Morphometry of cryopreserved organs from the gastrointestinal system of squirrel monkeys (Saimiri sciureus, Linnaeus, 1758) for improvement of management

Abstract

Background Nonhuman primates (NHPs) are fundamental for countless types of research and their phylogenetic similarities with humans make them valuable biomodels. Saimiri (squirrel monkeys) is the New World simian genus that is most widely used in research; however, little is known about the morphology of the gastrointestinal tract (GIT) of these animals. Methods The morphological and topographical aspects of GIT organs from 14 previously frozen carcasses of captive squirrel monkeys (Saimiri sciureus) were described as a means for refining clinical and laboratory diagnoses, with the aim of providing a basis for clinical assessments and animal management. The carcasses were gradually thawed, macroscopically evaluated for their appearance, measured, weighed, photographed, and necropsied. The characteristics of all the GIT organs (main and accessories) were evaluated, with measurement of the dimensions and description of the shape, consistency, and color of each one. Results The stomach of squirrel monkeys is simple and of non‐compartmentalized type and the cecum does not have numerous folds, compared with other species. These characteristics are compatible with omnivorous simian species with no adaptive digestive specialization for the food fermentation process. Significant correlations were found between the weights of the carcass and GIT (p < .05); carcass and tongue (0.83; p < .01); and liver and right salivary gland (0.83; p < .01). It was also observed that the animals showed good body score conformation and GIT organs in good condition, which indicated that their nutritional management had been adequate. Regarding the correlations found among the organs: (i) squirrel monkeys with heavier carcasses had better‐developed GIT with greater food storage capacity; (ii) the bigger the animal was, the greater its overall muscle development was, including that of the tongue, which would enable intensification of its feeding activity; and (iii) the measurements of the esophagus, small and large intestines, pancreas, and salivary glands were not sex‐dependent in Saimiri sciureus. Conclusions Previously cryopreserved carcasses of squirrel monkeys can be used for gastrointestinal system studies, with the potential to make clinical, zootechnical, management, and scientific contributions.

Comparative Investigation of Tongue and Esophagus Morphometry in Swiss Albino and Balb-c Mice

“…It is thought that these correlations may be very useful in revealing sexual dimorphism features in mice and in various clinical application areas. Andrade et al (2023) reported in their study on squirrel monkeys (Saimiri sciureus Linnaeus, 1758) that the length measurements of the tongue and esophagus were 3.0 cm and 12.7 cm, respectively, in males. Additionally, in the same study, they calculated the weight of the tongue as 2.2 g in males and 1.9 g in females.…”

“…In general, numerous studies have been conducted to determine the anatomical, morphological, and morphometric characteristics of the other digestive system organs, including the tongue and esophagus concerning sexual dimorphism in other animals as well as laboratory animals (Yıldız et al, 2001;Walters et al, 2014;Igado et al, 2015;Gırgırı et al, 2015;Sahd et al, 2017;Bełżecki et al, 2018;Jaji et al, 2019;Ayırtır Başdinç, 2023;Andrade et al, 2023). When examining the morphometric measurement values in our study, it was seen that all measurement values obtained from both Swiss Albino and Balb-c mice were higher in males compared to females.…”

“…In studies aimed at determining the morphometric and morphological characteristics of gastrointestinal system organs, it has been observed that there is predominantly a positive correlation between external measurement values in animals (such as body weight) and morphometric data of the organs (Walters et al, 2014;Sahd et al, 2016;Bełżecki et al, 2018). However, in studies conducted on morphometric measurements of the tongue and esophagus, alongside positive correlations between these measurements and both external body measurements and other gastrointestinal system organs, negative correlations have also been identified et al, Andrade et al, 2023). In this study, considering the sexual dimorphism characteristics of both mice breeds, it was observed that the statistically significant measurements between the morphometric data of the tongue and esophagus were mostly positive correlations.…”