Effect of Diarrhea on Hematocrit and Serum Biochemical Profile in Foals

This study was conducted at various public and private sector veterinary hospitals as well as equine stud farms in and around Lahore district, Pakistan. A total of 105 foals (n = 35 horse foals, n = 35 donkey foals and n = 35 mule foals) which were affected clinically with diarrhea regardless of the etiology and 12 apparently healthy foals (n = 4 horse foals, n = 4 donkey foals and n = 4 mule foals) were selected as control group for this study.

Peripheral blood was collected aseptically from puncture of jugular vein into 5 mL vacuum plain tubes and 5 mL vacuum tubes containing ethylene diamine tetraacetic acid (EDTA) separately. Plain tubes were kept undisturbed for 30 min to clot the blood samples. Plain tubes were centrifuged for 12 min at 3,000 rpm after incubation (37oC, 60 min). Serum was withdrawn into 1.5ml Eppendorf tubes and frozen at −80oC for later biochemical analysis. Tubes containing EDTA were used for determination of PCV using microhematocrit method. The serum samples were analyzed by atomic absorption spectrophotometer. Macro minerals (calcium, potassium and sodium) and trace elements (copper and iron), and ultra-trace elements (lithium) were estimated as described by Basaki et al. (2012), Tajik and Nazifi (2013) and Akhter et al. (2007) at Quality Operations Laboratory, UVAS, Lahore. The values were compared with references values.

Data obtained from comparative study of two groups (i.e. diarrheic and healthy foals) on hematocrit and serum biochemical profile were analyzed by student t-test using IBM® SPSS (Statistical Product and Service Solutions) Statistics® version 22.0. The probability (p) value less than 0.05 were considered significant.

Table I.- Effect of diarrhea on the average packed cell volume, serum macro minerals, trace and ultratrace elements in Foals.

* Significant difference p < 0.05.

PCV in all diarrheic foals of horses, donkey and mules was significantly higher (p-value<0.05) compared to their healthy counterparts. Average PCV (%) levels in diarrheic foals of horses, donkeys, and mules were revealed 56, 57, and 59, respectively (Table I). PCV was slightly higher in mule foals, followed by donkey and horse foals. Concentration of sodium, potassium, calcium, copper, iron and lithium were evaluated in the serum sample of diarrheic as well as control group of equine foals. Serum sodium, copper, iron and lithium levels in diarrheic foals of all species in the study were decreased significantly (p< 0.05) when matched with healthy ones. The serum potassium values were however significantly increased (p< 0.05) in all diarrheic foals comparing with healthy foals.

Increased PCV in all diarrheic foals compared to healthy foals was consistent with the findings of Frederick et al. (2009), who reported increased PCV in non-survivor compared to survivor diarrheic foals. A case of an adult horse with acute diarrhea having high PCV stated by Oliver and Stampfli (2006) also confirmed these results. PCV increases in diarrhea due to the loss of the water from plasma consequently cellular part of blood converts to major portion.

Keeping in view the control group, reduced serum sodium concentrations in all diarrheic foals were in agreement with previous studies (Oliver and Stampfli, 2006; Gomez et al., 2013), which disclosed hyponatremia in adult horses with acute diarrhea. Diarrhea leads to loss of isotonic fluid (hypovolemia). Excessive loss of gastrointestinal water, sodium, chloride, and bicarbonate diminish the extracellular portion of these electrolytes. Kidney response of fluid loss is to accelerate proximal tubule’s reabsorption sodium, chloride, bicarbonate and water. Normal plasma sodium to chloride (1.4:1) is decreased so it is called hyperchloremic metabolic acidosis. Sodium reabsorption results in sodium delivery at distal tubule for H+ exchange exacerbating the acidosis (Wilson and Green, 1986).

Higher serum potassium values in all three categories of diarrheic foals supported the results of case report about diarrhea in non-suckling horses (Wilson and Green, 1986). Grinberg et al. (2009) reported hyperkalemia in hospitalized foals affected with cryptosporidiosis are also in close agreement with this study. Contradictory to this, hypokalemia were reported by various authors (Oliver and Stampfli, 2006; Navarro et al., 2005; Gomez et al., 2013). Underlying whole body potassium deficit might be the reason of hypokalemia in previous studies.

