Jejunum Of Chickens Research Articles

Intestinal epithelial responses to Salmonella enterica serovar Enteritidis: Effects on intestinal permeability and ion transport

Salmonella infection of chickens that leads to potential human foodborne salmonellosis continues to be a major concern. Chickens serve as carriers but, in contrast to humans, rarely show any clinical signs including diarrhea. The present investigations aimed to elucidate whether the absence of diarrhea during acute Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) infection may be linked to specific changes in the electrophysiological properties of the chicken gut. Immediately after slaughter, intestinal pieces of the mid-jejunum and cecum of either commercial broiler or specific pathogen-free (SPF) chickens were mounted in Ussing chambers in 2 separate experimental series. Living Salmonella Enteritidis (3 × 10(9)) or Salmonella Enteritidis endotoxin (20 mg/L), or both, were added to the mucosal side for 1 h. In both experimental series, the Salmonella infection decreased the trans-epithelial ion conductance G(t) (P < 0.05). In the jejunum of SPF chickens, there was also a marked decrease in net charge transfer across the epithelium, evidenced by decreased short-circuit current (I(sc), P < 0.05). Interestingly, the mucosal application of Salmonella endotoxin to the epithelial preparations from jejunum and cecum of SPF chicken had an effect similar to living bacteria. However, the endotoxin had no additional effect on the intestinal function in the presence of bacteria. The decreasing effect of Salmonella and or its endotoxin on G(t) could be partly reversed by serosal addition of histamine. To our knowledge, this is the first study to address the functional response of native intestinal epithelium of chicken to an in vitro Salmonella infection. For the first time, it can be reported that intestinal ion permeability of chicken decreases acutely by the presence of Salmonella. This type of response could counteract ion and fluid secretion and may thus, at least in part, explain why chickens do not develop overt diarrhea after Salmonella infection.

Effects of Se deficiency on serum histamine concentration and the expression of histamine H2 receptor in the jejunum of chickens

The present study was designed to investigate the influence of Se deficiency on serum histamine concentration and the expression of histamine receptor in the jejunum of chickens. Forty neonatal chickens were randomly divided into two groups. Experimental chickens were fed a low-Se diet (0.034 mg/kg), whereas chickens in the control group were fed a diet with a Se level of 0.229 mg/kg. Ten chickens were sacrificed on days 30, 45, 60 and 75. Blood and jejunum samples were collected. Histamine concentration in the jejunum was measured by ELISA, the jejunal mast cell (MC) ultrastructure was studied by transmission electron microscopy, and the expression level of histamine H2 receptor (H2R) mRNA in the jejunum was examined using real-time PCR. The jejunal histamine concentration in chickens fed the low-Se diet was significantly higher than that in the control group (P < 0.01). Se deficiency induced degranulation of MC in the jejunum of chickens in the low-Se diet group; their cytoplasm was filled with fused granules and vacuoles. The expression level of jejunal H2R mRNA in chickens fed the low-Se diet was also significantly higher than that in the control group (P < 0.01). The results obtained suggest that Se deficiency stimulates MC degranulation and release of histamine, binding H2R promotes both regulation of digestion and cell proliferation while protects the jejunum from injury induced by Se deficiency.

Effects of dietary protein source on the digestive enzyme activities and electrolyte composition in the small intestinal fluid of chickens

An experiment was conducted to investigate the effects of dietary protein source on the digestive enzymes and electrolyte composition of digesta fluid in the duodenum, jejunum, and ileum of chickens. A 2 × 3 factorial and completely randomized design that used 2 types of diets that differed only in their protein source [a corn-soybean meal-miscellaneous meal diet (CSMD) and a corn-miscellaneous meal diet (CMD)] and 3 types of cannulated roosters (duodenal, jejunal, and ileal cannulations) was adopted. The experiments included 5 replicates for each of the 6 treatments, and each replicate involved 3 cannulated chickens. The digesta samples were collected for 1 h every 4 h between 09:30 and 18:30 h on d 31, 33, and 35 of the experiment. The amylase, lipase, trypsin, and chymotrypsin activities and the electrolyte composition in the duodenal, jejunal, and ileal fluid were determined. In general, no significant differences between the 2 dietary groups were observed for the mean of duodenal, jejuna, and ileal amylase, trypsin, chymotrypsin, and lipase, respectively. However, the duodenal amylase activity was lower in the CMD group than the CSMD group (P < 0.05), which was probably related to the lower duodenal pH value that was observed in this group (P < 0.01). A higher jejunal Mg(2+) concentration was observed in chickens that were fed the CMD (P < 0.05), whereas the differences in the Na(+), K(+), Cl(-), and Ca(2+) concentrations in the small intestine were not significant between the 2 diets (P > 0.05). In conclusion, the digestive enzymes and electrolytes in the small intestinal fluid of chickens adapted to the protein source of the diet, and each segment of the small intestine displayed different modifications.

