J. T. Lee

Evaluation of NSPase inclusion in diets manufactured with high- and low-quality corn on male broilers

SUMMARY The objective of the current study was to evaluate the efficacy of non‐starch polysaccharide degrading enzymes (NSPase) inclusion in diets manufactured with high‐ and low‐quality corn on male broilers. Low‐quality corn was achieved with the inclusion of 20% corn screenings (CS), and formulations were made on an isonitrogenous and isocaloric basis. Three energy levels were fed throughout the study with and without CS: high energy (HE), low energy (LE, less 110 kcal/kg), and LE with NSPase (LEN). The inclusion of CS decreased (P < 0.05) starter feed consumption (FC) and thus negatively impacted (P < 0.05) d 14 body weight (BW). Reduction of dietary energy increased (P < 0.05) starter mortality corrected feed conversion ratio (FCR). A significant interaction (P < 0.05) was observed on d 27 relating to BW and FC between diet type and energy level, as benefits associated with NSPase inclusion were more pronounced in diets containing CS. Addition of CS increased grower and cumulative FCR (d 1 to 27) as compared to diets excluding screenings. Reduction of dietary energy increased (P < 0.05) grower and cumulative (d 1 to 27) FCR in the LE fed broilers as compared to the HE broilers. FCR was improved (P < 0.05) in the LEN diet during the grower phase and through 27 d of age compared to the LE diet. During the finisher phase, broilers fed diets containing CS exhibited a lower (P < 0.05) FCR as compared to broilers fed diets without screenings. Reduction in dietary energy increased (P < 0.05) FCR; however, inclusion of NSPase diet reduced (P < 0.05) FCR to a level comparable to the HE. In conclusion, the use of CS did not impact final performance, and the inclusion of NSPase reduced FCR when fed in reduced energy diets.

Evaluation of a thermotolerant xylanase on broiler growth performance and dietary ileal digestible energy value

&NA; Two experiments were conducted to evaluate the impact of a thermotolerant xylanase on male broiler performance and dietary ileal digestible energy (IDE). The first experiment consisted of 3 treatment groups with 12 replications per treatment each containing 35 Cobb 500 males for a total of 1,260 broilers placed in floor pens for a 42 d grow‐out. The experiment treatments included a corn/soy diet with DDGS control formulated at a low energy level, and the control supplemented with one of 2 concentrations of xylanase (20,000 XU/kg [XYL20] and 40,000 XU/kg [XYL40]). No significant differences in body weight were observed with the inclusion of xylanase when compared to the control diet throughout the experiment. At d 28, the inclusion of XYL20 improved (P < 0.05) mortality corrected feed conversion ratio (FCR) compared to the control diet. Feed conversion ratio was also improved (P < 0.01) at d 42 for birds fed XYL20 when compared to the control. At d 42, inclusion of XYL20 and XYL40 significantly (P < 0.05) increased IDE compared to the control. Experiment 2 consisted of 4 treatment groups with 10 replications per treatment each containing 44 Cobb 500 males for a total of 1,760 broilers placed in floor pens for a 41 d grow‐out. The dietary treatments included a positive control (PC) based on a corn/soy diet containing DDGS and phytase, a negative control (NC) diet (PC ‐150 kcal/kg in AME), NC + xylanase at 10,000 XU/kg (XYL10), and NC + xylanase at 20,000 XU/kg (XYL20). A significant increase (P < 0.05) in BW was observed in broilers fed the inclusion of XYL20 in the NC diet increased (P < 0.05) on d 14. A significant increase in cumulative body weight gain was observed on d 27 and d 41 with xylanase (XYL20) inclusion compared to the NC. These data demonstrate that xylanase inclusion increased energy utilization through improvements in IDE, which improved broiler performance.