عنوان مقاله [English]
Introduction Feed intake includes a set of physiological mechanisms that affects different parts of the central nervous system. Histamine as a central neurotransmitter involved in regulating appetite. This study is conducted to evaluate the effects of determining the importance of nutrition mode, on the effect caused by histamine via intra-peritoneal injection histamine peripheral receptors in satiety and hunger on feed and water of broilers. When the histamine injected central, feed consumption will be through of H1 histamine receptor. It seems peritoneum injection of histamine, prevents the feed consumption in broilers. We also designed some tests to determinate the effects of H1 and H2 receptors on feed consumption in growing broilers. Histamine through its H1 receptors prevents the feed absorption in broilers.
Materials and Methods In this study, environmental impacts of histaminergic system on feed intake male Ross broiler chickens were studied in 2 phases. 32 one-day-old broilers were raised to four-week-old in group and then in the 4th week as single. The temperature in the first week of nourishment was set at 32-31 °C, and the every week the temperature was lowered 3-2 degrees, so that during the tests the temperature was adjusted between 24-21 ° C. Average weight of chickens at the time of the experiment (4 weeks), was 720 gr.
Data was analyzed in form of repeated measurements and averages were compared using LSMEANS test. Data analysis was performed using SAS software. Treatments included 40 mg/kg inject able chloramphenicol, 5.2 mg/kg famotidine, 1 mg/kg histamine, and saline. The amount of water consumed was measured by drinker scaled with accuracy 1ml. Total volume injected was 5.0 ml intra peritoneal.
Results and Discussion Results showed a significant difference between feed intake of hungry broilers and broilers who had free access to feed. Histamine induced lower feed intake in both satiety and hunger, but its effect was more significant in satiety. The tests showed that water intake in satiety and hunger modes were significantly different. The amount of water usage in hungry chickens was more as feed intake in hungry chickens was also more. We can say that water intake depends on the amount of feed intake and water intake also rises with increased feed intake. Serotonin is effective in reducing the amount of feed intake and reduces the duration and frequency of feed intake, but it is not effective on latency time before eating. Histamine through leptin may decrease feed intake. It also recognized that the saturation of cholecystokinine depends on liberalization of histamine, which is bound on H1 and H2receptor and ultimately reduces feed intake. Chloramphenicol reduced feed intake in both satiety and hunger. Famotidine induced lower feed intake in first minutes, but had no effect in hunger. Water appetite was decreased by chloramphenicol but famotidine increased water appetite by inhibiting H2 receptor, both in satiety and hunger. Seems that histamine and cholinergic systems are linked together and histamine modifies cholinergictrans mission. Theoretically cholinergic system reduces blood pressure, thus it reduces water loss from the kidneys and there by leads to secretion of kidneys and affect brain and causes sense of thirst and result in increasing water intake.
Conclusion Finally, H1 and H2 receptors play role in feed and water intake. These antagonists were involved in controlling feed intake if they cause increased feed intake and may other receptors be involved reduced feed intake result from histamine. Receptor antagonistH1 (chlorpheniramine), in both satiety and hunger modes causes significant decrease in feed intake, also receptor antagonistH2 (famotidine) at limited times significantly decreased feed intake in chickens with no limitation period, that this reduction in feed intake in satiety mode was more and total, chickens in satiety mode consume less feed than hungry chicks. Chlorpheniramine causes significantly decreased water intake in both satiety and hunger. Famotidine significantly increases water intake in hunger mode and in satiety mode it significantly increases water intake in the first hours after injection. Histamine resulted in significant reduction of water intake in satiety and cause to significant increase of water intake in hunger mode. Considering the increased water intake by histamine and reducing water intake by chlorpheniramine at the same time, in hunger mode H1receptor is involved in increased water intake caused by histamine. Peritoneal injection of histamine shows that water consumption increase with feed consumption and it seems this occurrence regulated with some different mechanisms such as release of angiotens in and histamine.