Effects of Acute and Chronic Cold Stress on Antioxidant Function in Intestinal Tracts of Chickens

This study was to investigate the effects of cold stress on the contents of total antioxidant capacity (T-AOC), malondialdehyde (MDA) and superoxide dismutase (SOD) in duodenum, jejunum and ileum of chickens. A total of 80 15-day-old male chickens were treated by cold stress with the duration of the acute cold stress being 1, 3, 6, 12, and 24 h, and the chronic cold stress was 5, 10, and 20 days, respectively. Cold stress temperature was (12±1)°C. The chemical colorimetric method was used to detect the changes of the T-AOC, SOD activities and MDA contents. The results showed that compared with the corresponding control group, effects of acute cold stress on the T-AOC in duodenum, jejunum and ileum of chickens significantly (P<0.05) increased firstly and then decreased. Under chronic cold stress, the T-AOC significantly (P<0.05) decreased. Under acute cold stress and chronic cold stress, the MDA contents significantly (P<0.05) increased in duodenum, jejunum and ileum of chickens. The effects of acute cold stress on the SOD activities in duodenum, jejunum and ileum of chickens significantly (P<0.05) increased firstly and then decreased. Under chronic cold stress the SOD activities significantly (P<0.05) decreased in jejunum and ileum, but significantly (P<0.05) decreased firstly and then increased in duodenum.

Localization of Ascaridia galli larvae in the jejunum of chickens 3 days post infection

The normal habitat of the parasitic stages of Ascaridia galli is in the small intestine of poultry but the exact localization is poorly understood. Therefore, a histological study was conducted in order to localize the larvae during the early phase of infection. Six layer pullets seven-week old were infected orally with 20,000 embryonated A. galli eggs each, whereas four chickens were left as un-infected controls. At necropsy 3 days after infection the first half of jejunum/ileum was divided into two equally sized sections (J1 and J2). After taking samples for histology from the middle of J1 and J2 and the junction between these determined JX, the two sections were subjected to parasitological examination. A higher number of A. galli larvae were recovered from section J2 than J1 and the majority of larvae were recovered from the most profound layers. Based on histology 144 larvae were identified and their location was noted. The highest number of larvae was observed in the JX sample as compared to J1 and J2 (P<0.001). Most of them were located in the profound crypt zone of the mucosa (51%) as compared to the other zones (P<0.05). The number of larvae was higher in the lumen (63%) compared to the epithelium (32%) and lamina propria (5%) (P<0.001). A significantly higher number of eosinophils were found in lamina propria of the infected group compared to the control group (P<0.001). This experiment clearly showed that only few larvae had penetrated the epithelium and were positioned in the lamina propria at 3 days post infection. It was far more common that the larvae were localized within the epithelium or in the lumen of the crypts. It is therefore suggested that at least in this early phase “mucosal phase” is a more appropriate term to be used for the A. galli larval localization as compared to the term “histotrophic phase” currently used in many textbooks.

Jejunal gene expression patterns correlate with severity of systemic infection in chicken

BackgroundNot much is known about the effect of Salmonella enteritidis on changes in the developmental processes occurring in the intestine of young chicken. Therefore we investigated the correlation of intestinal gene expression patterns with the severity of systemic Salmonella infections.MethodsThe number of Salmonella colony forming units (CFUs) in the liver of infected chicken were plotted against the average intestinal expression profiles of previously identified gene expression clusters. The functional properties of all the genes taken together present in 3 clusters exhibiting positive correlation at early time-points were compared with the functional properties of the genes displaying antagonistic correlations in 1 cluster. The top 5 ranking functional groups were analysed in further detail.ResultsThree clusters showed gene expression profiles which were positively correlated with the severity of systemic disease as measured by the number of Salmonella colony forming units in the liver. In these clusters, genes involved in morphological processes were predominantly present. One cluster had a profile that was negatively correlated with the severity of systemic disease, as measured by numbers of CFUs in the liver. The genes in the latter cluster were mostly involved in cell turn-over and metabolism.ConclusionsIn the developing jejunum of young chicken, both stimulatory and inhibitory gene expression mechanisms are correlated with the severity of systemic Salmonella infections.

