Broiler Cockerels Research Articles

XENOFOOD-An Autoclaved Feed Supplement Containing Autoclavable Antimicrobial Peptides-Exerts Anticoccidial GI Activity, and Causes Bursa Enlargement, but Has No Detectable Harmful Effects in Broiler Cockerels despite In Vitro Detectable Cytotoxicity on LHM Cells.

Entomopathogenic bacteria are obligate symbionts of entomopathogenic nematode (EPN) species. These bacteria biosynthesize and release non-ribosomal-templated hybrid peptides (NR-AMPs), with strong, and large-spectral antimicrobial potential, capable of inactivating pathogens belonging to different prokaryote, and eukaryote taxa. The cell-free conditioned culture media (CFCM) of Xenorhabdus budapestensis and X. szentirmaii efficiently inactivate poultry pathogens like Clostridium, Histomonas, and Eimeria. To learn whether a bio-preparation containing antimicrobial peptides of Xenorhabdus origin with accompanying (in vitro detectable) cytotoxic effects could be considered a safely applicable preventive feed supplement, we conducted a 42-day feeding experiment on freshly hatched broiler cockerels. XENOFOOD (containing autoclaved X. budapestensis, and X. szentirmaii cultures developed on chicken food) were consumed by the birds. The XENOFOOD exerted detectable gastrointestinal (GI) activity (reducing the numbers of the colony-forming Clostridium perfringens units in the lower jejunum. No animal was lost in the experiment. Neither the body weight, growth rate, feed-conversion ratio, nor organ-weight data differed between the control (C) and treated (T) groups, indicating that the XENOFOOD diet did not result in any detectable adverse effects. We suppose that the parameters indicating a moderate enlargement of bursas of Fabricius (average weight, size, and individual bursa/spleen weight-ratios) in the XENOFOOD-fed group must be an indirect indication that the bursa-controlled humoral immune system neutralized the cytotoxic ingredients of the XENOFOOD in the blood, not allowing to reach their critical cytotoxic concentration in the sensitive tissues.

Short Communication: Investigating woody breast disease and broiler chicken activity using an automated tracking software program

ABSTRACT Objective This research quantified the effect of woody breast disease (WBD) presence and severity on activity in broilers. Materials and Methods Broiler cockerel chicks (n = 27) were enrolled over 2 periods and individually housed. Video data were collected continuously from 21 to 55 d of age. Behavior was analyzed over a 4-h interval using EthoVision XT automated tracking software to quantify total activity. Birds were slaughtered at 55 d of age and assigned a woody breast severity score (0–2) based on manual palpation and visual observation. Results and Discussion Of the 25 birds that survived for the duration of the study, 6 birds were assigned a severity score of 0 (no evidence of WBD), 14 a severity score of 1 (firm focal lesions), and 5 a severity score of 2 (diffuse firmness of the entire pectoralis major muscle). Neither WBD presence nor severity had an effect on total activity (P > 0.05). In the present study, no effect of WBD on activity was detected using an automated tracking software program for behavior quantification. However, limitations of the software and the potential presence of microscopic lesions in birds with a severity score of 0 may be contributing to this outcome. Implications and Applications Although WBD has significant financial implications for the poultry industry, limited research has evaluated the effect of WBD on bird welfare and behavior. Future studies should measure a more diverse set of behaviors while also analyzing muscle histology to better elucidate any associations between WBD and behavior.

Validation of alternative behavioral observation methods in young broiler chickens

