Effect of platelet-activating factor on food intake, cloacal temperature, voluntary activity and crop emptying rate in chicks.

Platelet-activating factor (PAF) plays a significant role in several leucocyte functions, including platelet aggregation and inflammation. Additionally, PAF has a role in the behavioral and physiological changes in mammals. However, the effect of PAF has not been well studied in birds. Therefore, the study aimed to determine if PAF affects feeding behavior, voluntary activity, cloacal temperature, and feed passage through the digestive tract in chicks (Gallus gallus). We also studied the involvement of PAF in the innate immune system induced by lipopolysaccharide (LPS), a cell wall component of gram-negative bacteria. Both intraperitoneal (IP) and intracerebroventricular (ICV) injections of PAF significantly decreased food intake. IP injection of PAF significantly decreased voluntary activity and slowed the feed passage from the crop, whereas ICV injection had no effect. Conversely, ICV injection of PAF significantly increased the cloacal temperature, but IP injection had no effect. The IP injection of LPS significantly reduced the mRNA expression of lysophosphatidylcholine acyltransferase 2, an enzyme responsible for PAF production in the heart and pancreas. On the other hand, LPS significantly increased the mRNA expression of the PAF receptor in the peripheral organs. The present study shows that PAF influences behavioral and physiological responses and is related to the response against bacterial infections in chicks.

Role of nitric oxide on zymosan-induced inhibition of crop emptying in chicks.

Zymosan, a component of yeast cell walls, reduces feed passage through the digestive tract in chicks (Gallus gallus), although the mechanism mediating this effect is poorly understood. Nitric oxide (NO) is associated with a variety of biological actions including effects on the immune system. In addition, it has been suggested that NO is involved in relaxation of the digestive tract and affects feed passage in mammals. It is therefore possible that NO might be related to zymosan-induced reduction of feed passage in chicks. However, the role of NO on the effect of zymosan feed passage has not been clarified yet. Thus, the purpose of the present study was to investigate whether NO is associated with zymosan-induced alteration of feed passage in chicks. Intraperitoneal (IP) injection of zymosan significantly increased plasma nitrate and nitrite (NOx) concentrations at 6 h after injection. Zymosan-induced elevation of plasma NOx concentration was abolished by co-injection of S-methylisothiourea (SMT), a selective inhibitor for inducible NO synthase (iNOS), indicating that zymosan facilitated the induction of iNOS. Furthermore, because zymosan increased iNOS mRNA expression in the digestive tract, NO is likely associated with the effect of zymosan on the digestive tract. IP injection of NO donors significantly decreased crop emptying rate, suggesting that NO functions as an inhibitor of crop emptying. This result implied that zymosan stimulates NO production by the induction of iNOS in the digestive tract and thereby inhibits crop emptying rate. However, the co-injection of SMT did not attenuate the inhibitory effect of zymosan on crop emptying. The present study provides evidence that some changes in the digestive tract caused by zymosan are mediated by iNOS-induced NO in chicks, but NO does not mediate the effect of zymosan on feed passage through the crop.

Targeted disruption of TORC1 retards young squab growth by inhibiting the synthesis of crop milk protein in breeding pigeon (Columba livia).

