Progressive congestion management based on packet marking and validation techniques

© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Congestion management in multistage interconnection networks is a serious problem, which is not solved completely. In order to avoid the degradation of network performance when congestion appears, several congestion management mechanisms have been proposed. Most of these mechanisms are based on explicit congestion notification. For this purpose, switches detect congestion and depending on the applied strategy, packets are marked to warn the source hosts. In response, source hosts apply some corrective actions to adjust their packet injection rate. Although these proposals seem quite effective, they either exhibit some drawbacks or are partial solutions. Some of them introduce some penalties over the flows not responsible for congestion, whereas others can cope only with congestion situations that last for a short time. In this paper, we present an overview of the different strategies to detect and correct congestion in multistage interconnection networks, and propose a new mechanism referred to as Marking and Validation Congestion Management (MVCM), targeted to this kind of lossless networks, and based on a more refined packet marking strategy combined with a fair set of corrective actions, that makes the mechanism able to effectively manage congestion regardless of the congestion degree. Evaluation results show the effectiveness and robustness of the proposed mechanism.This work was supported by the Spanish MEC and MICINN, as well as European Commission FEDER funds, under Grants CSD2006-00046 and TIN2009-14475-C04-01.Ferrer Pérez, JL.; Baydal Cardona, ME.; Robles Martínez, A.; López Rodríguez, PJ.; Duato Marín, JF. (2012). Progressive congestion management based on packet marking and validation techniques. IEEE Transactions on Computers. 61(9):1296-1309. doi:10.1109/TC.2011.146S1296130961

A moderate protein diet does not cover the requirements of growing rabbits with high growth rate

