Chemical composition, fermentation characteristics, digestibility, and degradability of silages from two amaranth varieties (Kharkovskiy and Sem), corn, and an amaranth-corn combination.

Abstract

Amaranth ( sp.) is a C plant adapted to poor soils and regions with limited rainfall and high temperatures. The plant is characterized by a yield of up to 85 t/ha, CP concentration of up to 28.5% of DM, and DM digestibility of 59 to 79%, which may vary depending on the species and variety. The potential of this plant as a forage source for ruminants has not been completely considered. This study aimed at assessing the nutritive value of silages from corn (), 2 amaranth () varieties (var. Kharkovskiy and Sem), and an amaranth-corn combination by chemical composition, silage fermentation characteristics, in vivo digestibility, and in situ DM degradability. Treatments evaluated were ensiled corn var. hybrid SC 704 (EC), ensiled amaranth var. Kharkovskiy (EK), ensiled amaranth var. Sem (ES), ensiled corn-amaranth var. Kharkovskiy mixture, and ensiled corn-amaranth var. Sem mixture. Five sheep were used in a 5 × 5 Latin square design experiment to determine in vivo digestibility. The nylon bag technique was used to determine the in situ DM degradability using 3 ruminally fistulated sheep. Compared with EK, ES had greater ash-free NDF (NDFom) and CP concentrations. In comparison with EC, the ensiled amaranths and corn-amaranth mixtures had a greater ( < 0.001) concentration of CP but less concentrations of NDFom, ADL ( < 0.001), and water-soluble carbohydrates ( = 0.034). Silage pH and ammonia-N concentration were the least ( < 0.001) for EC and greatest for ES. The EC had greater ( < 0.001) concentrations of lactic and acetic acids but less ( < 0.001) concentrations of propionic and butyric acids compared with the other silages. The in vivo DM digestibility ( = 0.035) and ME ( = 0.030) of EK and ES were greater than those of EC. Effective degradability of DM in EK and ES was less ( < 0.001) than with the other silages. Overall, mixing amaranth with corn improved concentration of CP and digestibility of the mixed corn-amaranth silages and has the potential of completing corn in ruminant diets.