Consistent low serum calcium levels in all diarrheic foals during the study coincided with earlier work (Navarro et al., 2005) in which both total and ionized calcium levels were decreased in colic horses with diarrhea. Another study revealed lower total, ionized and adjusted ionized calcium levels in horses with diarrhea (Kolk et al., 2002) are also accorded with our results. Likewise, Dart et al. (1992) also described lower serum ionized calcium concentration in horses with surgical managed gastrointestinal disease. Previously, other studies also stated hypocalcemia in diarrheic calves (Cabello et al., 1977; Groutides and Michell, 1990; Michell et al., 1992). Possible reasons of hypocalcemia might be alterations in the levels of ionized calcium due to modifications in blood pH and plasma albumin levels, infection, inadequate food intake, and intravenous fluid therapy without calcium supplementation, and ileus (Navarro et al., 2005).

Decreased serum concentration of copper and zinc in diarrheic people (Kilic et al., 2003; Arora et al., 2006) were congruent to hypocupremia of present study in diarrheic foals. Copper is required for hemoglobin formation, iron transport, and ceruloplasmin synthesis. Ceruloplasmin (ferroxidase) is a glycoprotein enzyme produced in the liver and essential in iron oxidation, permitting it to bind with the iron transport protein transferrin (Jain, 1993). Copper is generally thought to be readily absorbed in the upper gastrointestinal tract including stomach, duodenum and jejunum (Sternlieb, 1967). Hypocupremia may be inherited and acquired copper deficiency. The causes of latter include dietary deficiency, protein deficiency, high amount of iron, zinc or ascorbic acid, diarrhea, inflammatory bowel disease, short bowel syndrome, stoma, fistula, and celiac disease in humans (Sandstead, 1982; Rodriguez et al., 1985; Spiegel and Willenbucher, 1999). So, it can be concluded that hypocupremia leads to serum iron deficiency consistent with findings of this study. Iron deficiency anemia were reported in children affected with acute gastroenteritis due to Entamoeba histolytica and Giardia lamblia in Gaza (Al-Laham et al., 2015), latter may be cause of diarrhea in our foals. Relation of iron deficiency anemia and celiac disease in was well described which included impaired duodenal mucosal uptake of iron due to reduced surface absorptive area, blood loss due to ulceration and neoplasia, immune-mediated hemolysis, and reduced expression of regulatory proteins involved in iron uptake (Freeman, 2015).

Serum lithium levels in all diarrheic foals were decreased versus healthy foals. Unfortunately, there was no published work on diarrheic effect on lithium body reserves. Lithium is assimilated in the alimentary tract and expelled by urinary system entirely (Schrauzer, 2002; Linakis, 2007; Shahzad et al., 2016). Lithium is distributed in total body water and does not bind to serum proteins (Okusa and Crystal, 1994; Shahzad et al., 2016). Lithium competes with cations, especially Na+, K+, Mg++ and Ca++. It may also interact with ammonia groups (including biogenic amines) (Bunney and Mandell, 1979). It interacts with cyclic-AMP-mediated processes, notably in the kidney, thyroid, and CNS (Ebstein and Belmaker, 1979). It has effects on membranes (i.e., red cell membrane), neurotransmitter systems and serotonin synthesis (Mandell and Knapp, 1976; Rosenthal and Goodwin, 1982). Lithium deficiency may likely be attributed to the lithium-poor nutrition and mothers of the diarrheic foals, not the diarrhea. It was reported in goats that lithium-poor nutrition decreased feed intake in growing youngones, lower birth weight of kids, lesser conception rate, increased abortion rates, delivery of more female kids, decreased milk production, life expectancy and serum enzyme activity (isocitric acid dehydrogenase, malate dehydrogenase, aldolase, and glutamine dehydrogenase), except stress indicator enzyme (creatinine kinase), and skin lesions (Anke et al., 1983, 1991; Mueller et al., 2010).

It can be concluded that diarrhea in foals lead to changes in blood hematocrit, serum minerals, trace elements and ultra-trace elements. With diarrhea there is an increase in PCV% and concentration of potassium, while the concentration of sodium, calcium, copper, iron and lithium decreased.

The authors are grateful to Higher Education Commission, Pakistan and Medicine Laboratory, University of Veterinary and Animal Sciences, Lahore for the provision of laboratory and technical assistance for the smooth run of this research study.

Authors have declared no conflict of interest.