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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., Competing Interests: Declaration of Competing Interest The authors declare that we have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Domestic chickens ( Gallus gallus domesticus ) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.5 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. Based upon mean clinical severity scores, the no observed adverse effect level (NOAEL) was 3.42 mg/kg/day, and the lowest observed adverse effect level (LOAEL) was 10.25 mg/kg/day. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED 50 ) was 4.62 ± 0.98 mg/kg/day. The ED 50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED 50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, possible causes include the assays were insensitive, relevant immune functions were not examined, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity.

1. The purpose of the present study was to determine if intracerebroventricular (ICV) and intraperitoneal (IP) injection of polyinosinic-polycytidylic acid (poly I:C), a viral mimetic that binds to toll-like receptor-3 (TLR3), affects food intake, voluntary activity, cloacal temperature, plasma corticosterone (CORT) and glucose concentrations, and crop emptying rate in chicks (Gallus gallus). 2. Both ICV and IP injection of poly I:C significantly decreased food intake. 3. IP but not ICV injection of poly I:C significantly suppressed voluntary activity, whereas ICV injection decreased time spent sitting. Both ICV and IP injection of poly I:C significantly increased plasma CORT and glucose concentration. Neither ICV nor IP injection of poly I:C significantly affected cloacal temperature. 4. In addition, ICV injection of poly I:C significantly reduced crop emptying rate, whereas IP injection had no effect. 5. These results suggested that central TLR3 is related to anorexia, stress response and retardation of crop emptying while peripheral TLR3 is related to anorexia, change in behaviour and stress responses during viral infection in chicks.

Infectious conditions are associated with reduced food passage through the digestive tract in both mammals and chicks; however, the precise mechanism mediating this response in chicks remains unclear. The purpose of the present study was to determine if mast cells, a blood cell type which plays an important role in the immune system, might affect food passage through the digestive tract in chicks. Specifically, we performed intraperitoneal (IP) injections of compound 48/80, an inducer of mast cell degranulation, and measured crop emptying. The IP injection of compound 48/80 significantly reduced the crop-emptying rate, but it did not affect the proventriculus to small intestine transit rate or the number of defecations. We also found that IP-injected histamine, which is secreted by mast cells, also reduced the crop-emptying rate. In addition, IP injection of 2-pyridylethylamine (histamine H1 receptor agonist), but not dimaprit, (R)-(-)-α-methylhistamine, and VUF8430 (histamine H2, H3, and H4 receptor agonists, respectively), reduced the crop-emptying rate, implying that histamine reduces the crop emptying rate via the histamine H1 receptor. Finally, we found that IP injection of compound 48/80 reduced mRNA expression of histidine decarboxylase, a rate-limiting enzyme for histamine synthesis, in the esophagus and proventriculus at 1 h and the proventriculus and duodenum at 3 h after the injection. In sum, the present study suggests that the degranulation of mast cells causes a reduction in the crop-emptying rate, possibly via the histamine pathway in chicks., (Copyright © 2018 Elsevier Inc. All rights reserved.)

l-tryptophan (l-Trp), an essential amino acid, is well known as a precursor of 5-hydroxytryptamine (5-HT) and melatonin. In mammals, l-Trp itself has been reported to suppress gastric emptying in mammals. In addition, 5-HT and melatonin are found in the gastrointestinal tract and affect food passage from the digestive tract in mammals. While the function of these factors in mammals is documented, there is little knowledge on their function in the digestive tract of birds. Therefore, the purpose of the present study was to determine if l-Trp and its metabolites affect the crop emptying rate in chicks (Gallus gallus). We also investigated the effects of kynurenic acid (KYNA) and quinolinic acid (QA), which are metabolites of the kynurenine pathway for l-Trp. Oral administration of l-Trp significantly reduced the crop emptying rate in chicks. Among the metabolites, intraperitoneal injection of 5-HT and melatonin significantly reduced the crop emptying rate, whereas KYNA and QA had no effect. The present study suggests that l-Trp, 5-HT, and melatonin inhibit the movement of food in the digestive tract and thereby affect the utilization of nutrients in the diet of chicks., (Copyright © 2018 Elsevier Inc. All rights reserved.)

1. The aim of this study was to examine single-dose toxicokinetics of deltamethrin, a broad-spectrum pyrethroid insecticide, for treatment of broiler chickens. 2. Twenty male broiler chickens were used. Animals were divided into two groups, each comprising 10 animals. An intravenous dose of 0.75 mg of deltamethrin/kg body weight was given intravenously to the first group and the same dose (0.75 mg/kg body weight) was administered by intracrop by gavage to the second group. Blood samples were also collected at specified intervals. 3. Serum deltamethrin levels were measured via micro-electron capture detection with gas chromatography equipment. According to the serum deltamethrin level-time curve, deltamethrin tended to distribute according to a two-compartment open model. 4. The half-life at β phase (t 1/2 β ), mean residence time (MRT) and area under the concentration time curve in 0-∞ (AUC 0→∞ ) values after intravenous application of deltamethrin were 4.00 ± 0.76 h, 4.65 ± 0.75 h and 702.27 ± 236.07 ng h/ml, respectively. Furthermore, the absorption half-life (t 1/2a ), maximal concentration in serum after intracrop administration (C max ), time needed to reach C max (t max ), t 1/2 β , MRT and AUC 0→∞ values after intracrop application of deltamethrin were determined to be 0.18 ± 0.06 h, 19.65 ± 4.58 ng/ml, 0.70 ± 0.10 h, 7.27 ± 1.36 h, 10.46 ± 1.84 h and 153.33 ± 30.83 ng h/ml, respectively. The bioavailability of deltamethrin was 21.83%. 5. It was concluded that deltamethrin was rapidly but incompletely absorbed after intracrop administration and bioavailability was at a low level. The t 1/2 β and MRT of the deltamethrin were short for both intracrop and intravenous applications, and the risk of toxic and residual effects of deltamethrin is therefore limited.

