Aim: The objective of this work was to study the growth performance, slaughter traits, meat quality, and metabolic profile in rabbits of local Algerian population and a synthetic line. Materials and Methods: In total, 120 weaned rabbits were used (60 per group). Growth traits were recorded from weaning (35 days) to slaughter (91 days). At slaughter, carcass traits, meat quality, and metabolic profiles were measured. Results: The synthetic line showed heavier total weight and faster daily weight gain than the local population (+15% and +19%, respectively), better feed conversion (3.92 vs. 4.81 g/g), and heavier weight of cold carcass, and perirenal fat (+15%). No differences were found between the two groups in dressing out percentage, muscular pH, weight of liver, or scapular fat. Wider intestinal villi were found in the synthetic line (+20%, p<0.0001) allowing better absorption surface in this line. The synthetic line also showed higher fat content (3.41% vs. 2.22%, p<0.0001) in the meat and lower protein content (22.02% vs. 18.98%, p=0.0002). Glucose level was 19% higher in the local population than in the synthetic line. Conclusion: The synthetic line is well adapted to the local conditions of Algeria. This line has shown better growth, daily gain, and feed conversion, due to its better intestinal absorption surface.

The aim of this study was to analyse the relationships between kit birth weight and litter size with kit survival from birth to weaning, and to estimate the effects of place of birth, nest quality, cannibalism, lactation, parity order, season and sex. A total of 1696 kits from 82 females of the ITLEV2006 synthetic line were used in this study. A logistic regression was performed. Kit birth weight was directly related to the probability of the kit’s survival from birth to weaning, and increasing birth weight by one gram increased the likelihood of kit survival by 8% to 10% (P<0.001). In line with the decrease in birth weight of kits as the number of kits at birth increases, litter size showed a negative relationship to the probability of survival from birth to weaning, and increasing the litter by one kit at birth decreased the probability of survival of the kits by 5% to 9% (P<0.05). Regarding effects, cannibalism events in the litter decreased the probability of survival of the kits in the first week of life (P<0.01). Being born in the cage decreased the probability of survival of the kits from birth to weaning, and kits born outside the nest had a lower chance of survival than those born inside the nest (P<0.01). The order of parturition had a positive effect on probability of survival of the kits from 5 days of age to weaning (P<0.05). Female kits had a lower chance of survival than male kits, but only until 5 days of age (P<0.01). The lactation status displayed a negative effect on the probability of survival of the kits in the first week of life, and kits gestated in lactating females had a lower chance of survival than those gestated in non-lactating females (P<0.05). In conclusion, the probability of kit survival in the first days after parturition was affected mainly by its weight at birth, litter size, cannibalism events, place of birth of kit, parity order, sex and lactation status, while the probability of kit survival at weaning was directly related to its weight at birth, litter size, place of birth of kit and parity order.

A divergent selection experiment for litter size variability has been carried out successfully in rabbits. The aim of this work was to determine the evolution of body weight and perirenal fat thickness throughout the productive lifespan of females in the high litter size variability (H) line and the low litter size variability (L) line. The traits measured in females from both the H and L lines were body weight and perirenal fat thickness at the first mating and delivery, the second mating and delivery, and the last mating. Statistical analyses were performed using Bayesian methods. The H and L lines showed similar body weights in the first and second reproductive cycles. However, the L line exhibited higher perirenal fat thickness than the H line at the second delivery (9.19 mm vs. 9.00 mm, respectively P = 87%), despite having almost one young rabbit more at birth. At the end of reproductive life, the H line had a 4.4% higher body weight and a 3.4% higher perirenal fat thickness than the L line. In conclusion, decreasing litter size variability improves the mobilisation and management of body fat reserves in females from the second reproductive cycle.

The objective of this work is the didactic integration of apps that are used in the management of livestock farms in the Degree in Agro-Food and Agro-Environmental Engineering. The academic results indicated that the scores improved by 1.67 points when the apps were included in the teaching. In addition, a questionnaire was carried out for the student, resulting that more than 66% of the students answered "Totally agree" to the sentence "The proposed task has made it easier for me to learn the subject". This was also the response for 33% of the students to the sentences "The use of apps has helped me understand the subject" and "I would recommend the use of apps in other subjects of the subject". The answer "Neither agree nor disagree" was the answer selected by 66% of the students for the sentence "The use of apps has brought me closer to that of the livestock sector". The conclusions of this work are that the introduction of apps in teaching improves the academic performance of the student as they facilitate learning. It would be advisable to use this methodology to other subject.

Background The gut-derived metabolites are key actors in the host-microbiota crosstalk and can have either beneficial or detrimental effects on the host. Gut metabolome could be a potential strategy to enrich the knowledge of host-gut interactions, providing another way of improving key traits such as animal resilience and welfare in livestock systems. Animal resilience has now become a critical livestock trait because of the high demand for more sustainable productions. Environmental variance (VE), the within-individual variance of traits due to environmental factors, is used as a key measure to improve resilience. Studying the gut microbiome composition can reveal the mechanisms behind animal resilience due to its influence on host immunity. The aim of this study was to identify the gut-derived metabolites underlying the VE of litter size (LS), for which we performed an untargeted gut metabolome analysis in two rabbit populations divergently selected for low (n = 14) and high (n = 14) VE of LS. Partial least square-discriminant analysis and Bayesian statistics were computed to determine dissimilarities in the gut metabolites of the rabbit populations. Results We identified 15 metabolites that can discriminate between rabbit populations with a prediction performance of 99.18% for resilient and 90.42% for non-resilient populations. The most reliable metabolites identified were glycerophosphoglycerol, equol, behenoylcarnitine, arachidoylcarnitine, ethyl beta-glucopyranoside, 3-(4-hydroxyphenyl)lactate, N6-acetyllysine, 5-aminovalerate and succinylcarnitine. A great abundance of acylcarnitines and metabolites from the phenylalanine, tyrosine, and tryptophan metabolism were found in the non-resilient population. Acylcarnitines and metabolites from AAAs (like kynurenine and anthranilate) can impact the inflammatory response and the health status of animals. Conclusions This is the first study to identify gut metabolites that can act as the VE of LS biomarkers as well as resilience biomarkers. The smaller number of acylcarnitines and metabolites derived from the phenylalanine, tyrosine and tryptophan metabolism suggested that resilient animals were better able to cope with stressful events. However, further studies will be needed to determine the causal role of these metabolites in health and disease.