presentar efectes beneficiosos en el pes dels garrins al naixement en les truges de primer part, però no en truges multípares. / In order to study the effects of pregnant sow nutrition on progeny muscle fibres development and sow performance, a study involving an initial pool of 103 Landrace x Large White PIC sows from 0 to 4 parities was designed. Sows were divided into two experimental groups, control (C, n=49) and supplemented (S, n=54). Control sows were fed according to the feeding strategy routinely followed on the farm throughout gestation (2.5 to 3.0 kg/day; 12.1 MJ ME/kg and 0.62 %lysine). Supplemented sows were provided with an extra feed allowance of +50% and +75% of the same feed for both gilts and multiparous sows, respectively, from day 45 to day 85 of gestation. The same feeding strategy was applied over three consecutive reproductive cycles. Male (castrated) progeny from cycles 1 and 3 were assigned at birth to one of the two treatments (Control, C and Supplemented, S) according to the dietary treatment received by their mothers. Growth performance throughout the nursery (n=958) and growing-finishing periods (n=636) was evaluated. Additionally, carcass and meat quality traits (n=90) and muscle fibre characteristics (total number of muscle fibres, mean cross-sectional area and fibre types, n=70) were studied at slaughter. Pigs born from supplemented mothers showed higher daily weight gains and feed consumption rates in cycle 1 (P<0.05) and higher feed efficiencies in cycle 3 (P<0.05) during the nursery period, but these differences disappeared in the growing-finishing phase. Regarding meat quality, S pigs showed a higher ultimate pHs (pH24h) in the semimembranosus muscle and a lower lightness (L*) in the cross-section of longissimus thoracis muscle compared to the C group of pigs, consistently in cycles 1 and 3 (P<0.05). Differences in muscle fibre characteristics were also found between treatment groups. The S pigs showed a lower number of muscle fibres with higher mean areas in both cycles (P<0.15), and an invariable estimated secondary to primary fibres ratio. In the adult animal, S pigs showed a lower number of type IIB fibres (P<0.05), but with larger sizes (P<0.10, cross-sectional area) compared to C pigs. Regarding sows, body weight (BW) and body reserves [backfat (BF), loin depth (LD) and body condition score (BCS)] were measured at different times throughout the reproductive cycle over the three cycles studied. Productive performance at farrowing and on day 18 of lactation and weaning to oestrus interval (WEI) were also recorded. Sows which started the study in their first parity accumulated both, lean and fat tissue in response to the increased gestation feed allowance over the three cycles, while multiparous sows (>2 parities) mainly accreted fat tissue. Additionally, the extra feeding enhanced primiparous piglet weight at birth in cycle 3 (+300 g/pig in the S group of sows) but impaired lactation performance in terms of weaned pigs in the S group of sows. No differences were found between treatments regarding WEI. An exploratory study in the sows of cycle 1 revealed that body reserves levels at farrowing (BW, BF and LD) were positively associated with their respective losses during the lactation period, but also with their levels at weaning. Additionally, BF losses during lactation showed a low but positive association with WEI (r = 0.25, P<0.05). Also, in this study, first parity sows showed lower piglet weights at farrowing and at weaning and larger WEIs compared to multiparous sows (P<0.05). Finally, the visual body condition score (BCS) appeared to be moderately correlated (r=0.54-0.49, P<0.01) with sow body reserves measured by ultrasounds (BF and LD). Overall, an extra feed allowance during mid-pregnancy affected progeny muscle fibre characteristics and meat quality traits without leading to differences in growth performance. Moreover, this feeding strategy had beneficial effects on piglet birth weight in first parity sows, but not in multiparous sows.

