Abstract
The objective of the study was to investigate the effects of Eimeria infection on expression of genes and proteins related to feed intake and core body temperature in broilers. A total of 750 fifteen-day-old male broilers were distributed to five experimental groups in a completely randomized design (CRD) with 6 replicates of 25 birds per pen. The five experimental groups included (1) unchallenged control (UNC); (2) Eimeria challenge 1 (EC1): challenged with 31,250 E. acervulina, 6,250 E. maxima, 6,250 E. tenella; (3) Eimeria challenge 2 (EC2): 2 × EC1; 4) Eimeria challenge 3 (EC3): 2 × EC2; and 5) Eimeria challenge 4 (EC4): 2 × EC3. Feed intake was linearly decreased by increased doses of Eimeria spp. in broilers at 6 days post inoculation (dpi) (P < 0.05). Core body temperature was linearly reduced by higher doses of Eimeria spp. in broilers (P < 0.05). Relative mRNA expression of agouti-related protein (AGRP) (P < 0.05), interleukin 18 (IL18) (P < 0.05), motilin receptor (MR) (P < 0.01), and proopiomelanocortin (POMC) (P < 0.01) was linearly decreased by higher doses of Eimeria spp. in the brain. Relative mRNA expression of cholecystokinin (CCK), motilin, neuropeptide Y (NPY), neuropeptide Y receptor Y1 (NPYY1) was linearly decreased by higher doses of Eimeria spp. in the duodenum (P < 0.05). Higher doses of Eimeria spp. significantly increased relative mRNA expression of cold-inducible RNA-binding protein (CIRBP), hypoxia inducible factor 1 subunit alpha (HIF1A), and heat shock protein 70 (HSP70) in the duodenum. Higher doses of Eimeria spp. linearly and quadratically decreased relative mRNA expression of CCK (P < 0.01), and relative mRNA expression of motilin and NPYY2 was linearly decreased by higher doses of Eimeria spp. in the jejunum (P < 0.05). Higher doses of Eimeria spp. linearly increased protein concentration of CCK in the serum (P < 0.05). Hence, Eimeria infection modulated expression of genes and proteins related to feed intake and core body temperature in broilers.