a Department of Animal and Poultry Sciences , Virginia Polytechnic Institute and State University , Blacksburg , VA , USA.
Nutr Neurosci. 2018 Jul;21(6):403-413. doi: 10.1080/1028415X.2017.1296606. Epub 2017 Mar 10.
The objective of this study was to determine the influence of dietary macronutrient composition on central NPY's orexigenic effect in chicks.
Day-of-hatch chicks were fed one of three diets (3000 kcal ME/kg) ad libitum from hatch: high carbohydrate (HC), high fat (HF; 30% ME derived from soybean oil), and high protein (HP; 25 vs. 22% CP). In Experiment 1, chicks received intracerebroventricular injections of 0 (vehicle), 0.2, or 2.0 nmol NPY on day 4 and food intake was recorded for 6 hours. In Experiment 2, chicks were given all three diets before and after injection. In Experiment 3, hypothalamus was collected at 1-hour post-injection for gene expression analysis.
The HC diet-fed chicks responded with a greater increase, while the chicks fed the HF diet had a lower threshold response in food intake to NPY. Neuropeptide Y dose-dependently increased food intake in chicks fed the HC and HP diets. Chicks administered 0.2 nmol NPY preferred the HC and HP diets over the HF diet. Relative quantities of hypothalamic NPYR1 and MC4R mRNA were reduced by NPY in chicks that consumed the HP and HC diets, respectively.
Consumption of the HC diet was associated with the most robust NPY-induced increase in food intake. Injection of NPY accentuated differences among dietary groups in hypothalamic gene expression of several appetite-associated factors, results suggesting that the NPY/agouti-related peptide and melanocortin pathways are associated with some of the diet- and NPY-induced differences observed in this study.
本研究旨在确定日粮宏量营养素组成对雏鸡中枢 NPY 食欲作用的影响。
从出雏开始，雏鸡自由采食三种日粮（3000kcal ME/kg）：高碳水化合物（HC）、高脂肪（HF；30%ME 来源于豆油）和高蛋白（HP；25%CP 比 22%CP）。在实验 1 中，雏鸡在第 4 天接受 0（载体）、0.2 或 2.0nmol NPY 脑室注射，并记录 6 小时的食物摄入量。在实验 2 中，在注射前后雏鸡给予三种日粮。在实验 3 中，在注射后 1 小时收集下丘脑进行基因表达分析。
HC 饮食喂养的雏鸡对 NPY 的反应表现出更大的增加，而 HF 饮食喂养的雏鸡对食物摄入的阈值反应较低。NPY 呈剂量依赖性地增加了 HC 和 HP 饮食喂养的雏鸡的食物摄入量。给予 0.2nmol NPY 的雏鸡更喜欢 HC 和 HP 饮食，而不是 HF 饮食。接受 HP 和 HC 饮食的雏鸡下丘脑 NPYR1 和 MC4R mRNA 的相对数量分别被 NPY 减少。
摄入 HC 饮食与 NPY 诱导的食物摄入量增加最为显著。NPY 注射突出了在几种与食欲相关的因素的下丘脑基因表达中，日粮组之间的差异，结果表明 NPY/刺鼠相关肽和黑皮质素途径与本研究中观察到的一些饮食和 NPY 诱导的差异有关。
