Maturation of the intestinal digestion and of microbial activity in the young rabbit: impact of the dietary fibre:starch ratio.

The developmental changes of intestinal digestive potential and caecal microbial activity were described in suckling and weaned rabbits according to two feeding programmes. Two groups of thirteen litters were fed from 18 to 42 days old a "High" or a "Medium" NDF:starch ratio diet (resp. 2.7 vs 2.0, groups HL and ML) with similar protein and lipid levels, and from 42 to 70 days old the two groups were fed a "Low" NDF:starch ratio diet (1.7). From 25 to 32 days (weaning), the milk and solid feed intake were 22% and 41% higher in ML group (P<0.05), and the mortality by diarrhoea was 4 units lower (P<0.01). The whole tract digestive efficiency increased by 10% before weaning, and remained steady (organic matter) or decreased (lipids, protein) after weaning. Energy digestibility was 0.623 and 0.686 for High and Medium diets respectively. From 25 to 42 days, total enzymatic activity in intestinal content increased for chymotrypsin (5-fold, P<0.001), lipase (10-fold, P<0.001), amylase (17-fold, P<0.01) and maltase (11-fold, P<0.001), while trypsin doubled after weaning. The feeding programme only affected the amylase and maltase activities, that were higher in HL group (P<0.05). The volatile fatty acids concentration in the caecum was not significantly different among the groups, but it increased by 44% 10 days after weaning. The bacterial fibrolytic enzymes, increased by 30% after weaning and were similar among the two groups. The study revealed that the intestinal digestive maturation and the caecal microbial activity of the rabbit evolved markedly between 3 and 5 weeks of age, and was weakly affected when the NDF:starch ratio decreased from 2.7 to 2.0.     

Maturation of the intestinal digestion and of microbial activity in the young rabbit: impact of the dietary fibre:starch ratio

The developmental changes of intestinal digestive potential and caecal microbial activity were described in suckling and weaned rabbits according to two feeding programmes. Two groups of thirteen litters were fed from 18 to 42 days old a “High” or a “Medium” NDF:starch ratio diet (resp. 2.7 vs 2.0, groups HL and ML) with similar protein and lipid levels, and from 42 to 70 days old the two groups were fed a “Low” NDF:starch ratio diet (1.7). From 25 to 32 days (weaning), the milk and solid feed intake were 22% and 41% higher in ML group (P < 0.05), and the mortality by diarrhoea was 4 units lower (P < 0.01). The whole tract digestive efficiency increased by 10% before weaning, and remained steady (organic matter) or decreased (lipids, protein) after weaning. Energy digestibility was 0.623 and 0.686 for High and Medium diets respectively. From 25 to 42 days, total enzymatic activity in intestinal content increased for chymotrypsin (5-fold, P < 0.001), lipase (10-fold, P < 0.001), amylase (17-fold, P < 0.01) and maltase (11-fold, P < 0.001), while trypsin doubled after weaning. The feeding programme only affected the amylase and maltase activities, that were higher in HL group (P < 0.05). The volatile fatty acids concentration in the caecum was not significantly different among the groups, but it increased by 44% 10 days after weaning. The bacterial fibrolytic enzymes, increased by 30% after weaning and were similar among the two groups. The study revealed that the intestinal digestive maturation and the caecal microbial activity of the rabbit evolved markedly between 3 and 5 weeks of age, and was weakly affected when the NDF:starch ratio decreased from 2.7 to 2.0.     

