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Pam3cys is a weak agonist of toll-like receptors type 1 and 2 and is able to inhibit learning and memory impairment in an animal model of Alzheimer's disease by inhibiting the secretion of inflammatory cytokines and increasing the secretion of anti-inflammatory cytokines. This arrangement is effective in improving memory performance. Considering the improving effect of Pam3cys on learning and memory impairment of Alzheimer's disease in an animal model, in this study, the effect of Pam3cys drug alone on the spatial memory of rats was investigated

In this experimental study, 48 male Wistar rats (age, 45-days old; weight, 220-270 g) were randomly divided into six groups (n = 8) as follows: There were two control groups of 7 and 28 days, two sham groups of 7 and 28 days, and two drug groups of 7 and 28 days. The spatial memory learning process of all mice was done using the Morris water maze for five days and four training sessions every day to find the hidden platform. At the last day of the learning period, the drug was injected intraventricularly with phosphate buffer (sham group) or Pam3cys (1 μg/5μl per mouse). 7 and 28 days after the injection, the memory of the rats was measured by measuring the time, speed and distance traveled in the target quarter of the maze.

In the learning phase, there was no significant difference between the groups in terms of the time spent and the distance traveled in the target quarter of the circle. At 7 and 28 days after the learning period, there was no significant difference between the groups in terms of memory recall between the group of animals that received Pam3cys and the group of control animals as well as sham animals without receiving the drug (p > 0.05).

Pam3cys with the dose used in this study has no effect on the spatial memory performance of rats in the short and long term. Also, due to the lack of effect on healthy rats, it can be used as a safe medicine in disease conditions.

The importance of the reproduction process in the continuation of the human race and the increase in livestock production has prompted researchers to conduct extensive research with the aim of identifying the factors and compounds affecting reproductive efficiency. In this regard, in the current study, we investigate the effects of melatonin and zinc administration separately or together on estrogen hormone levels and ovarian follicular parameters in female rats.

A total of 35 adult female rats were distributed in a completely randomized design with 5 treatments, 7 repetitions and placing two mice in each cage and were treated by gavage in the opposite order for 20 days: control group-1: Base diet, control group-2: normal saline, treatment group-1: zinc (40 ppm), treatment group-2: melatonin (5 mg/kg) and treatment group-3: melatonin + zinc. After performing these steps, serum and ovarian tissue sections of the samples were evaluated in terms of hormonal and histopathological changes.

Based on the findings, in the melatonin + zinc group, the average diameter of granulosa cells increased significantly compared to the control groups (P<0.05). Also, the average diameter of mature follicles and the average number of antral follicles in rats receiving melatonin increased significantly compared to the control groups (P<0.05). However, the administration of zinc and melatonin alone or separately did not have a significant effect on estrogen hormone levels (P≤0.05).

The results obtained from this study showed that administration of melatonin alone or in combination with zinc improves ovarian follicular parameters in female rats, but has no effect on estrogen hormone levels.

Orexin is a neuropeptide that is localized mainly to neurons within and around the lateral hypothalamus and binds to two orexin receptors type 1 and 2. The presence of orexinergic neurons in the accumbens area has also been proven. Previous studies have shown the role of orexin in the dorsal raphe nucleus and hippocampus in learning and memory processes, but so far no study has focused on the effects of orexin in the accumbens area on memory. In the present study, the role of orexin 1 and 2 receptors in the accumbens area on consolidation and retrieval of passive avoidance memory in rats was investigated. For this purpose, 24 Wistar rats were prepared and 4 experiments were designed and performed in the shuttle box environment. After training, the test groups of each experiment were injected with control solution (DMSO), type 1 orexin receptor antagonist (SB334867-A) and type 2 orexin receptor antagonist (TCS-OX2-29) through a cannula into the accumbens area. The results showed that in the passive avoidance memory consolidation phase, the administration of SB334867-A significantly reduced the duration of staying in the light part and the first time to enter the dark part of the box compared to the control group (p<0.05), while Administration of TCS-OX2-29 did not have a significant effect (p>0.05). In the passive avoidance memory retrieval phase, the administration of SB334867-A and TCS-OX2-29 did not cause a significant change in the duration of staying in the light part and the first time of entering the dark part of the box (p>0.05). According to the results, it is possible that the functional deletion of type 1 orexin receptor affects and disrupts the process of passive avoidance memory consolidation.

