Effect Of Dunaliella Salina Powder On The Rumen Fermentation And Milk Performance And Immune Function In Lactating Cows

This experiment was conducted to study the effects of Dunaliella Salina Powder (DSP) on in vitro rumen fermentation and milk performance and immune function of dairy cows, and to provide theoretical basis for addition of DSP in diet of dairy cows.The experiment was divided into 4 parts. The trail 1 was divided into 4 treatment groups with 3 replicates in each treatment in a completely randomized design, furthermore the control group without DSP and the other groups adding 4.5mg, 9mg, 18mg DSP based on the control group respectively. The culture system was 60ml in all groups and the ratio of concentrate to roughage was 45:55. The sample was collected at the time points of 2, 4, 8, 12, and 24h during in vitro culturationBased on trail 1, 18 healthy Holstein cows in mid lactation were selected accrodding to similar age, weight, lactation period, milk yield and physiological status, and these cows were randomly blocked into three groups (control group, 1.5 times of vitamin A group, DSP group) with 6 replicates in each treatment in trials 2, 3 and 4. The dairy cows were fed basal diet (110 IU/kgBW vitamin A) for control group, and were added 0.5 time of vitamin A (55IU/kgBW) based on the control group for 1.5 times of vitamin A group. DSP group was fed 9g/d Dunaliella Salina Powder based on the control group for each dairy cow. Pre-trial period was 15 d and the experimental period was 60 d. These trails were conducted to study the effects of DSP on milk performance, serum biochemical indexes, antioxidant capacity, immune function and the concentration of vitamin A andβ-carotene in milk and serum.The results showed that:1. The rumen fermentation parameters were affected by adding DSP. The supplementation of 9mg DSP in in vitro culture system reaulted in the decrease of NH3-N and increases of BCP and VFA concentrations , and the supplementation of 9mg DSP had the best effects on the rumen fermentation. The addition of 4.5mg and 18mg DSP had no significant effect on Rumen Fermentation in vitro.2. The supplementation of 9mg DSP could significantly increase the concentration of vitamin A in the incubating fluids, while the supplementation of 4.5mg and 18mg DSP had no significant effects. The concentration ofβ-carotene in the incubation fluids were significantly increased by addition of DSP. 3. The addition of DSP or 1.5 times of vitamin A in diet of the dairy cows could improve the milk performance and increase economic benefits. Moreover, DSP group was better than 1.5 times of vitamin A group .4. The content of urea nitrogen and MDA in serum were significantly decreased by the supplementation of DSP and 1.5 times of vitamin A in diet, and the level of T-AOC, SOD and GSH-Px of serum were also increased on certain degree.5. Compared with the control group, the DSP group could significantly decrease the milk somatic cell counts, and had a significantly increasing tendency of IgG antibody and IgM antibody of serum. The addition of the 1.5 times of vitamin A could significantly decrease the milk somatic cell counts, and the serum IgG antibody had a significantly increasing tendency.6. The concentration of vitamin A andβ-carotene in milk and serum were not affected obviously by the supplementation of DSP or 1.5 dose of vitamin A in diet. Compared with the control group, the Dunaliella Salina Powder group could greatly improve the increasing extent of vitamin A andβ-carotene(relative to the beginning of experiment) in milk.