Institution: Mississippi State University
Principal Investigator: Pratima Adhikari, Ph. D.
Department of Poultry Science
Mississippi State University
325 Wise Center Drive
MS State, MS 39762
While the benefits of phytases in poultry nutrition are widely recognized, the use of proteases in commercial formulations still require greater acceptance. Proteases have been used as a part of multi-enzymes until recently, when they have been evaluated alone. There is a concern about egg size getting too big if protein and amino acids (AAs) in the diet are too high, but there is also a concern in the reduction of egg size and egg production if AAs are reduced by providing
matrix value to the protease during feed formulation. There is a lack of information for industry nutritionist to use protease in order to improve production as well as to save feed cost. The objective of this project was to determine the role of protease in egg production, egg quality and reduced feed cost by improving AA utilization in post-peak and late-lay of egg production.
A long-term study was conducted to investigate the feeding effect of protease along with various levels of crude protein (CP) and AAs in layer feed. The study was divided into two phases, 30-50 weeks of age and 50-70 weeks of age. The effect of supplementing exogenous protease enzyme on egg size, egg solids, performance and digestibility of nutrients in different phases of laying hens were determined. Hens were fed a corn-soybean meal-based layer feed in all mash form. The study was a complete randomized design with 2 x 4 factorial arrangement of protease (yes and no) and AA levels (100, 95, 90 and 85% of breeder recommendation).
The effect of the protease was beneficial in understanding the AA digestibility in both the early and late-lay phases. In the 30-50 weeks study, the interaction of AA levels and protease was observed for the hen day egg production. Researchers did not observe any interaction of protease and CP/AA on economic return. The lowest level of AA diets hindered laying performance and economic return. In the 50-70 weeks study, there were significant AA levels and protease interactions for egg production, percent yolk, and coefficient of apparent ileal digestibility for CP and several other AAs. However, no interactions or effects were found for feed intake, specific gravity, shell thickness, percent albumen, total solids and other components. This study did not show an effect of protease in reducing the egg size.
