Enteric Methane Emissions and Rumen Fermentation Profile Treated by Dietary Chitosan: A Meta-Analysis of In Vitro Experiments

Abstract

Chitosan is a natural compound obtained from deacetylation of chitin, which is a biopolymer present in the exoskeleton of crustaceans such as crabs and shrimp. The present study aimed to perform a meta-analysis from published studies regarding the effects of chitosan on methane emission and rumen fermentation profile of in vitro batch culture experiments. A total of 41 studies from 12 articles were integrated into a database. Parameters included were gas production, methane emission, rumen fermentation characteristics, microbial population, nutrient digestibility, and fatty acid profile. Data were analyzed according to mixed model methodology in which different studies were treated as random effects and chitosan addition levels were treated as fixed effects. Results showed that chitosan addition was able to reduce enteric methane emissions (p<0.001). Such methane decrease was accompanied by a decline in the protozoa population (p<0.05) and a tendency of methanogen reduction (p<0.1). The increasing chitosan level was associated with a decrease in total VFA and ammonia concentrations (both at p<0.001). Chitosan addition decreased acetate proportion (p<0.001) while elevated propionate proportion (p<0.001). Chitosan was associated with an increase of dry matter digestibility, crude protein digestibility, and neutral detergent fiber digestibility (p<0.001). Chitosan increased concentrations of C 18:3n3 (p<0.05), conjugated linoleic acid (p<0.01) and polyunsaturated fatty acids (p<0.01) while decreased concentration of saturated fatty acids (p<0.001). It can be concluded that chitosan addition can mitigate enteric methane emission and alters rumen fermentation profiles in a favorable direction.

Effect of Chitosan and Naringin on Enteric Methane Emissions in Crossbred Heifers Fed Tropical Grass

“…As regards CHI, previous studies reported a reduction of gas production using chitin and chitosan and a decrease in the digestibilities of organic matter and dry matter of the ration; the latter was probably due to its antiprotozoal effect [40]. In a meta-analysis, in vitro gas production showed that an increase in the doses of chitosan was associated with a decrease in total gas production (p < 0.001), reduction of the protozoa population (p < 0.05), and an increase of the total microbial population (p < 0.01) [43].…”

Modulatory effects of dietary tannins on polyunsaturated fatty acid biohydrogenation in the rumen: A meta-analysis

“…There is also a toxic effect of tannins on rumen microbes in the terminal stage of BH, which has a positive impact on increasing the percentage of rumen intermediate fatty acids [56]. Similarly, a meta-analysis of 12 articles on natural rumen biomodifiers, for example chitosan, showed similar characteristics to tannin supplementation, such as reduced SFA, and increased rumen CLA and PUFA with in vitro batch culture [57].…”

In sacco nutrient degradability of silage containing intact and defatted black soldier fly (Hermetia illucens) larvae

“…The increase of nutrient digestibility of ruminants due to chitin and chitosan is seemed to be related to the change of microbial population structure in the rumen. The compounds decrease the population and activity of protozoa, and subsequently decrease predation of the fauna on rumen bacteria, and finally enhance the bacteria population for degrading substrates (Harahap et al, 2020). Further, the compounds may act like tannins that elevate protein utilisation in the digestive tracts of ruminants (Kondo et al, 2014;Jayanegara et al, 2019).…”