The mean values of glucose, BUN and creatinine were significantly (P<0.05) higher in the exposed area as compared to control area during both summer and winter seasons (Table 1). The levels of total cholesterol, triglycerides, albumin and globulin were significantly (P<0.05) higher in buffaloes of the exposed area during both the seasons. However, the levels of total cholesterol, triglycerides, albumin and globulin were significantly (P<0.05) lower in buffaloes of the exposed area during the summer as compared to winter season. The levels of total protein, albumin and BUN: Creatinine ratio were significantly (P<0.05) lower in buffaloes of the exposed area as compare to control area and during the summer as compared to winter season in both the areas. The A: G ratio values were significantly (P<0.05) lower in exposed than control area; however, significantly (P<0.05) higher during summer than winter season in both the areas.
Pearson’s correlation between heavy metals and blood biochemical constituents
The Cr, Ni, As and Pb levels showed highly significant (P<0.01) positive correlations with plasma levels of glucose, total cholesterol, creatinine and BUN whereas, they showed highly significant (P<0.01) negative correlations with total protein, albumin and A: G ratio considering both the areas together (Fig 1).
Pearson’s correlation among blood biochemical constituents
Highly significant (P<0.01) positive correlations was observed among plasma levels of glucose, total cholesterol, creatinine and BUN. However, plasma levels of total protein, albumin and A:G ratio showed highly significant (P<0.01) negative correlations with plasma glucose and total cholesterol. Total protein and A: G ratio showed highly significant (P<0.01) negative correlation with creatinine and BUN considering both the areas together (Fig 2).
Pearson’s correlation among plasma enzyme profile
The ALT levels showed highly significant (P<0.01) positive correlation with AST, ALP, CK and GGT. However, AST levels showed highly significant (P<0.01) possitive correlation with CK and GGT considering both the areas together (Fig 3).
Pearson’s correlation between plasma enzymes profile and blood biochemical constituents
Highly significant positive correlation (P<0.01) was observed between plasma levels of ALT, AST, CK, GGT, glucose, total cholesterol, creatinine and BUN (Fig 3). However, plasma levels of total protein and albumin showed significant (P<0.01) negative correlation with all other constituents of metabolic profile studied considering both the areas together
The elevated levels of glucose in metal exposed buffaloes may be due to disturbed glucose metabolism. Arsenic and presence of heavy metals caused beta cell dysfunction may be arrested GLUT4
(Kazi et al., 2009 and
Chen et al., 2009). The glucocorticoid system may be hampered by exposure to heavy metals and this system plays important role in carbohydrate, lipid and protein metabolism
(Kaltreider et al., 2001). The significantly (p<0.01) higher values of total cholesterol and triglycerides in heavy metal exposed buffaloes of current study have been observed by other workers (
Hanan, 2013 and
Vaseem, 2013) may be due to disturbance of lipid metabolism and liver dysfunction. The higher values of these metabolites may be due to changes in lipid metabolism leads to impairment of these crucial pathways
(Javed et al., 2017).
Increased plasma glucose, total cholesterol, triglycerides with decreased plasma protein and albumin in arsenic and lead exposed cattle and mice have been recorded by (
El-Nekeety et al., 2009,
Rana et al., 2010 and
Mohajeri et al., 2014); which is in agreement with the results of the present study.
Baranowska Bosiacka et al., (2000) reported that metals like lead affect numerous enzymes activities thus inhibiting of enzymes of glycolysis, haem and globin synthesis whichinturn influence the metabolism of erythrocytes this fact is in agreement of the present observations
viz; alterations of glucose and total protein in heavy metal exposed buffaloes. High ambient temperature can affect the blood glucose and total cholesterol levels as physiological adaptation mechanisms in dairy animals. The reduced total cholesterol levels during the summer season in both the groups may be due to a reduction in acetate concentration which is the precursor of cholesterol synthesis
(Patel et al., 2016). Significantly (p<0.01) decreased total protein in heavy metals exposed buffaloes may be due to toxic effects of these metals on protein biosynthesis and metal salts reduce the plasma protein content is in agreement with the response observed in fish to heavy metal toxicosis by
(Panigrahi et al., 2016). The reduced levels of total protein, albumin and globulin during the summer season in both the groups in our findings are in accordance with the findings of
(Dangi et al., 2012) i.