The gastrointestinal microbial community in broiler chickens consists of many different species of bacteria, and the overall microbiota can vary from bird to bird. To control pathogenic bacteria in broilers and improve gut health, numerous potential dietary amendments have been used. In this study, we used a pyrosequencing platform to evaluate the effect of sodium bisulfate on microbiota of the crop, cecum, and ileum of broiler chickens grown over several weeks. The diversity information in each digestive organ sample exhibited considerable variation and was clearly separable, suggesting distinct bacterial populations. Although no apparent microbial clustering occurred between the control and the dietary treatments, we did observe shifts in overall microbiota populations in the crop, ileum, and ceca as well as changes in specific microorganisms such as Bacteroides, Clostridium, and Lactobacillus species that were identified as birds became older., (© 2015 Poultry Science Association Inc.)

Corticotrophin-releasing hormone (CRH) plays an important role in response to stress, and exerts a physiological effect via its receptor, CRH receptor type-1 (CRH-R1) and CRH receptor type-2 (CRH-R2) with high affinity to CRH-R1 in mammals. Urocortin-3 (UCN-3), a CRH family peptide, is an endogenous ligand for CRH-R2 in mammals. The physiological roles of UCN-3 and CRH-R2 have been investigated in mammals, although their roles still need to be clarified in chicks (Gallus gallus). Few studies have been performed comparing the physiological responses of CRH and UCN-3 in chicks. Therefore the present study was conducted to investigate the effect of intracerebroventricular (ICV) injection of UCN-3 on food intake, rectal temperature, crop-emptying rate and behaviors in chicks, and to compare these physiological responses with the effects resulting from CRH injection. The ICV injection of 20 and 80 pmol UCN-3 decreased food intake, increased rectal temperature and decreased crop-emptying rate and the results were similar to those achieved with CRH. The injection of both UCN-3 and CRH increased spontaneous activity but the behavioral patterns were different: CRH increased the number of vocalizations while UCN-3 increased the number of jumps, wing-flaps and scratching behaviors. These results suggest that UCN-3 regulates food intake, body temperature, and gastric emptying via the CRH-R2 in the brain of chicks, and these effects were similar to those induced by CRH., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Six free-flying California condors (Gymnogyps californianus) were diagnosed with acute lead toxicosis that caused crop distension and stasis. Between January 2006 and January 2007, the birds were referred to the Phoenix Zoo in Arizona for emergency treatment. In 5 birds, an ingluviotomy was performed to place a feeding tube from the crop to the proventriculus, which allowed a temporary bypass of the dysfunctional esophagus until normal function and motility were regained. A crop-support pressure bandage was placed in 4 birds to improve crop emptying into the proventriculus and to prevent crop distension. Although chelation therapy is the gold standard treatment for lead toxicosis, severe cases of lead-induced crop stasis are not acutely reversible with pharmaceuticals. In these condors, placement of a feeding tube was deemed prudent to ensure a viable enteric route of nutritional support during the standard treatment and recovery period in acute lead toxicosis with crop stasis.

Obestatin has recently been discovered in the rat stomach. As for ghrelin, the 23-amino acid obestatin is also derived from post-translational processing of the prepro-ghrelin gene but seems to have opposite effects on feed intake. In avian species, ghrelin is mainly present in the proventriculus and decreases feed intake, as opposed to its orexigenic properties in mammals. An obestatin-like sequence was also found in the avian ghrelin precursor protein but the potential involvement of this peptide in appetite regulation of chickens is unclear. We therefore investigated the effects of a single peripheral administration of this predicted "chicken" obestatin peptide on voluntary feed intake of 7- to 9-day-old meat-type and layer-type chicks. "Chicken" obestatin was injected intraperitoneally or intravenously at a dose of 1 nmol or 10 nmol/100 g body weight and feed intake was measured up to 4 h post injection. None of these treatments did reveal any effect of the putative "chicken" obestatin on appetite of either meat-type of layer-type chicks. Furthermore, "chicken" obestatin also failed to affect the in vitro contractility of muscle strips from crop and proventriculus. In conclusion, in the given experimental settings, the putative "chicken" obestatin has indistinctive physiological effects on feed intake and in vitro muscle contractility of gut segments, and hence its functional properties in ingestive behavior of avian species remain obscure., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Effects of Aspergillus niger-fermented Terminalia catappa seed meal-based diet on the activities of alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST) and gamma-glutamate transferase (gamma-GT) in the crop, small intestine, gizzard, heart, liver and serum of broiler chicks were investigated. Milled T. catappa seed was inoculated with spores of A.niger (2.21 x 10(4) spores per ml) for 3 weeks. Forty-five day-old broiler chicks weighing between 27.62 and 36.21 g, were divided into three groups. The first group was fed soybean-based (control) diet; the second on raw T. catappa seed meal-based diet; and the third on A. niger-fermented T. catappa seed meal-based diet for 7 weeks. The results revealed a significantly increased (p<0.05) activity of ALP in the tissues. Contrarily, there were significant reductions (p<0.05) in the activities of ALP, ALT, AST and gamma-GT in the liver and heart of the broilers fed the raw T. catappa seed meal-based diet while there were significant increase (p<0.05) in the activities of these enzymes in the serum of the broilers in this group. The data obtained showed that A. niger-fermented T. catappa seed meal reduced the toxic effects of the raw seed meal on the tissues of broiler chicks., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

