Efeito do extrato da malva branca (Sida galheirensis Ulbr) sobre a cinética de produção de gás in vitro

Abstract

Caatinga is an exclusive Brazilian biome and has a great diversity of plants that can be used in animal feeding. A large part of these plant species is characterized by presenting different types of secondary compounds, which can be exploited as natural additives to be used in the feeding of ruminants, either when supplied through the direct consumption of forage plants or supplied as an extract. Thus, our objective of this study was to evaluate the effect of Sida galheirensis Ulbr extract on the gas production kinetics and the degradability of nutrients in vitro. The experimental design adopted was randomized blocks, with three levels of extract inclusion [0, 6 and 12% of dry matter (DM)], and four repetitions, with the blocks represented by three tests. Were determined: the phytochemical profile of S. galheirensis, the estimation of the gas production kinetics parameters, the ruminal parameters, and the degradability of dry matter, organic matter,

and crude protein. The gas production potential from total carbohydrates (Vt) and non- fibrous carbohydrates (Vf1) increased with the inclusion of Sida galheirensis extract.

However, gas production from fermentation of fibrous carbohydrates (Vf2) and gas production rates did not differ (P > 0.05) between treatments. The lag time or lag phase (L) was reduced (P < 0.0001) with the inclusion of the extract. The pH of the incubation medium decreased with increasing levels of S. galheirensis extract (P < 0.0001). The concentration of rumen ammoniacal nitrogen (NAR) did not differ between treatments (P = 0.4995), with an average value of 42.73 mg/dL. Dry matter (DMD), organic matter (OMD) and crude protein (CPD) degradability were significantly higher in the control diet compared to extract levels of 6 and 12%. The addition of 6% S. galheirensis extract was enough to modulate rumen fermentation, increasing gas production, and reducing nutrient degradability.