Analysis of the morphological structure and metabolic characteristics of Moniezia in sheep.

Both Moniezia benedeni (M. benedeni) and Moniezia expansa (M. expansa) can parasitize the small intestine of ruminants, posing a significant threat to the health of young animals. In this study, morphological methods were first employed to compare the morphological characteristics of the two species, followed by the application of gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) techniques for analyzing their metabolic differences. The results showed that the two species were similar in appearance, with a small, subspherical scolex equipped with four suckers and lacking a rostellum and hooks. The key differences between M. benedeni and M. expansa lie in their eggs and interproglottidal glands: the former has quadrangular eggs with band-like distributed interproglottidal glands, while the latter has triangular eggs with saccular-arranged interproglottidal glands. A total of 187 differential metabolites were identified between the two species. Among these metabolites, 105 were upregulated in M. benedeni, which were mainly involved in metabolic pathways such as taurine and hypotaurine metabolism and sulfur metabolism; these pathways exhibited considerable potential in mediating stress resistance responses. In contrast, 82 metabolites were highly expressed in M. expansa, which were primarily associated with metabolic pathways including nicotinic acid and nicotinamide metabolism and purine metabolism; these pathways were more efficient in utilizing nutrients from the host. This study provides a foundation for further exploring the parasitic and metabolic mechanisms of these two tapeworm species, as well as for identifying the metabolic molecules that modulate the immune perception and response of sheep.