Adaptability of the digestive function according to age at weaning in the rabbit: I. Effect on feed intake and digestive functionality

The functional adaptability of the digestive system to the level of feed intake was investigated in the young rabbits by comparing two groups of 12 litters each, weaned at 21 (W21) or 35 (W35) days of age. From 14 days onwards, rabbits were fed a pelleted feed (NDF: 332 g/kg, CP: 177 g/kg, starch: 98 g/kg, as-fed basis). Until 49 days of age, the profile of digestive enzymes was weekly determined in the small intestinal content and mucosa, as well as caecal fermentation traits and fibrolytic activities. In the W21 group, the solid feed intake was increased by 57% between 21 and 35 days (P < 0.01), while the daily body growth was lower from 21 till 42 days (-17%, P < 0.05) when compared with the W35 group. Activities of enzymes of pancreatic origin were only scarcely influenced by the weaning age. In the W21 group, amylase activity tended to be lower at 28 days of age (-36%, P = 0.064), and trypsin activity was decreased by 31% at 49 days of age (P < 0.01). Lipase activity was similar in both weaning groups. Duodenal and jejunal activities of maltase and aminopeptidase N (APN) were higher on day 28 in the W21 group as compared with the W35 group (×1.4 to ×2.4, respectively, P < 0.05). On day 35, duodenal APN activity was twice as higher in the W21 group than in the W35 group (P < 0.01). In caecum, major differences between both weaning groups were observed at 28 days of age with a decrease in ammonia concentration (-43%, P < 0.01) in W21 compared with W35 rabbits. Conversely, the acetate proportion was 5% higher in the W21 group (P < 0.01) on day 28. In conclusion, the digestive tract of early-weaned rabbits showed some adaptative properties in response to nutritional environment changes, but they were insufficient to maintain their growth rate.     

Adaptability of the digestive function according to age at weaning in the rabbit: II. Effect on nutrient digestion in the small intestine and in the whole digestive tract

The ability of young rabbits to digest a solid diet was evaluated according to the weaning age: 21 (W21, 12 litters) or 35 (W35, 12 litters) days of age. From 14 days onwards, the rabbits were fed the same pelleted feed. Three methods were compared to estimate the faecal digestibility in the young rabbits, between 24 to 28 and 38 to 42 days. Digestive balance at ileal and faecal levels was determined for the main nutrients provided by milk and solid feed. The W21 rabbits increased their solid feed intake only 2 days after their weaning, when compared with suckling rabbits. Thus, their crude protein (CP) intake remained lower until 26 days compared with the W35 rabbits (from 41%, P < 0.01), as well as their crude fat intake until 28 days (from 72%, P < 0.001). On the contrary, the W35 rabbits increased their solid feed intake without a delay after weaning, quickly reaching the intake level of the W21 rabbits. The amounts of organic matter (OM) and CP reaching the caecum were increased on day 28 by 56% and 42% in the W21 rabbits compared with the W35 rabbits, respectively (P < 0.05), and were similar between groups on day 42. Starch ileal digestibility coefficients were 94·2% and 95·4% in 28- and 42-day-old rabbits, respectively, irrespective of the weaning age. The amount of starch flowing through the ileo-caecal junction was low and only tended to be higher on day 28 in the W21 group (0.20 v. 0.15 g/day in the W35 group, P = 0.10). The digestive balance pointed out that the digestible energy intake was similar between weaned and suckling rabbits from 23 to 27 days, a phenomenon partly explained by a high ability of the W21 rabbits to digest starch (98%) and NDF (36%). Indeed, the amounts of starch and NDF digested by the W21 group were 2.0- and 2.4-fold higher than those of the W35 rabbits at this period (P < 0.001). However, they ate 20% less digestible proteins than still-suckling rabbits (P < 0.001). From 38 till 42 days, only a lower ability of the W21 rabbits to digest lipids was detected (P < 0.05). In conclusion, early-weaned rabbits were able to adapt quickly to digest large amounts of starch and fibres.     

Phosphatidylcholine synthesis in the developing small intestine.

