Progress 07/30/12 to 12/31/14
Outputs
Progress Report Objectives (from AD-416): The long-term objectives of this project are to develop an improved understanding of the genes involved in controlling feed intake and the efficiency of nutrient utilization and to determine how specific dietary nutrients affect the expression of genes (mRNAs) and gene products (peptides and proteins including those with important post-translational modifications) involved in regulating these processes in poultry. Over the next 5 years we will focus on the following two objectives: Objective 1: Identify and determine the role of specific genes and gene products that influence feeding behavior and nutrient metabolism in young growing broilers, turkey poults, and broiler breeders. Sub-objective 1.A. Determine the effects of the transition of newly hatched chicks and turkey poults from a high-fat nutrient source (yolk) to a high-carbohydrate diet on gene expression patterns in key tissues. Sub-objective 1.B. Determine the effects of feed withdrawal and refeeding on patterns of gene expression and gene product levels in young growing broiler chickens and turkey poults and in the replacement phase of broiler breeder production. Sub-objective 1.C. Determine the effects of genetic selection of chickens for high (HWS) and low (LWS) body weight phenotypes on the expression of genes and gene products that regulate feed intake and metabolic pathway activity. Objective 2: Determine the effects of varying levels of specific dietary nutrients (e.g., protein/amino acids and carbohydrate) and metabolic hormones on the expression of key genes and physiological mechanisms that regulate feed intake and nutrient utilization in young growing broilers and turkey poults. Sub-objective 2.A. Determine the effects of different levels of dietary protein, amino acids and carbohydrate on patterns of gene expression and gene product levels during phase feeding of broiler chickens. Sub-objective 2.B. Determine the effects of administration of specific nutrients and metabolic agents/hormones on physiological mechanisms involved in the regulation of feed intake and nutrient utilization in young growing broilers and turkey poults. Objective 3: Identify and analyze gene and gene product interactions that promote protein utilization efficiency and growth in broilers by characterizing the physiological mechanisms underlying stabilization of the chicken gut against pathogens; and improved understanding of nutrient uptake and processing in the cells of the gastrointestinal tract. Objective 4: Assess, develop, and apply microbiome and metagenomic based model strategies in poultry to define the role of the microflora in the regulation of nutrient uptake and utilization in the gastrointestinal tract during post-hatch development of broilers. Objective 5: Develop novel alternative strategies to the use of antimicrobial growth promoters in broilers to abrogate consequences of host reactivity to pathogens and to improve health, nutrient utilization efficiency and growth rate. Approach (from AD-416): This project addresses the need to understand regulatory mechanisms of feed intake and nutrient utilization in poultry species through identification and study of individual genes and gene products involved in these complex and economically important production traits. The first objective will investigate genes controlling feed intake and nutrient utilization and to determine how their expression is affected during the critical adaptation to feeding initiation occurring during early post- hatch development of broiler chickens and turkeys. The consequences of feed restriction and refeeding on expression of genes and gene products involved in key control points for feed intake and metabolic activity at different ages and stages of poultry production will be determined. Two genetic lines of chickens, selected for high and low body weight, will be studied to compare and contrast changes in gene and gene product expression and plasma metabolite and metabolic hormone patterns characteristic of these two phenotypes and to determine how such changes may relate to the marked differences in feed intake and metabolism exhibited by both lines. A second objective will determine the effects of feeding broilers varying levels of crude protein, individual amino acids or carbohydrate on the expression of genes and gene products that play important roles in growth and energy balance and to correlate gene expression and endocrine profiles with changes in whole body parameters such a fat accretion, meat yield and skeletal growth in broilers during the different phases of the production cycle. Broiler chickens and turkey poults from hatch to 4 weeks of age will be administered substances known to affect nutrient levels, endocrine profiles, metabolic activity and feed intake to determine relationships between these parameters and peripheral tissue and central nervous system regulatory mechanisms. Expression of candidate genes will be assayed in chicken and turkey tissue samples using reverse transcription polymerase chain reaction assays. Total RNA from broiler liver, hypothalamus, breast muscle and duodenum tissues sampled at hatch (day 0) and on day 7 post- hatch will be subjected to in-depth replicated microarray screening to determine changes in gene expression related to the initiation of feeding. Plasma samples will be analyzed for metabolite/nutrient levels and a series of metabolic hormones. Tissues will be analyzed for enzyme activities, in vitro lipogenic activity, nutrient-sensing transcription factors, and activity of specific kinase pathways. Information on metabolic and endocrine profiles will then be correlated with changes in gene expression with particular emphasis on those genes whose expression is responsive to nutrient and/or hormonal signaling. This functional genomics approach will yield new information about genes encoding important regulatory factors such as hormones, neuropeptides, receptors, transporters, enzymes and transcription factors that together form a complex and interrelated series of neural, endocrine and metabolic pathway networks working in concert to control feed intake and nutrient utilization in poultry. A new project plan was written and reviewed by OSQR in FY14, and was approved November 2014 (FY15). January 1, 2015, marked the start date for the Project Plan 8042-31000-106-00D approved by OSQR. Project Plan 8042-31000-100-00D has been terminated and the active progress report is documented in the Annual Report under Project Plan 8042-31000-106-00D.