Las paredes celulares de levadura (PCL) de S. cerevisiae vienen siendo utilizadas en avicultura por hace más de una década, algunas de las finalidades de esta práctica son las de mejorar la productividad y salud del ave. Los polisacáridos tipo beta-glucanos y mánanos presentes en la PCL, pueden ejercer efectos en el sistema inmune del pollo y exclusión de patógenos a escala digestiva. No obstante, debido a que la industria de la fermentación genera gran diversidad levaduras y PCL de diferente origen y características, el estudio acerca del mejor conocimiento y definición de estos nuevos aditivos puede ser clave para optimizar su utilización alimentación animal. En la presente tesis, se realizaron 6 experimentos (Exp.) con pollos de engorde machos (Ross 308) con el objetivo de evaluar las respuestas en la productividad y la salud de las aves al proporcionarles dietas elaboradas con maíz o trigo-cebada-centeno (TCC), con diferentes levaduras activas de S. cerevisiae (pecuario, panadería y "killer" vinícola) y sus componentes: 2 distintas paredes celulares de levadura (PCL), extractos, beta-glucanos (BG) y manano-proteínas (MP), en ninguno de los experimentos se emplearon aditivos en el alimento de tipo antibióticos, coccidiostatos o enzimas. En los Exp. 1 y 2, se observo que las características propias de las distintas levaduras de S. cerevisiae y de sus componentes (extractos y PCL), así como el tipo de dieta empleada (TCC o maíz), adquieren importantes implicaciones en las respuestas que pueden ejercer en el animal. Las PCL-2 derivada de la producción de extractos de levadura, y con mayor contenido de MP y BG, adicionadas (500 mg/kg) en dietas con TCC (Exp. 1) o maíz (Exp. 2), fueron capaces de mejorar el peso vivo y el índice de conversión del ave de forma similar al empleo de avilamicina (0.01 mg/kg alimento). Los distintos aditivos derivados de S. cerevisiae no afectaron claramente variables ileales como la viscosidad, absorción de nutrientes y recuentos bacterianos. En el Exp. 2, se encontró que el empleo de la PCL-2, favoreció el desarrollo de la mucosa digestiva del ave al incrementar la altura, el grosor de la mucina y el número de células caliciformes de las vellosidades del yeyuno (dietas con TCC o maíz). Además, la utilización en la dieta (TCC) de MP y BG purificados de PCL, resultó en mayor altura de las vellosidades de la mucosa del yeyuno (Exp. 3). Por otra parte, el empleo de MP+BG en concentraciones parecidas a las presentes en la PCL-2, representó efectos similares en el peso relativo del timo respecto a la PCL-2 (Exp. 4). La utilización de la PCL-2, MP, BG, o MP+BG en la dieta de pollos, no mostró diferencias claras en la productividad del ave en favor de alguno de los aditivos (Exp.4 y 5). En el Exp. 6, se observo que las PCL-2, incrementaron la reacción de hipersensibilidad cutánea tardía o determinación indirecta de la inmunidad celular en los pollos. Este efecto inmunomodulador de las PCL, pudo brindar beneficios en las pollos sometidos a estrés inflamatorio por la inoculación con lipopolisacárido (LPS) de E. coli, los cuales fueron traducidos en una mejor eficiencia alimenticia y % de peso relativo de la bolsa de Fabricio similares a los observados en pollos control sin estrés inmunitario (no desafiados con LPS). Los resultados de estos experimentos mostraron que las PCL adicionadas a dietas de pollos de engorde pudieron mejorar su eficiencia productiva, parte del mecanismo podría estar relacionado con favorecer el desarrollo de la mucosa digestiva y mantener un mejor estado de inmunocompentencia del ave, situación que puede tener beneficios en ambientes con mayor presencia desafíos microbianos. / The yeast cell walls (YCW) from S. cerevisiae have been used in poultry feeding for more than one decade; some of the purposes of this practice are to improve the chicken productivity and health. The polysaccharides such as beta-glucans and mannans presents in the YCW can exert effects in the immune system of chicken and also pathogen exclusion at digestive scale. However, the fermentation industry generates great diversity of active yeast and YCW from different origin and characteristics thus, the study about the correct definition and origin of