Roghayeh Jabbari Ori - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz ۵۱۶۶۶-۱۴۸۸۸, Iran.
Jalil Shoja - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz ۵۱۶۶۶-۱۴۸۸۸, Iran.
Ali Esmailizadeh - Department of Animal Science, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman ۷۶۱۶۹-۱۳۳, Iran.
Seyed Abbas Rafat - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz ۵۱۶۶۶-۱۴۸۸۸, Iran.

Ascites syndrome (AS), caused by an imbalance between high oxygen demand and its supply by cardiopulmonary system in broiler chickens, is a major problem in the broiler industry worldwide. An experiment was designed to investigate the differences in biochemical parameters between the ascitic and healthy chickens in a pure broiler sire line under cold conditions. A total of 817 one-day-old mixed-sex chickens from 71 half-sib families were grown and AS was induced on day 21 using a cold temperature model. On the 32nd day of the trial, blood samples from five birds per sire family were collected and blood parameters (hematocrit percentage and serum metabolites including, glucose, total protein, albumin, triglycerides, cholesterol, high-density lipoprotein cholesterol (HDL), calcium, magnesium, phosphorus, alanine aminotransferase, aspartate aminotransferase, malonedialdehyde and total antioxidant status) were measured. The results showed that the male birds were more sensitive to AS than the female birds. Hematocrit percentage of the ascitic chickens was higher than the healthy chickens (P

Cold stress, broiler line, HDL, hematocrit, pulmonary hypertension syndrome