The objective of this study was to evaluate the effects of additional colostrum with different IGF-I and IgG concentrations, at 12 hours of life, on morphological characteristics of enterocytes, as well as the relationship of total amount of IGF-I ingested on the microvillus height of the calves small intestine in the first 72 hours after birth. It was utilized prolonged supply of colostrum with different concentrations, including colostrum enriched with lyophilized colostrum. Eighty two Holstein calves received, at birth, colostrum with different IgG concentrations and, at 12 hours of life, they received three colostrum pools with variable density: low colostrum (IgG and IGF-I inferior to 30 mg/mL and 90.65 µg/L, respectively), high (IgG and IGF-I superior to 100 mg/mL and 344.02 µg/L, respectively), or enriched with lyophilized colostrum (IgG and IGF-I superior to 120 mg/mL and 864.68 µg/L, respectively). At 0, 12, 24, 36, and 72 hours after birth, duodenum, proximal, medium, and distal jejunum and ileum samples were collected for ultrastructural studies. It was employed a factorial arrangement 3 × 3 + 1, corresponding to the total amount of IGF-I ingested in colostrum meals (0-500, 500-1500, 1500-2500 µg), three slaughter ages (at 10, 24 and 72 hours of life) and control group (at birth) for determination of the microvillus height. Different morphologic characteristics of the enterocytes were observed as consequence of the age, IgG and IGF-I ingested. The total IGF-I amount ingested showed positively local effect on the microvillus height of the intestinal.
immunoglobulin; insulin like growth factor-I; microvillus; morphology; morphometry; transmission electronic microscopy