these new additives can be necessary to optimize its use animal feeding. In the present thesis, there were carried out six experiments (Exp.) with male broiler chickens (Ross 308), with the objective of evaluating the effects of dietary supplementation of active yeast from S. cerevisiae (pecuary, bakery and "killer" winery) and their components: 2 YCW, extract, beta-glucans (BG) and manno-proteins (MP), to maize and wheat+barley+rye based diets on productivity and health of broiler chickens. In all experimental diets there were not used additives such as antibiotic, coccidiostates and feed enzymes. In the Exp. 1 and 2, It was observed that the own characteristics of different yeast (S. cerevisiae) and its components (extracts and YCW) as well as the type of diet used (TCC or maize) in these experiments, were important in the productive and digestive responses evaluated in the broiler chickens. The YCW-2 from the industrial production of yeast extracts, and with greater content of MP and BG, added (500 mg/kg) to WBR (Exp. 1) and maize (Exp. 2) based diets, improved the live weight and feed conversion ratio of broiler chickens in a similar magnitude to that obtained with dietary avilamycin (0.01 mg/kg feed). The different dietary additives derived from S. cerevisiae did not affect clearly variables at ileal level such as viscosity, bacterial counts and nutrients absorption. In the Exp. 2, the use of YCW-2 in WBR and maize based diets, improved the mucosa development of chickens by increasing the height, the mucin mucus thickness and the number of goblets cells of villous (jejune mucosa). In addition, in WBR based diet, dietary MP and BG purified from YCW, increased the villous height of jejune mucosa (Exp. 3). On the other hand, dietary MP+BG in a similar concentration respect to that present in YCW-2, represented similar effects in the percentage relative thymus weight respect to the dietary YCW-2 use (Exp. 4). The dietary use of YCW-2, MP, BG, or MP+BG in broiler diets did not show clearly differences in the productivity of chickens in favour of some of them (Exp.4 and 5). In the Exp. 6, dietary YCW-2 increased the delayed cutaneous hypersensitivity response or indirect determination of cellular immune response in chickens. This immunomoduladory effect of dietary YCW-2, could bring some benefits to chickens with immunitary stress (challenge with lipopolysaccharide or E. coli-LPS), because chickens fed YCW-2 and challenge with LPS showed similar feed efficiency and percentage relative bursa of Fabricius weighs than those not challenge chickens. The results of these experiments showed that the dietary supplementation with YCW-2 to broiler chickens diets can improve the animal productive performance; part of the mode of acting of dietary YCW could involve favouring intestinal health and maintaining a better state of immune-competence in the chickens. These positive effects can bring some benefits to chickens when raised under stress conditions or in environments causing great microbial challenges.

Se utilizaron 79 ovejas Manchega y 56 ovejas Lacaune en 4 experimentos para estudiar los efectos del intervalo entre ordeños y de la supresión de ordeños sobre la producción, la composición de la leche, los compartimentos de la ubre y la permeabilidad de las uniones estancas. En el Exp. 1 y 2, 12 Manchegas y 12 Lacaunes fueron ordeñadas a diferentes intervalos entre ordeños (4, 8, 12, 16, 20 y 24 h), a mitad de lactación. La leche total y cisternal aumentaron linealmente hasta las 24 h, mientras que la alveolar lo hizo hasta las 16 h en Manchega y 20 h en Lacaune, mostrándose el papel relevante de la cisterna mamaria para acumular leche y favorecer el aumento de la producción. Las Lacaune siempre presentaron mayores volúmenes y porcentajes cisternales que las Manchega. El área cisternal aumentó hasta las 20 h en Manchega y 16 h en Lacaune, debido a la limitada profundidad de la sonda. A las 8 h, se obtuvieron las mejores correlaciones entre el área y la leche cisternal (Manchega: r = 0.70; Lacaune, r = 0.56). La grasa disminuyó en la leche total y cisternal al incrementarse el intervalo entre ordeños, y aumentó en la alveolar hasta las 12 h en Manchega y las 20 h en Lacaune. La proteína láctea sólo aumentó en la leche alveolar al hacerlo el intervalo. El contenido en lactosa no varió en las Lacaune pero disminuyó en las Manchega a las 24 h. La lactosa plasmática aumentó marcadamente tras 20 h de acumulación de leche en la ubre, por tanto, las uniones estancas se abrieron en ambas razas, aunque en mayor medida en Manchega. En el Exp. 3, 27 Manchegas y 26 Lacaune se ordeñaron 1 (1X) o 2 veces al día (2X) al inicio (sem. 6-14) o mitad (sem. 14-22) de lactación. 