Effects Of Chitosan On Production Of Milk And Immune Function In Dairy Cows

The present study was conducted to investigate the effect of chitosan on in vitro ruminal fermentation, production of milk and immuinity function in dairy cows.The study included 6 trials. The first experiment was conducted to study the degradability of chitosan in rumen of dairy cows at 0, 2, 4, 8, 12, 24, 36 and 72h by nylon bag technique.The second experiment was conducted to study the effects of different levels of chitosan(0.00, 0.02, 0.1, 0.5, 1 and 2 %,respectively) on in vitro ruminal fermentation. The experiment was a single factorial design . The trial 3 to 6 were conducted to study the effects of dietary chitosan on production of milk, immune function, anti-oxidation function,biochemical indication in serum and microbes in rectum of dairy cows.The experiment was a matched-pairs design.12 dairy cows which were similar in weight, milk yield and lactation stage were allotted into the control group and the chitosan group with six dairy cows in each group. Chitosan was supplemented 15g per head each day for the control without supplementation of chitosan for chitosan group. Pre-trial period was 15 d and the experimental period was 60 d.Under the present experimental conditions, the results showed as follows:(1) Degradation ratio of chitosan was very low in rumen, and it was only about 7.79% at 72h.(2) pH value and concentrations of NH3-N and BCP and VFA and gas production in in vitro ruminal fluid were not affected obviously by chitosan supplementation.(3) Milk yield of cows fed the diet supplemented with 0.1% chitosan was increased remarkably and production of milk was increased 14.85% during the last 10 days of the experimental period compared with the control.(4) The addition of 0.1% chitosan in diet resulted in an increase in T-SOD and T-AOC activities of serum and anti-oxidation function was improved, and SCC in milk was obviously decreased.(5) The addition of 0.1% chitosan decreased concentration of calcium and increased phosphorous content in serum, and had little effect on the concentrations of BUN, TG, TC and activity of AKP in serum .(6) The addition of 0.1% chitosan in diet improved bacillus acidi lactici population and reduced Escherichia coli growth in rectum of dairy cows .