Determination of faecal dry matter digestibility two weeks after weaning in twenty five day old weaned rabbits

[EN] The aim of this work was to analyse the evolution from 26 to 40 d of age of apparent faecal dry matter digestibility (DMd) in rabbits weaned at 25 d of age to define how to determine nutrient digestibility in the post-weaning period. Fifteen New Zealand ' Californian rabbits from five litters (3 rabbits/litter) weaned at 25 d of age and weighing 602±75g were fed ad libitum a commercial diet containing 20.0% crude protein and 33.5% NDF (on DM basis). Feed intake and faeces excretion were recorded daily from 25 to 40 d of age and DM digestibility determined. Litter affected DM intake and excretion (P = 0.013 and 0.014, respectively), and tended to affect DMd (P = 0.061), whereas age influenced all these traits (P < 0.001). Dry matter intake and DM excretion increased from 26 to 40 d of age by 158 and 480%, respectively. During the first week after weaning, DM intake increased more slowly than DM excretion (55 vs. 245%), but in the second week after weaning both increased by 67%. The correlation between daily feed intake was higher with the faeces excretion of the same day than with faeces excretion of the next day, and the first values were used to determine daily DMd. A broken line regression model was fitted to daily DMd, which decreased linearly from weaning to 32 d of age (2.17 ± 0.25 percentage units per day), whereas from 32 to 40 d it remained constant (69.4 ± 0.47%). Accordingly, for 25-d old weaned rabbits it would be advisable to begin a digestibility trial not before 32 d of age, using the first week after weaning as adaptation period. Average standard deviation of DMd decreased by 54% when the length of the collection period increased from 2 to 6 d. Consequently, the number of animals required to detect a significant difference among means depends on the length of the collection period. For a conventional collection period of four days, a difference of 2 percentage units could be detected by using 14 animals/treatment.Gómez-Conde, M.; García, J.; Villamide, M.; Carabaño, R. (2011). Determination of faecal dry matter digestibility two weeks after weaning in twenty five day old weaned rabbits. World Rabbit Science. 19(1):43-48. doi:10.4995/wrs.2011.816SWORD434819

Quantification of soluble fibre in feedstuffs for rabbits and evaluation of the interference between the determinations of soluble fibre and intestinal mucin.

This work compared the quantification of soluble fibre in feeds using different chemical and in vitro approaches, and studied the potential interference between soluble fibre and mucin determinations. Six ingredients: sugar beet pulp (SBP), SBP pectins, insoluble SBP, wheat straw, sunflower hulls and lignocellulose, and seven rabbit diets, differing in soluble fibre content, were evaluated. In experiment 1, ingredients and diets were analyzed for total dietary fibre (TDF), insoluble dietary fibre (IDF), soluble dietary fibre (SDF), aNDFom (corrected for protein, aNDFom-cp) and 2-step pepsin/pancreatin in vitro DM indigestibility (corrected for ash and protein, ivDMi2). Soluble fibre was estimated by difference using three procedures: TDF?IDF (SDFIDF), TDF?ivDMi2 (SDFivDMi2), and TDF?aNDFom-cp (SDFaNDFom-cp). Soluble fibre determined directly (SDF) or by difference as SDFivDMi2 were not different (109 g/kg DM, on average). However, when it was calculated as SDFaNDFom-cp the value was 40% higher (153 g/kg DM, P menor que 0.05), whereas SDFIDF (124 g/kg DM) did not differ from any of the other methods. The correlation between the four methods was high (r ? 0.96; P ? 0.001; n = 13), but it decreased or even disappeared when SBP pectins and SBP were excluded and a lower and more narrow range of variation of soluble fibre was used. In experiment 2, the ivDMi2 using crucibles (reference method) were compared to those made using individual or collective ankom bags in order to simplify the determination of SDFivDMi2. The ivDMi2 was not different when using crucibles or individual or collective ankom bags. In experiment 3, the potential interference between soluble fibre and intestinal mucin determinations was studied using rabbit intestinal raw mucus, digesta and SBP pectins, lignocelluloses and a rabbit diet. An interference was observed between the determinations of soluble fibre and crude mucin, as contents of TDF and apparent crude mucin were high in SBP pectins (994 and 709 g/kg DM) and rabbit intestinal raw mucus (571 and 739 g/kg DM). After a pectinase treatment, the coefficient of apparent mucin recovery of SBP pectins was close to zero, whereas that of rabbit mucus was not modified. An estimation of the crude mucin carbohydrates retained in digesta TDF is proposed to correct TDF and soluble fibre digestibility. In conclusion, the values of soluble fibre depend on the methodology used. The contamination of crude mucin with soluble fibre is avoided using pectinase

