VETERINARSKI ARHIV 68 (4), 127-133, 1998

ISSN 0372-5480
Printed in Croatia

Electrolyte, enzyme, protein and metabolite levels in the blood plasma of the wild adult African giant rat (Cricetomys gambianus, Waterhouse)

Jonhson O. Oyewale¹*, Olusola A. Oke², Funsho O. Olayemi¹ and Ajibola O. Ogunsanmi³

¹Department of Veterinary Physiology and Pharmacology, University of Ibadan, Ibadan, Nigeria

²Department of Veterinary Anatomy, University of Ibadan, Ibadan, Nigeria

³Department of Wildlife and Fisheries Management, University of Ibadan, Ibadan, Nigeria

* Contact address:
Dr. Johnson O. Oyewale,
Department of Veterinary Pharysiology and Phmacology, University of Ibadan, Ibadan, Nigeria,
Phone: 234 2 81 03 168; Fax: 234 2 81 03 118
E-mail: library@kdl.ui.edu.ng

OYEWALE, J. O., O. A. OKE, F. O. OLAYEMI, A. O. OGUNSANMI: Electrolyte, enzyme, protein and metabolite levels in the plasma of the wild adult African giant rat (Cricetomys gambianus, Waterhouse). Vet. arhiv 68, 127-133, 1998.

ABSTRACT

As part of the ongoing studies on the blood constituents of wild adult African giant rats (Cricetomys gambianus, Waterhouse), the plasma levels of electrolytes, enzymes, proteins and metabolites were determined. Plasma electrolyte values were: sodium = 96.25-97.11 mmol/l; potassium = 5.34-5.54 mmol/l; chloride = 80.00-83.20 mmol/l; bicarbonate = 10.33-10.60 mmol/l; calcium = 2.48-2.86 mg/dl. Plasma enzyme values were: alkaline phosphatase = 99.80-112.22 i.u/l; glutamic-oxaloacetic transaminase = 24.89-29.00 i.u/l; glutamic-pyruvic transaminase = 14.89-16.80 i.u/1. Plasma protein and metabolite values were: total protein = 5.82-5.86 g/dl; albumin = 2.69-2.72 g/dl; globulin = 3.10-3.17 g/dl; urea = 11.67-11.80 mg/dl; creatinine = 0.59-0.60 mg/dl. No significant sex differences were evident in any of these values. The values are compared with the data reported in the same tropical environment in humans and other mammalian species.

Key words: plasma electrolytes, enzymes, protein, African giant rat, Cricetomys gambianus

Introduction

In a previous study (OYEWALE et al., 1998), the haematological values of the wild adult African giant rat (Cricetomys gambianus, Waterhouse) were determined. The results revealed that erythrocyte osmotic fragility was significantly higher, but total white blood cell count was significantly lower, in females than in males. The values of packed cell volume and haemoglobin were significantly higher than in pangolins, cattle, sheep and goats, but were similar to the values in humans in the same tropical environment. The total white blood cell count was significantly lower than in cattle, sheep and goats, but was significantly higher than in pangolins, and similar to the count in humans. The present investigation, which is a continuation of that study, examines the levels of electrolytes, enzymes, proteins and metabolites in the blood plasma of wild adult male and female African giant rats.

Materials and methods

Adult African giant rats (Cricetomys gambianus, Waterhouse) captured from the wild were kept in the animal house of the Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria. They were supplied with a diet of commercially available mouse cubes (21% protein, 3.5% fat, 6% fibre, 0.8% phosphorus, 0.8% calcium; Ladokun Feeds Limited, Ibadan, Nigeria), and water ad libitum. Their food was supplemented with palm kernel fruits.

Six weeks after capture, 9 female and 5 male giant rats were active and eating, showing no signs of illness or of visible or palpable abnormalities. Each animal was anaesthetised using ether, and blood was collected from the orbital sinus into a bottle containing ethylene diamine tetraacetic acid (EDTA, 2 mg/ml of blood). The blood samples were centrifuged at 3,000 g for 10 minutes to obtain plasma.

Sodium and potassium concentrations of the plasma were determined by standard flame photometry, chloride by the method of SCHALES and SCHALES (1941), and calcium and bicarbonate according to TORO and ACKERMANN (1975). Activities of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase were determined colorimetrically according to MOHUN and COOK (1957). Alkaline phosphatase was determined according to the method of KING and ARMSTRONG (1934).