This study was conducted to explore the regulatory role of the target of rapamycin complex 1 (TORC1) signaling pathway in crop milk synthesis in breeding pigeons (Columba livia). Three groups of breeding pigeons in the lactation period (n = 30 pairs/group) were respectively injected with rapamycin (RAPA, a specific inhibitor of the target of rapamycin complex) at doses of 0 (vehicle, control), 0.6, or 1.2 mg/kg body weight (BW)/day via the wing vein for 7 days. The average daily feed intake (ADFI) and BW of the breeding pigeons and the BW of young squabs were respectively recorded throughout the experimental period. The breeding pigeons were sacrificed to collect their crop tissues, crop milk, and serum on the eighth day of the experiment. The results showed that neither 0.6 nor 1.2 mg/kg BW RAPA injection affected BW loss or ADFI in breeding pigeons (P > 0.05), while crop thickness and crop relative weight were significantly decreased (P < 0.05) in the 1.2 mg/kg BW rapamycin-injected group. Simultaneously, RAPA (especially at 1.2 mg/kg BW) decreased the crude protein, αs1-casein, αs2-casein, ß-casein, and amino acid contents (Asp, Thr, Ser, Glu, Gly, Ala, Cys, Val, Met, Ile, Leu, Tyr, Lys, His, Arg, and Pro) of crop milk (P < 0.05) and the concentrations of albumin, total protein, and uric acid in the serum of breeding pigeons (P < 0.05). Additionally, the expression of TORC1 pathway-related proteins (TORC1, S6K1, S6, 4EBP1, and eIF4E) was downregulated in the crop tissues of breeding pigeons by 0.6 or 1.2 mg/kg BW/day RAPA injection (P < 0.05). Accordingly, the average daily gain (ADG) of young squabs declined, and the mortality rate increased significantly (P < 0.05). Together, the results showed that RAPA reduced protein and amino acid levels in the crop milk of breeding pigeons and retarded young squab growth, suggesting a crucial role of TORC1 in crop milk synthesis in breeding pigeons.

Prolactin induces lipid synthesis of organ-cultured pigeon crops.

The objective of this research was to examine the effects of prolactin (PRL) on the lipid synthesis of organ-cultured pigeon crops in vitro. In experiment 1, the histology, activities of enzymes, and expression of genes involved in metabolism and apoptosis of organ-cultured pigeon crops were analyzed over a 7-d culture period. The results showed that cultured crops maintained their structural integrity for up to 3 d in vitro. Beyond 3 d, caspase-3 activity and Bak1 gene expression increased with day of culture, whereas the activities of succinate dehydrogenase, Na+-K+-ATPase, Ca2+-Mg2+-ATPase, total ATPase, and gene expression of Bcl-2 and CK-19 diminished (P < 0.05). In experiment 2, the crops were cultured for 24, 36, and 48 h in medium containing 0, 25, or 50 ng/mL PRL, respectively, and the accumulation of lipid droplets, lipid content, and expression of fatty acid transportation- and lipogenesis-related genes were analyzed. The results showed that the crops with PRL supplements showed higher amounts of lipid droplets than those of the controls, and the droplets were mainly located in the basal nutritive layer in response to PRL. The efficacy of inducing lipid accumulation increased as the concentration of PRL increased. Crops with 50 ng/mL PRL incubated for 36 h displayed the maximal lipid content. Increasing the concentration of PRL from 0 to 50 ng/mL resulted in a dose-dependent increase in the expression of acetyl-CoA carboxylase, fatty acid synthase, fatty acid translocase, fatty acid binding protein 5, acyl-CoA binding protein, and peroxisome proliferator-activated receptor γ genes after incubation for 36 h (P < 0.05). Therefore, our results indicated that the organ-cultured pigeon crops maintained good viability for up to 3 d in vitro. Furthermore, PRL induced the lipid synthesis of organ-cultured pigeon crops in a dose- and time-dependent manner, which was related to the increased expression of genes involved in fatty acid transportation and lipogenesis.

Changes in hormone profiles, growth factors, and mRNA expression of the related receptors in crop tissue, relative organ weight, and serum biochemical parameters in the domestic pigeon (Columba livia) during incubation and chick-rearing periods under artificial farming conditions.

