ABSTRACT

This study was conducted to evaluate the relationship between quantitative traits and biologic markers in two commercial meat type chickens in a humid tropical environment. A total number of 60 each of Marshal and Anak broiler chicken strains were used for the experiment which lasted for 56 days (8 weeks). The experiment was carried out at the Poultry Unit of the Teaching and Research farm of Michael Okpara University of Agriculture, Umudike, where the birds were raised in separate deep litter pens. Each strain was replicated 3 times with 20 birds per replicate. Data collected include body weight and linear body traits (keel length, shank length, thigh length, wing length and neck length) at weekly interval beginning from 3^rd week and haematological parameters or biologic markers including packed cell volume, haemoglobin, red blood cell, white blood cell, total protein and cholesterol. Data were analyzed using independent student’s t-test statistic and Pearson’s product moment correlations were done to establish associations between biologic markers and growth traits and among the growth traits.  Results showed that Marshal strain had significantly(p<0.05) higher performances in growth traits including body weight, wing length and keel length and in haematology parameters including packed cell volume, haemoglobin and white blood cell across the weeks studied Eg  week3-4;A-b and body weight=0.841, WBC and body weight=0.678,WBC and neck length=0.977,TPand neck length=0.643; for week 5-6:Hb and body weight=0.647, TP and body weight=0.884, cholesterol and keel length=0.653; for week 7-8:PCV and body weight =0.773.. Based on the association among the conformation traits, strain differences were noticed in the strong association between body weight and shank length as 0.720 and between body weight and wing length as 0.670 in the Anak broiler strain. Important associations were established between the growth traits and biologic markers which could be used in place of pure genetic markers. Thus, the following associations may be generally recommended for breed selection purposes: PCV with shank length, body weight; Hb with body weight, wing length; WBC with body weight, neck length, RBC with body weight; total protein with neck length, body weight; and cholesterol with wing length, thigh length, keel length, shank length and neck length. In conclusion, the Marshal strain performed higher than the Anak strain in terms of conformation traits and biologic marker characteristics across the ages studied which though reduced with advancement in age, and is thus recommended for farmers who prefer breeds with better conformation traits for economic reasons.