To examine the relationship of
insulin and
glucose, broiler embryos were subjected to acute or prolonged
hypoglycemia during the late embryonic phase by, respectively, injecting once (at embryonic day [ED] 16 or 17) or on 3 consecutive days (ED 16, 17, and 18) with
tolbutamide (80 μg/g embryo weight), a substance that stimulates insulin secretion from the pancreas. After 1
tolbutamide injection, a prolonged (32 h) decrease of plasma
glucose and a profound acute increase in plasma
insulin were observed. The 3 consecutive
tolbutamide injections induced
hypoglycemia for 4 days (from ED 16 to ED 19). The postnatal performance after 3 consecutive
tolbutamide injections in broiler embryos was also investigated.
Body weight was lower in
tolbutamide-treated chickens from hatch to 42 d compared with
sham (P = 0.001) and control (P < 0.001) chickens. Feed intake was lower in the
tolbutamide group from hatch to 42 d as compared with
sham (P = 0.007) and control (P = 0.017) animals. In addition, at 42 d, plasma
glucose concentrations, after an
insulin injection challenge (50 μg/kg
body weight), were higher in
tolbutamide-treated chickens compared with the
sham and the control group as were their basal
glucose levels (P value of group effect <0.001). In conclusion,
tolbutamide treatment during the late embryonic development in broilers resulted in prolonged
hypoglycemia in this period and negatively influenced the posthatch performance.