Parity-Associated Differences in the Antioxidants and Fecal Microbiota of Bactrian Camels

Camels survive in deserts through unique, adapted metabolic and immunological processes that are normally lethal to other species. Antioxidants and the gastrointestinal microbiota play major roles in redox homeostasis, yet they remain unexplored in camels to date. The objectives of this study were to characterize the dynamics of milk antioxidants, serum antioxidants, and the fecal microbiome of lactating Bactrian camels with different parities. In total, 30 lactating camels were selected and categorized into the following 3 groups: 10 were assigned to the first parity group (P_1), 10 were classified into the third parity group (P_3), and 10 belonged to the fifth parity group (P_5). The antioxidant parameters of the lactating camels were determined in milk and serum. The fecal microbial community of lactating camels was assessed using 16S rRNA amplicon sequencing, and the resulting library was sequenced on an Illumina NovaSeq platform. The amount of total antioxidant capacity (T-AOC) and antioxidant activity for polypepetides (DPPH) in the third parity was the highest among the groups both in the camel milk and its serum. In the case of hydroxyl radical (OH) and SOD, the amounts were 9.62 U/mL (SEM = 0.4950) and 13.64 U/mL (SEM = 0.5144), respectively, for P_1 in the serum, which were extremely significantly greater than those of the other groups. The Shannon index was significantly different between the P_1 group and either the P_3 or P_5 group. Additionally, Simpson's diversity index significantly differed between the P_1 group and the P_5 group. Furthermore, the number of OH in camels is positively associated with the metabolic pathway of non-oxidative pentose phosphate pathway and ANAGLYCOLYSIS-PWY. In conclusion, this study revealed that different parities were associated with distinct levels of antioxidant parameters and fecal microbial ecologies in lactating Bactrian camels, where parity affects metabolic and microbial health. Understanding these dynamics in camels could optimize their nutritional management, enhancing their welfare in challenging environments.