A Study On Screening Of Compound Immunopotentiator Formula And Its Counteracting Effects To Immune Challenge

The study was conducted to screen of compound immunopotentiator formulas through lymphocyte transformation test in vitro and feeding trial in which growth performance, immune indices and antioxidant indices of plasma were determined, then to investigate the effects of this compound immunopotentiator on the levels of plasma hormones, inflammatory cytokines and immune indices in weaned piglets after Lipopolysaccharides challenge. The study was divided into four experiments:Exp 1 Study on screening of compound immunopotentiator formulas in vitroThe trial was an in vitro trial to screen of compound immunopotentiator formulas with better immunoenhancement. Four compound immunopotentiator formulas included Astragalus polysaccharides plus Acantbepanax senticosus saponin (APS+ASS), Astragalus polysaccharides plus Epimedium polysaccharides (APS+EPS), Astragalus polysaccharides plus Achyranthes bidentata polysaccharides plus Acantbepanax senticosus saponin (APS+ABPS+ASS) and Astragalus polysaccharides plus Achyranthes bidentata polysaccharides plus Epimedium polysaccharides (APS+ABPS+EPS). Each compound preparation was prepared with RPMI-1640 culture solution at five concentrations which were 50μg/mL, 100μg/mL, 200μg/mL, 400μg/mL and 800μg/mL, added in the peripheral blood lymphocyte of piglets in vitro, and cultured 72h. The peripheral blood lymphocyte proliferation was determined by MTT method. The results showed that: four compound formulas at suitable concentration stimulated the lymphocyte proliferation synergistically with ConA or LPS, the actions of APS plus ASS and APS plus ABPS plus ASS were better. Exp 2 Effects of compound immunopotentiators on growth performance, immune function and body antioxidant function in weaned pigletsThe trial was conducted to compare the application effects of compound A (APS plus ASS) and compound B (APS plus ABPS plus ASS) on the dietary in weaned piglets. This was a 14-d growth assay, in which 32 piglets (Yorkshire) of 31±3 days old with an average body weight of 9.29±0.53kg were randomly allotted into four dietary treatments, with four replicate pens per treatment and two piglets per pen. Dietary treatments included control group (basal diet without antibiotics), APS group (basal diet plus 0.05%APS), compound A group (basal diet plus 0.05%compound A immunopotentiator) and compound B group (basal diet plus 0.05%compound B immunopotentiator). At the end of the trial, blood samples from anterior vein were collected to determine the biochemical and immune indices of plasma. The results indicated that: compound A immunopotentiator promoted the average daily gain (ADG) (P<0.05) and decreased the ratio of feed to gain (F/G) significantly (P<0.05); increased the activity ofγ-glutamyltransfarase (GGT) and Nitric Oxide Synthase (NOS) (P<0.05); improved the level of Immunoglobulin G (IgG) of plasma (P<0.05) and decreased the content of MDA significantly (P<0.05).Exp 3 Effects of compound immunopotentiators on immune indices, the levels of plasma hormones and inflammatory cytokines, plasma biochemical indices in weaned pigletsThe trial was conducted to study the effects of compound A immunopotentiator on the immune indices, the levels of plasma hormones and inflammatory cytokines and biochemical indices in weaned piglets. This was a 27-d growth assay, in which 16 crossbred piglets (Duroc×Landrace×Yorkshire) of 23±3 days old with an average body weight of 6.51±0.19kg were randomly allotted to two dietary treatments, with four replicate pens per treatment and two piglets per pen. Dietary treatments included control group (basal diet without antibiotics) and compound A group (basal diet plus 0.05%compound A immunopotentiator). On day 14, blood samples from anterior vein were collected to determine the level of plasma hormones, inflammatory cytokines and lymphocyte transformation ratio etc. At the same time, all piglets were injected i.m. with bovine serum albumin (BSA), then the level of BSA antibody in serum was determined 7 days later. On day 21, piglets were injected Phytohemagglutinin (PHA) intradermally on the left inside flank of the pig about 5cm posterior to the last nipple and 5cm from the midiine for skin-test responses. The results showed that: compound A immunopotentiator improved the increment of skinfold thickness which was stimulated by PHA ( P<0.05); decreased the levels of somatostatin (SS) and Pancreas Glucagon (PG), the activity of lactate dehydrogenase (LDH) (P<0.05).Exp 4 Effects of compound immunopotentiator on the levels of plasma hormones, inflammatory cytokines and immune indices in weaned piglets after Lipopolysaccharides challengeThe trial was a 27-d growth assay, in which 16 crossbred piglets (Duroc×Landrace×Yorkshire) of 23±3 days old with an average body weight of 6.51±0.19kg were randomly allotted to two dietary treatments, with four replicate pens per treatment and two piglets per pen. Dietary treatments included control group (basal diet without antibiotics) and compound A group (basal diet plus 0.05%compound A immunopotentiator). On day 23, all piglets were injected intraperitoneally with 100μg/kg BW LPS, and blood samples were collected 3h after LPS challenge to determine the levels of plasma hormones, inflammatory cytokines and immune indices. As a result, compound A immunopotentiator decreased the levels of Interleukin-6 (IL-6) and insulin, stimulated the secretion of SS (P<0.05), improved the level of Interleukin-2 (IL-2) (P<0.10), but had no effect on growth performance of weaned piglets prechallenge and postchallenge (P>0.05).Above all, the results showed that: compound A immunopotentiator promoted the growth performance, improved the immune function and the counteracting effects to immune challenge.