Agricultural by-products could be used as alternative raw materials in rabbit nutrition as they have been found to be highly nutritious and low cost feeding sources. The aim of this study was to estimate the nutritive value and potential use of bilberry pomace (BP) for growing rabbits. A total of 144 Grimaud rabbits (35 days old) were allotted to four groups and fed with a diet containing increasing level of BP: BP0 (basal diet), BP5, BP10 and BP15 containing 0, 50, 100 and 150 g/kg respectively. Growth trial lasted 48 days; apparent digestibility was evaluated, starting at 46 days of age, over 4 consecutive days. The nutritive value of BP was measured using the mean digestibility of the experimental diets. At 83 days of age, rabbits were slaughtered: blood, and liver and kidney samples were collected in order to determine the blood parameters and the antioxidant enzyme activities of the tissues. Moreover, caecal content was sampled and gut microbiota assessed by means of amplicon-based high-throughput 16S rRNA sequencing and PCR-denaturing gradient gel electrophoresis. The digestible protein was estimated to 104 g/kg of DM while digestible energy to 9.44 MJ/kg DM for incorporation rate up to 150 g/kg. During the finishing period, average daily feed intake and feed conversion ratio showed linear response to BP increase (P=0.008 and <0.001, respectively). During all the period, both parameters decreased linearly and quadratically with increasing BP inclusion levels (P<0.001) up to 100 g/kg of BP. A significant effect of the antioxidant status was found in the kidneys and liver (P<0.05) where the glutathione peroxidase activity increased as the BP increased. As far as gut microbiota is concerned, BP increased the relative abundance of the Clostridium, Oscillospira, Ruminococcus and Ruminococcaceae species which were clearly associated with the BP inclusion level. In conclusion, BP showed a potential use as an alternative protein and fibre sources for growing rabbits.

Relict endangered populations may be especially vulnerable to the effects of climate change. A data series for the period 1974–2003 was used to examine shifts in brown bear Ursus arctos food habits in its south-westernmost European population. This focused on the hyperphagic season, when bears gain the fat that is essential for winter dormancy and reproduction. General climatic indicators were predictors of diet trends. Other variables potentially able to modify brown bear food habits at the local scale were accounted for by considering two areas where local conditions changed in different ways during the study period. General climatic indicators such as temperature and the winter North Atlantic Oscillation index were good predictors of some diet trends, although local factors seemed to modulate the potential response of food habits to recent climate change. Boreal and temperate food items decreasingly contributed to brown bear diet, replaced by increasing contributions of southern foods, which suggested that warmer temperatures might determine the occurrence of some food items in the diet of Cantabrian brown bears through effects on plant distribution and phenology. At the local scale, high cattle density in one of the study areas limited food sources available for brown bears. Important food sources for brown bears, such as heath-like Vaccinium formations and old-growth oak forest in the Cantabrian Mountains, require increased levels of protection.