Evaluation of Zapoteca tetragona Forage as Alternative Protein Source in Ruminants’ Feeding

Abstract

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