将30头猪（42日龄，初始体重（BW）12.49±1.45 kg）随机分配到三种氧化蛋白水平的日粮处理组中的一组。以喷雾干燥的牛血浆作为蛋白质来源，分别为不加热、45℃加热4 d和100℃加热3 d。饲喂19 d，测定生长性能。收集血浆（0和18d）、空肠、结肠和肝脏组织（19 d），分析氧化应激标志物（如蛋白氧化、脂质氧化、DNA损伤和谷胱甘肽过氧化物酶活性）。
试验数据显示，平均日增重（ADG，P < 0.01）和平均日采食量（ADFI，P < 0.01）与蛋白质氧化水平呈线性正相关，但饲料转化率（GF）无影响。此外，日粮中蛋白质（P = 0.03）和脂肪（P < 0.01）的消化率随蛋白质氧化率的增加而降低。隐窝深度与日粮蛋白氧化水平呈线性正相关（P = 0.02）。与未加热或加热至100℃的血浆喂养的猪只相比，饲喂加热到45℃的血浆蛋白组猪只在肝脏样本中观察到脂质氧化程度有增加的趋势（P = 0.09）。空肠DNA损伤与日粮蛋白氧化水平有线性关系的趋势（P = 0.07）。
Impact of dietary oxidized protein on oxidative status and performance in growing pigs
Rendered products from the meat industry can provide economical quality sources of proteins to the animal and feed industry. Similar to lipids, rendered proteins are susceptible to oxidation, yet the stability of these proteins is unclear. In addition, interest in understanding how oxidative stress can impact efficiency in production animals is increasing. Recent studies show that consumption of oxidized lipids can lead to a change in the oxidative status of the animal as well as decreases in production efficiency. To date, little is known about how consumption of oxidized proteins impacts oxidative status and growth performance. The objectives of this study were to determine if feeding diets high in oxidized protein to growing pigs would: 1) impact growth performance and 2) induce oxidative stress. Thirty pigs (42 d old; initial body weight [BW] 12.49 ± 1.45 kg) were randomly assigned to one of three dietary treatments with increasing levels of oxidized protein. Spray-dried bovine plasma was used as the protein source and was either unheated upon arrival, heated at 45 °C for 4 d, or heated at 100 °C for 3 d. Diets were fed for 19 d and growth performance was measured. Blood plasma (days 0 and 18), jejunum, colon, and liver tissues (day 19) were collected to analyze for markers of oxidative stress (e.g., protein oxidation, lipid oxidation, DNA damage, and glutathione peroxidase activity). Average daily gain (ADG;P < 0.01) and average daily feed intake (ADFI;P < 0.01) had a positive linear relationship to increased protein oxidation, but there was no effect on gain to feed ratio. Furthermore, protein (P = 0.03) and fat (P < 0.01) digestibility were reduced with increased protein oxidation in the diet. Crypt depth showed a positive linear relationship with dietary protein oxidation levels (P = 0.02). A trend was observed in liver samples where pigs fed the plasma heated to 45 °C had increased lipid oxidation compared with pigs fed the plasma either unheated or heated to 100 °C (P = 0.09). DNA damage in the jejunum tended to have a linear relationship with the dietary protein oxidation level (P = 0.07). Even though results suggest dietary oxidized protein did not induce oxidative stress during short-term feeding, differences in performance, gut morphology, and digestibility are likely a result of reduced protein availability.