[EN] Genetic selection for feed efficiency has increased the growth rate and requirements of growing rabbits, while the protein content of commercial feeds has been adjusted to avoid digestive disorders. The aim of this work was to evaluate how a diet with moderate levels of protein content [146 g crude protein (CP)/kg] could be affecting protein and amino acids acquisition depending on the growth rate of the animals. From 189 weaned rabbits (28 days old), only 41 animals were selected at 42 days, in order to ensure the greatest variability for growth rate during fattening. To achieve this goal, animals came from three genetic lines: H and LP (maternal lines selected by litter size) and R (paternal line selected for growth rate), characterised by normal, moderate and high growth rate during the fattening period, respectively. Apparent faecal digestibility of dry matter (DM), CP and gross energy (GE) of the diet from 49-53 days of age, as well as the ileal apparent digestibility of DM, CP and amino acids at 63 days of age, was determined in all the selected animals. Protein, energy and amino acids retained in the empty body during the fattening period were also determined by slaughtering 15 weaning rabbits at 28 days, and the 41 selected animals at 63 days of age. Animals from the R line showed higher feed intake than those from maternal lines, as well as lower feed conversion ratio, even below that expected from their growth rate. Apparent faecal digestibility of GE and apparent ileal digestibility of DM, CP and cystine of the diet were higher in LP than in H rabbits (P < 0.05), showing intermediate values in R rabbits. However, apparent ileal digestibility of glutamic acid and glycine was significantly higher in R than in H rabbits (P < 0.05), showing intermediate values in LP rabbits. As expected, both daily protein and energy retained in the empty body increased as growth increased. However, R growing rabbits seem to have lower protein retained and higher energy retained in the empty body than that expected from their growth. In fact, protein to energy retained ratio was clearly lower for R growing rabbits. These results seem to show the possible existence of some limiting amino acid when current moderate protein diets are used in growing rabbits with high growth rates, recommending a review of the amino acid requirements for the growing rabbits from paternal lines.This study was supported by the Interministerial Commission for Science and Technology (CICYT) from the Spanish Government (AGL2017-85162-C2-1-R). The grant for Pablo Marin from the Ministry of Education, Culture and Sports (FPU-2014-01203) is also gratefully acknowledged.Marín-García, P.; Ródenas Martínez, L.; Martinez-Paredes, E.; Cambra López, M.; Blas Ferrer, E.; Pascual Amorós, JJ. (2020). A moderate protein diet does not cover the requirements of growing rabbits with high growth rate. Animal Feed Science and Technology. 264:1-11. https://doi.org/10.1016/j.anifeedsci.2020.114495S111264Alagón, G., Arce, O. N., Martínez-Paredes, E., Ródenas, L., Moya, V. J., Blas, E., … Pascual, J. J. (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. doi:10.1016/j.anifeedsci.2016.10.024Batey, I. L. (1982). Starch Analysis Using Thermostable alpha-Amylases. Starch - Stärke, 34(4), 125-128. doi:10.1002/star.19820340407Birolo, M., Trocino, A., Zuffellato, A., & Xiccato, G. (2016). Effect of feed restriction programs and slaughter age on digestive efficiency, growth performance and body composition of growing rabbits. Animal Feed Science and Technology, 222, 194-203. doi:10.1016/j.anifeedsci.2016.10.014Cartuche, L., Pascual, M., Gómez, E. A., & Blasco, A. (2014). Economic weights in rabbit meat production. World Rabbit Science, 22(3), 165. doi:10.4995/wrs.2014.1747Cifre, J., Baselga, M., García-Ximénez, F., & Vicente, J. S. (1998). Performance of a hyperprolific rabbit line I. Litter size traits. Journal of Animal Breeding and Genetics, 115(1-6), 131-138. doi:10.1111/j.1439-0388.1998.tb00336.xCosta, C., Baselga, M., Lobera, J., Cervera, C., & Pascual, J. J. (2004). Evaluating response to selection and nutritional needs in a three-way cross of rabbits. Journal of Animal Breeding and Genetics, 121(3), 186-196. doi:10.1111/j.1439-0388.2004.00450.xEstany, J., Camacho, J., Baselga, M., & Blasco, A. (1992). Selection response of growth rate in rabbits for meat production. Genetics Selection Evolution, 24(6), 527. doi:10.1186/1297-9686-24-6-527García-Quirós, A., Arnau-Bonachera, A., Penadés, M., Cervera, C., Martínez-Paredes, E., Ródenas, L., … Pascual, J. J. (2014). A robust rabbit line increases leucocyte counts at weaning and reduces mortality by digestive disorder during fattening. Veterinary Immunology and Immunopathology, 161(3-4), 123-131. doi:10.1016/j.vetimm.2014.07.005Gidenne, T., & Perez, J.-M. (2000). Replacement of digestible fibre by starch in the diet of the growing rabbit. I. Effects on digestion, rate of passage and retention of nutrients. Annales de Zootechnie, 49(4), 357-368. doi:10.1051/animres:2000127Lv, J.-M., Chen, M., Qian, L.-C., Ying, H.-Z., & Liu, J.-X. (2009). Requirement of crude protein for maintenance in a new strain of laboratory rabbit. Animal Feed Science and Technology, 151(3-4), 261-267. doi:10.1016/j.anifeedsci.2009.01.001Mínguez, C., Sanchez, J. P., EL Nagar, A. G., Ragab, M., & Baselga, M. (2015). Growth traits of four maternal lines of rabbits founded on different criteria: comparisons at foundation and at last periods after selection. Journal of Animal Breeding and Genetics, 133(4), 303-315. doi:10.1111/jbg.12197Partridge, G. G., Garthwaite, P. H., & Findlay, M. (1989). Protein and energy retention by growing rabbits offered diets with increasing proportions of fibre. The Journal of Agricultural Science, 112(2), 171-178. doi:10.1017/s0021859600085063Pascual, M., & Pla, M. (2007). Changes in carcass composition and meat quality when selecting rabbits for growth rate. Meat Science, 77(4), 474-481. doi:10.1016/j.meatsci.2007.04.009Pascual, M., Pla, M., & Blasco, A. (2008). Effect of selection for growth rate on relative growth in rabbits1,2. Journal of Animal Science, 86(12), 3409-3417. doi:10.2527/jas.2008-0976Quevedo, F., Cervera, C., Blas, E., Baselga, M., & Pascual, J. J. (2006). Long-term effect of selection for litter size and feeding programme on the performance of reproductive rabbit does 2. Lactation and growing period. Animal Science, 82(5), 751-762. doi:10.1079/asc200688Sánchez, J. P., Theilgaard, P., Mínguez, C., & Baselga, M. (2008). Constitution and evaluation of a long-lived productive rabbit line1. Journal of Animal Science, 86(3), 515-525. doi:10.2527/jas.2007-0217Savietto, D., Blas, E., Cervera, C., Baselga, M., Friggens, N. C., Larsen, T., & Pascual, J. J. (2012). Digestive efficiency in rabbit does according to environment and genetic type. World Rabbit Science, 20(3). doi:10.4995/wrs.2012.1152Savietto, D., Cervera, C., Ródenas, L., Martínez-Paredes, E., Baselga, M., García-Diego, F. J., … Pascual, J. J. (2014). Different resource allocation strategies result from selection for litter size at weaning in rabbit does. Animal, 8(4), 618-628. doi:10.1017/s1751731113002437Trocino, 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.2013.1285Van 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-

