Quadrupole transitions and quantum gates protected by continuous dynamic decoupling

Dynamical decoupling techniques are a versatile tool for engineering quantum states with tailored properties. In trapped ions, nested layers of continuous dynamical decoupling (CDD) by means of radio-frequency field dressing can cancel dominant magnetic and electric shifts and therefore provide highly prolonged coherence times of electronic states. Exploiting this enhancement for frequency metrology, quantum simulation or quantum computation, poses the challenge to combine the decoupling with laser-ion interactions for the quantum control of electronic and motional states of trapped ions. Ultimately, this will require running quantum gates on qubits from dressed decoupled states. We provide here a compact representation of nested CDD in trapped ions, and apply it to electronic S and D states and optical quadrupole transitions. Our treatment provides all effective transition frequencies and Rabi rates, as well as the effective selection rules of these transitions. On this basis, we discuss the possibility of combining CDD and Mølmer-Sørensen gates

Alterations in Energy Partitioning and Methane Emissions in Murciano-Granadina Goats Fed Orange Leaves and Rice Straw as a Replacement for Beet Pulp and Barley Straw

[EN] Reducing methane emissions in ruminants with the recycling of agro-industrial by-products is of great importance today. Pruning waste from citrus trees is currently burned or incorporated into soil. Regarding rice straw, this waste is traditionally eliminated through controlled burning, releasing into the atmosphere large amounts of greenhouse gases as well. The aim of this study was to convert this recovered waste into a new animal feed capable of reducing methane emissions in ruminants. The interest in use waste by-products for ruminant nutrition is increasing. Therefore, we replace the beet pulp and cereal straw from dry-non-pregnant goats' diet with orange leaves and rice straw with the objective of studying their effect upon intake, digestibility, energy efficiency, carbon and nitrogen balance, and methane emissions. Considering the huge quantities of crops by-products and pruning waste such as rice straw and citrus leaves produced annually worldwide, and their potential pollution capacity, recycling as feed for livestock is an alternative. The objective was to study these by-products effect on energy balance and methane emissions in 10 Murciano-Granadina goats at maintenance. The control diet (CTR) included barley straw and beet pulp while the experimental diet (ORG) consisted of rice straw and orange leaves. Differences were found for energy intake (248 kJ/kg of BW0.75 greater for CTR than ORG). The intake of metabolizable energy was 199 kJ/kg of BW0.75 lower in ORG than CTR, and the energy efficiency was higher with CTR (0.61) than ORG (0.48). Protein retained in the body was 9 g/goat greater with CTR than ORG, and fat retention in the body was approximately 108 g/goat greater with CTR than ORG. Despite more unfavorable energy balance in response to feeding ORG than CTR, the retention of body energy was always positive. Reductions in CH4 emissions were detected when goats were fed ORG diet (from 22.3 to 20.0 g/d). Overall results suggested that feeding orange leaves and rice straw was effective in reducing CH4 emissions without adversely affecting energy balance.This study was supported by LIFE Project, Spain (ref. LIFE2016/CCM/ES/000088 LOW CARBON FEED).Romero Rueda, T.; Palomares Carrasco, JL.; Moya, V.; Loor, JJ.; Fernández Martínez, CJ. (2021). Alterations in Energy Partitioning and Methane Emissions in Murciano-Granadina Goats Fed Orange Leaves and Rice Straw as a Replacement for Beet Pulp and Barley Straw. Animals. 11(1):1-14. https://doi.org/10.3390/ani11010038S11411

Effect of increasing lignin in isoenergetic diets at two soluble fibre levels on digestion, performance and carcass quality of growing rabbits