Continuous sampling provides the most complete data set for behavioral research; however, it often requires a prohibitive investment of time and labor. The objectives of this study were to validate behavioral observation methods of young broiler chickens using 1) 7 scan sampling intervals (0.5, 1, 3, 5, 10, 15, and 30 min) and 2) an automated tracking software program (EthoVision XT 14) compared to continuous behavioral observation, considered the gold standard for behavior observation. Ten 19-day-old Ross 708 broiler cockerels were included in this study. All behavior was video recorded over an 8-h period, and data were collected using a continuous sampling methodology. The same video files were utilized for analysis for scan sampling and automated tracking software analysis. For both analyses, the following criteria were used to identify which method accurately reflected the true duration and frequency for each behavior, as determined by continuous observation: R2 ≥ 0.9, slope was not different from 1 (P > 0.05), and intercept was not different from 0 (P > 0.05). Active, eating, drinking, and maintenance behaviors were accurately estimated with 0.5-min scan sample intervals. Active, inactive, eating, and maintenance behaviors were accurately estimated with 1-min scan sample intervals. Inactive behavior was accurately estimated with 5-min scan sample intervals. The remainder of sampling intervals examined did not provide accurate estimates, and no scan sampling interval accurately estimated the number of behavior bouts. The automated tracking software was able to accurately detect true duration of inactive behavior but was unable to accurately detect activity. The results of this study suggest that high-frequency behaviors can be accurately observed with instantaneous scan sampling up to 1-min intervals. Automated tracking software can accurately identify inactivity in young broiler chickens, but further behavior identification will require refinement.

Hypophagic effects of insulin are mediated via NPY1/NPY2 receptors in broiler cockerels.

Neuropeptide Y (NPY) plays a mediatory role in cerebral insulin function by maintaining energy balance. The current study was designed to determine the role of insulin in food intake and its interaction with NPY receptors in 8 experiments using broiler cockerels (4 treatment groups per experiment, except for experiment 8). Chicks received control solution or 2.5, 5, or 10 ng of insulin in experiment 1 and control solution or 1.25, 2.5, or 5 μg of receptor antagonists B5063, SF22, or SML0891 in experiments 2, 3, and 4 through intracerebroventricular (ICV) injection, respectively. In experiments 5, 6, and 7, chicks received ICV injection of B5063, SF22, SML0891, or co-injection of an antagonist + insulin, control solution, and insulin. In experiment 8, blood glucose was measured. Insulin, B5063, and SML0891 decreased food intake, while SF22 led to an increase in food intake. The hypophagic effect of insulin was also reinforced by injection of B560, but ICV injection of SF22 destroyed this hypophagic effect of insulin and increased food intake (p < 0.05). However, SML0891 had no effect on decreased food intake induced by insulin (p > 0.05). At 30 min postinjection, blood sugar in the control group was higher than that in the insulin group (p < 0.05). Therefore, the NPY1 and NPY2 receptors mediate the hypophagic effect of insulin in broiler cockerels.

Intestinal morphograhy of broilers fed diets supplemented with perlite

Aim of the study was to investigate effects of different levels of perlite on intestinal morphometry in broilers (Ross 308). A hundred and eighty broiler cockerels were randomly allocated into three experimental groups (3 replications and 20 broilers per pen) and fed experimental diets supplemented with different levels of perlite (0%, 2%, 4%). At 21, 28, 35 and 42 days of the study, 2 broilers were randomly selected from each replication, slaughtered and various sections of small intestine (1, 10, 30, 50, 70 and 90% of small intestine length) sampled for morphometry characteristics. Villi height, crypts depth and villus height / crypt depth ratio were measured microscopically. According to the results, a significant difference was observed on small intestine morphology post-perlite supplementation in experimental groups compared to control group. Supplementation of diet with perlite (2%) significantly increased average villi height in various sections of small intestine (1, 70 and 90%) in experimental birds on days 28 and 35 (P &lt; 0.05). In addition, similar findings were observed after addition of perlite (4%) on villi height on day 42 (P &lt;0.05). Furthermore, on day 28, average villi height and depth of liberkuhn crypts in small intestine (10%) differed significantly in cockerels fed diets containing 2% perlite in comparison to controls (P &lt; 0.05). These results suggest that supplementation of perlite in broilers’ diet can improve intestinal morphometry.

Nociceptin/Orphanin FQ (N/OFQ) Receptors are Involved in Adrenaline-Induced Feeding Behavior in Broiler Cockerels

