Effect of Dietary Supplementation of Glutathione on Blood Biochemical Changes and Growth Performances of Holstein Calves (Report‪)‬

INTRODUCTION Glutathione (GSH) is a beneficial protein in every cell of the body which functions as an antioxidant, immune system optimizer, detoxifier, energy restorer, and anti-aging protein. It is an important substance particularly with regards to elimination of waste matter from the body and one of the most important connections to the widely distributed tripeptide thiol GSH. Indeed there is a strong evolutionary link between GSH and eukaryotic aerobic metabolism that is reflected in the function of GSH in protection against oxygen toxicity (Fahey and Sundquist, 1991). GSH is not required in the diet of animals but is synthesized in virtually all animal cells by the sequential actions of two enzymes: y-glutamylcysteine synthetase and GSH synthetase. GSH deficiency can be reduced by supplementary administration to animals. Jain et al. (1991) and Meister (1995) found that when such GSH deficiency occurred in newborn rats or guinea pigs, the animals developed multi-organ failure and died within a few days. This result is directly related to the loss of an essential antioxidant system. The animals exhibited focal necrosis in the liver, proximal tubular damage in the kidneys, and disruption of lamellar bodies in the lung. Newborns with GSH deficiency developed brain damage (Martensson and Meister, 1991) and also cataracts (Calvin et al., 1986). Calves are exposed to viruses, bacteria, and parasites in the environment which are capable of causing respiratory problems and diseases. These are stress factors that can significantly reduce the GSH reservoir. Reduced GSH levels result in lower energy, higher inflammation, cellular damage, and a weakened resistance to various diseases. Thus, the objective of this experiment was to evaluate the effect of supplemental GSH on health, solid feed consumption, nutrient intake, body weight gain (BWG), feed efficiency, blood metabolites and the occurrence of diarrhea in Holstein neonatal calves.