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Wheat and potato are rich in starch but their starches differ in their rate of ruminal degradation. Kinetics of in sacco disappearance and profiles of ruminal fermentation were studied for these two concentrates in total mixed rations based on grass silage or corn silage. Wheat starch was more rapidly (34%/h) degraded by rumen microorganisms than potato starch (5%/h). The differences in starch degradation in sacco were found again in the VFA concentrations, mainly in grass silage-based diets. Overall ruminal pH, total VFA concentration, and proportions of acetate, propionate, and butyrate are more variable for wheat during the kinetic (amplitude and quickness) than for potato in grass silage-based diets. In these diets, risks of acidosis were more elevated with wheat than with potato but the VFA concentrations were also higher. These differences of fermentation profile were so reduced in corn silage-based diets that, in this case, wheat can be substituted by potato without any effect on digestion and no risk of acidosis. Key Words: Kinetics, Potatoes, Rumen, Starch, Wheat

The aim of this study was to predict the beef carcass and LM (thoracis part) characteristics and the sensory properties of the LM from rearing factors applied during the fattening period. Individual data from 995 animals (688 young bulls and 307 cull cows) in 15 experiments were used to establish prediction models. The data concerned rearing factors (13 variables), carcass characteristics (5 variables), LM characteristics (2 variables), and LM sensory properties (3 variables). In this study, 8 prediction models were established: dressing percentage and the proportions of fat tissue and muscle in the carcass to characterize the beef carcass; cross-sectional area of fibers (mean fiber area) and isocitrate dehydrogenase activity to characterize the LM; and, finally, overall tenderness, juiciness, and flavor intensity scores to characterize the LM sensory properties. A random effect was considered in each model: the breed for the prediction models for the carcass and LM characteristics and the trained taste panel for the prediction of the meat sensory properties. To evaluate the quality of prediction models, 3 criteria were measured: robustness, accuracy, and precision. The model was robust when the root mean square errors of prediction of calibration and validation sub-data sets were near to one another. Except for the mean fiber area model, the obtained predicted models were robust. The prediction models were considered to have a high accuracy when the mean prediction error (MPE) was ≤0.10 and to have a high precision when the r2 was the closest to 1. The prediction of the characteristics of the carcass from the rearing factors had a high precision (r2 > 0.70) and a high prediction accuracy (MPE < 0.10), except for the fat percentage model (r2 = 0.67, MPE = 0.16). However, the predictions of the LM characteristics and LM sensory properties from the rearing factors were not sufficiently precise (r2 < 0.50) and accurate (MPE > 0.10). Only the flavor intensity of the beef score could be satisfactorily predicted from the rearing factors with high precision (r2 = 0.72) and accuracy (MPE = 0.10). All the prediction models displayed different effects of the rearing factors according to animal categories (young bulls or cull cows). In consequence, these prediction models display the necessary adaption of rearing factors during the fattening period according to animal categories to optimize the carcass traits according to animal categories. [ABSTRACT FROM AUTHOR]

Dietary change alters the ruminai ecosystem and can be regarded as a disturbance. Studying the response to a disturbance can help us understand the behavior of the ecosystem. Our work is concerned with the response of the ruminai ecosystem (composition and activities) during the application of repeated dietary disturbances to 6 dry Holstein cows. For 2 mo, the cows received a hay-based diet [experimental period (EP) 0], followed by 3 EP of successive changes (EP 1,2, and 3) comprised of 2 parts: the first (10 d) with a corn silage-based diet and the second (25 d) with a hay-based diet. The measurements and samplings were done on the last days of EP 0 and of each part of EP 1 through 3, with the results of EP 0 used as covariables in the statistical models. The physicochemical measurements (pH and redox potential) and the fermentation variables (VFA, ammonia) were determined hourly between the morning and evening meals (n = 8 measurements/d). Samples of ruminai contents were taken 3 h after the morning meal to determine enzymatic activity [amylase, carboxy-methyl cellulase (CMCase), and xylanase], to count the main protozoan genera and to quantify the bacteria by quantitative PCR, and to determine its structure by the capillary electrophoresis single-strand conformation polymorphism process. The pH fell for the corn silage-based diet with the EP (P < 0.05) but not for the hay-based diet. The VFA concentration decreased for both diets with the EP (P < 0.001), with the primary changes in acetate and propionate. The ammonia concentration increased for the corn silage-based diet with the EP (P < 0.05), whereas for the hay-based diet the highest value was observed for EP 2 (P < 0.05). The total quantity of bacteria decreased between EP 1 and 3 (P < 0.05) for both diets. The structure of the bacterial community was not affected by the disturbances for the corn silage-based diet, whereas for the hay-based diet large differences were evident between EP 1 and 3 (P < 0.05) and 2 and 3 (P < 0.01). The number of protozoa increased over the EP, with a more marked effect for the corn silage-based diet (diet x EP interaction, P < 0.05). The specific amylase, CMCase, and xylanase activities decreased over the EP for both diets (P < 0.05). The dietary changes applied in our experiment involved strong modifications of the ruminai ecosystem and alterations of ruminai fermentation and enzymatic activities. These alterations were reinforced with the repetition of the dietary changes. [ABSTRACT FROM AUTHOR]