To assess the effect of increasing dietary lignin in isoenergetic diets at two soluble fibre (SF) levels on digestion, performance and carcass quality of growing rabbits, four diets were formulated according a 2 × 2 factorial design: low SF-low lignin (LSF/LL), low SF-high lignin (LSF/HL), high SF-low lignin (HSF/LL) and high SF-high lignin (HSF/HL). On average, in HSF diets SF was increased by 49 g/kg DM, mainly replacing starch (−53 g/kg DM), and in HL diets lignin was increased by 40 g/kg, mainly reducing starch (-78 g/kg DM), with increasing EE (+31 g/kg DM). Two hundred and sixty crossbred weaned rabbits (35 days old) were assigned to the experimental diets, individually housed and fed ad libitum until 63 days of age. Digestibility (from 49 to 53 days old), growth performance (from 35 to 63 days old), carcass quality (at 63 days old) and caecal environment (at 63 days old) were studied in 12, 65, 45 and 16 rabbits per diet, respectively. High SF diets showed higher CTTAD of fibrous fractions (+0.206±0.011, +0.207±0.015, +0.214±0.011 and +0.167±0.015 for aNDFom, ADFom, hemicelluloses and cellulose, respectively, P < 0.001), OM (+0.042±0.004, P < 0.001) and GE (+0.055±0.005, P < 0.001), resulting in high DE content (10.6 vs. 9.30 MJ/kg DM). In contrast, CTTAD of CP was lower (−0.023±0.009, P = 0.013), as well as the DP content (96.9 vs. 103 g/kg DM). This dietary variation reduced the DM content of caecal digesta (−28±3 g/kg, P < 0.001), besides increasing its VFA concentration (+18.0±4.0 mmol/L, P < 0.001) and reducing its pH (−0.28±0.05, P < 0.001). Feed intake and LW gain decreased, with an improvement of feed to gain ratio (−13.8 %, −4.7 %, −9.4 %, respectively; P < 0.001). The proportion of gastrointestinal tract was increased, with a subsequent reduction in dressing out (+19±2 g/kg LW and −15±2 g chilled carcass weight/kg LW, respectively, P < 0.001). High lignin diets showed lower CTTAD of OM (-0.055±0.004, P < 0.001) and GE (−0.034±0.005, P < 0.001) without affecting DE and DP contents. This dietary variation increased DM content of caecal digesta (+21±3 g/kg, P < 0.001), but did not affect the other caecal digesta traits. Feed intake was higher (+4.9 %, P < 0.001), although differences were dependent on the growth phase and the SF level (maximum difference at 35–49 days with low SF diets, +11.0 %, P < 0.001; minimum difference at 49–63 days with high SF diets, +1.0 %, P = 0.689), but did not affect LW gain and consequently impaired the feed to gain ratio (+5.1 %, P < 0.001). No effect was observed on dressing out, but the dissectible fat proportion increased (+6.7±1.1 g/kg reference carcass weight, P < 0.001).info:eu-repo/semantics/acceptedVersio

Retroceso demográfico y recomposición del poblamiento rural en la provincia de Jaén = Demographic settlement and recomposition of the rural population in the province of Jaén

El rural jiennense sigue inmerso en un proceso de despoblación generalizado, especialmente acusado cuando se trata de áreas de montaña. Entre otros efectos, esto significa una redistribución espacial de la misma, con preferencia para los núcleos más grandes, mejor comunicados y mayor capacidad económica. El empleo de diferentes indicadores permite retratar el detalle de la situación, un paso previo a la compresión de las causas y la toma de decisiones que puedan emprenderse para mitigar sus efectos más perniciosos. Entre los resultados de esta comunicación se destacan la delimitación de los municipios que están en riesgo de despoblación y la evolución del poblamiento y los principales usos agrarios del suelo desde finales del siglo XIX hasta la actualida

Effect of Dietary Level of Beet Pulp, with or without Molasses, on Health Status, Growth Performance, and Carcass and Digestive Tract Traits of Rabbits

