Department of Animal Production and Health, Veterinary Public Health and Food Science and Technology (PASAPTA), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, 46113, Valencia, Spain.
Institute of Agrifood Research and Technology (IRTA)-Animal Breeding and Genetics, Caldes de Montbui, Barcelona, Spain.
Sci Rep. 2024 Nov 25;14(1):29180. doi: 10.1038/s41598-024-80701-x.
Feed restriction is a common nutritional practice in rabbit farming; however, decreased feed intake can also signal potential digestive disorders at an early stage. This study endeavors to investigate the impact of feed restriction on selected productive traits and the urinary metabolome of juvenile rabbits across diverse genetic backgrounds. Our objective is to identify potential biomarkers capable of detecting periods of fasting. A total of 48 growing rabbits were used from two genetic types: Prat line (selected for litter size at weaning, n = 24) and Caldes line (selected for post-weaning growth rate, n = 24). At 60 days of age, a digestibility trial was carried out. Changes in productive traits (through bioelectrical impedance analysis, live weight control, average daily gain, energy, and protein retention) were evaluated when the animals were fed ad libitum from 60 to 64 days of age and when the same animals were subjected to feed restriction (50% of maintenance energy requirements) from 70 to 74 days of age, in a split-plot trial. In addition, untargeted urine metabolomics analysis was performed at both periods (ad libitum vs. restricted). Although some differences between genetic lines were observed in the animals' performance traits (average daily gain and retention of energy and protein), no differences in the urine metabolome were found between genetic types. However, feed restriction caused notable changes in the metabolome. When the animals were subjected to feed restriction, they had higher levels of ascorbic acid (P = 0.001) and p-cresol sulphate (P = 0.058) and lower levels of pyrocatechol sulphate/hydroquinone sulphate (P < 0.001), resorcinol sulphate (P = 0.002), enterolactone sulphate (P < 0.001), enterolactone (P < 0.001), kynurenic acid (P = 0.0002), proline betaine (P < 0.001), pipecolic acid betaine (P < 0.001), xanthurenic acid (P < 0.001) and quinaldic acid (P < 0.001) than the same animals when they were fed ad libitum. This study proposes urine ascorbic acid as potential biomarker for fasting events in rabbits. As urine ascorbic acid is the sole metabolite that significantly increases in the restricted group, it offers promising indicator for early detection and targeted management of digestive disorders in rabbits.
限饲是兔养殖中常见的营养管理措施，但采食量下降也可能早期提示潜在的消化紊乱。本研究旨在探究限饲对不同遗传背景下幼兔生产性能和尿液代谢组的影响，以期寻找潜在的可用于检测禁食阶段的生物标志物。研究共选用了两个遗传类型的 48 只生长兔：Prat 系（断奶窝重选择，n=24）和 Caldes 系（断奶后生长速度选择，n=24）。60 日龄时进行消化试验，60-64 日龄自由采食，70-74 日龄限饲（50%维持能量需求），通过生物电阻抗分析、活体称重控制、平均日增重、能量和蛋白质保留率评估生产性能变化。此外，在两个时期（自由采食与限饲）进行非靶向尿液代谢组分析。尽管遗传类型间幼兔生产性能（平均日增重和能量、蛋白质保留）存在差异，但遗传类型间尿液代谢组无差异。然而，限饲引起代谢组明显变化。限饲时，动物尿液中抗坏血酸（P=0.001）和对甲酚硫酸盐（P=0.058）水平升高，焦儿茶酚硫酸盐/对苯二酚硫酸盐（P<0.001）、间苯二酚硫酸盐（P=0.002）、肠内酯硫酸盐（P<0.001）、肠内酯（P<0.001）、犬尿氨酸（P=0.0002）、脯氨酸甜菜碱（P<0.001）、哌可酸甜菜碱（P<0.001）、黄尿酸（P<0.001）和喹哪啶酸（P<0.001）水平降低。与自由采食时相比，限饲组动物尿液中这些物质含量更高。本研究提出尿液抗坏血酸可作为兔禁食事件的潜在生物标志物。由于限饲组尿液抗坏血酸是唯一显著升高的代谢物，因此它是兔早期检测和消化紊乱靶向管理的有前景的标志物。
