Metabolic and hematological profiles in mature horses supplemented with different selenium sources and doses1,2

Abstract

This study was conducted to determine the effects of dietary Se source and dose on metabolic and hematological profiles, and their relationships with oxidative status in horses. Twenty-five mature horses were blocked by BW and randomly allocated to 1 of 5 dietary treatments: negative control (CTRL: 0.085 mg of Se/kg of DM), 3 different dietary concentrations of organic Se provided by Se yeast (SY02, SY03, and SY04 containing 0.2, 0.3, and 0.4 mg of total Se/kg of DM, respectively), and 1 positive control provided by sodium selenite (SS03 containing 0.3 mg of total Se/kg of DM). Horses were fed the same basal diet (6 kg of grass hay and 3 kg of concentrate per horse daily) and received their respective treatments for a continuous period of 112 d. Jugular venous blood samples were collected before the morning feed on d 0, 28, 56, 84, and 112. Whole blood was analyzed for hematological profile, and plasma was analyzed for metabolites of energy, protein, and mineral metabolism; enzymatic activities and metabolites related to liver and muscle damage; and markers of inflammatory and oxidative status. Plasma metabolites related to energy, protein, and mineral metabolism, acute phase proteins, and enzyme activities related to hepatocellular, hepatobiliary, and muscle damage were not affected by Se source or dose. There were no differences among treatments in either reactive oxygen metabolites or thiol group concentrations in plasma. However, a linear decrease (P < 0. 01) in plasma total antioxidants was observed with increasing Se yeast supplementation. Furthermore, total antioxidant concentrations were less in SY03 than SS03 horses (P < 0.05), and were less in SY03 and SY04 than CTRL horses (P < 0.05). These results could be interpreted as an improvement in the preventive antioxidant systems of horses fed Se yeast. Total white blood cell count was not affected by treatment. There was a tendency for horses receiving greater concentrations of Se yeast to have greater lymphocyte counts (P = 0.09), with greater lymphocyte counts in blood of SY03 vs. SS03 horses (P < 0.05). Despite the lack of effect of Se source and dose on markers of inflammatory and liver status, the hematological profile seems to indicate an immunomodulatory action, as shown by mild changes in the white blood cell populations in response to Se yeast inclusion.

The effect of selenium supplementation on vaccination response and immune function in adult horses1

“…Changes in lymphocyte numbers in response to Se supplementation in the horse have been reported (Calamari et al, 2010). However, in this study.…”

Effects of added chelated trace minerals, organic selenium, yeast culture, direct-fed microbials, and Yucca schidigera extract in horses. Part I: Blood nutrient concentration and digestibility1

“…The findings of this study are similar to those of Richardson et al (2006), who reported no clear advantage of dietary organic (in the form of Zn-L-selenomethionine) vs. inorganic (sodium selenite) sources on the Se status of horses. The findings of Calamari et al (2010) also indicated no effect of Se source or dosage level on plasma metabolites related to energy, protein, and mineral metabolism, acute phase A i 16 U 12 JO 6 i i O proteins, and enzyme activities related to hepatocellular, hepatobiliary, or muscle damage. Conversely, Pagan et al (1999) reported greater apparent digestibility as well as Se retention in horses receiving sources of Se yeast vs. sodium selenite.…”

Exploring Fourier transform mid-infra-red spectrometry to predict biochemical parameters in horse’s blood

“…Descriptive statistics are displayed in Table 1. The horses selected for this study were all clinically healthy with the concentrations of the blood parameters within the reference ranges reported for horses without clinical signs of disease (Calamari et al 1990(Calamari et al , 2010Abeni et al 2013). The blood parameters with the lowest variability (CV <10%; Table 1), in ascending order, were Na, Cl, Ca, albumin, total protein, glucose and Mg.…”