This work aimed to study the changes over time in the bacterial communities associated with the fluid and food particle fractions of the cow rumen following a change in diet. Four cannulated cows were fed a hay-based diet for 21 days and were then switched to a corn-silage-based diet for 33 days. The bacterial communities were regularly characterized by capillary electrophoresis - single-strand conformation polymorphism (CE-SSCP) and qPCR, and the main ruminal parameters were determined. The dietary change led to slight reductions in the diversity index, bacterial concentration, pH, and NH3-N concentration, and to an increase in the redox potential and volatile fatty acid concentrations. CE-SSCP profiles were not significantly affected by the dietary change but did change over time, with frequent fluctuations in both fluid and food particle fractions before and after the dietary change. The food particle fraction had a higher diversity index of bacterial community (+1.2 points, P < 0.001) and slightly more total bacteria than the fluid fraction of the rumen. [ABSTRACT FROM AUTHOR]

Presents a study which compared wheat and potato peelings in sacco disappearance kinetics, with emphasis on the starch fraction and the change of fermentation kinetics. Composition of the different diets and their nutritive values; Use of the nylon bag technique to measure disappearance rates; Profiles of ruminal fermentation; Results and discussion.

The aims of this study were, analysing the effects of rearing managements, carcass traits, and muscle type (M. complexus [CP], M. infraspinatus [IF], M. longissimus [LM], M. rhomboideus [RH], and M. serratus ventralis [SV]) on toughness of raw meat; developing prediction models to act on their toughness. According to our results obtained on the data of 77 heifers, the IF raw muscle was the toughest and appeared the most sensitive to a change in the rearing management. The four other raw muscles had a similar toughness within heifers from the same rearing management. The five raw muscles were less tough when the carcass was heavier and had higher dressing percentage and conformation. The 3 models explained about 40% of the variability observed. Our models showed that it is possible to improve the potential tenderness of raw meat, acting on: age of the heifer's mother, growth rate during the growth and fattening periods, slaughter age, carcass weight and temperature 24 h post-mortem. • The toughness of 5 rib's raw muscles was analysed by warner-bratzler shear force. • The effects of rearing managements applied during the whole life of heifers, carcass traits, and muscle type on the toughness of the 5 rib's raw muscles were analysed. • Infraspinatus raw muscle was the toughest and appeared the most sensitive to a change in the rearing management. • Age of the heifer's mother, growth rate during the growth and fattening periods, slaughter age, carcass weight and temperature at 24 h post-mortem are factors impacting the potential tenderness of raw meat. [ABSTRACT FROM AUTHOR]