In vitro caecal fermentation of carbohydrate-rich feedstuffs in rabbits as affected by substrate pre-digestion and donors' diet

[EN] The influence of substrate pre-digestion and donors’ diet on in vitro caecal fermentation of different substrates in rabbits was investigated. Eight crossbreed rabbits were fed 2 experimental diets containing either low (LSF; 84.0 g/kg dry matter [DM]) or high soluble fibre (HSF; 130 g/kg DM) levels. In vitro incubations were conducted using batch cultures with soft faeces as inoculum and four fibrous or fibre-derived, low-starch and low-protein substrates: D-cellobiose (CEL), sugar beet pectin (PEC), sugar beet pulp (SBP) and wheat straw (WS). Substrates in half of the cultures were subjected to a 2-step pepsin/pancreatin in vitro digestion without filtration, and the whole residue (soluble, insoluble and added enzymes) was incubated at 39°C. Gas production was measured until 144 h, and volatile fatty acid (VFA) production at 24 h incubation was determined. Cultures without substrate (blanks) were included to correct gas production values for gas released from endogenous substrates and added enzymes. Pre-digestion had no influence on in vitro gas production kinetic of WS, and only reduced the time before gas production begins (lag time; by 31%; P=0.042) for SBP, but for both substrates the pre-digestion decreased the molar proportion of acetate (by 9%; P≤0.003) and increased those of propionate and butyrate (P≤0.014). For CEL, the pre-digestion increased the gas and total VFA production (by 30 and 114%), shortened the lag time (by 32%), and only when it was combined with LSF inoculum 38 percentage units of acetate were replaced by butyrate (P≤0.039). Treatments had a minor influence on in vitro fermentation traits of SBP pectin. The results showed that the pre-digestion process influenced the in vitro caecal fermentation in rabbits, but the effects were influenced by donors’ diet and the incubated substrate. Pre-digestion of substrate is recommended before conducting in vitro caecal fermentations. The level of soluble fibre in the donors’ diet also influenced the in vitro caecal fermentation, but its effect depended on the type of substrate.Funding from the Spanish Ministry of Economy and Competitiveness (Projects AGL2011-23885 and AGL2011-22628) and the Comunidad Autónoma de Madrid (CAM; Project MEDGAN ABI-2913) is gratefully acknowledged.Ocasio-Vega, C.; Abad-Guamán, R.; Delgado, R.; Carabaño, R.; Carro, M.; García, J. (2018). In vitro caecal fermentation of carbohydrate-rich feedstuffs in rabbits as affected by substrate pre-digestion and donors' diet. World Rabbit Science. 26(1):15-25. https://doi.org/10.4995/wrs.2018.7854SWORD152526

Efecto de las fracciones soluble en insoluble de la fibra de la pulpa de manzana sobre la digestibilidadi ileal y fecal en conejos

El objetivo del presente trabajo fue estudiar el efecto de la fibra soluble e insoluble de pulpa de manzana sobre la digestibilidad ileal y fecal en conejos. Se formularon cuatro piensos con niveles similares de fibra insoluble (FND 32,4%) y proteína (18,6%, ambos sobre MS). El nivel de fibra soluble fue bajo en el pienso control (4,6%, su fibra procedió de cascarilla de avena y paja) y aumentó en los piensos con pulpa de manzana depectinizada (7,1%), pulpa de manzana (9,3%) y pectinas de manzana (10,5%). Se determinó la digestibilidad fecal en 23 gazapos/pienso entre los 55 y los 59 d de edad, y se sacrificaron 23 gazapos/pienso a los 60 d de edad para proteger la digesta ileal y determinar la digestibilidad ileal

