Abstract
Two experiments were conducted to determine the effects of protease and phytase (PP) and a Bacillus sp. direct-fed microbial (DFM) on dietary energy and nutrient utilization in broiler chickens. In the first experiment, Ross 308 broiler chicks were fed diets supplemented with PP and DFM in a 2×2 factorial arrangement. The 4 diets (control (CON), CON + PP, CON + DFM, and CON + PP + DFM) were fed from 15–21 days of age. In Experiment 1, significant interaction (P≤0.01) between PP and DFM on the apparent ileal digestibility coefficient for starch, crude protein, and amino acid indicated that both additives increased the digestibility. Both additives increased the nitrogen retention coefficient with a significant interaction (P≤0.01). Although no interaction was observed, significant main effects (P≤0.01) for nitrogen-corrected apparent ME (AMEn) for PP or DFM indicated an additive response. In a follow-up experiment, Ross 308 broiler chicks were fed the same experimental diets from 1–21 days of age. Activities of ileal brush border maltase, sucrase, and L-alanine aminopeptidase were increased (P≤0.01) by PP addition, while a trend (P = 0.07) for increased sucrase activity was observed in chickens fed DFM, in Experiment 2. The proportion of cecal butyrate was increased (P≤0.01) by DFM addition. Increased nutrient utilization and nitrogen retention appear to involve separate but complementary mechanisms for PP and DFM, however AMEn responses appear to have separate and additive mechanisms.
Highlights
Supplementation of broiler diets with exogenous enzymes results in increased dietary energy and protein utilization through increased substrate availability [1]
Supplementation of either protease and phytase combination (PP) or direct-fed microbial (DFM) increased the apparent ileal digestibility coefficient (AIDC) of crude protein (CP), but the magnitude was higher with PP
The AIDC for the combination did not differ significantly from either of the additives when fed alone. Both PP and or DFM increased the AIDC significantly compared to the CON diet for all amino acids (AA)
Summary
Supplementation of broiler diets with exogenous enzymes results in increased dietary energy and protein utilization through increased substrate availability [1]. Inclusion of protease alone in broiler diets has to date produced mixed responses [3,4], consistently increased performance due to phytase addition has been reported [5]. Ghazi et al [4] observed increased nitrogen (N) retention in broiler chickens fed protease treated SBM. Protease supplementation has been employed to lower dietary protein level without a reduction in broiler performance [6]. Ravindran et al [8] reported consistently increased N retention in broiler chickens fed supplemental phytase, independent of dietary phytic acid and non-phytate phosphorus levels. The effects of exogenous protease and phytase combination (PP) in broiler diets on dietary nutrient utilization needs to be assessed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