1X al inicio de lactación, redujo un 37% la producción en Manchega pero menos de un 11% en Lacaune. Las ovejas con cisternas pequeñas mostraron pérdidas superiores. A mitad de lactación, 1X no produjo pérdidas productivas. La composición y el RCS no se afectaron negativamente por 1X, pero la permeabilidad de las uniones estancas aumentó al pasar de 2X a 1X, especialmente al inicio de la lactación y en las Manchega. En el Exp. 4, se utilizaron 40 Manchegas y 18 Lacaune para estudiar la respuesta productiva a la supresión de 2 ordeños semanales (12X) con respecto a la no supresión de ordeños (14X), al inicio (sem. 7-15) y a mitad de lactación (sem. 15-22). Al inicio de la lactación, 12X tendió a reducir un 16% la producción de leche en Manchega, pero no la afectó a partir de mitad de lactación. En las Lacaune, 12X no afectó a la producción de leche. La supresión de ordeños no afectó negativamente la composición ni los RCS de la leche. El día de la supresión, la producción, el contenido en grasa y en lactosa de la leche disminuyeron en ambas razas, siendo más marcada la pérdida productiva al inicio que a mitad de lactación. Al recuperar la rutina normal de ordeño, la producción de leche aumentó marcadamente, tanto más cuanto mayor fue el tamaño cisternal. El porcentaje graso mejoró desde el segundo día de supresión, recuperando los valores de referencia 48 horas después de la última supresión. La proteína no varió a lo largo de la semana y los RCS de la leche no se vieron afectados negativamente por las supresiones. Las uniones estancas se debilitaron en ambas razas, pero el epitelio mamario pareció adaptarse a las supresiones al aplicarse de forma sucesiva. / Seventy-nine Manchega and 56 Lacaune dairy ewes were used in 4 experiments to study the effects of milking intervals and milking omissions on lactational performance, udder compartments and TJ leakiness. In Exp. 1 and 2, 12 Manchega and 12 Lacaune were milked at different milking intervals (4-, 8-, 12-, 16-, 20-, and 24-h) in a 2-wk experiment performed in mid-lactation. Total and cisternal milk increased linearly for up to 24-h, whereas alveolar milk increased until reaching a plateau at 16-h in Manchega and 20-h in Lacaune ewes, demonstrating the ability of the cistern to dilate as a result of milk transfer from the alveolar to the cisternal compartment. Lacaune ewes accumulated greater cisternal volumes and showed greater cisternal percentages than Manchega ewes for all the milking intervals. Cisternal area measured by ultrasonography increased with milking interval until 20 h in Manchega and 16 h in Lacaune ewes, being conditioned by probe depth capability. The greatest correlation between cisternal area and cisternal milk was observed at 8-h milking interval (Manchega, r = 0.70; Lacaune, r = 0.56). Milking interval affected markedly milk fat content, which decreased in total and cisternal milk from 4- to 24-h in both breeds, but increased in alveolar milk (until 12 h in Manchega; and 20 h in Lacaune). Total and cisternal milk protein content did not vary, but protein content increased in alveolar milk with milking interval. Lactose milk content was stable in Lacaune and decreased at 24 h in Manchega ewes. Plasma lactose increased dramatically after 20 h of milk accumulation, indicating an enhanced permeability of mammary TJ in both breeds, despite being more pronounced in Manchega than in Lacaune ewes. In Exp. 3, 27 Manchega and 26 Lacaune were milked 1X or 2X in early- and mid-lactation. Once-daily milking, when performed in early-lactation, reduced milk yield by 37% in Manchega and by less than 11% in Lacaune, those with small mammary cisterns being more affected. Milk yield was not affected by 1X when started in mid-lactation