Effects of packing density and inoculation with lactic acid-producing bacteria to evaluate the potential for North American elderberry (Sambucus canadensis) fodder as silage

Authors: Nieman, Christine; CONWAY-ANDERSON, ASHLEY - University Of Missouri

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2022
Publication Date: 12/18/2022
Citation: Nieman, C.C., Conway-Anderson, A.C. 2022. Effects of packing density and inoculation with lactic acid-producing bacteria to evaluate the potential for North American elderberry (Sambucus canadensis) fodder as silage. Agronomy. 12:3212. https://doi.org/10.3390/agronomy12123212.
DOI: https://doi.org/10.3390/agronomy12123212

Interpretive Summary: Elderberry (genus Sambucus) refers to 10 species of shrubs and small trees from the family Adoxaceae found natively in temperate and sub-tropical regions around the world. Fruit from elder trees have a long history of medicinal and nutritional uses in many cultures, and commercial production in the United States is growing in popularity due to the health benefits from secondary plant compounds. Commercial elderberry production typically requires aggressive pruning in late fall to maintain productive canes the following year. Instead of pruning, integrated farms could graze the standing residue, however the effect of grazing on subsequent berry production is unknown. Thus, a potential solution may be to ensile the late-season biomass. A laboratory silo experiment was conducted to describe the nutritional characteristics of elderberry residue and to investigate two factors that influence silage quality: packing density and the use of an inoculant (lactic acid producing bacteria (LAB)). Sixteen laboratory PVC silos were constructed (10.2 cm diameter x 29.2 cm height) and chopped elderberry material was passed through a mesh screen (5.1 cm x 7.6 cm). Silage inoculant mixed at a rate of 0.5 g/L to provide inoculant at a rate of 4.4 mL/kg of material. Non-inoculated silage was sprayed with water at the same rate to provide equivalent levels of moisture between treatments. Laboratory silos were opened after 60 days of ensiling. Pre-ensiled elderberry fodder averaged 5.6% crude protein, 62.5% acid detergent fiber, 72.5% neutral detergent fiber, 11.4% non-fiber carbohydrates, and 53% total digestive nutrients, 52% relative feed value (RFV). Packing density did not affect any nutrient characteristics of the ensiled fodder. Acid detergent fiber was greater in un-inoculated silage, resulting in greater RFV for inoculated silage. Only lactic acid concentration was affected by packing density with greater concentrations in high-density silos. Inoculant affected several fermentation parameters with greater concentrations of acetic acid, while un-inoculated silages had greater concentrations lactic acid, however there were no differences in the amount of total acids produced. Overall, late-season elderberry fodder was successfully ensiled, but nutritive value was low. The nutrient and fermentation profile suggest that it could be incorporated into a maintenance diet in ruminants, potentially providing a winter feed resource.

Technical Abstract: Commercial elderberry production requires complete pruning in late fall to maintain productive canes. For integrated farms (livestock and crops), this biomass has potential as ensiled fodder for ruminant livestock. The objectives of this study were to determine the forage nutritive value of late-season (November) pruned elderberry (Sambucus canadensis L. “Rogersville”) fodder when ensiled. A 2 x 2 factorial laboratory silo experiment was conducted testing two packing densities with or without inoculation with lactic acid-producing bacteria silage inoculant to determine effects on silage nutritive values and fermentation parameters. Pre-ensiled elderberry fodder, composited from plants over 2000 m2, averaged 5.6% crude protein, 62.5% acid detergent fiber (ADF), 72.5% neutral detergent fiber, 11.4% non-fiber carbohydrates, 53% total digestive nutrients, and 52% relative feed value (RFV). The two packing densities were 160.2 kg dry matter/m3 and 240.3 kg dry matter/m3. Packing density did not affect any nutrient characteristics of the ensiled fodder. Acid detergent fiber was greater (p = 0.01) in un-inoculated silage, resulting in lower (p < 0.01) RFV for un-inoculated silage. Only lactic acid concentration was affected by packing density with greater concentrations (p = 0.04) in high-density silos. Inoculant affected several fermentation parameters with greater concentrations of (p < 0.01) propanediol, (p = 0.01) propanol, and (p < 0.01) acetic acid, while un-inoculated silages had greater concentrations of (p = 0.03) ammonia-nitrogen, (p < 0.01) lactic acid, (p = 0.02) succinic acid, and (p < 0.01) ethanol. Overall, late-season elderberry fodder was successfully ensiled, but nutritive value was low. Packing density did not affect nutritive value but did increase lactic acid concentration. Inoculation improved the RFV by reducing ADF, and though acetic acid production was greater in inoculated silage, total acid concentration was not affected.