Application of refrigeration for debittering table olives

During the process of making table olives, it is necessary to remove bitterness caused by phenolic compounds like oleuropein. This debittering effect is achieved by degrading these compounds into non-bitter ones that are beneficial for health due to their antioxidant properties. One of the most used methods is alkaline debittering using NaOH but the main drawback is the environmental impact generated by wastes and degradation of high-value nutraceutical compounds in olives. Different olive debittering pre-treatments followed by refrigeration storage at 5ºC during 90 days have been performed using Ocal variety olives (Olea europaea L.) by combining heat, β- glucosidase and Lactobacillus plantarum treatments. Oleuropein and hydroxytyrosol concentrations were determined in olive pulp and brine. The data has been complemented with sensory tests. The treatment with the best results was storage in refrigeration, which achieved significant debittering and greater degradation of oleuropein, due to the action of endogenous enzymes of the olives

La diversidad en la Universidad: la innovación docente para la inclusión del alumno con discapacidad auditiva en el Grado de Odontología. (Continuación)

Se plantea en el presente proyecto un sistema de adaptación de las lecciones teóricas en tres asignaturas de 3º, 4º y 5º del Grado de Odontología, al lenguaje de signos o al texto subtitulado en relación a la explicación por parte del profeso

A trial comparing growing rabbits differing in 18 generations of selection for growth rate reveals a potential lack of effectiveness in the genetic selection progress

[EN] Simple Summary There is evidence that the genetic progress in paternal rabbit lines is lower than expected due to animal- and environmental-related factors, as well as founding factors intrinsically linked to the effectiveness of the selection process. In response to this question, we conducted a trial to evaluate the response after 18 generations of selection for increased growth rate within a paternal line on rabbit performance. Our results indicate that there were no differences in the key indicators in selection for growth rate (average daily gain and feed conversion ratio) between both populations differing in the generation of selection. These findings indicate a lack of effectiveness in the genetic progress of paternal rabbit lines based on different works carried out with these same genetic lines and generations.Abstract A total of 338 weaned rabbits (from the R line, selected for post-weaning growth rate) were used to evaluate the response to 18 generations of selection for increased growth rate on rabbit performance. Animals were obtained from two vitrified populations of the R line: R19V, belonging to the 18th generation (n = 165), and R37V, belonging to the 36th generation (n = 173), were allocated in individual and collective pens (178 and 160, respectively). A fattening trial was conducted from weaning (28 d of age until 63 d of age). During the trial, the body weight (BW), daily feed intake (DFI), average daily gain (ADG) and feed conversion ratio (FCR) were weekly monitored. Additionally, mortality and morbidity were daily registered. On days 49 to 53, an apparent faecal digestibility trial was also performed (12 animals per generation). Our results indicate that the generation of selection for growth rate did not affect mortality and morbidity. There were no differences in the diet digestibility according to the generation of selection. Regarding performance traits, R37V animals showed higher global BW (+6.7%; p = 0.0011) than R19V animals. R37V animals showed the same BW at weaning; however, R37V animals showed higher BW values in the last three weeks compared with R19V animals. Animals from the R37V generation also showed a higher DFI from 56 to 63 d of age (+12%; p = 0.0152) than R19V animals. However, there were no differences in global ADG and FCR between generations. These results indicate that the selection for growth rate in growing rabbits has slowed down, suggesting a lack of effectiveness in the genetic progress.We are grateful to the Veterinary Medicine Faculty of Universidad Cardenal Herrera-CEU.Marín-García, PJ.; Martinez-Paredes, E.; Ródenas Martínez, L.; Llobat, L.; Cambra López, M.; Blas Ferrer, E.; Pascual Amorós, JJ. (2023). A trial comparing growing rabbits differing in 18 generations of selection for growth rate reveals a potential lack of effectiveness in the genetic selection progress. Animals. 13(12):1-11. https://doi.org/10.3390/ani13233625111131

Expression of Inducible Nitric Oxide Synthase (iNOS) in Microglia of the Developing Quail Retina