[EN] Beet pulp is a raw material widely used in feed for growing rabbits, because it is a good source of soluble fiber, and its inclusion is frequently associated with a reduction in the incidence of digestive disorders. Beet pulp may or may not be accompanied by the molasses that is also obtained in the beet sugar extraction process, but no information is available on the effect of molasses presence on the response of the rabbits. This work evaluates the effect of the inclusion of beet pulp, with or without molasses, on the growth performance, carcass, digestive tract, and fermentative profile of the cecum in growing rabbits. The results of the present work have shown that beet pulp linearly reduced the growth performance and carcass yield of growing rabbits and, although the inclusion of beet pulp could contribute to reducing the risk of digestive disorders, when beet pulp included molasses, even higher incidence was observed. To evaluate the effect of dietary level of beet pulp, with or without molasses, on growth performance, a total of 470 28-day-old rabbits were used (614 +/- 6 g). Animals were randomly allocated into five dietary treatment groups: Control, without beet pulp; BP20, and BP40 with 20 and 40% of beet pulp without molasses, respectively; and BPM20 and BPM40, with 20 and 40% of beet pulp with molasses, respectively. Daily feed intake (DFI) and average daily gain (ADG) were controlled at 28, 49, and 59 days of age. Carcass and digestive tract traits were also determined at 59 days of age. Mortality and morbidity were controlled daily. Mortality during the growing period was higher in BPM than in BP groups (+9.2%; p < 0.05). The higher the inclusion of beet pulp, the lower the DFI and ADG of animals (5.5 and 4.6% for every 20% inclusion, respectively; p < 0.001), as well as the dressing out percentage, the liver proportion, and the dissectible fat percentage of their carcasses. However, the best feed efficiency during the last 10 days was obtained with the BPM40 group. The higher the inclusion of beet pulp, the higher the weight of the empty gastrointestinal tract and cecum (+2.4 and +3.0 percentage points for every 20% inclusion, respectively; p < 0.001). In fact, a higher inclusion of beet pulp decreased the pH and dry matter and decreased the total volatile fatty acids content of cecum richer in acetic acid but poorer in propionic, isobutiric, isovaleric, and valeric acids. Stomach weight was lower, and the capric acid content in the cecum was higher in the BPM than in the BP group. The inclusion of beet pulp in the feed reduced the growth performance and carcass yield of growing rabbits, and an even higher incidence of digestive disorders was observed when beet pulp included molasses.This research was funded by the Spanish Ministry of Education and Science (grant no. AGL2014-53405-C2-1-P).Arce, O.; Alagón, G.; Ródenas Martínez, L.; Martinez-Paredes, E.; Moya, V.; Cervera, C.; Pascual Amorós, JJ. (2022). Effect of Dietary Level of Beet Pulp, with or without Molasses, on Health Status, Growth Performance, and Carcass and Digestive Tract Traits of Rabbits. Animals. 12(23):1-12. https://doi.org/10.3390/ani12233441112122

Nutritive Value of Wheat Bran Diets Supplemented With Fresh Carrots and Wet Brewers' Grains in Yellow Mealworm

[EN] We evaluated the effect of supplementation of a wheat bran (WB) diet with fresh carrots (FC) or wet brewer's grains (WBG) on the growth performance and chemical composition of Tenebrio molitor larvae. Additionally, a digestibility trial was performed to determine the nutritional value of the raw materials used. The control diet was based on WB-only. Two other diets were formulated in which WB was supplemented with FC (FC diet) or with WBG (WBG diet). The experiment was conducted in trays (12 per treatment) and lasted 90 d. Larval weight, feed intake, and excreted feces were controlled in each tray the experiment. The digestibility trial was performed from 48 to 62 d post-hatch. Results showed digestibility coefficients of ashes, crude protein, and gross energy were significantly higher in FC diet compared with the other diets. Consequently, both digestible energy (DE) and digestible protein (DP) contents of FC were also significantly higher than those obtained for WB and WBG diets (on av. +1.12 megajoule [MJ] DE and +9.15 g DP per kg dry matter [DM]; P < 0.003). Mealworms fed FC diet showed significantly higher final weight and average daily gain than those fed the WBG diet (+12.4%), being higher in WBG than in WB diet (+3.5%). Dietary treatment did not affect DM, ashes, ether extract, and crude protein content of mealworms obtained. Some dietary effects on amino acid and fatty acid composition were observed. This study provides novel data and a unique experimental approach to assess the nutritional value of raw materials in mealwormsWe thank Juan Cañamero (Production Manager of Feedect) for his contribution maintaining the colony and collaborating in data collection. Dr. Enrique Blas (Universitat Politècnica de València) is also thanked for contributing with his ideas, opinions, and support during the design of the experiment.Fasce, B.; Ródenas Martínez, L.; López Luján, MDC.; Moya, V.; Pascual Amorós, JJ.; Cambra López, M. (2022). Nutritive Value of Wheat Bran Diets Supplemented With Fresh Carrots and Wet Brewers' Grains in Yellow Mealworm. Journal of Insect Science. 22(3):1-9. https://doi.org/10.1093/jisesa/ieac0221922

