纳米载铜蒙脱石对断奶仔猪生长、消化性能及二糖酶活性的影响

取128头健康"杜长大"三元杂交断奶仔猪,随机分为4组,每组32头。分别饲喂基础日粮(对照组)、基础日粮+3.0g/kg纳米蒙脱石(MMT)、基础日粮+3.0g/kg纳米载铜蒙脱石(MMT-Cu)及基础日粮+117mg/kgCu2+。比较研究MMT-Cu对断奶仔猪生长、消化和肠黏膜二糖酶活性的影响。结果表明:饲料中添加3.0g/kgMMT-Cu,能显著(P<0.05)提高断奶仔猪的平均日增重和饲料转化效率;显著提高饲料干物质(P<0.05)、粗蛋白(P<0.05)、粗脂肪(P<0.05)的表观消化率和十二指肠内容物中总蛋白水解酶(P<0.05)、脂肪酶(P<0.05)、淀粉酶(P<0.05)的活性。与对照组相比,添加MMT组十二指肠内容物中脂肪酶、淀粉酶活性升高显著(P<0.05)。二糖酶活性研究表明,添加3.0g/kgMMT-Cu组仔猪空肠黏膜麦芽糖酶、蔗糖酶和乳糖酶活性均显著高于(P<0.05)对照组和CuSO4组。     

Effect of weaning, week postweaning and diet composition on pancreatic and small intestinal luminal lipase response in young swine

The effects of weaning, week postweaning and diet composition on concentration of lipase in the pancreas and small intestinal lumen were investigated in weanling swine. In Exp. 1, lipase levels were evaluated in suckling pigs from 2 to 35 d of age and in pigs weaned at 21 or 35 d of age. Pigs weaned at 21 d of age were fed a corn-soybean meal diet with lipase levels measured from 3 to 28 d postweaning. Pancreas weights increased during the suckling period; they were lowered at 3 d postweaning and were lower at 7 d postweaning than in suckling pigs but increased linearly from 3 to 28 d postweaning. Lipase level per unit wet tissue and total pancreatic levels increased from 2 to 35 d of age in suckling pigs (P less than .01). Weaning at 21 d of age resulted in a decline (P less than .05) in lipase levels in the pancreas at 3 and 7 d postweaning, but the levels subsequently tended to increase between 7 and 28 d postweaning. Whereas relative lipase levels in the intestinal lumen increased from 2 to 35 d of age in suckling pigs, total luminal enzyme did not decline upon weaning when pigs were weaned at either 21 or 35 d of age. Total luminal lipase per unit empty body increased linearly (P less than .01) each week postweaning. In Exp. 2, a 2 X 2 factorial arrangement of corn oil (0 or 6%) and dried whey (0 or 25%) was used to evaluate digestive lipase levels in pigs weaned at 21 d of age.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of beta-glucanase and xylanase supplementation on gastrointestinal digestive enzyme activities of weaned piglets fed a barley-based diet

The effects of supplementing a barley-based diet for weaned piglets withexogenous beta-glucanase and xylanase on gastrointestinal digestiveenzyme activities were investigated. Thirty-six cross-bred weaned pigletswere randomly assigned to two groups with three pens based on sexand mass. Each group was fed on the diet based on barley with or withoutadded beta-glucanase and xylanase (0.15%) for a 4-week period. Theresults showed that enzyme supplementation improved growth performanceof piglets significantly (p < 0.05), but had no effect (p = 0.091)on average daily feed intake. The results also showed that supplementationof beta-glucanase and xylanase had no effect on pepsin activity in gastriccontents but slightly decreased (p = 0.092) the pepsin activity ingastric mucosa. Meanwhile, no effect of enzyme supplementation ontrypsin activity in duodenal contents was observed. However, the activitiesof amylase and lipase in duodenal contents were significantly(p < 0.05) decreased, whereas the activities of maltase, sucrase andgamma-glutamyl transpeptidase (gamma-GT) in jejunal and ileal mucosa wereenhanced significantly (p < 0.05). The improvement of disaccharidaseand gamma-GT activity may be attributed to the positive impacts of exogenousenzymes on digestion and absorption of the nutrients. In conclusion,the current results indicated that supplementation with enzymes in barley-based diets could improve the growth performance of piglets,decrease the activities of amylase and lipase in duodenal contents andincrease the activities of disaccharidase and gamma-GT in jejunal and ilealmucosa.     