Nociceptin/orphanin FQ (N/OFQ) is an endogenous ligand of a G protein-coupled receptornamed NOP. This neuropeptide has been identified as an orexigenic stimulus in the brain of birds and mammals. The purpose of the present study was to clarify whether blockade or stimulation of nociceptin receptors affects adrenaline-induced feeding behaviour in broilers. In Experiment 1, birds received intracerebroventricular (ICV) injection of Nociceptin (1–13) NH2 (potent NOP receptor agonist, 16 nmol) followed by adrenaline (80 nmol). In Experiment 2, the birds received UFP-101, (NOP receptor antagonist, 10 nmol) prior to injection of adrenaline (80 nmol). Cumulative food and water intake was measured at 2 h post-injection. When administrated alone, adrenaline significantly increased food and water intake. The ICV injection of Nociceptin (1–13) NH2 significantly increased food intake but not water intake. Pre-injection of Nociceptin (1–13) NH2 significantly increased the adrenaline-induced feeding response. The effect of adrenaline on food intake was transiently blocked by microinjection of UFP-101. UFP-101-induced anorexia was accompanied by a transient increase in water intake. The transient dipsogenic effect of UFP-101 suggests a role of endogenous N/OFQ-NOP receptor pathways in the regulation of water intake in chickens, which is food intake-independent. These results also provide further evidence for a reciprocal interaction between adrenergic receptors and N/OFQ on feeding behavior.

The effects of kaolin, bentonite and zeolite dietary supplementation on broiler chickens meat quality during storage

The experiment was conducted to determine the effects of broiler chickens dietary kaolin, bentonite and zeolite supplementations on broiler thigh meat water holding capacity (WHC), lipid oxidation (TBARS), pH, and meat color during frozen storage. A total of 448-dayold sexed broiler cockerels were randomly assigned into 28 experimental units. A cornsoybean meal basal diet with 0, 15 and 30 g/kg kaolin, bentonite and zeolite as feed additive were added to control and 6 dietary treatments. Chickens were slaughtered and the left thighs kept at −20°C and analyzed after 1 and 150 days of storage. Experimental treatments had no effect on meat WHC, pH and color. Freezing at −20°C for 150 days impaired meat quality and caused chicken rancidity; however, lipid oxidation measured by TBARS value was significantly lower in chickens received diets including 15 g/kg bentonite and kaolin comparing to control diet after 150 days of frozen storage (P&amp;lt;0.05). It was concluded that though adding silicate minerals did not significantly influence WHC, pH and color in experimental treatments, they had influenced lipid oxidation and decreased chicken meat rancidity during frozen storage period

Efficacy of avilamycin for the prevention of necrotic enteritis caused by a pathogenic strain of Clostridium perfringens in broiler chickens

ABSTRACTThe efficacy of avilamycin for the prevention of necrotic enteritis (NE) was investigated in a 35-day floor pen study of 2200 broiler cockerels using a Clostridium perfringens (Cp) feed inoculum challenge model. Treatments consisted of (1) nonmedicated, nonchallenged; (2) nonmedicated, challenged; (3) avilamycin at 15 ppm, challenged; (4) avilamycin at 30 ppm, challenged. Avilamycin was administered in the feed from day 7 to day 30 of the study. Challenge inoculum was administered on day 14 and delivered approximately 109 CFU Cp/bird. NE mortality rates from day 14–35 were significantly (P < 0.0001) lower in birds treated with avilamycin at 15 and 30 ppm when compared to nonmedicated, challenged birds. Treatment with avilamycin also resulted in a significant reduction in ileal Cp count on day 21 (P < 0.0001) and NE lesion scores on day 17 (P < 0.006) when compared to nonmedicated, challenged birds. The performance of birds treated with avilamycin was also improved when compared to nonmedicated, challenged birds. Cockerels that received either 15 or 30 ppm avilamycin had a significantly (P < 0.0001) increased body weight on day 35 and average daily gain from days 0–35 than nonmedicated, challenged birds. Furthermore, birds treated with avilamycin had an improved feed conversion rate from days 0–35 compared to both nonmedicated, nonchallenged birds and nonmedicated, challenged birds. This study confirms that avilamycin is effective at controlling mortality related to NE in growing broiler chickens.

Involvement of Central β-Adrenergic Circuitry in Food and Water Intake in Chickens

We examined the effects of intracerebroventricular (i.c.v.) microinjections of a β1,2-adrenergic agonist, isoproterenol (ISOP), and of a β1,2-adrenoceptor blocker, propranolol (PROP), on food and water intake in broiler cockerels deprived of food and water for 3 h. We found that ISOP, at a 200 nM concentration and not smaller, significantly (P ≤ 0.05) increased food intake but not water intake. PROP microinjected in different doses (20–80 mM) significantly (P ≤ 0.05) decreased food intake. These observation suggest a direct orexigenic role for the β1- and β2-adrenergic systems in the regulation of food intake in chickens. The significant (P ≤ 0.05) effect of i.c.v. injections of PROP (transient increase in water intake) implies a role of the adrenergic system, possibly via α-adrenoceptors, in the regulation of water intake in broilers, which is food intake-independent.

