Comparison of serum chemistry values and serum mineral values between captive and free-ranging elephants in Thailand - D. Tuntasuvan^[14], A. Theeraphan^[15], N. Phoengpong^[16], W. Jitnupong^[17]and G. Lungka^[18]

Abstract

Blood samples of Thai elephants (Elephas maximus indicus) were collected for the study of serum chemistry values and serum mineral values in October 1999. The elephants studied comprised twenty-seven captive elephants (8-55 years old) who were raised in Ayutthaya province (Group 1), and twenty free-ranging elephants (21-60 years old) in Tung Gwean Reforestation Station, Lampang province (Group 2). The mean values of SGOT, ALP, TP and BUN of the elephants in Group 1 were 10.36 ±2.51 U/l, 24.99 ±13.33 U/l, 7.78 ±1.04 g/dl and 7.27 ±2.85 mg/dl, respectively, whereas the mean values of SGOT, ALP, TP and BUN of the elephants in Group 2 were 13.32 ±5.91 U/l, 14.07 ±4.01 U/l, 8.24 ±0.9 g/dl and 13.46 ±2.33 mg/dl, respectively. The mean values of SGOT, ALP and BUN of the elephants in Group 1 and Group 2 were significantly different (p<0.05), but the mean value of TP was not different (p >0.05). Moreover, the mean percent PCV of the elephants in Groups 1 and 2 were significantly different (p<0.05) but they were not different in the case of male and female elephants raised in the same environment.

The mean values of phosphorus (P), calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K) in the serum of the elephants in Group 1 were 5.74 ±0.96 mg/dl, 8.83 ±0.99 mg/dl, 1.96 ±0.26 mg/dl, 113.28 ±24.42 mEq/l and 4.66 ±0.83 mEq/l, respectively. The mean values of P, Ca, Mg, Na and K of the elephants in Group 2 were 6.53 ±1.16 mg/dl, 10.52 ±0.33 mg/dl, 2.58 ±0.44 mg/dl, 89.04 ±10.67 mEq/l and 4.76 ±0.54 mEq/l, respectively. The mean values of P, Ca, Mg and Na of the elephants in Group 1 and 2 were significantly different (p<0.05), but the mean values of K were not different (p >0.05). In Group 2 the mean values of Mg, Na and K in the male elephants were higher than those in the female elephants (p<0.05). However, the P and Ca values for males and females in Groups 1 and 2 were not different (p>0.05). The age of the elephants influenced the levels of Mg and P, but not the levels of Ca, Na and K.

Introduction

In the past, captive Thai elephants (Elephas maximus indicus) were used in the forest industry and usually fed in natural forests. Those traditional jobs have been lost, and most elephants now work in the tourism industry (in shows and tours). Because they are raised in urban areas where their conventional foods are not available, it is assumed that the health of the elephants is likely to be affected by the changed diet. One of the diagnostic tools used for determining health status in animals is serum chemistry values, such as serum enzyme. In addition, minerals play an important role in maintaining the water balance and distribution in the body. The major mineral elements include phosphorus (P), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), sulfur (S) and chloride (Cl). Ca is mostly found in bones and teeth and both Ca and P play important roles in blood clotting and muscle contraction. Mg is found in tissues and blood cells and Na plays an important role in controlling water volume in the body and pH balance (Kaneko, 1989).

The objectives of this study were: (1) to investigate the standard values of serum chemistry and serum minerals of elephants; (2) to compare these values between captive elephants raised in urban areas and free-ranging elephants in forests; and (3) to compare the selected serum chemistry values and serum mineral values of males and females in both groups.

Materials and method

1. Elephant blood samples

Blood samples were collected from the ear veins of two groups of captive Thai elephants in October 1999. These consisted of 27 captive elephants (8 to 55 years old) who were raised in Ayutthaya City, Ayutthaya province (Group 1) and from 20 free-ranging elephants (21 to 60 years old) in Tung Gwean Reforestation Station, Lampang province (Group 2) (see Table 1). The elephant blood was analyzed to determine hematocrit volumes (percent PCV), and selected serum chemistry and mineral values.

Table 1. Number, age and sex of the elephants studied

* = Number of elephants

2. Determination of sera

Sera were determined for serum chemistry values and serum minerals. The selected serum chemistry values to be determined were: (1) aspartate aminotransferase (SGOT) value by Reitman and Frankel method; (2) alkaline phosphatase (ALP) value by p-nitrophenyl phosphate method; (3) total protein (TP) value by hand refractometer; and (4) blood urea nitrogen (BUN) by diacetyl monoxime method (BMLab, 1987). The selected serum mineral values to be determined were P value by Taussky method (Motoi, 1988) using Beckman spectrophotometer DU-64 and Ca, Mg, Na and K values by atomic absorption spectrophotometry (AOAC, 1984). The mean serum chemistry values and serum mineral values of Groups 1 and 2 were compared using students' t test.