Immunolocalization of epidermal growth factor (EGF) and EGF receptors in the porcine upper gastrointestinal tract.

The factors controlling growth and maturation in the porcine gastrointestinal tract are not well understood. Epidermal growth factor (EGF) is a polypeptide that has been implicated in the control of gastrointestinal tract growth, maturation, and protection in other species. Immunoreactive EGF (IR-EGF) and EGF receptors (EGF-R) were histochemically identified in formalin-fixed tissues of the upper digestive tract of 1-, 3-, 7-, 14-, 21-, and 28-day-old pigs. The ductal epithelium consistently contained IR-EGF in the parotid salivary gland of pigs of all ages and in the mandibular salivary gland in pigs greater than or equal to 7 days old. Immunoreactive EGF was detected in the mucosal epithelium of the esophagus and nonglandular portion of the stomach, and in the pancreas and liver in all pigs. Gastric gland IR-EGF was inconsistently detected in pigs less than 14 days old and was consistently observed in all older pigs. Enterocyte EGF immunoreactivity was usually weak and was variably detected in the duodenum of pigs less than or equal to 7 days old and in the jejunum of pigs less than or equal to 14 days old, but was consistently observed in older pigs. Ileal immunoreactivity was erratic. Immunoreactive EGF-R were identified in the esophageal epithelium of all pigs, and in the nonglandular gastric and glandular gastric mucosa of all pigs, except for two 7-day-old pigs and one 7-day-old pig, respectively. Immunoreactive EGF-R were detected in the duodenal, jejunal, and ileal enterocytes of pigs of all ages examined.     

Influence of creep feeding and weaning on brush border enzyme activities in the piglet small intestine

The activities of the enterocyte brush border enzymes lactase (beta-D galactoside galactohydrolase, EC 3.2.1.23) and sucrase (sucrose alpha-D glucohydrolase, EC 3.2.1.48) were measured at set percentage lengths along the small intestines of 112 piglets killed between 21 and 32 days of age. The influences on these activities of consumption of creep feed and of weaning were recorded. Weaning at three weeks old resulted in large, rapid reductions in lactase activity at most sites along the small intestine; sucrase activity declined temporarily and then recovered. Minimum values were recorded about four to five days after weaning. Similar changes were observed whether or not creep feed was consumed before weaning. Continued consumption of creep feed by unweaned pigs over the 21 to 32 day period also produced small but significant reductions in lactase activities. The large loss of digestive enzyme activities at brush borders in weaned animals coincided with a reduced ability to absorb xylose and to checks in growth rate in otherwise healthy piglets.     

抗菌肽对发酵床饲养仔猪生长性能、消化酶及垫料理化性质的影响

试验旨在研究发酵床饲养模式下饲粮中添加抗菌肽对仔猪生长性能、胰腺和小肠内容物消化酶及小肠黏膜二糖酶和垫料蛋白酶、脲酶、铵态氮的影响。选用108头35日龄、体重13kg左右的健康苏钟猪随机分为3组,每组3重复,每重复12头,分别饲喂基础饲粮（对照组）、基础饲粮＋40mg/kg杆菌肽锌＋20mg/kg硫酸黏杆菌素（抗生素组）和基础饲粮＋300mg/kg抗菌肽（抗菌肽组）的试验日粮,试验期49d10结果表明：（1）各组间仔猪生长性能差异不显著（P〉0.05）。（2）与对照组相比,饲粮中添加抗菌肽能够显著提高仔猪胰腺、十二指肠和空肠内容物淀粉酶及空肠内容物胰蛋白酶活性（P〈0.05）;并显著提高仔猪十二指肠黏膜麦芽糖酶和空肠黏膜蔗糖酶、乳糖酶及回肠黏膜蔗糖酶活性（P〈0.05）;抗菌肽组十二指肠黏膜麦芽糖酶活性比抗生素组提高（P〈0.05）。（3）各组间发酵床垫料蛋白酶和脲酶活性及铵态氮含量差异不显著（P〉0.05）。综上所述,本试验条件下,饲粮添加300mg/kg的抗菌肽能够在一定程度上提高仔猪生长性能;提高胰腺、小肠内容物及小肠黏膜消化酶活性;同时不影响垫料蛋白酶、脲酶活性和垫料铵态氮含量。     

