Effect of Alternative Housing Systems on Blood Profile of Egg-type Chickens in Humid Tropics

Aims: General well being of animals is of paramount interest in some developed countries and of global importance hence the shift to alternative housing systems for egg-type chickens as replacement for conventional battery cage system. However, there is paucity of information on the effect of this shift on physiological status of the hens and how it affects their health via the blood profile. Therefore, investigation was carried out on two strains of hen kept in three different housing systems in humid tropics to evaluate changes in their blood parameters.
Study Design: A randomized complete block experimental design was used in this investigation.
Place and Duration of Study: Poultry unit of the Teaching and Research Farm, Bowen University, Iwo, Nigeria between June 2007 and April 2008.
Methodology: One hundred and eight, 17-weeks old Super Black (SBL) hens and one hundred and eight, 17-weeks old Super Brown (SBR) hens were randomly allotted to three different intensive systems namely; Partitioned Conventional Cage (PCC), Extended Conventional Cage (ECC) and Deep Litter System (DLS) in a randomized complete block design with 36 hens per housing system each with three replicates. The experiment lasted 37 weeks during which blood samples were collected at 18th week of age and every two weeks thereafter for analyses. Parameters measured were packed cell volume (PCV), hemoglobin concentration (Hb), Red blood cell counts (RBC), White blood cell counts (WBC) and serum metabolites such as Total Protein (TP), Albumin (Alb),Globulin (Glb), cholesterol, uric acid, serum cortisol and some serum enzymes such as Aspartate Trans aminase (AST), Alkaline Phosphatase (ALP) and Acid Phosphatase (ACP), while blood indices such as Mean corpuscular hemoglobin (MCH),Mean cell volume (MCV) and Mean corpuscular hemoglobin concentration (MCHC) were calculated.
Results: The hematological values of the hens were not significantly (P>0.05) affected by the housing system and strain, while among the serum metabolites, serum cortisol was significantly (P<0.05) affected by the housing system only. Hens housed on PCC had higher values of serum cortisol (20.05 ng/ml for SBL and 20.55 ng/ml for SBR) indicating stress with conventionally caged birds, followed by hens on ECC (18.15 ng/ml for SBL and 18.38 ng/ml for SBL) while hens on DLS had the lowest value (16.50 ng/ml for SBL and 16.00 ng/ml for SBR).
Conclusion: Alternative housing systems can also be adopted for egg-type chickens in the humid tropics from welfare point of view with the results of this work indicate stress among caged hens.