Years of research on the physiological pathways that regulate appetite have led to the identification of dozens of neural mediators involved in this process. Based on these studies, the role of histaminergic and adrenergic systems in regulating food intake has been proven. The aim of the current study is to investigate the central synergistic effects of histamine and adrenaline on food intake and plasma cortisol in broiler chickens.

In order to achieve this goal, three experiments were designed, each including one control group and three treatment groups. In the first test, control solution and histamine were prescribed with doses of 75, 150, and 300. In the second test, the control solution and adrenaline were injected with doses of 75, 150, and 300 nmol, and in the third test, in addition to the control solution, histamine (75 nmol), adrenaline (75 nmol) and histamine + adrenaline were injected. Then, chickens were returned to their cages and their food intake was recorded as a percentage of body weight. After the end of the experiments, by cutting the head, blood was taken and the plasma cortisol level was evaluated in all groups.

Based on the findings, simultaneous administration of sub effective doses of histamine and adrenaline caused a significant decrease in food intake (P≤0.05) and a significant increase in plasma cortisol levels (P≤0.01).

According to the results, it seems that there is a synergistic effect between histamine and adrenaline in controlling food intake and plasma cortisol levels

The present study was conducted with the aim of investigating the synergistic effects of CCK and glutamate on feeding behavior in layers. For this purpose. In the first experiment, the control solution, CCK4 (1 nmol), glutamate (75 nmol), and CCK4 + glutamate were injected intracerebroventricularly (ICV). The second experiment was performed according to the first experiment, with the difference that glutamate was injected with an effective dose (300 nmol). In the third experiment, the control solution, CCK8s (0.125 nmol), glutamate (75 nmol), and CCK8s + glutamate were administered. The fourth experiment was also the same as the third experiment and only the doses of CCK8s (1 nmol) and glutamate (300 nmol) were changed. According to the obtained results, the administration of doses under the effect of CCK4 and glutamate separately or simultaneously did not have a significant effect on the food intake of chickens (p<0.05). Injection of an effective dose of glutamate led to a significant decrease in feed intake, and simultaneous administration of CCK4 with glutamate did not change this hypophagic effect (p<0.05). Injection of sub-effective doses of CCK8s and glutamate had no significant effect on food intake (p<0.05), however, their simultaneous administration weakened food intake (p<0.05). Injection of effective doses of CCK8s and glutamate separately caused a significant decrease in food intake in chickens, and the administration of both of them strengthened this hypophagic effect (p<0.05). Finally, it seems that there is a synergistic effect between CCK8s and glutamate in the regulation of food intake in laying chickens.

The dopaminergic system plays an important role in modulating some neural functions such as motor control, motivation, pain, cognition, maternal behavior, and reward. Dopaminergic signaling pathways are very important for maintaining physiological processes, and an unbalanced activity may lead to disorders related to neurological diseases. A correct understanding of the neurobiology and underlying molecular mechanisms of these disorders leads to the development of new treatments that improve the quality of life of patients all over. The purpose of the present study is to review the research conducted on the central role of the dopaminergic system and the dimensions of its influence on various physiological functions. In this review, articles related to the topic in the years 1970 to 2023 were identified using a targeted search of related keywords in reliable databases such as Civilica, Web of Science, Scopus, Science Direct, PubMed, Springer, Google Scholar, and Elsevier, and in order to obtain more studies from the list The sources of these articles were used. Based on the findings of these studies, the appetite-reducing effects of dopamine have been reported in birds and mammals. On the other hand, the role of this neural mediator in pain perception and memory processing was determined. In connection with the endocrine glands, the interaction of dopamine with prolactin, sex steroids, growth hormone, and thyroid hormones has been proven. Also, numerous studies have shown the role of dopamine in motor control and the occurrence of maternal behavior. Finally, based on the review of past research, the occurrence of neurological diseases such as schizophrenia, Parkinson, Huntington, attention deficit/hyperactivity disorder (ADHA), and addiction can be related to abnormalities in the dopaminergic system. Despite conducting numerous studies on the role of the dopaminergic system in various biological activities, it is suggested to carry out more studies in order to identify new dimensions of the effect of this system on different body functions and to provide new treatment paths.
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Catamenial epilepsy is a special form of epilepsy in women whom seizure aggravation is arranged with menstrual cycle that may affect up to 70 % of epileptic women. According to earlier studies, the role of neuropeptide Phoenixin (PNX) in the reproductive system has been observed and its antiepileptic effects have been proven. It also appears that the GABAergic system plays an important role in inhibition of seizures. Therefore, the aim of this study was to investigate the central effects of PNX and muscimol (GABA-A receptor agonist) on Pentylenetetrazol (PNT)-induced seizures during various stages of the estrous cycle among rats.