Oral administration recombinant porcine epidermal growth factor enhances the jejunal digestive enzyme genes expression and activity of early-weaned piglets

This study attempted to determine ingested porcine epidermal growth factor (pEGF) on the gastrointestinal tract development of early-weaned piglets. Thirty-two piglets (14-day weaned) were randomly allotted to supplemented with 0 (control), 0.5, 1.0, or 1.5 mg pEGF/kg diet. Each treatment consisted of four replicates with two pigs per pen for a 14 days experimental period. Piglets were sacrificed and gastrointestinal tract samples were collected to measure mucosa morphology, mRNA expression and activities of digestive enzymes in the gastrointestinal tract of piglets at the end of the experiment. Diets supplemented with pEGF failed to influence growth performance but tended to increase jejunal mucosa weight (p < 0.09) and protein content (p < 0.07). Piglets supplemental pEGF induced incrementally the gastric pepsin activity (p < 0.05) and stimulated jejunal alkaline phosphatase (ALP) and lactase activities accompanied with the increase of jejunal ALP and maltase mRNA expression. No effect of pEGF on the activities of all enzymes in ileum except the stimulation of ileal aminopeptide N mRNA expression. These results reveal that dietary pEGF supplementation might enhance gene expression and activities of digestive enzymes in the stomach and jejunum of piglets.     

超早期断奶应激对仔猪消化酶活性的影响初报

试验选用两窝１４ 日龄杜×（ 大×长） 三元杂交商品猪,每窝１０ 头,每窝仔猪按体重平均分为断奶处理组和哺乳对照组,每组两个重复（ 栏） ,每栏５ 头猪。分别于断奶后第０（１４ 日龄） 、２ 、４ 、６ 、９ 天从每栏内随机抽取一头猪,屠宰后取胰腺和空肠内容物样品,测定胰蛋白酶、淀粉酶及脂肪酶活性。试验结果表明,断奶应激不同程度地降低了仔猪胰腺和空肠内容物中胰蛋白酶、淀粉酶和脂肪酶活性。随着断奶后时间的推移和采食量的增加,断奶仔猪空肠内容物中胰蛋白酶、脂肪酶以及胰腺中淀粉酶活性得以恢复并呈上升趋势。     

Correlation between villous height and the disaccharidase activity in the small intestine of piglets from nursing to growing

Early weaning induces villous atrophy in the small intestine. Reduction in villous height in the small intestine after weaning is associated with reductions in brush‐border enzyme activity. Body weight gain after weaning is, therefore, correlated with villous height. This evidence suggested that the maintenance of small intestinal structure and function after weaning is important for the growth of young pigs. On the other hand, the relationship between villous height and the activity of the digestive enzymes in the small intestine has not been studied with piglets from the suckling to the growing period. Five suckling piglets, four piglets in the proximal stage of weaning, four pigs in the distal stage of weaning and four growing pigs were used. The activities of lactase (LA), sucrase (SA) and maltase (MA) were determined. LA showed a positive correlation with villous height in weaning. SA and MA were positively correlated with villous height from suckling to growing. In a previous study, non‐infectious dyspeptic diarrhea was frequently observed in growing piglets on Japanese swine farms. The maintenance of villous height to retain disaccharidase activity may prevent dyspepsic diarrhea in this stage.     

Temporal changes in carbohydrate digestive capacity and growth rate of piglets in response to glucocorticoid administration and weaning age

Two experiments were conducted that demonstrated that a single injection of hydrocortisone 21-acetate (HYD, 25 mg/kg BW) administered to 6-d-old nursing piglets resulted in a twofold elevation (P less than .02) of pancreatic amylase within 2 d; activity was unaffected by an injection of 15 IU adrenocorticotropic hormone (ACTH)/kg BW (P greater than .20). Intestinal sucrase and maltase activity tended to be elevated (P less than .20) 2 and 4 d postinjection with HYD but returned to normal (uninjected) levels by 14 d of age. The normal decline of intestinal lactase activity was delayed by at least 4 d in response to both hormones (P less than .10). Organ weights were not affected by either hormone. In a separate experiment, postweaning mortality was reduced (12 vs 27%) and growth rate was substantially improved by administration of HYD to piglets 4 and 2 d prior to weaning at 14 d of age. Hydrocortisone resulted in a faster rate of gain the 1st wk postweaning for pigs weaned at 21 or 28 d. Subsequent gain by control and HYD piglets weaned on d 21 was similar, but HYD subsequently impaired growth rate of piglets weaned at 28 d of age. Growth rates of control and ACTH piglets were similar at each postweaning period regardless of weaning age (weaning age [lin.] x week postweaning [quad.] x treatment, P less than .07). This differential treatment response of daily gain may be due in part to effects on feed intake (weaning age [lin.] x week postweaning [lin.] x treatment, P less than .10). We conclude that a single injection of HYD to 6-d-old piglets precociously induces pancreatic amylase and that the sensitivity of piglets to HYD is age-dependent.     

