Ascorbic acid decreases heat shock protein 70 and plasma corticosterone response in broilers (Gallus gallus domesticus) subjected to cyclic heat stress

摘要

It is known that ascorbic acid (AA) supplementation can ameliorate the chicken's responses to heat stress.The influence of AA on heart heat shock protien 70 (hsp 70) and plasma corticosterone (CS) was evaluated in young male broiler chickens fed either no AA (N-AA) or 500 mg AA/kg (AA) and exposed to cyclic high temperatures (21 to 30 to 21 deg C) over a 2.5 h period on three consecutive days.Dietary AA supplementation elevated plasma AA and maintained it at high levels after heating,but in N-AA birds,only heat elevated plasma AA.In N-AA fed chickens,plasma CS was elevated and was further increased by heat stress as comapred with AA-fed birds.Heart hsp 70 expression was greater in N-AA-fed thickens compared to AA-fed chickens,and heat stress furhter elevated hsp 70 in both N-AA-and AA-fed birds.The hsp 70 increase after heat was two-fold greater in N-AA-vs.AA-fed birds.Plasma CS and heat hsp 70 were positively correlated,plasma AA and heart hsp 70 were negatively correalted,and plasma CS and AA were negatively correlated.it was concluded that chickens experience a less severe stress response after exposure to high temperatures when they are provided dietary AA.