A study was conducted to evaluate the effect of experimental chlorate product (ECP) feed supplementation on Salmonella Typhimurium (ST) in the crop and ceca of market-age broilers. In trial 1, 160 market-age broilers were randomly assigned to 8 treatment groups and replicated twice, with 20 broilers per pen for 1 wk. Trial 2 used the same design, but used 80 market-age broilers with 10 broilers per pen. Treatments were as follows: 1) control feed + double-distilled drinking water (dd H(2)O); 2) control + 18.5% experimental zeolite carrier with dd H(2)O; 3 to 7) control feed supplemented with 0.5, 1.0, 5.0, 10.0, or 18.5% of a feed grade ECP + dd H(2)O; 8) control feed + 1x ECP (0.16% w/v; containing 15 mM chlorate ion equivalent) added to dd H(2)O. Seven-week-old broilers were provided experimental treatments for 7 d, killed, and then ceca and crops were removed and evaluated for ST. Broilers fed 5 to 18.5% ECP or water ECP had a significantly lower (P < 0.05) incidence of ST in the crop (36 to 38% and 14%, respectively) when compared with the control (60%). Broilers fed 10% ECP or water ECP had significantly lower ST crop concentrations (1.03 log(10) and 0.38 log(10) ST/g, respectively) when compared with broilers fed a control diet (1.54 log(10) ST/g). Crop and ceca ST incidence (32 to 48%) and concentration (1.00 to 1.82 log(10) ST/g) were significantly lower in broilers fed 5 to 18.5% ECP as compared with the control (78%; 2.84 log(10) ST/g). Broilers fed 5% or greater ECP had significantly higher water consumption (380 to 580 mL water/d) and litter moisture (31 to 56%) when compared with the control (370 mL water/d; 23% moisture). Only broilers fed 18.5% ECP had significantly lower 7-wk BW (2.77 kg of BW) when compared with the controls (3.09 kg of BW). Average daily gains were significantly depressed in broilers fed 10 or 18.5% ECP compared with the controls. These results indicate broilers supplemented with feed

Two studies were conducted to evaluate the effects of melatonin on Salmonella Enteritidis infection in experimentally challenged laying hens subjected to a forced molt. Leghorn hens (>50 wk of age) were randomly assigned to rooms, acclimated to a 16L:8D regimen, and provided ad libitum access to a nonmedicated mash layer diet and water. Birds in one room were molted (8L:16D; complete feed withdrawal), whereas birds in the second room served as nonmolted controls (CONT). Within each room, birds were randomly assigned to melatonin treatment (MEL; 12 birds/treatment), dosed orally commencing the same day as feed withdrawal for 10 d: (experiment I: 0 or 5 mg of melatonin; experiment II: 0, 10, or 20 mg of melatonin). Three days following feed withdrawal, all birds were experimentally infected with Salmonella Enteritidis, and after 10 d of feed withdrawal, all birds were killed and necropsied. In experiment I, concentrations of Salmonella Enteritidis in the cecal contents and the number of Salmonella Enteritidis-positive tissues from the crop, ceca, liver, spleen, and ovary were higher (P < 0.0001) in the MOLT compared with the CONT treatments. No differences (P > 0.10) were observed in any of the parameters examined due to MEL treatment. For experiment II, cecal concentrations of Salmonella Enteritidis were generally higher in the MOLT compared with the CONT treatment and within molted birds, cecal concentrations were higher in the MEL treatment (P < 0.05). Melatonin treatment in molted birds increased (P < 0.05) the percentage of positive crops in the MOLT+20 MEL treatment (P < 0.05). Salmonella-positive cecal tissue was increased (P < 0.001) in MOLT compared with CONT birds and was also higher in MOLT+10 MEL and MOLT+20 MEL birds compared with the MOLT-only treatment. Results from the current research suggest that dosage with high levels of melatonin may exacerbate Salmonella Enteritidis infection in layers subjected to forced molt.

Formalin administered (15 and 20 mL) into the crops of White Leghorn cockerels resulted in behavioral alterations, included depression, dullness, staggering, somnolence, anorexia, and decreased frequency of crowing. A significant decrease was observed in red blood cell counts, hemoglobin concentration, packed cell volume, and leukocyte counts in birds fed higher levels of formalin. Decreasing and increasing trends in concentrations of serum proteins and enzymes, respectively, were observed with increases in formalin doses. Significantly lower blood glucose and testosterone levels and significantly (P < 0.05) higher blood urea and creatinine concentrations were observed in birds fed higher formalin levels. No gross or microscopic lesions were observed in the birds fed different levels of formalin mixed in feed. These changes suggested that the formalin mixed in feed might have evaporated, and, hence, the amount ingested might have been too low to induce pathological changes. It was concluded from the present study that formalin mixed up to 5 mL/kg of feed, corresponding to 10 mL/bird of 3% formalin in drinking water by crop tube had no adverse effects on the health of White Leghorn cockerels.