Effect of incubation temperature on nutrient transporters and small intestine morphology of broiler chickens

This study evaluated the effects of elevated incubation temperature on posthatch nutrient transporter gene expression, integrity of the intestinal epithelium, organ development, and performance in Ross 308 broiler chickens. Ross × Ross 308 fertile eggs (n = 900) were incubated at different eggshell temperatures during development. From embryonic day (ED) 1 to ED12, all eggs were incubated at 37.1°C, whereas from ED13 to ED21, the eggs were divided into 2 groups for incubation at 37.4°C (S) or 39.6°C (H). Performance characteristics were measured at day of hatch (DOH) and d 7, 14, 21, 30, and 42. Small intestine and residual yolk sacs were collected at DOH and d 2, 4, 6, and 10 and weighed individually. Intestinal samples from the duodenum, jejunum, and ileum were evaluated for mucosal morphology and relative nutrient transporter gene expression. No significant differences were found in performance or organ weights. The intestinal morphology results showed a temperature × age interaction in duodenum villus height (P = 0.02) and crypt depth (P = 0.05) and in ileum villus height-to-crypt depth ratios (P = 0.02). There was a main effect of temperature, resulting in deeper crypts (P = 0.02) in the jejunum of chicks incubated at H compared with S. In the nutrient gene expression evaluation, peptide transporter (PepT1) showed a temperature × age interaction. On DOH and d 2, 4, and 10, PepT1 expression was similar between chicks incubated at S and H. However, on d 6, chicks incubated at S had significantly higher expression of PepT1 than those incubated at H. This study presents the effects of elevated incubation temperature on small intestine morphology and relative expression of nutrient transporter mRNA in high-yield broiler chicks, which can be important for the availability of nutrients and distribution of energy.

Expression of Toll-like receptors and antimicrobial peptides during Eimeria praecox infection in chickens

Intestinal colonization of avian species by Eimeria parasites results in the enteric disease, coccidiosis. A study was carried out to assess the immunologic effects of Eimeria praecox infection on the gut of infected chickens. In Experiment 1, birds were orally gavaged with 50,000 E. praecox oocysts; in Experiment 2, an infection dosage of 500,000 E. praecox oocysts was used. Duodenal and jejunal intestinal sections were sampled consecutively on days 1–7 post-infection. Intestinal expression of innate immune gene transcripts was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Analysis of relative gene expression in Experiment 1 revealed an increase (P<0.05) in duodenal Toll-like receptor (TLR)3 expression on days 4 and 6 post-infection. TLR15 expression was significantly decreased in the duodenum of infected birds on day 2, and significantly increased on day 6 post-infection. In Experiment 2, TLR3 was significantly downregulated in the duodenum on day 7 post-infection; however, no significant results were observed in terms of TLR15 expression. TLR4 also exhibited decreased expression (P<0.05) on day 7 post-infection in both intestinal sections. Regarding antimicrobial peptide expression; in the first experiment, expression of liver-expressed antimicrobial peptide-2 (LEAP-2) in infected birds was significantly decreased in the duodenum on days 3 and 4, and in the jejunum on day 4. Similarly, Experiment 2 resulted in depression of LEAP-2 (P<0.05) on days 3–5 in the duodenum. In Experiment 1, cathelicidin antimicrobial peptide (CATHL3) was downregulated (P<0.05) in the jejunum of infected chickens on day 3 post-infection; however, CATHL3 results were non-significant in Experiment 2. Based on the differing results observed in each experiment, it was concluded that both TLR and antimicrobial peptide expression, and thus immunity may be dependent on infection load.

