S-Adenosylmethionine (SAM) is the major endogenous methyl donor for methyltransferase reactions, while 5-Azacytidine (AZA) is a synthetic drug inhibiting DNA methyltransferase activity. Both molecules can thus influence DNA methylation patterns in an organism and thereby affect gene expression and ultimately behavior in the long-term. Whether or not effects on behavior are exerted on a shorter time scale is unclear. The goal of this study was to explore the direct effects of SAM and AZA on appetite regulation, using broiler chicken and Japanese quail as the animal models. Fed or 180 min-fasted broilers (at day 4 post-hatch) or 360 min-fasted quail (at day 7 post-hatch) were intracerebroventricularly injected with SAM or AZA and food intake was measured for 360 min. For broilers, there was no effect of AZA, at any dose, on food intake in either fed or fasted chicks at any time point. In contrast, 1 and 10 µg doses of SAM reduced food intake in fed chicks at 60 min post-injection. In fasted chicks, although there were no differences for the first 30 min post-injection, SAM suppressed food intake during the second 30-min period. For quail, however, AZA (25 µg dose) decreased food intake at 60 and 150–360 min post-injection in fasted birds. A reduction in food intake was also observed at 120- and 360-min post-injection in fed quail in response to 5 and 25 µg doses of AZA, respectively. SAM had no effect when quail were fasted, whereas 1 µg dose of SAM suppressed food consumption in fed quail during the third 30-min period. Thus, when administered directly into the central nervous system, SAM may act as a transient appetite suppressant in both broilers and quail, whereas the direct inhibitory effect of AZA on food consumption depends on species and nutritional states.

S-腺苷甲硫氨酸 (SAM) 是甲基转移酶反应的主要内源性甲基供体，而 5-氮杂胞苷 (AZA) 是抑制 DNA 甲基转移酶活性的合成药物。因此，这两种分子都可以影响生物体中的 DNA 甲基化模式，从而影响基因表达并最终影响长期行为。对行为的影响是否会在更短的时间范围内发挥作用尚不清楚。本研究的目的是探索 SAM 和 AZA 对食欲调节的直接影响，使用肉鸡和日本鹌鹑作为动物模型。饲喂或禁食 180 分钟的肉鸡（孵化后第 4 天）或禁食 360 分钟的鹌鹑（孵化后第 7 天）脑室内注射 SAM 或 AZA，并测量 360 分钟的食物摄入量。对于肉鸡，任何剂量的 AZA 都没有影响，任何时间点喂食或禁食小鸡的食物摄入量。相比之下，在注射后 60 分钟，1 和 10 µg 剂量的 SAM 可减少饲喂小鸡的食物摄入量。在禁食的小鸡中，虽然在注射后的前 30 分钟没有差异，但 SAM 在第二个 30 分钟期间抑制了食物摄入。然而，对于鹌鹑，AZA（25 µg 剂量）在注射后 60 分钟和 150-360 分钟减少了禁食鸟类的食物摄入量。在喂食鹌鹑后 120 分钟和 360 分钟也观察到食物摄入量减少，分别响应于 5 和 25 微克剂量的 AZA。SAM 在鹌鹑禁食时没有影响，而 1 µg 剂量的 SAM 在第三个 30 分钟期间抑制了喂食鹌鹑的食物消耗。因此，当直接给予中枢神经系统时，SAM 可作为肉鸡和鹌鹑的短暂食欲抑制剂，