In this study, 120 adult female rats were randomly divided into five groups, including intracerebroventricular (ICV) injection of normal saline, PNX (5 μg), PNX (10 μg), muscimol (0.1 μg)+ PNX (5 μg) and muscimol (0.1 μg)+ PNX (10 μg), in proestrus, estrus, metestrus, and diestrus. After ICV injections, acute epilepsy was induced by intraperitoneal (IP) injection of 80 mg/kg of pentylentetrazole. Initiation time of myoclonic seizures (ITMS) and initiation time of tonic–clonic seizures (ITTS) were monitored and recorded for 30 min.

The results of the present study showed that PNX alone increased both ITMS and ITTS in all phases of estrus (p<0.05). Furthermore, the injection of PNX with muscimol significantly reinforced the effects of the PNX on ITMS and ITTS in all estrus stages (p<0.05).

The results showed that the antiepileptic activity of PNX was probably mediated by GABA-A receptors.

Appetite modulation includes a set of complex physiological mechanisms that affect different areas of the central nervous system. Previously, the role of dopaminergic and melanocortinergic systems in the central control of food intake in birds has been proven. The current study was conducted with the aim of investigating the synergistic effects of dopaminergic system and melanocortinergic system on feeding behavior in layer chickens. In this study, three experiments were designed, so that each experiment included one control group and three treatment groups(n=12 in each group). In all groups, birds received intracerebroventricular injection of diluent solution or drug solution after 3 hours of food deprivation. In the first experiment, in order to determine the sub-effective dose of dopamine, normal saline and dopamine were injected with doses of 10, 20 and 40 nmol respectively in the test groups. In the second experiment, normal saline, L-dopa (dopamine precursor, 250 nmol), MTII (2.45 pmol, MC3/4 receptor agonist) and L-dopa + MTII were injected, and the third experiment was conducted as second experiment, but instead of L-dopa, dopamine (10 nmol) was injected either alone or in combination with MTII. After the injection, water and food were freely available to the birds and food consumption (gr) was measured based on the percentage of body weight. Based on the obtained results, the dose of 10 nmol of dopamine was determined as the sub-effective dose. It was also observed that the injection of sub-effective doses of dopamine, L-dopa and MTII alone had no effect on the food intake of chickens (p > 0.05), and only co-injections of L-dopa + MTII and dopamine + MTII caused a significant decrease in food intake in chickens (p<0.05). Based on the findings, it seems that there is probably a synergistic effect between the dopaminergic system and the melanocortinergic system in the control of food intake in chickens.

Appetite modulation is a set of complex physiological mechanisms affecting different central nervous system areas. Glutamate and histamine play an important role in the central control of food intake in birds and reduce food intake in birds. The present study was conducted to investigate the synergistic effects of central glutamatergic and histaminergic systems on feeding behavior in neonatal chicks. 36 chickens were randomly divided into three experimental groups. Each experiment included a control group and 3 treatment groups (12 chickens in each group). In all experiments, after 3 hours of food deprivation (FD3), chicks received either control diluent or drug solution by intracerebroventricular (ICV) injection. Then the birds had ad libitum access to the ‎food and fresh water, and then cumulative food intake (gr) was measured based on the ‎percentage of the body (%BW) ‎. In the first experiment, glutamate (75 nmol), histamine (75 nmol), and histamine + glutamate was injected. In the second experiment, chlorpheniramine (H1 receptor antagonist, 300 nmol), MK-801 (NMDA glutamate receptor antagonist, 15 nmol), and chlorpheniramine + MK-801 was injected. In the third experiment, MK-801, α-FMH (histamine synthesis inhibitor, 250 nmol), and α-FMH + MK-801 was injected. The results showed that the injection of sub-effective doses of histamine with a dose of 75 nmol (sub-effective dose) and glutamate with a dose of 75 nmol (sub-effective dose) did not affect food intake (p > 0.05). However, co-injection of glutamate and histamine decreased food intake (p < 0.05). Injection of chlorpheniramine with a dose of 300 and MK-801 with a dose of 15 had no effect on food intake (p > 0.05). However, co-injection of chlorpheniramine and MK-801 increased food intake (p < 0.05). Injection of α-FMH with a dose of 250 and MK-801 with a dose of 15 did not influence food intake (p > 0.05). However, co-injection of α-FMHs and MK-801 increased food intake (p < 0.05). According to the results, there is probably a synergistic effect between histaminergic and glutamatergic systems in the control of food intake in neonatal chicks.

