Haematology and hormonal assay of heat-stressed broiler chickens managed by feather clipping and ascorbic acid supplementation

High ambient temperature (HAT) induces stress in birds and affects their wellbeing. This study investigated the haematology and serum levels of corticosterone, triiodothyronine and thyroxine of heat-stressed broilers managed by feather clipping (FC) and ascorbic acid (AA) supplementation. Methods: One hundred Anak broiler chicks were distributed into five treatments of 20 chicks each in 2 replicates and were all fed basal diets. The positive control (PC) birds were intact (not feather clipped) and managed under controlled (28 – 30℃) environment. Other groups were managed in open pen under HAT (43.0 ± 2.0℃). The negative control (NC) birds were intact. The treatment 1(T1) birds were feather-clipped, the treatment 2 (T2) groups were intact, together with 200 mg AA/kg feed supplemented while the treatment 3 (T3) birds were feather-clipped and fed with 200mg AA supplemented feed. Data were analysed using ANOVA. Results: The results showed that feather clipping and AA supplementation did not affect blood parameters of the birds except white blood cell count and heterophil-lymphocyte ratio. The levels of the three hormones differedsignificantly (P <0.05) in the PC group compared to HAT-exposed groups. Corticosterone levels decreased in T1 (8.20 ng/mL) and T3 (7.99 ng/mL) significantly against 9.70 ng/mL in NC, the lowest value of 7.88 ng/mL was recorded in PC. Triiodothyronine (4.04 ng/mL) and thyroxine (11.29 ng/mL) levels were highest in PC, lowest triiodothyronine (2.78 ng/mL) and thyroxine (7.97 ng/mL) concentrations were recorded in NC and T1 groups respectively. Significance: Therefore, feather clipping and/or AA supplementation ameliorated adverse effect of extreme heat in the broiler chickens.