ABSTRACT

This study was conducted to evaluate the effect of age and strain on hematology and biochemical parameters of three broiler strains. - Ross, Arbor Acre and Marshall. A total number of 90 each of the three strains were used for the experiment which lasted for 56 days (8 weeks). The experiment was earned 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. The experimental layout was a 3 x 3 factorial arranged in a Completely Randomized Design (CRD) with three broiler strains (Arbor Acre, Marshall and Ross) and three age groups (4. 6 and 8 weeks) of each strain, which gives rise to 9 treatment combinations. Each treatment combination (Strain x Age) was replicated three times, consisting of 30 birds per replicate. Data collected include hematology parameters: hemoglobin (Hb), Packed Cell Volume (PCV), White Blood Cell (WBC), Red Blood Cell (RBC), Mean Cell Volume (MCV), Mean Cellular Hemoglobin (MCH), Mean Cellular Hemoglobin Concentration (MCHC) and biochemical parameters including glucose and total serum protein. Data were analyzed using Univariate analysis model statistic procedure of SPSS version 20. Result obtained shows that significant main effects (P<0.05) of strain were observed in PCV, RBC and total serum protein of the three broiler strains. The Arbor Acre and Marshal strains similarly recorded higher (P<0.05) values for PCV (31.12% and 31.41%) and RBC (4.57g/dl and 5.02 g/dl) respectively compared to the Ross strain. The Marshal strain in addition recorded the most significant (P<0.05) total scrum protein (4.09 g/dl). No significant effect of strain was observed in Hb, WBC, MCV, MCI1 and MCHC. Based on main effects of age, PCV, WBC and MCV increased (P<0.05), whereas, the MCH, MCHC and glucose decreased (P<0.05) in Ross strain as age increased from week 4 through 8. In the Arbor Acre strain, as age increased, the Hb, PCV, WBC and RBC increased (P<0.05), ' while, glucose decreased (P<0.05) and the MCV fluctuated. In the Marshall strain, the Hb, PCV and WBC increased (P<0.05), whereas, the RBC and glucose fluctuated (P<0.05). as age increased. PCV and WBC similarly increased in the three strains while total serum protein was similarly not affected by age in the three strains which suggests genetic similarity. The three strains showed marked differences in their MCV trend based on the effect of age. Significant interaction effect (P<0.05) were observed in PCV, WBC, MCV, MCH, MCHC and glucose of the Ross, Arbor Acre and Marshall strain in week 4; whereas, in week 6, significant differences (P<0.05) were observed in similar parameters at week 4 except MCHC. In week 8, significant interaction effect (P<0.05) were observed in Hb, PCV, WBC, MCV and glucose. 'The interaction effect showed that the Ross strain had a decreased blood status over time while the Marshall strain and Arbor Acre improved in their blood status over time. Among other parameters, the RBC and total protein were consistently not affected by interaction effect throughout the weeks of study among the three strains. The RBC however, revealed significant differences due to the main effects of age and main effects of strain, whereas, the total protein was affected only by the main effects of strain. The total serum protein is recommended as a haematological index for distinguishing the Ross, Arbor Acre and Marshall Strains. The variation in the MCV of the three strains with respect to age effect suggests different ancestral origin and could be used as a marker for improvement. Based on effect of strain, the Marshall strain had a superior blood profile in  terms of PCV, RBC and total protein compared to the other two and is thus recommended. Abor Acre strain is most- recommended for selection purposes for its relatively high Glucose and protein.