@article{pope_brake_fahrenholz_2020, title={Parameters monitored during the pelleting process and their relationship to xylanase activity loss}, volume={259}, ISSN={["1873-2216"]}, DOI={10.1016/j.anifeedsci.2019.114344}, abstractNote={Exogenous enzymes have been regularly used in broiler diets to improve the value of raw ingredients by enhancing their digestibility. Broiler feed has also been most commonly pelleted, which has exposed mixer-added exogenous enzymes to pressure and heat. These conditions have often resulted in mixer-added exogenous enzyme denaturation and inactivation. The present experiment was intended to define the relationship between parameters monitored during the pelleting process, such as change in temperature between hot pellets and conditioned mash (ΔT), pellet durability index (PDI), and pellet mill energy consumption (PMEC) and the stability of a mixer-added xylanase throughout the pelleting process. To generate a range in values for ΔT, PDI, and PMEC, diets were pelleted with varying concentrations of fat and degrees of saturation of fat through two pellet mill dies with varying length-to-diameter ratios at a constant temperature of 82 °C. It was determined that as ΔT, PDI, and PMEC increased, xylanase recovery in pellets relative to unconditioned and conditioned mash decreased (P = 0.001). When select parameters monitored during the pelleting process were combined with select controlled factors, a multiple regression model was generated (P = 0.001; R2 = 0.84). These data indicated that practices implemented to improve PDI may negatively affect the stability of heat sensitive mixer-added exogenous enzymes during the pelleting process and that predictive models could be generated to better predict the impact of implementing feed manufacturing practices to improve pellet durability on enzyme thermostability.}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Pope, J. T. and Brake, J. and Fahrenholz, A. C.}, year={2020}, month={Jan} }
 @article{pope_fahrenholz_2020, title={The effect of the level of mixer-added water and mash conditioning temperature on parameters monitored during pelleting and phytase and xylanase thermostability}, volume={269}, ISSN={["1873-2216"]}, DOI={10.1016/j.anifeedsci.2020.114679}, abstractNote={Exogenous enzymes have been used in broiler and swine rations to improve nutrient utilization and reduce feed costs, both of which improved the efficiencies of live production. Feed manufacturers have also utilized practices, such as warm mash conditioning temperatures (CT) and the addition of moisture at the mixer or mash conditioning chamber, to maintain adequate physical feed quality. While the impact of warm conditioning practices on enzyme thermostability had been well described, the impact of mixer-added water (MAW) on enzyme thermostability was scarcely investigated in previous literature. The present experiment intended to investigate the interaction of three mash CT and three levels of MAW on the thermostability of a phytase and xylanase mixer-added enzyme within a swine gestation diet in a 3 × 3 factorial randomized complete block design. The mash CT included 80, 86, and 92 °C and the levels of MAW included 0, 10, and 20 g/kg. Parameters monitored during the pelleting process included pellet durability index (PDI), pellet mill energy consumption (PMEC), and the change in temperature between hot pellets and conditioned mash (Δ T). Conditioning mash at 92 °C resulted in a 22.5 percentage-point reduction in phytase recovery in conditioned mash and a 70.1 percentage-point reduction in phytase recovery in pellets when compared to diets pelleted at 80 °C (P < 0.01). The xylanase, however, was not affected by mash CT. Phytase and xylanase recovery in pellets was not affected by the level of MAW. As PDI and PMEC increased, phytase recovery in pellets relative to unconditioned mash decreased (P < 0.01). As Δ T increased, phytase recovery in pellets relative to unconditioned mash increased (P < 0.01). Xylanase denaturation was poorly described by the parameters monitored during pelleting, likely because it was minimally denatured during pelleting. A robust multiple regression model was generated to predict phytase activity in pellets relative to unconditioned mash (R2 = 0.95; P < 0.01) when the controlled factors and monitored parameters were combined in a predictive model. In conclusion, the primary site of enzyme denaturation in a pilot scale pellet mill was the pellet mill die and MAW did not affect enzyme recovery.}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Pope, J. T. and Fahrenholz, A. C.}, year={2020}, month={Nov} }
 @article{pope_brake_fahrenholz_2018, title={Post-pellet liquid application fat disproportionately coats fines and affects mixed-sex broiler live performance from 16 to 42 d of age}, volume={27}, ISSN={["1537-0437"]}, DOI={10.3382/japr/pfx054}, abstractNote={Abstract The effect of 2 fat application sites (FAS) and 2 levels of fines on feed manufacturing parameters and broiler live performance from 16 to 42 d was studied. The FAS included mixer‐added fat (MAF) and post‐pellet liquid application (PPLA) of fat. While the MAF diets had all fat added to the diet prior to pelleting, the PPLA diets were pelleted with 0.5% MAF, and the remaining 3.5% fat was added subsequent to pellet cooling. The levels of fines included 0 and 30%. A total of 32 pens was placed with 8 males and 8 females (mixed‐sex) in each pen. Broiler chicks were fed a common crumbled starter for approximately 16 d and then transitioned to one of the 4 dietary treatments. The PPLA pellets were more durable than were MAF pellets (P < 0.01), but required more energy to pellet (P < 0.01). When adding liquid fat post pellet to the diets with 30% fines, the fines absorbed more liquid fat and exhibited a greater gross energy when compared to pellets (P < 0.01). Male broilers consuming the PPLA diets were 50, 97, and 120 g heavier than male broilers consuming the MAF diets at 28, 35, and 42 d, respectively (P < 0.01). Female broilers consuming the PPLA diets with 30% fines were 71 and 90 g heavier than female broilers consuming the MAF diets with 30% fines at 28 and 35 d, respectively (P < 0.05). It was concluded that the females may have benefited from consuming high‐energy‐density fines present in the PPLA diets with 30% fines when compared to females consuming MAF diets with 30% fines because the additional fat that coated the fines offset the negative energy associated with prehension of the fines.}, number={1}, journal={JOURNAL OF APPLIED POULTRY RESEARCH}, author={Pope, J. T. and Brake, J. and Fahrenholz, A. C.}, year={2018}, month={Mar}, pages={124–131} }