Ruminal and morphometric parameters of the rumen and intestines of sheep fed with increasing levels of spineless cactus (Nopalea cochenillifera Salm-Dyck)

Abstract

The objective of this study was to evaluate the ruminal parameters (pH, N-NH 3, and microbial protein) and morphometry of the rumen and intestine of sheep fed with a diet containing four different levels of the spineless cactus variety, Baiana. The experiment was conducted at the National Semi-Arid Institute in Campina Grande, PB, Brazil. A total of 40 male sheep submitted to the confinement regime were used in a completely randomized design with four treatments (0, 15, 30, and 45% dry matter basis) and ten replicates, with an initial body weight of 23.7 ± 3.08 kg. Experimental diets were composed of ground corn, soybean meal, urea, mineral supplement, limestone, Tifton 85 hay, and spineless cactus of the Baiana variety. The pH, ammonia nitrogen, and microbial protein were evaluated in the ruminal fluid, alongside the morphometric characteristics of the rumen and intestine. While the addition of the spineless cactus did not affect N-NH 3 , it caused a linear reduction in the ruminal pH following 4 h of feeding, and also increased the microbial protein. In addition, it stimulated a reduction in the height of the papillae and the muscle layer of the rumen, and induced the mucosal height in the intestine to increase. The addition of up to 30% of spineless cactus in the diet of sheep without a defined breed did not alter the N-NH 3 , pH, and ruminal histology, but it did increase the production of microbial protein and intestinal mucosa.