Effect of increasing lignin in isoenergetic diets at two soluble fibre levels on digestion, performance and carcass quality of growing rabbits

[EN] To assess the effect of increasing dietary lignin in isoenergetic diets at two soluble fibre (SF) levels on digestion, performance and carcass quality of growing rabbits, four diets were formulated according a 2 x 2 factorial design: low SF-low lignin (LSF/LL), low SF-high lignin (LSF/HL), high SF-low lignin (HSF/LL) and high SF-high lignin (HSF/HL). On average, in HSF diets SF was increased by 49 g/kg DM, mainly replacing starch ( - 53 g/kg DM), and in HL diets lignin was increased by 40 g/kg, mainly reducing starch (-78 g/kg DM), with increasing EE ( + 31 g/kg DM). Two hundred and sixty crossbred weaned rabbits (35 days old) were assigned to the experimental diets, individually housed and fed ad libitum until 63 days of age. Digestibility (from 49 to 53 days old), growth performance (from 35 to 63 days old), carcass quality (at 63 days old) and caecal environment (at 63 days old) were studied in 12, 65, 45 and 16 rabbits per diet, respectively. High SF diets showed higher CTTAD of fibrous fractions ( + 0.206 +/- 0.011, + 0.207 +/- 0.015, + 0.214 +/- 0.011 and + 0.167 +/- 0.015 for aNDFom, ADFom, hemicelluloses and cellulose, respectively, P < 0.001), OM ( + 0.042 +/- 0.004, P < 0.001) and GE ( + 0.055 +/- 0.005, P < 0.001), resulting in high DE content (10.6 vs. 9.30 MJ/kg DM). In contrast, CTTAD of CP was lower ( - 0.023 +/- 0.009, P = 0.013), as well as the DP content (96.9 vs. 103 g/kg DM). This dietary variation reduced the DM content of caecal digesta ( - 28 +/- 3 g/kg, P < 0.001), besides increasing its VFA concentration ( + 18.0 +/- 4.0 mmol/L, P < 0.001) and reducing its pH ( - 0.28 +/- 0.05, P < 0.001). Feed intake and LW gain decreased, with an improvement of feed to gain ratio ( -13.8 %, - 4.7 %, - 9.4 %, respectively; P < 0.001). The proportion of gastrointestinal tract was increased, with a subsequent reduction in dressing out ( + 19 +/- 2 g/kg LW and -15 +/- 2 g chilled carcass weight/kg LW, respectively, P < 0.001). High lignin diets showed lower CTTAD of OM (-0.055 +/- 0.004, P < 0.001) and GE ( - 0.034 +/- 0.005, P < 0.001) without affecting DE and DP contents. This dietary variation increased DM content of caecal digesta ( +21 +/- 3 g/kg, P < 0.001), but did not affect the other caecal digesta traits. Feed intake was higher ( + 4.9 %, P < 0.001), although differences were dependent on the growth phase and the SF level (maximum difference at 35-49 days with low SF diets, + 11.0 %, P < 0.001; minimum difference at 49-63 days with high SF diets, + 1.0 %, P = 0.689), but did not affect LW gain and consequently impaired the feed to gain ratio ( + 5.1 %, P < 0.001). No effect was observed on dressing out, but the dissectible fat proportion increased ( + 6.7 +/- 1.1 g/kg reference carcass weight, P < 0.001).Financial support was provided by the Spanish Ministry of Education and Science (Project AGL2006-07596).Caisin, L.; Martinez-Paredes, E.; Ródenas Martínez, L.; Moya, V.; Pascual Amorós, JJ.; Cervera Fras, MC.; Blas Ferrer, E.... (2020). Effect of increasing lignin in isoenergetic diets at two soluble fibre levels on digestion, performance and carcass quality of growing rabbits. Animal Feed Science and Technology. 262:1-9. https://doi.org/10.1016/j.anifeedsci.2020.114396S19262Batey, I. L. (1982). Starch Analysis Using Thermostable alpha-Amylases. Starch - Stärke, 34(4), 125-128. doi:10.1002/star.19820340407Delgado, R., Nicodemus, N., Abad-Guamán, R., Sastre, J., Menoyo, D., Carabaño, R., & García, J. (2018). Effect of dietary soluble fibre and n-6/n-3 fatty acid ratio on growth performance and nitrogen and energy retention efficiency in growing rabbits. Animal Feed Science and Technology, 239, 44-54. doi:10.1016/j.anifeedsci.2018.03.006Delgado, R., Menoyo, D., Abad-Guamán, R., Nicodemus, N., Carabaño, R., & García, J. (2019). Effect of dietary soluble fibre level and n-6/n-3 fatty acid ratio on digestion and health in growing rabbits. Animal Feed Science and