In Belgium, crossing a hybrid dam with a Piétrain sire leads to a rather lean and meaty fattening pig type. A digestibility trial and a performance trial were carried out to determine protein needs of this pig type. Six experimental diets with increasing protein content were formulated with 0.65–1.25% apparent ileal digestible lysine. The feeds were formulated to the ideal protein composition, with lysine as the reference amino acid. Standardised and apparent digestible amino acid values of the extreme diets were measured in a digestibility trial with four gilts cannulated at the end of the ileum, with an average initial and final BW of 39.1 kg and 55.3 kg, respectively, using a protein-free feed to estimate the basal endogenous N-losses. A performance trial at 13–18 weeks of age (40–70 kg BW) was performed with barrows and gilts separately at six protein levels, balanced in lysine, threonine, methionine and tryptophan. The experiment consisted of 11 pens (of 5 animals) per treatment and per sex. Average daily gain (ADG) and feed conversion ratio (FCR) reached maximal performance within the experimental lysine range for both sexes. Based on the ADG-data for barrows and on the ADG- and FCR-data for gilts, a protein level for optimal performance corresponded with a standardised ileal digestible lysine concentration of 0.89% for barrows and of 1.07–1.09% for gilts.

中文翻译：

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40-70 公斤的公猪和小母猪对增加日粮中理想蛋白质浓度的反应

在比利时，将杂交母猪与皮特兰公猪杂交会培育出相当瘦且多肉的育肥猪。进行了消化率试验和性能试验以确定这种猪的蛋白质需求。用 0.65-1.25% 的回肠表观可消化赖氨酸配制六种蛋白质含量增加的实验日粮。饲料被配制成理想的蛋白质组成，赖氨酸作为参考氨基酸。在消化率试验中测量了极端日粮的标准化和表观可消化氨基酸值，四头小母猪在回肠末端插管，平均初始和最终体重分别为 39.1 kg 和 55.3 kg，使用无蛋白质饲料估计基础内源性 N 损失。在 13-18 周龄（40-70 公斤体重）时，分别在六种蛋白质水平上对公猪和小母猪进行了性能试验，平衡了赖氨酸、苏氨酸、蛋氨酸和色氨酸。实验由每个处理和每个性别的 11 个围栏（5 只动物）组成。在实验赖氨酸范围内，两性的平均日增重 (ADG) 和饲料转化率 (FCR) 都达到了最大性能。根据公猪的 ADG 数据以及小母猪的 ADG 和 FCR 数据，最佳性能的蛋白质水平对应于公猪的 0.89% 和小母猪的 1.07–1.09% 的标准化回肠可消化赖氨酸浓度。在实验赖氨酸范围内，两性的平均日增重 (ADG) 和饲料转化率 (FCR) 都达到了最大性能。根据公猪的 ADG 数据以及小母猪的 ADG 和 FCR 数据，最佳性能的蛋白质水平对应于公猪的 0.89% 和小母猪的 1.07–1.09% 的标准化回肠可消化赖氨酸浓度。在实验赖氨酸范围内，两性的平均日增重 (ADG) 和饲料转化率 (FCR) 均达到最高性能。根据公猪的 ADG 数据以及小母猪的 ADG 和 FCR 数据，最佳性能的蛋白质水平对应于公猪的 0.89% 和小母猪的 1.07–1.09% 的标准化回肠可消化赖氨酸浓度。