Abstract: Live yeast Saccharomyces cerevisiae NCYC Sc 47 was added to the diet of weaning rabbits (35d old) to analyse the effects on the caecal ecosystem (biotope and bacterial community), digestion and health status. Two levels of yeast (1 and 10g/kg feed, group C1 and C10 corresponding to 106 and 107 CFU/g DM) were compared to a control group (C0) without live yeast addition. Three groups of 10 young rabbits were used in a first experiment to measure digestibility and caecal parameters and to calculate the yeast survival rate in the digestive tract. Growth performance and health status were studied on 3 further groups of 40 rabbits (Experiment 2). The live yeast concentration fell slightly after diet pelleting (0.1–0.5logCFU/gDM), at 70–80°C. The survival rate of yeast in digestive tract was high and increased from 90 to 97% (P<0.01) with increasing yeast supplementation. Live yeast addition did not modify the total tract digestibility of nutrients, or the growth performance. Mortality rate between 42 and 56d of age was lower at the highest yeast level (C10: 4 dead on 40; P<0.05) compared to C0 and C1 groups (average 13/40),. The structure of the caecal bacterial community was not modified after 11d of yeast presence in the caecum, while the bacterial diversity tended to be higher (5.0 vs 5.4, P=0.10, for C0 vs [C1+C10]). The redox potential of the caecal content increased with yeast addition (−227 vs −251mV, P<0.05 for C0 vs [C1+C10]), whereas the fermentation pattern and the caecal pH remain unaffected (meanly 5.88). [Copyright &y& Elsevier]

The aim of this study was to analyse simultaneously the effect of rearing managements (RM), carcass traits, muscle type (longissimus thoracis , LT and rectus abdominis , RA) and their interactions on colour (system L*a*b*), sensory and rheological properties of 77 heifers. The data used were 46 rearing factors defining four RM applied during the heifers' whole life from and 5 carcass traits discriminating two carcass quality clusters (Low and High quality). The results showed that the RM had an impact on the carcass and meat quality traits. The redness and the overall acceptability of LT meat were more sensitive to variation of RM than RA meat. The tenderness of LT and RA were similar or not according to the RM. Higher tenderness was obtained from high carcass quality irrespective the muscle. These results show that similar carcass and meat qualities can be obtained with different RM. They also demonstrated that it is also possible to manage jointly carcass and meat qualities. [ABSTRACT FROM AUTHOR]

In this study, four prediction models were developed by logistic regression using individual data from 96 heifers. Carcass and sensory rectus abdominis quality clusters were identified then predicted using the rearing factors data. The obtained models from rearing factors applied during the fattening period were compared to those characterising the heifers' whole life. The highest prediction power of carcass and meat quality clusters were obtained from the models considering the whole life, with success rates of 62.8% and 54.9%, respectively. Rearing factors applied during both pre-weaning and fattening periods influenced carcass and meat quality. According to models, carcass traits were improved when heifer's mother was older for first calving, calves ingested concentrates during pasture preceding weaning and heifers were slaughtered older. Meat traits were improved by the genetic of heifers' parents ( i.e. , calving ease and early muscularity) and when heifers were slaughtered older. A management of carcass and meat quality traits is possible at different periods of the heifers' life. [ABSTRACT FROM AUTHOR]

This study characterized, for the first time, the rearing managements (from birth to slaughter) applied throughout the cull cows' life and observed the effect of these managements on the carcass and meat properties. From the individual data of 371 Charolais cull cows, three rearing managements were defined and characterized with 60 rearing factors. The results showed that the rearing managements had low effects on the carcass and meat properties. For the carcass traits, only the carcass weight, and fat and longissimus (LM) colors at the level of the sixth rib were impacted. Concerning the meat, only the red color intensity, the fat aroma, the flavor intensity and persistence were affected. According to our results, this study confirmed that it is possible to produce carcass or meat with similar properties; consequently, it is difficult to favor a rearing management. However, to manage jointly both carcass and meat qualities, trade-offs are needed.

The aim of this work was to study, for the first time, the effects of the rearing management (from birth to slaughter) applied throughout the life of young bulls on carcass and meat quality. Five rearing managements were defined statistically, from a combination of 30 rearing factors, using a hierarchical clustering on principal components. This study considered the individual data of 179 Charolais young bulls from commercial farms. The carcass traits were more sensitive to rearing management than the meat traits. Rearing management had an effect mainly on fat and overall meat grain for the carcass, and on color and tenderness for the longissimus meat. However, it was possible to produce carcass and/or meat with similar properties from different rearing managements. Among the five rearing managements defined in this study, two were identified as allowing the best trade-off to produce simultaneously high carcass and meat quality. The first management was characterized by absence of growth period and a short fattening duration, with a wrapped haylage or corn silage-based diet. The second management was characterized by short pre-weaning and growth periods, and a long fattening period.

