Project description:Delayed access to feed following hatching has been associated with reduction in growth performance in chicks. However, the gene networks within the hypothalamus that regulate feed intake and metabolism, and the effects of fasting on those pathways are not well understood. The present experiment evaluated global hypothalamic gene expression in neonatal chicks using the Arizona Gallus gallus 20.7K Oligo Array v1.0 to elucidate genes and pathways regulated by feeding, fasting, and refeeding. Ten groups of chicks were sampled over four days post-hatch, including: control (at hatch), 24h fed, 24h fasted, 48h fed, 48h fasted, 48h fasted then 4h refed, 72h fed, 48h fasted then 24h refed, 96h fed, and 48h fasted then 48h refed. Non-esterified fatty acids were elevated, and triglycerides were decreased in fasted chicks at 24 and 48h, indicating that fasting induced physiological changes. Hypothalamic samples were collected from 16 chicks per group, and total RNA was extracted and pooled for hybridization (n=4). Expression patterns of selected genes were confirmed by quantitative real-time PCR. Two-fold differences in gene expression were detected in 1,272 genes between treatment groups, and of those, 119 genes were significantly (P<0.05) different. Assignment of gene ontology terms to the significant genes resulted in 34 different categories of biological processes, with 24% of genes participating in signal transduction, transport, or metabolic processes. Genes that were upregulated during fasting (and confirmed by qPCR) include FK506BP51, which is involved in the formation of steroid receptor complexes, and deiodinase type II, which is responsible for converting the thyroid hormone T4 into T3. Confirmed genes, downregulated due to fasting, included proopiomelanocortin and fatty acid binding protein 7. Other regulated genes were identified that play a role in feeding and obesity in other species, such as relaxin 3 and adrenergic receptor-β2. Further analysis of differentially regulated genes could provide new information regarding the role of the hypothalamus in feed intake and metabolism. Keywords: Metabolic perturbation
Project description:Delayed access to feed following hatching has been associated with reduction in growth performance in chicks. However, the gene networks within the hypothalamus that regulate feed intake and metabolism, and the effects of fasting on those pathways are not well understood. The present experiment evaluated global hypothalamic gene expression in neonatal chicks using the Arizona Gallus gallus 20.7K Oligo Array v1.0 to elucidate genes and pathways regulated by feeding, fasting, and refeeding. Ten groups of chicks were sampled over four days post-hatch, including: control (at hatch), 24h fed, 24h fasted, 48h fed, 48h fasted, 48h fasted then 4h refed, 72h fed, 48h fasted then 24h refed, 96h fed, and 48h fasted then 48h refed. Non-esterified fatty acids were elevated, and triglycerides were decreased in fasted chicks at 24 and 48h, indicating that fasting induced physiological changes. Hypothalamic samples were collected from 16 chicks per group, and total RNA was extracted and pooled for hybridization (n=4). Expression patterns of selected genes were confirmed by quantitative real-time PCR. Two-fold differences in gene expression were detected in 1,272 genes between treatment groups, and of those, 119 genes were significantly (P<0.05) different. Assignment of gene ontology terms to the significant genes resulted in 34 different categories of biological processes, with 24% of genes participating in signal transduction, transport, or metabolic processes. Genes that were upregulated during fasting (and confirmed by qPCR) include FK506BP51, which is involved in the formation of steroid receptor complexes, and deiodinase type II, which is responsible for converting the thyroid hormone T4 into T3. Confirmed genes, downregulated due to fasting, included proopiomelanocortin and fatty acid binding protein 7. Other regulated genes were identified that play a role in feeding and obesity in other species, such as relaxin 3 and adrenergic receptor-β2. Further analysis of differentially regulated genes could provide new information regarding the role of the hypothalamus in feed intake and metabolism. Keywords: Metabolic perturbation Ten experimental groups with 4 replicates each were analyzed. A reference RNA design was used for this microarray. Equal amounts of amplified RNA (aRNA) from all samples were pooled and labeled with the Alexa 647 to create the reference pool. Each individual sample was labeled with Alexa 555. Each slide was hybridized with both the reference pool and one sample.
