Effects of Ensiling Oxytropis glabra with Whole-Plant Corn at Different Proportions on Fermentation Quality, Alkaloid Swainsonine Content, and Lactic Acid Bacteria Populations.

Abstract

Simple SummaryIn Inner Mongolia, developing innovative forages is an indispensable way to ease the shortage of animal feed. Oxytropis glabra (OG) has become a dominant population, with a high nature yield in the degraded grassland of Inner Mongolia. As a typical legume, it is rich in amino acids and trace elements, so using OG to feed livestock is a valuable strategy. However, it contains swainsonine (SW), which hinders the utilization of OG. This study was conducted to evaluate silage fermentation and SW removal from OG ensiled with whole-plant corn at different proportions, and the result showed ensiling a mixture of OG and corn could be a valuable approach for producing livestock feed, as it had a positive effect on fermentation quality and SW detoxification; the optimal ratio was 1:1. In the silages, Lactobacillus plantarum was the most common microorganism present in all mixture silages, and Lactobacillus amylovorus and Lactobacillus brevis were prevalent at lower ratios of corn to OG. All representative strains were able to remove SW from OG fermentation, and the strains of L. amylovorus and L. plantarum had a higher SW removal rate. These mixtures of silages could make OG useable as a feed source in ruminant production.Oxytropis glabra (OG) is a leguminous forage that is potentially valuable for solving the shortage of feed for livestock production, while, in large quantities, it may be toxic because of its swainsonine (SW) content. In this study, OG was ensiled with whole-plant corn (Zea mays L.) at 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, and 0:10 ratios on a fresh matter basis, and, after 60 d of ensiling, the chemical composition, fermentation characteristic, SW removal rate, lactic acid bacteria (LAB) populations, and their capabilities for SW removal were analyzed. As the proportion of corn in the silage increased, the pH, as well as the propionic acid, ammonia-N, dry matter, crude protein, and SW contents, decreased linearly, while the lactic acid, neutral detergent fiber, and residual water-soluble carbohydrate contents increased linearly. Lactobacillus plantarum was the most common microorganism present in all mixture silages. Lactobacillus amylovorus and Lactobacillus brevis were prevalent at lower ratios of corn to OG. Meanwhile, the LAB strains belong to L. amylovorus and L. plantarum had a higher SW removal rate. Our results suggested that ensiling OG with whole-plant corn improves fermentation and decreases SW content, and that 5:5 is the optimal ratio, so this type of mixed silage could make OG useable for ruminant production.