Effects of feed-borne Fusarium mycotoxins and an organic mycotoxin adsorbent on immune cell dynamics in the jejunum of chickens infected with Eimeria maxima

An experiment was conducted to explore the effects of Fusarium mycotoxins, common animal feed contaminants, on intestinal immune responses to coccidia ( Eimeria) in chickens. Effects of feed-borne Fusarium mycotoxins and a polymeric glucomannan mycotoxin adsorbent (GMA) on immune cell populations were studied in the jejunum of broiler breeder pullets using an Eimeria maxima infection model. Birds were fed a control diet, a diet naturally contaminated with Fusarium mycotoxins, contaminated diet plus 0.2% GMA, or control diet plus 0.2% GMA. Contaminated diets contained up to 6.5 μg/g deoxynivalenol (DON), 0.47 μg/g 15-acetyl-DON and 0.73 μg/g zearalenone. Birds received a primary oral inoculation (1000 oocysts/bird) with E. maxima USDA strain 68 at 2 weeks of age and a secondary oral inoculation (30,000 oocysts/bird) with the same strain at 4 weeks of age. Diet-related differences in CD4 + cell, CD8 + cell and macrophage recruitment pattern into the jejunum were observed following both the primary and secondary infections. It was concluded that feed-borne Fusarium mycotoxins and GMA have the potential to modulate immune response to coccidial infections.

Successive immunoglobulin and cytokine expression in the small intestine of juvenile chicken

The intestinal mucosa is of major importance for immune development. To further study the ontogeny of avian mucosal immunity, mRNA levels of IgM, IgY and IgA, the polymeric immunoglobulin receptor (pIgR) and a number of cytokines were determined at different ages in jejunum and ileum of non-immunized healthy juvenile layer chickens. Immunoglobulin genes were successively expressed in jejunum and ileum. IgM expression was maximal in week 1, IgY expression peaked in week 5, and IgA expression was most dominant after week 7 post hatch. PIgR gene expression was relatively low in the first 2 weeks post hatch, but increased thereafter. Generally, increased expression levels of IL-1, IL-10, IL-12p40, iNOS and interferon-γ mRNA levels were found between days 14–42 as compared to days 3 and 49–70 post hatch ( p < 0.05). Correlation was found between IgA and IL-10, TGF-β and IFN-γ expression levels on days 21, 28 and 35. Cytokine mRNA expression levels decreased to basal levels between 49 and 70 days post hatch, whereas IgA reached its maximum levels in this period. Based on the current results, we hypothesize that chicken sIgA, as mammalian sIgA, may contribute to the maintenance of intestinal homeostasis.

Detection of Clostridium sp. and its Relation to Different Ages and Gastrointestinal Segments as Measured by Molecular Analysis of 16S rRNA Genes

The objective of this study was to establish a specific, sensitive and rapid PCR approach for the detection of Clostridium sp. at the genus level. Clostridium sp. in the duodenum, jejunum, ileum and cecum of broiler chickens were analyzed by 16S rRNA genes. The PCR detected the presence of Clostridium spp. in naturally contaminated intestinal samples. For the total gastrointestinal segments, 53.125, 65.625 and 59.375% samples were positive for naturally occurring Clostridium spp. at the ages 4, 14 and 30d, respectively. Analysis of the microbial contents indicated that Clostridium sp. was not consistently detected in all intestinal segments. These results can put in evidence the hypothesis that Clostridium spp. may be interfering in health and performance of chickens.

Effects of Dietary Fat Levels on Amino Acid Digestibility at Different Sites of Chicken Intestines

The present study was conducted to investigate the effects of varying dietary fat levels (3%-10%) on amino acid digestibility at different sites of fistulized chicken intestines. Chickens were fistulized to either the middle part of the jejunum (MJ), the distal end of the jejunum (DJ), the middle part of the ileum, the distal end of the ileum or the distal end of the rectum. Intestinal digesta were collected from each site of the intestine, and contents of amino acids were measured. True digestibilities of individual amino acids were not affected by the sites of intestines in the 3, 5 and 8% fat groups. The true digestibility of total amino acid in intestinal digesta at the MJ was significantly lower than that at the DJ in the 10% fat group. In addition, true digestibilities of individual amino acids at the MJ tended to be lower than those at the DJ in the 10% fat group. Comparison of the data at the MJ between groups showed that the true digestibilities of total amino acid and Met in intestinal digesta in the 10% fat group were significantly lower than those in other groups. The true digestibilities of all amino acids, except for Met, in intestinal digesta at the MJ in the 10% fat group tended to be lower than those in other groups. These results suggest that dietary fat levels influence the digestion of amino acids at the proximal part of the jejunum in chickens.