The study aim was to identify the effects of the rearing management applied throughout the heifers' life on the carcass (e.g., conformation, marbling, fat) and meat (color, texture, and sensory profiles) properties. From the individual data of 171 heifers from 25 commercial farms, a typology of four rearing managements was established from 50 rearing factors. The managements had an effect on the conformation, the color (fat and muscle), and the rhomboideus grain meat, for the carcass, and the lightness, the atypical flavor, and the overall acceptability for the longissimus (LM) meat. The carcass traits compared to the meat were more sensitive to a change of rearing management. Our results confirmed that it was possible to target the same carcass or meat quality from different managements. Moreover, according to the aims of the targeted carcass and LM meat quality, management 3 could be an interesting trade-off to jointly manage the quality of both products. For example, the carcasses that were produced had a high conformation, smooth meat grain and the LM meat was more liked. This management was intermediate compared to the other rearing managements and had a long fattening period with a diet mainly based on conserved grass and a high concentrate quantity.

This paper presents data of rearing practices collected by survey from 45 beef heifers breeders. All the breeders were members of 'Génisse Fleur d'Aubrac' protected geographical indication (PGI). The surveys were conducted face-to-face using a questionnaire which addressed the rearing practices applied throughout the animals' life. The animals' life was considered in 3 periods: suckling, growth and fattening periods. The rearing practices (n=105) addressed a wide range such as the dietary compositions in stall and on pasture, the duration of each life period and the age of heifers at each change, the prophylactic treatments, the birth and slaughter dates. Both quantitative and qualitative variables were used to characterise the management system. The parameters (n=7) of the carcasses produced (n=636) in these farms were collected from the only slaughterhouse of the PGI., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this article., (© 2022 The Author(s). Published by Elsevier Inc.)

Meat quality prediction is a priority for the beef industry. Label free shotgun proteomics was performed on Longissimus muscle and plasma from 20 crossbred Charolais x Aubrac beef heifers, classified as subgroups of 5 extreme tender and 5 extreme tough meat according to sensory evaluation, Warner Bratzler shear force, and a synthetic tenderness index. This technique identified 268 proteins in muscle and 136 in plasma. Among them, 71 muscle proteins and 21 plasma proteins discriminated tender and tough groups. These proteins were analyzed to select the most correlated and explicative ones which were used in a linear regression on the 20 heifers. The results validated in heifers 33 muscle proteins previously identified as related with tenderness, and revealed 38 new candidates. Twelve are localized in shear force or tenderness score QTL. Among them ACTN2, ADSSL1, GOT1, HPX, OGDH, OGN, TNNC1 and VCL are proposed as robust candidates with 3 other proteins known to be related with tenderness (MYBPH, CAPZB, MYH1). Examination of the plasma proteome showed 8 putative biomarkers (MYH7, CFH, ENO3, PLA2G2D5, FHL1, GAPDH, MASP2 and SERPINF2). Three of them (MYH7, ENO3 and FHL1) were identified as discriminative of tenderness both in Longissimus muscle and in plasma. SIGNIFICANCE: The label free proteomic approach used in this study allowed to complete the atlas of biomarkers for tenderness of the Longissimus muscle. This innovative proteomic approach applied on plasma samples allowed to identify circulating candidate biomarkers for beef tenderness. This low-invasive approach constitutes an interesting alternative to evaluate early the "beef meat potential" of living animals in farm or of the carcass in slaughterhouses., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2020. Published by Elsevier B.V.)

