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.

Methionine is the first or second limiting amino acid for ruminants, such as sika deer, and has a variety of biological functions such as antioxidant activity, immune response, and protein synthesis. This study aimed to investigate the effects of methionine supplementation on antler growth, serum biochemistry, rumen fermentation, and the bacterial community of sika deer during the antler-growing period. Twelve 4-year-old male sika deer were randomly assigned to three dietary groups supplemented with 0 g/day (n = 4, CON), 4.0 g/day (n = 4, LMet), and 6.0 g/day (n = 4, HMet) methionine. No significant difference (p > 0.05) was found in the production performance between the three groups, but antler weight was higher in both the LMet and HMet groups than in the CON group. Methionine supplementation significantly increased the serum glutathione peroxidase activity (p < 0.05). The serum immunoglobulin G level was significantly higher in the HMet group than in the other two groups (p < 0.05). No significant effect was found on the apparent amino acid digestibility of the three groups, but cysteine and methionine digestibility were higher in the LMet group. The serum hydroxylysine level was significantly lower in the LMet and HMet groups, whereas the serum lysine level was significantly lower in the HMet group compared with the CON group (p < 0.05). The LMet group had the highest but a nonsignificant total volatile fatty acid content and significantly higher microbial protein content in the rumen than the CON group (p < 0.05). The phyla Bacteroidetes, Firmicutes, and Proteobacteria were dominant in the rumen of the sika deer. The principal coordinate analysis (PCoA) and analysis of similarities (ANOSIM) results showed a significant change in the bacterial composition of the three groups (p < 0.05). The relative abundance of Prevotella and Rikenellaceae-RC9 was significantly higher in the LMet group compared with the CON group and CON and HMet groups, respectively. These results revealed that methionine supplementation improved the antioxidant activity and immune status, affecting amino acid metabolism and rumen microbial composition of the sika deer.

This experiment was set to investigate the effects of DL-methionine (DL-met) supplement on growth performance and amino acid digestion and plasma concentrations in sika deer calves. Twelve healthy 5-month-old sika deer (29.44 ± 2.86 kg initial bodyweight) were randomly divided into three groups (4/group) and one sika deer per replicate. Levels of Met supplement in three treatments were 0, 1 g/kg and 2 g/kg, respectively. The results showed that the average daily gain for the early 35-day study period tended (P = 0.07) to increase linearly as the Met supplement increased, the feed to gain ratio (F : G) for the early period decreased (linearly and quadratically, P < 0.05), and, in the late 35-day study period, tended (linearly, P = 0.08) to decrease as dietary Met increased. The apparent digestibility of Met increased (linearly and quadratically, P < 0.01) with graded amounts of supplemental Met, and the apparent digestibilities of valine, leucine, isoleucine, phenylalanine, glycine, aspartic and cystine showed a linear increase (P < 0.05). Plasma glycine, proline and isoleucine concentrations increased linearly and quadratically (P < 0.01) with Met supplementation, plasma serine and leucine increased linearly (P < 0.05), and plasma histidine, lysine, arginine and NH3 increased quadratically (P < 0.01 or P < 0.05), with graded amounts of supplemental Met. Met supplementation in the diet improved feed utilisation and amino acid (AA) nutrient digestion, and affected plasma AA concentrations in sika deer calves.

Amino acid balance is central to improving the efficiency of feed protein utilization and for reducing environmental pollution caused by intensive farming. In previous studies, supplementation with limiting amino acids has been shown to be an effective means of improving animal nutrient utilization and performance. In this experiment, the effects of methionine on the apparent digestibility of nutrients, antler nutrient composition, rumen fluid amino acid composition, fecal volatile fatty acids and intestinal bacteria in antler-growing sika deer were investigated by randomly adding different levels of methionine to the diets of three groups of four deer at 0 g/day (CON), 4 g/day (LMet) and 6 g/day (HMet). Methionine supplementation significantly increased the apparent digestibility of organic matter, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in the LMet group (p < 0.05). The crude protein and collagen protein of antlers were significantly higher in the LMet and HMet groups compared to the CON group and also significantly higher in the HMet group compared to the LMet group, while the calcium content of antlers was significantly lower in the HMet group (p < 0.05). Ruminal fluid free amino acid composition was altered in the three groups of sika deer, with significant changes in aspartic acid, citrulline, valine, cysteine, methionine, histidine and proline. At the phylum level, Firmicutes and Bacteroidetes were highest in the rectal microflora. Unidentified bacterial abundance was significantly decreased in the HMet group compared to the CON group. Based on the results of principal coordinate analysis (PCoA) and Adonis analysis, there was a significant difference in the composition of the intestinal flora between the CON and HMet groups (p < 0.05). At the genus level, compared with the CON group, the abundance of Rikenellaceae_RC9_gut_group and Lachnospiraceae_UCG-010 in the LMet group increased significantly (p < 0.05), the abundance of dgA-11_gut_group in the HMet group decreased significantly (p < 0.05) and the abundance of Lachnospiraceae_UCG-010, Saccharofermentans and Lachnospiraceae_NK3A20_group increased significantly. Taken together, the results showed that methionine supplementation was beneficial in increasing the feed utilization efficiency and improving antler quality in sika deer, while affecting the composition of fecal bacteria.

