Histology and Mucin Histochemistry of The Digestive Tract of Yellow Catfish, Pelteobagrus fulvidraco

The histology and characteristics of mucins secreted by epithelial mucous cells of the digestive tract in yellow catfish, Pelteobagrus fulvidraco were investigated using light microscope and transmission electron microscope. The digestive tract was divided into a pharynx, oesophagus, U-shaped stomach (with a cardiac, fundic and pyloric part) and intestine, composed of anterior intestine, middle intestine and posterior intestine, which consisted of a mucosa (epithelial layer), lamina propria-submucosa, muscularis and serosa. A large number of isolated longitudinal striated muscular bundles were present in the lamina propria-submucosa of pharynx. Goblet cells were observed throughout the digestive tract, except in the stomach. In the cardiac and fundic stomach, a plenty of gastric glands were observed, whereas they were absent in the pyloric part. Numerous mitochondria and endoplasmic reticulum were observed in the columnar epithelial cells of the intestine, especially of the anterior part. The epithelial mucous cells contained neutral or other two mixtures of acid and neutral mucins, the first being the most common. The neutral mucin was the only type of mucins in the stomach, anterior intestine and middle intestine. The results of this study will be helpful for understanding the digestive physiology and diagnosing some gastrointestinal diseases in yellow catfish.     

Histochemical analyses of digestive enzymes in the intestine of adult large-scaled gurnard (lepidotrigla cavillone, lacepède, 1801)

Localization and activity levels of the following digestive enzymes in the intestine of free-living large-scaled gurnard were determined: non-specific esterase, alkaline and acid phosphatase as well as aminopeptidase. Enzymatic activity of the four enzymes was confirmed in all intestine parts but with different distribution through the enterocytes and varying in diverse intensity according to intestine part. This research is part of a broader research project on the biology of economically important fish from the Adriatic Sea. Our study reveals that in the large-scaled gurnard, the middle and posterior intestinal segments play the major role in digestion and absorption of proteins, whereas all parts of the intestine participate in lipid absorption and intracellular digestion. The high protein and lipid content in the diet of the large-scaled gurnard is most likely responsible for high activities of esterase, alkaline phosphatase and aminopeptidase, as they are involved in digestion and absorption of proteins and lipids.     

猪大肠消化生理的研究进展

人们对猪胃期消化生理和小肠消化生理已经研究得比较清楚,随着猪肠道消化生理研究的深入,动物营养专家十分关注猪大肠的消化生理。猪大肠主要进行微生物消化,以进入大肠的未消化饲料残渣、脱落的肠黏膜和胃肠道消化酶为底物,经过大肠消化相关的微生物发酵产生以挥发性脂肪酸为主的产物,大部分产物被动物吸收利用,为动物生长提供能量。本文分别从发酵底物、发酵产物及其对猪消化能的贡献和大肠微生物3个角度对猪大肠消化生理展开综述。     

Migratory responses of hemocytes to Vibrio parahaemolyticus in the alimentary tract of an estuarine neritid gastropod, Clithon retropictus.

Migratory responses of hemocytes to Vibrio parahaemolyticus strain D3 in the alimentary tracts of an estuarine neritid gastropod, Clithon retropictus, and a related marine neritid, Nerita albicilla, were examined under the scanning electron microscope. After ingesting the strain, active responses were seen at the esophagus, stomach and anterior intestine of adult C. retropictus and at the middle and posterior intestines of adult N. albicilla. When the alimentary tracts were isolated from the gastropod and incubated in vitro with strain D3, active response was induced at the most parts of the tract of the adult gastropods and at the stomach and the anterior intestine of juvenile C. retropictus. The responding hemocytes were confirmed to be granulocytes in the semi-thin sections of the tract of adult C. retropictus. The poor hemocyte responses at the middle and posterior intestines of juvenile C. retropictus might support the colonization of the organism there.     

