To our knowledge this is the first report about the haematological and serum biochemical parameters in Chinese water deer. This study is a comprehensive survey on the 81 samples of Chinese water deer so far examined. The data has been used to calculate reference values, and to analyze them by sex and location.
The PLT in the males were much higher than that in the females without significant difference. However Parmar et al. (2017) found opposite result in Mehsana Goat (Capra hircus), mild higher in female goats,and slightly increased with age, which in the over 1 year’s were higher than in the under 1 year’s without explain [22] (Additional file 2). While the PLT values found in the juveniles are significantly higher than the adults for mouflon (Ovis ammon), Persian fallow deer (Dama mesopotamica) and Red deer, which might contribute to stronger haematopoietic capacity in juveniles [23,24,25]. We found the PLT and body mass showed significant positive correlation in the males (ρ = 0.528, p = 0.00012), and negative correlation in the females (ρ = − 0.478, p = 0.084) in Fig. 1. This may be the reason for males exhibited much higher PLT values than the females.
In this study, CK was found in myocardium and skeletal muscle and sensitive to muscle damage [26]. It exhibited much higher in the female Chinese water deer, but it had found the opposite tendency in fallow deer (Dama dama L.) and rusa deer (Rusa timorensis) [15, 27]. The CK value was found increasing rapidly when physical capture instead of chemical capture in red deer [13, 28]. Compared to fallow deer and rusa deer, the stress response of female was stronger in Chinese water deer [15, 27]. In addition, CK, lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were raised when transportation than capture, might be caused by increased stress for mouflon [23]. Beside CK, LDH, AST, and ALT all showed higher in female.
In this study, the ALP value in female Chinese water deer was only half of that in rusa deer ALP activity in blood is associated with the osteoblastic activity and also an index of skeletal and antler growth [15]. The ALP value was lower in Chinese water deer, but higher in rusa deer, and the gap was especially bigger in males [15]. Rusa deer have to support antlers develop, but Chinese water deer do not. ALP activity is associated with the osteoblastic activity and also an index of skeletal and antler growth [15].
There are several sex related differences significantly between the values for the males and the females. The higher for ALB, MCV, PCV and MCH obtained in the females (Table 2). The ALB, as a group of serum protein, may be influenced by nutrient condition in genus (Odocoileus) [29]. As was previously shown that our results found no correlation between body mass and ALB values Table 3). Higher body mass and protein intake may cause serum protein differences in bucks [27], but the females (14.05 kg) were heavier than males (12.74 kg) in the Chinese water deer we tested (Fig. 2). The result obtained by the previous study, the females 16.25 ± 1.77Kg) were heavier than the males (15.88 ± 1.44Kg) [16]. The studies on rusa deer, sika deer (Cervus nippon yesoensis) and grey-brocket deer (Mazama gouazoubira) found low MCV values in males as well, but there were no significant differences between the males and the females [30,31,32]. Besides cervid, other animals like cattle was found low MCV values in males [33]. However, in rusa deer, HO et al. (2018) found the MCV values for the females was significantly higher than the males [15]. PCV value for the females were higher than which for the males in grey-brocket deer, rusa deer, and fallow deer, respectively [24, 31, 32]. The high PCV values also found in goats (Capra aegagrus hircus) [34]. The MCV is the ratio of PCV to RBC. Although the RBC was no significant differences between two sexes, RBC in the females was slightly higher than those in the males. The differences observed in the MCV and PCV might be influenced by body conditions. The female Chinese water deer were heavier than the males (Fig. 2). Furthermore, the males in the Persian fallow deer had significantly higher MCH value [24]. We speculated that PCV and MCV increases were due to large oxygen consumption in females. Another possibility was that the tested females’ body mass was heavier than the males (Fig. 2). The females may have a higher oxygen demand, which would lead to an increase in the values for PCV and MCV.
When investigating the difference between the Chinese water deer from two locations, the level of living condition and freedom level were considered. The study by Nina (2004) suggested that location might influence body condition via food resources and living space [27]. In our study, the BUN of the deer from Shanghai were significantly higher than the ones from Zhoushan. BUN was affected by high protein food catabolism and levels of rumen degradable proteins in a Red deer study [35]. We speculated that these differences in BUN were related to differences in body mass caused by nutrition levels (p = 0.012) (Fig. 3). The deer in Zhoushan feed on soybean meal and some farmland green materials, while the deer in Shanghai feed on soybean meal and ate grass freely, which may be the reason for the increase of the BUN value in Shanghai.