The opioidergic system and its different receptors play an important role in the central control of food intake in birds. On the other hand, the decreasing effect of oxytocin on food intake of birds has been observed. The present study was conducted to investigate the synergistic effects of oxytocin with opioid receptors on food intake in neonatal layer chickens.

In this study, three experiments were designed, so that each experiment included one control group and three treatment groups. In all groups, birds received intracerebroventricular injection of diluent solution or drug solution after 3 hours of food deprivation. In the first experiment, normal saline, oxytocin(0.16 nmol), DAMGO(62.5 picomol) (agonist of mu-opioid receptors) and oxytocin plus DAMGO were injected. The other experiments were conducted as experiment 1, but instead of DAMGO, DPDPE (20 nmol)(agonist of delta opioid receptors) in the experiment 2 and U-50488H (10 nmol)(agonist of kappa opioid receptors) in experiment 3 were injected either alone or in combination with oxytocin. After the injection, water and food were freely available to the birds and then cumulative food intake (gr) was measured based on the ‎percentage of the body weight.

The results of the present study showed that sub effective dose injection of oxytocin plus DAMGO significantly reduced food intake in layer chickens (P<0.05).

According to the results of the present study, there is probably a synergistic effect between oxytocin with mu-opioid receptors agonist on food intake control of neonatal layer chicks.

Dopamine and noradrenaline  play an important role in food intake control. On the other hand, neuromedin S (NMS) decreases food intake. This study aimed to investigate the synergistic effects of dopamine and noradrenaline  with a sub-effective dose of NMS on food intake in neonatal chickens.

A total of 132 five-old-day chicks were randomly divided into three experimental groups. Each experiment had a control group and three treatment groups (n = 11 in each group). Three-hour food-deprived birds received intracerebroventricular ‎injections of either control diluent or drug solution. In the first experiment, control solution, NMS (0.25 nmol), L-DOPA (dopamine precursor; 125 nmol), and NMS + L-DOPA were injected.‎  In the second experiment, control solution, NMS (0.25 nmol), dopamine (10 nmol), and NMS + dopamine were injected. In the third experiment, control solution, NMS (0.25 nmol), noradrenaline (37.5 nmol), and , NMS + noradrenaline were injected.

Although the injection of NMS with a dose of 0.25 (sub-effective dose), L-dopa with a dose of 125 (sub-effective dose), dopamine with a dose of 10 (sub-effective dose), and noradrenaline with a dose of 37.5 (sub-effective dose) had no effect on food intake (p < 0.05), the co-injection of Neuromedin S with L-dopa or dopamine or noradrenaline decreased food intake (p < 0.05).

According to the results of the present study, there is probably a synergistic effect between NMS with dopamine and noradrenaline on food intake control of neonatal chicks.

5-Hydroxytryptamine or serotonin is a biogenic amine that is best known for its function as a neurotransmitter. One of the most important effects of serotonin is its role in regulating food intake. Further understanding of the serotonergic mechanisms affecting food consumption, in addition to improving animal production, can lead to effective serotonin-based drug treatments to help modulate appetite in humans. The purpose of this review is to examine the research conducted on the role of the serotonergic system (except for the interference of its effect with other systems) in the process of obtaining food. In the present study, according to PRISMA guidelines, articles related to the topic were identified using a systematic search of standard keywords in reliable databases such as Web of Science, Scopus, Science Direct, PubMed, Springer, Google Scholar, and Elsevier in the period of 1990-2022. In order to obtain more studies, the list of sources of these articles was examined. Finally, 40 articles that met all the conditions for entering the analytical stage were examined. Based on the findings of these studies, serotonin in birds and mammals reduces food intake. Serotonin reuptake inhibitor compounds also cause hypophagia and serotonin receptor agonists and antagonists have different effects on the appetite process. It also seems that 5HT1A, 5HT1B and 5HT2C receptors have the most interaction in the process of appetite modulation. Considering the diversity of serotonin receptors and the distribution of this system in different central and peripheral areas in order to know its role in regulating food intake, it is necessary to carry out more research in this field.
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Feeding behavior is regulated via a complex network which interacts via diverse signals from central and peripheral tissues. The present study was designed to examine the interaction between glutamatergic and dopaminergic systems on food intake in neonatal meat chicken.

