Histomorfometria do epitélio ruminal e reticular de ovinos alimentados com dietas baseadas em palma forrageira

Abstract

The aim of this study was to evaluate the effect of diets spineless cactus genotypes resistant to the carmine cochineal on histomorphometrics variables of epithelium of rumen and reticulum of sheep. A total of 32 lambs, aged approximately 6 months and initial body weight of 21 ± 2.06 kg were used, distributed in a completely randomized design, with four treatments and eigth repetitions. The experiment lasted 73 days, with a base diet (elephantgrass hay, corn meal and soybean meal) and diets in which part of the elephantgrass hay was replaced by “miúda”, “IPA-Sertânia” or “orelha de elefante mexicana” spineless cactus. The diets were offered twice a day as a total mixed ration. The histomorphometrics variables analyzed were: keratin thickness and thickness of the nonkeratinized layers of rumen and reticulum epithelium, as well as height, width and area of the papillae of the rumen. The keratin layers of the ruminal epithelium of the animals consuming “miúda” and “orelha de elefante mexicana” spineless cactus presented greater thickening relative to the control diet: 47.31, 41.30 and 25.81 μm, respectively. The “miúda” spineless cactus caused enlargement in the keratinized layer of the reticulum epithelium, as well as a decrease in the thickness of the nonkeratinized layers of metabolically active cells. In both stomach compartments, cellular vacuolations were observed in the keratin layers, indicating a hyperkeratosis health state. The height and area of the ruminal papillae were higher in the animals that consumed the diet containing the “orelha de elefante mexicana” spineless cactus (1478.63 and 782402.02 μm, in that order). The spineless cactus changes the morphology of the ruminal and reticular epithelium of sheep, without affecting the productive performance and therefore it can be used as an alternate feeding.