Nutrition-related histopathology of the intestine of milkfish Chanos chanos fry

A histopathological study was conducted on the intestine of milkfish larvae Chanos chanos, subjected to different nutritional conditions. Newly caught milkfish fry, ca 20 d old, were starved for 7 d and then fed with either Artemia nauplii or Chlorefla sp. The latter diet, as already shown in other studies, is detrimental to young milkfish. A third, control, group of fry was starved for a further 2 d. In larvae fed with Artemia, 1 to 2 h after feeding, intensive hpid absorption was noted m the first part of the intestine (Intestine I , lipid-absorbing zone, midgut). The second part of the intestine (Intestine 11, hmdgut) was characterized by pinocytotic activity and the presence of large supranuclear vacuoles. Food deprivation for 9 d resulted in cellular hydrahon, transformation of rmtochondria, disturbances of the basal labyrinth and appearance of autolytic vacuoles in enterocyte cytoplasm in Intestine I , with a proximo-distal gradient of severity of enterocytic degeneration. In Intestine 11, supranuclear vacuoles were replaced by dense bodies; pinocytotlc achvity was maintained at a reduced level. Microvllli were fragmented over the whole length of the intestine. Chlorella-fed larvae, although containing broken algae withln the gut lumen, displayed no signs of nutrient absorption as detectable by electron microscopy. In Intestine I, enterocytes contained bizarre nuclei, an enhanced number of lysosomes and occasionaLly large intracellular vacuoles. In addition, intercellular spaces were dilated. Mitochondria appeared pale and swollen throughout the gut. Histological alterations in Intestine I1 were similar to those for starved fry.