1. Phosphatidylcholine synthesis in the foetal, newborn and adult small intestine of rats was studied by determination of cytidine diphosphocholine-1,2-diacylglycerocholine phosphotransferase (cholinephosphotransferase) and acyl-CoA-1-acyl-sn-glycerol-3-phosphocholine acyltransferase (lysophosphatidylcholine acyltransferase) activities and the incorporation of [1-14C]oleic acid into phosphatidylcholine. 2. Cholinephosphotransferase activity was low in foetal jejunum and ileum, increased 3-4 fold in the ileum by 6 days of age and by 12 days in the jejunum. Jejunal activity remained constant throughout weaning; ileal activity gradually decreased to values 25% of that of the jejunum. 3. Lysophosphatidylcholine acyltransferase activity was high in foetal jejunum and ileum, decreased 70% immediately after birth in the jejunum and increased to adult values by 12 days of age. Ileal activity decreased by 20% after birth, but decreased more rapidly at weaning to 30% of the activity in jejunum. 4. Initial rates and steady-state incorporation of [1-14C]oleic acid into phosphatidylcholine by jejunal rings of 10 day-old rats exceeded that observed in jejunal rings from adult rats by 2-4-fold. 5. In the postnatal jejunum, neither cholinephosphotransferase and lysophosphatidylcholine acyltransferase activities nor oleic acid incorporation were stimulated by cortisone administration in vivo.     

Changes in abundance of Lactobacillus spp. and Streptococcus suis in the stomach, jejunum and ileum of piglets after weaning

This present study investigated the changes in bacterial community composition, with an emphasis on Lactobacillus spp. and Streptococcus suis populations as potentially beneficial and harmful groups, in the stomach, jejunum and ileum of piglets after weaning (21 days postpartum) by 16S rRNA gene-based methods. Denaturing gradient gel electrophoresis analysis showed that, after weaning, predominant bands related to Lactobacillus spp. disappeared and were replaced by potential pathogenic species, such as Peptostreptococcus anaerobius, Moraxella cuniculi, S. suis and Porphyromonas catoniae. Real-time PCR revealed that the abundances of lactobacilli and Lactobacillus sobrius as a proportion of total bacterial abundance were significantly lower in the stomach, jejunum and ileum of weaned piglets than in 21-day-old piglets. A specific and sensitive real-time PCR assay was developed for quantification of the important pathogen S. suis within gastrointestinal microbiota. The assay showed that S. suis predominated in the stomach samples of weaned piglets with population levels up to 10(7) copies g(-1) digesta, while it was not detected in the stomach before weaning. Streptococcus suis was not dominant in the jejunum and ileum digesta before weaning, but became dominant after weaning, with population levels up to 10(7) copies g(-1) digesta. The results demonstrated for the first time the postweaning dominance of the potentially harmful S. suis in piglet intestine. The results also suggest that the defensive barrier of the stomach can be impaired as S. suis became dominant while the proportion of Lactobacillus populations decreased after weaning, which may further result in an increase of S. suis abundance in the intestine.     

不同来源乳铁蛋白对幼鼠肠道发育的影响

目的 探究哺乳期乳铁蛋白（lactoferrin，LF）的缺失及不同来源LF补充后对幼鼠肠道发育的影响。方法 以LF基因敲除型雌鼠作为哺乳母鼠造成幼鼠哺乳期无LF的摄入，且从幼鼠出生第3~21天每日人工饲喂100 mg/kg 牛血清白蛋白（BSA）、牛源乳铁蛋白（bovine Lactoferrin，bLF）及重组人源乳铁蛋白（recombinant human Lactoferrin，rhLF），于幼鼠21日龄取样，测定各组小鼠小肠发育指标。结果 在本实验周期下，哺乳期rhLF的补充显著性增加小鼠回肠绒毛长度/隐窝深度值（P<0.05），且上调回肠Occludin和ZO-1基因的表达（P<0.05），增加小鼠十二指肠、空肠和回肠麦芽糖酶酶活/乳糖酶酶活比值（P<0.05），表明哺乳期rhLF的补充能够增强小鼠肠道消化吸收能力和肠屏障功能；哺乳期bLF的补充显著增加小鼠十二指肠及回肠麦芽糖酶活性/乳糖酶活性比值（P<0.05）。结论 对于哺乳期无LF摄入的乳鼠来说，哺乳期间LF的补充能够增强乳鼠肠道对营养物质的消化吸收能力、促进肠道的发育成熟、增强肠道屏障功能，并且，本实验中rhLF表现出比bLF更加有效的作用。     

