The ratios between minerals showed better correlations with STH concentrations than the minerals individually.

Ghorbani, A.1; Darmani Kuhi, H.2 and Mohit, A.3

1- PhD Student of Animal Nutrition, Faculty of Agricultural Science, University of Guilan, Rasht, Iran
2- Associated Professor, Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
3- Assistant Professor, Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
Corresponding Author: E-mail: ghorbanee@gmail.com
Iranian Veterinary Journal

Abstract

Despite the critical importance of minerals as a fractional component of hormones, enzymes, tissues and body fluids, they are not produced in the animal body and must be fed by the diets. OBJECTIVES: This study aimed at determining the basic data of serum mineral (SM) and thyroid hormone (STH) concentrations and their relationships in different gender and age groups of Caspian miniature horses fed diets with different mineral contents. This research was conducted on twelve horses using a balanced change over design with four treatments (9 replicates per treatment) in 3 periods and 4 blocks (two genders and two age groups <3 and ≥3 years). Each period extended for 56 days with 7 days interval between the periods. Two different levels (0 and 4.86 % of diet) of minerals were added to one of two different levels of daily dry matter intakes (50 and 100 % of requirements) to make the dietary treatments. The SM and STH contents were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) and Elisa methods, respectively, using blood samples collected from all horses at the end of each period. The mean values of T3, T4, FT3, TSH, and T3/T4 ratios were higher in females than males. The STH was not affected by the dietary treatments and age. The serum Cu content was affected by the dietary treatments. Significant Pearson correlations were observed between T3 with Ca/K (r=0.377), T4 with Ca/K (r=0.331). Due to the body’s homeostatic control mechanisms in healthy animal, the SM and STH concentrations were not affected by the dietary treatments during the experimental period of this study. The ratios between minerals showed better correlations with STH concentrations than the minerals individually.

Key words: the Caspian miniature horse, mineral elements, thyroid hormone, Elisa, ICP-OES