Effect of dietary supplementation with Rhizopus oryzae or Chrysonilia crassa on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

Abstract. Dietary supplementation of additives has recently been part of strategies to deal with the detrimental effects of heat stress (HS) on the performance and carcass traits in broiler chicks. This study aimed to investigate the effect of dietary supplementation with the fungi Rhizopus oryzae or Chrysonilia crassa on growth, blood profile, intestinal microbial population and carcass traits in broiler chicks subjected to HS. R. oryzae and C. crassa are filamentous fungi isolated from the ileum of indigenous Indonesian chickens which exhibited probiotic and antioxidant properties. Two hundred and forty 21-day-old male broiler chicks were randomly allotted into six groups, including birds reared under normal temperature (28 ± 2 °C) (CONT), birds reared under HS conditions (35 ± 2 °C) (HS-CONT), birds reared under HS and provided with commercial anti-stress formula (HS-VIT), birds reared under HS and provided with R. oryzae (HS-RO), birds reared under HS and provided with C. crassa (HS-CC) and birds reared under HS and provided with rice bran (HS-RB). Body weight gain was highest (P < 0. 01) and lowest (P < 0. 01) in CONT and HS-CONT birds, respectively. The heart was heavier (P < 0. 05) in CONT than in HS-CONT and HS-VIT birds. CONT birds had heavier duodenum (P < 0. 05) and jejunum (P < 0. 01) than other birds. Eosinophils was higher (P < 0. 05) in HS-CC than in other birds. Low-density lipoprotein (LDL) was higher (P < 0. 05) in HS-CONT than in CONT, HS-VIT and HS-CC birds. Total triglyceride was highest (P < 0. 05) and lowest (P < 0. 05) in HS-RB and HS-RO birds, respectively. Alanine aminotransferase (ALT) was higher (P < 0. 05) in HS-CONT than in other HS birds. Total protein was lowest and highest (P < 0. 05) in CONT and HS-CONT birds, respectively. Albumin was higher (P < 0. 05) in HS-CONT and HS-VIT than in HS-RO birds. Globulin was lower (P < 0. 05) in CONT than in HS-CONT, HS-VIT and HS-RB birds. Uric acid was lower (P < 0. 05) in CONT than in HS-CONT and HS-VIT birds. The 2,2′-azino-bis(3-ethyl-benzthiazolin-6-sulfonic acid) (ABTS) percentage inhibition values of the serum were higher (P < 0. 01) in CONT, HS-CONT and HS-VIT than those in HS-RO, HS-CC and HS-RB birds. In conclusion, dietary supplementation of C. crassa decreased serum LDL concentration and ALT activity and improved antioxidant status of broiler subjected to HS. Supplementation with C. crassa seemed beneficial in improving physiological conditions of HS birds.