This trial aimed to integrate metadata that spread over farm-to-fork continuum of 110 Protected Designation of Origin (PDO)Maine-Anjou cows and combine two statistical approaches that are chemometrics and supervised learning; to identify the potential predictors of beef tenderness analyzed using the instrumental Warner-Bratzler Shear force (WBSF). Accordingly, 60 variables including WBSF and belonging to 4 levels of the continuum that are farm-slaughterhouse-muscle-meat were analyzed by Partial Least Squares (PLS) and three decision tree methods (C&RT: classification and regression tree; QUEST: quick, unbiased, efficient regression tree and CHAID: Chi-squared Automatic Interaction Detection) to select the driving factors of beef tenderness and propose predictive decision tools. The former method retained 24 variables from 59 to explain 75% of WBSF. Among the 24 variables, six were from farm level, four from slaughterhouse level, 11 were from muscle level which are mostly protein biomarkers, and three were from meat level. The decision trees applied on the variables retained by the PLS model, allowed identifying three WBSF classes (Tender (WBSF ≤ 40 N/cm 2 ), Medium (40 N/cm 2 < WBSF < 45 N/cm 2 ), and Tough (WBSF ≥ 45 N/cm 2 )) using CHAID as the best decision tree method. The resultant model yielded an overall predictive accuracy of 69.4% by five splitting variables (total collagen, µ-calpain, fiber area, age of weaning and ultimate pH). Therefore, two decision model rules allow achieving tender meat on PDO Maine-Anjou cows: (i) IF (total collagen < 3.6 μg OH-proline/mg) AND (µ-calpain ≥ 169 arbitrary units (AU)) AND (ultimate pH < 5.55) THEN meat was very tender (mean WBSF values = 36.2 N/cm 2 , n = 12); or (ii) IF (total collagen < 3.6 μg OH-proline/mg) AND (µ-calpain < 169 AU) AND (age of weaning < 7.75 months) AND (fiber area < 3100 µm 2 ) THEN meat was tender (mean WBSF values = 39.4 N/cm 2 , n = 30).

Background: This study implemented a holistic approach based on the farm-to-fork data at the four levels of the continuum (farm - slaughterhouse - muscle - meat) to study the inter-individual cluster variability of beef tenderness. For that, 171 young bulls were selected on a large database of 480 animals according to the industrial expectations based on animal and carcass characteristics. The targeted factors were age at slaughter (14; 20 months), carcass weight (370; 470 kg), EUROP conformation (7; 15) and fatness (2.5; 5) scores of the carcasses. Multivariate analyses and unsupervised learning tools were performed., Results: Principal component analysis combined to agglomerative hierarchical clustering allowed ten clusters to be identified that differed (P < 0.0001) for the four targeted factors. The clusters were further different for variables belonging to each level of the continuum. The results indicated an inter-individual cluster variability rising in tenderness in link with the continuum data grouped according to industrial expectations. The associations of the whole variables of the continuum with tenderness were very important, but farm-to-fork continuum-levels dependent. The findings showed that the variables contributing most to the inter-individual cluster variability of tenderness seemed to be more related to the rearing practices, mainly feeding, and their consequences on carcass properties rather than to the muscle characteristics evaluated by enzyme metabolism and connective tissue., Conclusion: It seems that considering the continuum data would allow possible trade-off managements of tenderness to identify levers at different levels from the farm-to-meat. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

The aim of this work was to study the effects of four different rearing managements applied during the heifers' whole life period (WLP) on muscles from ribs in the chuck sale section. The characteristics of meat studied were the sensory, rheological, and color of the longissimus muscle (LM) and the rheological traits of four other muscles: complexus, infraspinatus, rhomboideus, and serratus ventralis. The main results showed that WLP rearing managements did not significantly impact the tenderness (sensory or rheological analyses) of the rib muscles. The LM had high ( p ≤ 0.05) typical flavor and was appreciated when heifers received a WLP rearing management characterized by a short pasture duration during the heifers' whole life (WLP-E). The heifers' management characterized by a long pasture duration during their life (WLP-A) or by a diet composed mainly of hay during the growth and fattening periods (WLP-F), had lower typical flavor and were less appreciated than those with WLP-E management. Moreover, the LM color was redder for heifers of WLP-E than those of the WLP-A and WLP-F groups. This study confirmed that it is possible to obtain similar meat qualities with different rearing managements.

