Wolber Frances M, McGrath Michelle, Jackson Felicity, Wylie Kim, Broomfield Anne
School of Food and Nutrition, Massey University, Palmerston North 4442, New Zealand.
Riddet Innovation, Massey University, Palmerston North 4442, New Zealand.
Nutrients. 2016 Feb 19;8(2):104. doi: 10.3390/nu8020104.
Poultry feathers, consisting largely of keratin, are a low-value product of the poultry industry. The safety and digestibility of a dietary protein produced from keratin (KER) was compared to a cysteine-supplemented casein-based diet in a growing rat model for four weeks. KER proved to be an effective substitute for casein at 50% of the total dietary protein, with no changes in the rats' food intake, weight gain, organ weight, bone mineral density, white blood cell counts, liver glutathione, or blood glutathione. Inclusion of KER in the diet reduced total protein digestibility from 94% to 86% but significantly increased total dietary cysteine uptake and subsequent liver taurine levels. The KER diet also significantly increased caecum weight and significantly decreased fat digestibility, resulting in a lower proportion of body fat, and induced a significant increase in blood haemoglobin. KER is therefore a safe and suitable protein substitute for casein, and the cysteic acid in keratin is metabolised to maintain normal liver and blood glutathione levels.
家禽羽毛主要由角蛋白组成，是家禽业的低价值产品。在生长大鼠模型中，将由角蛋白（KER）制成的膳食蛋白与添加半胱氨酸的酪蛋白基饮食的安全性和消化率进行了四周的比较。结果证明，KER在总膳食蛋白的50%时是酪蛋白的有效替代品，大鼠的食物摄入量、体重增加、器官重量、骨矿物质密度、白细胞计数、肝脏谷胱甘肽或血液谷胱甘肽均无变化。饮食中添加KER使总蛋白消化率从94%降至86%，但显著增加了膳食总半胱氨酸摄取量及随后的肝脏牛磺酸水平。KER饮食还显著增加了盲肠重量，显著降低了脂肪消化率，导致体脂比例降低，并使血液血红蛋白显著增加。因此，KER是酪蛋白的一种安全且合适的蛋白质替代品，角蛋白中的半胱氨酸可代谢以维持肝脏和血液中正常的谷胱甘肽水平。