Effect of Chitosan on Nitric Oxide Content and Inducible Nitric Oxide Synthase Activity in Serum and Expression of Inducible Nitric Oxide Synthase mRNA in Small Intestine of Broiler Chickens

The present study was conducted to determine the effects of chitosan on nitric oxide (NO) content and inducible nitric oxide synthase (iNOS) activity in serum, and relative expression of iNOS mRNA in the duodenum, jejunum, and ileum of broiler chickens. A total of 240 one-day-old Arbor Acre mixed-sex broiler chickens were randomly allotted to six dietary treatments with five replicates in each treatment and eight chickens in each replicate. The broiler chickens in the six treatments were fed the basal diet supplemented with 0 (control), 0.05, 0.2, 0.5, 1.0 or 2.0 g/kg chitosan. The trial lasted for 42 days. The results showed that dietary chitosan enhanced NO content and iNOS activity in serum as well as iNOS mRNA expression in the duodenum and ileum of broiler chickens in a quadratic dose-dependent manner (p<0.05), and improved jejunum iNOS mRNA expression in a quadratic dose-dependent manner (p<0.10) with increasing addition of chitosan. Chicks fed a diet containing 0.5-1.0 g/kg chitosan had higher NO content and iNOS activity in serum as well as small-intestinal iNOS mRNA expression compared with birds given the control diet, but positive effects of chitosan tended to be suppressed when addition of chitosan in the diet was increased to 2.0 g/kg. These results implied that there was a threshold level of chitosan inclusion beyond which progressive reductions in serum NO content and small intestinal iNOS expression occured, and the regulation of chitosan on immune functions in chickens is probably associated with activated expression of iNOS and NO secretion.

Investigation on relative population of Salmonella spp. bacteria in duodenum, jejunum, ileum and cecum of poultry using densitometry technique

Salmonellosis is an infectious disease caused by Salmonella spp. that continues to plague human populations in both developed and third-world countries (Bohórquez, 2007). Conventional culture-based methods of detection that rely on enrichment of the sample and plating onto selective agar media may not be as sensitive as immunologic-or genetic-based rapid methods (Feng, 2001). PCR-based methods offer the advantages of high specificity and sensitivity. Some efforts have been made to reduce the time required and to increase the sensitivity and the accuracy of the methods to quantification of Salmonella in poultry samples (Mandrell and Wachtel 1999). This study was conducted in order to determine the relative population of Salmonella spp. in the duodenum, jejunum, ileum and caecum of chickens at different ages using densitometry.

Broyler Piliçlerin Gastrointestinal Sistemindeki Salmonella spp’nin Polimeraz Zincir Reaksiyonu ile Belirlenmesi

Summary Salmonella spp. cause a number of diseases in broiler, ultimately leading to death or to a decrease in production or condemning of carcasses. Thus, there are needed to rapid, sensitive, and reliable methods for detection of Salmonella to reduce the occurrence of salmonellosis. The objective of the present study was to establish a specific, sensitive and rapid PCR protocol for the detection of Salmonella at the genus level in Iran poultry industries. Salmonella spp. in the duodenum, jejunum, ileum and cecum of broiler chickens were compared by molecular analysis of 16S rRNA genes. Among 96 samples of gastrointestinal segments, a total of 56.25, 12.5 and 6.25% samples were positive for naturally occurring Salmonella spp. by PCR method at 4, 14 and 30d of ages respectively. For cecum, a total of 87.5, 12.5 and 12.5% samples were positive for naturally occurring Salmonella spp. by PCR method at 4, 14 and 30d of ages respectively. Analysis of the microbial contents of the different small intestine segments examined indicated that Salmonella spp. was not consistently detected in all intestinal segments. The results indicated that at 14 and 30 d of ages, Salmonella spp. was not detectable in the most of studied segments. In fact, posterior segments exhibited higher levels of Salmonella spp. compared with the anterior segments especially cecum. As demonstrated here, the development of new tools for high-throughput analyses will be of key importance for these studies. This technique is simple and rapid and can be used on different chicken samples for routine detection of a large number of samples on a daily basis..

