Sika deer (Cervus nippon) have different dietary preferences to other ruminants and are tolerant to tannin-rich plants. Because the rumen bacteria in domestic Sika deer have not been comprehensively studied, it is important to investigate its rumen bacterial population in order to understand its gut health and to improve the productivity of domestic Sika deer. The rumen bacterial diversity in domestic Sika deer (Cervus nippon) fed oak leaves- (OL group) and corn stalks-based diets (CS group) were elucidated using 16S rRNA gene libraries and denaturing gradient gel electrophoresis (DGGE). Overall, 239 sequences were examined from the two groups, 139 clones from the OL group were assigned to 57 operational taxonomic units (OTUs) and 100 sequences from the CS group were divided into 50 OTUs. Prevotella-like sequences belonging to the phylum Bacteroidetes were the dominant bacteria in both groups (97.2% OL and 77% CS), and sequences related to Prevotella brevis were present in both groups. However, Prevotella shahii-like, Prevotella veroralis-like, Prevotella albensis-like, and Prevotella salivae-like sequences were abundant in the OL group compared to those in the CS group, while Succinivibrio dextrinosolvens-like and Prevotella ruminicola-like sequences were prevalent in the CS group. PCR-DGGE showed that bacterial communities clustered with respect to diets and the genus Prevotella was the dominant bacteria in the rumen of domestic Sika deer. However, the distribution of genus Prevotella from two groups was apparent. In addition, other fibrolytic bacteria, such as Clostridium populeti and Eubacterium cellulosolvens were found in the rumen of domestic Sika deer. The rumen of domestic Sika deer harbored unique bacteria which may represent novel species. The bacterial composition appeared to be affected by diet, and sequences related to Prevotella spp. may represent new species that may be related to the degradation of fiber biomass or tannins. Moreover, the mechanism and biological functions of Prevotella spp. in the rumen ecosystem, and synergistic interactions with other microorganisms should be noticed.

This study was conducted to investigate whether different dietary Cyberlindnera jadinii levels affect growth performance, serum immunity, antioxidant capacity, and intestinal microbiota in growing raccoon dogs. Forty-five healthy male raccoon dogs were randomly assigned to three treatment groups, with 15 raccoon dogs per group. Each raccoon dog was housed in an individual cage. The raccoon dogs in the three groups were fed diets supplemented with Cyberlindnera jadinii at dosages of 0 (N group), 1 × 10⁹ (L group) and 5 × 10⁹ CFU/g (H group). A 7-day pretest period preceded a formal test period of 30 days. The results showed that Cyberlindnera jadinii in the L and H groups improved average daily gain (ADG) (P < 0.05) and decreased the ratio of feed to weight (F/G) (P < 0.05). Serum immunoglobulins A and G levels were increased in the L and H groups compared to the N group (P < 0.05). Cyberlindnera jadinii in the L and H groups increased serum superoxide dismutase activity (P < 0.05), and serum glutathione peroxidase activity was increased in the L group compared to the N group (P < 0.05). The relative abundance of Firmicutes and Actinobacteriota were increased, and the relative abundance of Bacteroidota was decreased in the L and H groups compared to the N group (P < 0.05). The relative abundance of Proteobacteria and Cyanobacteria was increased in the H group compared to the other two groups (P < 0.05). The ratio of Firmicutes to Bacteroidetes in the Cyberlindnera jadinii supplementation groups increased compared with the N group (P < 0.05). The relative abundance of Megasphaera and Bifidobacterium were increased, and the relative abundance of Prevotella was decreased in the L and H groups compared to the N group (P < 0.05). The relative abundance of Dialister was increased, while the relative abundance of Blautia was decreased in the H group compared to the other two groups (P < 0.05). The relative abundance of Agathobacter was decreased in the H group compared to the N group (P < 0.05). In conclusion, dietary supplementation with Cyberlindnera jadinii increased growth performance, serum immunity, antioxidant capacity, and improved intestinal microbiota in growing raccoon dogs. Cyberlindnera jadinii can therefore be used as a growth promoter in raccoon dogs.