In this study, 264 day-old chicken (ROS 308) were used. In each experiment, chickens divided to 4 experiments including 1 control and 3 treatment groups (n = 11). In experiment 1, chicks ICV injected with normal saline, 6-OHDA (neurotoxin, 2.5 nmol), kainic acid (ionotropic glutamate receptors agonist, 300 nmol) and 6-OHDA + kainic acid. Experiments 2-3 were similar to experiment 1, except injections of the SHC23390 (D1 receptors antagonist, 5 nmol) and AMI-193 (D2 receptors antagonist, 5 nmol) were done instead of 6-OHDA. In experiment 4, saline, 6-OHDA (2.5 nmol), trans-(±)-ACPD monohydrate (metabotropic glutamate receptor agonist, 300 nmol) and co-injection of the 6-OHDA+ trans-(±)-ACPD monohydrate were done. Experiments 5 and 6 were similar to experiment 4, except SHC23390 and AMI-193  were injected instead of 6-OHDA. Then the cumulative food intake measured until 120 min post injection.

Kainic acid significantly decreased food intake (p ≤ 0.05). 6-OHDA and SHC23390 decreased kainic acid and trans-(±)-ACPD- induced hypophagia (p ≤ 0.05).

Interaction between dopaminergic and glutamatergic systems mediates via ionotropic and metabotropic glutamate and D1 dopamine receptors.
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Food intake is a set of physiological mechanisms affecting different central nervous system areas. The melanocortin system plays an important role in the central control of food intake in birds. Nesfatin-1 reduces food intake in birds. The present study was conducted to investigate the effect of the melanocortin system on food intake caused by nesfatin-1 in broiler chickens. 36 broilers were randomly divided into three experimental groups. Each experiment included a control group and 3 treatment groups (12 chickens in each group). In all experiments, after 3 hours of food deprivation (FD3), chicks received either control diluent or drug solution by intracerebroventricular (I.C.V.) injection. Then the birds had ad libitum access to the ‎food and fresh water, and then cumulative food intake (gr) was measured based on the ‎percentage of the body (%BW). In the first experiment, chickens in the first group were given the control solution, the second group nesfatin-1 (40 ng), the third group SHU9119 (0.5 nmol, antagonist of MC3/MC4 receptors), and the fourth group nesfatin-1 + SHU9119 intracerebroventricularly was injected. In the second experiment, chickens in the first group were injected with the control solution, the second group with nesfatin-1 (40 ng), the third group with MCL0020 (0.5 nmol, MC4 receptor antagonist), and the fourth group with nesfatin-1+ MCL0020. In the third experiment, chickens in the first group were injected with the control solution, the second group with nesfatin-1 (10 ng), the third group with MTII (2.45 pmol, an agonist of MC3/MC4 receptors), and the fourth group with nesfatin-1+ MTII. The results showed that the injection of nesfatin-1 with a dose of 40 ng decreased food intake (p<0.05). Co-injection of nesfatin-1 and SHU9119 and co-injection of nesfatin-1 and MCL0020 inhibited the hypophagia caused by nesfatin-1 (p < 0.05). Injection of Nesfatin-1 with a dose of 10 ng and MTII with a dose of 2.45 pmol did not affect food intake (p > 0.05). While the co-injection of nesfatin-1 with a dose of 10 ng and MTII with a dose of 2.45 pmol reduced food intake (p < 0.05). According to the results, food intake caused by nesfatin-1 in broilers is probably mediated by the melanocortin system.

Appetite modulation is a set of physiological mechanisms that influence the various areas of the central nervous system. Melanocortin, corticotropin, and histaminergic systems have an important role in the central control of food intake in birds. On the other hand, leptin decreases food intake in birds. Therefore, the aim of this study was to explain the synergistic effects of melanocortin, corticotropin, and histaminergic systems with leptin on food intake in neonatal broiler chickens.

A total of one hundred and thirty-two neonatal chicks were randomly divided into three experimental groups. Each experiment had a control group and three treatment groups (n=11 in each group). In all experiments, 3-hour food-deprived birds received intracerebroventricular ‎injections of either control diluent or drug solution. Then, the birds had ad libitum access to the ‎food and fresh water, and then cumulative food intake (gr) was measured based on the ‎percentage of the body. In the first experiment, normal saline, leptin (2.5 µg), histamine (75 nmol) and leptin plus histamine were injected.‎ The other experiments were conducted as experiment 1, but in experiment 2, MTII (MC3/MC4 receptors agonist) (2.45 pmol) and in experiment 3, urocortin (CRF1/CRF2 receptors agonist) (0.1 µg) were injected instead of histamine, either alone or in combination with leptin.

