Study of the Relationship Between Natural Mating Expression and Intestinal Resistance Genes in Captive Adult Giant Pandas

A growing body of evidence indicates that the gut microbiota has a role in the mating preference process in mammals. This likely occurs through the modulation of various mating signals induced by symbiotic bacteria, thereby leading to variations in mating behavior. Given that giant pandas are solitary wild animals that rely on chemical signals for mate selection, it is relevant to explore whether the mating behavior of giant pandas is also affected by the gut microbiota. We hypothesize that antibiotic treatment-induced residual antibiotic resistance genes in captive giant pandas may disrupt intestinal microbiota homeostasis, diminish the abundance of beneficial microorganisms involved in short-chain fatty acid synthesis, and consequently impair nervous system function via the gut–brain axis. The ensuing physiological stress is likely to suppress innate mating behavior and compromise pheromone synthesis, thereby reducing an individual’s attractiveness to potential mates. To answer this question, we utilize fecal metagenomics technology to analyze the differences in gut microbes and antibiotic resistance genes (ARGs) between captive male adult giant pandas displaying natural versus non-natural mating behavior. The research findings suggest that, when compared with captive adult male giant pandas demonstrating natural mating behavior, those with non-natural mating behavior exhibit a significantly reduction in the abundance of beneficial gut microorganisms (s_Clostridium sp. and f_Ruminococcaceae) (p < 0.05). Concurrently, there is a significantly increase in the observed resistance genes tetO and mgtA, which are mainly associated with macrolide and tetracycline resistance (p < 0.05). Furthermore, Kegg functional analysis reveals a significant up-regulation of metabolic pathways related to sensory systems, such as taste and olfactory transduction, in the intestines of captive adult male giant pandas showing natural mating behavior. These results imply that changes in the abundance of gut microbiota and ARGs are correlated with the manifestation of natural mating behavior in captive adult male giant pandas. Consequently, to improve the success rate of natural reproduction within the male giant panda populations in captive environments, it is advisable to administer antibiotics judiciously and closely monitor the composition of beneficial bacteria in their gut microbiota. The findings of this study provide novel perspectives on the mechanisms by which captive conditions affect the decline in natural mating behavior observed in adult male giant pandas.