Technology, 255, 114222. doi:10.1016/j.anifeedsci.2019.114222Fernández, C., & Fraga, M. J. (1996). The effect of dietary fat inclusion on growth, carcass characteristics, and chemical composition of rabbits. Journal of Animal Science, 74(9), 2088. doi:10.2527/1996.7492088xGarcía, J., Gidenne, T., Luisa Falcao-e-Cunha, & de Blas, C. (2002). Identification of the main factors that influence caecal fermentation traits in growing rabbits. Animal Research, 51(2), 165-173. doi:10.1051/animres:2002011Gidenne, T. (2015). Dietary fibres in the nutrition of the growing rabbit and recommendations to preserve digestive health: a review. Animal, 9(2), 227-242. doi:10.1017/s1751731114002729Gidenne, T., Perez, J., Lapanouse, A., & Ségura, M. (1994). Apports de lignines et alimentation du lapin en croissance. I. Conséquences sur la digestion et le transit. Annales de Zootechnie, 43(4), 313-322. doi:10.1051/animres:19940401Gidenne, T., Arveux, P., & Madec, O. (2001). The effect of the quality of dietary lignocellulose on digestion, zootechnical performance and health of the growing rabbit. Animal Science, 73(1), 97-104. doi:10.1017/s1357729800058094Grueso, I., De Blas, J. C., Cachaldora, P., Mendez, J., Losada, B., & García-Rebollar, P. (2013). Combined effects of supplementation of diets with hops and of a substitution of starch with soluble fiber on feed efficiency and prevention of digestive disorders in rabbits. Animal Feed Science and Technology, 180(1-4), 92-100. doi:10.1016/j.anifeedsci.2013.01.009Martínez-Vallespín, B., Martínez-Paredes, E., Ródenas, L., Cervera, C., Pascual, J. J., & Blas, E. (2011). Combined feeding of rabbit female and young: Partial replacement of starch with acid detergent fibre or/and neutral detergent soluble fibre at two protein levels. Livestock Science, 141(2-3), 155-165. doi:10.1016/j.livsci.2011.05.014Martínez-Vallespín, B., Martínez-Paredes, E., Ródenas, L., Moya, V. J., Cervera, C., Pascual, J. J., & Blas, E. (2013). Partial replacement of starch with acid detergent fibre and/or neutral detergent soluble fibre at two protein levels: Effects on ileal apparent digestibility and caecal environment of growing rabbits. Livestock Science, 154(1-3), 123-130. doi:10.1016/j.livsci.2013.02.012Nicodemus, N., Carabaño, R., Garcı́a, J., Méndez, J., & de Blas, C. (1999). Performance response of lactating and growing rabbits to dietary lignin content. Animal Feed Science and Technology, 80(1), 43-54. doi:10.1016/s0377-8401(99)00042-5Ocasio-Vega, C., Delgado, R., Abad-Guamán, R., Carabaño, R., Carro, M. D., Menoyo, D., & García, J. (2018). The effect of cellobiose on the health status of growing rabbits depends on the dietary level of soluble fiber. Journal of Animal Science, 96(5), 1806-1817. doi:10.1093/jas/sky106Pascual, M., Soler, M. D., Cervera, C., Pla, M., Pascual, J. J., & Blas, E. (2014). Feeding programmes based on highly-digestible fibre weaning diets: Effects on health, growth performance and carcass and meat quality in rabbits. Livestock Science, 169, 88-95. doi:10.1016/j.livsci.2014.07.007Trocino, A., García Alonso, J., Carabaño, R., & Xiccato, G. (2013). A meta-analysis on the role of soluble fibre in diets for growing rabbits. World Rabbit Science, 21(1). doi:10.4995/wrs.2013.1285Trocino, A., Fragkiadakis, M., Majolini, D., Tazzoli, M., Radaelli, G., & Xiccato, G. (2013). Soluble fibre, starch and protein level in diets for growing rabbits: Effects on digestive efficiency and productive traits. Animal Feed Science and Technology, 180(1-4), 73-82. doi:10.1016/j.anifeedsci.2013.01.007Van Soest, P. J., Robertson, J. B., & Lewis, B. A. (1991). Methods for Dietary Fiber, Neutral Detergent Fiber, and Nonstarch Polysaccharides in Relation to Animal Nutrition. Journal of Dairy Science, 74(10), 3583-3597. doi:10.3168/jds.s0022-0302(91)78551-2Xiccato, G., Trocino, A., Majolini, D., Fragkiadakis, M., & Tazzoli, M. (2011). Effect of decreasing dietary protein level and replacing starch with soluble fibre on digestive physiology and performance of growing rabbits. Animal, 5(8), 1179-1187. doi:10.1017/s175173111100024

