Introduction

Livestock sector plays an important role in Indian economy and is an important sub-sector of Indian Agriculture. It helps to improve food and nutritional security by providing nutrient rich food products; while on the other hand, it generates income and employment and gives cushioning effect against crop failure (Kumar et al., 2008). Gujarat is one of the leading states contributing noticeable share in rapidly growing livestock sector of India. Camel is one important component of this livestock sector of Gujarat. Gujarat possesses two breeds of Camel i.e. Kutchi and Kharai (a recently recognized breed); among which Kutchi breed is inhabitant of Kutch and Banaskantha, the dry and semi-arid districts of north Gujarat. It is primarily reared for carting/draft, agricultural operation and transportation in addition to the secondary utility of hair and milk production (Saini et al., 2006). However, the milk yield and composition varies across the length of lactation stage. As the mammary gland secretory cells utilize 80% of the blood metabolites for milk synthesis during lactation, therefore it is imperative to study biochemical constituents during different stages (Piccione et al., 2009), which act as important indicators of the metabolic activity in lactating animals (Karapehlivan et al., 2007). Accordingly, the present study was undertaken to study the variation in blood metabolites during different lactation stages viz. early lactation (1-3 months), mid lactation (4-6 months) and late lactation (≥ 7 months) of Kutchi camel.

Materials and Methods

Location of Study

The present study was carried out in the Department of Physiology and Biochemistry, College of Veterinary Science and Animal Husbandry, Sardarkrushinagar Dantiwada Agricultural University (SDAU), Sardarkrushinagar, Gujarat in collaboration with Camel Breeding Farm, Dhori (Kutch, Gujarat).

Selection and Grouping of Experimental Animals

A total of 30 clinically healthy female Kutchi camels (Camelus dromedarius) were randomly selected from the herd maintained at Camel Breeding Farm, Dhori (Kutch, Gujarat). These animals were categorized into three groups based on their stage of lactation: Early lactation (1-3 months), Mid-lactation (4-6 months) and Late Lactation (≥ 7 months). The average body weight of the animals was about 500 kg with average milk yield of 4-5 kg per day per animal. The selected animals were supposed to be free of endoparasites as anthelmintics are regularly fed to the animals reared at the Camel Breeding Farm, Dhori (Kutch, Gujarat) and were maintained following standard farm practices. All the camels are left free to graze in the open desert. All the animals were clinically healthy with no physical deformities. The health status of the selected animals was regularly evaluated based on behaviour, rectal temperature, pulse rate, respiratory rate and faecal consistency during the study period. The animals were also examined for parasites and deworming of the animals was done regularly.

Blood Sample Collection and Serum Separation

Blood samples were collected during February and March month, which is considered to offer thermo-comfort zone for the animals. The whole blood samples were collected and harvested for serum using VACUETTE^® Z Serum Clot Activator tubes of 9 ml capacity (Greiner Bio-One GmbH, Austria). After centrifugation, clear serum samples were collected in sterile screw tubes of 5ml capacity (CITOTEST^TM, China) and stored at -20^oC temperature till analyzed.

Biochemical Analysis

Estimation of biochemical parameters of the blood samples were carried out through using of ready to use kits. The kits for estimation of glucose, total bilirubin, total cholesterol, creatinine, blood urea nitrogen were procured from Agappe Diagnostics Ltd., Kerala, India. The data generated on enzymatic profile were analyzed statistically using Duncan test by sigma stat software (Snedector and Cochran, 1994).

Results and Discussion

The observed mean values of different biochemical parameters during different stages of lactation in Kutchi camels are presented in Table 1.

Table 1: Blood metabolites during different stages of lactation in Kutchi camels

Means with different superscript within a row differs significantly (p < 0.05) from each other

The blood glucose level (mg/dl) recorded during different stages of lactation in Kutchi camels were 87.66±1.87, 94.00±1.56 and 98.66±1.09 in early lactation, mid lactation and late lactation, respectively. Result showed that, there was significantly (p < 0.05) increase in the blood glucose level from early to mid and mid to late lactation. The concentration of glucose found in the present study is in agreement with the values reported by previous scientists (Ayuob et al., 2003; Tharwat et al., 2015). In the present study, lowered mean of blood glucose concentrations in early stage of lactation may be due to large amount of blood glucose with drawl by the mammary gland for the synthesis of milk lactose (Nale, 2003). It is reported that lactose synthesis and milk yield show a linear positive correlation with glucose uptake and thus the lactose synthesis potential is accompanied by greater glucose uptake by lactating mammary gland and subsequent reduction in blood glucose levels (Afshar and Fathi, 2012). However, this observation is on the contrary to the finding of Saeed et al. (2009) who reported lower glucose concentration in pregnant camels which may be due to different physiological state.

