Effect of β-carotene as Antioxidant on Immune Response and Blood Biochemical Changes in Relation to Growth Performance of Heat-Stressed Calves Effect of β-carotene as Antioxidant on Immune Response and Blood Biochemical Changes in Relation to Growth Performance of Heat-Stressed Calves

Abstract

Twenty-four male crossbred calves of 6 –7 months old and 144–150 kg body weight were used to investigate the effect of β-carotene on immunoglobulins (Igs) and some blood constituents, and its relation to growth performance in heat-stressed calves. The animals were maintained under hot summer environmental conditions and randomly divided into two equal groups (12 calves each). The first (control) was offered the basal diet, whereas the second group (treatment) was fed the basal diet plus 50,000 IU β-carotene/calf/day, for 1 month as an experimental period. Total and daily body weight gains were calculated for each calf. Blood samples were collected at the end of the experiment to determine some blood constituents and immunological indices. β-carotene addition to calves’ diet reduced respiration rate, rectal temperature (RT), malondialdehyde, lipid fractions, and a decline in aspartate transaminase and alanine aminotransferase activities. β-carotene significantly increased glutathione reductase, catalase enzyme activities, total antioxidant capacity, and concentrations of total protein, albumin, globulin, calcium, and phosphorus, also improved immunological indices, that is, β-globulin, γ-globulin, and IgG. Moreover, β-carotene enhanced T3 and T4 levels and improved feed efficiency and daily gain. In conclusion, supplementation of growing calves with β-carotene under Egyptian hot summer conditions reduced heat stress effect by RT decrement and modifying most blood constituents and thyroid function, antioxidant, and immunological indices which lead to an improvement in growing calves.