This study compared the adverse effects of formalin administered by two different methods. Formalin mixed with the feed (2.5, 5.0 and 10 ml/kg) was given to 10-week-old White Leghorn cockerels for a period of 8 weeks. Simultaneously in other groups, a 3% solution of formalin was administered into the crops (5, 10, 15 and 20 ml/bird/day). Total amount of formalin utilized during the experiment in the feed of individual bird of groups given 2.5, 5 and 10 ml/kg was 6.25, 3.9 and 1.6% higher than those administered 5, 10 and 20 ml of 3% formalin into crop, respectively. Body mass and feed intake in all feed-mixed groups and those given 5 and 10 ml formalin (3%) into the crop were not significantly different from control. Administration of 15 and 20 ml formalin (3%) into crop resulted in depression, delayed onset of crowing, significantly decreased feed intake, lower body mass, decreased mass and volume of testes, ulceration in crops, sloughing of mucosa and petechial haemorrhages in proventriculus. All the groups given formalin had significantly smaller diameters of seminiferous tubules. Kidneys of the birds administered formalin into crop exhibited pyknotic nuclei of epithelial cells in proximal tubules. Non-significant differences in different parameters and lesser degree of pathological changes in birds given formalin-mixed feed than their corresponding crop-administered groups suggested that formalin present in the feed had partially evaporated. Therefore, birds ingested less amount of formalin than that originally mixed in the feed.

We investigated the effect of central and peripheral glucagon-like peptide-1 (GLP-1) on crop emptying in growing chicks. Intracerebroventricular injection of two concentrations of GLP-1 (15 and 60 pmol) similarly suppressed crop emptying, compared with control chicks. The delay in crop emptying induced by GLP-1 (15 pmol) was partly attenuated by co-administration with exendin (5-39) (600 pmol), a GLP-1 receptor antagonist, although exendin (5-39) alone did not affect crop emptying. On the other hand, intraperitoneal administration of several doses of GLP-1 (120, 300 and 3000 pmol) did not alter crop emptying. The present study revealed that central, but not peripheral, GLP-1 inhibits crop emptying in chicks.

1. This study was conducted to evaluate the protective effect of natural sodium bentonite (NaB) in the prevention of toxic effects of aflatoxins. Five hundred and twenty-eight 1-d-old Ross male broiler chickens were housed in pens (22 chickens per pen) for 42 d. There were 3 inclusion rates of NaB (0, 2.5, and 5 g/kg) and 2 of aflatoxins (0 and 3 mg/kg food). Each treatment had 4 replicates of 22 chickens. 2. All chickens treated with aflatoxin and without bentonite were adversely affected. NaB treatment at 5.0 g/kg improved body weights at 42 d of age by 31.3%, increased food intake by 23.8% and improved productive efficiency by 40.1%. Weights of liver, heart, pancreas and crop and biochemical variables were not affected by dietary NaB. However, serum phosphorous concentration was reduced by 30% compared with chickens that received aflatoxin. 3. NaB caused no adverse effects on chickens that did not receive aflatoxin. 4. It is concluded that NaB at pH 7.9 partially neutralises the effects of aflatoxins on broiler chickens when included at 5.0 g/kg in the diet.

1. The effect of ketone bodies on crop emptying was studied in chickens in 2 experiments. In the first, the effect of beta-hydroxybutyrate, acetoacetate or acetone on relative crop content was measured. The effects of dietary medium and long chain triacylglycerols upon serum beta-hydroxybutyrate were investigated in the second. 2. beta-Hydroxybutyrate, but not acetoacetate and acetone, delayed crop emptying in a dose dependent fashion. Serum beta-hydroxybutyrate concentration was high in chicks given medium chain triacylglycerol, when compared with long chain triacylglycerol. 3. The results suggest that delayed crop emptying induced by medium chain triacylglycerol could partly be explained by an enhanced concentration of serum beta-hydroxybutyrate, which is the result of the rapid oxidation of medium chain fatty acids.

1. The effects of partially hydrolysed guar gum (PHGG) or intact guar gum (GG) on feeding behaviour and crop emptying rate in growing chicks were investigated. 2. Several combinations of dietary PHGG and GG at 50 g per kg diets were prepared for a feed intake experiment. Birds (1 7-d-old) were given diets for 3 h after 16 h fasting, and food consumption was measured at 1 h intervals. The food intake rapidly decreased as the dietary GG content increased even at 1 h after feeding. 3. The rate of food passage from the crop was also investigated with birds (20-d-old after 16 h fasting. Birds were tube-fed diets having several ratios of dietary PHGG and GG. After 1 h of feeding, the diet remaining in the crop was measured after drying. The crop emptying rate decreased linearly as dietary PHGG concentration decreased. 4. The present study suggests that partial hydrolysis of dietary GG improve both feeding behaviour and food passage from the crop in growing chicks.