The present study was conducted to determine the changes in concentrations of hormones and growth factors and their related receptor gene expressions in crop tissue, relative organ weight, and serum biochemical parameters in male and female pigeons during incubation and chick-rearing periods under artificial farming conditions. Seventy-eight pairs of 60-week-old White King pigeons with 2 fertile eggs per pair were randomly divided into 13 groups by different breeding stages. Serum prolactin and insulin-like growth factor-1 (IGF-1) concentrations in crop tissue homogenates were the highest in both male and female pigeons at 1 d of chick-rearing (R1), while epidermal growth factor (EGF) in female pigeons peaked at d 17 of incubation (I17) (P < 0.05). mRNA expression of the prolactin and EGF receptors in the crop tissue increased at the end of incubation and the early chick-rearing stage in both sexes. However, estrogen, progesterone, and growth hormone receptor expression each decreased during the early chick-rearing stage (P < 0.05). In male pigeons, IGF-1 receptor gene expression reached its peak at R7, while in female pigeons, it increased at the end of incubation. The relative weight of breast and abdominal fat in both sexes and thighs in the males was lowest at R7, and then gradually increased to the incubation period level. Serum total protein, albumin, and globulin concentrations increased to the highest levels at I17 (P < 0.05). Total cholesterol, triglyceride, and low-density lipoprotein reached their highest values at I17 in male pigeons and R25 in female pigeons (P < 0.05). In conclusion, hormones, growth factors, and their receptors potentially underlie pigeon crop tissue development. Changes in organs and serum biochemical profiles suggested their different breeding-cycle patterns with sexual effects.

Gene expression of amino acid transporter in pigeon (Columbia livia) intestine during post-hatch development and its correlation with amino acid in pigeon milk.

This study was conducted to evaluate gene expression of the amino acid transporter in post-hatch pigeon small intestine and the association of pigeon milk amino acid with the above transporter's gene expression. A total of 48 pigeon breeding families were randomly allocated to 8 groups of 6 replicates of one parental pigeon pair and 2 squabs. Samples of pigeon milk and duodenum, jejunum, and ileum were collected on d 1, 2, 3, 4, 6, 8, 10, and 14 post hatch. The results showed that levels of crude protein (8.93 to 15.56%) were highest in pigeon milk on an air-dry basis. Amino acid content in pigeon milk remained constant in the first 4 d, declined abruptly at d 6, then increased dramatically from d 8 to 14. There was a significant effect of interaction between age and intestinal segments on those amino acid transporters gene expression. mRNA abundance of ATB0'+, SNAT-2, LAT-4, rBAT, b0'+AT, EAAT-3 and PAT-1 was highest in the ileum; B0AT1, asc-1, and IMINO were predominate in the jejunum; and CAT-1 and y+LAT2 were greatest in the duodenum. Age-related changes of amino acid transporter mRNA was inconsistent. mRNA levels of SNAT-2, rBAT, y+LAT2, b0'+AT, and EAAT-3 ascended with age, whereas that of asc-1, CAT-1, and IMINO diminished significantly. Levels of B0AT1 and PAT-1 mRNA abundance were minimized at d 6. However, few correlations were found between pigeon milk amino acid and the amino acid transporter gene expressions in squab small intestine. Our findings provide a comprehensive elaboration on ontogeny of the amino acid transporter in post-hatch pigeon intestine.

Lipopolysaccharide reduces food passage rate from the crop by a prostaglandin-independent mechanism in chickens.

1. We examined the effect of lipopolysaccharide (LPS), a component of Gram-negative bacteria, on food passage in the digestive tract of chickens (Gallus gallus) in order to clarify whether bacterial infection affects food passage in birds. 2. Food passage in the crop was significantly reduced by intraperitoneal (IP) injection of LPS while it did not affect the number of defecations, suggesting that LPS may affect food passage only in the upper digestive tract. 3. Similar to LPS, prostaglandin E2 (PGE2), one of the mediators of LPS, also reduced crop-emptying rate in chickens while it had no effect on the number of defecations. 4. Pretreatment with indomethacin, which is an inhibitor of cyclooxygenase (COX), a prostaglandin synthase, had no effect on LPS-induced inhibition of crop emptying. 5. IP injection of LPS did not affect the mRNA expression of COX2 in the upper digestive tract of chickens. 6. It is therefore likely that LPS and PGE2 reduced food passage rate in the crop by a prostaglandin-independent pathway in chickens.

