Biomechanical Properties of the Gastrocnemius Tendon in Broilers Experimentally Infected with Avian Reovirus

Abstract

The main objective of this study was to determine the relationship of infection with S1133 avian reovirus to tendon integrity in male broilers. Reovirus-infected broilers had histopathological lesions consisting initially of a light infiltrate of heterophils and a more diffuse infiltrate of lymphocytes in the peritendenal tissues and tendon sheath. Subsequently, the lymphocytic infiltrate extended to the epitenon and tendon proper with fibrosis at 10, 14, and 18 weeks post-infection (PI). Ruptured tendons were present at necropsy in 12 of 26 fourteen-week-old infected birds and in 7 of 26 eighteen-week-old infected birds. At six weeks PI, the gastrocnemius tendon of infected birds had significantly (P = 0.05) lower bioyield and ultimate tensile strength than the controls. At 10 and 18 weeks of age, the gastrocnemius tendons of infected birds that had gross tendon lesions had significantly (P = 0.05) lower bioyield and ultimate tensile strength than both the controls and infected birds without gross tendon lesions. The gastrocnemius tendons of infected broilers tended to have a greater resistance to stretch than the controls and were significantly (P = 0.05) more resistant to stretch at 18 weeks.