Probiotics in Rabbit Farming: Growth Performance, Health Status, and Meat Quality.

The rabbit's complex microbiota of the gastrointestinal tract (GIT) plays a critical role in feed digestion, in vitamin production, in fermentative activity with production of volatile fatty acids, and stimulation of immune response, as well as in the infection defence against pathogens and countering environmental stresses. To prevent digestive disorders of this fragile ecosystem, rabbit breeders adopt suitable diets supplemented with additives such as probiotics. Probiotics can interact with the host and with the other microflora leading to an increased health status. A review on the effects of probiotics on rabbit growth performance, health status, and meat quality was conducted to reduce the incidence of digestive diseases and enhance productive performance. Some authors observed that the supplementation of probiotics to the diet improved feed conversion ratio and growth and digestion coefficients, while other authors reported a lack of effect on the live performance. Benefits derived from the use of probiotics were observed on the mortality and the morbidity. The studies performed, to evaluate the effects of probiotic supplementation in diets on the immune response, showed variations in the results. Some authors reported no significant effect on haematological parameters, such as total protein, immunoglobulins, and IgG, while others observed a significant increase or decrease of the same parameters. Most of the research reported significant modifications of intestinal morphology and positive effects on the GIT microbiota, supporting the host's natural defences. Regarding the carcass and meat quality, the studies reported only partial and opposing results.

Effects of garlic powder and salt additions on fatty acids profile, oxidative status, antioxidant potential and sensory properties of raw and cooked rabbit meat burgers.

Rabbit burgers were evaluated for fatty acids profile, oxidative status, antioxidant potential and sensory during storage time of seven days at 4 °C. The aim of the research study was to evaluate if a common culinary spice as garlic could overcome the controversy effects of salt (mostly related to a pro-oxidant effect). Therefore, four formulations were made: only meat (control, C) meat added with garlic powder at 0.25% (G), meat added with salt at 1.00% (S) and meat added with garlic powder (0.25%) and salt (1.00%) (GS). As results, it was highlighted that garlic powder was not capable to reduce significantly the negative effect related to the salt addition. Salt induced different modifications to burgers leading to a more liked product due to its properties to enhance sensory characteristics, on the other hand, induced different oxidation processes that could decrease the nutritional value. Further studies are needed to better elucidate if different garlic products/concentrations could apport higher beneficial effects.

The influence of dietary chestnut and quebracho tannins mix on rabbit meat quality.

Tannins were recently evaluated as feed additives in order to increase antioxidant compounds in animal diet, mainly to enhance resistance to lipid oxidation in meat. Rabbit meat is one of the most susceptible animal products, thus the main aim of this study was to evaluate the capacity of tannins to elongate shelf life of rabbit meat. Ninety hybrid rabbits were fed with three different diets: basal diet (control, C) and basal diet supplemented with 0.3% or 0.6% of tannins mix. Meat samples were refrigerated as raw at 4°C up to 11 days and analysed both as raw and cooked for physical-chemical characteristics, fatty acids profile, lipid oxidation and antioxidant capacity. Results showed that dietary tannins affected meat colour of raw samples (mostly yellowness). Lipid peroxidation (TBARS) of raw samples was lower in tannins group than C group; a further inhibition of peroxidation was showed also in cooked samples only by the highest dose of tannins mix. Moreover, antioxidant capacity (ABTS) of raw samples increased with the percentage of tannins. In conclusion, supplementation with 0.6% of tannins mix seems to positively affect the lipid peroxidation and antioxidant capacity of meat without modifying the intrinsic characteristics of rabbit meat.

Dietary supplementation of chestnut and quebracho tannins mix: Effect on caecal microbial communities and live performance of growing rabbits.

The interest in antimicrobial compounds as feed additives is currently increasing. Among different options, tannins seem to have several beneficial effects when employed in animals diet. The present study aimed at investigating the influence on caecal microbial communities of the supplementation of a chestnut and quebracho tannins mix in meat rabbit's diet, also considering animals live performances. Four groups of rabbits were fed with a different diet: a control diet (C); a control diet with coccidiostat (CC), and two experimental diets with 0.3% (T0.3) and 0.6% (T0.6) chestnut and quebracho tannins mix. For microbial analysis, culture-dependent and culture-independent methods were employed. Live performances were not significantly affected by tannins mix supplementations, as well as culturable microbial loads of E. coli, Enterobacteriaceae, Bacteroides spp. and Bifidobacterium spp. C. perfringens was always under the detection limit. A consistent result was obtained by qPCR. As for PCR-DGGE analysis, the Richness and evenness (Shannon-Weiner index) of bacterial communities in caecum resulted significantly higher in control samples (C and CC) than in those from rabbit fed with tannin-containing diets. Sequencing analysis revealed that the phylum Firmicutes was less represented in samples from control groups. As for the methanogen archaeal DGGE, no significant differences were found in richness and diversity among different groups, all dominated by Methanobrevibacter spp.. This work highlights the potential antimicrobial effect of chestnut and quebracho tannins mix in an in vivo system revealed by molecular analysis.

Effect of turmeric powder (Curcuma longa L.) and ascorbic acid on physical characteristics and oxidative status of fresh and stored rabbit burgers.

The objective of this study was to evaluate the effect of Curcuma longa powder and ascorbic acid on some quality traits of rabbit burgers. The burgers (burgers control with no additives; burgers with 3.5 g of turmeric powder/100g meat; burgers with 0.1g of ascorbic acid/100g meat) were analyzed at Days 0 and 7 for pH, color, drip loss, cooking loss, fatty acid profile, TBARS, antioxidant capacity (ABTS, DPPH and FRAP) and microbial growth. The addition of turmeric powder modified the meat color, produced an antioxidant capacity similar to ascorbic acid and determined a lower cooking loss than other formulations. Turmeric powder might be considered as a useful natural antioxidant, increasing the quality and extending the shelf life of rabbit burgers.