Changes in ghrelin, microminerals, antioxidants and vitamins A, E and C levels during different physiological status in high yielding Saanen goats subjected to heat stress.

Abstract

The aim of this study was to evaluate the changes of ghrelin, microminerals, antioxidants, and vitamins A, E and C levels during different metabolic periods in high yielding Saanen goats subjected to heat stress. Twenty clinically and paraclinically healthy, high yielding and multiparous goats with an average age of 3±0.5 years and pregnant with a single fetus were included in this study. Sampling was performed at three different physiologic periods: non-pregnancy non-lactation (P1), four-month gestation (P2), and first month of lactation (P3). In this study, the ambient temperature ranged from 19 to 42°C and relative humidity ranged from 14 to 19% during the hot months. Serum concentrations of ghrelin, glucose (Glu), superoxide dismutase (SOD), glutathione peroxidase (GPx), vitamins (A, E and C) and microminerals (selenium, manganese, cobalt, iron, copper and zinc) were measured. Mean raw milk yield of the goats per day at the first month of lactation was 2.34±0.2kg. Concentration of ghrelin at P1 was significantly lower than P2 and P3 (P<0.05). Glucose levels were significantly lower at P3 compared with P1 and P2 (P<0.05). There were no significant correlations between ghrelin and Glu at different periods. Concentrations of selenium and manganese were significantly higher at P3 compared with P2 and were significantly higher at P2 compared with P1. Values of copper at P2 were significantly higher than P1 and P3 (P<0.05). Zinc levels were significantly higher at P1 compared with P2 and P3 (P<0.05). Values of antioxidants and vitamins were significantly lower at P3 compared with P2. It is concluded that high yielding Saanen goats may suffer from hormonal and metabolic disturbances, oxidative stress and micromineral deficiencies during late gestation and the first month of lactation especially when they are subjected to heat stress.