Norambuena Cecilia, Hernandez Francisca, Alfaro Jorge, Silva Gonzalo, Topp Shirley, Ratto Marcelo
Department of Veterinary Science and Public Health, Faculty of Natural Resources, Catholic University of Temuco, Temuco, Chile.
Nucleus of Research in Food Production, Faculty of Natural Resources, Catholic University of Temuco, Temuco, Chile.
Front Vet Sci. 2020 Dec 16;7:598147. doi: 10.3389/fvets.2020.598147. eCollection 2020.
The objective was to determine the effect of energy diet restriction on energy balance, systemic leptin and corpus luteum (CL) vascularization, development, and function in South American camelids. In experiment 1, adult llamas were randomly assigned to receive a diet of 70% of their maintenance energy requirements (MER) (Restricted group, = 7) or fed (Control group, = 7) during 28 days. Body live weight (BLW) and body condition score (BCS) were recorded, blood samples were collected every 2 weeks to measure plasma leptin concentrations, and energy metabolites were quantified. In experiment 2, adult alpacas were randomly assigned to receive a diet of 40% MER for 21 days (Restricted group, = 7) or fed (Control group, = 7). Then, ovulation was induced with gonadorelin acetate (day = 0), and trans-rectal ultrasonography (7.5 MHz) was performed using B and Doppler mode to record the diameter of the pre-ovulatory follicle, ovulation, CL diameter, and vascularization from Days 0 to 13. Blood samples were collected every 48 h from Days 1 to 13 to quantify plasma leptin and progesterone concentrations. In experiment 1, energy diet restriction of 70% MER did not affect plasma leptin concentration and metabolic parameters of the Restricted group. In experiment 2, the Restricted group had a lower BCS ( < 0.001), a smaller diameter of the CL on Days 5 and 7 ( < 0.05), and a smaller maximum diameter of the CL (10.2 ± 0.6 mm) than the Control group (12.1 ± 0.6 mm; = 0.04). Low energy restriction of 70% MER for 28 days did not affect the energy balance of llamas (Experiment 1). Moderate energy restriction of 40% MER for 21 days negatively affected energy balance (BCS), and CL development but not its vascularization, leptin, and progesterone concentrations. These species must be submitted to longer periods or a higher level of energy restriction to impair ovarian function.
目的是确定能量饮食限制对南美骆驼科动物能量平衡、全身瘦素以及黄体（CL）血管生成、发育和功能的影响。在实验1中，成年美洲驼被随机分配，在28天内接受维持能量需求（MER）70%的饮食（限制组，n = 7）或正常喂食（对照组，n = 7）。记录活体体重（BLW）和体况评分（BCS），每2周采集血样以测量血浆瘦素浓度，并对能量代谢物进行定量分析。在实验2中，成年羊驼被随机分配，接受21天MER 40%的饮食（限制组，n = 7）或正常喂食（对照组，n = 7）。然后，在第0天用醋酸戈那瑞林诱导排卵，并使用B型和多普勒模式进行经直肠超声检查（7.5 MHz），记录从第0天到第13天排卵前卵泡直径、排卵情况、CL直径和血管生成情况。从第1天到第13天，每48小时采集血样以定量分析血浆瘦素和孕酮浓度。在实验1中，70% MER的能量饮食限制不影响限制组的血浆瘦素浓度和代谢参数。在实验2中，限制组的BCS较低（P < 0.001），在第5天和第7天CL直径较小（P < 0.05），且CL的最大直径（10.2±0.6 mm）小于对照组（12.1±0.6 mm；P = 0.04）。28天70% MER的低能量限制不影响美洲驼的能量平衡（实验1）。21天40% MER的中度能量限制对能量平衡（BCS）和CL发育有负面影响，但对其血管生成、瘦素和孕酮浓度没有影响。这些物种必须接受更长时间或更高水平的能量限制才能损害卵巢功能。
