Effects of Mesenteric Injection on the Physiological Traits of Broiler Chickens During the Hatching Window

This study aimed to evaluate the effects of mesenteric injection and administration method during the hatching window on early physiological responses and lipid metabolism in broiler chickens.A total of 600 one-day-old ROSS 308 chicks were allocated to a 2 × 5 factorial design, including two hatching windows (before and after 493 h) and five administration methods (mesenteric or intra-crop delivery of electrolytes or water, and a non-treated control).Blood lipid-related metabolites were assessed at 1 and 11 days of age.At hatch, a significant (P < 0.05) interaction between hatching window and administration method influenced serum lipid profiles.Water gavage resulted in higher glucose, triglycerides, very low-density lipoproteins (VLDL), and low-density lipoproteins (LDL) concentrations, indicating rapid post-hatch energy mobilization, whereas mesenteric electrolyte injection reduced undesirable fat indicators, reflecting improved ionic balance and metabolic regulation.The hatching window alone had no significant independent effect.By day 11, glucose levels were unaffected, while cholesterol fractions and triglycerides responded significantly (P < 0.05) to treatments.Electrolyte administration increased high-density lipoprotein (HDL) levels and reduced triglycerides (TG) and VLDL concentrations, suggesting enhanced lipid redistribution and metabolic stability during early growth.Overall, the findings demonstrate that the method of early post-hatch administration plays a more decisive role than hatching window in regulating lipid metabolism, with potential implications for improving metabolic health and early growth efficiency in broiler chickens.