NUTRITIONAL COMPOSITION OF Arceuthobium vaginatum subsp. vaginatum AND A. globosum subsp. grandicaule AND THEIR EFFECT ON IN VITRO RUMINAL FERMENTATION KINETICS

Abstract

<p><strong>Background</strong>: <em>Arceuthobium vaginatum</em> subsp. <em>vaginatum</em> (BM; black mistletoe) and <em>Arceuthobium globosum</em> subsp. <em>grandicaule</em> (YM; yellow mistletoe), are two parasitic plant species abundant in the forests of northern and central Mexico and Central America, affect 43% of the <em>P. </em><em>hart</em><em>wegii</em> tree population in the Nevado de Toluca Flora and Fauna Protection Area (NTFFPA), including mistletoe as a complementary feed in sheep can reduce the environmental impact generated by these pests to the forest and also reduce the purchase of feed for livestock. <strong>Objective</strong>: To evaluate the chemical composition, phenolic content and <em>in vitro</em> fermentation kinetics of two mistletoe species (M) <em>Arceuthobium vaginatum</em> subsp. <em>vaginatum</em> (BM; black mistletoe) and <em>A. globosum</em> subsp. <em>grandicaule</em> (YM; yellow mistletoe), in four age categories (AC) of <em>Pinus hartwegii</em> (AC: small sapling, large sapling, juvenile and adult) collected in the Nevado de Toluca Flora and Fauna Protection Area (NTFFPA). <strong>Methodology</strong>: The chemical composition (dry matter DM; neutral detergent fiber NDF; acid detergent fiber ADF and crude protein CP), phenolic content (total phenols TP; total tannins TT and condensed tannins, CT), <em>in vitro</em> fermentation kinetics parameters and <em>in vitro</em> digestibility were analysed. The experimental design used was completely randomized design with 2x4 factorial arrangement. <strong>Results</strong>: DM content was different between M (P< 0.05), the highest was found in BM. The NDF and ADF content was different between M, ranging from 364.45-467.43 g/kg DM. No differences (P>0.05) were observed in CP which averaged 62.08 g/kg DM. The TP, TT and CT content was different between M (P<0.05), the highest content was in YM with no effect observed in AC. B-gas production (mL of gas) presented differences between M and AC sampled (P<0.05). The gas production rate c on average was 0.042. Lag time was different between M (P<0.05). The <em>in vitro</em> digestibility of dry matter and organic matter were different between M (P<0.05). <strong>Implications</strong>: The results reported here serve as a tool for decision making on its possible inclusion as a forage addition to a diet in sheep feeding. <strong>Conclusions: </strong>The chemical composition and <em>in vitro </em>digestibility was different between M and the AC, contain secondary metabolites such as total phenols and condensed tannins and have an impact on <em>in vitro</em> fermentation.</p>