Evolución con la edad de los mecanismos de barrera intestinal

Se destetaron 106 gazapos de 20 camadas a los 26 d de edad con un peso de 429 ± 57 g y se sacrificó 1 animal por camada a los 26, 31, 38, 45 y 52 d de edad. La longitud de las vellosidades intestinales y la profundidad de las criptas en el yeyuno se redujeron entre los 26 y los 31 d en un 26 y 9% respectivamente. De los 31 a los 38 días se observó un aumento tanto de la longitud de las vellosidades como de las criptas. A partir de esta edad no se observaron cambios en las vellosidades, que mostraron valores similares a las determinadas en el destete, mientras que las criptas siguieron aumentando ligeramente (9%). El grado de similitud de la microbiota cecal entre animales de la misma edad (que varió entre un 89, 1 y un 95,3%) fue superior al grado de similitud entre animales de diferentes edades (que varió entre un 82,3% y un 92,5%). La variabilidad en la composición de la microbiota fue menor a los 45 y 52 d de edad (mostrando un grado de similitud del 92,5% entre ambas edades) en comparación con la observada entre las primeras edades (26, 31 y 38 d, que varió entre 82,3 y 86,7%). Los menores grados de similitud se observaron entre los animales lactantes y los animales de 31 y 38 d de edad

Efecto de la suplementación con arginina y glutamina sobre la digestiblidad ileal y fecal de gazapos tras el destete

Se estudió el efecto de la suplementación con arginina y glutamina así como su posible interacción sobre la digestibilidad ileal y fecal de los nutrientes en gazapos tras el destete. Para ello se formuló una dieta basal (C) y se fabricaron otros 3 piensos añadiendo un 0,4% de arginina (ARG), un 0,4% de glutamina (GLN) y una mezcla de un 0,4% de arginina y un 0,4% de glutamina (ARG+GLN) a la ración basal. Se observó una interacción ARG×GLN en la digestibilidad fecal de la EB y el N (P = 0,008 y P = 0,001 respectivamente). La suplementación con ARG o GLN mejoró la digestibilidad de estos componentes en comparación con el pienso control, si bien cuando el pienso estuvo suplementado con ambos aminoácidos ARG+GLN mostró valores intermedios entre el grupo control y los suplementados con ARG o GLN (P < 0,001). La digestibilidad fecal de la FND fue superior en los piensos suplementados con GLN (P < 0,001). Los tratamientos no modificaron la digestibilidad ileal de la MS ni del N (P ≥ 0,44). La suplementación con glutamina tendió a incrementar la digestibilidad ileal del ácido glutámico (P = 0,099) respecto a los gazapos no suplementados, mientras que no afectó a la digestibilidad ileal de los demás aminoácidos (P ≥ 0,13). La suplementación con arginina + glutamina aumentó o tendió a aumentar la digestibilidad ileal aparente de la mayor parte de los aminoácidos esenciales y no esenciales de los gazapos de 35 d de edad (P < 0,096) respecto a la suplementación con glutamina

Análisis de ciclo de vida de una nueva solución arquitectónica que mejora el rendimiento térmico de la envolvente del edificio: Fachada Natural Aljibe

The objective of this work, that improves the enclosure’s thermal performance of the building, is to divulge the environmental impacts tied to a new solution of vegetated façade by means of the Life Cycle Assessment methodology with a cradle to grave system boundary. The analysis aims also at generating relevant information of the life cycle as base material for drafting a future Environmental Product Declaration. The façade’s component manufacture stage is the one presenting the highest contribution for all the analysed impact categories, with the vegetated layer being the one with the greatest impact. Conversely, the transport stage is the one presenting the least contribution, and can be considered negligible for all the analysed impact categories. Following the analysis of the results, we have obtained useful information about the most problematic aspects and components in the assessed façade’s performance, thus paving the way towards possible actions of impact reduction by the manufacturer.El objetivo de este trabajo, que supone la mejora del rendimiento térmico de la envolvente del edificio, es dar a conocer los impactos ambientales asociados a una nueva solución de fachada vegetada mediante la metodología de Análisis de Ciclo de Vida con límites del sistema de la cuna a la tumba. El análisis pretende también generar información relevante de ciclo de vida como material de partida para la redacción de una futura Declaración Ambiental de Producto. La etapa de fabricación de los componentes de la fachada es la que más contribución presenta en todas las categorías de impacto analizadas, siendo la capa vegetada la de mayor impacto. En cambio, la etapa de transporte es la que presenta menor contribución, pudiendo ser considerado despreciable para todas las categorías de impacto analizadas. Tras el análisis de los resultados, se ha obtenido información útil de los aspectos y componentes más problemáticos en el desempeño ambiental de la fachada evaluada, abriendo el camino hacia posibles acciones de reducción de impactos por parte del fabricante

Utilización de bolsas ANKOM® en la determinación de la digestibilidad de la materia seca in vitro en conejos.