Crop milk protein is synthesised following activation of the IRS1/Akt/TOR signalling pathway in the domestic pigeon (Columba livia).

The experiment was conducted to study whether insulin receptor substance 1 (IRS1) / Protein kinase B (Akt)/target of the rapamycin (TOR) signalling pathway activation stimulates crop milk protein synthesis in the domestic pigeon (Columba livia). Crop milk was collected from ten 1-d-old squabs and analysed for nutrient content. During the non-breeding period and the first day of lactation, blood samples were collected from 5 pairs of breeding pigeons and the levels of prolactin and insulin were determined. Crop samples were collected from 5 pairs of breeders at d 14 and 16 of the incubation period and d 1, 3 and 7 of the lactation period. Crop samples were evaluated for changes in crop weight and thickness and changes in the expression patterns of IRS1/Akt/TOR signalling pathway-related proteins. The results demonstrated that prolactin induces a gradual increase in the relative weight and thickness of the crop, with crops reaching a maximum size at the third day of lactation. Pigeon crop milk contains 64.1% crude protein and 29.7% crude fat based on dry weight. Serum prolactin and insulin levels in the lactation period were significantly higher than those in the non-breeding period. Compared with non-breeding pigeons, the expression of the phosphorylated IRS1 phosphorylated Akt, phosphorylated TOR, phosphorylated ribosomal protein S6 kinase, phosphorylated S6, phosphorylated eukaryotic initiation factor 4E binding protein 1 and eukaryotic initiation factor 4E were significantly up-regulated in the crop of pigeons in the lactation period. In conclusion, prolactin might induce changes in crop tissue and form the physiological structure for crop milk synthesis. Furthermore, the synthesis of crop milk protein is regulated by activation of the IRS1/Akt/TOR signalling pathway.

Nutritional quality and amino acid composition of diets consumed by scavenging hens and cocks across seasons.

The objective of the study was to determine the effect of season on nutritional quality and amino acid composition of diets that scavenging hens and cocks consume. Thirty hens and 30 cocks were purchased and slaughtered during each of the rainy, post rainy, cool dry and hot dry seasons. A total of 240 birds were used in the study. Fresh crop content weights were high (P < 0.05) during the cool dry season. Cereal grains, kitchen wastes, green materials, animal protein sources and inorganic materials were the main components of the crop contents. Crop contents varied with season and sex of bird (P < 0.05). The cereal grain weights were high during cool dry and hot dry seasons. Weights of animal protein sources (insects, locusts and termites) were higher (P < 0.05) during the rainy and post rainy seasons. Hens contained more animal protein sources (P < 0.05) than cocks. Hens had a higher (P < 0.05) lysine content during the rainy season than cocks. Histidine, serine, arginine, threonine, cysteine and lysine contents varied with seasons (P < 0.05). Methionine did not vary with season and sex of the bird. Nutritional supplementation of village chickens should, therefore, vary with seasons.

Dietary effects on inositol phosphate breakdown in the crop of broilers.

The effect of diets differing in enzyme supplements, mineral phosphorus (P) and microwave wheat treatment on phytate hydrolysis and lower inositol phosphate isomers (InsPs) appearance in broiler crops was studied. The broilers (16- and 15-day-old) were assigned to 48 pens of 15 or 20 birds each (n = 8 pens per treatment) in Experiments 1 and 2, respectively. In Experiment 1, birds received a low-P wheat-soybean meal diet where the wheat was either microwave treated or not. These diets were offered without further supplementation or with added phytase (500 FTU/kg diet), alone or in combination with a xylanase (16,000 BXU/kg diet). In Experiment 2, two maize-soybean meal-based diets were fed, without or with monocalcium phosphate supplementation. Furthermore, these diets were offered without further supplementation or with phytase at 500 or 12,500 FTU/kg diet. On day 23 or 24 (Experiments 1 and 2, respectively), crop digesta were pooled per pen, freeze-dried and analysed for InsPs and the marker TiO2. Microwaving reduced the intrinsic phytase activity and InsP6 hydrolysis, but increased the concentration of Ins(1,2,3,4,5)P5 and Ins(1,2,4,5,6)P5 in the digesta of crop (Experiment 1). Microwave treatment significantly interacted with enzyme supplementation for Ins(1,2,5,6)P4 concentration, indicating a synergistic effect of intrinsic and supplied phytase in the crop. Xylanase tended to support phytase hydrolysis in diets with microwave-treated wheat. Phytase addition increased InsP6 hydrolysis up to 79% (Experiment 2). Thus, wheat phytase activity can cause high InsP6 hydrolysis in the crop. Treatment differences in lower InsPs indicated that hydrolysis of the first InsP6 phosphate group is not the only step in the degradation cascade in the crop of broilers that is influenced by dietary factors.

