Saro Cristina, Mateo Javier, Caro Irma, Carballo Diego Eloy, Fernández Miguel, Valdés Carmen, Bodas Raúl, Giráldez Francisco Javier
Instituto de Ganadería de Montaña, CSIC-Universidad de León, Finca Marzanas s/n, Grulleros, 24346 León, Spain.
Departamento de Producción Animal, Universidad de León, Campus Vegazana s/n, 24071 León, Spain.
Animals (Basel). 2020 Nov 21;10(11):2177. doi: 10.3390/ani10112177.
Thirty Assaf male lambs (30 ± 1.9 kg of body weight) were allocated to three groups fed diets differing in their crude protein (CP) contents (low protein (LP), 134 g CP/kg dry matter (DM); medium protein (MP), 157 g CP/kg DM; and high protein (HP), 173 g CP/kg DM) to test the effect of dietary protein content on animal performance, rumen function, animal health, and carcass and meat quality. Feed intake was recorded daily, and animals were weighed every second week. Lambs were blood-sampled to determine their acid-base status and biochemical profile. After 70 days of trial, lambs were slaughtered, and the ruminal content was collected to assess ruminal fermentation. Finally, carcass and meat quality were evaluated. Dry matter intake and average daily gain increased ( < 0.05) when increasing the level of dietary CP. There were not significant differences ( > 0.05) in the evaluated parameters in the rumen fluid of lambs. There were not significant differences in carcass or meat quality ( > 0.05) and in those parameters related to blood acid-base status. Several biochemical parameters showed differences depending on diet CP level (urea, protein, albumin, glucose, and calcium; < 0.05). Feeding costs calculated in relation to cold carcass weight decreased when dietary CP decreased. The results suggested that a dietary protein content greater than 157 g/kg DM would be required to maximize growth performance in Assaf male fattening lambs under 50 kg of body weight. However, a protein content beyond that level was not found to improve either carcass or meat quality and could worsen profitability.
30只阿萨夫雄性羔羊（体重30±1.9千克）被分为三组，分别饲喂粗蛋白（CP）含量不同的日粮（低蛋白（LP），134克CP/千克干物质（DM）；中蛋白（MP），157克CP/千克DM；高蛋白（HP），173克CP/千克DM），以测试日粮蛋白质含量对动物生产性能、瘤胃功能、动物健康以及胴体和肉质的影响。每天记录采食量，每隔一周对动物进行称重。采集羔羊血液样本以测定其酸碱状态和生化指标。试验70天后，宰杀羔羊，收集瘤胃内容物以评估瘤胃发酵。最后，评估胴体和肉质。随着日粮CP水平的提高，干物质采食量和平均日增重增加（P<0.05）。羔羊瘤胃液中评估参数无显著差异（P>0.05）。胴体或肉质以及与血液酸碱状态相关的参数无显著差异（P>0.05）。几个生化参数因日粮CP水平而异（尿素、蛋白质、白蛋白、葡萄糖和钙；P<0.05）。日粮CP降低时，按冷胴体重计算的饲养成本降低。结果表明，对于体重50千克以下的阿萨夫雄性育肥羔羊，要使其生长性能最大化，日粮蛋白质含量需大于157克/千克DM。然而，未发现超过该水平的蛋白质含量能改善胴体或肉质，反而可能降低盈利能力。
