Evaluation of Zapoteca tetragona forage as alternative protein source in ruminants’ feeding

The aim of this study was to determine the nutritional characteristics of <em>Zapoteca tetragona</em> (Willd.) H. Hern to assess the suitability of this plant for ruminant nutrition. The nutritional evaluation consisted of <em>in vitro</em> and <em>in vivo</em> trials. Secondary compounds including total phenols, condensed tannin and non-protein amino acids (NPAA) were determined. Two stage <em>in vitro</em> digestibility was conducted using substrates with increasing levels of <em>Z. tetragona</em> replacing elephant grass (Pennise - tum purpureum) as control feed. The inclusion of 30% <em>Z. tetragona</em> was compared to 100% elephant grass by <em>in vitro</em> gas production technique and <em>in vivo</em> digestibility trial using sheep. Forage from <em>Z. tetragona</em> was appreciably high in crude protein (CP) and lower in neutral detergent fibre. Moreover, it was rich in Ca and P. Total phenols, condensed tannin and NPAA contents were very low. <em>In vitro</em> gas production technique showed that after 48 h incubation, the gas produced from <em>Z. tetragona</em> was higher than elephant grass (P&lt;0.05). Increasing level of <em>Z. tetragona</em> led to better dry matter (DM) and CP digestibility compared to elephant grass. <em>In vivo</em> trial showed no difference in DM intake between the two tested feed, however higher CP intake was reported when sheep fed <em>Z. tetragona</em> as well as for CP digestibility and N retention (P&lt;0.05). It can be concluded that <em>Z. tetragona</em> has a strong potential as forage crop with valuable nutritional quality. Moreover, <em>Z. tetragona</em> could represent an alternative feedstuff to conventional forage and a promising substitute fodder in tropical ecosystem.