表皮生长因子和胰岛素样生长因子-Ⅰ对断奶仔猪免疫功能的影响

选取21日龄断奶长白仔猪37头,按表皮生长因子(EG F)、胰岛素样生长因子-Ⅰ(IG F-Ⅰ)、基础日粮、自然哺乳随机分为4组,每组3重复,每个重复3头。EG F和IG F-Ⅰ的剂量为17.86μg/d,研究其对早期断奶仔猪免疫功能的影响。结果表明:EG F组和IG F-Ⅰ组脾淋巴细胞转化率均极显著(P<0.01)高于基础日粮组,空肠后段肠黏膜SIgA含量极显著(P<0.01)高于基础日粮组而且EG F组脾淋巴细胞转化率高于IG F-Ⅰ组。EG F组小肠各段黏膜上皮间淋巴细胞数极显著(P<0.01)高于基础日粮组;IG F-Ⅰ组空肠和回肠黏膜上皮间淋巴细胞数极显著(P<0.01)高于基础日粮组;EG F组回肠黏膜上皮间杯状细胞数极显著(P<0.01)高于基础日粮组;IG F-Ⅰ组回肠黏膜上皮间杯状细胞数极显著(P<0.01)低于自然哺乳组。表皮生长因子和胰岛素样生长因子-Ⅰ能提高早期断奶仔猪的免疫功能。     

Effect of swine weaning age on body fat and lipogenic activity in liver and adipose tissue

Two experiments were conducted to evaluate the effects of weaning swine at 2 or 5 wk of age on postweaning performance and fat metabolism. In the first experiment, 52 pigs were weaned at 2 or 5 wk of age with body weights determined from birth to 8 wk. The early weaned group was fed a 20% protein corn-soybean meal-oat diet containing 25% dried whey from 2 to 5 wk while both groups were fed a 20% protein cereal grain-based diet from 5 to 8 wk of age. In a second experiment, a total of 90 pigs weaned at similar ages and fed the same diet sequences were killed at weekly intervals from 2 to 8 wk of age to evaluate body fat content and lipogenesis in liver and adipose tissue. Lipogenic capacity was measured by incorporation of acetate-1 14C into the total lipid fraction in liver slices and adipose tissue minces or by monitoring liver ATP citrate lyase activity. The results demonstrate that pigs weaned at 2 wk experience a slower postweaning growth rate with lower empty body weights than those either concurrently nursing the dam or weaned at 5 wk of age. Both groups had similar body weights from 6 to 8 wk of age. The body fat content of nursing pigs increased from 2 to 5 wk of age. Pigs weaned at 2 wk lost approximately 25% of their body fat the first week postweaning while later-weaned pigs did not lose body fat postweaning. Body fat composition of both groups was similar by 8 wk of age. Lipogenic activity was higher in liver than in adipose tissue from 2 to 5 wk of age and remained relatively constant throughout the trial. Adipose tissue lipogenic activity was lower in the nursing pig but increased dramatically at 5 wk in the early-weaned group and 7 wk of age in the late weaned group. These results suggest that weaning age can affect postweaning body fat composition and that adipose contributes a greater lipogenic capacity than liver tissue as the pig matures.     