Effect of Weaning on Small Intestinal Structure and Function in the Piglet

Fifty-four piglets were selected from 12 litters weaned at 17 (Treatment 1), 21 (Treatment 2), 28 (Treatment 3) and 35 (Treatment 4) days old, respectively, to determine the effect of weaning age on small intestinal villus morphology, immunology and histochemistry. From proximal duodenum, proximal jejunum, distal jejunum and middle ileum, intestinal samples with three replicates (piglets) in each treatment were taken at 18, 22, 28 and 36; 22, 28, 36 and 43; 28, 36, 43, and 50; and 18, 22, 28, 36, 43 and 50d of age in Treatment 1, 2, 3 and 4, respectively. This was equivalent to 12h, 3d, 1 week, 2 week postweaning in Treatment 1; 12h, 1 week, 2 week, 3 week postweaning in Treatment 2 and 3, and all the same age in Treatment 4 as in Treatment 1, 2, 3, respectively. The results showed that villous height of duodenum and proximal jejunum decreased significantly in Treatment 1 and 3. Crypt depth in the duodenum, proximal jejunum and ileum also decreased significantly in Treatment 1. Date had significant effect on villous height of the duodenum, distal jejunum and ileum with the shortest on day 29 and crypt depth of all positions increased with piglet age except the crypt depth in proximal jejunum decreased on day 50. Weaning age and day of age had significant effects on intraepithelial lymphocyte (IEL) number and goblet cell (GC) number at all positions of small intestinal mucosa in piglets. The number of IEL at all segments of small intestinal mucosa in Treatment 3 increased significantly compared to those in other treatments, but IEL number at all locations of small intestinal mucosa in Treatment 2 decreased significantly compared to those in other treatments. The number of GC in small intestinal mucosa increased significantly in early-weaned (< day 21) piglets. It appears that providing fluid milk replacer for a few days postweaning could dramatically reduce the negative impact of weaning on villous morphology and digestive and absorptive function, especially in pigs weaned prior to 3 week of age. Finally, as weaning age was reduced, GC had a greater role in intestinal duct protection.     

Effect of cortisone on the developmental pattern of the neutral and the acid β-galactosidases of the small intestine of the rat

1. The developmental pattern and effect of cortisone on acid beta-galactosidase and neutral beta-galactosidase were studied in postnatal rats by a recently proposed method for their independent determination. 2. After birth the acid beta-galactosidase activity increases in the ileum, whereas it decreases slightly in the jejunum. On day 16 after birth the activity in the ileum decreases and in 20-day-old rats activity in both parts of the intestine decreases to adult values. In suckling animals the activity in the ileum exceeds the jejunal activity severalfold and in adult animals the activity in the jejunum is slightly higher than that in the ileum. 3. Neutral beta-galactosidase activity is high after birth and decreases in both jejunum and ileum after day 20 after birth. In 12-20-day-old rats activity in both parts is essentially the same, but in adult animals jejunal activity exceeds ileal activity four-to five-fold. 4. Cortisone (0.5, 2.0 or 5.0mg/100g body wt. daily for 4 days) does not influence the activity of either enzyme in 60-day-old rats. Acid beta-galactosidase activity is decreased after cortisone treatment in 8-, 12-, 16-and 18-day-old rats, with sensitivity to cortisone increasing with the approach of weaning. No effect of cortisone on acid beta-galactosidase is seen in 8-day-old rats. Neutral beta-galactosidase activity is increased in the ileum of 8-, 12-, 16- and 18-day old rats, but only in the jejunum of 8-and 12-day-old rats.     