Background: The present study explored the potential use of decision trees on rearing factors (q = 10) and carcass characteristics (q = 12) for the development of prediction model rules of beef tenderness prediction/categorization. Accordingly, 308 young bulls were used by a sensory panel to evaluate the tenderness potential of ribeye steaks grilled at 55 °C. A classification and regression tree method was implemented and allowed the prediction of tenderness using (i) rearing factors, (ii) carcass characteristics or (iii) both., Results: The resultant tree models yielded predictive accuracies of 70.78% (with four rearing factors: concentrate percentage; fattening duration; initial body weight and dry matter intake); 67.21% (with four carcass characteristics: fatness carcass score; carcass weight; dressing percentage and muscle carcass percentage) and 84.41% (with six rearing factors and carcass characteristics) compared to the k-means clustering of tenderness. In the final and robust regression tree, from the 22 attribute information, two carcass characteristics (fatness carcass score and muscle carcass percentage) and four rearing factors (fattening duration; concentrate percentage; dry matter intake and initial body weight) were retained as predictors. The first splitter of the 308 ribeye steaks in accordance with their tenderness scores was fatness carcass score, followed by fattening duration and concentrate percentage., Conclusion: The trial in the preset study highlights the importance of thresholding approach for efficiently classifying ribeye steaks in accordance with their tenderness potential. The overall prediction model rule was: IF (fatness carcass score ≥ 2.88) AND (concentrate ≥ 82%) [AND (muscle carcass ≥ 71%)] THEN meat was [very] tender. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

This study is based on an integromic approach of 71 young bulls' data from the farmgate-to-meat continuum including omics-based biomarkers, to understand beef tenderness variability in two muscle cuts that differ by their contractile and metabolic properties. By the means of chemometrics using partial least-squares (PLS) and principal component regressions (PCR), important variables from a list of 49 that characterize four levels of the continuum (rearing factors-carcass-muscle-meat) were identified to explain tenderness of Longissimus thoracis (LT) and Semitendinosus (ST) muscles evaluated by a sensory panel and instrumental Warner-Bratzler shear force (WBSF). The PLS and PCR analyses validated 16 and 15 variables for LT and 12 and 14 for ST from the whole continuum to explain sensory tenderness and WBSF, respectively. Among the explanatory variables in the four models and in line with the role of apoptosis in tenderness determinism, HSP70-1A/B (a heat shock protein) was retained to explain beef tenderness irrespective of muscle and evaluation method. Similarly, dressing percentage from the carcass level was another robust predictor but in a muscle-dependent direction manner. HSP20, ENO3, and MyHC-I as three muscle protein biomarkers and dry matter intake (DMI) as a rearing factor were involved in three models to explain beef tenderness. This study highlighted also that several variables were muscle-specific irrespective of the evaluation method of tenderness. For LT muscle, six variables including three carcass traits (fatness score, fat carcass %, and muscle carcass %), two muscle biomarkers (HSP70-8 and MyHC-IIx/b), and one meat quality trait (pH 3h ) were found. For ST muscle, five variables were validated from two rearing factors (average daily gain and feed efficiency) and three structural protein biomarkers (α-actin, MyBP-H, and CapZ-β). Finally, for WBSF only, lactate dehydrogenase chain B (LDH-B) was retained positively for LT and negatively for ST muscles. Overall, this trial showed that tenderness of LT and ST muscle cuts is influenced by variables belonging to the whole continuum with relationships that depend on both the muscle type and the evaluation method. It further highlighted the potential of integromic/chemometric approaches on the farmgate-to-meat continuum data to better understand the sophisticated biological processes that orchestrate the conversion of muscle into meat and tenderness determinism.

The aim of this study was to investigate the impact of rearing managements applied during a heifers' whole life on the carcass and flank steak (rectus abdominis) meat traits. For this study, rearing managements applied on 96 heifers were identified by conducting surveys in farms. A heifers' whole life was divided into three key periods: Pre-weaning, growth, and fattening. The combination of the rearing factors applied during the heifers' whole life allowed us to characterize several rearing managements. Among them, four have been studied in depth. The main results displayed that the carcass traits were more sensitive to the rearing managements than the flank steak traits. The different managements considered had an impact on the weight, the dressing percentage and the conformation score of the carcass. Whereas, they had no impact on the sensory descriptors, the sheer force and the color of the flank steak. This study showed that the variations observed for carcass and meat traits could not be explained by the variation of only one rearing factor but could be explained by many rearing factors characterizing the rearing management applied. Finally, this study demonstrated that it was possible to improve carcass traits without deteriorating meat traits., Competing Interests: The author declares no conflicts of interest.