Project description:A reduction in voluntary feed intake is observed in ruminants consuming nutrient deficient diets, such as those with a low CP or P content, and has been attributed to active metabolic regulation, rather than a physical constraint. The hypothalamus is the key integrator of feed intake regulation in mammals. The objectives of this experiment were to 1) establish a model of metabolic feed intake regulation in ruminants consuming diets of variable CP and P content, and 2) determine key biochemical pathways and influential points of regulation within the hypothalamus. Merino wethers [n = 40; 23.7 ± 1.4 kg liveweight (mean ± SD)] were fed one of five dietary treatments (n = 8/treatment) for 63 days in individual pens. The treatments included targeted combinations of high (H) and low (L) CP (110 and 55 g/kg DM) and high and low P (2.5 and 0.7 g/kg DM) with 9 MJ metabolisable energy (ME) per kg DM which were fed ad libitum (UMEI; unrestricted ME intake) resulting in four experimental diets (HCP-HP-UMEI, LCP-HP-UMEI, HCP-LP-UMEI and LCP-LP-UMEI). An additional nutritional treatment (HCP-HP-RMEI) restricted intake of the HCP-HP diet to an equivalent ME intake of wethers consuming the LCP-LP-UMEI treatment. Wethers offered the LCP-HP-UMEI, HCP-LP-UMEI and LCP-LP-UMEI treatments consumed 42, 32 and 49% less total DM (P ≤ 0.05), respectively than the HCP-HP-UMEI treatment, and this was not attributable to any physical limitation of the rumen. Plasma concentrations of urea nitrogen and inorganic phosphate indicated that these nutrient deficiencies were successfully established. To assess potential mechanisms, RNA-seq was conducted on samples from the arcuate nucleus (ARC), ventromedial hypothalamus and lateral hypothalamus of the wethers, yielding a total of 301, 8 and 148 differentially expressed genes across all pairwise comparisons, respectively. The expression of NPY, AGRP and CARTPT, known for their regulatory role in mammalian feed intake regulation, had a similar transcriptional response in the ARC of wethers consuming nutrient deficient treatments and those consuming a ME restricted treatment, despite these wethers expressing behaviours indicative of satiated and hungry states, respectively. In addition, genes involved with glycolysis (TPI1), the citric acid cycle (CS, OGDH, GLUD1, GOT1) and oxidative phosphorylation (COX5A, ATP5MC1, ATP5F1B, ATP5MC3) were downregulated in the ARC of wethers fed a nutrient deficient (LCP-LP-UMEI) relative to the non-deficient (HCP-HP-UMEI) treatment. In summary, a model for voluntary feed intake restriction was established to determine genome-wide molecular changes in the hypothalamus of young ruminants.
Project description:Aflatoxin is a toxic secondary metabolite produced by the fungi Aspergillus flavus and A. parasiticus. Ingredients of livestock and poultry feed are often contaminated with aflatoxin. Aflatoxin affects many species including humans, dogs, cats, pigs, cattle, and poultry, with liver being the major organ affected. A chicken model was used to evaluate the effect of aflatoxin on hepatic gene expression. Seventy five day-old male broiler chicks were assigned to three dietary treatments (5 replicates of 5 chicks each) from hatch to day 21. The diets contained 0, 1 and 2 mg/kg aflatoxin/kg of feed. Feed intake, body weight gain, liver weights and serum chemistry were evaluated at the end of the study and liver samples were collected in RNase free tubes and stored at -80 ºC. Aflatoxin reduced (P ≤ 0.05) feed intake, body weight, serum total proteins, serum calcium and phosphorus but increased (P < 0.01) liver weights in a dose dependent manner. Microarray experiments were conducted using chicken long oligo arrays, to identify the changes in hepatic gene expression in chicks fed 0 (control) and 2mg/kg aflatoxin/kg of feed. A loop design was followed for microarray experiments with three technical and four biological replicates per treatment group. RNA was extracted from liver tissue and its quality was determined using gel electrophoresis. High quality RNA was purified from DNA contamination, reverse transcribed to cDNA and was used for microarray hybridizations. Microarray data was analyzed using a 2-step ANOVA model using GenePix and MAANOVA softwares, and the differentially expressed genes were identified using SAM, TIGR, and Cluster softwares. The microarray data was validated using real time PCR. It is hypothesized that genes associated with antioxidant, detoxification and immune systems were downregulated and the genes involved in cell proliferation were up-regulated in birds fed aflatoxin compared to controls Keywords: aflatoxin, chicken liver, microarrays, gene expression
Project description:To better understand the hepatic metabolic response to intermittent fasting in chickens, Red Junglefowl chickens were raised on ad libitum (AL) feed until 14 days of age and then kept on AL feeding, switched to chronic feed restriction (CR) to around 70% or switched to an intermittent fasting (IF) regimen consisting of two fed days (150% of age-matched weight-specific AL intake offered daily) followed by a non-fed day. AL and CR were culled at 36 days of age, and IF birds either at 40 days of age (second consecutive feeding day) or 41 days of age (fasting day).
