Nutrient Utilization and Gut Microbiota Composition in Giant Pandas of Different Age Groups.

Simple Summary: The dietary structure and gut microbiota of giant pandas play an important role in nutrient utilization. The relationship between age-related dietary changes, nutrient digestibility, and gut microbiota composition is not fully understood. According to this study, bamboo consumption dramatically decreases with age. Meanwhile, a notably higher amount of bamboo shoots are consumed by geriatric giant pandas (GGP), which may be an important source of nutrients for them as bamboo shoots have a strong positive correlation with the concentration of crude protein (CP) and specific amino acids. In addition, the digestibility of crude fiber (CF) and certain amino acids are significantly correlated with the abundance of specific bacterial genera, highlighting that an age-related shift in gut microbiota has an influence on nutrient utilization. Our study provides new insights into the further study on the mechanisms underlying the effects of certain gut microbiota on nutrient digestion. Proper feeding and nutrition are vital for maintaining the health of giant pandas (GPs), yet the impact of dietary changes and gut microbiota on their nutrient utilization remains unclear. To address these uncertainties, we investigated nutrient intake and apparent digestibility, as well as gut microbiota composition across different age groups of giant pandas: sub-adults (SGPs), adults (AGPs), and geriatrics (GGPs). Our findings revealed notable shifts in dietary patterns from SGPs to GGPs. As they aged, significantly more bamboo shoots and less bamboo were consumed. Consequently, GGPs showed significantly reduced crude fiber (CF) intake and digestibility, while crude protein (CP) did not alter significantly. In addition, 16S rRNA microbial sequencing results showed that unidentified_Enterobacteriaceae and Streptococcus were the dominant genera among all age groups. The relative abundance of the genus Enterococcus in GGPs was significantly higher than that in SGPs and AGPs (p < 0.05). Overall, our results indicated the importance of bamboo shoots as a major source of protein in GGPs' diet, which can effectively compensate for the certain nutritional loss caused by the reduction in bamboo intake. Age-related changes in bacterial abundance have an effect on specific nutrient apparent digestibility in the gut of GPs. The data presented in this study serve as a useful reference for nutritional management in different ages of GPs under healthy conditions. [ABSTRACT FROM AUTHOR]