Single-dose toxicokinetics of permethrin in broiler chickens.

Single-dose toxicokinetics of permethrin was investigated in broiler chickens. A total of 20 male broiler chickens were assigned at random to two groups of 10 at 30 days of age. A single dose of 10 mg/kg body weight of permethrin was administered intravenously to the first group; in the second group, the same dose was administered into the crop. Serum permethrin was measured using an electron capture detector and gas chromatography equipment. The derived serum permethrin concentration/time curve demonstrated that the distribution kinetics of permethrin was well described by a two-compartment open model. For intravenous permethrin administration, the half-life at λ phase (t1/2λ), mean residence time (MRT) and area under the concentration-time curve in 0→∞ (AUC0→∞) values respectively were 4.73 ± 1.00 h, 5.06 ± 1.05 h and 16.45 ± 3.28 mg/h/l. In contrast, the Cmax, tmax, t1/2λ, MRT and AUC0→∞ values respectively of the group given intra-crop permethrin were 0.60 ± 0.42 µg/ml, 0.55 ± 0.19 h, 5.54 ± 0.78 h, 7.06 ± 0.63 h and 1.95 ± 0.97 mg/h/l. The bioavailability of permethrin was 0.11. For both administration routes, the residence time of permethrin in the body was short and the bioavailability of permethrin was low. These results are relevant for assessing the use and safety of permethrin.

Differential gene expression profiles of ß-defensins in the crop, intestine, and spleen using a necrotic enteritis model in 2 commercial broiler chicken lines.

Changes in the expression levels of avian ß-defensin (AvBD) mRNA were evaluated in necrotic enteritis (NE) disease model in 2 genetically disparate commercial broiler chicken lines: Ross and Cobb. The NE was initiated in the gut by a previously established co-infection model using oral Eimeria maxima infection followed by a Clostridium perfringens challenge. Among the 14 AvBD types examined, there was a tissue-specific expression of AvBD transcripts: AvBD1, AvBD7, and AvBD9 in the crop; AvBD8, AvBD10, and AvBD13; in the intestine and AvBD1 and AvBD7 in the spleen. The 2 different commercial broiler chicken lines showed differential gene expression patterns of AvBD transcripts following co-infection with E. maxima and C. perfringens, with R-line chickens generally showing higher expression levels than the C strain. Both chicken strains showed enhanced gene expression levels of proinflammatory cytokines, such as IL-1ß, IL-6, IL-17F, and TNFSF15 in spleen, and TNFSF15 in intestine, whereas IL-17F was significantly increased only in the intestine of R-line chickens following NE infection. Although the exact nature of interactions between defensins and cytokines in determining the outcome of host innate immune responses to the pathogens of NE remains to be investigated, the differences in gene expression levels of ß-defensins and proinflammatory cytokines in the intestine, crop, and spleen could explain the predisposed disease resistance and susceptibility to NE in the 2 commercial broiler chicken lines.

Histological and global gene expression analysis of the 'lactating' pigeon crop.