Impacts
(N/A)
Publications
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Progress 10/01/13 to 09/30/14
Outputs
Progress Report Objectives (from AD-416): The long-term objectives of this project are to develop an improved understanding of the genes involved in controlling feed intake and the efficiency of nutrient utilization and to determine how specific dietary nutrients affect the expression of genes (mRNAs) and gene products (peptides and proteins including those with important post-translational modifications) involved in regulating these processes in poultry. Over the next 5 years we will focus on the following two objectives: Objective 1: Identify and determine the role of specific genes and gene products that influence feeding behavior and nutrient metabolism in young growing broilers, turkey poults, and broiler breeders. Sub-objective 1.A. Determine the effects of the transition of newly hatched chicks and turkey poults from a high-fat nutrient source (yolk) to a high-carbohydrate diet on gene expression patterns in key tissues. Sub-objective 1.B. Determine the effects of feed withdrawal and refeeding on patterns of gene expression and gene product levels in young growing broiler chickens and turkey poults and in the replacement phase of broiler breeder production. Sub-objective 1.C. Determine the effects of genetic selection of chickens for high (HWS) and low (LWS) body weight phenotypes on the expression of genes and gene products that regulate feed intake and metabolic pathway activity. Objective 2: Determine the effects of varying levels of specific dietary nutrients (e.g., protein/amino acids and carbohydrate) and metabolic hormones on the expression of key genes and physiological mechanisms that regulate feed intake and nutrient utilization in young growing broilers and turkey poults. Sub-objective 2.A. Determine the effects of different levels of dietary protein, amino acids and carbohydrate on patterns of gene expression and gene product levels during phase feeding of broiler chickens. Sub-objective 2.B. Determine the effects of administration of specific nutrients and metabolic agents/hormones on physiological mechanisms involved in the regulation of feed intake and nutrient utilization in young growing broilers and turkey poults. Objective 3: Identify and analyze gene and gene product interactions that promote protein utilization efficiency and growth in broilers by characterizing the physiological mechanisms underlying stabilization of the chicken gut against pathogens; and improved understanding of nutrient uptake and processing in the cells of the gastrointestinal tract. Objective 4: Assess, develop, and apply microbiome and metagenomic based model strategies in poultry to define the role of the microflora in the regulation of nutrient uptake and utilization in the gastrointestinal tract during post-hatch development of broilers. Objective 5: Develop novel alternative strategies to the use of antimicrobial growth promoters in broilers to abrogate consequences of host reactivity to pathogens and to improve health, nutrient utilization efficiency and growth rate. Approach (from AD-416): This project addresses the need to understand regulatory mechanisms of feed intake and nutrient utilization in poultry species through identification and study of individual genes and gene products involved in these complex and economically important production traits. The first objective will investigate genes controlling feed intake and nutrient utilization and to determine how their expression is affected during the critical adaptation to feeding initiation occurring during early post- hatch development of broiler chickens and turkeys. The consequences of feed restriction and refeeding on expression of genes and gene products involved in key control points for feed intake and metabolic activity at different ages and stages of poultry production will be determined. Two genetic lines of chickens, selected for high and low body weight, will be studied to compare and contrast changes in gene and gene product expression and plasma metabolite and metabolic hormone patterns characteristic of these two phenotypes and to determine how such changes may relate to the marked differences in feed intake and metabolism exhibited by both lines. A second objective will determine the effects of feeding broilers varying levels of crude protein, individual amino acids or carbohydrate on the expression of genes and gene products that play important roles in growth and energy balance and to correlate gene expression and endocrine profiles with changes in whole body parameters such a fat accretion, meat yield and skeletal growth in broilers during the different phases of the production cycle. Broiler chickens and turkey poults from hatch to 4 weeks of age will be administered substances known to affect nutrient levels, endocrine profiles, metabolic activity and feed intake to determine relationships between these parameters and peripheral tissue and central nervous system regulatory mechanisms. Expression of candidate genes will be assayed in chicken and turkey tissue samples using reverse transcription polymerase chain reaction assays. Total RNA from broiler liver, hypothalamus, breast muscle and duodenum tissues sampled at hatch (day 0) and on day 7 post- hatch will be subjected to