Chemical composition and ruminal degradation kinetics of crude protein and amino acids, and intestinal digestibility of amino acids from tropical forages

Abstract

-The objective of this research was to determine the chemical composition and ruminal degradation of the crude protein (CP), total and individual amino acids of leaves from tropical forages: perennial soybean (Neonotonia wightii), cassava (Manihot esculenta), leucaena (Leucaena leucocephala) and ramie (Boehmeria nivea), and to estimate the intestinal digestibility of the rumen undegradable protein (RUDP) and individual amino acids of leaves from the tropical forages above cited, but including pigeon pea (Cajanus cajan). Three nonlactating Holstein cows were used to determine the in situ ruminal degradability of protein and amino acids from leaves (6, 18 and 48 hours of ruminal incubation). For determination of the intestinal digestibility of RUDP, the residue from ruminal incubation of the materials was used for 18 hours. A larger concentration of total amino acids for ramie and smaller for perennial soybean were observed; however, they were very similar in leucaena and cassava. Leucine was the essential amino acid of greater concentration, with the exception of cassava, which exhibited a leucine concentration 40.45% smaller. Ramie showed 14.35 and 22.31% more lysine and methionine, respectively. The intestinal digestibility of RUDP varied from 23.56; 47.87; 23.48; 25.69 and 10.86% for leucaena, perennial soybean, cassava, ramie and pigeon pea, respectively. The individual amino acids of tropical forage disappeared in different extensions in the rumen. For the correct evaluation of those forages, one should consider their composition of amino acids, degradations and intestinal digestibility, once the amino acid composition of the forage does not reflect the amino acid profiles that arrived in the small intestine. Differences between the degradation curves of CP and amino acids indicate that degradation of amino acids cannot be estimated through the degradation curve of CP, and that amino acids are not degraded in a similar degradation profile.

Effect of replacing alfalfa hay with a mixture of cassava foliage silage and sweet potato vine silage on ruminal and intestinal digestion in sheep

“…In addition, an earlier study showed that rumen undegradable N of cassava foliage had low intestinal digestibility (23.5%) in cattle (Miranda et al . ). The lower intestinal N digestion caused the decrease in total tract N digestibility when the CSP silage substitution in the diet was increased.…”

“…; Miranda et al . ). The supplementation of 20–30% CF in dietary DM as a major protein source in ruminant diets improved apparent DM digestibility and protein utilization and modified rumen fermentation, and consequently enhanced animal productivity (Hong et al .…”

Ovarian activity and estrus behavior in early postpartum cows grazing Leucaena leucocephala in the tropics

“…Plasma mimosine levels observed in the present study (1270-1530 μg/mL) were far higher than those reported by Ghosh et al (2007) in confined cows (25 and 71 μg/mL). This difference may be explained by the high rumen degradability of L. leucocephala (Miranda et al 2012), especially when ruminants are grazing and thus allowed to select their diet. This high degradability may also have caused an increase in Leucaena passage rate from the rumen, leading to decreased transformation of mimosine to its derivatives in the rumen (Puniya et al 1996).…”

Kinetics of digestion of low-quality forage grazed by beef cattle fed supplements containing increasing levels of rumen undegradable protein

“…The modern nutrition systems for ruminants use the amino acid supply from digested and absorbed true proteins in the small intestine (Miranda et al, 2012;Gao et al, 2015). Tropical grasses have high herbage production, but as the forage matures, the cell walls become thick and incrusted by lignin.…”