Effect Of Different Energy Levels On Environment Within The Gastrointestinal Tract, Immune Perpormance And Expression Of IFN-γ And RLA-A3Gene In Rex Rabbits

The objective of the experiment was to study the effect of different energy levels onenvironment within the gastrointestinal tract, immune performance and expression of IFN-γand RLA-A3gene in rex rabbits. Single-factor completely random experiment design wasused with1601.5months of Rex rabbits were divided into4groups, each group40repeats.Four treatment groups were feeding digestible energy for9.7MJ/kg,10.5MJ/kg,11.3MJ/kg,12.1MJ/kg of four types of diet and other nutrients were the same. Pre-test period was7days,experiment period was2months. At the30th and60th day of the experiment,6rabbits wereslaughtered in each group to collecting samples to determine the gastrointestinal pH, immuneorgan index, serum IgG, intestinal IgA and the expression of IFN-γ and RLA-A3gene.1.5~2.5months of age: With the increase of energy levels, Rex’s immune organ indexare increased. The thymus index of Group Ⅰ differ from Ⅲ and Ⅳ (P <0.05); the spleenindex of group Ⅰ also differ from group Ⅳ (P <0.05). Serum IgG levels showed afluctuation, and group Ⅱ was significant different from group Ⅰ and Ⅲ (P <0.05), justlike the groupⅣ, the intestinal SIgA content was similar between groups (P>0.05). HepaticIFN-γ was increased along with the increase of energy levels, and group Ⅳ wassignificantly higher than group Ⅰ (P <0.05). Liver RLA-A3expression was elevated withthe energy levels increased, but the difference between the groups did not reach a significantlevel (P>0.05). Spleen IFN-γ expression was increased and then decreased from group Ⅰto Ⅳ, and group Ⅲ was highest, but the difference between groups were not significantly(P>0.05). Spleen RLA-A3expression was the same with Spleen IFN-γ. Gastric pHexhibited a slight decline trend and then increased with the increase of energy; cecal pH had adownward trend, especially the preceding cecum.2.5~3.5months: The immune organ index was increased with the increase of energylevels, thymus index of group Ⅱ was the highest and was similar between groups; spleenindex of group Ⅲ was higher than group Ⅰ (P <0.05).Immunoglobulin increased with theincrease of energy level and then decreased, and reached the maximum in the group Ⅲ. IgGof group Ⅲs erumwas significantly different from group Ⅰ(P <0.01); SIgA of group Ⅲ was significantly higher than group Ⅰ and group Ⅱ (P <0.05). Liver IFN–γ was increasedwith the increase of energy levels (P <0.05). Liver RLA-A3was similar from group Ⅰt oⅣ(P>0.05). Spleen IFN–γ and RLA-A3was reduced after rising first, and the highest wasgroup Ⅲ, but the expression between energy levels wassimilar (P>0.05). Gastric pH alongwith the change of energy level present a trend of fluctuations, and was increase a lotcompared with1.5~2.5months. Cecal pH with the increase of energy levels rise after fallingfirst, the trend was most obvious in the preceding cecum.Through this experiment, we can draw some conclusion:(1) The increase of energy levelcan increase the immune performance of rex;(2) The increase of energy level can reduce thececum pH, to promote the healthy growth of Rex;(3) Growth rex’s appropriate diet energylevel is11.3MJ/kg, and in the early stages of growth, diet energy level can also be a slightlyhigher.