American ginseng residue is an industrial by-product of ginseng saponin extraction, including polysaccharides and amino acids; however, it is often discarded into the natural environment, representing a waste of resources as well as an environmental issue. In this study, we examined the effects of adding American ginseng residue to the basal diet of sika deer. Twelve antler-bearing male sika deer were assigned randomly to groups fed a diet supplemented with 0% (CON), 1% (LGR), and 3% (HGR) American ginseng residue, respectively, (n = 4 per group) for 5 weeks. Supplementation with 3% American ginseng residue significantly increased antler production and feed utilization efficiency in antler-bearing sika deer (p < 0.05). There were no significant differences in serum biochemical indexes among the three groups, but serum immunoglobulin A and glutathione peroxidase levels were significantly increased in the LGR and HGR groups (p < 0.05). Supplementation with American ginseng residue affected rumen fermentation in sika deer, significantly increasing the rumen contents of acetic acid, propionic acid, and total volatile fatty acids, and decreasing rumen fluid pH (p < 0.05), but had no significant effect on microbial protein or ammoniacal nitrogen content. American ginseng residue also affected the rumen bacterial composition, with significant up-regulation of Bacteroidota abundance in the HGR group, significant increases in Fibrobacterota and Fibrobacter abundance in the LGR group, and a significant decrease in Oscillospiraceae_UCG-005. Supplementation with ginseng residue had no significant effect on volatile fatty acids in the feces of sika deer, but did affect the composition of fecal bacteria, with significant decreases in Desulfobacterota and Rikenellaceae_RC9_gut_group in the HGR group, and a significant increase in Ruminococcus in the LGR group (p < 0.05). In addition, the abundance of Paeniclostridium in the feces decreased linearly with increasing concentration of ginseng residue, with a significant difference among the groups (p < 0.05). This study comprehensively evaluated the effects of American ginseng residue as a potential feed additive on the production performance and gastrointestinal bacterial community in antler-bearing sika deer. The results indicated that ginseng residue was a suitable feed additive for improving production performance and health in sika deer.

New Delhi-Metallo-1–producing (NDM-1–producing) Enterobacter cloacae is one of the highly resistant pathogens affecting the intensive care unit. A previous study reported that ST418 was the main epidemic type of NDM-1–producing E. cloacae in Shenzhen, China. However, few NDM-1–producing carbapenem-resistant Enterobacter cloacae ST418 strains have been described. In this study, we collected and characterized an NDM-1–producing carbapenem-resistant E. cloacae strain, E70, from a patient in Guangzhou. E70 was resistant to multiple antibiotics, including imipenem and meropenem. S1-Pulsed field gel electrophoresis and southern blotting showed that E70 harbored four plasmids and that the bla _NDM-1 gene was located on an ∼50 kb plasmid. Conjugation experiments revealed that the two smaller plasmids were transferable and that transconjugants obtaining one or both plasmids acquired different antimicrobial resistances. Whole-genome sequencing and analysis revealed that E70 belonged to ST418. The bla _NDM-1 and bla _SHV-12 genes coexisted on the 53.7 kb IncX3 plasmid pE70-NDM1, whereas the bla _CTX-M-3 and bla _TEM-1 genes were located on another untyped 26.0 kb plasmid, pE70-TEM1. The bla _NDM-1 plasmids in Enterobacter cloacae ST418 may serve as an important vehicle in the dissemination of NDM, and the coexistence of transferable plasmids increases the possibility of rapid horizontal spread of multidrug resistance genes. Long-term monitoring and detailed study are necessary for the prevention of bla _NDM-1 -carrying E. cloacae infection.