In a first trial glycerol was tested as a feed ingredient for broiler chickens. The influence of glycerol supplementation on weight gain, feed intake, feed conversion ratio and N-balance was proved. 90 Broiler chickens (Lohmann Meat) were fed ad libitum in 6 groups with nearly isoenergetic diets based on corn and soybean meal with 23% crude protein and 0; 5; 10; 15; 20 or 25% pure glycerol in the DM. During a feeding period of 31 days animals had have a very good intake of all experimental diets. The highest weight gains were observed in the groups with 5 and 10% glycerol (34.9 and 35.3 g/animal.d, resp.). However, this effect was not significant compared to the control group (34.3 g/animal.d), but was significant superior to the gain of groups with 20 and 25% glycerol in the diet (30.2 and 26.6 g/animal.d, resp.). The feed conversion ratio was unchanged up to 10% glycerol (1.65 kg/kg gain) and rose to 2.08 kg/kg gain with 25% glycerol. Up to 20% glycerol the N-balance (1.6 to 1.8 g N/animal.d) was positively correlated with the glycerol content in the diet (r = 0.98). The estimation of the plasma glycerol level 2 hours after feeding indicated a remarkable increase already with a 5% supplementation of glycerol from 0.65 (control) to 4.36 mmol/l. Further supplementation caused on average 11 to 54 mmol glycerol/l varying considerably between the individual animals. In general 25% glycerol in the diet caused the lowest performance and pathological changes in the crop epithelium, liver and kidneys. From the point of view of weight gain, feed intake, and feed conversion ratio as well as N-balance a supplementation of 5 to 10% glycerol seems to be beneficial.

Synthetic dog neuromedin U-25(d-NMU-25), U-8(d-NMU-8) and their fragments wer examined for contractile activity on chicken crop smooth muscle preparation. The relative activities of d-NMU-25, d-NMU-25(15--25)NH2 and d-NMU-8 to porcine neuromedin U-8 (p-NMU-8) were 1.69, 2.54 and 5.78, respectively. High activity of d-NMU-8 may be attributable to the N-terminal pGlu residue, which provides resistance to aminopeptidases. Various NMU-8 analogs, having various amino acids, N alpha-acetylated amino acids, D-amino acids, or simple organic acids at position 1, were synthesized and evaluated for contractile activity. None of the substitutions caused a significant decrease of the biological activity. Modification at the N-terminal to give aminopeptidase resistance produced analogs with increased contractile activity, presumably because they were not degraded by soluble enzymes released into the bioassay fluid from isolated chicken crop tissue.

To develop a highly potent agonist and to examine the structure-contractile activity relationship of neuromedin U-8(NMU-8), seventeen analogs were synthesized and tested for contractile activity on isolated chicken crop smooth muscle preparations. The analogs were designed to examine the contributions of cyclic structure and acidic function at the N-terminal of NMU-8 and NMU-8(2--8) to the biological activity. The relative activity (RA) values of NMU-8 analogs were as follows: [Dp-Glu1]-NMU-8,5.50; [pyrohomoglutamyl(pHgu)1]-NMU-8,4.65;[D-pHgu1]-NMU-8, 4.66; [Asp1]-NMU-8, 11.4; [acetyl(Ac)-Asp1]-NMU-8, 9.81; [Ac-Glu1]- NMU-8, 18.6; [succinyl (Suc)-Tyr1-NMU-8,69.3; [3-sulfoalanyl (Sal)1]-NMU-8, 12.7. The RA values of NMU-8(2--8) analogs were as follows: alpha-picolinyl (Pic)-NMU-8 (2--8), 7.96; 2-furoyl (Fur)-NMU-8, (2--8), 9.91; 2-thiophenecarboxyl (Thi)-NMU-8 (2--8), 3.41; 4-hydroxyphenylpropionyl (Hpp)-NMU-8(2--8), 3.20; o-phthalyl (Pht)-NMU-8 (2--8), 11.3; Suc-NMU-8 (2--8), 109; malonyl (Mlo)-NMU-8 (2--8), 17.9; maleyl (Mle)-NMU-8 (2--8), 31.6; glutaryl (Glt)-NMU-8 (2--8), 81.3; The potencies of the analogs were higher than that of p-NMU-8. Suc-NMU-8 (2--8) showed the highest potency among the analogs synthesized. The results reveal that the carboxylic acid group at the N-terminus of NMU-8 makes a major contribution to the activity.

Pituitary glands of rats, injected with estrogen to increase the prolactin (PRL) storage in secretory granules, were submitted to various extraction procedures for prolactin. Homogenization and centrifugation of pituitary tissue, in Tris-HCl buffer, pH 7.3, yielded a small amount of radioimmunoassayable prolactin, which increased remarkably after extraction in alkaline pH, disruption of granular membranes with Lubrol and specially after treatment with 2.5 mol/l urea. Nb2 lymphoma cell and pigeon crop sac bioassay (BA) revealed higher levels of bioactivity after extraction in Tris buffer, pH 7.3, in comparison to RIA, with BA/RIA ratios of 1.4 and 2.3, respectively. Bioassays of pituitary PRL extracted with Lubrol and alkaline medium, were less effective in quantifying PRL than RIA. Treatment of pituitary homogenates with urea produced the highest levels of PRL by both BA and RIA, with BA/RIA ratios close to 1. The thorough depolymerization of big PRL effected by urea produced the release of monomeric subunits which allows a complete quantification of the total content in the pituitary gland.

