| Two experiments were carried out to study the effects ofα-ketoglutarate on intestinal function and growth performance in weaned Piglets. In the experiment 1, 32 crossed piglets ( Duroc×Landrace×Yorkshire, initial weight 8.57±0.46kg) , weaned at 28±2 days of age, were randomly allocated to 4 dietary treatments, each treatment 4 replicates, each replicate 2 piglets ( all female). Four experimental diets were basal diet supplemented with 0%, 0.5%, 1.0% and 2.0% AKG respectively. The experimental period was 14 days. Feed intake was measured each day. Diarrhea incidence was recorded daily. Average daily gain ( ADG) , average daily feed intake ( ADFI) , the ratio of feed to gain ( F/G) and diarrhea incidence frequency were calculated weekly. On day 14 post-weaning, all pigs were weighed and infused 10% D-xylose solution, after 60 minutes, blood samples were collected. The concentrations of MDA, D-Xylose, NO and Gln in plasma, the activities of SOD, DAO, NOS and iNOS in plasma, the growth performance and diarrhea incidence were studied. In the experiment 2, 12 crossed pigs (Duroc×Landrace×Yorkshire, initial weight: 5.79±0.75 kg), weaned at 21±2 days of age, were randomly allocated to 2 treatments, each treatment 6 replicates, each replicate 2 piglets( all female) . Piglets per treatment were respectively fed one of the experimental diets supplemented with 1.0%AKG and 1.0% Dextrose. The experimental period is 14 days. On day 14, all pigs were weighed and sacrificed. A midline laparotomy was performed. The abdomen was incised, and the small intestine was removed. The small intestine was cut into three 5cm segments at distal duodenum, mid-jejunum and mid-ileum. The segments were processed, embedded, and stained to make tissue sections, the villus height( VH) and the associated crypt depth( CD) , the villus width( WD) were measured, and then the ratio of villus height to crypt depth( VH/CD) and villous surface area( VSA) were calculated.Exp.1 Effects of AKG on the growth performance and blood biochemical parameters, intestinal function of weaned piglets( 1) Effects of AKG on the growth performance of weaned piglets 1.0% AKG group showed a tendency to have a higher ADG( P=0.103), ADFI( P= 0.164) and feed efficiency( P= 0.237), respectively, than the control group, 0.5% AKG group and 2.0% AKG group.( 2) Effects of AKG on blood biochemical parameters in weaned pigletsOn day 14, compared with the control group, GLB concentration of 0.5% AKG group was significantly increased ( P <0.05). Compared with 0.5% AKG group, CK activities of 2.0% AKG group was significantly decreased( P <0.05) .( 3) Effects of AKG on the concentrations of D-Xylose and endotoxin content and the activities of diamine oxidase in plasmaOn day 14, compared with the control group, D-Xylose concentration of 1% AKG was significantly increased ( P <0.01) . With the increasing levels of AKG, endotoxin content in plasma was decreased ( linear, P <0.01) .( 4) Effects of AKG on body antioxidative ability, the concentration of NO and glutamine, the activities of NOS and iNOS in plasma of weaned pigletsOn day 14, with the increasing levels of AKG, SOD activities in plasma were increased ( linear, P <0.05) . NO concentration in plasma was increased ( linear, P<0.1) and cNOS activities in plasma were increased ( linear, P<0.05) . AKG had no effect on iNOS activities in plasma of weaned piglets( P>0.05) .All the results above implied that exogenous AKG might play an important role in maintaining intestinal modality, improve the active absorption function of intestine and improve the ability of anti-oxidation injury in organism. The group of 1% AKG is the better. Exp.2 Effects of AKG on intestinal mucosal morphology and function in weaned piglets(1) On day 14, compared with the control group, the supplementation of 1% AKG decreased small intestinal crypt depth( P<0.05) and increased small intestinal crypt depth and VH/CD ( P<0.05) .( 2 ) D-xylose concentration of 1% AKG group was significantly increased on day 7 ( P<0.05) and tended to be increased on day 14.(3) On day 14, DAO activities of 1% AKG group were significantly decreased ( P<0.05) . In conclusion, this experiment indicated that the group of 1% AKG could promoted small intestinal mucosal repair and improve the barrier function and the active absorption function of intestines.According to the results of our study, We could obtain the following conclusions:to some extent,1.0%AKG can promote growth performance on piglets and improve histological morphology of the small intestine. In addition, 1.0%AKG could protect small intestinal mucosa barrier and enhance its absorbing capacity and the ability of antioxidation.
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