in either breeds. No negative effects on milk composition and SCC were observed. TJ permeability increased after switching from 2X to 1X, especially in early lactation and in Manchega ewes. In Exp. 4, 40 Manchega and 18 Lacaune were used to study the response to omitting 2 milkings weekly (12X) in early- (wk 7 to 15) and mid- lactation (wk 15 to 22) comparing to milking twice-daily every day (14X). Omitting 2 milkings weekly tended to reduce milk yield by 16% in Manchega ewes when applied in early-lactation, but no effects were observed in mid-lactation. Milk yield did not decrease as a result of 12X in Lacaune ewes, either in early- or in mid-lactation. Milk composition and SCC were not negatively affected by milking omissions throughout lactation. Milking omission decreased milk yield, milk fat and lactose content on the 1st omission day of the week in both breed, losses being more noticeable in early- than in mid-lactation. A compensatory increase was noticed in milk yield after recovering the twice-daily milking routine, being greater in large- than in small-cisterned ewes. Milk fat content increased after the 1st milking omission, reestablishing reference values 48 h after the 2nd milking omission, and this should be taken into account for milk recording. Milk protein did not vary and SCC was not negatively affected by milking omissions. Milking omissions caused TJ leakiness in both breeds, but mammary epithelium adapted to extended milking intervals when applied successively.

L’objectiu d’aquesta tesi és avaluar i discutir l’aplicació pràctica, la validesa i la repetibilitat d’un sistema d’avaluació del benestar en granges comercials de porcs d’engreix. La capacitat d’aplicació, la sensibilitat, selectivitat, validesa contextual i repetibilitat al llarg del temps de les mesures basades en l'animal incloses al protocol Welfare Quality® es van avaluar mitjançant cinc estudis. A més a més, al llarg de la tesi es va considerar la utilització del protocol com a eina d’assessorament per resoldre problemes de benestar. En el primer estudi es presenta una anàlisi descriptiva de les mesures basades en l’animal incloses al protocol d’avaluació del benestar. En aquest treball es va avaluar tant l’aplicació pràctica del protocol en 30 granges intensives com la seva capacitat per discriminar-les entre sí. Tanmateix, el treball proposa una metodologia pràctica per identificar granges que presenten algun problema de benestar. Al segon i tercer estudi, es van avaluar un total de 11,647 porcs allotjats en 91 explotacions comercials provinents de tres sistemes intensius (convencional a França i Espanya, sobre palla a França, i Ibèric intensiu a Espanya) així com dos sistemes extensius (Ibèric en extensiu, Porc Negre Mallorquí) mitjançant el protocol Welfare Quality®. Tot dos estudis descriuen dades sobre la prevalença i distribució de diversos indicadors de benestar en una gran varietat d’explotacions amb la finalitat d’identificar una sèrie de factors causals. Els resultats corresponents als principis de bona alimentació i bon allotjament es presenten en el segon estudi mentre que els de salut es descriuen en el tercer. El quart estudi es centra en l’avaluació del benestar mitjançant mesures de comportament en porcs Ibèrics en condicions intensives i extensives. En aquest treball, el quart principi del Welfare Quality®, titulat “comportament adequat”, es va avaluar en 21 granges (11 extensives i 10 intensives), les quals allotjaven una totalitat de 25,856 porcs Ibèrics. Finalment, el cinquè estudi avalua, en una mostra de 15 granges intensives convencionals, la repetibilitat després d'un temps perllongat de les mesures basades en l’animal incloses en el protocol Welfare Quality®. Els resultats es van discutir des d’un punt de vista discriminatiu i avaluatiu. Com a comentari general, el protocol Welfare Quality® per porcs d’engreix es pot aplicar fàcilment en una gran varietat d’explotacions comercials. Tot i així, la durada total del protocol pot ser percebuda com a massa llarga per part d’alguns dels agents implicats (com ara ramaders, industria o empreses certificadores). La sensibilitat dels indicadors de salut és aparentment massa baixa. La interpretació d’alguns