丁酸钠对鱼类肠道消化吸收的影响研究进展

与畜禽等动物相比,鱼类消化系统不健全,消化酶活性低,而植物性原料中常含有抗营养因子和毒性成分等,易导致肠道损伤及肠炎等疾病。丁酸等短链脂肪酸可显著改善鱼类生长性能,增强鱼体健康及抗氧化和抗应激能力。因丁酸气味不佳,影响动物适口性,丁酸钠作为丁酸的替代物,呈固态且不易挥发,易于添加使用。丁酸钠可促进肠道上皮细胞发育,改善肠道形态结构,保持肠道黏膜屏障完整,对损伤的肠道黏膜加以修复,刺激上皮细胞内mRNA和蛋白质合成,加速肠上皮细胞增殖,增加绒毛高度,促进消化吸收。丁酸钠能破坏有害菌DNA结构,蛋白质不能合成,使有害菌不能进行正常分裂,抑制肠道有害菌的生长繁殖,促进有益菌群的增殖,维持肠道菌群平衡,菌群多样性显著提高。丁酸钠可通过刺激消化酶的分泌来改善鱼类消化,降低劣质蛋白原料对肠道损伤,抑制鱼肠道细胞凋亡,减少肠道炎症发生,显著改善鱼类肠道屏障的功能。丁酸钠还可用作生长促进剂及免疫刺激剂,在低鱼粉饲料中使用可降低饲料成本,促进鱼类生长发育。因此,丁酸钠是绿色安全可替代抗生素的添加剂,同时植物蛋白适当替代鱼粉可提高经济效益。作者就丁酸钠对肠道消化吸收功能的影响进行重点阐述,以期为鱼类等水产...     

Effects of different protein sources completely replacing fish meal in low‐protein diet on growth performance,intestinal digestive physiology,and nitrogen digestion and metabolism in nursery pigs

The study compared the effects of selected proteins replacing fish meal in low‐protein diets on piglets’ growth performance, intestinal digestive physiology, and nitrogen digestion and metabolism. Five reduced CP, amino acid (AA)‐supplemented diets containing 4% of either S50, HP300, concentrated degossypolized cottonseed protein (CDCP), P50, or fish meal were assigned to six pens with 11 pigs for a 28‐day study period. Compared with fish meal, dietary proteins did not affect growth performance, apparent total tract digestibility (ATTD) of nutrients, serum hormone levels and biochemical parameters, apparent ileal digestibility (AID) of CP and most AA, colonic short‐chain fatty acid (SCFA) contents, duodenal and ileal morphology, digestive enzyme activity, and pH in small intestine of piglets. However, HP300, CDCP, and P50 decreased (p < 0.05) fecal N excretion per weight gain. AID of Ile in S50 and HP300 and Glu in P50 were improved (p < 0.05), and AID of Gly in other proteins was reduced (p < 0.05). S50 and P50 lowered (p < 0.05) the contents of colonic isobutyric and isovaleric. S50 and HP300 reduced (p < 0.05) jejunal villus height. CDCP increased (p < 0.05) the pepsin activity in stomach. S50, HP300, and CDCP decreased (p < 0.05) pH in the proximal colon. Overall, the selected proteins could completely replace fish meal in low‐protein diet without impairing piglets’ growth via maintaining intestinal digestive physiology, and nitrogen digestion and metabolism.     

断奶仔猪肠道健康与免疫调控

断奶应激一直是困扰现代养猪业的难题,由于幼龄仔猪消化系统和免疫系统都尚未发育成熟,早期断奶容易造成仔猪胃肠道功能紊乱,诱发仔猪断奶综合征。肠道是断奶仔猪消化食物、吸收营养的主要场所,也是体内最大的免疫器官之一。因此,通过研究仔猪肠道健康,阐明仔猪肠道生理结构及功能的发育规律,分析仔猪断奶前后肠道免疫调控特点,为不同日龄断奶仔猪确定合理的营养对策具有十分重要的意义,文章就近年来国内外仔猪肠道生理及免疫调控的研究进展进行综述。     

丁酸钠对肉鸡肠道形态与消化吸收功能影响的研究进展

肠道是肉鸡重要的消化、内分泌及免疫器官，肠道健康主要依赖于营养物质、微生物菌群和肠道黏膜之间的动态平衡。肠道消化吸收功能与肠黏膜上皮细胞的生长及肠道形态结构的完整性直接相关。研究表明，丁酸钠作为能量来源，可刺激肉鸡肠道上皮细胞增殖并改善肠道黏膜形态，促进绒毛生长和肠道组织发育。丁酸钠通过肠道游离脂肪酸受体FFAR2和FFAR3介导肠道内分泌细胞分泌多种激素，促进胃肠黏膜的发育，刺激胃和胰腺分泌消化酶，促进养分消化吸收。丁酸钠是肠道稳态的重要调节因子，可刺激黏蛋白的产生，增加黏液层厚度，降低结肠上皮的通透性，维持肠道完整性和黏膜屏障功能。丁酸钠促进宿主防御肽（HPDs）的合成，抑制肠道内有害菌的增殖，降低内毒素对肠黏膜上皮细胞的损伤。丁酸钠通过抑制NF-κB激酶（IKK）下调促炎症途径，抑制NF-κB的活化，预防肠黏膜炎症发生，进而促进消化吸收和保护肠道健康。综上，丁酸钠具有肠道保护和抗菌作用，可增强肠道完整性，促进营养物质的消化吸收，提高免疫力和抗病力。在饲料工业禁抗的背景下，对抗生素替代品丁酸钠的研究和应用非常重要，作者就丁酸钠对肠道功能的作用机制进行重点阐述，以期为其在肉鸡饲料中替代抗生素提供科学依据。     