Results

By gross examination, most of the elephants in Group 2 were larger and looked healthier than those in Group 1. The mean values of SGOT, ALP, BUN and percent PCV for Group 1 and 2 were significantly different (p<0.05). But the mean values of TP were not different (p>0.05). The mean values of SGOT, BUN and percent PCV of the female elephants in Group 2 were significantly higher than those in Group 1. In contrast, the mean ALP value of the male elephants in Group 1 was significantly higher than that of the male elephants in Group 2 (p<0.05). There was no significant difference in BUN, ALP and TP values for male and female elephants (p>0.05). While the mean percent PCV of Groups 1 and 2 were significantly different (p<0.05), there was no difference in the male and female elephants that were raised in the same environment (Table 2).

Table 2. Serum chemistry values and %PCV of the elephants studied

* = Mean (SD, () = Maximum value and minimum value

In this study, it was found that the mean values of P, Ca, Mg and Na in the free-ranging elephants were significantly higher than those of the captive elephants (p<0.05), but the mean value of K showed no difference (p>0.05). In Group 2, the mean values of Mg, Na and K in the male elephants were higher than those of the female elephants (p<0.05). However, the P and Ca values between the male and female elephants in Group 1 and 2 had no difference (p>0.05) (Table 3). In addition the age of the elephants influenced Mg and P levels, but did not influence Ca, Na and K levels. The mean Mg value of the elephants in Group 1 (12-20 years old) was the highest. This Mg value, however, declined in older elephants, and the same tendency was observed for the P value (Table 4).

Table 3. The values of P, Ca, Mg, Na and K in the serum of the male and female elephants

* = mean (SD, () = maximum value and minimum value

Table 4. The values of P, Ca, Mg, Na and K of the elephants in various age groups

Discussions

The mean values of SGOT, ALP and BUN of the elephants in Groups 1 and 2 showed significant differences (p<0.05), perhaps as a result of different living environments and management conditions. This can be explained as follows. Firstly, the elephants in Group 2 could feed whenever they wanted. Usually elephants spend about 12-19 hours per day on eating (Guy, 1975; Vancuylenberg, 1977). Second, the food sources that the elephants of Group 2 had access to were bamboo (Gigantochloa sp., Bambusa sp.), banana (Musa sp.), mountain grass (Capillipedium sp.), etc. The elephants in Group 1 were fed with banana, cucumber, sugar cane (Saccharum sp.), and long bean (Vigna sp.). Lastly, the Group 1 elephants had less opportunity for physical movement than the Group 2 elephants.

The higher mean values of ALP in some Group 1 elephants indicated an infection caused by Fasciola species.

The findings of this study differed from those of Silvar and Kuruwita (1993). They reported that there were no differences in serum chemistry values in sexes as well as between captive and free-ranging elephants in Sri Lanka. This could have resulted from different examination techniques for serum analysis and also from different elephant samples. The serum chemistry values and percent PCV of the elephants in this study were compared with the studies of Limpoka et al. (1990), Mikota et al. (1998) and Siruntawineti et al. (1995) in Table 5. All their serum samples were collected from captive elephants.

Table 5. The SGOT, ALP, TP, BUN and %PCV values of elephants from various studies

The serum mineral values of captive Thai elephants were first studied by Suthammapinan et al. (1990). Pemayothin et al. (1998a,b) reported that the K and Mg values decreased as the elephants' ages increased. The mean values of P, Ca, Mg and K (except Na) in Group 1 were similar to the values reported by Limpoka et al. (1990) and Pemayothin et al. (1998a,b), who studied captive Thai elephants in the Elephant Conservation Centre, Lampang province. In addition, the mean values of Mg, Na and K in male elephants were significantly higher than female elephants. Pemayothin et al. (1998a, 1998b), Mikota et al. (1998), and Nirmalan and Nair (1969) also reported the same trend as shown in Table 6.

Table 6. The mean values of P, Ca, Mg, Na and K of the elephants from various studies

¹ = Mikota et al., 1998, ² = Suthammapinan et al., 1990, ³ = Pemayothin et al., 1998a, ⁴ = Pemayothin et al., 1998b, NR = no report

Conclusions

The mean values of SGOT, BUN and percent PCV in the free-ranging female elephants were higher than the female captive elephants. In the captive elephants serum Mg, Na, and K values of the males were higher than those of the females. An elephant's age influenced the serum Mg and P values in both groups, but did not influence Ca, Na and K values. The different feeding and management systems for elephants influenced SGOT, ALP, BUN, percent PCV, P, Ca, Mg and Na values. The sex factor had no influence on BUN, ALP and TP values. Thus the range and mean values of SGOT, BUN, ALP, TP, percent PCV, P, Ca, Mg, Na and K on the free-ranging elephants should be considered as standard values for either sex.

Acknowledgements

We would like to thank Mr Sompas Meepan, Dr Preecha Pongkum and Dr Tasanee Chompoochan for their kind co-operation.

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