resultats en termes de benestar animal, especialment els de comportament, s’ha de realitzar amb molta cura sobretot quan es comparen explotacions provinents de sistemes de cria molt diversos. Una interpretació equivocada d’un resultat pot erròniament afavorir o perjudicar un ramader o un sistema. Finalment, el protocol Welfare Quality® pot tenir enfocaments diversos que poden ser pràctics i complementaris com a eina d’assessorament, tot i que es va dissenyar com una eina per auditar. / The objective of the present thesis is to evaluate and discuss the feasibility, validity and repeatability of a welfare assessment system for growing pigs on commercial farms. The feasibility, sensitivity, selectivity, contextual validity and repeatability over time of several animal-based measures of the Welfare Quality® (WQ®) protocol were evaluated in five studies. Furthermore, across the thesis, the use of the protocol as an advisory tool is considered. The first study presents a descriptive analysis of several animal-based measures of the welfare assessment protocol for pigs kept under intensive conventional conditions on 30 farms in Spain. It evaluates the feasibility of the protocol on intensive farms and its capacity to discriminate among intensive conventional farms. It also aims to propose a practical methodology to identify farms with a particular welfare problem. On the second and third studies, a total of 11,647 pigs housed on 91 commercial farms of three intensive systems (conventional in France and Spain, straw bedded in France, and Iberian intensive in Spain) as well as two extensive systems (Iberian extensive, Mallorcan Black pig) were assessed applying the overall WQ® protocol. Both studies yielded data about the prevalence and distribution of several welfare outcomes on a wide variety of commercial farms with the aim to identify possible causal factors. The results from the good feeding and housing principles are presented in the second study whereas those of health are given in the third study. The fourth study focused on the assessment of welfare through behavioural measures in Iberian pigs in intensive and extensive conditions. The fourth principle of the WQ® protocol, labelled “Appropriate behaviour”, was assessed on 21 farms (11 extensive and 10 intensive) housing a total of 25,856 Iberian pigs. Changes in occurrence of behaviour and qualitative measures were evaluated and discussed when comparing Iberian pigs either in intensive or extensive rearing conditions. Finally, the fifth study evaluated the test-retest repeatability over a long period of time of the mean prevalence of several measures from the WQ® protocol on a sample of 15 intensive conventional farms of growing pigs. The results were discussed from a discriminative approach and from an evaluative approach. As a general comment, the WQ® protocol for growing pigs is feasible in a wide range of commercial conditions even though the overall duration may be perceived as too long by stakeholders. The sensitivity of health indicators appears to be low. Interpretation of several outcomes, especially behavioural ones, in terms of animal welfare, must be cautious, especially when comparing farm units from diverse rearing systems. An erroneous interpretation of an outcome can wrongly favour or prejudice a farmer. Several approaches of the WQ® protocol can be practical and complementary to be used for advisory purposes.

Das neue Tieridentifikationssystem Agro SAW IDENT wurde gemeinsam mit Industriepartnern entwickelt. Den Kern bilden piezoelektrische Kristalle mit aufgedampften Metallstrukturen, die den internationalen Tiercode darstellen. Zum Auslesen des Tiercodes werden akustische Oberflächenwellen (Surface Acoustic Wave = SAW) ohne jegliche Energiequelle genutzt. Die SAW-Codierung und der Charakter der Funkübertragung im Mikrowellenbereich um 2,4 GHz unterscheiden sich grundlegend von der üblichen Tieridentifikation im Niederfrequenzbereich bei 134 kHz. Die Vorteile der passiven SAW-Identifikation liegen in der höheren Lesereichweite bis zu 10 m und der sehr kurzen Identifikationsdauer unter 10 ms bei hoher Erkennungssicherheit. In vier Betrieben wurde an 1.652 Milchkühen die Funktionssicherheit untersucht.