Intestinal growth and function of broiler chicks fed sorghum based diets differing in condensed tannin levels

The effect of feeding sorghum condensed tannins on intestinal growth, function and histology was investigated in an 8-week broiler growth trial. Four sorghum varieties of different proanthocyanidins (PA) content; DC75 (DC - 2.48 A550nm/g DM) Chirimaugute (CH - 1.68 A550nm/g DM), Brown Tsweta (BT - 0.2 A550nm/g DM), SV2 (SV - 0.07 A550nm/g DM) and maize (MA) were used to formulate four diets each with one sorghum variety (CH, BT and SV) and maize included as the principal energy source. DC75 was used to replace 50 (DC50) and 100% (DC100) w/w maize to form the other two treatment diets. Relative weights of the small intestine differed significantly at 21 days of age. However, the decrease in weight did not correspond to the increase in PA level in a linear manner. Villus height and crypt depth were reduced at seven (7%) and 14 days (15%) in broilers fed DC and CH diets and thereafter was similar to MA and SV fed birds. The liver total and esterified cholesterol was reduced in DC100, DC50 and CH fed birds. Grain sorghum contains other phytochemicals such as policosanols and sterols besides PA which compound the observations in the liver. The effect of age on the severity of local liver lesions was not significant. The DC100 fed chicks showed mild crypt necrosis and/or sub-acute crypt distortion. There was a significant increase in the goblet cell number/mm2 measured in the jejunum of chicks fed CH, DC50 and DC100 diets. Sucrase but not maltase activity was significantly reduced with increased PA content in the 7-, 14- and 21-days age groups. From the results it appears that the dietary PA levels are not limiting factors in the development of the gastrointestinal tract of broiler chicks. Keywords : Sorghum; condensed tannins; intestinal adaptation; villus height; goblet cell density South African Journal of Animal Science Vol. 37 (3) 2007: pp.202-214

Adaptation of Epithelial Sodium-Dependent Phosphate Transport in Jejunum and Kidney of Hens to Variations in Dietary Phosphorus Intake

The objective of this study was to explore the homeostatic response of jejunal and renal epithelia regarding the inorganic phosphate (Pi) transport capacities to variations in dietary total phosphorus (tP) supply in hens. Adaptive processes were determined by quantitative measures of intake and excretion, Pi transport studies across brush border membranes, and semiquantitative detection of sodium-dependent phosphate transporters (NaPi II) based on mRNA expression in the jejunum and kidney. Twelve hens (4/group) were adapted to 3 tP feeding levels in a pair-fed manner (60 g/d): low P diet with 0.073% tP, medium P diet with 0.204% tP, and high P diet with 0.343% tP. Excretion was measured during the last 5 d of a 16-d feeding period. After slaughtering, jejunal mucosa and renal cortex were removed. Tissues were used for 32 P uptake studies in brush-border membrane vesicles by rapid filtration technique and NaPi II mRNA expression studies by northern analyses. Plasma Pi concentrations were additionally measured. The NaPi II transporter mRNA could specifically be detected in chicken jejunum and kidney. Functional parameters of Na+-dependent Pi transport indicated that these transporters were involved in chicken Pi transport across the apical membranes of jejunal and renal epithelia. Increased tP intake resulted in an increased overall tP excretion. Correlating individual data from all animals by linear regression highlighted that the adaptive decrease of renal Pi transport capacity and NaPi IIa mRNA expression was associated with an increase in plasma Pi levels and resulted in a higher tP excretion. Jejunal Pi transport capacity and NaPi IIb mRNA expression did not react to variations in dietary tP supply. In conclusion, the homeostatic response was mainly based on the adaptive capacity of the kidney in hens.