Whether medium-chain triacylglycerols (MCT) affect the plasma concentration of cholecystokinin (CCK) and crop-emptying rate in chicks was investigated after 0, 30, 60, 90, 120 or 180 min of diet intubation. Triacylglycerol sources used were corn oil [containing long-chain triacylglycerols (LCT)], glyceryl tricaprate and glyceryl tricaprylate at a level of 200 g/kg diet. Plasma CCK concentration was significantly enhanced in chicks given the two MCT treatments, but not in those given the LCT treatment, after 30 min feeding relative to the initial level. At all time points, chicks fed the diet containing LCT had significantly lower plasma CCK concentrations than those fed MCT, and chicks fed glyceryl tricaprate had higher concentrations than those fed glyceryl tricaprylate. Dietary MCT sources significantly delayed diet passage from the crop compared with dietary LCT. These results indicate that MCT are more potent stimulators of CCK secretion in chicks than LCT.

Contractile activity of porcine neuromedin U-25 (p-NMU-25) and various neuromedin U (NMU) peptide fragment amides was examined on chicken crop smooth muscle preparation. The relative activity (expressed as RA value) of p-NMU-25 to porcine neuromedin U-8 (p-NMU-8) was 5.51 +/- 0.09, and p-NMU-25 (15-25) was the most potent fragment with an RA value of 7.78 +/- 0.05. All C-terminal 11-peptide amides of rat, rabbit, and frog NMU peptides retained activity about three-fold higher than the corresponding C-terminal 8-peptide amides. The peptide segment Asn15-Arg-Arg17 of p-NMU-25, as well as the corresponding positions of various NMU peptides: Ser13-Gly-Gly15 of rat NMU and Ser15-Arg-Gly17 of rabbit and frog NMUs, appeared to be involved in the structural requirements for increased contractile activity in the assay system.

The pigeon crop-sac is a well-known target organ of prolactin (PRL). Pukac and Horseman (Endocrinology 114: 1718, 1984) reported that injections of the hormone caused changes in the expression of several specific proteins in that organ. We investigated the possibility that measuring the amounts of three of these proteins might improve the precision of the local pigeon crop-sac assay for PRL. Pigeons were given four injections of phosphate-buffered saline or different doses of ovine (o) PRL for 2 days and were killed on day 3. The DNA and total protein content of their crop-sac mucosal epithelial cells were measured and a supernatant of homogenized epithelial cells was processed by SDS-PAGE. The amounts of the three specific proteins in the stained gels were measured by densitometry. Treatment with oPRL increased the concentration of two of these proteins in the crop mucosal tissue (CP 14 and CP 25) and decreased that of the third one (CP 17). Measurement of total protein or of changes in the individual protein bands gave dose-response relationships with poor indices of precision (lambda greater than 0.3). Measurement of DNA content gave an assay endpoint with a reasonably good lambda value (0.16) but when the changes in the amounts of CP 14 and CP 25 were expressed as ratios to the changes occurring in CP 17, very precise assay endpoints (lambda = 0.06-0.08) were obtained.

Scirpentriol (STO) (3 alpha,4 beta,15-trihydroxy-12,13-epoxytrichothec-9- ene), the parent alcohol of the family of acetylated scirpenol mycotoxins produced by several Fusarium species, has been implicated in mixed toxicoses of animals, but there is not a general description of its toxicity in chickens. Dietary STO (0, 2, 4, 8, 16, and 32 micrograms/g feed) was fed to four groups of 10 male day-old broiler chickens for 3 wk. The minimum effective dose (MED) for reducing growth rate significantly (P less than .05) was 4 micrograms/g. The same MED was found for increased serum alkaline phosphatase and relative weight of the gizzard. Unlike literature reports for two other trichothecene mycotoxins, T-2 toxin and diacetoxyscirpenol (DAS), STO impaired feed conversion efficiency but did not alter spleen or pancreas size. The MED of STO for decreases in serum lactic dehydrogenase and aspartate aminotransferase was 8 micrograms/g, but the MED for decreased serum albumin and total proteins and regression of the bursa of Fabricius was 16 micrograms/g. Serum sodium, potassium, and calcium were not altered at the highest dose, 32 micrograms/g, but serum phosphate, uric acid, and cholesterol were decreased by 32 micrograms/g. Serum chloride was increased slightly but significantly (P less than .05) at 16 and 32 micrograms/g. Based on these results, STO toxicosis of chickens can be differentiated from those of T-2 toxin and DAS and its toxicity appears sufficient to warrant further attention.

1. Whether the ingestion of excess phenylalanine (Phe) or tyrosine (Tyr) in diets alters the release of cholecystokinin (CCK) into the blood was investigated in chickens. A single meal of control, Phe excess, or Tyr excess diets was given through a stomach tube, followed by the CCK determination with specific CCK-8 antibody. 2. Plasma CCK level increased significantly at 30 min after feeding the diets: about 2.5 times the basal level in the control group and about 3 times the basal level in both of the experimental groups. 3. The Phe excess diet significantly delayed crop emptying rates compared to the control diet, while the Tyr diet on the contrary enhanced the emptying rate. 4. Enhanced plasma CCK levels and delayed crop emptying by Phe excess diet are suggested to be associated with depressed food intake.