This study investigated the effects of animal, carcass and muscle characteristics on initial color traits of steaks from 887 Charolais cattle. First, the fixed factors of year of birth, experiment and sex had strong impacts on color traits. From the covariates, increased age lead to intense color (low h*, -1.55 units) and darker and vivid meat (high a*, b* and C*: +4.56, +3.41 and +5.61, respectively). Increases in fatness score and carcass fat weight were associated with increases in a*, b* and C* (redness; +2.90 to +4.06 for a*; yellowness; +2.60 to +3.76 for b*; and vividness, +3.87 to +5.49 for C*) and a darker colored lean (L*; -1.56 to -3.23). As pH24h increased, a* (less red) and C* (less vivid) decreased (-3.06), whereas hue angle increased (+2.69) leading to poorer color. The selection of animals for high degree of muscularity or slaughter weight resulted in lighter and darker meat, respectively. The studied covariates could be used as indicators of Charolais beef color traits., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Data from birth to slaughter of cull cows allowed using a PCA-based approach coupled with the iterative K-means algorithm the identification of three rearing practices classes. The classes were different in their carcass characteristics. Old cows raised mainly on pasture have better carcass characteristics, while having an equivalent tenderness, juiciness, flavor, intramuscular fat content, and pHu to those fattened with hay or haylage. The Longissimus thoracis muscle of the cows raised on pasture (with high physical activity) showed greater proportions of IIA fibers at the expense of the fast IIX ones. Accordingly, the meat of these animals have better color characteristics. Superoxide dismutase (SOD1) and αB-crystallin quantified by Dot-Blot were the only other biomarkers to be more abundant in "Grass" class compared to "Hay" and "Haylage" classes. The relationships between the biomarkers and the 6 carcass and 11 meat quality traits were investigated using multiple regression analyses per rearing practices. The associations were rearing practice class and phenotype trait-dependent. ICDH and TP53 were common for the three classes, but the direction of their entrance was different. In addition, rearing practices and carcass traits were not related with Hsp70-Grp75 and μ-calpain abundances. The other relationships were specific for two or one rearing practices class. The rearing practices dependency of the relationships was also found with meat quality traits. Certain proteins were for the first time related with some beef quality traits. MyHC-IIx, PGM1, Hsp40, ICDH, and Hsp70-Grp75 were common for the three rearing practices classes and retained to explain at list one beef quality trait. A positive relationship was found between PGM1 and hue angle irrespective of rearing practices class. This study confirms once again that production-related traits in livestock are the result of sophisticated biological processes finely orchestrated during the life of the animal and soon after slaughter.

This study describes the development of the rabbit caecum microbiota and its metabolic activities from the neonatal (day 2) until the subadult period (day 70). The caecal microbiota was analysed using 16S rRNA gene approaches coupled with capillary electrophoresis single-stranded conformation polymorphism (CE-SSCP) and qPCR. At day 2, rabbits harboured population levels up to 8.4, 7.2 and 7.4 log(10) copy number g(-1) full caecum of the total bacteria, Bacteroides-Prevotella and Firmicutes groups, respectively. These populations reached their maximum levels from day 14 for Firmicutes groups (10.8 log(10) copy number g(-1) caecal content) and day 21 (11.4 and 10.7 log(10) copy number g(-1) caecal content of the total bacteria and the Bacteroides-Prevotella group, respectively). The archaeal population could be detected only from day 7 onwards (5.5 log(10) copy number g(-1) full caecum) and reached its maximum level at day 35 (7.4 log(10) copy number g(-1) caecal content). Similarity analysis, diversity calculation and quantitative evaluation of the stability of bacterial community CE-SSCP profiles provided some evidence that the caecal microbiota develops progressively from a simple and unstable community after birth into a complex and climax community in subadult rabbits. Meanwhile, the microbial activity evolved with the progressive decrease of the propionate/butyrate ratio towards a rabbit-specific value <1., (© 2011 INRA. FEMS Microbiology Ecology © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd.)

