Effect of Breed, Heterosis and Sex on Body Weight, and Glutathione Peroxidase Activities in Red Blood Cell Haemolysate and Blood Plasma at the Age of Sexual Maturity in Chickens

Abstract

The purpose of the present study was to collect information about the possible genetic background of glutathione peroxidase (GSHPx) activity in four pure breeds and their crosses of chickens, and its correlation with body weight (BW) and studying the effect of cross-breeding and sex on GSHPx activity. Blood samples were collected from six breeds of chickens, New Hampshire (NH), Naked Neck Plymouth (NNP) and their cross (NH×NNP), White Plymouth Rock (WPR), Naked Neck New Hampshire (NNNH) and their cross (WPR×NNNH) at the age of sexual maturity. GSHPx activity measured in blood plasma (BP) and red blood cell haemolysate (RBC). Results showed that there were significant differences in BW and GSHPx activities in RBC and BP among genetic groups and their crosses. NNP had the highest average BW (1.97kg) and NH had the lowest (1.11kg). WPR had the highest RBC GSHPx activity (6.24U/g protein) and NH×NNP cross had the lowest (3.98U/g protein). WPR×NNNH had the highest BP GSHPx activity (7.23U/g protein) and NNNH had the lowest (6.22U/g protein). Crosses had intermediate values for BW compared to their parents. The two crosses had lower RBC GSHPx activity than their parent breeds. NH×NNP had lower BP GSHPx activity than their parent breeds while WPR×NNNH had higher values. Sex had significant effect on BW and GSHPx activity in RBC and BP, males had higher values than females for BW and BP GSHPx activity while the opposite was found in RBC GSHPx activity. Heterosis as a percentage of the midparent values of the GSHPx activities in RBC and BP also average BW has high values and affected by sex. Significant negative correlation was found between BW and RBC GSHPx activity (-0.27; P<0.01) while, positive correlation was found between BW and BP GSHPx activity.