Effects of weaning on diarrhea caused by enterotoxigenic Escherichia coli in three-week-old pigs

We attempted to determine whether weaning is required for induction of diarrhea in pigs with postweaning enterotoxigenic Escherichia coli infection. Three-week-old newly weaned pigs and their suckling littermates were inoculated with the K88+ enterotoxigenic E coli strain M1823B. Fourteen of 21 weaned and 12 of 20 suckling pigs were genetically resistant to intestinal adhesion by the K88+ strain of E coli; they remained healthy, and gained weight at similar rates. Both groups of K88-resistant pigs gained weight faster, and shed fewer bacteria of strain M1823B in their feces, than did their K88-susceptible counterparts. Diarrhea developed in K88-susceptible pigs in the weaned (6 of 7 pigs) and suckling (4 of 8 pigs) groups, and 1 of the 4 affected suckling pigs died from complications resulting from diarrhea. The incidences of diarrhea, weight gain rates, and the numbers of strain M1823B shed in feces of susceptible weaned and suckling pigs were not significantly (P greater than 0.05) different. Diarrhea scores of susceptible weaned pigs were significantly (P less than 0.02) higher than those of susceptible suckling pigs on the second day after inoculation. In this experimental model, it was concluded that weaning is not required for induction of diarrhea, but may modestly increase its severity.     

Enteral exposure to crude red kidney bean lectin induces maturation of the gut in suckling pigs.

The present investigation characterized the effect of red kidney bean lectin exposure on gut maturation and function in young piglets. Eleven suckling pigs were given by stomach tube a crude red kidney bean lectin preparation (containing about 25% lectin, 400 mg/kg BW) (lectin-treated pigs) at 10, 11, and 12 d of life, and an additional 16 pigs (control pigs) were given saline instead. On the next day, the intestinal absorptive capacity was determined in vivo, and on the 14th d of life the piglets were killed and organs and small intestine samples were collected for analyses and in vitro permeability experiments. The lectin-treated pigs showed an increase in stomach weights and mucosa thickness, whereas no weight effect was found for the small intestine, spleen, liver, or adrenals. Morphometric analyses of the small intestine in lectin-treated pigs showed a decrease in villus heights, an increase in crypt depths and crypt cell mitotic indices, and fewer vacuolated enterocytes per villus and reduced vacuole size. Lectin treatment also resulted in a decrease in the absorption of different-sized marker molecules after gavage feeding, a decrease in intestinal marker permeability, and a change in small intestinal disaccharidase activities, with increased maltase and sucrase activities. The size of the pancreatic acini was also greater in the lectin-treated pigs, but no increases in enzyme content or pancreatic weight could be determined. In addition, the blood plasma levels of cholecystokinin were higher in the lectin-treated than in the control pigs. The results indicate that exposure to crude red kidney bean lectin induces structural and functional maturation of the gut and pancreatic growth in young suckling piglets. This possibility of inducing gut maturation may lead to an improvement in the piglets' ability to adapt to weaning and to an increase in the growth and health of these animals.     

早期断奶仔猪日粮中适宜蛋白质及赖氨酸水平的研究

本试验采用玉米—豆粕—鱼粉型日粮,研究不同蛋白质和赖氨酸水平对仔猪生长性能及小肠粘膜组织形态的影响。试验采用２５±３日龄断奶仔猪７２头,按２×３因子水平试验设计,即两个蛋白质水平（１８％,２０％）和三个赖氨酸水平（１．０％,１．３％,１．６％）,分为６个处理,每个处理设３个重复,试验期为２８天。于试验第１１天,每个重复选取一头仔猪,屠宰后取小肠组织样品,测定小肠各段的粘膜厚度、绒毛高度及隐窝深度。结果表明：在本试验条件下,仔猪断奶后的营养水平应分阶段供给：断奶早期,即仔猪日龄为２５～３５天、体重为６．７８～８．９２ｋｇ时,宜采用较高营养水平,即粗蛋白２０％和赖氨酸１．３％;断奶后期,即仔猪日龄为３６～５３天、体重为８．９８～１７．５２ｋｇ时,可采用较低营养水平,即粗蛋白１８％和赖氨酸１．０％;高蛋白水平导致小肠绒毛缩短及隐窝加深（Ｐ＜０．０５）,有提高仔猪腹泻率的趋势。     

