Pancreatic amylase | Negligible activity prenatally and at birth but detected by 1 mo postnatally and reaches adult levels by weaning (Lebenthal and Lee, 1980) | Present at birth for first feeding, but then steep decline (Robberecht et al., 1971; Mubiru and Xu, 1998) | Rapid increase postnatally in pigs (Mubiru and Xu, 1998) | In dogs, first detected after 3 wk, but relatively low through weaning (Buddington et al., 2003) |
Pancreatic lipase | Negligible at birth (Lebenthal and Lee, 1980) | Present at birth for first feeding, but then steep decline until weaning (Robberecht et al., 1971; Mubiru and Xu, 1998) | Present and active at birth in pigs with steep increase in activity at 3–4 wk; primary source of lipase activity (Pierzynowski et al., 1995; Jensen et al., 1997; Mubiru and Xu, 1998; Li et al., 2001) | Not detected until 6 wk, but reaches adult levels by 9 wk postnatal (Buddington et al., 2003) |
Carboxypepdidase B | Relatively low prenatally and at birth (Lebenthal and Lee, 1980) | | Not specifically reported |
Trypsin | Present and active from birth (Lebenthal and Lee, 1980) | Present and presumed active at birth for first feeding, but then steep decline until weaning (Robberecht et al., 1971; Mubiru and Xu, 1998) | Present and active at birth, with increased activity postnatally (Harada et al., 1988; Jensen et al., 1997; Mubiru and Xu, 1998) | In dogs, relatively high activity during suckling (Buddington et al., 2003) |
Chymotrypsin | Present and active from birth (Lebenthal and Lee, 1980) | Present at birth for first feeding, but then steep decline until weaning (Robberecht et al., 1971; Mubiru and Xu, 1998) | Present and active at birth with increased activity postnatally (Harada et al., 1988; Jensen et al., 1997; Mubiru and Xu, 1998) | Low at birth in dogs, with increase through 3 wk postnatal, and secondary increase after weaning (Buddington et al., 2003) |