in-depth replicated microarray screening to determine changes in gene expression related to the initiation of feeding. Plasma samples will be analyzed for metabolite/nutrient levels and a series of metabolic hormones. Tissues will be analyzed for enzyme activities, in vitro lipogenic activity, nutrient-sensing transcription factors, and activity of specific kinase pathways. Information on metabolic and endocrine profiles will then be correlated with changes in gene expression with particular emphasis on those genes whose expression is responsive to nutrient and/or hormonal signaling. This functional genomics approach will yield new information about genes encoding important regulatory factors such as hormones, neuropeptides, receptors, transporters, enzymes and transcription factors that together form a complex and interrelated series of neural, endocrine and metabolic pathway networks working in concert to control feed intake and nutrient utilization in poultry. During FY2014 progress was made towards Objective 1. The timing for the gene expression of factors involved in the breakdown of proteins into amino acids and their transport from the intestine to the blood stream and vice versa was examined during the period of one day post-hatch until 21 days post-hatch in the three regions of the small intestine (duodenum, jejunum, ileum) and the ceca, which consists of blind pouches at the intersection of the small and large intestine. The expression level of each gene was found to be very stable in the duodenum, jejunum and ileum with little to no difference in the abundance of each gene between each intestinal region. Additionally, there were no significant differences in expression within each region at different days after hatch. This indicated that the factors necessary for protein breakdown or transport are present at similar levels throughout all regions of the small intestine as early as one day post hatch. On the other hand, the ceca had limited expression of the factors. The expression of PepT1 (oligopeptide tranporter) and B0+AT (neutral amino acid transporter) was not detected in the ceca, and the levels of expression for the remaining genes was generally lower than that observed in the small intestine. The primary function of the ceca in the chicken is not well understood, but the current results indicate that this organ may function in a limited capacity for the second digestion of protein and the uptake of amino acids. A study was carried out towards Objective 1 to determine whether parasitic infection of the gut caused by the protozoan parasite Eimeria (E.) maxima elicited a change in the capacity of the gut to process and absorb amino acids. This parasite invades the epithelial cells lining the intestine, primarily, in the jejunum and causes a decrease in weight gain due to anorexia and diarrhea. It is therefore logical to propose that nutrient uptake in parasitized birds is compromised. The expression of factors involved in the breakdown of proteins into amino acids and their transport was determined in jejenum of E. maxima infected birds at day of infection and days 14 post infection. At early as well as late time points, expression was similar to that seen in uninfected birds. At days 5 and 7, when the pathology is greatest, a decrease in the expression of factors located on the brush border side (apical) of the gut epithelium facing the gut lumen was noted, while an increase in the expression of factors that reside on the basolateral surface of the gut epithelium was observed. Also, a very large decrease in expression of an innate anti-microbial peptide was noted at day 7 post-infection. If the protein shows a similar pattern of expression, it is possible that by limiting the amino acids that enter the epithelial cell via apical transporters and increasing the flow of amino acids out of the cell via the basolateral transporters that shuttle the amino acids from the epithelial cell to the blood vessel, the host is attempting to limit the parasite infection or starve the parasite by limiting the amount of nutrients available. Additionally, by decreasing the expression of antimicrobial peptides the parasite makes the host susceptible to secondary bacterial infections. Significant Activities that Support Special Target Populations: Mentored a Hispanic student who is a part of the Hispanic Serving Institutions program for eight weeks during the summer. Accomplishments 01 Determined that chicks are able to digest proteins at hatch. Shortly after hatch, chicks are fed a diet that is high in protein content (~23- 24%); ARS scientists have determined that the components of the mechanisms that break down and absorb protein denied amino acids in the gut are present before as well as after hatch. Because protein is the costliest ingredient in the poultry diet it is important to ascertain that it is used effectively. It was also determined for the first time that a portion of the large intestine called the ceca, the function of which is not well understood, suggests that the ceca may also have a role in the absorption of amino acids because it contains components required to absorb amino acids following protein digestion. This information can be utilized by poultry producers to continue to feed high protein content diet which will be efficiently utilized by growing chicks.
