| To study the effect of epidermal growth factor(EGF), glutamine(Gln) and porce growth relase factor gene plasmid (pGRF gene plasmid) on development of the intestinal mucosa and improving the growth of early weaned piglets, four experiments were carried out. In the first set of experiment, eight crossed pigs(Landrace Large White Taihu, initial weight:5. 96kg) from the same litter, weaned at 21 days of age, were randomly assigned to 2 equal groups of four pigs each. Pigs of 1 groups were administered 4. O g of EGF and the pigs of the other group administered the solution of saline (0.9%). All pigs were injected subcutaneously on yhe dorasl with 4. 0 g/kgBWday-1 EGF or the equivalent volume of water for the control every 1 day for five days. The dose was determined from the hypersensitive dose used in mice by the report of Christiane (1982), Charlotte (1993) and James (1987) .In experiment 2, twenty-five crossed pigs(DurocX Landrace Large White, initial weight:5. 96kg), weaned at 21 days of age, picked out from eight litters were divided randomly into five equal groups of five pigs of each. Pigs of the four groups were administered 1, 3, 6, 9 U g/kgBWday"1 or the equivalent volume of saline for the control subcutaneously on yhe dorasl every 1 day for five days, (the same to the experiment 1). In experiment 2, the course of experiment was divided into two phases including phase 1 and phase 2. In phase 1, nine piglets(initial weight:3. 76kg), weaned at 21 days, from the same litter was randomly assigned to three groups of three piglets each. l.(K 0. 5 0 g/kgBWday-1 EGF, three times every day for five days, were injected to all pics respectively. In phase 2, nine piglets(initial weight:4. 00ke). weanedat 21 days, from the same litter was randomly assigned to three groups of three piglets each. 1. 0 g/kgBWday-1 (three times every day for five days), 1.0 g/kgBWday-1 and 0. 5 g/kgBWday-1 (one time) EGF were injected to piglets from three groups respectively. The dosage range, sensitive level as well as injecting times were studied. The ADG, ADFI and F/G and the relationship with the effect were examined. In experiment 4, fourty-two piglets (Landrace Large White Taihu, initial weight:4. 51kg), weaned at 28 days, were picked out from five litters and alloted randomly to seven equalivent groups according to the combined ways of EGF, Gln and pGRF gene plasmid. 1. 0 g/kgBWday-1 EGF and 1. 0mg pGRF gene plasmid were injected to piglets from the groups including EGF, pGRF gene plasmid, EGF+Gln, EGF+pGRF gene plasmid and EGF+Gln+pGRF gene plasmid by subcutaneously and muscle in buttocks respectively, while the glutamine was added to the diet directly for Gln, EGF+Gln, EGF+Gln + pGRF gene plasmid. In fourty two days of age, three piglets from three replicates in groups of EGF, EGF+Gln, EGF+pGRF gene plasmid and EGF+Gln+pGRF gene plasmid were slaughted and samples were collected. The production performance, diarrhea, fair development, the change of structure and function in the small intestine, immune function and changes of some hormones and so on were studied. In experiment 4, the effect of relaxing stress on early weaned piglets when EGF was used only or EGF combined with Gln and pGRF gene plasmid was mainly examined. The result showed that the effect of the combined way for EGF, Gln and pGRF gene plasmid was much better than only use, which was more stand out in given diets (the low nutriention level, less level of dried whey and fish meal, no sprayed dried blood meal was added). Datas indicated the close relationship among these three substances from milk. The results showed that:1. When epidermal growth factor used only, the effect showed distinct dose dependent effect. The best level was 6. O g/kgBWday-1. In 1. 0 g/kgBWday-1 levels, the effect of EGF was close corrlated with its injected times.2. In this experimental diets , that is (the low nutriention level, less level of dried whey and fish meal, no sprayed dried blood meal was added) wasfed on piglets, the effect of EGF, Gln and pGRF gene plasmid (only use... |
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