RESUMO
Method according to DIRSTINE (1968) was employed to study the activities of serum and liver lipase in White Leghorn cockerels during early post-incubation ontogenesis; as to serum lipase, two embryo intervals were also studied (the 13th and 20th day of incubation). From the average value of 4.4 ummol (13th day), serum lipase activity increased to the average value of 7.5 ummol (20th day). The first day after hatching the average value was 3.5 ummol which remained almost unchanged until the 9th day, with the exception of a slight drop the third day; an increase of activities was observed on the 13th day (4.9 ummol), 15th day (3.5 ummol), 21st day (7.6 ummol), 22nd day (5.5 ummol), and 24th day (8.8 ummol). The minimum average activity of 2.5 ummol was measured the 32nd day. Liver lipase activity was observed to drop from the first-day starting value of 20.6 ummol to 9.8 ummol (the second day), with a subsequent increase to 14.9 ummol (the 4th day). The maximum values were recorded the 13th day (26.2 ummol) and the 15th day (28.7 ummol) whereas the minimum average value was obtained the 32nd day (6.3 ummol). Liver lipase activity drop on the second day of age and serum lipase activity drop on the third day with subsequent increase are probably associated with the change from yolk-sac nutrition to feeding per os. Some stabilization of serum and liver lipase occurs the 32nd day; the values found in adult fowl were almost the same as the 32nd day values.