ABSTRACT The chemical characteristics of rapeseed meal (RSM) produced from two cultivars of UK-grown rapeseed, by both supercritical carbon dioxide extraction (ScCO2) and cold-pressed hexane extraction (CpHe) were examined. Their nutritional value, with and without protease, was then assessed in a broiler digestibility trial. Basal feed was substituted with one of four RSM batches (200 g/kg) following adjustments for dry matter (DM) and ether extract (EE) content. Half of each diet was supplemented with a mono-component protease derived from Bacillus subtilis (Axtra®PRO, Danisco Animal Nutrition, Malborough, UK) giving a total of eight test diets. Two control diets, with and without protease were also fed. At 13 d age male Ross 308 broilers were randomly allocated to seven replicate pens (five birds per pen) and assigned to one of 10 diets. Total excreta were collected from 17 to 21 d age and feed intake was recorded. Pre-caecal protein digestibility (pcPd) was determined using TiO2 as an indigestible marker. Colourimetrically CpHe RSM was substantially darker than ScCO2 counterparts. The influence of oil recovery method (ORM) was also evident in DM, EE, ash free neutral detergent fibre (aNDFom), neutral detergent insoluble crude protein (NDICP) and glucosinolate content (GLS). The content of DM, EE and GLS was higher in ScCO2 RSM whereas aNDFom and NDICP levels were greater in CpHe RSM. Protein solubility in KOH was greater in ScCO2 RSM whilst levels of NDICP were lower. Collectively these results suggest that less heat damage was incurred to the RSM during ScCO2 extraction. There was no significant main effect of cultivar nor were any significant interactions observed between treatment factors. Rapeseed meal ScCO2 produced greater metabolisable energy, pcPd, nitrogen retention and energy metabolisability (p < 0.05). Protease supplementation increased pcPd (p < 0.05) irrespective of ORM and cultivar. The key implications of these findings are that by adopting oil recovery methods that minimise the exposure of RSM to thermal treatments and by adding a compatible protease there is scope to increase the nutritional value of RSM for broilers and increase its utilisation in modern poultry production.

中文翻译：

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超临界二氧化碳萃取和冷压正己烷萃取对肉鸡菜籽粕化学成分和饲用价值的影响

摘要研究了通过超临界二氧化碳萃取 (ScCO2) 和冷压己烷萃取 (CpHe) 两种英国种植油菜籽品种生产的菜籽粕 (RSM) 的化学特性。然后在肉鸡消化率试验中评估它们的营养价值，无论是否含有蛋白酶。在对干物质 (DM) 和乙醚提取物 (EE) 含量进行调整后，用四批 RSM 之一 (200 g/kg) 代替基础饲料。每种饮食的一半补充有源自枯草芽孢杆菌（Axtra®PRO，Danisco Animal Nutrition，Malborough，UK）的单组分蛋白酶，总共提供八种测试饮食。还饲喂含和不含蛋白酶的两种对照饮食。在 13 日龄雄性 Ross 308 只肉鸡随机分配到七个重复围栏（每围栏 5 只鸡）并分配到 10 种饮食中的一种。收集 17 至 21 日龄的总排泄物并记录采食量。盲肠前蛋白质消化率 (pcPd) 使用 TiO2 作为难消化标志物进行测定。比色法 CpHe RSM 比 ScCO2 对应物更暗。采油方法 (ORM) 对 DM、EE、无灰中性洗涤纤维 (aNDFom)、中性洗涤不溶性粗蛋白 (NDICP) 和硫代葡萄糖苷含量 (GLS) 的影响也很明显。ScCO2 RSM 中DM、EE 和GLS 的含量较高，而CpHe RSM 中aNDFom 和NDICP 的含量较高。在 ScCO2 RSM 中，蛋白质在 KOH 中的溶解度更高，而 NDICP 的水平更低。总的来说，这些结果表明在 ScCO2 提取过程中对 RSM 的热损伤较小。栽培品种没有显着的主效应，处理因素之间也没有观察到任何显着的相互作用。菜籽粕 ScCO2 产生更大的代谢能、pcPd、氮保留和能量代谢率 (p < 0.05)。无论 ORM 和品种如何，蛋白酶补充剂都会增加 pcPd (p < 0.05)。这些发现的主要意义在于，通过采用最大限度减少 RSM 对热处理的暴露的采油方法，并通过添加相容的蛋白酶，可以提高 RSM 对肉鸡的营养价值，并增加其在现代家禽生产中的利用率。05) 不考虑 ORM 和品种。这些发现的关键意义在于，通过采用将 RSM 暴露于热处理的油回收方法降至最低，并通过添加相容的蛋白酶，可以提高 RSM 对肉鸡的营养价值，并提高其在现代家禽生产中的利用率。05) 不考虑 ORM 和品种。这些发现的关键意义在于，通过采用将 RSM 暴露于热处理的油回收方法降至最低，并通过添加相容的蛋白酶，可以提高 RSM 对肉鸡的营养价值，并提高其在现代家禽生产中的利用率。