Disaccharidase activities after jejunoileal bypass in rat

Digestive enzymatic activities (maltase, lactase and sucrase) have been determined in the intestinal mucosa of rats subjected to a jejunoileal bypass of 45 cm. The weight and protein content of the mucosa (mg/cm) were significantly decreased in the bypassed segment and significantly increased in the unbypassed segment, as compared to control rats. Maltase, lactase and sucrase specific (U/g protein) and total activity (U/cm intestine) were significantly decreased in the bypassed jejunum, compared to sham-operated rats. In the ileum, maltase specific and total activities increased in bypassed animals while the lactase and sucrase activities remained unchanged.     

Effect of early antibiotic intervention on specific bacterial communities and immune parameters in the small intestine of growing pigs fed different protein level diets

Antibiotics are designed to affect gut microbiota and subsequently gut homeostasis. However, limited information exists about short- and long-term effects of early antibiotic intervention (EAI) on gut homeostasis (especially for the small intestine) of pigs following antibiotic withdrawal. We investigated the impact of EAI on specific bacterial communities, microbial metabolites and mucosal immune parameters in the small intestine of later-growth-stage pigs fed with diets differing in CP levels. Eighteen litters of piglets were fed creep feed with or without antibiotics from day 7 to day 42. At day 42, pigs within each group were offered a normal- or low-CP diet. Five pigs per group were slaughtered at days 77 and 120. At day 77, EAI increased Enterobacteriaceae counts in the jejunum and ileum and decreased Bifidobacterium counts in the jejunum and ileum (P < 0.05). Moreover, tryptamine, putrescine, secretory immunoglobulin (Ig) A and IgG concentrations in the ileum and interleukin-10 (IL-10) mRNA and protein levels in the jejunum and ileum were decreased in pigs with EAI (P < 0.05). At day 120, EAI only suppressed Clostridium cluster XIVa counts in the jejunum and ileum (P < 0.05). These results suggest that EAI has a short-term effect on specific bacterial communities, amino acid decarboxylation and mucosal immune parameters in the small intestine (particularly in the ileum). At days 77 and 120, feeding a low-CP diet affected Bifidobacterium, Clostridium cluster IV, Clostridium cluster XIVa and Enterobacteriaceae counts in the jejunum or ileum (P < 0.05). Moreover, feeding a low-CP diet increased the concentrations of Igs in the jejunum and decreased pro-inflammatory cytokines levels in the jejunum and ileum (P < 0.05). At day 120, feeding a low-CP diet increased short-chain fatty acid concentrations, reduced ammonia and spermidine concentrations and up-regulated genes related to barrier function in the jejunum and ileum (P < 0.05). These results suggest that feeding a low-CP diet changes specific bacterial communities and intestinal metabolite concentrations and modifies mucosal immune parameters. These findings contribute to our understanding on the duration of the impact of EAI on gut homeostasis and may provide basis data for nutritional modification in young pigs after antibiotic treatment.     

Circadian rhythms in digestive enzymes in the small intestine of rats. I. Patterns of the rhythms in various regions of the small intestine.

The activities of the digestive enzymes, maltase [EC 3.2.1.20], sucrase [EC 3.2.1.26], trehalase [EC 3.2.1.28], Leucine aminopeptidase [EC 3.4.11.1], and alkaline phosphatase [EC 3.1.3.1] were measured in various regions of the small intestine of rats. The activities of all these enzymes were much higher in the jejunum than in the ileum, and in the distal regions of the ileum no sucrase, trehalase or alkaline phosphatase activity was detected. In the jejunum, the activities of all the enzymes tested exhibited clear circadian variations with the highest activity at 0000-0400 h and the lowest at 1200 h when the rats were fed ad libitum. In the ileum, maltase and sucrase also exhibited circadian variations, but the amplitude of the rhythm was smaller than that in the jejenum. Trehalase and alkaline phosphatase did not show any circadian variation in the ileum. Leucine aminopeptidase showed a circadian variation in the ileum with the same amplitude as in the jejunum. The phase of the circadian variations shifted about half a day when the rats were fed in the daytime, but the amplitude of the rhythm did not change.     

