Saliva Crystallization Occurs in Female Bornean Orangutans (Pongo pygmaeus): Could It Be a New Option for Monitoring of Menstrual Cycle in Captive Great Apes?

Abstract

Saliva crystallization was previously studied in both humans and animals with various results. The study aimed to confirm of the presence of saliva crystallization in female Bornean orangutans (Pongo pygmaeus), to evaluate the quality of samples which were collected from animals and processed by keepers, and to test preliminarily if the saliva crystallization could be connected with menstrual cycle and could serve as a cheap, quick and simple method for the basic monitoring of their reproductive status. The research was carried out from September 2014 to January 2015. Sampling of saliva was done in three female orangutans from three zoological gardens (Dvur Kralove, Usti nad Labem, Bojnice) daily, mostly by tongue prints on glass slides with ground edges or by sampling directly from the mouth using plastic spoons from which the saliva was transferred onto glass slides. Samples were evaluated by light microscopy with ×400 magnification. The quality of the sample and type of crystallization was assessed for two different approaches. In total, 246 samples were evaluated. We confirmed the presence of saliva crystallization in orangutans. The quality of samples was variable however acceptable. Unfortunately, it was impossible to detect exact fertile period in two females. However in one orangutan female, when the crystallization was evaluated by the approach typically used in humans, we discovered that saliva crystallization during the fertile period significantly differed from saliva crystallization in the non-fertile period. This points out the possibility of using saliva crystallization for detection of the fertile period in orangutans. However, further research was recommended.

A novel women's ovulation prediction through salivary ferning using the box counting and deep learning

“…Ovulation detection research related to salivary crystallization patterns to detect estrus in eight female bubalus bubalis buffaloes for three months [4]. Research studying the menstrual cycle of three female bornean orangutans related to the relationship between fertility and salivary crystallization [5]. Another study predicts female ovulation through artificial saliva and human saliva through smartphone-based hardware and microfluidic devices [6], a survey that detects and predicts ovulation by measuring the temperature in the ear canal using an in-ear thermometer every 5 minutes during sleeping hours, then the results are sent to the smartphone for analysis [7].…”

Crystalloscopic analysis in detection of saliva metabolome specialties in elderly people

“…On this basis, it is logical to assume that the diagnostic technology under consideration will be informative in monitoring the involutive transformations of the composition of biological fluids [13]. Their noninvasive control can be carried out by analyzing saliva parameters within the framework of the salivadiagnostics methodology, which has been actively developing in recent decades [14][15][16][17]. In this regard, the aim of the study was to assess the features of saliva crystallization in middle-aged and elderly people.…”

Mucin and salt combination simulate typical fern‐like pattern of buffalo saliva smear at estrus

“…Among these fluids, observing the crystallization patterns of the saliva is a convenient method to employ, because the saliva is available everyday irrespective of different physiological conditions. In the recent years, the salivary crystallization method is becoming popular in monitoring the menstrual cycle of women (Das et al, 2023; Guida et al, 1993; Priya et al, 2020), determining the ideal mating time in female dogs (Pardo‐Carmona et al, 2010), monitoring of the menstrual cycle in wild female Bornean orangutan (Kubátová & Fedorova, 2016) and for determining early pregnancy after artificial insemination (AI) (Skalova et al, 2013) as well as for determining estrus time in cattle (Chavan et al, 2023; History et al, 2015).…”