Efficacy of new phytase enzymes for increasing dietary phosphorus utilization by laying hens

Three experiments were conducted to determine the efficacy of new phytase enzymes in laying hen diets. The first study focused on corn-expressed phytase (CEP) enzyme in low-nonphytate phosphorus (NPP) diets and whether CEP was a beneficial source of phytase for optimal production in laying hens. Eight diets were fed to 7 replicates of 14 caged laying hens over 24 weeks to observe production performance of hens in two phases: 31 to 48 weeks of age and 49 to 54 weeks of age. Diet 1 consisted of a negative control corn-soybean meal diet containing 0.12% NPP in phase 1 (0-18 weeks) and 0.11% NPP in phase 2 (19-24 weeks). For each phase, Diet 2 was as Diet 1 with 500 FTU/kg of CEP, Diet 3 was as Diet 1 with 3000 FTU/kg of CEP, and Diet 4 was as Diet 1 with 500 FTU/kg of commercially available phytase. Diet 5 was a diet containing 0.30% NPP. Diet 6 was as Diet 5 with 500 FTU/kg of CEP and Diet 7 was as Diet 5 with 3000 FTU/kg of CEP. Diet 8 was a positive control diet containing 0.45% NPP. Hens fed the negative control diet, Diet 1, had reduced (P<0.05) production performance for many measured parameters compared with hens fed the other diets. Performance of hens fed diets supplemented with CEP was not significantly different (P>0.05) than that of hens fed diets supplemented with the commercial phytase or the 0.45% NPP positive control diet. These results indicated that the CEP was efficacious for increasing the utilization of phosphorus (P) by laying hens fed corn-soybean meal diets. Experiments 2 and 3 evaluated a new phytase enzyme for its efficacy to increase P utilization in younger and older laying hens. Experiment 2 included 3 diets consisting of a corn-soybean meal negative control P-deficient diet, or the negative control diet supplemented with 187.5 or 375 FTU/kg of phytase. Each of the 3 diets were fed to 15 replicates of 1 caged hen over the course of 7 days beginning at 30 weeks and 34 weeks of age. Experiment 3 had 3 diets consisting of a negative control P-deficient corn-soybean meal diet containing 0.11% NPP, Diet 2, which was Diet 1 with 150 FTU/kg phytase, and Diet 3, which was a positive control diet containing 0.45% NPP. Each diet was fed to 6 replicates of 14 caged laying hens from 75 weeks of age to 87 weeks of age. Hens in Experiment 2 exhibited no significant differences for production performance among dietary treatments; however, P retention was increased by 187.5 and 375 FTU/kg of phytase. In Experiment 3, hens fed the negative control diet displayed a rapid reduction in feed consumption, egg production, egg mass, and feed efficiency and this treatment was terminated after 5 weeks. There were no significant differences in egg production performance between hens fed the diet with 150 FTU/kg of phytase and hens fed the positive control 0.45% NPP diet. The results of Experiment 2, based on P retention, and Experiment 3, based on egg production performance, clearly indicated that the new phytase enzyme was efficacious for increasing dietary P utilization by laying hens fed corn-soybean meal diets.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Bornholt, Kersten

Contributors dc:contributor

• Parsons, Carl M
• Emmert, Jason
• Koelkebeck, Ken W

• phytase
• laying hens
• phosphorus

Statement dc:rights

• Copyright 2022 Kersten Bornholt

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/116142

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F116142