Lymphoid cells in chicken intestinal epithelium

Moderate zinc restriction affects intestinal health and immune function in lipopolysaccharide-challenged mice

Zinc (Zn) is an essential nutrient that affects immune function, especially within the digestive system, although the underlying mechanisms are not well understood. This study examined the effects of short-term moderate Zn restriction on intestinal health and immune function in lipopolysaccharide (LPS)-challenged mice through plasma cytokine profiling and histological evaluation of intestinal tissue sections. Adult male mice were fed with a Zn-adequate (40 ppm) or a Zn-marginal (4 ppm) diet for 4 weeks, and then a bacterial challenge was simulated by intraperitoneal injection of LPS (10 microg/g body weight [BW]) or saline (control). BW was recorded weekly, and feed intake was recorded daily over the last week. Voluntary locomotor activity was assessed 6 and 24 h after the challenge. Plasma and tissues were collected 0, 6 or 24 h after the challenge for analysis. Histological analysis of intestinal samples included evaluation of villi length and width, lamina propria (LP) width, crypt depth and intraepithelial as well as LP leukocyte numbers. Plasma was analyzed for IL-1beta, IL-4, IL-6, IL-10, IL-12p40, IL-12p70, interferon gamma and tumor necrosis factor alpha. Diet did not affect BW and feed intake. The LPS challenge led to decreased voluntary locomotor activity (P<.05). Moderate Zn restriction led to greater leukocyte infiltration in the LP after the LPS challenge (P<.05) and higher plasma IL-6 and IL-10 levels 24 h after the LPS challenge (P<.01). Results indicate that Zn status impacts intestinal responses to LPS through modulation of the cytokine response and leukocyte recruitment, and this impact is evident even with short-term (4 weeks) moderate Zn restriction.

Turkey breeder hen age affects growth and systemic and intestinal inflammatory responses in female poults examined at different ages posthatch

This trial examined the effect of 2 turkey breeder hen ages (33 or 55 wk of age) on performance, intestinal histology, and inflammatory immune response of female turkey poults grown to market weight. Using a randomized design, female poults were separated by breeder flock age (n = 8 floor pens/breeder flock age; n = 26 poults/pen; 0.195 m(2)/bird), fed identical commercial diets (9 phases), and grown to market weight (approximately 11.4 kg/ bird). At young ages, poults from the older breeder flock tended to have higher BW (P < 0.01 for d 7, P < 0.09 for d 63), although feed consumed was not significantly different due to breeder flock age (P > 0.20 for all ages). After approximately 63 d posthatch, no difference in BW was observed, suggesting that poults from the younger breeder flock were eventually able to compensate for initial reductions in performance. In addition to growth measurements on d 10, 24, and 65 posthatch, poults were vaccinated with lipopolysaccharide (LPS, from Salmonella Typhimurium; 0.5 mg/kg of BW intraabdominally) or not vaccinated (control), and intestinal histology and plasma haptoglobin were assessed at 24 h postadministration. In control birds, intestinal villus length was greater for poults from the older breeder flock (P < 0.05), as was crypt depth (P < 0.05 for d 11 and 25). Plasma haptoglobin levels did not change in 11-d-old poults after LPS administration, but they increased with LPS at d 25 and 66 posthatch (P < 0.05 for each). At d 66 posthatch, poults from the younger flock had increased haptoglobin levels post-LPS compared with those from the older breeder flock (P < 0.05). In general, LPS administration increased villus width in the jejunum and ileum (P < 0.05 for each), increased lamina propria width in the duodenum and ileum (P < 0.05 for each), and decreased ileum crypt depth (P < 0.05). Overall, poults from the older breeder flock had reduced inflammatory responses, even at 9 to 10 wk posthatch, even though performance was similar in poults from the 2 flocks by this age.

Effects of Copper Source and Level on Intestinal Physiology and Growth of Broiler Chickens

Dietary copper sulfate (CuSO4) and tribasic copper chloride (TBCC) were examined for their effects on intestinal physiology and growth of broiler chickens. In 2 experiments (Experiments 1 and 2), day-old broiler chicks were fed 1 of 4 diets: a basal diet with no supplemental copper (Cu; negative control), a basal diet + 188 mg of Cu/kg of diet from TBCC or CuSO4, or a basal diet + subtherapeutic antibiotics (bacitracin and roxarsone; positive control). In Experiment 1 (recycled litter), CuSO4 and TBCC increased carcass weight (d 45 posthatch) compared with the negative control (P < 0.05 for each). In Experiment 2 (fresh litter), negative control and TBCC increased carcass weight (d 42 posthatch) compared with the positive control (P < 0.05 for each). At d 30 to 31 posthatch, intestinal histology was measured. In Experiment 1 (recycled litter), dietary TBCC, CuSO4, and positive control decreased the number of lamina propia lymphocytes or intraepithelial lymphocytes (IEL), or both, compared with the negative control (P < 0.05). However, in Experiment 2 (fresh litter), TBCC and positive control increased the number of duodenum IEL compared with the negative control (P < 0.05), and negative control and TBCC increased the number of ileum IEL. These data demonstrate that broiler performance and intestinal physiology can be influenced by dietary Cu source and level as well as microbial environment (fresh vs. recycled litter).