BACKGROUND: Both male and female pigeons have the ability to produce a nutrient solution in their crop for the nourishment of their young. The production of the nutrient solution has been likened to lactation in mammals, and hence the product has been called pigeon 'milk'. It has been shown that pigeon 'milk' is essential for growth and development of the pigeon squab, and without it they fail to thrive. Studies have investigated the nutritional value of pigeon 'milk' but very little else is known about what it is or how it is produced. This study aimed to gain insight into the process by studying gene expression in the 'lactating' crop. RESULTS: Macroscopic comparison of 'lactating' and non-'lactating' crop reveals that the 'lactating' crop is enlarged and thickened with two very obvious lateral lobes that contain discrete rice-shaped pellets of pigeon 'milk'. This was characterised histologically by an increase in the number and depth of rete pegs extending from the basal layer of the epithelium to the lamina propria, and extensive proliferation and folding of the germinal layer into the superficial epithelium. A global gene expression profile comparison between 'lactating' crop and non-'lactating' crop showed that 542 genes are up-regulated in the 'lactating' crop, and 639 genes are down-regulated. Pathway analysis revealed that genes up-regulated in 'lactating' crop were involved in the proliferation of melanocytes, extracellular matrix-receptor interaction, the adherens junction and the wingless (wnt) signalling pathway. Gene ontology analysis showed that antioxidant response and microtubule transport were enriched in 'lactating' crop. CONCLUSIONS: There is a hyperplastic response in the pigeon crop epithelium during 'lactation' that leads to localised cellular stress and expression of antioxidant protein-encoding genes. The differentiated, cornified cells that form the pigeon 'milk' are of keratinocyte lineage and contain triglycerides that are likely endocytosed as very low density lipoprotein (VLDL) and repackaged as triglyceride in vesicles that are transported intracellularly by microtubules. This mechanism is an interesting example of the evolution of a system with analogies to mammalian lactation, as pigeon 'milk' fulfils a similar function to mammalian milk, but is produced by a different mechanism.

Assessment of the nutritional status of indigenous scavenging chickens in Ada'a district, Ethiopia.

The nutritive values of scavenging feed resource bases and effects of season and chickens age on the latter were studied in smallholder farms in Aad'a, Ethiopia. The study included 210 households and 208 chickens. The mean weight of crop contents in all age groups ranged from 26.2 to 28.2 g, while it was 29.8 g and 24.7 g in the harvesting and non-harvesting seasons, respectively. Grains represented 48-49% of the mean weight of crop contents in all age groups and it was significantly higher (P < 0.05) during the harvesting season than the non-harvesting period in both age groups. Kitchen wastes were next in abundance (26-29%) and were significantly more abundant in non-harvesting season in growers only and in hens than in growers (P < 0.001). The dry matter, crude protein, crude fiber, calcium, phosphorous and metabolizable energy levels of crop contents were 91.1-92.5%, 12.9-15.5%, 4.17-7.07%, 0.43-0.90%, 0.28-0.38% and 3404.3-3636.2 Kcal, respectively. Crude protein, calcium and phosphorus levels were below the requirements for egg production and growth. The scavenging feed resource base was critically deficient in these nutrients during the harvesting season. As these nutrients are vital for production, supplementary feeds rich in these nutrients would probably result in increased egg production and optimum growth.

Two novel duck antibacterial peptides, avian beta-defensins 9 and 10, with antimicrobial activity.

Two novel avian beta-defensins (AvBDs) isolated from duck liver were characterized and their homologies with other AvBDs were analyzed. They were shown to be duck AvBD9 and AvBD10. The mRNA expression of the two genes was analyzed in 17 different tissues from 1-28-dayold ducks. AvBD9 was differentially expressed in the tissues, with especially high levels of expression in liver, kidney, crop, and trachea, whereas AvBD10 was only expressed in the liver and kidney of ducks at all the ages investigated. We produced and purified GST-tagged recombinant AvBD9 and AvBD10 by expressing the two genes in Escherichia coli. Both recombinant proteins exhibited antimicrobial activity against several bacterial strains. The results revealed that both recombinant proteins retained their antimicrobial activities against Staphylococcus aureus under a range of different temperatures (-70 degrees C -100 degrees C) and pH values (pH 3-12).

