C. Mugnai

Effect of genotype and rearing system on the native immunity and oxidative status of growing rabbits

Abstract To investigate the effects of genotype and rearing system on innate immunity and oxidative status, 40 weaned commercial hybrid (H) rabbits and 40 rabbits of a local population (LP) were assigned to two rearing systems: cage (17 rabbits/m2) and pen (1x2 m, 10 rabbits/m2). Rearing H rabbits in pen resulted in a higher lysozyme concentration (P<.05), an increased bactericidal activity (P<0.05) and a lower complement haemolytic activity (P<0.05) with respect to those reared in cage. Opposite results were obtained for LP rabbits. In addition, genotype H was more susceptibility to inflammation than LP in pen, whereas genotype LP suffered more in cage. A higher lipid (P<0.05) and protein (P<0.05) oxidation was found in Longissimus dorsi and Biceps femoris of rabbits H in pen compared to those in cage. An opposite trend was observed for LP rabbits. In cage, LP rabbits were more susceptible to oxidative stress than H rabbits. Taken together, our results show that immune and oxidative resistance ascribed to a specific genotype are important factors to be considered when a specific rearing system should be adopted. Considering this, rabbit LP seem to better adapt to larger spaces during growing.

Assessment of a reproduction rhythm based on the body condition of rabbit doe: preliminary results

Abstract The efficiency of rabbit farm mainly depends on the fertility and prolificacy of does, which in turn are modulated by genetic, feeding and management factors. The most important management factor for rabbit does is the reproductive rhythm. The aim of this work was to assess a reproductive rhythm in which the artificial insemination (AI) is done according to the body condition of doe. The study, involved 100 New Zealand White multiparous does submitted to AI for 5 consecutive cycles. Does were divided into 2 groups: CONTROL AI at 11d post partum and CONDITIONED AI when they reach a certain perirenal fat depot (between 15 and 30 g) estimated by ultrasound scanning. If does were too fat or lean, after an appropriate dietary protocol, they were weighed and submitted to ultrasound scanning again, and if they have a suitable body fat, artificially inseminated. At AI the does were weighed and submitted to ultrasound scanning of the perirenal region. Body Condition Score (loin, rump and hind leg), weight at kindling and at the weaning were also evaluated. On the day of insemination, does of both groups showed similar live weight and perirenal fat thickness (3862 vs 3813g and 0.64 vs 0.61 cm) respectively for CONDITIONED and CONTROL). These results were due to the fact that does are AI in different physiological stage; mainly lactating for the control group and dry for conditioned. Thus, during lactation does have a higher live weight for the presence of milk and for the higher incidence of the digestive tract, further the fat depot start to increase only after several days after weaning. Conditioned group showed higher fertility rate (83% vs 62%), number of live born pups (9.2 vs 7.4, P<0.05) and live weight of pups (512.8 vs 481.8 g, P<0.05), BCS of loin (1.1 vs 0.8, P<0.001), rump (1.0 vs 0.8, P<0.001) and hind leg (1.7 vs 1.4, P<0.001), perirenal fat weight (14.0 vs 10.9 , P<0.001), live weight at kindling (3865 vs 3553g, P<0.01), and doe at the weaning (3767 vs 3190g, P<0.01). In conclusion, conditioned rhythm, permitted to exhibit greater reproductive performance thanks to better energy balance. The higher cost of working hands would be counterbalanced by the higher fertility rate and prolificacy. Further investigation are needed to simplified and adapt conditioned rhythm to cycled production.

Effect of transport length and genotype on tonic immobility, blood parameters and carcass contamination of free-range reared chickens

Abstract The aim of the present study was to investigate the effect of transport on welfare traits, several haematological parameters and carcase hygiene in two different chicken genotypes (fast- and slow-growing strains) reared under free-range conditions. For this aim, two hundred male chicks, 100 from fast-growing (Ross 308, R) and 100 from slow-growing (Naked Neck, NN) strain were farmed. At the end of the rearing period, at 81 days of age, 56 birds/strain were randomly selected for slaughtering and submitted to two different pre-slaughter conditions: no transport (0h) or 4u2009hours of transport (4h). Tonic immobility (TI), blood parameters and carcase hygiene traits were determined. Strain and transport significantly affected TI of birds. Both experimental factors and their interaction significantly affected plasma creatine kinase, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase. Cholesterol and triglycerides were not different between the experimental groups, whereas glucose decreased after 4u2009hours of transport in both strains. A significant difference between groups for the heterophils/lymphocytes ratio after transport was also observed, with NN being higher than Ross. Concerning the oxidative stress, we observed a higher ROS production in NN chickens. The carcase microbial characteristics showed a higher level of contamination after the transport (total viable counts), but not concerning the Enterobacteriaceae counts.