Histomorphometric changes of the fore-stomach of lambs fed with diets containing spineless cactus genotypes resistant to Dactylopius sp.

The histomorphometric parameters of the fore-stomach epithelium of lambs fed with spineless cactus genotypes resistant to Dactylopius sp. were evaluated. Thirty-two lambs (23.0 ± 2.06 kg body weight) were distributed in a completely randomized design with four treatments and eight replications. The treatments consisted of the base diet and diets in which part of the elephant grass hay and all ground corn was replaced by the Miúda , IPA-Sertânia, or Orelha de Elefante Mexicana ( OEM ) spineless cacti. The keratin layers of the ruminal epithelium of the animals consuming the spineless cacti Miúda and OEM presented greater thickening relative to the control diet: 47.31, 41.30, and 25.81 μm, respectively. The heights of the ruminal papillae were higher in the animals that were fed with the OEM spineless cactus. The Miúda spineless cactus caused an enlargement in the keratinized layer of the reticulum epithelium, as well as a decrease in the thickness of the non-keratinized layers. The diet containing OEM spineless cactus resulted in greater thickening of the keratin layer of the omasal epithelium and decreased thickness of the non-keratinized layers. The spineless cacti Miúda and OEM changed the morphology of the fore-stomach epithelium and increased the dry matter intake and weight gain of lambs.