Influence of diet type on the inclusion of plant origin active substances on morphological and histochemical characteristics of the stomach and jejunum walls in chicken

Three hundred and thirty-six 1-day-old male Hubbard HI-Ye broiler hybrids, kept in battery cages, were fed with diets based on maize (groups I and II) or wheat and barley (groups III and IV) and supplemented with or without plant extract (XT* 100 mg/kg) containing 5% carvacrol, 3% cinnamaldehyde and 2% of capsicum oleoresin. The morphological and histochemical examinations were carried out on days 21 and 42 of bird's age. The middle part of glandular part of the stomach and 30 mm long segment from the central part of the small intestine (jejunum) were taken out and then prepared for morphometrical and histochemical assays. Mobilization of mucocytes in superficial epithelium of the glandular stomach and increased secretion of neutral mucopolysaccharides and small amounts of sialomucins with or without local cell disruption with releasing of large amounts of mucus were observed in both 'grain' groups of 21-day-old birds fed with extract. In some animals, particularly those fed mixtures with plant extract, the folds of the proventriculum mucosa were fused into large, unshaped structures. In groups fed with plant extract the mucus secretion intensity and accumulation inside cells of the gastrointestinal mucosa were slightly higher. Morphological changes on gastrointestinal mucosa observed in young chickens fed XT were reduced in older animals. The results of this study showed that the increased releasing of large amounts of mucus and the creation of a thick layer of mucus on glandular stomach and wall of jejunum in chickens fed diets with plant extract could suggest villi-related protective properties of the use of the carvacrol, cinnamaldehyde and capsaicin mixture. This can explain the reduced possibility of adhesion to epithelium and number of Escherichia coli, Clostridium perfringes and fungi in the intestinal content of bird fed with XT supplemented diet. In morphometrical parameters of depth of jejunum crypt and height of villi, the influence of kind of grain and extract supplementation was observed in 21-day-old chickens only. The significant interaction between higher jejunum wall villi layer was observed only in chickens fed on maize diet supplemented with plant extract.

Heat stress increases apical glucose transport in the chicken jejunum

In chickens, elevated environmental temperature reduces food intake. We have previously reported that, during heat stress, the intestinal mucosa has an increased capacity to take up sugars. To investigate whether the effects of warm environment on sugar uptake are an intestinal adaptation to lower energy intake or a response attributable to heat stress, we examined the glucose transport kinetics of apical and basolateral membranes of the jejunum and the mucosal morphology of broiler chickens maintained in climatic chambers for 2 wk. Experimental groups were 1) control ad libitum (CAL), fed ad libitum and in thermoneutral conditions (20 degrees C); 2) heat stress ad libitum (HSAL), fed ad libitum and kept in a heated environment (30 degrees C); and 3) control pair-fed (CPF), maintained in thermoneutral conditions and fed the same amount of food as that consumed by the HSAL group. Both the CPF and the HSAL groups showed reduced body weight gain, but only the HSAL chickens had lower plasma thyroid hormones and higher corticosterone than CAL and CPF groups. The fresh weight and length of the jejunum were only reduced in the HSAL group. The activity and expression of apical sodium-dependent glucose transporter 1 (SGLT-1) were increased by approximately 50% in the HSAL chickens, without effects in the CPF group. No changes in K(d) or in SGLT-1 and glucose transporter-2 K(m) were observed in the pair-fed and heated birds. These results support the view that increased intestinal hexose transport capacity is entirely dependent on adaptations of apical SGLT-1 expression to heat stress and is not due to reduced food intake.

Changes in chicken intestinal zinc exporter mRNA expression and small intestinal functionality following intra-amniotic zinc-methionine administration

A 303-bp cDNA of intestinal zinc exporter (ZnT1) was isolated from chicken jejunum by reverse transcriptase-polymerase chain reaction and sequenced, and showed 42% homology to Homo sapiens and Rattus novergicus intestinal ZnT1 genes. This specific probe was used to examine the effect of zinc-methionine (ZnMet) administration on the mRNA expression of ZnT1 and on small intestinal development and functionality. In this study, ZnMet was injected into the naturally consumed amniotic fluid of 17-day-old chicken embryos. The ZnT1 gene showed an approximately 200% increase in its mRNA levels from 48 h post-ZnMet injection, as compared to the control. An analysis of the gene expression of the brush-border enzymes and transporters showed increased mRNA expression of sucrase isomaltase, leucine-aminopeptidase, sodium-glucose cotransporter and Na +K +ATPase transporter (Na +K +ATPase) from 48 h post-ZnMet injection, in comparison to controls. Significant increases ( P<.05) in the biochemical activity of the brush-border enzymes and transporters, and in jejunal villus surface area were detected from day of hatch (96 h post-ZnMet injection) as compared to controls. These results suggest that ZnMet administration into prenatal intestine via injection into the amniotic fluid enhances intestinal development and improves its functionality.