The Effect of Histaminergic System on Nociceptin/Orphanin FQ Induced Food Intake in Chicken

The present study was designed to examine the effects of intracerebroventricular injection of para-chlor- ophenylalanine (PCPA) (cerebral serotonin depletive), fluoxetine (selective serotonin reuptake inhibitor), 8-OH- DPAT (5-HT1A autoreceptor agonist) and SB 242084 (5-HT2c receptor antagonist) on nociceptin/orphanin FQ (N/OFQ) induced feeding response in chickens. A guide cannula was surgically implanted into the lateral ventricle of chickens. Before the experiments, 3-h fasting periods had been given to all experimental birds. In experiment 1, chickens were injected with PCPA (1.5 lg) followed by an N/OFQ injection (16 nmol) intracerebroventricularly. In experiment 2, birds received fluoxetine (10 lg) prior to the injection of N/OFQ. In experiment 3, chickens were administered with N/OFQ after the 8-OH-DPAT adminis- tration (15.25 nmol). In experiment 4, birds were injected with SB 242084 (1.5 lg) followed by an N/OFQ injection. Cumulative food intake was measured at 3 h post injection. The results of this study show that N/OFQ increases food intake in broiler cockerels (P \ 0.05) and that this effect is amplified by pretreatment with PCPA and SB 242084 in an additive manner (P \ 0.05). The effect of N/OFQ is not changed by pretreatment with 8-OH-DPAT (P ( 0.05). Furthermore, the stimulatory effect of N/OFQ on food intake was significantly attenuated by pretreatment with fluoxetine. These results suggest that N/OFQ induced hyperphagia is mediated by serotonergic mechanisms, and possibly imply an interaction between N/OFQ and the serotonergic system (via 5-HT2C receptors) on food intake in chickens.

Ghrelin-induced hypophagia is mediated by the β2 adrenergic receptor in chicken.

The purpose of this study was to examine the effects of intracerebroventricular injection of metoprolol (a β1 adrenergic receptor antagonist), ICI 118,551 (a β2 adrenergic receptor antagonist), and SR 59230R (a β3 adrenergic receptor antagonist) on ghrelin-induced food and water intake by 3-h food-deprived (FD3) cockerels. The chickens were randomly allocated to 4 treatment groups with 8 replicates in each group. A cannula was surgically implanted into the lateral ventricle of the brain. In experiment 1, chickens received the β1 adrenergic receptor antagonist (24 nmol) before injection of the ghrelin (0.6 nmol). In experiment 2, chickens received the β2 adrenergic receptor antagonist (5 nmol) before injection of the ghrelin (0.6 nmol). In experiment 3, birds were injected with ghrelin (0.6 nmol) after the β3 adrenergic receptor antagonist (20 nmol). Cumulative food and water intake were recorded 3-h post injection and analyzed by two-way analysis of variance. According to the results, ghrelin injection reduced food and water intake by broiler cockerels (p≤0.05). The effect of ghrelin on food intake was significantly attenuated by pretreatment with the β2 receptor antagonist (p≤0.05). Furthermore, the β2 receptor antagonist had no effect on water intake induced by ghrelin. Also, pretreatment with the β1 and β3 receptors antagonists had no effect on ghrelin-induced food and water intake. These results suggest that the effect of ghrelin on cumulative food intake by cockerels is mediated via β2 adrenergic receptors.