Nutritive value of distillers dried grains with solubles from barley, corn and wheat for growing rabbits

The authors acknowledge Juan Carlos Moreno for his technical support and the Spanish Ministry of Education and Science (Project AGL2014-53405-C2-1-P) for the economic support to conduct this study.Alagon, G.; Arce-Cabrera, ON.; Martinez-Paredes, E.; Ródenas Martínez, L.; Moya, V.; Blas Ferrer, E.; Cervera Fras, MC.... (2016). Nutritive value of distillers dried grains with solubles from barley, corn and wheat for growing rabbits. Animal Feed Science and Technology. 222:217-226. https://doi.org/10.1016/j.anifeedsci.2016.10.024S21722622

Replacement of Cereal with Low Starch Fibrous By-Products on Nutrients Utilization and Methane Emissions in Dairy Goats

[EN] Feeding systems for dairy ruminants need to ensure high intake of energy to achieve maximum milk production potential. This might be accomplished by raising the dietary concentration of cereal grain. Increasing the concentration of starch in diets can lead to undesirable ruminal fermentation, and to prevent it, the partial replacement of cereal grain with low starch by-product feeds is recommended. The purpose of the present study was to compare the effect of fed two mixed diets to dairy goats differing in the type of carbohydrate (starch vs. easily degradable fiber). Energy and nitrogen balance, short chain fatty acids in rumen liquor and milk performance in dairy goats during mid lactation were determined. Enteric methane (CH4) emissions and CH4 production from manure were determined as well. Ten multiparous Muciano-Granadina goats were assigned to two isoenergetic and isoproteic diets (19.1 MJ/kg dry matter (DM) and 18.1% of CP, DM basis) in a crossover design. One group was fed a mixed ration with 21.9% of starch (HS diet) and the other (LS diet) with 7.0% of starch. HS diet had 36% of barley (as source of starch) and it was replaced with soy hulls and corn gluten feed in LS diet (as potentially digestible fiber). No differences were observed for dry matter intake in both diets (2.05 kg/d, on average). A significant increase of ruminal acetic acid was found for low starch diet (66.4 and 56.6 mol/100 mol for LS and HS diet, respectively). No significant effect was found among diets for enteric CH4 emissions (28.5 g/d, on average). Manure derived maximum potential yield was (Bo) higher in HS diet, with 5.9 L CH4/kg OM vs. 0.28 L CH4/kg OM for LS diet, probably associated with the low ADF digestibility. Differences among diets were found for milk production (2.4 vs. 2.2 kg/d for HS and LS, respectively), and greater milk fat was observed with LS diet compared with HS (6.4% vs. 5.5%, respectively).This study was supported by INIA Project, Spain (ref. RTA2011-00107-C02).Ibáñez Sanchis, C.; Moya, V.; Arriaga, H.; López, DM.; Merino, P.; Fernández Martínez, CJ. (2015). Replacement of Cereal with Low Starch Fibrous By-Products on Nutrients Utilization and Methane Emissions in Dairy Goats. Open Journal of Animal Sciences. 5(2):198-209. https://doi.org/10.4236/ojas.2015.52022S1982095

