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The present study evaluated the effects of feed supplemented with two dietary sources of n-3 polyunsaturated fatty acids (PUFAs; fish oil and extruded flaxseed) on the gut microbiota, caecal fermentations, gastrointestinal histology, and histochemistry in rabbits. Fifteen male New Zealand White rabbits were divided into three groups (n = 5/group) and fed with different diets from weaning (35 days of age) until slaughtering (90 days of age): C group, fed with a commercial diet; F group, supplemented with 10% of extruded flaxseed; and O group, supplemented with 3.5% of fish oil. At slaughter, the content of the stomach, duodenum, jejunum, ileum, caecum, and colon was collected and analyzed by Next Generation 16S rRNA gene sequencing. Tissue samples of the same tracts were evaluated with histological and histochemical analysis. Ammonia and lactic acid in the caecum were also quantified. Twenty-nine operational taxonomic units (OTUs) were significantly different between groups. Groups receiving n-3 PUFAs supplementation showed an increase in Bacteroidetes and Lachnospiraceae in several gastrointestinal tracts, while Bacilli abundance, as well as Firmicutes/Bacteroidetes ratio, were reduced compared to the control group (for all p < 0.05). Caecal ammonia was lower in the F than C group (p < 0.032), whereas no difference was found for lactic acid. Finally, histological evaluations revealed a mild hemorrhagic infiltration and vessels ectasia in the stomach mucosa of both F and O groups, but no effect of nutritional treatment was evidenced by the histochemical analyses. In conclusion, n-3 PUFAs supplementation could modify the rabbit gut microbiota and fermentation. The increase in beneficial bacterial populations may, at least partially, explain the positive effects of n-3 PUFAs diet supplementation on human and animals' health, although the appropriate dosage should be established. [ABSTRACT FROM AUTHOR]

Simple Summary: The microbial community that inhabits specific areas of the body, developing a symbiotic relationship with the host, is termed the microbiota. The intestinal microbiota plays a pivotal role in different physiological processes and is influenced by many factors, including nutrition. Goji berries are a popular nutraceutical product that have been proposed as a dietary supplement in some livestock species, including rabbits, but their effects on the composition of the microbiota have never been investigated. This study evaluated the effects of Goji berry supplementation on the microbiota of different digestive tracts (stomach, duodenum, jejunum, ileum, caecum and colon) of the rabbit, using a modern method of analysis. Our results suggest that Goji berries could modulate the microbiota of the rabbit's digestive tract increasing the growth of beneficial bacteria, such as Ruminococcaceae, Lachnospiraceae, Lactobacillaceae, and particularly, the genus Lactobacillus. These findings suggest that Goji berries could be used to produce innovative feeds for rabbits, although further studies are necessary to evaluate their impact on productive performance, gut immune system maturation, as well as resistance to gastrointestinal disorders. Goji berries show health benefits, although the possible mechanisms of action, including compositional changes in the gut microbiome, are still not fully understood. The aim of this study was to evaluate the effect of Goji berry supplementation on microbiota composition and metabolites in the digestive tracts of rabbits. Twenty-eight New Zealand White rabbits were fed with a commercial feed (control group, C; n = 14) or the same diet supplemented with 3% of Goji berries (Goji group, G; n = 14), from weaning (35 days old) until slaughter (90 days old). At slaughter, samples from the content of the gastrointestinal tracts were collected and analyzed by Next Generation 16S rRNA Gene Sequencing to evaluate the microbial composition. Ammonia and lactic acid were also quantified in caecum. Results showed differences in microbiota composition between the groups for two phyla (Cyanobacteria and Euryarchaeota), two classes (Methanobacteria and Bacilli), five orders, fourteen families, and forty-five genera. Ruminococcaceae (p < 0.05) and Lachnospiraceae (p < 0.01) were more abundant in G than in C group. Lactobacillaceae also showed differences between the two groups, with Lactobacillus as the predominant genus (p = 0.002). Finally, Goji berry supplementation stimulated lactic acid fermentation (p < 0.05). Thus, Goji berry supplementation could modulate gastrointestinal microbiota composition and caecal fermentation. [ABSTRACT FROM AUTHOR]