The effect of serotonergic system on nociceptin/orphanin FQ induced food intake in chicken

The present study was designed to examine the effects of intracerebroventricular injection of para-chlorophenylalanine (PCPA) (cerebral serotonin depletive), fluoxetine (selective serotonin reuptake inhibitor), 8-OH-DPAT (5-HT1A autoreceptor agonist) and SB 242084 (5-HT2c receptor antagonist) on nociceptin/orphanin FQ (N/OFQ) induced feeding response in chickens. A guide cannula was surgically implanted into the lateral ventricle of chickens. Before the experiments, 3-h fasting periods had been given to all experimental birds. In experiment 1, chickens were injected with PCPA (1.5μg) followed by an N/OFQ injection (16nmol) intracerebroventricularly. In experiment 2, birds received fluoxetine (10μg) prior to the injection of N/OFQ. In experiment 3, chickens were administered with N/OFQ after the 8-OH-DPAT administration (15.25nmol). In experiment 4, birds were injected with SB 242084 (1.5μg) followed by an N/OFQ injection. Cumulative food intake was measured at 3h post injection. The results of this study show that N/OFQ increases food intake in broiler cockerels (P<0.05) and that this effect is amplified by pretreatment with PCPA and SB 242084 in an additive manner (P<0.05). The effect of N/OFQ is not changed by pretreatment with 8-OH-DPAT (P>0.05). Furthermore, the stimulatory effect of N/OFQ on food intake was significantly attenuated by pretreatment with fluoxetine. These results suggest that N/OFQ induced hyperphagia is mediated by serotonergic mechanisms, and possibly imply an interaction between N/OFQ and the serotonergic system (via 5-HT2C receptors) on food intake in chickens.

The effect of melanocortin (Mc3 and Mc4) antagonists on serotonin-induced food and water intake of broiler cockerels

The current study was designed to examine the effects of intracerebroventricular injections of SHU9119 [a nonselective melanocortin receptor (McR) antagonist] and MCL0020 (a selective McR antagonist) on the serotonin-induced eating and drinking responses of broiler cockerels deprived of food for 24 h (FD24). For Experiment 1, the chickens were intracerebroventricularly injected with 2.5, 5, and 10 µg serotonin. In Experiment 2, the chickens received 2 nmol SHU9119 before being injected with 10 µg serotonin. For Experiment 3, the chickens were given 10 µg serotonin after receiving 2 nmol MCL0020, and the level of food and water intake was determined 3 h post-injection. Results of this study showed that serotonin decreased food intake but increased water intake among the FD24 broiler cockerels and that these effects occurred in a dose-dependent manner. The inhibitory effect of serotonin on food intake was significantly attenuated by pretreatment with SHU9119 and MCL0020. However, the stimulatory effect of serotonin on water intake was not altered by this pretreatment. These results suggest that serotonin hypophagia and hyperdipsia were mediated by different mechanisms in the central nervous system, and that serotonin required downstream activation of McRs to promote hypophagia but not hyperdipsia in the FD24 chickens.

The effect of tannic acid and polyethylene glycol on the absorption capacity of chicken intestine for d‐xylose and β‐carotene

In an experiment, the possible influence of tannic acid (TA) and polyethylene glycol (PEG) on the absorption capacity of intestine for d-xylose and β-carotene in broiler chicken was investigated. Four groups of nine 28-day-old broiler cockerels received d-xylose (500 mg) and β-carotene (52 μg) solutions (Group 1 to 4) with TA (1 g, Group 2 to 4) and PEG (500 mg Group 3 and 1 g Group 4), orally. One blood sample prior to, and four others after the administration of test materials, were collected from wing vein on 40 min basis, for 160 min and the concentration of plasma d-xylose was determined. The concentration of β-carotene was also measured in plasma of blood samples taken prior to and 160 min post-administration of the test materials. Plasma d-xylose concentration of all groups showed quadratic correlations with time (p < 0.001, r(2) = 0.84, 0.60, 0.70 and 0.74 for Group 1 to 4, respectively). Administration of TA reduced the plasma concentration of d-xylose in Group 2. However, feeding PEG after TA raised the concentration of d-xylose in Group 4 to the level that there was no difference in that variable between this group and Group 1. Although the plasma concentration of β-carotene was increased in 160 min post-ingestion of the test material, no difference was found in that variable among the experimental groups. In conclusion, TA and its interaction with PEG have impacts on the absorption capacity of intestine for d-xylose and highly likely other simple sugars, but TA or PEG have no influence on the absorption of β-carotene and most probably other fat soluble vitamins.

