Study On Bacteriostasis Antivirus And Immunological Enhancement Of Aloe Extract

Aloe barbadensis Miller (Aloe vera) is a tropical or subtropical plant with turgid lace-shaped green leaves. Aloe vera is rich in bioactive components such as aloe polysaccharide, anthraquinone compound, amino acid and microelement which endow it with a variety of pharmacological activities. Like other plant polysaccharides, aloe polysaccharide has such functions as broad-spectrum immunoregulation, anti-radiation, anti-HIV, anti-ulcer, antioxidation and hypolipidemic and hypoglycemic effects. Chemical biosynthetic pharmaceutics (such as antibiotics) are overused, resulting in a sharp deterioration in meat quality and flavor. Research and development of new immunopotentiators is becoming the new focus of livestock husbandry research. Now the study on aloe polysaccharide mainly focuses on the development of human health products. The application of aloe polysaccharide to poultry industry as immunopotentiator is rarely reported. At home, some scholars have already proved that the addition of aloe polysaccharide to chicken feeds can increase immune organ index and phagocytic index, and promote average daily intake and average daily gain. In the light of relevant research of predecessors, our group have studied the effect of immunological enhancement of aloe polysaccharide on SPF chickens immunized with B. avium vaccine, which provides experimental evidence for the application of aloe polysaccharide as immunopotentiator. It consequently infuses vitality to the healthy development of poultry industry.This research consists of two parts as follows:Part One: Study on bacteriostasis and antivirus effects of aloe crude extractBacteriostasis to pathogenic bacteria of aloe crude extract was studied by using the drilled nutrient agar medium. Bacteriostasis of different concentrations of crude extracts to pathogenic bacteria was studied by using medium containing crude extracts. Proliferation of pathogenic bacteria in liquid medium containing different concentrations of crude extracts was studied by using bacterial count method. This test studied antivirus effect of crude extracts to IBDV and NDV using cell culture technique and embryo inoculation methods. The result showed that bacteriostasis to Staphylococcus aureus, Micrococcus tetragenus, Sarcina, Escherichia coli and Bacillus cereus was better than others with inhibitory zone diameter longer than 14mm. There were countable colonies in mediums with more than 40% of crude extracts. The time of reaching bacterial growth logarithmic phase was extended for more than 4h in the liquid medium containing more than 80% of crude extracts. OD570nm of the experimental groups were higher than virus control group. The HA results of experimental groups were lower than virus control group. With the increase of concentration and action time, HA results became lower.Part Two: Study on Extraction of Polysaccharides from Aloe and Immune Enhancement in ChickensAloe polysaccharide was extracted by the modified water extraction and alcohol precipitation method. 210 chicks (5 days old) were selected and randomly allocated into 6 groups. Aloe polysaccharides contents of Bordetella avium immunogen in groups I, II and III were 40mg/ml,20mg/ml and 10mg/ml, and Propolis content in group IV and pine pollen polysaccharide content in group V was 10mg/ml. Group VI contained no additives in its immunogen. Each chick in every group was injected with 1ml corresponding immunogen. The samples of blood, spleen, bile were then taken from the chicks 3, 7, 14, 21, 28, 35, 42 days after immunization. Serum antibody titer was determined by micro agglutination test, lymphocyte ratio by automated hematology analyzer, spleen lymphocyte transformation rate by flow cytometry, and antibody in bile by ELISA method. Results showed that the yield of aloe polysaccharides was 0.72% with the purity of 82.4%. The level of serum and bile antibody, lymphocyte ratio and spleen lymphocyte transformation rate in groups I, IV, and V were conspicuously higher than group VI (P<0.05). There was no conspicuous dIfference among groups of I, IV and V, the result of which were all conspicuously higher than group II and III (P<0.05).