Division of Chinese soft‐shelled turtle intestine with molecular markers is slightly different from the morphological and histological observation

The Chinese soft‐shelled turtle (Pelodiscus sinensis) is a commercially important species in Asian countries. Knowledge of its nutritional requirements and physiology is essential for determining the appropriate content of the feed for this animal. However, the lack of functional characterization of the intestine of this turtle limits the understanding of its absorption and utilization of nutritional materials. To solve this problem, this work utilized anatomical and histological methods to characterize 9 segments sampled along the anterior–posterior axis of the intestine. Furthermore, 9 genes, which have been well documented in the intestine division of mammals and fish, were employed to functionally characterize the 9 sampled segments. Our results suggest that regions covering from the starting site to S3 (position at 29.9% of the total length from the starting of the intestine) are the equivalent of mammalian dedumonen, and those covering S4 (40.2%) and S5 (65.4%), posterior to S8 (92.7%), are the equivalent of the mammalian ileum and the large intestine, respectively. As to the region spaning S6 (81.3%) and S7 (87.3%), its functional equivalent (small intestine or large intestine) may be variable and depends on the functional genes. This molecular characterization in relation to the division of the intestine of Chinese soft‐shelled turtle may contribute to the understanding of the nutritional physiology of the turtle, and promote Chinese soft‐shelled turtle production.     

Primary intestinal lymphangiectasia in three dogs: a morphological and immunopathological investigation

Morphological and immunological findings of three dogs with primary lymphangiectasia are described and compared with three normal dogs. Scanning electron microscopy showed distended and fused intestinal villi in dogs with intestinal lymphangiectasia, and morphometric evaluation revealed deeper crypts in the small intestine of dogs with intestinal lymphangiectasia. Although plasma cells of all classes were diminished in the cranial parts of the small intestine, there was an absolute and relative increase of immunoglobulin G-containing plasma cells in the caudal small intestine in dogs with intestinal lymphangiectasia.     

黄姑鱼肠道上皮细胞体外分离培养及鉴定

本研究旨在建立黄姑鱼(Nibea albiflora)肠道上皮细胞的体外分离培养及鉴定方法,为海水鱼类肠道功能及其发病机制相关研究提供细胞模型.以黄姑鱼肠道组织为研究对象,采用胰蛋白酶(0.25％)、胶原蛋白酶(1 mg/mL)和透明质酸酶(0.16 mg/mL)联合消化法对肠道组织进行不同时间(0、20、40、60和...     

Histology and Ultrastructure of the Gut of the Tilapia (Tilapia spp.), a Hybrid Teleost

The morphology of the intestine has been studied in a species of warm water fish, Tilapia spp., a hybrid teleost of notable economic importance. Light and electron microscope results show that the intestine is a relatively undifferentiated muscular tube lined with a simple columnar epithelium interspersed with goblet cells. The proximal region has a greater surface area, manifested by elongated mucosal ridges. The enterocytes are covered apically with uniform microvilli and exhibit the typical ultrastructural features of pinocytosis, namely extensive invaginations of the luminal plasma membrane and massive accumulation of vesicles in the apical cytoplasm. The distal intestine mucosa is thinner and less elaborately folded and consists of columnar cells with shorter and sparser microvilli. Their supranuclear cytoplasm contains abundant clear vacuoles. Numerous endocrine cells can also be seen. Regional cellular ultrastructural features are correlated with digestive functions.     

Growth and development of the digestive organs and some enzymes in broiler chicks after hatching.