e. a significant decrease in total protein, albumin and globulin levels during heat stress in goats. These reduced levels may be due to the heat shock which increases plasma volume and decreases the protein concentrations of plasma. The reduced levels of albumin in the present experiment may be due to the liver dysfunction because of heavy metal toxicosis as albumin is produced by liver, the same observed by
(Javed et al., 2017) in fish exposed to heavy metal loaded water.
It means there may be a source of pollution that influences the metabolic pathways extensively. Total cholesterol, total protein and albumin levels were negatively correlated (p<0.01) with all other metabolic profile parameters studied in heavy metal exposed areas. This may be due to the effect of heavy metals on amino acid anabolism. Heavy metal pollution may have interactive effect on glycolysis, Krebs cycle, nucleic acid metabolism, protein metabolism, pentose phosphate pathway and Fatty acid synthesis, glycogen synthesis
(Strydom et al., 2006). The elevated levels of creatinine and BUN in heavy metal exposed buffaloes may be possibly due to nephrotoxic metals like Pb and As
(Maxie, 1993). The acute heat stress in young and adult Murrah buffaloes induces the changes in blood metabolites and enzymatic reactions; this may be due to adaptations of the animals to changing climate variables and environmental temperature
(Haque et al., 2015, Chaudhary et al., 2015 and
Mazuzullo et al., 2014) which support the present results. The elevated levels of creatinine and BUN in heavy metal exposed buffaloes may be due to lead and arsenic which are nephrotoxic metals
(Maxie, 1993).
In the present study, significantly higher levels of AST, ALP activities and reduced plasma levels of total protein and albumin clearly suggest the hepatic dysfunction in cattle with higher blood metal levels.
Chand et al., (2017) observed the same result in biochemical profile in cattle around industrial effluent contaminated area of kali river of Meerut city. Lead induced hepatic dysfunction in cattle was revealed by the elevated activities of AST, ALP as biomarker for liver functions and synthesis of albumin largely depends on the liver function status
(Flora et al., 2012). The significant increase of AST, ALT activity and decreased albumin is in agreement to those results. In hepatocellular liver diseases due to defective albumin synthesis there may be hypoalbuminemia
(Chand et al., 2017). Increased ALP and GGT activity observed in the buffaloes naturally exposed to arsenic contamination might be due to hepatic dysfunction
(Dash et al., 2016) which is in concurrence with the present study. The elevated activity of GGT is indicative of increased exposure to environmental xenobiotics
(Koenig and seneff, 2015). The increased CK activity in cattle with various muscle injuries may be associated with metal toxicity
(Kaneko et al., 1997 and
Aslani et al., (2012) and
(Dash et al., 2016). Nickel and lead are cardiotoxic metals
(Van Vleet and Ferrans, 1986). Highly significant positive relationship (P<0.01) was observed among the levels of glucose, total cholesterol, triglycerides, creatinine, AST, ALT, ALP, CK and GGT in heavy metal exposed areas. In the present study, all the enzymes analyzed showing seasonal effect during summer. The assessment of enzyme concentrations in plasma or serum interpret the physiological mechanisms as metabolic regulators during stressed conditions and their levels in serum reflects the metabolic activities
(Patel et al., 2016). In contrast to our findings,
Helal et al., (2010) observed the significantly reduced activity of ALP in heat stressed goats. Results similar to the present study were also observed in goats and found that increased levels of ALT during heat stress whereas, in contrast, no changes observed in AST concentrations in these goats
(Sharma et al., 2011). CK activity is higher in the plasma in response to the stress and /muscle damage
(Gwaze et al., 2012).