Objective: To investigate the effect of the interaction between dietary sesame meal (SSM) level and levels of microbial phytase supplementation on growth performance, carcass traits and some blood plasma constituents of broilers. Methods: A total of 288 one-day-old unsexed
Cobb chicks were randomly allocated in 12 experimental treatments for 42 days. Each treatment had 24 broilers arranged in 3 replicates of 8 broilers each. A 4 × 3 factorial arrangement of 12 dietary treatments was used including four levels of SSM (i.e., 0, 250, 500, 1 000 g/kg) and three levels of microbial phytase (i.e., 0, 300, 600 FTU/kg). At 42 days of age, nine birds per treatment
(three birds per replicate) were randomly selected and fasted for 12 h and killed. Abdominal fat, giblets, and dressing proportion were recorded. Blood samples were collected from five birds of each replicate and used for determination of total protein (TP), albumin, total cholesterol (COL), triglycerides (TG), liver aspartate amino transferase enzyme (AST) and alanine amino transferase
(ALT), calcium (Ca), inorganic P, globulin and albumin to globulin ratio. Results: the experiment showed that SSM level had a significant effect on average body weights of broilers for the studied experimental periods, where negative effects were observed on body weights with increasing SSM level (i.e., 500 and 1 000 g/kg). The same was true for the interaction between SSM and phytase.
SSM level, significantly, affected feed CR during the studied growth periods (P<0.01). The dressing proportion, giblets and abdomen fat were significantly (P<0.01) affected by the SSM, however, none of these variables were affected by phytase. Diets with 1 000 g/kg SSM and 600 FTU/kg showed the highest (P<0.05) giblets percentage. Phytase supplementation significantly (P<0.01) affected the plasma TP, albumen, globulin, albumin: globulin ratio, COL and ALT activity. SSM by phytase interaction significantly affected plasma content of total TP, globulin, albumin: globulin ratio,
COL, TG, ALT activity and Ca. However, it had no effect on plasma albumin (P=0.07), AST activity
(P=0.06) and inorganic P (P=0.19) levels. Conclusions: SSM had positive effects on broilers performance especially at low inclusion level. However, SSM and phytase had variable effects on plasma con-stituents. More research is needed to conclude the appropriate supplementation levels of SSM and phytase.