Effect of protein deficiency in the female rat diet during pregnancy and lactation on the activity of the membrane and soluble forms of digestive enzymes in the offspring small intestine

Protein deficiency in female rats diet during pregnancy and lactation resulted in deceleration of induction of sucrase both forms in the jejunum and ileum; in acceleration of induction of the maltase membrane from in the jejunum; and in suppression of the lactase membrane form in the ileum; in earlier forming of the adult-type distribution of activity of the membrane form of intestinal alkaline phosphatase and in a decrease in activity of the enzyme soluble form. The findings are corroborated by a suppression of activities of the membrane and soluble forms of the small intestine digestive enzymes in 30-day old rat pups fed with a control (adequate) ration starting 21 days after the birth.     

Milk intake in blue fox (Alopex lagopus) and silver fox (Vulpes vulpes) cubs in the early suckling period

Milk intake of fox cubs (2-16 days of age; body weight, 96-649 g) in ten blue fox litters and ten silver fox litters were measured by the water isotope dilution (WID) technique following a single intraperitoneal injection of tritiated water (3HHO). Litter size varied from four to 14 in blue foxes and from three to eight in silver foxes. Silver fox cubs had higher birth weights than blue foxes. Inter-species body weights and growth rates were apparently dependent on litter size and the dam's constitution. In both species growth rate increased with age and body weight (7-35 g per day). In the cubs, the biological half-life of body water turnover (BWT) rose from 1.5 days at 2-3 days of age to 2.5 days at 13-16 days of age, although a considerable scatter was seen. The mean daily milk intake of the cubs varied with body weight, from 31 to 193 g per day, whereas daily milk intake per unit of body mass remained stable at 30-35 g per 100 g body weight. The ratio of milk intake to body weight gain varied considerably among cubs, averaging 4.5 g/g during the 3-week experimental period. In suckling fox cubs, the calculated daily intake of metabolically energy (ME) corresponded fairly with the estimated energy requirements for growth and maintenance of the young. Finally, the applicability and the accuracy of the WID technique was evaluated in ten 3-week-old fox cubs, by tube-feeding with a milk replacer for 48 h, which documented that the daily rates of milk intake and water turnover can be accurately measured in suckling fox cubs by the WID technique following a single injection of 3HHO.     

Transitory disturbances in growing lactating rabbits after transient doe-litter separation

To determine the effect of a transient doe-litter separation (48 h) on milk production and feed intake from 1 to 21 days post-partum, a control group (C) in which litters had free access to nursing, and a biostimulated group (B) in which litters were separated from their does from d 9 to d 11 post-partum were used. Total milk production was higher in (C) than in (B) does (5090+/-1.1 g vs. 4593+/-150 g, P < 0.05). On days 12, 13, 14 and 15 of the lactation period, milk production was 40% (P < 0.0001), 18% (P < 0.05), 15% (P < 0.05), and 15% (P < 0.01) higher in (C) than in (B), respectively. No significant differences were observed in feed intake during the period studied (7961+/-352 g in (C) does, and 7834+/-329 g in (B) does). After fasting, 11-day-old kits showed lower gut weight, body weight, empty stomach relative weight (RW), stomach content RW and small intestine RW (P < 0.05), but the differences disappeared at 21 days of age. A reduction in villous height (P < 0.065) was observed in separated kits at 11 days old compared to 9- and 11 -day-old control kits (579.0+/-28.4 vs. 664.64+/-27.6, and 724.33+/-24.1 microm, respectively), but no differences were observed at either 16 or 21 days of age. Specific jejunal lactase activity increased significantly in 11-day-old separated kits (P < 0.05). A significant increase in sucrase activity at 21 days in both groups (P < 0.05) was detected. In conclusion, a fasting period of 48 h at 9 days of age does not compromise the subsequent development of certain digestive parameters of young rabbits.     