The results of the present study showed that co-injection of histamine and leptin, MTII plus leptin, and urocortin plus leptin significantly reduced food intake in broiler chickens (P<0.001).

According to the results of the present study, there is probably a synergistic effect between melanocortin, corticotropin and histaminergic systems with leptin on food intake control of neonatal broiler chicks.

Various peptides are involved in food intake regulation in the bird and mammalian brain. Melanocortin and corticotropin play an important role in food intake control. On the other hand, phoenixin-14 increases food intake. This study aimed to investigate the synergistic effects of corticotropin and melanocortin with a sub-effective dose of phoenix -14 on food intake in neonatal chickens.

A total of one hundred and ninety-two neonatal chicks were randomly divided into three experimental groups. Each experiment had a control group and three treatment groups (n=12 in each group). In all experiments, 3-hours food-deprived birds received intracerebroventricular ‎injections of either control diluent or drug solution. Then the birds had ad libitum access to the ‎food and fresh water, and then cumulative food intake (gr) was measured based on the ‎percentage of the body. In the first experiment, control solution, phoenixin-14 (0.8 nmol), Astressin-B (CRF1/CRF2 receptor antagonist; 30 µg), and phoenixin-14 + Astressin-B were injected. ‎  In the second experiment, control solution, phoenixin-14, Astressin-2B (CRF2 receptor antagonist; 30 µg), and phoenixin-14 + Astressin-2B were injected. In the third experiment, control solution, phoenixin-14 (0.8 nmol), SHU9119 (MC3/MC4 receptor antagonist; 0.5 nmol), and phoenixin-14 + SHU9119 were injected. In the fourth experiment, control solution, phoenixin-14 (0.8 nmol), MCL0020 (MC4 receptor antagonist; 0.5 nmol), and phoenixin-14 + MCL0020 were injected.

The results showed that co-inject ion of phoenixin-14 + Astressin-B and phoenixin-14 + Astressin-2B significantly increased food intake(p<0.05), while co-injection of phoenixin-14 + SHU9119 and phoenixin-14 + MCL0020 had no effect(p>0.05).

According to the results of the present study, there is probably a synergistic effect between phoenixin-14 and corticotropin system on food intake control of neonatal chicks.

Appetite modulation is a set of physiological mechanisms that influence the various areas of the central nervous system. Noradrenaline, serotonin, and oxytocin have an important role in the central control of food intake in birds. On the other hand, nesfatin decreases food intake in birds. Therefore, the aim of this study was to explain the synergistic effects of noradrenalin, serotonin, and oxytocin with nesfatin on food intake in neonatal broiler chickens.

A total of one hundred and forty-four neonatal chicks were randomly divided into three experimental groups. Each experiment had a control group and three treatment groups (n=12 in each group). In all experiments, 3-hour food-deprived birds received intracerebroventricular ‎injections of either control diluent or drug solution. Then, the birds had ad libitum access to the ‎food and fresh water, and then cumulative food intake (gr) was measured based on the ‎percentage of the body. In the first experiment, normal saline, noradrenalin, nesfatin, and noradrenalin plus nesfatin were injected.‎ In the second experiment, normal saline, serotonin, nesfatin, and serotonin + nesfatin were injected. In the third experiment, normal saline, oxytocin, nesfatin, and oxytocin plus nesfatin were injected.

The results of the present study showed that co-injection of noradrenalin and nesfatin, serotonin plus nesfatin, and oxytocin plus nesfatin significantly reduced food intake in broiler chickens (P<0.05).

According to the results of the present study, there is probably a synergistic effect between noradrenalin, serotonin, and oxytocin with nesfatin on food intake control of neonatal broiler chicks.