The values for the serum total bilirubin (Tbi) (mg/dl) obtained in this study were 0.77±0.05, 1.30±0.12 and 1.02±0.07 during early, mid and late lactation, respectively. The result indicated significantly (p < 0.05) higher total bilirubin in mid and lactation as compared to early lactation. This may be due to intensive postpartal lipid mobilization and ketogenesis during the course of lactation which provokes a series of compensatory metabolic processes with changes in blood bilirubin level (Cincović et al., 2012). Furthermore, as the excretory function of hepatocytes is reduced, the blood concentrations of total bilirubin is generally increased (Bobe et al., 2004) as lactation advances.

The result of the present study showed that the Mean ± S.E. values (mg/dl) of total cholesterol concentration during early lactation, mid lactation and late lactation were 92.99±2.68, 68.22±3.58 and 45.88±3.05, respectively. The observation of this study is in corroboration with reports of Saeed et al. (2009). Cholesterol acts as the most important indicators of energy status of ruminants along-with glucose (Pechová and Pavlata, 2005). Highest (p < 0.05) cholesterol concentration was found during early lactation which then followed decreasing trend. The concentration of cholesterol is significantly affected by the physiological status, especially during lactation. The trend of the cholesterol level in the present study may be due to endocrine profiles change with simultaneous changes in both the anatomical and biochemical organization of adipose tissue which favor increase lipid reserves in mammals to allow rapid and substantial mobilization of fat following parturition and during early lactation (Roche et al., 2009) which is reflected as higher cholesterol level during early lactation.

Creatinine level (mg/dl) in early lactation, mid lactation and late lactation in the present study were 1.42±0.01, 1.31±0.02 and 1.24±0.01, respectively. The values of creatinine level in present study is agreed with the values recorded by Ayuob et al. (2003) and observed by Omer et al. (2006) in lactating Sudanese camels. The creatinine level in early lactation was significantly (p < 0.05) higher than mid lactation and late lactation. It is reported that during the late gestation, the mother assumes the load of organic waste of the newborn for the foetal maternal circulation (Ferrell, 1991) and represents higher creatinine level during early lactation as compared to mid and late lactation. Furthermore, increase in creatinine level at the early stage of lactation may be also due to uterine involution and myometrial protein degradation (Bell et al., 2000). Blood urea nitrogen (BUN) during different stages of lactation in Kutchi camels were 23.13±0.71 (early lactation), 18.71±0.61 (mid lactation) and 16.76±0.46 (late lactation). The BUN values observed in present study were within the range determined by Saeed et al. (2009) and Tharwat et al. (2015). BUN concentration in late lactation was significantly (p < 0.05) lower than early lactation and mid lactation. It may be due to more drainage of nitrogen in terms of urea through urine and milk, as lactation advances (Roy et al., 2003). As blood samples were collected during thermo-neutral season, hence it may be assumed that season did not influence in the changes of blood metabolites and the variations shown in different metabolites are due to different stages of lactation.

Conclusion

Determination of biochemical metabolites in blood serum can provide valuable information regarding nutrition and physiological status of dairy animals in relation to stage of lactation. The lactation phases affect significantly the metabolic profile and so the variation recorded during different physiological phases is expected. The transition from gestation to lactation is a period of great metabolic stress for dairy camels like other livestock animals. However, the values of serum different biochemical parameters are in the accepted range of reference values. The results of the present study may hopefully contribute to diagnostics and/or evaluation of herds from the view point of biochemical and patho-physiological processes.

Acknowledgements

The authors would like to thank the Dean, College of Veterinary Sciences & AH, SDAU, Gujarat for providing necessary laboratory facilities and financial assistances to carry out the research work smoothly.

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