Degradability, in vitro fermentation parameters, and kinetic degradation of diets with increasing levels of forage and chitosan

Abstract

Chitosan is the second most important natural biopolymer in the world, extracted from crustaceans, shrimps, and crabs; and can modulate rumen fermentation. Our hypothesis is that the addition of chitosan alters the fermentation patterns of different diets for ruminants. This study aimed to evaluate the effects of different levels of chitosan and forage on in vitro dry degradation kinetics and fermentation in a gas production system. The chitosan levels (0, 1625, 3500 or 7500 mg/kg of DM) were arranged in a completely randomized block design, and for in vitro ruminal fermentation assay we used a split splot arrangement. Into the incubator, all chitosan levels were distributed in the four jars, and the forage levels varying on 100, 65, 50, 35 and 20 on DM basis. Chitosan and roughage levels interaction effect (P≤0.05) on IVDMD; IVOMD. IVDCP and IVDNDF. Chitosan negatively affected IVDMD in all roughage levels evaluated. The pH and ammonia concentration present effect only for roughage levels and incubation hours. The chitosan didn’t change (P=0.3631) the total short-chain fatty acid concentration (overall mean = 21.19 mmol/L) and the C2:C3 ratio (overall mean = 5.85). The IVDCP showed the same decreasing quadratic behavior (P<0.0001). The increasing chitosan addition increases (P<0.0001) the gas production and decreases the (P<0.0001) the lag time (parameter C) of diets with greater concentrate participation, characterizing greater efficiency in the degradability of the diet, confirming its potential use in diets for ruminants. Chitosan changes in vitro dry degradation kinetics and fermentation at the minimum dose of 1722 mg/kg DM for all diets. The roughage level influenced the in vitro nutrients degradability and cumulative gas production.

In vitro and in sacco evaluation of total mixed ration silage added different levels of chitosan

“…Supplementation of 1-1.5% chitosan reduces actual DMD while increasing actual OMD and CPD. This result is in accordance with the studies by Wencelova et al (2014), Harahap et al (2020), andJacauna et al (2021) that the addition of chitosan to the diet decreases actual DMD and increases actual OMD and CPD. Because of the chitosan addition, the actual DMD in SE treatment decreased, which showed that SE treatments utilize slowly degrading materials as an energy and protein source in the rumen.…”

“…Without impairing the feed digestion, chitosan shifts fermentation to a more energy-efficient pathway (Seankamsorn et al 2019). In contrast, some studies have found that chitosan significantly decreased IVDMD (Jacauna et al 2021;Wencelova et al 2014). Additionally, Goiri et al (2009) hypothesized that the composition of the basic diet, particularly the proportion of forage to concentrate, may have a significant impact on the efficacy of chitosan.…”

“…This is most likely related to a mechanism of protection from ruminal degradation; under rumen pH conditions, the positively charged -NH 2 + groups of chitosan could potentially interact electrostatically with the negatively charged carboxyl groups in amino acids, potentially leading to NH 3 reduction (Harahap et al 2020). A decrease in the level of NH 3 is either an enhancement in microbial protein synthesis or a decrease in amino acid breakdown due to the microbial characteristics of chitosan (Jacauna et al 2021).…”