Intestinal immune responses to coccidiosis

Intestinal parasitism is a major stress factor leading to malnutrition and lowered performance and production efficiency of livestock and poultry. Coccidiosis is an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria. Infection with coccidia parasites seriously impairs the growth and feed utilization of chickens and costs the US poultry industry more than $1.5 billion in annual losses. Although acquired immunity to Eimeria develops following natural infection, due to the complex life cycle and intricate host immune response to Eimeria, vaccine development has been difficult and a better understanding of the basic immunobiology of pertinent host-parasite interactions is necessary for developing effective immunological control strategies against coccidiosis. Chickens infected with Eimeria produce parasite specific antibodies in both the circulation and mucosal secretions but humoral immunity plays only a minor role in protection against this disease. Rather, recent evidence implicates cell-mediated immunity as the major factor conferring resistance to coccidiosis. This review will summarize current understanding of the avian intestinal immune system and its response to Eimeria as well as provide a conceptual overview of the complex molecular and cellular events involved in intestinal immunity to coccidiosis. It is anticipated that increased knowledge of the interaction between parasites and host immunity will stimulate the birth of novel immunological and molecular biological concepts in the control of intestinal parasitism.

Characterization of distal lymphoid nodules in the chicken caecum

In this report, we describe lymphoid nodules consistently found in the distal region of each chicken caecum at approximately 3 cm from the ileo-cecal junction. These structures were studied by light microscopy both in normal and Eimeria tenella-infected chickens. They were observed with the naked eye in infected birds but not in normal chickens. In these latter the region of the caecal lamina propria corresponding to that in which the lymphoid aggregates were visible revealed a light infiltration by diffuse lymphoid tissue as well as a few germinal centers. The distal lymphoid nodules were studied using a panel of monoclonal antibodies which are specific for chicken Ig-containing cells, macrophages, Ia-like positive cells, and interdigitating cells, as well as a policlonal antiserum reactive with S-100 protein to stain both interdigitating cells and follicular dendritic cells. The immunohistochemical study demonstrated the resemblance of these aggregates to the caecal tonsils, suggesting that they represent specialized mucosa-associated lymphoid tissue that respond to antigens in the caecal lumen, their function being to enhance the mucosal defense provided by the caecal tonsils against antigens in the lumen of the caeca.

Lymphocytes of the intestinal mucosa of chickens

Examination, by light and electron microscopy, of the morphology and the staining properties of intraepithelial lymphocytes from the intestine of the chicken revealed a population of lymphoid cells, of which a proportion (up to 20%) is granulated. The majority of cells were immunoreactive with anti-T cell serum and can therefore be considered to be related to T-lymphocytes, but they did not proliferate when cultured with phytohaemagglutinin. The granulated cells were identical to those previously designated globule-containing leukocytes, but were distinct from mast cells in their morphology, staining reactions and the stability of the granules in different fixatives and buffers.

Quantification of intraepithelial lymphocytes in the turkey uterovaginal junction

Intraepithelial lymphocytes (IEL) were quantified in the uterovaginal junction (UVJ) and sperm-storage tubule (SST) epithelia in virgin hens 22 wk and inseminated hens 2 to 4, 10, and 22 wk after the onset of photostimulation. The UVJ epithelium of virgin and all inseminated hens possessed about 1 to 2 IEL/100 luminal epithelial cells. There were no significant interactions between hen fertility 22 wk postphotostimulation and the percentage of IEL in the UVJ or SST epithelia nor did the presence or absence of luminal sperm influence the percentage of IEL in the SST of inseminated hens. However, the percentage of IEL in the SST (with or without luminal sperm) was significantly higher 22 wk postphotostimulation than in the similar tissue at 2 to 4 and 10 wk. It is suggested that IEL at the SST may act to sequester sperm antigens or represent an autoimmune response to some factor(s) associated with the SST.

Ultrastructure of gut-associated lymphoid tissue (GALT) in the amphibian urodele, Pleurodeles waltlii

The ultrastructure of gut-associated lymphoid tissue (GALT) has been studied in the salamander, Pleurodeles waltlii. Lymphoid accumulations appear as true infiltrates scattered throughout the lamina propria cell elements. The most important components of these infiltrates are small and medium sized lymphocytes, and, in lesser amounts, developing and mature plasma cells, macrophages and granulocytes. Migrating lymphoid cells massively invade the intestinal epithelium inducing noticeable modifications, such as the disappearance of the basement membrane and decreased numbers of mucous cells. Thus, in its organization and cell composition, the GALT of P. waltlii appears to represent a primitive phylogenetic precursor of the mammalian "intestinal-immunologic" barrier.

The ultrastructure of the normal conjunctival epithelium of the guinea pig. III. The bulbar zone, the zone of the fornix and the supranodular zone

Three adjacent zones of the conjunctival epithelium of the guinea pig are described: the three-layered bulbar zone with cuboidal superficial cells, the three-layered zone of the fornix with cylindrical superficial cells, and the four- to five-layered supranodular zone characterized by close association with a lymphoid nodule. The similarities and differences in the general morphology of the epithelium and in the ultrastructural features of the cells, as compared to those of the perilimbal zone, are pointed out. The functional significance of atypical mitochondria found in certain cells of the bulbar and fornical zones is commented upon. Particular attention is paid to the supranodular zone, containing a large number of intraepithelially located lymphocytes. The possible role of an epithelium associated with subepithelial lymphoid tissue in the immune defense is discussed.

Organ culture of adult mouse intestine. I. Morphological results after 24 and 48 hours of culture

Explants of adult mouse intestine have been maintained in organ culture for 24 to 48 hr. The best results have been obtained with a mixture of DMEM-HEPES medium and NCTC-135 enriched with 10% fetal bovine serum. The morphology of the mucosa is well preserved at the light and electron microscopic level: absorbing cells exhibit an increase in secondary lysosomes; goblet cells and Paneth cells remain active; numerous mitoses are observed in the crypts; and vigorous re-epithelization takes place on the margin of the explants.