The ultrastructural effects of drugs enhancing, by different mechanisms, cholinergic transmission in the crop-sac (the target for prolactin secretion in birds) and the anterior pituitary lactotrophs, were studied in pigeons (Columba livia). The systemic or intraventricular administration of physostigmine, carbachol and muscarine produced maximal crop-sac stimulation with milk-like secretion, as demonstrated by the observation of ultrastructural changes in the lactiferous areas through scanning and transmission electron microscopy of the crop-sac mucosa. A marked activation was also observed in anterior pituitary lactotrophs. Crop-sac and anterior pituitary lactotrophs stimulatory effects were prevented by an atropine pretreatment, but not by mecamylamine and pempidine pretreatments. The present results suggest that muscarinic receptors at the hypothalamic and/or anterior pituitary level are involved in avian species in the control of prolactin secretion.

The effects of relaxin (RLX), a hormone that has previously been demonstrated to have mammotrophic properties, were studied in the pigeon crop sac, a well-known target organ for mammotrophic and lactogenic hormones, and compared with the effects produced by prolactin (PRL). The two hormones were injected directly over the crop at different doses and the response was evaluated after differing times of exposure. RLX causes a dose-related increase in wet and dry weights and [3H]thymidine and [3H]uridine uptake by the crop mucosa, as well as morphological changes indicating growth and differentiation of the epithelial cells similar to those occurring during physiological activation in incubation and hatching. At the doses assayed, the effects of RLX were nearly identical to those obtained following PRL in the short-term experiments, but differences in functional responses were found in the long-term experiment.

The pigeon crop-sac is an underappreciated and underutilized model that can be used to study the direct and indirect effects of hormones, growth factors, and other agents on cell proliferation and differentiative processes in vivo. It can thus allow the uncertainties that attend many in vitro methods to be avoided. In addition, the crop mucosal cells are homogeneous and the organ is structurally much less complex than most other hormone-responsive target organs, such as the mammary gland or prostate. The organ is well suited for various other studies such as analysis of second-messenger systems for PRL and growth factors and the effects of growth-inhibitory substances.

A pigeon crop-sac bioassay for prolactin was developed applying a morphometric approach for quantification of the epithelial cell proliferation induced by the hormone. A small male dove, indigenous from South America (Zenaida auriculata) previously castrated was used as experimental animal. The total dose of prolactin was divided into 4 daily injections administered systemically into the pectoral muscles. The number of the proliferated cell layers used as the bioassay end point was analyzed statistically. This procedure yields a highly sensitive bioassay with an excellent precision index, particularly well suited for quantification of the different molecular forms of pituitary PRL.

Dosages of 95% ethanol (0, .5, or 1 ml) with variable quantities of water were administered to mixed sex chicks (263 g initial weight) on each of 7 consecutive days. The 1 ml dosage of ethanol significantly reduced body weight gains and feed consumption and increased liver weight per 100 g of body weight. Gross crop lesions (accumulation of exudates and hemorrhage) were observed for both the .5 and 1 ml dosage level of ethanol. For birds given the .5 ml ethanol dosage, dilution with water tended to reduce the severity of crop lesions but not for birds given 1 ml ethanol. All levels of ethanol produced mild ataxia within 5 to 10 min of dosage. Mild or moderate hepatocellular fatty change was present in livers from 5 to 6 birds given 1 ml ethanol. Crop exudates were composed of necrotic cells, fibrin and bacteria. Crop walls of birds given 1 ml of undiluted ethanol were ulcerated and inflamed. Areas within the crop wall were hemorrhagic, edematous, and infiltrated by heterophils and mononuclear cells.

Present experiments were aimed at studying in pigeons the effects of some neuroleptic agents given systemically or into the 3rd cerebral ventricle on PRL secretion and following morphological changes of the crop-sac mucosa both by classical histological methods and scanning electron microscopy. In addition, such changes were also evaluated on the basis of a semiquantitative method using a 1-4 rating scale. 3- or 5-day systemic treatment with reserpine, haloperidol and (ł/-)-sulpiride produced an intense crop-sac response consisting of a marked epithelial hyperplasia and presence of milk-like material. Similarly, a much lower dose of haloperidol, clozapine, and the two enantiomers of sulpiride given into the 3rd cerebral ventricle for 3 consecutive days produced a marked crop-sac response. The l-sulpiride was more active in comparison to the d-enantiomer. In conclusion, present experiments show that, similarly to mammals, in pigeons neuroleptic drugs are able to stimulate prolactin secretion and suggest that these effects are mediated through an action at the hypothalamic and/or pituitary level by removing a tonic dopaminergic inhibition.

Lead-induced crop dysfunction is probably due to a direct action on the smooth muscle or the neural elements in crop tissue. Strips of crop tissue relax when exposed to lead chloride in vitro. We found that tetrodotoxin and the neurotransmitter antagonists propranolol, sotalol and apamin failed to alter lead-induced relaxation, suggesting that the effect is not neurally mediated. Lead, manganese, cadmium and theophylline inhibited calcium-induced contractions in depolarized crop tissue. However, lead, like the phosphodiesterase inhibitor theophylline and unlike the calcium-influx blocker verapamil, did not inhibit bethanechol- or potassium-stimulated contractions and calcium influx into crop tissue. This suggests that lead does not act by blockade of calcium influx. Lead stimulated cyclic AMP production in cell-free crop membrane preparations. Lead also enhanced manganese stimulation of cyclic AMP production. The results suggest that lead-induced relaxation may be due to stimulation of adenylate cyclase activity resulting in increased intracellular cyclic AMP levels.

