Differential effects of two indigenous broilers exposed to cold stress and characters of follicle density and diameter

Abstract

Indigenous chickens from various part of China, due to different feather characters, always performed differently when countered with cold stress. In this study, the effects of long term hypothermia on serum hormones (triiodothyronine, thyroxine and insulin) and activity of plasma enzymes (Alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, creatine kinase and lactic dehydrogenase) were studied in two indigenous broiler breeds, Huainan partridge (H) and Wenchang (W) chickens. Chickens in 20°C±2°C were compared with those subjected to moderate (15°C±2°C) and severe low temperature (10°C±2°C) for one week. Long-term hypothermia elevated plasma insulin and reduced T4 in W, decelerated insulin and increased T4 in H, while T3 did not change in the two breeds. Plasma enzymes AST, LDH and CK decreased in the two breeds and ALT only decreased in W exposed to cold stress. A significantly decreased body weight gain of H and no variations in W at low temperature were observed. However, a trend of decreased weight gain in W was observed when bred under low temperature condition. Follicle density and diameter were compared in the two breeds with back density in H significantly higher than W and diameter from back of H significantly smaller than W, while much larger than the latter at latero-abdominal part. We investigated the pattern of serum biological change, follicle diameter and density under cold stress condition in two indigenous broiler breeds from different areas of China to provide informative guidance for broiler production and indications in breeding of cold resistant breed.