L'objectiu principal d'aquesta tesi és la caracterització de la raça bovina Bruna dels Pirineus per tal de conèixer, per una banda, la variabilitat de la raça en relació a la qualitat de la canal, la qualitat de la carn i les característiques bioquímiques del múscul longissimus thoracis (pigments hemo, percentatge de miosina MHC I mitjançant ELISA i activitats enzimàtiques lactat deshidrogenasa i isocitrat deshidrogenasa) i, per l'altra, l'estudi de les seves relacions amb les variables o atributs de l'anàlisi sensorial (olor de vedella, olor de fetge, flavor de vedella, flavor de fetge, tendresa i sucositat), a fi de poder avaluar objectivament el potencial d'aquesta raça.Un total de 74 vedells mascles de la raça Bruna dels Pirineus (provinents de 22 ramaders i engreixats al llarg dels anys 1996-98) van ser deslletats als 7 mesos de mitjana d'edat i amb un pes mitjà de 268 kg. L'alimentació del període d'engreix (171 dies de mitjana) va ser ad libitum, amb una dieta exclusivament vegetal, a base de pinso concentrat i suplementada amb farratge. El pes viu de sacrifici dels animals fou de 541,3 ±29,6 kg, amb una edat mitjana de 380,6 ±34,4 dies.A més a més, també s'estudia l'efecte raça-sistema de producció sobre el color i les característiques bioquímiques del múscul longissimus thoracis (LT) en set races autòctones espanyoles de vacum de carn amb un total de 478 vedells mascles repartits de la manera següent: 70 de l' Asturiana de los Valles (AV), 70 de l' Asturiana de la Montaña (AM), 55 de la Pirenaica (PI), 74 de la Bruna dels Pirineus (BP), 71 de l' Avileña-Negra Ibérica (A-NI), 70 de la Morucha (MO) i 68 de la Retinta (RE). Els vedells es van criar amb les mares en sistema extensiu fins a l'inici del període d'engreix (entre 5 i 7 mesos), el qual va consistir en una alimentació ad libitum i d'acord amb el sistema de producció característic de cada raça. La mitjana d'edat de sacrifici de les diferents races va oscil·lar entre els 363 i els 541dies, mentre que el pes canal es va moure entre els 250 i 334,5 kg. S'observà un efecte significatiu del raça-sistema de producció sobre el color i les característiques bioquímiques del múscul LT. / The main objective of this study was the characterisation of the Bruna dels Pirineus cattle breed in relation to carcass quality, meat quality and longissimus thoracis (LT) biochemical characteristics variability (haem pigments, myosin MHC I percentage, lactate dehydrogenase and isocitrate dehydrogenase activities), and furthermore, to examine their relationships with the sensory analysis variables (beef and livery odour intensity, beef and livery flavour intensity, tenderness and juiciness), in order to evaluate the potential of this breed.A total of 74 young bulls of the Bruna dels Pirineus Breed (from 22 herds and reared along 1996-98) were used. Calves were weaned at about 7 months old, with an average weaning-weight of 286 kg, and fed ad libitum with an exclusively vegetal diet (concentrate and supplemented with hay) during 171 days, on average. Live weight at sacrifice was 541.3 ±29.6 kg, with an average age of 380.6 ±34.4 days. Additionally, the effect of the breed-production system on the colour and the biochemical characteristics of LT muscle in seven local Spanish beef cattle breeds was studied (478 young bulls): 70 from Asturiana de los Valles (AV), 70 from Asturiana de la Montaña (AM), 55 from Pirenaica (PI), 74 from Bruna dels Pirineus (BP), 71 from Avileña-Negra Ibérica (A-NI), 70 from Morucha (MO) and 68 from Retinta (RE). Calves were reared in an extensive regime together with their mothers and started fattening at about 5 to 7 months old. They were fed a breed-specific diet ad libitum. The ingredients always had a vegetable origin. Age at slaughter was between 363 and 541 days; and carcass weight between 250 and 334.5 kg. Significant differences between breed-production systems were found for all the traits evaluated.