The effects of DL-AP5 and glutamate on ghrelin-induced feeding behavior in 3-h food-deprived broiler cockerels

This study was designed to examine the effects of intracerebroventricular injection of DL-AP5 (N-methyl-D-aspartate (NMDA) receptor antagonist) and glutamate on ghrelin-induced feeding behavior in 3-h food-deprived (FD3) broiler cockerels. At first, guide cannula was surgically implanted in the right lateral ventricle of chickens. In experiment 1, birds were intracerebroventricularly injected with 0, 2.5, 5, and 10 nmol of DL-AP5. In experiment 2, chickens received 5 nmol DL-AP5 prior to the injection of 0.6 nmol ghrelin. In experiment 3, birds were administered with 0.6 nmol ghrelin after 300 nmol glutamate, and the cumulative feed intake was determined at 3-h postinjection. The results of this study showed that the intracerebroventricular injection of DL-AP5 increased food consumption in FD3 broiler cockerels (P ≤ 0.05), and this increase occurs in a dose-dependent manner. Moreover, the decreased food intake induced with the intracerebroventricular injection of ghrelin was additively enhanced by pretreatment with glutamate, and this effect was attenuated by DL-AP5 administration(P ≤ 0.05).These results suggest that there is an interaction between ghrelin and glutamatergic system (through NMDA receptor) on food intake in broiler cockerels.

Effects of different levels of dietary supplemental caprylic acid and vitamin E on performance, breast muscle vitamin E and A, and oxidative stability in broilers

The paper reports data from four experiments (EXP). Broiler cockerels Ross 308 were allocated to 3 or 5 (EXP 4) dietary treatments comprising 300 (3 replicated pens of 100 chicks per pen), 50, 50&amp;nbsp;or 100&amp;nbsp;chickens. The EXP lasted 42, 38, 42 and 38 days. All basal diets contained adequate ingredients. The inclusion of 0.5% caprylic acid (CA) in diets reduced (&lt;I&gt;P &lt;/I&gt;&amp;lt; 0.05) body weight (EXP 1). The results of EXP 3 and 4 indicated that the diet supplemented with 0.25% CA and 30 mg vitamin E (total vitamin E concentration 50&amp;nbsp;mg) resulted in similar BW like the basal diet, but the increased supplemental vitamin E to 150 mg (EXP 3) or to 100 mg (EXP 4) decreased (&lt;I&gt;P &lt;/I&gt;&amp;lt; 0.05 and &lt;I&gt;P &lt;/I&gt;&amp;lt; 0.001) BW and increased mortality. No differences were found between the fat and crude protein contents in dry matter of breast meat. Higher vitamin E doses in feed mixture significantly (&lt;I&gt;P &lt;/I&gt;&amp;lt; 0.001) increased the content of vitamins soluble in fats in breast meat – vitamin E (from 28.54 in the control to 80.28&amp;nbsp;mg/kg of dry matter) and vitamin A (from 0.34 to 0.44 mg/kg of dry matter). The&amp;nbsp;addition of caprylic acid significantly decreased the speed of lipid oxidation measured after 3&amp;nbsp;(&lt;I&gt;P &lt;/I&gt;&amp;lt; 0.02) and 5 (&lt;I&gt;P &lt;/I&gt;&amp;lt; 0.05) days of storage in refrigerator at a temperature from 2.5 to 4°C. On the contrary, higher vitamin E doses and basal diet without CA supplement increased the oxidation of lipids.

Intralateral hypothalamic area injection of isoproterenol and propranolol affects food and water intake in broilers

The role played by adrenergic system in water intake, especially food intake, has long been known in mammals. In avian species, there have been many experiments exploring the effects of the adrenergic system in different sites in the central nervous system in meat- and egg-type poultry. This study was designed to examine the possible effects of intralateral hypothalamic area (ILHy) microinjections of a beta-adrenergic agonist, isoproterenol, and a beta-adrenoceptor blocker, propranolol, on food and water intake in 3-h food-deprived and 3-h water-deprived broiler cockerels. Our findings suggest that the beta-adrenergic system directly affects food especially water intake in broilers. Although isoproterenol significantly (P < or = 0.05) decreased food intake for the first 15 min, it reduced food intake during the experiment. Isoproterenol reduced water intake significantly (P < or = 0.05), which was abolished by pretreatment with propranolol. It is proposed that beta-adrenoceptors in LHy play a direct and indirect role in the regulation of food especially water intake in broiler cockerels.

