The Role of Chitosan as a Possible Agent for Enteric Methane Mitigation in Ruminants

Abstract

Simple SummaryRuminant husbandry is one the largest contributors to greenhouse gas emissions from the agriculture sector, particularly of methane gas, which is a byproduct of the anaerobic fermentation of structural and non-structural carbohydrates in the rumen. Increasing the efficiency of production systems and decreasing its environmental burden is a global commitment, thus methane mitigation is a strategy in which to reach these goals by rechanneling metabolic hydrogen (H2) into volatile fatty acids (VFA) to reduce the loss of energy as methane in the rumen, which ranges from 2% (grain rations) to 12% (poor-quality forage rations) of gross energy intake. A strategy to achieve that goal may be through the manipulation of rumen fermentation with natural compounds such as chitosan. In this review, we describe the effects of chitosan on feed intake and rumen fermentation, and present some results on methanogenesis. The main compounds with antimethanogenic properties are the secondary metabolites, which are generally classified into five main groups: saponins, tannins, essential oils, organosulfurized compounds, and flavonoids. Novel compounds of interest include chitosan obtained by the deacetylation of chitin, with beneficial properties such as biocompatibility, biodegradability, non-toxicity, and chelation of metal ions. This compound has shown its potential to modify the rumen microbiome, improve nitrogen (N) metabolism, and mitigate enteric methane (CH4) under some circumstances. Further evaluations in vivo are necessary at different doses in ruminant species as well as the economic evaluation of its incorporation in practical rations.AbstractLivestock production is a main source of anthropogenic greenhouse gases (GHG). The main gases are CH4 with a global warming potential (GWP) 25 times and nitrous oxide (N2O) with a GWP 298 times, that of carbon dioxide (CO2) arising from enteric fermentation or from manure management, respectively. In fact, CH4 is the second most important GHG emitted globally. This current scenario has increased the concerns about global warming and encouraged the development of intensive research on different natural compounds to be used as feed additives in ruminant rations and modify the rumen ecosystem, fermentation pattern, and mitigate enteric CH4. The compounds most studied are the secondary metabolites of plants, which include a vast array of chemical substances like polyphenols and saponins that are present in plant tissues of different species, but the results are not consistent, and the extraction cost has constrained their utilization in practical animal feeding. Other new compounds of interest include polysaccharide biopolymers such as chitosan, mainly obtained as a marine co-product. As with other compounds, the effect of chitosan on the rumen microbial population depends on the source, purity, dose, process of extraction, and storage. In addition, it is important to identify compounds without adverse effects on rumen fermentation. The present review is aimed at providing in...

Chitosan and cottonseed processing method association on carcass traits and meat quality of feedlot lambs

“…Chitosan is known for its effect on ruminal fermentation, where it modifies the volatile fatty acid production patterns, improving the efficiency of energy utilization for growth and production [33]. However, in this study, slaughter weight was similar between the animals, suggesting that the chitosan dose supplied did not influence animal performance.…”

“…Chitosan is widely used as an antimicrobial agent and, as a result, it is also largely employed as an additive in the diet of dairy herds. Its use is supported by the fact that it is considered a modulator of ruminal fermentation [ 10 ]. Chitosan has also been described to possibly optimize feed efficiency by reducing ruminal methane and increasing propionic acid production [ 11 ], as well as by inhibiting ruminal biohydrogenation and increasing vaccenic acid ( t 11-C18:1) and total conjugated linoleic acid (CLA) in in vitro assays [ 12 ].…”

Ruminal Microbiome Manipulation to Improve Fermentation Efficiency in Ruminants

“…Chitosan is a natural polycationic polymer, nontoxic, biocompatible, biodegradable; thus, it is safe for human as well as animal consumption [61]. It is a linear polysaccharide composed of two repeated units-D-glucosamine and N-acetyl-D-glucosamine linked by β-(1-4)-linkages [61].…”

“…Chitosan is a natural polycationic polymer, nontoxic, biocompatible, biodegradable; thus, it is safe for human as well as animal consumption [61]. It is a linear polysaccharide composed of two repeated units-D-glucosamine and N-acetyl-D-glucosamine linked by β-(1-4)-linkages [61]. It can be found in the structural exoskeleton of insects, crustaceans, mollusks, cell walls of fungi, and certain algae, but it is mainly obtained from marine crustaceans [62].…”

Health concerns of lambs fed cottonseed hulls combined with chitosan by examining the blood metabolic profile and histopathology of the kidney, liver, and rumen

“…Since it has a broad antimicrobial spectrum, is anti-inflammatory, is an antioxidant and has digestive modulatory on the ruminal metabolism (Khambualai et al 2009;Goiri et al 2010), it may influence the biohydrogenation and increase the supply of unsaturated fatty acids and nutraceutical compounds (Goiri et al 2009a;Goiri et al 2009b;Goiri et al 2009c;Wencelova et al 2014). Another benefit of its utilisation is the increase in the proportion of propionate and a de-crease in the production of methane, which translates into greater energy efficiency in ruminants (Del Valle et al 2017;Jimenez-Ocampo et al 2019). However, its use as an additive in the ruminant diet is still poorly studied.…”