Inducible nitric oxide synthase (iNOS), which produce large amounts of nitric oxide (NO), is induced in macrophages and microglia in response to inflammatory mediators such as LPS and cytokines. Although iNOS is mainly expressed by microglia that become activated in different pathological and experimental situations, it was recently reported that undifferentiated amoeboid microglia can also express iNOS during normal development. The aim of this study was to investigate the pattern of iNOS expression in microglial cells during normal development and after their activation with LPS by using the quail retina as model. iNOS expression was analyzed by iNOS immunolabeling, western-blot, and RT-PCR. NO production was determined by using DAR-4M AM, a reliable fluorescent indicator of subcellular NO production by iNOS. Embryonic, postnatal, and adult in situ quail retinas were used to analyze the pattern of iNOS expression in microglial cells during normal development. iNOS expression and NO production in LPS-treated microglial cells were investigated by an in vitro approach based on organotypic cultures of E8 retinas, in which microglial cell behavior is similar to that of the in situ retina, as previously demonstrated in our laboratory. We show here that amoeboid microglia in the quail retina express iNOS during normal development. This expression is stronger in microglial cells migrating tangentially in the vitreal part of the retina and is downregulated, albeit maintained, when microglia differentiate and become ramified. LPS treatment of retina explants also induces changes in the morphology of amoeboid microglia compatible with their activation, increasing their lysosomal compartment and upregulating iNOS expression with a concomitant production of NO. Taken together, our findings demonstrate that immature microglial cells express iNOS during normal development, suggesting a certain degree of activation. Furthermore, LPS treatment induces overactivation of amoeboid microglia, resulting in a significant iNOS upregulation.This work was supported by grants from Ministerio de Economía y Competitividad, Spain (BFU2010-19981) and Junta de Andalucía, Spain (P07-CVI-03008)

Unravelling the Role of Metabolites for Detecting Physiological State of Wild Animals: European Rabbit's (Oryctolagus cuniculus) Case

[EN] The main aim of this work was to know the possible potential of certain metabolites as biomarkers of the European wild rabbit to deepen the biological knowledge of this species and complement specific conservation programs. The main finding of our paper is that, regardless of the weight of the animals and their reproductive state, females show greater feed intake capacity than males, and their metabolism is affected. Furthermore, different reproductive stages are related to different metabolic phenotypes, metabolic behaviors, and metabolic profiles. There are indications of better optimization of resources by females, and evidence of the importance of some metabolites in the reproductive fitness of the species. European wild rabbit (Oryctolagus cuniculus) has been defined as a keystone species in the Mediterranean ecosystem. Rabbits have been classed as "endangered" by the IUCN within their native range. In this sense, animal nutrition may play a fundamental and limiting role in the conservation of wild species. The overarching goal of ecological nutrition is to unravel the extensive web of nutritional links that direct animals in their interactions with their ecological environments. The main aim of this work was to evaluate the effect of different feed intake, geographic location, animal sex, and reproductive stage on glucose, non-esterified fatty acids (NEFA), and plasmatic urea nitrogen (PUN), albumin, glutamate, and total protein metabolites. Additionally, we examined the potential of these metabolites as biomarkers. Full stomach contents and blood samples were collected from European wild rabbits (n = 89) for the analysis of the metabolites described above. Our work shows that the levels of these metabolites are affected by the sex of the animals, as well as by their reproductive stage (glucose, NEFA and albumin). There were signs of better optimisation of resources by females than by other groups of animals. These data may be interesting in the study of nutritional components that could be affecting physiological state of this species.This study was supported by the Regional Ministry of Innovation, Universities, Scienceand Digital Society of the Generalitat Valenciana (GV/2021/115 and CIBEST/2021/157) and Universidad Cardenal Herrera CEU (PUENTE22-03). This study was partially supported by a project granted by the Partnership for Research and Innovation in the Mediterranean Area (PRIMA) and funded by the Spanish Ministry of Science, Innovation and University (REF: PRIMAS2-11-PCI2019-103698). The APC was invited to Pablo Jesus Marin Garcia.Marín-García, PJ.; Llobat, L.; Rouco, C.; Aguayo-Adán, JA.; Larsen, T.; Cambra López, M.; Blas Ferrer, E.... (2022). Unravelling the Role of Metabolites for Detecting Physiological State of Wild Animals: European Rabbit's (Oryctolagus cuniculus) Case. Animals. 12(22):1-9. https://doi.org/10.3390/ani1222322519122

The nutritional strategy of European rabbits is affected by age and sex: Females eat more and have better nutrient optimisation