七味白术散联合蒙脱石散对腹泻幼鼠肠道菌群及免疫功能影响的研究

摘要 目的：探讨七味白术散联合蒙脱石散对腹泻幼鼠肠道菌群及免疫功能影响的研究。方法：选择SD雄性幼鼠30只,随机分为对照组、模型组、七味白术散组、蒙脱石散组、七味白术散联合蒙脱石散组,对照组与模型组灌胃给予0.2 mL/10生理盐水,七味白术散组给予0.2 mL/10 g七味白术散,蒙脱石散组给予0.2 mL/10 g蒙脱石散,七味白术散联合蒙脱石散组给予0.2 mL/10 g七味白术散+0.2 mL/10 g蒙脱石散,5组每天定时灌胃一次,均连续给药7天。对比腹泻指数、平均稀便级、稀便率、脾重、胸腺重指数、血清淀粉酶、血清D-木糖水平、回肠、结肠、空肠黏膜厚度及小肠内容物细菌增殖。结果：与对照组相比,其他组脾重、胸腺重指数、血清淀粉酶及D-木糖水平、双歧杆菌、乳酸杆菌数量较低,腹泻指数、平均稀便级、稀便率、回肠、结肠、空肠黏膜厚度、大肠杆菌较高（P<0.05）;与模型组相比,蒙脱石散组、七味白术散组、七味白术散联合蒙脱石散组的脾重、胸腺重指数、血清淀粉酶及D-木糖水平、双歧杆菌、乳酸杆菌数量较高,腹泻指数、平均稀便级、稀便率、回肠、结肠、空肠黏膜厚度、大肠杆菌较低（P<0.05）;与蒙脱石散组相比,七味白术散组、七味白术散联合蒙脱石散组的脾重、胸腺重指数、血清淀粉酶及D-木糖水平、双歧杆菌、乳酸杆菌数量较高,腹泻指数、平均稀便级、稀便率、回肠、结肠、空肠黏膜厚度、大肠杆菌较低（P<0.05）;与七味白术散组相比,七味白术散联合蒙脱石散组的脾重、胸腺重指数、血清淀粉酶、D-木糖水平、双歧杆菌、乳酸杆菌数量明显较高,腹泻指数、平均稀便级、稀便率、回肠、结肠、空肠黏膜厚度、大肠杆菌较低（P<0.05）。结论：七味白术散联合蒙脱石散可明显改善腹泻幼鼠的腹泻症状,可能与其可调整腹泻幼鼠肠道菌群及免疫功能有关。     

The effect of heat on the intestinal and pancreatic levels of amylase and maltase of laying hens and broilers

The effects of exposing laying hens and broilers daily to intermittent periods of 4 hr heating at 42 degrees C on the intestinal and pancreatic levels of amylase and maltase were investigated. The initial exposure to heat, characterized by heat stress, brought about a significant increase in the duodenum and jejunum parts of the tetra breed hen and only in the duodenum of broilers. The levels of amylase in the distal parts of the intestine of both breeds sharply decreased. The increase in amylase levels in the proximal parts of the intestine under the conditions of initial heating vanished after 3 days of heating; its levels continued to fall in the distal parts. In heat acclimatized laying hens the levels of amylase were lower than those of the control hens both in the intestine and pancreas. The pancreatic level of amylase was reversely related to the levels in the intestine. It is assumed that the intestinal level of amylase is regulated by the pancreas. These findings indicate that the pancreas plays an important role during the adaptation of chickens to heat, through the regulation of intestinal level of amylase. The response in maltase level to heat stress and heat acclimatization was insignificant.     

Changes in digestive enzyme activity, intestine morphology, mucin characteristics and tocopherol status in mink kits (Mustela neovision) during the weaning period

