Effects of Different Dietary Energy and Protein Levels on Growth Performance, Serum Metabolites and AMPK Gene Expression in Japanese Quail

This study was conducted to examine the effects of different dietary metabolizable energy (ME) and crude protein (CP) levels on growth performance, carcass quality, blood metabolites, and adenosine monophos-phate kinase (AMPK) gene expression in Japanese quails. The experiment employed a 2 ME (2900 and 3200 kcal/kg of diet) × 3 CP (24, 26, and 28%) factorial arrangement within a completely randomized de-sign, resulting in six treatments, each replicated five times with 25 birds per replicate. At the end of the experiment (day 35), two birds were bled through the wing vein to assess blood biochemical parameters and were subsequently sacrificed to determine carcass traits. The energy content significantly influenced the feed intake (P≤0.05). The highest feed intake was found in quails fed diets with 2900 kcal ME/kg, while the lowest intake was in those fed diets with 3200 kcal ME/kg. The feed conversion ratio was affected by die-tary energy levels (P≤0.05). The highest and lowest feed conversion ratio (FCR) values were found in diets with energy contents of 2900 and 3200 kcal ME/kg, respectively (P<0.05). Dietary energy content signifi-cantly affected triglyceride (TG) and cholesterol levels (P≤0.05). The Lowest level of TG was observed in diets with 3200 kcal ME/kg (P<0.05). Dietary protein levels also significantly influenced TG concentration (P≤0.05). The lowest amount was recorded in the diet containing 28% CP. The high density lipoprotein-cholesterol (HDL-C) levels were affected by the dietary protein content, with the highest plasma HDL-C levels observed in diets with 24% CP (P<0.05). Breast muscle fat was significantly influenced by dietary energy levels (P<0.05), and birds consumed diets with 2900 kcal ME/kg showed a decrease in their fat con-tent of breast muscle. The interaction effect between ME and CP was significant for breast muscle fat (P<0.05). The highest fat content in the breast muscle was observed in quails fed a diet containing 3200 kcal ME/kg and 28% CP. The moisture content of the breast muscle was also significantly affected by die-tary energy content (P≤0.05) and treatments with 2900 kcal ME/kg resulted in higher breast muscle mois-ture content (P<0.05). AMPK expression in the breast muscle increased significantly (P < 0.05) in the diets with 2900 kcal ME/kg and 26% CP.