Crop content in nutrient-restricted versus non-restricted organic laying hens with access to different forage vegetations.

1. The purpose of this study was to evaluate how feed intake of organic layers varies according to type of forage vegetation available when hens are fed a normal concentrate for organic layers or a nutrient-restricted diet with whole wheat and oyster shells, assuming that the nutrient-restricted diet would reflect the capacity of the hens to forage. 2. Two 23-d experiments were arranged with chicken runs in a 2 x 2 factorial design with two types of complementary feed (concentrate with 184 g/kg dry matter (DM) crude protein vs whole wheat with 120 g/kg DM crude protein) and two types of forage vegetation (grass/clover vs a mixture of forbs in experiment 1 and grass/clover vs chicory in experiment 2): each experiment was carried out in three replications. 3. Twice during each experiment two hens from each run were slaughtered - two in the evening and two the following morning. Subsequently, the birds' crops were removed. Crop content was separated into 8 fractions. 4. For most feed items crop content was found to be significantly higher in the evening than in the morning. 5. Complementary feed significantly influenced the content of several feed items in the crop. In both experiments wheat-fed hens had a significantly higher amount of soil in the crops and a significantly lower amount of weed seeds compared to the concentrate-fed hens. Plant material and grit stone were significantly more abundant in wheat-fed hens only in experiment 2 and numerically more abundant in experiment 1, whereas the amount of oyster shells was significantly higher in wheat-fed hens in experiment 1 and numerically higher in experiment 2. 6. Type of forage itself only significantly influenced the amount of soil in the crops in experiment 1 and amount of seeds in experiment 2, since more soil was found in hens foraging on the mixed forbs and more seeds were found in the hens foraging on the chicory plots, respectively.

Effects of Lactobacilli and lactose on Salmonella typhimurium colonisation and microbial fermentation in the crop of the young turkey.

1. Three experiments were performed to examine the effects of Lactobacilli and lactose on microbial fermentation and Salmonella enterica serovar Typhimurium colonisation in the crop of the young turkey. 2. The following carboxylic acids were detected in the crop ingesta: formic, acetic, butyric, lactic, valeric, caproic, oxalic, phenyl acetic, succinic and fumaric; propionic, isobutyric and isovaleric acids were not detectable. 3. At the beginning of the night, there were considerable quantities of ingesta in the crop of young turkeys. During the scotophase, there were progressive reductions in the contents and pH. Moreover, there were linear increases in the concentration of lactic, valeric and caproic acids (by approximately 7-fold over 8 h). Much smaller changes in crop pH were observed in the study where dietary treatments of Lactobacilli were not included. 4. Chronic addition of lactose or Lactobacilli to the diet exerted modest effects on the carboxylic acid concentration in the crop contents but did not consistently influence colonisation of the crop by Salmonella enterica serovar Typhimurium. 5. Young turkeys confine eating to the hours of illumination (photophase) with a peak in consumption prior to the subjective dusk.

Development of a lavage procedure to collect crop secretions from live chickens for studying crop immunity.

The crop (ingluvies), an organ for food storage in most avian species, is located at the base of the oesophagus. Previous work in our laboratory showed that, following infection with Salmonella enteritidis, significant anti-S. enteritidis antibody levels could be found in the crops of these birds. Samples in these previous studies were obtained by flushing the interiors of crops excised from killed birds, which is both labour and animal intensive. A method was sought that allowed multiple sampling of the same birds over time. We found that lavage fluid could be administered directly into the crop down the oesophagus using a narrow-diameter plastic tubing attached to a syringe, and the fluid could then be aspirated back into the syringe. Antibody-containing crop secretions could be collected with minimal discomfort to the test animals. In a study where birds were challenged with S. enteritidis, immunoglobulin A anti-S. enteritidis titres 3 weeks post-challenge were similar in crop samples obtained by live lavage versus the flushing of crops removed from killed birds. Such a sampling procedure may provide researchers with a simple method to follow mucosal immunity in chickens following infection or vaccination regimens.

