Effect of Piglet Weaning Age on mRNA and Protein Expression of Heat Shock Proteins

The study objective was to determine the effects of weaning age on piglet HSPs. Piglets were randomly assigned to four groups (n=6 per group) that were weaned at 14, 21, 28, or 35 days of age. HSP27, HSP70, and HSP90 mRNA levels and proteins were measured in kidney, myocardium, and longissimus dorsi muscle. In the kidney, HSP70 mRNA and protein levels were significantly higher in piglets weaned at 14 and 21 days compared to piglets weaned at 35 days (p < 0.05), and HSP90 expression was significantly lower in piglets weaned at 21 days compared to other groups (p < 0.05). In myocardium, weaning at 21 and 28 days resulted in significantly higher HSP70 mRNA expression compared to weaning at 14 and 35 days (p < 0.05). Myocardial HSP90 mRNA expression in piglets weaned at 28 days was significantly lower compared to piglets weaned at 14 days, and weaning at 14 days resulted in significantly higher myocardial HSP70 expression compared to weaning at 35 days (p < 0.05). In longissimus dorsi muscle, weaning at 21 days resulted in significantly lower expression of HSP70 mRNA compared to weaning at 14 days of age (p < 0.01), and piglets weaned at 21 days had significantly lower expression of HSP90 and HSP27 compared to piglets weaned at 35 days (p < 0.05). These results indicate that expression of HSP genes and protein in piglets was affected by weaning age, and the HSP expression pattern was different among different tissues. Changes in HSP expression may be the reason for differences in growth performance and immune and antioxidant function variations in piglets. (C) 2018 Friends Science Publishers