Partial replacement of starch with acid detergent fibre and/or neutral detergent soluble fibre at two protein levels: Effects on ileal apparent digestibility and caecal environment of growing rabbits

[EN] The effects of the composition of pen-weaning diets on apparent ileal digestibility of nutrients and caecal environment were studied in growing rabbits. Eight diets were formulated according to a 2 x 2 x 2 factorial design to increase acid detergent fibre (ADF) from 230 to 290 g kg(-1) dry matter (DM) at the expense of mainly starch, to increase neutral detergent soluble fibre (NDSF) from 145 to 185 g kg(-1) DM at the expense of mainly starch, and to reduce crude protein (CP) content from 175 to 145 g kg(-1) DM. A total of 32 litters of eight kits were randomly assigned to the diets at 17 days of age, weaned at 28 days of age and slaughtered at 35 days of age to collect samples of ileal and caecal contents. The substitution of ADF for starch reduced the coefficient of apparent ileal digestibility (CAID) of DM (0.292 vs. 0.229; P <0.01). The substitution of NDSF for starch increased the CAID of NDSF (-0.040 vs. 0.099; P < 0.01). An interaction between dietary ADF and NDSF levels was found for the CAID of CP, higher in the low ADF-low NDSF diets than in the rest (+0.074; P <0.05). The reduction of dietary CP content decreased the CAID of CP (0.578 vs. 0.525; P < 0.05) and NDSF (0.086 vs. -0.038; P <0.01). Interactions between dietary ADF and NDSF levels were found affecting full caecum weight as well as DM content and pH of caecal digesta. The increase of ADF in the high NDSF diets reduced full caecum weight (-9.1 g kg(-1) live weight; P < 0.01), increased DM content of caecal digesta (+31 g kg(-1); P <0.001) and reduced caecal pH (- 0.10; P < 0.05). In the low NDSF diets, higher ADF increased DM content of caecal digesta to a lesser extent (+16 g kg(-1); P < 0.001) and increased caecal pH (+0.08; P <0.05). The increase of NDSF in the high ADF diets increased full caecum weight (+8.5 g kg(-1) live weight; P <0.01) and reduced caecal pH (-0.14; P <0.001). In the low ADF diets, higher NDSF increased full caecum weight more extensively (+15.5 g kg(-1) live weight; P < 0.001) and reduced DM content of caecal digesta (-16 g kg(-1); P <0.001). Both ADF and NDSF replacing starch increased total volatile fatty acid (VFA) concentration of caecal digesta (+11.5% and +13.9%, respectively; P < 0.01). The replacement with NDSF increased molar proportion of butyrate (0.095 vs. 0.112; P <0.001) at the expense of mainly acetate (0.841 vs. 0.820; P <0.001) and reduced ammonia concentration of caecal digesta (-8.1%; P < 0.05). The reduction of dietary CP content decreased total VFA (-14.4%; P < 0.001) and ammonia (-23.5%; P < 0.001) concentrations of caecal digesta and increased caecal pH (5.87 vs. 5.93; P <0.05). Overall, the three dietary changes under study led to changes in the caecal environment which might be effective in reducing mortality rate in a context of rabbit epizootic enteropathy. (C) 2013 Elsevier B.V. All rights reserved.Financial support was provided by the Ministerio de Educacion y Ciencia of Spain (Proyecto AGL2006-07596). Authors thank J. Garcia from the Universidad Politecnica de Madrid (Spain) for the analyses of ytterbium.Martínez Vallespín, B.; Martinez-Paredes, E.; Ródenas Martínez, L.; Moya, V.; Cervera Fras, MC.; Pascual Amorós, JJ.; Blas Ferrer, E. (2013). Partial replacement of starch with acid detergent fibre and/or neutral detergent soluble fibre at two protein levels: Effects on ileal apparent digestibility and caecal environment of growing rabbits. Livestock Science. 154(1-3):123-130. https://doi.org/10.1016/j.livsci.2013.02.012S1231301541-