[EN] The ecological interest in the European rabbit (Oryctolagus cuniculus) has grown since it was declared an endangered species. Nutrition is fundamental in its dispersion and the key to its success. This is the main reason why knowledge of their nutritional preferences/requirements could play a fundamental role in rabbit biology and, therefore, in their conservation. The objectives of the work will be to elucidate how age and sex affect both nutritional preferences/requirements, and the nutrient optimisation of European rabbits. To address this gap, 70 wild European rabbits were studied. The rabbits were divided according to their age: adult (n = 43) and young (n = 27). Two groups were differentiated according to the adult rabbits' sex: females (n = 28) and males (n = 15). We analysed the relative (%) and absolute (g) chemical composition of the rabbits' gastric contents: dry matter (DM), ashes (ASH), crude protein (CP), ether extract (EE), neutral detergent fibre (NDF), acid detergent fibre (ADF), and lignin, hemicelluloses and celluloses, highly digestible nonnitrogenous nutrients (HDNN: fat, starch, and soluble fibre), well from the blood was analysed with plasmatic urea nitrogen (PUN), nonesterified fatty acid (NEFA) and glucose (GLU). As a nutrient optimisation measure, the following indices between blood metabolites and stomach content were calculated: PUN/CP total content, NEFA/DM total content and GLU/DM total content ratios. Our works showed that age and sex affected the nutritional strategy of rabbits. Regarding age: adults showed lower CP (-14%; p = 0.0217) and higher HDNN (+21%; p = 0.0399) relative content than young rabbits, and absolute amount of most nutrients: DM (+59%; p = 0.001), OM (+43%; p = 0.0049), ASH (+54%; p = 0.0085), Hemicelluloses (+73%; p = 0.0084), Cellulose (+27%; p = 0.0452), and HDNN (+63%; p = 0.0012). In addition, adults showed better nutrient optimisation. Sex did not affect the relative chemical composition of the gastric content, but it showed a clear higher gastric content by females (+85%; p < 0.0001) and higher intake of most of the absolute chemical components: DM (+64%; p < 0.001), CP (+56%; p = 0.0005), OM (+58%; p = 0.0001), ASH (+44%; p = 0.0123), HDNN (+39%; p = 0.001), NDF (+59%; p = 0.001), ADF (+64%; p = 0.0003), lignin (+82%; p = 0.0036) and cellulose (+58%; p = 0.0002). Finally, we observed that females had better nutrient optimisation than males. This works supports the idea that feeding ecology and nutrition are particularly relevant to reproductive success and fitness in wild animals.Universidad Cardenal Herrera-CEU, Grant/Award Number: PUENTE22/03; Regional Ministry of Innovation, Universities, Science and Digital Society of the Generalitat Valenciana, Grant/Award Numbers: GV/2021/115, CIBEST/2021/157Marín-García, PJ.; Llobat, L.; Aguayo-Adán, JA.; Larsen, T.; Cambra López, M.; Blas Ferrer, E.; Pascual Amorós, JJ.... (2023). The nutritional strategy of European rabbits is affected by age and sex: Females eat more and have better nutrient optimisation. Journal of Animal Physiology and Animal Nutrition. 107(5):1294-1301. https://doi.org/10.1111/jpn.1382612941301107

Nutritional ecology of European rabbit (Oryctolagus cuniculus): Factors affecting chemical composition of gastric content

[EN] Nutritional ecology seeks to unravel the extensive web of nutritional links that directs animals in their interactions with their ecological and social environments. European rabbit (Oryctolagus cuniculus) populations its endemic locations are declining and it is considered a keystone species of the Mediterranean ecosystem prompteing the interest in its conservation. The main aim of this study was to determine the nutritional composition of the diet of European rabbits through the relative and absolute chemical composition of the gastric content. To address this objective, gastric content was collected from 80 European rabbits in a Mediterranean area for the analysis of its chemical composition. To this end, gastric content was analyzed for dry matter (DM), organic matter (OM), ash, crude protein (CP), highly digestible nonnitrogenous nutrients (HDNN), neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin. The rabbits were divided into two groups: EMPTY and FULL, depending on the level of stomach filling, directly related to food intake. Our results revealed a positive correlation between the rabbits weight with DM in the gastric content, total gastric content with DM in the gastric content, and DM in gastric content with all chemical parameters analysed. The mean relative values obtained were 8.8%, 25.5%, 40.4% and 25.4%, for ash, CP, NDF and HDNN, respectively. Moreover, EMPTY rabbits had both a proportional (+19%, p = 0.002 and -40%; p = 0.004, on NDF and HDNN, respectively) and absolute (-38%, p = 0.014, -52%; p = 0.012, -52%; p = 0.011 and +83%; p = 0.008 for OM, ash, HDNN, and lignin, respectively) different proportion of nutrients in gastric contents than FULL animals. Since there is a connection between this availability and the fitness of this species, understanding the chemical composition of the rabbit's diet can be utilised to delve into its biology. Our study provides information that will help elucidate the factors affecting the chemical composition of the gastric content of European rabbits to assist land use planners and conservationists in identifying sites for conservation in Mediterranean ecosystems.Regional Ministry of Innovation, Universities, Science and Digital Society of the Generalitat Valenciana, Grant/Award Number: GV/2021/115Marín-García, PJ.; Llobat, L.; Aguayo-Adán, JA.; Franch, J.; Cambra López, M.; Blas Ferrer, E.; Pascual Amorós, JJ.... (2023). Nutritional ecology of European rabbit (Oryctolagus cuniculus): Factors affecting chemical composition of gastric content. Journal of Animal Physiology and Animal Nutrition. 107(6):1495-1501. https://doi.org/10.1111/jpn.1384914951501107

