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.

Evaluation of neurobehavioral abnormalities and immunotoxicity in response to oral imidacloprid exposure in domestic chickens (Gallus gallus domesticus).

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 (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 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.

Physiological responses to central and peripheral injection of polyinosinic-polycytidylic acid in chicks.

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.

Compound 48/80 reduces the crop-emptying rate, likely through a histamine-associated pathway 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.

Effect of l-tryptophan and its metabolites on food passage from the crop in chicks.

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.

Toxicokinetics of the broad-spectrum pyrethroid insecticide deltamethrin in broiler chickens.

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 ß phase (t1/2ß), mean residence time (MRT) and area under the concentration time curve in 0-∞ (AUC0→∞) 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 (t1/2a), maximal concentration in serum after intracrop administration (Cmax), time needed to reach Cmax (tmax), t1/2ß, MRT and AUC0→∞ 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 t1/2ß 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.

Evaluation of feed grade sodium bisulfate impact on gastrointestinal tract microbiota ecology in broilers via a pyrosequencing platform.

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.

Comparison of brain urocortin-3 and corticotrophin-releasing factor for physiological responses in chicks.

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.

Ingluviotomy tube placement for lead-induced crop stasis in the California condor (Gymnogyps californianus).

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.

Peripheral "chicken" obestatin administration does not affect feed intake and gut muscle contractility of meat-type and layer-type chicks (Gallus gallus domesticus).

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.

Effects of Aspergillus niger-fermented Terminalia catappa seed meal-based diet on selected enzymes of some tissues of broiler chicks.

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.

Evaluation of an experimental chlorate product as a preslaughter feed supplement to reduce salmonella in meat-producing birds.

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

Influence of exogenous melatonin administration on Salmonella enteritidis colonization in molted layers.

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.

Effects of formalin feeding or administering into the crops of white leghorn cockerels on hematological and biochemical parameters.

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.

Pathological effects of formalin (37% formaldehyde) mixed in feed or administered into the crops 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.

Central, but not peripheral, glucagon-like peptide-1 inhibits crop emptying in chicks.

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.

Effect of sodium bentonite on the performance and blood variables of broiler chickens intoxicated with aflatoxins.

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.

Effect of ketone bodies on crop emptying in the chicken.

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.

Effects of partially hydrolysed guar gum on feeding behaviour and crop emptying rate in chicks.

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.