1. Body weight and the weight of the digestive organs and activities of some digestive enzymes were determined from hatching to 23 d of age. 2. Relative daily growth rate peaked at 11 d of age (22% gain/d) and then decreased gradually. 3. The vitelline residue was decreased rapidly from 4.6 g at hatching to negligible values from 4 d of age. 4. Maximal allometric growth of the pancreas and small intestine was 4-fold and that of liver 2-fold greater than that of the body. 5. Activities (units/kg body weight) of the digestive enzymes measured in the pancreas and intestinal contents increased with age. In the pancreas maximal values were attained on day 8 for amylase and lipase and 11 for trypsin and chymotrypsin. In the small intestine maxima were attained on day 4 for lipase, 11 for trypsin and chymotrypsin and 17 for amylase. 6. The development of secretion of digestive enzymes in the post-hatched chick could be a limiting factor in digestion and subsequently in food intake and growth.     

The delimitation of intestine segments of koi carp (Cyprinus carpio var. koi) based on histological features

In this study, the delimitation of intestine segments of koi carp (Cyprinus carpio var. koi) was conducted using a histological approach with the measurements of height of mucosa folds (HF), width of mucosa folds (WF), thickness of muscularis (TM) and cross-sectional area (CSA). According to the change trends for these four parameters, the intestine of the koi carp was divided into anterior intestine, middle intestine and posterior intestine. The locations of the three intestine segments were defined, and their ratios along the entire intestine were accounted for 23.84 ± 1.18%, 46.77 ± 2.29% and 29.39 ± 1.65%, respectively. The anterior intestine had a significantly higher HF, compared with the middle (p < .01) or posterior intestines (p < .01). The muscularis became thin gradually from the anterior intestine to posterior part. TM was significantly different among the anterior, middle and posterior intestines (p < .01). The anterior intestine had a significantly higher CSA, compared with the middle (p < .01) and posterior intestines (p < .01), and the latter two segments had similar CSA values (p > .05). The procedure of the delimitation of the koi carp intestine segments can offer useful information for future studies on other fish species. The presented results are meaningful for studies on differential functions of the different intestine segments in fish.     

龙须菜对异育银鲫消化吸收、免疫及抗氧化性能的影响

本试验旨在评估龙须菜替代饲料中的菜粕对异育银鲫幼鱼消化吸收、免疫及抗氧化性能的影响,确定龙须菜的适宜替代范围。选取健康且规格一致的异育银鲫幼鱼450尾,随机分为6组,每组3个重复,每个重复25尾,以不含龙须菜的基础饲料为对照组饲料,以3%（D1）、6%（D2）、9%（D3）、12%（D4）、15%（D5）龙须菜替代菜粕配制成的饲料为试验饲料饲喂试验鱼8周,所有饲料等蛋等脂,试验结束时测定各组异育银鲫消化吸收、免疫及抗氧化相关酶活性。结果显示,与对照组相比,投喂龙须菜饲料各组异育银鲫肝脏消化酶活性无显著差异（P<0.05）;D1组异育银鲫前肠碱性磷酸酶、肝脏超氧化物歧化酶活性,D1和D2组异育银鲫前肠γ-谷氨酰转肽酶活性显著升高（P<0.05）,D5组异育银鲫前肠脂肪酶、碱性磷酸酶活性和肝脏超氧化物歧化酶活性显著下降（P<0.05）;D1~D3组异育银鲫肾脏酸性磷酸酶活性、D2~D5组异育银鲫血清溶菌酶活性及D2、D3组异育银鲫血清总胆固醇含量和前肠总抗氧化能力显著升高（P<0.05）,而D5组异育银鲫血清总蛋白含量显著下降（P<0.05）。综上所述,饲料中添加3%~6%的龙须菜可在一定程度上提高异育银鲫消化吸收与免疫性能,当龙须菜替代水平达15%时,会对鱼体消化吸收和健康产生负面影响。     

犊牛胰腺和小肠消化酶变化规律的研究

试验选用黑白花公犊牛21头,研究我国常规饲养管理条件下0～6月龄犊牛胰腺与小肠中主要消化酶的发育规律和变化模式。结果表明:小肠中胰蛋白酶、淀粉酶和脂肪酶活性随月龄的增长而增强,且在空肠段中酶活性均较高,6月龄分别达到11.73、914.03U/g蛋白质和423.23U/g蛋白质,乳糖酶则随月龄的增长活性降低;胰淀粉酶活性随月龄显著增长(P<0.05),0月龄胰脏内淀粉酶活性为177.19U/g蛋白质,2月龄酶活达5605.67U/g蛋白质,比0月龄增长32倍;脂肪酶活性0～1月龄间差异不显著(P>0.05),2月龄酶活显著增高(P<0.05)。由此可见各种消化酶的变化规律是不同的,它们在十二指肠、空肠和回肠的分布具有明显的区域性,空肠是营养物质消化的主要部位。     

Effects of dietary β‐(1,3)(1,6)‐D‐glucan supplementation on growth performance,intestinal morphology and haemato‐immunological profile of mirror carp (Cyprinus carpio L.)

