Effects of Chitosan on Rumen Fermentation Characteristics:An in Vitro Study Using Rusitec System

This experiment was conducted to study the effects of chitosan on in vitro rumen fermentation characteristics using Rusitec system.The fermentation system consisted of 400 mL rumen fluid,400 mL buffer,70 g rumen content and 10 g diet(concentrate∶ roughage=40∶ 60).Fermenters were divided into four treatments by a single-factor completely randomized design,and chitosan supplemental levels of the four treatments were 0(control group),500,1 000 and 1 500 mg,respectively.Two fermenters were used for each chitosan supplemental level,and the experiment consisted of two repeated trials,i.e.,and there were four replicates in each treatment and one fermenter per replicate.After a 7-day pre-trial period,fermentation parameters including methane yield,gas production,volatile fatty acid concentration and nutrient degradation rates were determined in a 2-day trial period.The results showed as follows: 1) compared with control group,methane yield in 500,1 000 and 1 500 mg groups was significantly decreased by 17.71%,31.67% and 50.37%,respectively(P0.05).2) The supplementation of chitosan significantly decreased the concentrations of acetic acid and butyric acid,and acetic acid to acrylic acid ratio(P0.05),but significantly increased propionic acid concentration(P0.05);the supplementation of chitosan significantly decreased the concentrations of total nitrogen,ammonia nitrogen and urea nitrogen(P0.05),but significantly increased microbe nitrogen concentration(P0.05).3) Compared with control group,crude protein degradation rate in 1 000 and 1 500 mg groups was significantly decreased(P0.05).4) Methane yield,the concentrations of total nitrogen,ammonia nitrogen,urea nitrogen,microbe nitrogen,acetic acid,propionic acid and butyric acid,acetic acid to propionic acid ratio,and crude protein degradation rate were significantly linearly correlated with chitosan supplemental level(P0.05).In conclusion,chitosan can modify rumen microorganism fermentation pattern,improve propionic acid concentration in fermentation fluid,reduce acetic acid concentration and methane yield,improve energy utilization,and abate degradation of protein in rumen.