Simple Summary: Each animal hosts a large community of bacteria, protozoa, fungi, and algae that colonize every surface of the body. The microbiota is defined as the complex microbial community that inhabits a specific anatomic region of animals and interacts with it, developing symbiotic relationships. In this regard, the intestinal microbiota has a vital impact on metabolism, digestive activity, immune development, resistance to infections, health, and welfare of the host. Therefore, knowing its characteristics is important for understanding its action in these specific functions. This study provides a comprehensive map of the most common bacterial communities that colonize different parts of the rabbit gastrointestinal tract (stomach, duodenum, jejunum, ileus, caecum, and colon) while using a modern methodological approach and comparing it with the studies that have been conducted to date on other animal species and human beings. It could be the starting point for further research on gut microbiota modulation with the ultimate goal to promote the health and welfare, in order to prevent or treat gastrointestinal diseases, decrease antibiotic use, and increase the productive performance of rabbit. The microbiota is extremely important for the animal's health, but, to date, knowledge on the intestinal microbiota of the rabbit is very limited. This study aimed to describe bacterial populations that inhabit the different gastrointestinal compartments of the rabbit: stomach, duodenum, jejunum, ileum, caecum, and colon. Samples of the luminal content from all compartments of 14 healthy New White Zealand rabbits were collected at slaughter and analyzed using next generation 16S rRNA Gene Sequencing. The findings uncovered considerable differences in the taxonomic levels among the regions of the digestive tract. Firmicutes were the most abundant phylum in all of the sections (45.9%), followed by Bacteroidetes in the large intestine (38.9%) and Euryarchaeota in the foregut (25.9%). Four clusters of bacterial populations were observed along the digestive system: (i) stomach, (ii) duodenum and jejunum, (iii) ileum, and (iv) large intestine. Caecum and colon showed the highest richness and diversity in bacterial species, while the highest variability was found in the upper digestive tract. Knowledge of the physiological microbiota of healthy rabbits could be important for preserving the health and welfare of the host as well as for finding strategies to manipulate the gut microbiota in order to also promote productive performance. [ABSTRACT FROM AUTHOR]

Simple Summary: The weaning of young rabbits is a critical period that is often accompanied by digestive troubles. Innovations in feeding strategy are urgently needed to preserve rabbit health and to reduce the use of antibiotics. We show here that providing dehydrated alfalfa during weaning is a promising solution to manage health status by favoring the establishment of a proper digestive microbiota. The improvement of rabbit gut microbiota by modifying nutritional components of the feed or favoring its early intake of feed has been previously investigated. The early administration of dehydrated alfalfa (A) or fresh grass (G) for rabbits, during the peri-weaning period (30 and 45 days of age), and their effect on performance and caecal microbiota compared to a standard diet (C) were evaluated. Until 15 days of age, nine litters/group were housed in the maternal cage and milked once per day. From 15 to 30 days, the young rabbits could consume both milk and solid feed (pelleted for C or supplemental feed for A and G). At 30 days of age, the rabbits were weaned and, until 45 days, were kept in single cages following the same dietary protocol. No significant changes were found in the milk intake or the individual weight of young rabbits at 30 and 45 days. The caecal Firmicutes/Bacteroidetes (bacterial phyla ratio) increased with age (from 2.43 to 6.05 on average, at 30 and 45 days). The Ruminococcaceae/Lachinospiraceae (bacterial family ratio) was highest in the A group at both ages, followed by G then C. The early administration of dehydrated alfalfa is a promising solution to improve health status by favoring an appropriate digestive microbiota. [ABSTRACT FROM AUTHOR]