The effects of dermorphin, a new potent opioid peptide, on structural and ultrastructural changes in the crop sac and in pituitary lactotrophs were assessed in pigeons (Columba livia). A single administration of dermorphin into the third cerebral ventricle (1 microgram) and the same dose repeated for 3 consecutive days both produced maximal crop sac stimulation, as documented by the presence of milk-like material as well as by scanning and transmission electron microscopy of crop sac mucosa. In addition, marked stimulatory effects were also observed in pituitary lactotrophs, as shown by stimulation of Golgi apparatus, enlargement of rough endoplasmic reticulum, increase in mitochondria size, and the presence of lysosomes and electron-opaque granules. The stimulatory effects of dermorphin on the crop sac and lactotrophs were completely prevented by naloxone, an antagonist at opiate receptors. Since dermorphin is a natural constituent of the avian brain, it has been suggested that this peptide may represent the still-obscure hypothalamic prolactin stimulatory factor.

The capacity of the pigeon pituitary gland to release prolactin was investigated in vivo, to evaluate its hypothalamic regulation and to establish the dominant hypothalamic factor for prolactin secretion. After 3 days of systemic administration of some physiological and pharmacological agents, followed by 2 consecutive days of local intradermal injections of prolactin into their crop sacs, the crop mucosa was scraped, dried and weighed. The substances tested were: oestradiol and tamoxifen (antioestrogen), thyrotophin-releasing hormone (TRH) and anti-TRH serum, perphenazine (releases prolactin in mammals) and bromocriptine (suppresses prolactin in mammals). Prolactin and anti-prolactin serum were tested as controls. While prolactin markedly proliferated and anti-prolactin serum significantly inhibited the mucosal weight, oestradiol, TRH and perphenazine dramatically depressed proliferation of the mucosa, suggesting that prolactin secretion was inhibited. Tamoxifen, anti-TRH serum and bromocriptine significantly increased the proliferation of the crop mucosa, indicating an increase in the endogenous release of prolactin. Since the effect of these substances on prolactin release in the pigeon is the opposite from their well-established effects in mammals, these results suggest, in a specific and homologous model, that the dominating regulator for prolactin in the pigeon is contrary to that in the mammal, namely prolactin-releasing factor, and that TRH may play a significant role in the physiological regulation of prolactin secretion.

The circadian time of PRL administration is an important determinant of its stimulatory activity in pigeon crop tissue. Based on previously published experiments we chose two phases of the entrained circadian cycle (0 and 9 h after light onset) which represent minimum and maximum crop sensitivity and examined several specific biochemical markers of mitogenesis and differentiation. These included DNA synthesis, ornithine decarboxylase activity, total RNA concentration, polyadenylated RNA concentration, and a specific PRL-induced messenger RNA. In confirmation of previous studies, crop weight was increased twice as much by ovine PRL (0.5 micrograms/g BW X 3 days) injected 9 h after light onset compared with the 0 h time of injection. A single local injection of 10 micrograms of ovine-PRL increased DNA synthesis by 4-fold when injection was made at 9 h but had no effect when injection was made at 0 h after light onset. In contrast, PRL stimulation of gene expression, including total RNA, polyadenylated RNA, and a specific PRL-induced messenger RNA, were quantitatively identical at each phase of the circadian cycle. Corollary with its central role in cell proliferation, ornithine decarboxylase activity was induced by PRL injected at 9 h after light onset. The mitogenic and differentiational PRL effects in crop are therefore partially dissociable and may depend on distinct mechanisms.

The putative chicken prolactin (chPRL) cDNA clone PRL101 was manipulated in vitro and cloned into the Escherichia coli expression vector pKK2332 to produce a plasmid coding for recombinant-derived mature chPRL (R-chPRL). Expression of this manipulated cDNA sequence in E. coli resulted in the production of a 23 kDa protein which cross-reacted with specific chPRL antisera in Western blots. The partially purified protein stimulated ring dove crop sac mucosa to proliferate in a PRL bioassay, demonstrating that the R-chPRL was biologically active. R-chPRL was expressed at a level of approximately 1.5% of total cell protein.

The effect of bombesin and of substance P was investigated in smooth muscle strips of the chicken crop. Bombesin in picomolar concentration (0.1 x 10(-12) - 5 X 10(-12) mol/l) caused a concentration-related contraction of the muscle strips. Substance P in nanomolar concentration (0.1 x 10(-9) - 10 x 10(-9) mol/l) was effective in the same manner. Tetrodotoxin (2 x 10(-7) mol/l) did not influence the contraction responses to either bombesin or substance P. The excitatory effect of bombesin and of substance P did not follow activation of cholinergic receptors since their effect on the crop smooth muscle was not antagonized by atropine (10(-4) mol/l) or by hexamethonium (10(-4) mol/l). Strips stored for 24 hours in the Tyrode's solution at 4 degrees C without a supply of oxygen maintained their full sensitivity to bombesin and to substance P. These results are consistent with a direct action of bombesin and substance P on the crop smooth muscle.