Do Growing Rabbits with a High Growth Rate Require Diets with High Levels of Essential Amino Acids? A Choice-Feeding Trial

[EN] Two diets were designed to investigate the effect of the growth rate on amino acid requirements in growing rabbits: M diet (with medium levels of amino acids, following current nutritional recommendations for growing rabbits) and H diet (with high levels of lysine, sulphur amino acids and threonine compared with current nutritional recommendations). Performance, nutrient retention and digestibility (faecal and ileal) trials, as well as a choice-feeding test were conducted. We found no differences in animal performance, nutrient retention and digestibility parameters between diets, but the animals showed a preference for the M diet, expressed by a high intra-individual repeatability in preference. Our results provide useful information and nutrition tools to move towards precision protein nutrition in growing rabbits. As a consequence of the genetic selection process in growing rabbits, there are currently fast-growing animals exhibiting an average daily gain that may exceed 45 g/d. The protein requirements of these animals, namely amino acid requirements, may differ from animals with low growth rates. The objective of this work was to evaluate growth performance, the coefficient of total tract apparent digestibility (CTTAD), the apparent ileal digestibility (AID) of amino acids and nutrient retention of fast-growing rabbits when they had access to a diet with high levels of amino acids and/or a diet formulated with current nutritional recommendations in a choice-feeding trial. To this end, two diets were formulated: the M diet following current nutritional recommendations for growing rabbits (including 8.1, 5.8 and 6.9 g/kg dry matter (DM) of total lysine, sulphur amino acids and threonine, respectively) and the H diet with higher levels of total lysine, sulphur amino acids and threonine (9.4, 6.6 and 7.8 g/kg DM, respectively). A total of 220 weaned rabbits, from a paternal line selected for the growth rate, had free access to the M diet, the H diet or both (MH) diets from 28 to 63 days of age. The CTTAD of DM, crude protein and gross energy from 49 to 53 days of age as well as the AID of amino acids of the diets at 63 days of age were determined. Protein, amino acids and energy retained in the empty body from 28 to 63 days of age were also registered. No significant differences in growth performance, CTTAD, AID and nutrient retention between dietary treatments were observed. However, animals fed the H diet showed a higher AID of cysteine (p < 0.05) and higher threonine retention (p < 0.05) compared to the M diet. As regards the choice-feeding trial, MH animals showed a higher feed intake of the M diet compared to the H diet (+8.61%; p < 0.001), and furthermore, more than 50% of the animals preferred the M diet throughout the experimental period (p < 0.05). Our results suggest that animals with high growth rates do not show significantly higher productive traits when fed the H diet compared to the M diet. As regards choice feeding, MH animals were capable of choosing their preferred diet, showing high intra-individual repeatability in preference for the M diet. It would be interesting to continue studying this behaviour of choice based on amino acid levels.This research was funded by the Interministerial Commission for Science and Technology (CICYT; grant no. AGL2017-85162-C2-1-R).Marín-García, PJ.; López Luján, MDC.; Ródenas Martínez, L.; Martinez-Paredes, E.; Cambra López, M.; Blas Ferrer, E.; Pascual Amorós, JJ. (2021). Do Growing Rabbits with a High Growth Rate Require Diets with High Levels of Essential Amino Acids? A Choice-Feeding Trial. Animals. 11(3):1-13. https://doi.org/10.3390/ani11030824S11311