D-Xylose absorption capacity of broiler intestine in response to phytic acid

1 Dietary phytic acid (PA) reduces the apparent digestion and of dietary nutrients, increases the excretion of endogenous amino acids and minerals and reduces the concentration of blood glucose. 2 An experiment was conducted to examine the effect of phytic acid on the absorption capacity of the intestine in broiler chicken, using a D-xylose absorption test. 3 Three groups of ten 26-d-old apparently healthy broiler cockerels (Ross 308) were dosed with D-xylose solution (500 mg/kg BW, Group 1) or D-xylose solution + PA (330 or 660 mg/5 ml/bird, in groups 2 and 3), respectively. The plasma concentration of D-xylose was measured at 40-min intervals after ingestion of test materials, for a total of 160 min. 4 There was a quadratic correlation between the concentration of plasma D-xylose and time in all experimental groups (P < 0⋅001, R 2= 0⋅78, 0⋅80 and 0⋅81 for groups 1–3, respectively). Ingestion of PA at 660 mg reduced the concentration of plasma D-xylose by 21⋅6 and 10⋅5% at 40 and 80 min after ingestion of the test material, indicating a lower absorption of this sugar. 5 It was concluded that dietary phytates might affect the productive performance of chicken, at least partly, by disturbing the transport mechanisms involved in the absorption of nutrients.

The effects of bicuculline and muscimol on glutamate-induced feeding behavior in broiler cockerels

This study was designed to examine the effects of intracerebroventricular (ICV) injection of bicuculline (GABA(A) receptor antagonist) and muscimol (GABA(A) receptor agonist) on glutamate-induced eating response in 24-h food-deprived (FD24) broiler cockerels. At first, guide cannula was surgically implanted in the right lateral ventricle of chickens. In experiment 1, birds were ICV injected with different doses of glutamate. In experiment 2, birds were administered with effective dose of glutamate after bicuculline. In experiment 3, chickens received muscimol prior to the injection of glutamate, and cumulative food intake was determined at 3-h postinjection. The results of this study showed that glutamate decreases food consumption in FD24 broiler cockerels (P <or= 0.05), and this reduction occurs in a dose-dependent manner. Moreover, the inhibitory effect of glutamate on food intake was significantly increased with bicuculline pretreatment, and this effect was attenuated with muscimol (P <or= 0.05). These results suggest that there is an interaction between glutamatergic and GABAergic systems (through GABA(A) receptor) on food intake in broiler cockerels.

Influence of tannic acid and polyethylene glycol on the excretion and digestibility of amino acids in gelatin-fed broilers

1. A precision feeding experiment was conducted to evaluate the effects of tannic acid (TA) and polyethylene glycol (PEG) on the excretion of amino acids, and the apparent and true digestibility of gelatin protein in broilers. 2. In a 3 × 2 × 2 factorial design, ninety-six 7-week-old broiler cockerels in 8 replicates of 12 treatments, were fed on warm solution of gelatin alone (0, 6 or 12 g/50 ml/bird, Treatments 1–3), or gelatin with TA solution (4·5 g TA/10ml/bird, Treatments 4–6) and PEG solution (2 g/10 ml/bird, Treatments 7–12). Total excreta were collected for 48 h and the amino acid contents of gelatin and excreta were determined. 3. In the absence of TA, the digestibility of gelatin was almost complete. TA increased the excretion of amino acids from gelatin-fed birds to varying extents. Although the digestibility of all indispensable and dispensable amino acids was adversely affected by the presence of TA, increasing the amount of gelatin from 6 to 12 g improved the apparent and true digestibility of amino acids. PEG reduced the excretion of amino acids and improved the digestibility of amino acids in gelatin in TA-dosed birds. However, the effect was greater when the lesser amount of gelatin was fed. 4. In conclusion, PEG seemed to play an important role in reducing the effect of dietary tannins in the gastrointestinal tract of birds fed on diets high in tannins and improved protein digestibility and utilisation, particularly when the diet was low or marginal in protein.