Serotonin (5-HT) plays an underpinning role in appetite regulation and the opioid system has a role in the modulation of the ingestion behavior in birds. The current survey was aimed to evaluate the effect of opioid receptors on serotonin-induced hypophagia in neonatal broilers. During experiments, food-deprived chickens received intracerebroventricular (ICV) injection and thereafter, the cumulative food intake was measured after 30, 60, and 120 minutes. In experiment 1, to determine the effective dose of serotonin, the control solution and the various doses of serotonin (2.5, 5, and 10 μg) were administered to birds. In the second experiment, groups received not only the control solution, but also an effective dose of serotonin (10 µg), µ-opioid receptor antagonist (β_FNA, 5 µg), and a co-injection of β_FNA (5 µg) and serotonin (10 µg), respectively. The next experiments were similar to the second experiment, however, in place of β_FNA, the antagonist of κ- opioid receptor (nor_BNI, 5 µg), the δ- opioid receptor antagonist (NTI, 5 µg), and the agonist of µ opioid receptor (DAMGO, 62.25 pmol) were used in experiments 3, 4, and 5, respectively. The results showed a dose-dependent hypophagic impact of serotonin. This effect was attenuated by β_FNA; however, nor_BNI and NTI had no effect. Furthermore, the diminishing effect of serotonin on food consumption in chickens was strengthened following DAMGO administration (p < 0.05). According to the results, the hypophagic effect of serotonin is possibly mediated through µ opioid receptors in neonatal broilers.

Food intake is regulated by a complex system of central and peripheral signals which ‎interact ‎together to modulate appetite. Noradrenaline has an essential role in the central ‎control of food ‎intake in birds. On the other hand, dopamine (DA) is a hypophagic ‎agent in birds. ‎The present ‎study aimed to investigate the effect of L-DOPA and 6-‎hydroxy-dopamine on noradrenaline-induced food intake in neonatal chickens. A total ‎of ninety-six neonatal female laying hens (Hy‎line) were randomly divided into two ‎experimental groups. Immediately after ‎intracerebroventricular (ICV) injection of ‎control diluent (normal saline) or drug solution, ‎cumulative food intake (g) was ‎measured based on the ‎percentage of the body weight (%BW). ‎Control solution (normal ‎saline, group1), L-DOPA (125 nmol, group 2), noradrenaline (300 nmol, ‎group 3), and ‎L-DOPA + noradrenaline (group 4) were injected in the first experiment.‎ In the ‎second ‎experiment, the control solution (group1), 6-hydroxy-dopamine (6-OH-DA, 2.5 nmol, ‎‎group 2), noradrenaline (300 nmol, group 3), and 6-OH-DA + noradrenaline (group 4) ‎were ‎injected. The results showed that ICV injection of noradrenaline decreased food ‎intake (P<0.05). ‎Furthermore, co-injection of L-DOPA and noradrenaline significantly ‎amplified noradrenaline-induced hypophagia in neonatal chicks (P<0.05). In contrast, ‎co-injection of 6-OH-DA and ‎noradrenaline significantly reduced hypophagia induced ‎by noradrenaline in chicks (P<0.05). ‎According to the results, noradrenaline-induced ‎food intake is probably mediated by the ‎dopaminergic system in neonatal chickens.‎

During the modification of several races, which has been done on chickens, there have been several changes in the function of neural pathways and receptor density involved in the control of food intake and appetite. Melanocortin system and its receptors are involved in the central regulation of nutritional behaviour and energy balance. Therefore, this study was designed to investigate the role of this system in the central control of food and water intake in birds.

The present study aimed to evaluate the role of MCR3 and MCR4 receptors in controlling the food and water intake in birds.

This work was performed on 48 Ross 308 broiler chicks through two experiments (each experiment in four groups). Primarily, stereotaxic surgical guide cannula was implanted in the chickens. Subsequently, in the first experiment, the chickens were divided into the four following groups: the control solution, 0.2, 2, and 10 nmol/5µl of SHU9119 (Non-selective antagonist of MCR3 and MCR4 receptors) In the second experiment, the chickens were also divided in four groups: the received control solution, 0.2, 2, and 10 nmol/5µl of MCL0020 (Selective MCR4 receptor antagonist) via intracerebroventricular (ICV) injection. Afterwards, cumulative food and water intake were measured at 30, 60, 90, 120, 150, and 180 minutes after the injection.

The results of this study showed that ICV injection of SHU9119 and MCL0020 increased cumulative food intake (P>0.05), but did not affect cumulative water intake (P<0.05).

According to the findings herein, central melanocortin system is one of the systems involved in central control of food intake in birds.

The regulation of appetite and food intake in birds are implemented as complex homeostatic mechanisms at different levels of control.

The current research aimed to investigate the effects of glycine and strychnine-sensitive receptors on food intake induced with dopamine in neonatal broiler-type chickens.