An immunohistochemical study of the ontogeny of the neuroendocrine system in the chicken oesophagus.

The ontogenesis and distribution of serotonin-, chromogranin A-, chromogranin B-, galanin-, neurotensin-, bombesin- and neuropeptide Y-immunoreactive elements were studied in the chicken oesophagus during pre- and post-hatching life. Unlike positive nerve elements, that were present in pre- and post-hatching life, positive endocrine cells were observed only during embryonic life in the oesophageal epithelium. The first endocrine cells, immunoreactive for serotonin and chromogranins, appeared on day 12, in the cervical and thoracic portions of the oesophagus. At the same age, but only in its distal portion, a few bombesin- and neurotensin-immunoreactive cells also appeared. The number of the endocrine cells progressively increased, reaching a maximum on day 15. They then decreased, with a cranio-caudal progression, until they disappeared a few days after hatching. Almost all the serotonin-immunoreactive cells but only a subpopulation of bombesin- and neurotensin-immunoreactive cells colocalized chromogranins. About half of this subpopulation also colocalized serotonin. All these cells reacted positively with Grimelius argyrophile stain. The mucosa of the crop never contained positive endocrine cells. Positive nervous elements appeared first in the wall of the terminal oesophagus and only one or two days later in the proximal oesophagus including the crop. Nervous elements immunoreactive for galanin first appeared from days 6 to 7, for neurotensin from days 7 to 8, for neuropeptide Y from 13 to 15 and for bombesin from 15 to 18. At day 15 galanin-immunoreactive ganglionic cells and fibres occupied both the myenteric and submucous plexus and galanin-positive nerve fibres could be seen throughout the oesophageal wall from the adventitia to a thin subepithelial network. Neurotensin- and neuropeptide Y-immunopositive ganglionic cells and fibres, by contrast, invariably occupied the muscular and submucous layers. Scattered bombesin-immunoreactive ganglionic cells were observed only in the myenteric plexus. The number of positive nerve elements progressively increased until some weeks after birth. Density and intensity were always much higher for galanin and neurotensin than for neuropeptide Y and bombesin.

Retention and distribution of aflatoxin in tissues of chicks fed aflatoxin-contaminated poultry rations amended with soil.

The effects of silty clay loam on aflatoxin B1 (AFB1) retention and distribution were investigated when added to diets of chicks fed aflatoxin-contaminated rations. One hundred 14-d-old White Leghorn chicks were fed a control ration (clean corn), a low aflatoxin-contaminated ration (120 ng AFB1/g), a high aflatoxin-contaminated ration (700 ng AFB1/g), or a high aflatoxin-contaminated ration (700 ng AFB1/g) + 10% or 25% soil. Livers, crops and breast muscles in each group were pooled and analyzed for AFB1 and metabolites. The addition of soil significantly reduced the AFB1 levels in the livers, although the reduction was less when 10% soil was fed compared with the 25% soil feeding. AFB1 concentrations in the crops of chicks fed high aflatoxin-contaminated ration without soil was statistically indistinguishable from the chicks in the other groups. AFB1 concentrations were significantly reduced in the breast muscles of chicks fed 10% or 25% soil compared to chicks fed the high aflatoxin-contaminated ration without soil. Aflatoxin B2 was detected only in livers, crops and breast muscles from chicks fed aflatoxin-contaminated ration without soil. Aflatoxin M1 (AFM1) was detected only in livers and crops of chicks fed aflatoxin-contaminated ration without soil and only in breast muscles of chicks fed the low aflatoxin-contaminated ration and high aflatoxin-contaminated ration + 25% soil. AFM1 concentration was significantly higher in the crops of chicks fed high aflatoxin-contaminated ration without soil.