| In this study, intrauterine growth retardation(IUGR)post-weaned piglets were selected as the model to find out the impact of IUGR on the development of tissue growth and intestinal mucosal immunity function of small intestine, and soybean lecithin was used to regulate the development of tissue growth and intestinal mucosal immunity function of small intestine in IUGR post-weaned piglets. The object of the study was to supply a laboratory basis for the exploitation of soybean lecithin in swine production.Experiment I was designed to evaluate the effects of soybean lecithin on the performance and the development of tissue growth of small intestine.32IUGR piglets and16normal piglets were selected from the closely parity sows, deliveried at114±1d, male and female in half. In addition, the piglets selected as IUGR had a birth weight2standard deviations (SD) below the mean birth weight previously recorded in the same piggery. After weaned at21d, the normal piglets were assigned to the normal group (NC group), IUGR piglets were randomly divided into2groups, fed the basic diet and basal diet added1.5%soybean lecithin (IC group and IL group), with4replicates of4piglets in the groups respectively.The nutrient levels of the basal diet satisfied to NRC (1998) nutritional standards. One of the piglets was selected from every replicate randomly and slaughtered for sample collection at28d,66d and160d. The results indicated that:(1) Dietary soybean lecithin supplement significantly improved the performance of IUGR piglets in Group IL at28,66and160d. The body weight (BW) was significantly higher than that in Group IC(P <0.05), but at the28,66d the BW of Group IL was still significantly lower than that in Group NC (P<0.05) until160d. From the whole look (21d-160d),the average daily gain (ADG), average daily feed intake (ADFI) in Group IL were significantly higher than those in Group IC (P<0.05) and feed conversion rate (FCR) was significantly lower than that in group IC (P<0.05), but no significantly differences were observed between Group IL and NC.(2) The absolute weight of the small intestine, small intestinal mucosa and non-mucosa in Group IL were significantly higher than these in Group IC (P<0.05) at66d and160d, as well as the weight of per unit length, but the absolute weight of small intestine and intestinal non-mucosal at28d and66were still significantly lower than those in Group NC (P<0.05). There were no significantly differences among three groups on the absolute length of the small intestine, but in the Group IL and NC, the relative length of the small intestine at the day28and66were significantly lower than that in group IC (P<0.05).(3) There were no significantly differences between Group NC and IC on the jejunal mucosal lactase activity, as well as Group IL (P>0.05),but Goup IL was significantly higher that in Group IC at28d(/><0.05); The activity of jeujual mucosal sucrase in Group IL and NC were significantly higher than that in Group IC (P>0.05), and there was no significantly difference was observed between Group IL and NC at66d (P>0.05); The jejunal mucosal maltase activity have no significantly differences between Group IL and NC at66d and160d, but both of them significantly higher than that in the Group IC at66d.(4)The activity of amylase in different part of small intestine in Group IL was significantly higher than that in Group IC at66d,but no significantly difference was observed between Groups IL and NC; The activity of duodenal lipase in Group IL was significantly higher than that in Group IC, but no significantly differences between Groups IL and NC at66d and160d as well as the activity of ileal lipase at160d; The activity of total protease in all parts of small intestine has no significantly differences between Group IL and Group IC at28d and66d, but at160d, the activity of total protease in all parts of small intestine in Group IL was significantly higher than that in Group IC but no significantly difference compared with Group NC.Experiment Ⅱ, on the groundwork of the first experiment, we objected the effect of soybean lecithin on the morphology and mucosal immunity function of small intestine in post-weaned IUGR piglets. The results showed that:(1) The height and width of duodenal villus in Group IL were significantly higher than that in Group IC at66and160d, as well as the ratio of duodenal VL:VW and V:C at160d, but there was no significantly differences on the morphology between Groups IL and NC except the the mucosal thickness of duodenal at28d; The width of jejunal mucosa in Group IL was significantly higher than that in Group IC at28d,66d and160d, and there were significantly differences between Groups IL and IC on the jejunal villus height and width, the ratio of VL:VW and V;C, but no significantly differences on the morphology of the jejunum were observed between Group IL and IC at whole stages; The width of ileal mucosa and the height of ileal villus in Group IL were significantly higher than that in Group IC, but no significantly differences between Groups IL and NC.(2) After weaned at21d, the numbers of small intestinal IEL and GC in the three groups were gradually increased with age, but the number of duodeal and jejunal IEL in Group IL were significantly higher than that in the Group IC and no significant difference on the number of ileal IEL was observed amomg three group at whole stages; Compare with Group IC, the soybean lecithin not only significantly increased the number of duodenal and jejunal GC at66, but also significantly improved the duodenal and ileal GC at160d.(3)The level of jejunal mucosal IL-2at160d and IL-10at66d in Group IL were significantly higher than those in Group IC, as well as the level of jejunal mucosal SIgA at whole stage.The results indiated that:after weaned, with1.5%soybean lecithin supplemented significantly improved not only the performance and the the development of tissue growth and morphology and mucosal disaccharide, digestive enzyme activity of small intestine, but also the mucosal immunity function and the performance in post-weaned IUGR piglets. |
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