The objective of this study is to study the effects of dietary intake levels on energy metabolism, carbon (C), and nitrogen (N) balance and to determine the maintenance requirements of energy and protein for male sika deer during their growing period. A total of 16 1-year-old male sika deer with similar body weight (BW) (63.25 ± 2.42 kg) were selected, with four animals per feed intake level. The feeding levels of the four groups for deer were 40, 60, 80, and 100% of the recommended amount, respectively. The nutrient digestibility and methane production were measured through digestion trials and respiratory trials. A 4 × 4 Latin Square design was performed in a respirometry trial. The results show that the apparent digestibility of C and N gradually increased as the level of feed intake decreased. Furthermore, with a decrease in feed intake level, the metabolic energy intake (MEI), heat production (HP), and retained energy (RE) of male sika deer significantly decreased (P < 0.01). The requirements of metabolic energy for maintenance (MEm) and net energy for maintenance (NEm) of growing deer are 251.17 and 223.62 kJ kg⁻¹BW^0.75d⁻¹, respectively, as estimated according to the logarithmic regression equations between HP and MEI. The net N requirement for maintenance (NNm) and net protein requirement for maintenance (NPm) of growing male sika deer based on the linear relationship between retained nitrogen (RN) and daily nitrogen intake (NI) were 251.8 mg kg⁻¹BW^0.75d⁻¹ and 1.57 g kg⁻¹BW^0.75d⁻¹, respectively. The NEm and NPm values obtained from this experiment fill the gap in net energy and protein requirements and serve as basic data for establishing the nutritional standards forsika deer breeding in China.

Introduction: This study aimed to investigate the effects of Cyberlindnera jadinii supplementation on the growth performance, nutrient utilization, serum biochemistry, immunity, antioxidant status, and intestinal microbiota of raccoon dogs during the winter fur-growing period.Methods: Forty-five 135 (±5) day-old male raccoon dogs were randomly assigned to three dietary groups supplemented with 0 (group N), 1 × 10⁹ (group L) and 5 × 10⁹ CFU/g (group H) Cyberlindnera jadinii, with 15 raccoon dogs per group.Results: The results showed that Cyberlindnera jadinii in groups L and H improved average daily gain (ADG) and decreased feed-to-weight ratio (F/G) (P < 0.05). No significant difference was found in nutrient digestibility and nitrogen metabolism among the three groups (P > 0.05). Compared with group N, serum glucose levels were lower in groups L and H (P < 0.05). The levels of serum immunoglobulins A and G in group L were higher than those in the other two groups (P < 0.05), and the levels of serum immunoglobulins A and M in group H were higher than those in group N (P < 0.05). Supplementation with Cyberlindnera jadinii in groups L and H increased serum superoxide dismutase activity, and the total antioxidant capacity in group H increased compared with group N (P < 0.05). The phyla Bacteroidetes and Firmicutes were dominant in raccoon dogs. The results of principal coordinate analysis (PCoA) showed that the composition of microbiota in the three groups changed significantly (P < 0.05). The relative abundance of Campylobacterota was increased in the H group compared to the N and L groups (P < 0.05). The relative abundance of Sarcina was increased in group L compared with the other two groups (P < 0.05), while the relative abundance of Subdoligranulum and Blautia were decreased in group H compared with the other two groups (P < 0.05). Also, the relative abundance of Prevotella, Sutterella and Catenibacterium was higher in group L (P < 0.05) compared with group H.Discussion: In conclusion, dietary supplementation with Cyberlindnera jadinii improved growth performance, antioxidant activity, immune status, and improved intestinal microbiota in winter fur-growing raccoon dogs. Among the concentrations tested, 1 × 10⁹ CFU/g was the most effective level of supplementation.