Weaning of livestock mammals is often associated with digestive problems related to profound changes in the physiology of the gastrointestinal tract. This study was undertaken to study the developmental changes in the gastrointestinal tract of mink kits during the period of 34 to 59 days of age. Twenty-four mink kits from eight litters were included in the experiment. The dams and their litters were kept under standard farm conditions. The dams and the kits were fed a diet consisting of 48.1% protein, 40.7% fat and 11.1% carbohydrate of metabolizable energy. The mink kits were weaned at 42 days of age. At 34, 47 and 59 days of age, one male mink kit from each litter was euthanized. The activity of amylase, trypsin, chymotrypsin and lipase in the pancreatic tissue increased during the experimental period, whereas the activity of carboxyl ester hydrolase remained constant. The vitamin E concentration in plasma was stable from 34 to 59 days of age, whereas the concentration decreased in the liver. The stereochemical composition of α-tocopherol showed a steep decrease in the concentration of the biologically most active natural isomer in both plasma and liver through the whole weaning period, whereas the biologically less active 2S isomers showed a clear increase. The concentration of bile salts did not change during the experimental period. The villous height increased in the proximal part of the small intestine and decreased in the distal part, whereas the crypt depth was doubled in both the proximal and distal part of the small intestine. The mucin-staining area on the villi was markedly reduced during the experimental period but no change in the mucin-staining area in the crypts was observed.     

Soluble neutral and acid maltases in the suckling-rat intestine. The effect of cortisol and development

The 100000g supernatants from 13-day-old suckling-rat intestinal homogenates contained 43.5% of the total intestinal maltase activity, compared with 7.1% in weaned adult rats aged 40 days. The soluble maltase activity was separated on Sepharose 4B into two quantitatively equal fractions at pH6.0, one containing a maltase with a neutral pH optimum and the other a maltase with an acid pH optimum. The neutral maltase was shown to be a maltase-glucoamylase identical with membrane-bound maltase-glucoamylase in molecular weight, heat-sensitivity, substrate specificity, K(m) for maltose and K(i) for Tris. The soluble enzyme was induced by cortisol, but the ratio of the soluble to bound enzyme fell during induction. Solubility of the neutral maltase was not accounted for by the action of endogenous proteinases under the preparative conditions used. It is postulated that the soluble neutral maltase is a membrane-dissociated form of the bound enzyme and that the relationship between these two forms is modulated by cortisol. The acid maltase generally resembled acid maltase of liver, muscle and kidney. It was shown to be a maltase-glucoamylase with optimal activity at pH3.0, and molecular weight of 136000 by density-gradient centrifugation. At pH3.0 its K(m) for maltose was 1.5mm. It was inhibited by turanose (K(i)=7.5mm) and Tris (K(i)=5.5mm) but not by p-chloromercuribenzoate or EDTA. Some 55% of its activity was destroyed by heating at 50 degrees C for 10min. The acid maltase closely resembled beta-glucuronidase and acid beta-galactosidase in its distribution in the intestine, response to tissue homogenization in various media, and decrease in activity with cortisol treatment and weaning, indicating that it was a typical lysosomal enzyme concentrated in the ileum.     

Effect of pentagastrin, secretin and cholecystokinin on growth and differentiation in organ cultured rabbit small intestine

The effect of pentagastrin, secretin and cholecystokinin on biochemical parameters of mucosal growth and differentiation was studied in organ cultured rabbit jejunum and ileum. Pentagastrin at 0.05-5.0 microgram/ml did not affect DNA content of the biopsy, but led to a significant decrease of sucrase and alkaline phosphatase activity in the ileum. Secretin prompted a significant decrease of DNA and protein in the ileum at a level of 10(-7) and 10(-5) M, but had no effect in the jejunum. Of the brush border enzymes, sucrase and alkaline phosphatase were suppressed in both parts of the intestine both with respect to specific activity and total biopsy content. Cholecystokinin, like pentagastrin, did not influence DNA or protein content, but reduced sucrase, maltase and alkaline phosphatase activity. HMG-CoA reductase, the key enzyme of cholesterol synthesis, was not significantly affected by any of the three hormones tested. When brush border enzymes or DNA from desquamated cells were measured in the post-culture medium, no consistent effect of any gastrointestinal hormone was apparent. The present study demonstrates a direct "antitrophic" effect of secretin in cultured mucosa. Pentagastrin and cholecystokinin did not influence mucosal DNA content in vitro but apparently inhibited villus cell differentiation.