This study was conducted in five experiments (each consisting of four treatment groups with 12 birds). In experiment 1, chickens in the control group received intracerebroventricular (ICV) injection of saline (with 0.1 % Evans Blue) and different doses of dopamine (10, 20, and 40 nmol) in treatments groups 2-4, respectively. Experiments 2 and 3 were designed similar to the experiment 1 except for the fact that chickens received different doses of glycine (50, 100, and 200 nmol) and strychnine (50, 100, and 200 nmol) instead of dopamine. Experiment 4 was performed to investigate the mediatory role of strychnine (100 nmol) on food intake induced with dopamine (40 nmol). Moreover, experiment 5 investigated the interaction between non-effective doses of glycine (50 nmol) and dopamine (10 nmol) and their interplay on food intake. Afterwards, cumulative food intake based on bodyweight percentage (BW %) was measured at 30, 60, and 120 minutes after the injection.

The obtained findings revealed that effective doses of dopamine and glycine dose-dependently induced hypophagia in neonatal meat-type chickens (p < /em>≤0.05). In addition, injection of strychnine increased food intake and also inhibited the hypophagic effect induced by dopamine (p < /em>≤0.05). Furthermore, co-administration of non-effective doses of glycine and dopamine significantly decreased food intake compared to the groups which only received dopamine or glycine (p < /em>≤0.05).

Our findings suggested that strychnine-sensitive receptors may have a mediatory role in food intake induced by dopamine. Additionally, it seems that glycine and dopamine probably have synergistic effects on food intake control in neonatal meat-type chickens.

Various neurochemical pathways participate in regulating food intake in mammals and birds. The nociceptin/orphanin FQ ‎(N/OFQ) ‎is involved in the central nervous system and increass food intake. Nitric oxide (NO) is a hypophagic agent in birds. ‎The present study aimed to investigate the central nociceptin/orphanin FQ (N/OFQ) effects and its interaction with nitrergic systems on feeding behavior in neonatal chickens.

Seventy-two neonatal male broiler-type (Ross 308) chickens were divided randomly into two experimental groups. Each experiment had a control group and three treatment groups (n = 12). In all experiments, 3-hour food-deprived (FD3) birds received intracerebroventricular (ICV) ‎injections either diluent (control) or drug solution. Then the birds had ad libitum access to the ‎food and fresh water, and then cumulative food intake (g) was measured based on the ‎percentage of the body. In the first experiment, chickens received ICV injection of L-arginine (NO precursor, 400 nmol), N/‎OFQ (16 nmol), and L-arginine with N/OFQ. L-NAME (NO ‎synthase inhibitor, 200 nmol), N/OFQ (16 nmol), and L-NAME + N/‎OFQ were injected in the second experiment.‎

ICV injection of N/OFQ significantly increased food intake (p < 0.05). Injection of the N/OFQ + L-arginine significantly attenuated the hyperphagic effect induced by N/OFQ in neonatal broilers (p < 0.05). Conversely, injection of the N/OFQ + L-NAME significantly decreased the hyperphagic effect induced by N/OFQ (p < 0.05).

Our findings suggest that the hyperphagic effect of central N/OFQ ‎ in FD3 neonatal layer-type ‎chicken is probably mediated by nitric oxide.‎

Various neurochemical pathways are participating in the regulation of food intake in mammals and birds. Both oxytocin (OT) and nitric oxide (NO) are known as hypophagic agents in birds. This study consisted of 6 experiments and each experiment had 4 groups (ngroup=11, 5-day-old chickens). In all experiments, 3-hour food-deprived (FD3) birds received intracerebroventricular (ICV) injections either control diluent or drug solution. Then the birds had ad libitum access to the food and fresh water and then cumulative food intake (gr) was measured based on the percentage of the body weight (%BW). In experiments 1 to 3, ICV injections of L-arginine (precursor of NO, 200, 400, and 800 nmol), L-NAME (NOS inhibitor, 100, 200, and 400 nmol) and OT (2.5, 5, and 10 µg) were performed respectively. In experiment 4, each group received any ICV injections of L-NAME (100 nmol), OT (10 µg) or a co-injection of L-NAME (100 nmol) and OT (10 µg). In experiment 5, L-arginine (ICV, 200 nmol), OT (10 µg), or L-arginine (200 nmol) and OT (10 µg) were injected to the groups. Experiment 6 was similar to the experiment 5, although the dose of OT was 2.5 µg in all the treatment groups. Results showed that the ICV injection of L-NAME (100 nmol) significantly attenuated hypophagic effect induced by OT (10 µg) (p < 0.05). Findings suggested that NO might mediate the hypophagic effect of OT in FD3 neonatal layer-type chickens.