Project description:Hunger, driven by negative energy balance, elicits the search for and consumption of food. In mammals, this is orchestrated principally through the activity of neurons in the hypothalamus, direct manipulation of which can potently drive food intake. However, the neural circuits outside of the hypothalamus that control feeding are poorly understood. Here, we identify two functionally opponent cell types within the dorsal raphe nucleus (DRN), marked by the vesicular transporters for GABA (Vgat) or glutamate (VGLUT3), that project to many known feeding centers and rapidly control feeding. We find that DRNVgat neurons drive, while DRNVGLUT3 neurons suppress, food intake. Furthermore, through the development and application of cell type-specific molecular profiling technologies, we identify many differentially expressed transmembrane receptors, which may represent unique druggable targets. Local application of agonists for these receptors potently modulates feeding, recapitulating the effects of cell-specific manipulations. Together, these data establish a key role for the DRN in controlling food intake and add an important anatomic site that controls energy balance.
Project description:Newly-hatched domestic chick serves as an important model for studies of neural and behavioral plasticity, particularly with respect to learning and memory such as filial imprinting. Imprinting is assumed to be a unique case of recognition learning with some characteristic features, such as sensitive period and irreversibility. However, the molecules involved in the memory process are yet to be fully identified. To address this issue, we attempted to identify the genes differentially expressed at an earlier phase of filial imprinting than described in our previous report (Brain Res. Bull.76, 275-281 (2008)). One-day-old chicks were trained for imprinting for 1 h and whole brains were collected and used for cDNA microarray analysis and quantitative RT-PCR. We identified 18 genes upregulated accompanying filial imprinting. These results suggested that the increase of these 18 genes associated with filial imprinting might play an important role in the acquisition of memory in the filial imprinting. Total RNA was extracted from whole brains of trained chicks (n=16) and control dark-reared chicks (n=16). Using these total RNAs, we performed RT-PCR to distinguish male chicks from females. Then total RNAs were separated and mixed in four groups (1, male trained (n=8); 2, female trained (n=8); 3, male dark-reared (n=8); and 4, female dark-reared chicks (n=8)), and we performed cDNA microarray expression analysis to identify the upregulated genes following imprinting (1 versus 3 and 2 versus 4).
Project description:Anorexia is a common symptom among cancer patients and contributes to malnutrition and insufficient food intake. In cancer-induced anorexia, food intake regulation in the hypothalamus appears to be impaired. A negative energy balance persists and accelerates muscle wasting and malnutrition. Moreover, it strongly affects mortality and survival in these patients. Here, we show that the neuropeptide Y system (NPY) appears to fail to respond adequately to changes in energy balance during cancer cachexia. In addition, we investigate the connection between serotonin and NPY release in hypothalamic cell lines. Lewis Lung tumour cells were intramuscularly inoculated 6w old male C57BL/6 mice. Body weight and food intake were measured 3 times a week. On day 10, 14 and 17 hypothalamus was dissected and used for gene expression profiling.
Project description:The arcuate nucleus of the hypothalamus (ARH) is one key structure controlling energy homeostasis. While it has been shown that the biogenic amines dopamine and serotonin modulate food intake controlling NPY/AgRP and/or POMC neurons in the ARH, the neural substrates that mediate the effect of noradrenaline (NA) on energy homeostasis remain elusive. By electrophysiological recordings and cell type-specific transcriptomics we show that the main neuronal populations in the ARH, NPY/AgRP and POMC neurons express a combination of excitatory and inhibitory adrenergic receptors (ARs). Surprisingly, NA had a clear differential effect on these neurons. Activation of NPY/AgRP neurons is mediated by _1A - and _- ARs, while POMC neurons are inhibited via _2A ARs. Collectively, our data indicate an orexigenic influence of NA on the ARH circuitry that controls energy balance