La metodología de digestibilidad in vitro de la materia seca (DMSiv) desarrollada por Ramos et al. (1992) para predecir la digestibilidad de la materia seca y valor nutricional de diferentes alimentos comúnmente utilizados en la alimentación de conejos, ha sido estandarizada y validada por diferentes laboratorios (Villamide et al. 2008 y Carabaño et al. 2008), demostrándose su fiabilidad, reproducibilidad y repetibilidad. Uno de los puntos críticos de las metodologías gravimétricas es la filtración con crisol, ya que las propiedades físicas junto con la composición química de diversas materias primas dificultan este proceso y aumentan la variabilidad en los resultados (Mertens, 2002). Por otra parte la digestión individual de las muestras limita la capacidad de análisis. Con la finalidad de corregir estas limitaciones se propuso como alternativa el uso de bolsas ANKOM ® , ya utilizadas en el análisis secuencial de Van Soest (Kenneth et al., 1999), digeridas colectivamente en un mismo recipiente. Además de la utilización de bolsas, como novedad se incluyó al final de la digestibilidad un lavado adicional de las bolsas. El objetivo de este trabajo fue determinar la validez de esta modificación en la digestibilidad in vitro ileal (dos pasos) y fecal (tres pasos

Efecto del nivel de fibra soluble y de la relación omega6 y omega3 sobre los balances de nitrógeno y energía de conejos en cebo

La inclusión de pulpa de remolacha en sustitución de cebada reduce la eficacia de retención de la energía y el rendimiento de la canal, especialmente cuando su nivel de inclusión supera el 15% (De Blas y Carabaño, 1996). Aproximadamente, este es el nivel requerido para satisfacer las recientes recomendaciones de fibra soluble (Trocino et al., 2013). Por el contrario, cuando la pulpa de remolacha sustituye al heno de alfalfa no empeora la eficacia de retención de la energía (Carabaño et al., 1997)

Effects of type and level of fibre on digestive physiology and performance in reproducing and growing rabbits

The study aimed to evaluate the effect of level and type of fibre on performance and digestive traits of lactating does and growing rabbits. Two lactation diets were formulated to contain a similar level of NDF (29%): a mixture of alfalfa hay and wheat straw in diet L1 was substituted with apple pulp in diet L2. Three fattening diets were formulated: diet F1 was the same than diet L1 whereas F2 and F3 had higher level of NDF (33 and 36%, respectively) with a mixture of wheat straw and alfalfa hay in diet F2 substituted by apple pulp in diet F3. A total of 110 does and their litters were controlled during two consecutive lactations from 21 to 35 d. At weaning (35 days of age) 480 rabbits were housed collectively (four per cage) and 180 individually. Another 54 rabbits were slaughtered to determine digestive traits at 45 days of age. At 35 days of age, L1 rabbits showed 5.9 and 6.9% higher daily feed intake and body weight than L2 rabbits. In the fattening period (35 to 63 days), L1 rabbits showed a higher growth rate but a lower feed efficiency than L2 animals. In the fattening period, F1 rabbits showed a 5.9% higher weight gain and 8.8% lower feed conversion than F2 animals, whereas animals fed diet F2 had a higher weight gain (7.6%) and a worse feed conversion (6.5%) than animals fed diet F3. The highest apparent ileal digestibility of DM values was obtained for diets F1 and F3. Villi length tended to be longer (P<0.10) in animals fed the diet F1 and F3. No significant influence of treatments was detected on caecal pH, anaerobic bacteria counting or rabbit mortality (only 0.9% on average). In conclusion the substitution of a mixture of wheat straw and alfalfa hay by apple pulp in isofibrous diets increases feed efficiency but also impairs feed intake and growth rate. Furthermore, in a context of low mortality, diets with 29-30% NDF would lead to better performances in the fattening period than diets containing 33-36% NDF levels.This work was supported by a CDTI Project 04-0136.Alvarez, J.; Marguenda, I.; García-Rebollar, P.; Carabaño, R.; Blas, CD.; Corujo, A.; García-Ruiz, A. (2007). Effects of type and level of fibre on digestive physiology and performance in reproducing and growing rabbits. World Rabbit Science. 15(1):9-17. doi:10.4995/wrs.2007.61091715