The effect of meal intervals and weaning on feed intake of early weaned pigs

Feed intake was investigated in early weaned pigs housed in two environments. In the first experiment, pigs in an unfamiliar environment (removed from the sow and placed in nursery pens) were offered a dry diet either ad libitum or at different meal intervals (2, 4 and 6 h). Regardless of meal interval (ad libitum or hourly intervals), early weaned (21 d) pigs failed to consume sufficient feed for maintenance during the first 3 d postweaning. Pigs provided feed ad libitum consumed more (P less than .001) feed (142 vs 84 g/d) and gained more (P less than .05) weight (57 vs 3 g/d) than meal-fed pigs over the 7-d period. Pigs fed at 2-h intervals consumed more (P less than .001) feed than pigs fed at 4-h or 6-h intervals. Compared with preweaning levels (307 mu eq/liter), plasma free fatty acid (FFA) levels increased approximately fourfold by d 1 postweaning (1,372 mu eq/liter), then decreased through d 7 to levels below preweaning (142 mu eq/liter). The FFA levels were not affected (P greater than .1) by meal interval. In a second experiment, feed intake was investigated in weaned pigs that were allowed to consume food by a familiar method and in a familiar environment (suckling the sow). When allowed to nurse following a 24-h weaning period, weaned pigs consumed (24.3 +/- 2.8 g/suckling) the same amount (P greater than .1) as non-weaned littermates (28.7 +/- 1.8 g/suckling).(ABSTRACT TRUNCATED AT 250 WORDS)     

牡蛎多糖锌配合物对脂多糖刺激断奶仔猪生长性能和肠道健康的影响

本试验旨在探讨牡蛎多糖锌配合物对断奶仔猪生长性能和脂多糖刺激断奶仔猪血清抗氧化能力以及空肠黏膜抗炎性因子含量和二糖酶活性的影响。试验选取30头(28±1)日龄的仔猪,按体重相近的原则,随机分为空白对照组(Ⅰ组)、应激对照组(Ⅱ组)、牡蛎多糖低剂量组(Ⅲ组)、牡蛎多糖中剂量组(Ⅳ组)和牡蛎多糖高剂量组(Ⅴ组),每组6个重复,每个重复1头猪。Ⅰ组和Ⅱ组饲喂基础饲粮,Ⅲ、Ⅳ、Ⅴ组分别饲喂在基础饲粮中添加1 000、3 000和5 000 mg/kg牡蛎多糖锌配合物的试验饲粮。饲养试验30 d后,Ⅱ、Ⅲ、Ⅳ、Ⅴ组试验猪按体重腹腔注射100μg/kg的脂多糖,Ⅰ组注射等量的生理盐水。各组于注射后3 h采血,测定血清抗氧化能力;采集空肠黏膜,酶联免疫吸附试验检测白细胞介素(IL)-2、IL-10和肿瘤坏死因子-α(TNF-α)含量以及二糖酶活性。试验结果显示:1)与Ⅰ组和Ⅱ组相比,Ⅳ组和Ⅴ组平均日增重显著提高(P0.05),Ⅲ、Ⅳ和Ⅴ组料重比有降低趋势(P0.05)。2)与Ⅰ组相比,Ⅲ、Ⅳ和Ⅴ组血清总超氧化物歧化酶显著提高(P0.05);与Ⅱ组相比,Ⅲ、Ⅳ和Ⅴ组血清谷胱甘肽过氧化物酶活性显著提高(P0.05),血清丙二醛含量显著降低(P0.05)。3)与Ⅰ组相比,Ⅲ、Ⅳ和Ⅴ组空肠黏膜IL-2和IL-10含量显著提高(P0.05),其中,Ⅳ组IL-10含量还显著高于Ⅱ组(P0.05);与Ⅱ组相比,Ⅲ组和Ⅳ组空肠黏膜TNF-α含量显著降低(P0.05)。4)与Ⅱ组相比,Ⅲ、Ⅳ和Ⅴ组空肠蔗糖酶、麦芽糖酶和乳糖酶活性都有显著性地提高(P0.05)。由此可见,饲粮中添加牡蛎多糖锌配合物能有效提高断奶仔猪血清抗氧化能力和免疫耐受能力,提高空肠黏膜二糖酶的活性,对免疫应激有明显的缓解作用,其中以饲粮中添加3 000 mg/kg牡蛎多糖锌配合物效果最佳。     

Levamisole synergizes experimental F4ac+ Escherichia coli oral vaccine in stimulating ileal Peyer's patch T cells in weaned pigs