Total protein was determined using the biuret method (REINHOLD, 1953), and albumin by the method of DOUMAS et al. (1971). Globulin was calculated by subtracting albumin from total protein. Urea and creatinine were determined according to HARRISON (1947).

The results were statistically evaluated using Student's t-test.

Results and discussion

Plasma electrolytes and enzymes

Results of plasma electrolyte and enzyme analyses in male and female giant rats are presented in Table 1. No significant sex differences were found in plasma sodium, potassium, calcium, chloride, and bicarbonate levels. Plasma alkaline phosphatase, glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase levels did not also differ significantly between male and female giant rats. These observations are in agreement with similar findings in pangolins (Manis tricuspis) (OYEWALE et al., 1997), mink (Mustela vison) (WEISS et al., 1994) and goats (ODUYE and ADADEVOH, 1976a). However, our findings disagree with those reported in humans (McFARLANE et al., 1970), where males have higher sodium and bicarbonate values than females. The mean calcium value has also been reported to be higher in male sheep (ODUYE and ADADEVOH, 1976b). In cattle, the male has lower sodium and chloride values than the female (ODUYE and FASANMI, 1971). Higher alkaline phosphatase values have been reported in female than in male armadillos (Dasypus novemcinctus) (STROZIER et al., 1971; RAMSEY et al., 1981).

Table 1. Plasma electrolyte and enzyme levels (mean±SD) in male and female African giant rats

Table 2 compares the plasma electrolyte and enzyme values in giant rats with those reported in similar studies in this tropical environment in humans (McFARLANE et al., 1970) and other mammalian species, such as pangolins (Manis tricuspis) (OYEWALE et al., 1997), Nigerian goats (ODUYE and ADADEVOH, 1976a), Nigerian pigs (ENDELEY, 1979), and White Fulani cattle (ODUYE and FASANMI, 1971). Mean sodium level in giant rats was significantly lower (P<0.001) than in pangolins (OYEWALE et al., 1997), goats (ODUYE and ADADEVOH, 1976a), cattle (ODUYE and FASANMI, 1971) and humans (McFARLANE et al., 1970), but was significantly higher (P<0.001) than in pigs (ENDELEY, 1979). The plasma level of potassium in giant rats was significantly higher (P<0.001) than in humans (McFARLANE et al., 1970), goats (ODUYE and ADADEVOH, 1976a) and cattle (ODUYE and FASANMI, 1971), although significantly lower (P<0.001) than in pigs (ENDELEY, 1979) and similar to the value in pangolins (OYEWALE et al., 1997). Giant rats had a significantly lower (P<0.001) plasma chloride value than humans (McFARLANE et al., 1970), pangolins (OYEWALE et al., 1997), goats (ODUYE and ADADEVOH, 1976a) and cattle (ODUYE and FASANMI, 1971). Calcium value in giant rats was significantly lower (P<0.001) than in pangolins (OYEWALE et al., 1997), goats (ODUYE and ADADEVOH, 1976a) and cattle (ODUYE and FASANMI, 1971), and the bicarbonate level was significantly lower (P<0.001) than in humans (McFARLANE et al., 1970).

Alkaline phosphatase level in giant rats was significantly higher (P<0.001) than in pangolins (OYEWALE et al., 1997), goats (ODUYE and ADADEVOH, 1976a) and pigs (ENDEDLEY, 1979). However, the glutamic-oxaloacetic transaminase value was significantly lower in giant rats than in pangolins (P<0.01) (OYEWALE et al., 1997) and goats (P<0.001) (ODUYE and ADADEVOH, 1976a). The glutamic-pyruvic transaminase value in giant rats was also significantly lower than in goats (P<0.05) (ODUYE and ADADEVOH, 1976a).

Table 2. Comparison of plasma electrolyte and enzyme values (mean±SD) in African giant rats, pangolins, goats, pigs and humans in the same tropical environment

ND=Not determined

Plasma proteins and metabolites

The mean values of plasma proteins and metabolites in male and female giant rats are shown in Table 3. No significant sex differences were evident in the values of total proteins, albumin, globulin, albumin/globulin ratio, urea and creatinine. These findings are similar to the observations in mink (Mustela vison) (WEISS et al., 1994), where total protein, albumin and creatinine values did not differ significantly between sexes. KARESH et al. (1995) also found no significant sex differences in the values of creatinine, urea, total protein, albumin and globulin in 5 species of duikers (Cephalophus species) in Zaire. In contrast, the male sheep has higher total protein (OTESILE and KASALI, 1992) and urea values (ODUYE and ADADEVOH, 1976b) than the female. In cattle, total protein and globulin values have been found to be higher in females than in males (ODUYE and FASANMI, 1971).

