Effect of various additives on the chemical composition, fermentation parameters and apparent digestibility of Virginia fanpetals silage in sheep

The aim of this study was to determine the effect of various additives (straw, grass, molasses, dried sugar beet pulp – pellets, inoculant, organic acids) on the quality and fermentation profile of Virginia fanpetals (Sida hermaphrodita L.) silage. Silage samples were assayed for the content of dry matter – DM, crude ash, crude protein – CP, water soluble carbohydrates – WSC, neutral detergent fiber – NDF, acid detergent fiber – ADF and acid detergent lignin – ADL as well as pH and the concentrations of ammonia nitrogen, lactic acid, acetic acid and butyric acid. Silage quality was evaluated according to the DLG Key. Apparent digestibility was determined in sheep, and the digestibility coefficients of DM, CP, NDF, organic matter – OM and digestible OM were calculated. The tested additives increased DM, decreased ADL content (P≤0.01), and reduced WSC utilization (P≤0.05, P≤0.01) in silages. Only sugar beet pulp decreased the content of NDF and ADF (P≤0.01). All silages had similar pH values (4.01 - 4.10). The analyzed silages were characterized by intense lactic acid fermentation, which was inhibited only by the grass additive (P≤0.01). All additives suppressed acetic acid fermentation (P≤0.05, P≤0.01). Grass and sugar beet pulp significantly decreased the concentration of butyric acid (P≤0.01). The addition of grass decreased CP digestibility (from 92.1% in the control silage to 89.3%), whereas the addition of a bacterial inoculant (P≤0.01) and a blend of organic acids (P≤0.05) increased CP digestibility to 93.8% and 92.8%, respectively. The addition of grass and sugar beet pulp increased the coefficient of NDF digestibility by 6 percentage points relative to 60.9% in the control silage. The addition of the inoculant and organic acids decreased NDF digestibility to 56.0% and 50.5%, respectively. Dried sugar beet pulp was the most effective additive, which positively affected the chemical composition, fermentation profile and apparent digestibility of Sida silage.