Recent findings demonstrate that priming by levamisole of weaned pigs experimentally vaccinated against postweaning colibacillosis (PWC) contributes to immune protection from challenge-induced clinical disease through stimulation of the mesenteric lymph node cells that participate in cell-mediated immunity. With the objective of better understanding the mechanisms by which levamisole induces protective mucosal cell-mediated immune response to vaccination against PWC, it was tested whether the drug synergizes experimental F4ac+ Escherichia coli oral vaccine in stimulating T cells also in the jejunal lamina propria (JLP) and ileal Peyer's patch (IPP) upon virulent challenge. Commercial crossbred pigs weaned at 4 weeks were allocated into two equal groups. The experimental group was i.m. primed with levamisole at an immunostimulatory dose of 2.5 mg/kg once daily, for 3 consecutive days, and controls received saline. Both groups were vaccinated orally with the vaccinal E. coli strain on day 0 and challenged with the virulent E. coli strain 7 days later. All pigs were killed on postchallenge day 6. The results determined by immunophenotyping of isolated cells indicate that priming by levamisole of the vaccinated weaned pigs selectively recruited and activated T cells in the IPP, a lymphoid organ-generating B lymphocytes. The pig IPP is normally populated with up to 5% of CD3+ T cells and CD6 is an activation antigen expressed exclusively by T cells in swine. Therefore, a significantly higher number of CD3+ (P < 0.01) and CD6+ (P < 0.001) cells observed within the IPP follicles of the primed-vaccinated vs. unprimed-vaccinated challenge-infected pigs suggest enhanced T cell-mediated immunity in this B-cell compartment induced by the potentiating action of the drug and vaccine. The ability of levamisole to influence interaction between activated T cells and B cells in the IPP of primed-vaccinated weaned pigs, and the possibility that this interaction plays a role in regulating B-cell maturation within the IPP follicles, are discussed.     

Effects of diets supplemented with organic acids and nucleotides on growth, immune responses and digestive tract development in weaned pigs

Sixty-eight (Experiment 1, 46 days feeding) and sixteen (Experiment 2, 21 days feeding) 21-days-old weaned pigs were allotted to four dietary treatments including control, 0.6% organic acids (OA), 0.1% nucleotides (NA) and 0.6% OA plus 0.1% NA for determining the dietary effects. In Experiment 1, OA enhanced peripheral blood mononuclear cells proliferation on day 28 and 46. The plasma immunoglobulin (Ig) A level was elevated by OA (p < 0.06) and NA (p < 0.07), respectively. In Experiment 2, NA increased plasma IgM level, and had an interactive effect with OA on ileal Peyer's patches and mesenteric lymph node lymphocyte proliferation, bile and plasma IgA levels, and jejunal crypt depth. NA elevated gastric pepsin and jejunal alkaline phosphatase activities, however, decreased ileal aminopeptidase N, sucrase or maltase activity. These results suggest that OA and NA have synergistically enhanced the gut-associated lymphocyte responses and NA modulates the digestive tract development of weaned pigs.     

Dietary supplementation of plant essential oil improves growth performance,intestinal morphology and health in weaned pigs

The present study was conducted to explore the effect of plant essential oil (PEO) on growth performance, intestinal morphology and health in weaned pigs. Twenty-four weaned pigs were assigned into four groups fed with a basal diet (CON) or basal diet containing PEO at a concentration of 50 (PEO50), 100 (PEO100) or 200 ppm (PEO200). After 21 days, pigs were slaughtered and blood and tissue samples were collected. Result showed that PEO200 group significantly increased the average daily gain (ADG) compared with CON group (p < .05). Moreover, PEO supplementation significantly improved the digestibility of DM (p < .05). However, it significantly decreased the serum triglyceride and cholesterol concentration (p < .05). Interestingly, PEO supplementation significantly increased the activity of sucrase in the duodenal and the activity of lactase in the jejunal mucosa (p < .05). Moreover, PEO supplementation improved the growth of intestinal mucosa. As compared to the CON group, the jejunum and ileum villus height were significantly elevated in the PEO200 group (p < .05). Importantly, the expression levels of critical genes associated with nutrient transportation (i.e., GLUT2 and SGLT1) and barrier function (occludin) were significantly elevated in the PEO200 group (p < .05). Moreover, the PEO100 and PEO200 group had higher propionic acid concentration and higher total bacterial gene copies in colon digesta than the CON group (p < .05) respectively. These results not only suggest that PEO has a positive role in the regulation of growth and intestinal health in weaned pigs, but also offer a potential candidate substituting the conventionally used antibiotics in the livestock industry.