The archaeal community in the fermentative compartment and faeces of the cow and the rabbit were compared by analysis capillary electrophoresis single-stranded conformation polymorphism (CE-SSCP) profiles of 16S rRNA genes. Ruminal and faecal contents were sampled in five cows for three weeks. Hard and soft faeces were collected in 14 rabbits for three consecutive weeks and caecal contents were sampled in the third week. The archaeal community differed according to the host species (ANOSIM-R=0.53 and 0.72 respectively for the comparison of the fermentative compartments and faeces; P<0.001) and to the location within the digestive tract of both species (ANOSIM-R=0.37, 0.52 respectively for the cow and the rabbit; P<0.001). In both species, the archaeal community of the digestive tract was stable over weeks and varied very little between individual animals. The structure (NS) and the richness index (9.9+/-2.7, 10.1+/-3.1 respectively, NS) of the archaeal community were similar for the caecal content and the soft faeces which permitted to use the latter as a representative indicator., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

This work aimed to study the stability over time of the bacterial community in caecum and faeces of the rabbit (diversity index and structure) without experimental disturbance and to evaluate its relationships with environmental parameters. Soft and hard faeces of 14 rabbits were sampled for 5 weeks while caecal content was sampled on the 3rd week (by surgery) and the 5th week (at slaughter). Bacterial communities were assessed by studying CE-SSCP profiles of 16S rRNA genes fragments. Redox potential, pH, NH3-N concentration and volatile fatty acid concentrations were measured in the caecum. Data showed that bacterial communities of soft and hard faeces barely differed from that of the caecum (ANOSIM-R<0.25; p<0.05). Without disturbance, the bacterial communities of faeces were stable over time (ANOSIM-R<0.25; p<0.001). However, the bacterial communities of caecum and faeces were affected by the surgery (ANOSIM-R=0.22-0.33; p<0.001). The caecal content was an acidic (pH=6.03+/-0.33) and an anaerobic environment (redox potential=-160+/-43 mV). Only the redox potential was correlated with the diversity index of the bacterial community of the caecum (R(2)=0.35; p<0.05) and no environmental parameters were correlated to its structure., (Copyright 2009 Elsevier Ltd. All rights reserved.)

A bacteria library was constructed from the caecum of a rabbit maintained under standard conditions. The complete gene 16S rRNA gene was sequenced. The 228 clones obtained were distributed in 70 operational taxonomic units (OTUs). The large majority of the OTUs were composed of one or two clones and seven OTUs contained half of the sequences. Fourteen sequences had high similarity to the sequence already registered in databases (threshold of 97%). Only one of these sequences has been identified as Variovorax sp. (99% identity). Units were distributed mainly (94%) in the Firmicutes phylum. Three sequences were related to Bacteroidetes. Nine clusters were defined in the phylogenic tree. A great diversity of caecal bacteria of the rabbit was shown. Half of the sequences generated in this library were distributed in the phylogenetic tree near the sequences characterized previously in rabbit caecum (potential core species), and the other half of the sequences were well separated (satellite species).

We studied the efficiency of nitrogen utilisation by dairy cows, using three diets differing in the crude protein (CP) level but with similar deficits (10 g x kg(-1) dry matter, DM) in ruminal fermentable nitrogen. There was no difference in milk yield from the cows offered the three diets (130, 145 and 160 g CP x kg(-1) DM). The milk protein content differed between the two most extreme diets (28.9 vs. 29.9 g x kg(-1), P < 0.05), resulting in higher protein yields for the highest CP treatment (P < 0.01). The efficiency of nitrogen utilisation, calculated as the proportion of ingested nitrogen recovered in the milk, was significantly higher for the 130 g CP x kg(-1) DM diet than for the other two diets (0.37 vs. 0.33 and 0.32 respectively. P < 0.01). The different diets also resulted in different levels of nitrogen excretion into the environment (237, 270 and 330 g N x d(-1), P < 0.01). Hepatic deamination of the amino acids may have generated additional energy to enable the animal to make use of the additional nitrogen in the diet, resulting in an increase in plasma urea concentration.