In recent years, aquaculture research has focused on probiotics, prebiotics, and β‐glucans, in order to improve health status and growth performance. Information regarding the effects of β‐glucan on growth performance and intestinal immunity of mirror carp (Cyprinus carpio L.) is scarce. An experiment was therefore conducted to investigate the effects of a yeast β‐glucan preparation (MacroGard^®) on growth performance, intestinal morphology and haemato‐immunological indices of mirror carp. Carp (initial weight 11.1 ± 0.0 g) were fed highly purified diets supplemented with 0% (control), 0.1%, 1% or 2% MacroGard^® for 8 weeks. Fish fed diets containing 1% and 2% MacroGard^® showed significant improvements in weight gain, specific growth rate and feed conversion ratio compared to fish fed both the control and the 0.1% MacroGard^® containing diet. Histological appraisal of the intestine showed a significantly higher infiltration of leucocytes into the epithelial layer of fish fed diets supplemented with 1% and 2% MacroGard^® in the anterior intestine compared to fish fed the control and 0.1% MacroGard^® diet. This effect was not observed in the posterior intestine. There were no significant differences in the intestinal absorptive surface area and number of goblet cells in either intestinal region. At the end of the experiment, the haematological status of the fish was examined. Compared to control fed fish, the haematocrit value was significantly elevated in fish fed the 2% MacroGard^® diet. Furthermore, the blood monocyte fraction was significantly higher in fish fed the 1% and 2% MacroGard^® diets. No significant changes were observed in the other blood parameters assessed. The present study shows that high dietary β‐glucan inclusion increases growth performance without detrimental effects on the health indicators assessed. Increased intraepithelial leucocytes in the anterior intestine may indicate a localized immune response; no detrimental effects on intestinal morphology were observed.     

Digestive enzymes along digestive tract of a carnivorous fish Glyptosternum maculatum (Sisoridae,Siluriformes)

This study attempted to determine the presence, distribution and levels of digestive proteases, pepsin, amylase and lipase in the homogenates of digestive tract of a freshwater, cold‐adapted, carnivorous teleost of Tibet, Glyptosternum maculatum (n = 10, mean weight: 129.6 ± 28.9 g, mean length: 195.1 ± 16.6 mm, approximately 6 years old), at different temperatures and pH levels. The descending order of protease activity was as follows: stomach (pepsin, 16.16 ± 0.96 U/mg protein), anterior intestine (3.18 ± 0.25 U/mg protein), posterior intestine (1.76 ± 0.21 U/mg protein) and middle intestine (1.52 ± 0.23 U/mg protein). Amylase activity levels in descending order were as follows: anterior intestine (0.0062 ± 0.0007 U/mg protein), stomach (0.0032 ± 0.0009 U/mg protein), middle intestine (0.0023 ± 0.0005 U/mg protein) and posterior intestine (0.0023 ± 0.0004 U/mg protein). The highest lipase activity was found in the anterior intestine (0.83 ± 0.25 U/mg protein), followed by posterior intestine (0.51 ± 0.19 U/mg protein), middle intestine (0.48 ± 0.09 U/mg protein) and stomach (0.39 ± 0.10 U/mg protein). The optimal temperature and pH level for protease were 50 °C and 9.0–10.0, respectively, along the intestine. The pepsin optima in the stomach were 30 °C and 2.0 respectively. The optimal temperature for amylase was found to be 30 °C along the digestive tract and the optimal pH was 7.0 in the intestine and 6.0 in the stomach. The optimal temperature and pH levels of lipase were 30 °C, pH 6.0 for the stomach and 40–50 °C, pH 8.0 for the intestine, respectively. Hepato‐somatic index was 1.35 ± 0.2% and relative intestine length was 0.90 ± 0.19. The weight ratio of the stomach and intestine to body weight was 1.63 ± 0.43% and 1.57 ± 0.24% respectively.