De Jong J A, Woodworth J C, DeRouchey J M, Goodband R D, Tokach M D, Dritz S S, Stark C R, Jones C K
Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506.
Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506.
Transl Anim Sci. 2017 Sep 1;1(3):255-260. doi: 10.2527/tas2017.0030. eCollection 2017 Sep.
Phytase is a feed-grade enzyme frequently added to swine diets to help improve the digestibility of phytate phosphorus. However, like any enzyme, it may be subject to heat damage when exposed to thermal processing. Therefore the objective of this experiment was to determine the stability of 4 commercial phytase products exposed to increasing thermal conditioning temperatures in the pelleting process. The 4 commercial products used were: Quantum Blue G (AB Vista, Plantation, FL); Ronozyme Hi Phos GT (DSM Nutritional Products, Parsippany, NJ); Axtra Phy TPT (Dupont, Wilmington, DE), and Microtech 5000 Plus (Guangdong Vtr Bio-Tech Co., Ltd., Guangdong, China). The phytase products were mixed as part of a corn-soybean meal-based swine diet at a concentration recommended by the manufacturer to provide a 0.12% aP release. Diets were exposed to each of 4 thermal conditioning temperatures (65, 75, 85, and 95°C) and the entire process repeated on 4 consecutive days to create 4 replicates. Samples were taken while feed exited the conditioner and before entering the pellet die. Samples were cooled to room temperature before being stored in plastic bags until analysis. Phytase stability was measured as the residual phytase activity (% of initial) at each conditioning temperature. There were no product × temperature interactions observed for conditioning temperature, conditioner throughput, or residual phytase activity. As target temperature increased, conditioner throughput decreased (linear; < 0.001) and phytase activity decreased (linear; < 0.001) for each product. Residual phytase activity decreased as conditioning temperature increased from 65 to 95°C at a rate of -1.9% for every 1°C increase in conditioning temperature. There was a significant phytase product ( < 0.001) main effect which was mainly driven by Microtech 5000 Plus having decreased ( < 0.05) phytase activity when compared to all other products at 65, 75, and 85°C. However at 95°C Axtra Phy TPT had greater ( < 0.05) residual phytase activity compared with Microtech 5000 Plus, with Quantum Blue G and Ronozyme Hi Phos intermediate. Increasing target conditioning temperatures decreased phytase stability regardless of product. In addition, Microtech 5000 Plus had decreased residual phytase activity (% of initial) when compared to all other products at 65, 75, and 85°C.
植酸酶是一种常用于猪饲料中的酶，可提高植酸磷的消化率。然而，与任何酶一样，在热加工过程中可能会受到热损伤。因此，本实验的目的是确定4种商业植酸酶产品在制粒过程中，随着调质温度升高时的稳定性。所使用的4种商业产品分别是：Quantum Blue G（AB Vista公司，佛罗里达州种植园）；Ronozyme Hi Phos GT（帝斯曼营养产品公司，新泽西州帕西帕尼）；Axtra Phy TPT（杜邦公司，特拉华州威尔明顿）和Microtech 5000 Plus（广东溢多利生物科技股份有限公司，中国广东）。将植酸酶产品按照制造商推荐的浓度添加到以玉米-豆粕为基础的猪饲料中，以提供0.12%的有效磷释放量。饲料分别在4个调质温度（65、75、85和95°C）下进行处理，并在连续4天重复整个过程以形成4个重复。在饲料离开调质器并进入制粒模头之前采集样本。样本冷却至室温后，装入塑料袋中保存直至分析。植酸酶稳定性以每个调质温度下的残余植酸酶活性（初始活性的百分比）来衡量。在调质温度、调质器产量或残余植酸酶活性方面，未观察到产品×温度的交互作用。随着目标温度升高，每个产品的调质器产量降低（线性关系；P<0.001），植酸酶活性降低（线性关系；P<0.001）。当调质温度从65°C升高到95°C时，残余植酸酶活性以每升高1°C降低1.9%的速率下降。存在显著的植酸酶产品主效应（P<0.001），这主要是由于在65、75和85°C时，与所有其他产品相比，Microtech 5000 Plus的植酸酶活性降低（P<0.05）。然而，在95°C时，Axtra Phy TPT的残余植酸酶活性高于Microtech 5000 Plus（P<0.05），Quantum Blue G和Ronozyme Hi Phos GT介于两者之间。无论产品如何，提高目标调质温度都会降低植酸酶的稳定性。此外，在65、75和85°C时，与所有其他产品相比，Microtech 5000 Plus的残余植酸酶活性（初始活性的百分比）降低。
