Department of Animal Production and Health, Veterinary Public Health and Food Science and Technology (PASAPTA), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, Valencia, Spain.
Departamento de Botánica, Ecología y Fisiología Vegetal, Ecology Area, Faculty of Science, University of Córdoba, Cordoba, Spain.
J Anim Physiol Anim Nutr (Berl). 2023 Sep;107(5):1294-1301. doi: 10.1111/jpn.13826. Epub 2023 May 1.
The ecological interest in the European rabbit (Oryctolagus cuniculus) has grown since it was declared an endangered species. Nutrition is fundamental in its dispersion and the key to its success. This is the main reason why knowledge of their nutritional preferences/requirements could play a fundamental role in rabbit biology and, therefore, in their conservation. The objectives of the work will be to elucidate how age and sex affect both nutritional preferences/requirements, and the nutrient optimisation of European rabbits. To address this gap, 70 wild European rabbits were studied. The rabbits were divided according to their age: adult (n = 43) and young (n = 27). Two groups were differentiated according to the adult rabbits' sex: females (n = 28) and males (n = 15). We analysed the relative (%) and absolute (g) chemical composition of the rabbits' gastric contents: dry matter (DM), ashes (ASH), crude protein (CP), ether extract (EE), neutral detergent fibre (NDF), acid detergent fibre (ADF), and lignin, hemicelluloses and celluloses, highly digestible nonnitrogenous nutrients (HDNN: fat, starch, and soluble fibre), well from the blood was analysed with plasmatic urea nitrogen (PUN), nonesterified fatty acid (NEFA) and glucose (GLU). As a nutrient optimisation measure, the following indices between blood metabolites and stomach content were calculated: PUN/CP total content, NEFA/DM total content and GLU/DM total content ratios. Our works showed that age and sex affected the nutritional strategy of rabbits. Regarding age: adults showed lower CP (-14%; p = 0.0217) and higher HDNN (+21%; p = 0.0399) relative content than young rabbits, and absolute amount of most nutrients: DM (+59%; p = 0.001), OM (+43%; p = 0.0049), ASH (+54%; p = 0.0085), Hemicelluloses (+73%; p = 0.0084), Cellulose (+27%; p = 0.0452), and HDNN (+63%; p = 0.0012). In addition, adults showed better nutrient optimisation. Sex did not affect the relative chemical composition of the gastric content, but it showed a clear higher gastric content by females (+85%; p < 0.0001) and higher intake of most of the absolute chemical components: DM (+64%; p < 0.001), CP (+56%; p = 0.0005), OM (+58%; p = 0.0001), ASH (+44%; p = 0.0123), HDNN (+39%; p = 0.001), NDF (+59%; p = 0.001), ADF (+64%; p = 0.0003), lignin (+82%; p = 0.0036) and cellulose (+58%; p = 0.0002). Finally, we observed that females had better nutrient optimisation than males. This works supports the idea that feeding ecology and nutrition are particularly relevant to reproductive success and fitness in wild animals.
对欧洲兔（Oryctolagus cuniculus）的生态兴趣自其被宣布为濒危物种以来一直在增长。营养是其扩散的基础，也是其成功的关键。这就是为什么了解它们的营养偏好/需求可能在兔子生物学中发挥重要作用，因此在其保护中发挥重要作用的主要原因。该工作的目的将阐明年龄和性别如何影响营养偏好/需求以及欧洲兔的营养优化。为了解决这一差距，研究了 70 只野生欧洲兔。根据年龄将兔子分为：成年（n=43）和幼年（n=27）。根据成年兔的性别将两组区分开来：雌性（n=28）和雄性（n=15）。我们分析了兔子胃内容物的相对（%）和绝对（g）化学成分：干物质（DM）、灰分（ASH）、粗蛋白（CP）、乙醚提取物（EE）、中性洗涤剂纤维（NDF）、酸性洗涤剂纤维（ADF）和木质素、半纤维素和纤维素，从血液中分析了血浆尿素氮（PUN）、非酯化脂肪酸（NEFA）和葡萄糖（GLU）。作为营养优化措施，计算了血液代谢物和胃内容物之间的以下指数：PUN/CP 总含量、NEFA/DM 总含量和 GLU/DM 总含量比。我们的研究表明，年龄和性别影响兔子的营养策略。关于年龄：成年兔的 CP 相对含量较低（-14%；p=0.0217），HDNN 相对含量较高（+21%；p=0.0399），绝对含量的大多数营养素：DM（+59%；p=0.001），OM（+43%；p=0.0049），ASH（+54%；p=0.0085），半纤维素（+73%；p=0.0084），纤维素（+27%；p=0.0452）和 HDNN（+63%；p=0.0012）。此外，成年兔表现出更好的营养优化。性别不影响胃内容物的相对化学成分，但雌性的胃内容物明显更高（+85%；p<0.0001），并且摄入了大多数绝对化学成分：DM（+64%；p<0.001），CP（+56%；p=0.0005），OM（+58%；p=0.0001），ASH（+44%；p=0.0123），HDNN（+39%；p=0.001），NDF（+59%；p=0.001），ADF（+64%；p=0.0003），木质素（+82%；p=0.0036）和纤维素（+58%；p=0.0002）。最后，我们观察到雌性的营养优化优于雄性。这项工作支持这样一种观点，即饮食生态和营养对野生动物的繁殖成功和适应性特别重要。