Table 3. Plasma protein and metabolite levels (mean±SD) in male and female African giant rats

Table 4 presents a comparison of the plasma protein and metabolite values in giant rats with the values reported in humans (McFARLANE et al., 1970) and some other mammalian species, such as pangolins (Manis tricuspis) (OYEWALE et al., 1997), Nigerian goats (ODUYE and ADADEVOH, 1976a), White Fulani cattle (ODUYE and FASANMI, 1971) and buffaloes (Bob bubalis) (OLUSANYA et al., 1976) in the same tropical environment. The mean total protein value in giant rats was significantly lower (P<0.001) than in goats (ODUYE and ADADEVOH, 1976a), cattle (ODUYE and FASANMI, 1971) and buffaloes (OLUSANYA et al., 1997). Giant rats had a mean albumin value similar to those reported in cattle (ODUYE and FASANMI, 1971), goats (ODUYE and ADADEVOH, 1976a) and pangolins (OYEWALE et al., 1997), although significantly lower (P>0.001) than in buffaloes (OLUSANYA et al., 1976). The globulin value in giant rats was significantly lower (P<0.001) than in cattle (ODUYE and FASANMI, 1971) and buffaloes (OLUSANYA et al., 1976), but was similar to those reported in goats (ODUYE and ADADEVOH, 1976a) and pangolins (OYEWALE et al., 1997). The urea value was significantly lower in giant rats than in pangolins (P<0.01) (OYEWALE et al., 1997), goats (P<0.001) (ODUYE and ADADEVOH, 1976a) and humans (P<0.001) (McFARLANE et al., 1970). However, the mean urea value found in Zaire in the free-ranging duiker (Cephalophus dorsalis), 11.30±4.8 mg/dl (KARESH et al., 1995) was very close to our value (11.71±2.30 mg/dl) in giant rats.

Table 4. Comparison of plasma protein and metabolite levels in African giant rats, pangolins, goats, cattle, humans and buffaloes in the same tropical environment

ND=Not determined

Although there may be differences in nutrition, environment and level of activity between giant rats in the wild and in captivity, we believe that the results of the present study can be used as a guideline for health evaluation of wild and captive adult giant rats. However, the data presented in this study may not be applicable to immature giant rats.

References

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Received: 13 February 1998
Accepted: 15 June 1998

OYEWALE, J. O., O. A. OKE, F. O. OLAYEMI, A. O. OGUNSANMI: Razina elektrolita, enzima, bjelancevina i metabolita u krvnoj plazmi odraslog divljeg africkog divovskog stakora (Cricetomys gambianus, Waterhouse). Vet. arhiv 68, 127-133, 1998.

SAZETAK

Utvrdivane su razine elektrolita, enzima, bjelancevina i metabolita u plazmi divljeg odraslog africkog divovskog štakora (Cricetomys gambianus, Waterhouse), a kao dio studije o sastavu krvi te vrste. Vrijednosti elektrolita plazme bile su: natrij = 96,25-97,11 mmol/l; kalij = 5,34-5,54 mmol/l; klorid = 80,00-83,20 mmol/l; bikarbonati = 10,33-10,60 mmol/l; kalcij = 2,48-2,86 mg/dl. Vrijednosti enzima plazme bile su: alkalna fosfataza = 99,80-112,22 i.u/l; glutaminska-oksalacetat transaminaza = 24,89-29,00 i.u/l; glutaminska-piruvat transaminaza = 14,89-16,80 i.u/l. Vrijednosti plazminih bjelancevina i metabolita bile su: ukupne bjelancevine = 5,82-5,86 g/dl; albumin = 2,69-2,72 g/dl; globulin = 3,10-3,17 g/dl; mokracevina = 11,67-11,80 mg/dl; kreatinin = 0,59-0,60 mg/dl. Ni za jednu od ovih vrijednosti nisu utvrdene znacajne razlike s obzirom na spol. Vrijednosti su usporedene s objavljenim podacima za ljude i druge vrste sisavaca u istom tropskom okolišu.

Kljucne rijeci: elektroliti krvne plazme, enzimi, bjelancevine, africki divovski stakor, Cricetomys gambianus