Impacts
(N/A)
Publications
- Su, S., Miska, K.B., Fetterer, R.H., Jenkins, M.C., Wong, E. 2014. Expression of digestive enzymes and nutrient transporters in Eimeria acervulina-challenged layers and broilers. Poultry Science. 95:1217-1226.
- Fetterer, R.H., Miska, K.B., Mitchell, A.D., Jenkins, M.C. 2013. The use of dual-energy X-ray absorptiometry (DEXA) to assess the impact of Eimeria infections in broiler chicks. Avian Diseases. 57(2):199-204.
- Jenkins, M.C., Parker, C.C., Obrien, C.N., Persyn, J., Barlow, D., Miska, K.B., Fetterer, R.H. 2013. Increased efficacy of Eimeria oocysts delivery by gel beads or spray vaccination. Avian Diseases. 57(3):622-626.
- Jenkins, M.C., Parker, C.C., Obrien, C.N., Miska, K.B., Fetterer, R.H. 2013. Different susceptibilities of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts to dessication. Journal of Parasitology. 99(5) :899-902.
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Progress 10/01/12 to 09/30/13
Outputs
Progress Report Objectives (from AD-416): The long-term objectives of this project are to develop an improved understanding of the genes involved in controlling feed intake and the efficiency of nutrient utilization and to determine how specific dietary nutrients affect the expression of genes (mRNAs) and gene products (peptides and proteins including those with important post-translational modifications) involved in regulating these processes in poultry. Over the next 5 years we will focus on the following two objectives: Objective 1: Identify and determine the role of specific genes and gene products that influence feeding behavior and nutrient metabolism in young growing broilers, turkey poults, and broiler breeders. Sub-objective 1.A. Determine the effects of the transition of newly hatched chicks and turkey poults from a high-fat nutrient source (yolk) to a high-carbohydrate diet on gene expression patterns in key tissues. Sub-objective 1.B. Determine the effects of feed withdrawal and refeeding on patterns of gene expression and gene product levels in young growing broiler chickens and turkey poults and in the replacement phase of broiler breeder production. Sub-objective 1.C. Determine the effects of genetic selection of chickens for high (HWS) and low (LWS) body weight phenotypes on the expression of genes and gene products that regulate feed intake and metabolic pathway activity. Objective 2: Determine the effects of varying levels of specific dietary nutrients (e.g., protein/amino acids and carbohydrate) and metabolic hormones on the expression of key genes and physiological mechanisms that regulate feed intake and nutrient utilization in young growing broilers and turkey poults. Sub-objective 2.A. Determine the effects of different levels of dietary protein, amino acids and carbohydrate on patterns of gene expression and gene product levels during phase feeding of broiler chickens. Sub-objective 2.B. Determine the effects of administration of specific nutrients and metabolic agents/hormones on physiological mechanisms involved in the regulation of feed intake and nutrient utilization in young growing broilers and turkey poults. Approach (from AD-416): This project addresses the need to understand regulatory mechanisms of feed intake and nutrient utilization in poultry species through identification and study of individual genes and gene products involved in these complex and economically important production traits. The first objective will investigate genes controlling feed intake and nutrient utilization and to determine how their expression is affected during the critical adaptation to feeding initiation occurring during early post- hatch development of broiler chickens and turkeys. The consequences of feed restriction and refeeding on expression of genes and gene products involved in key control points for feed intake and metabolic activity at different ages and stages of poultry production will be determined. Two genetic lines of chickens, selected for high and low body weight, will be studied to compare and contrast changes in gene and gene product expression and plasma metabolite and metabolic hormone patterns characteristic of these two phenotypes and to determine how such changes may relate to the marked differences in feed intake and metabolism exhibited by both lines. A second objective will determine the effects of feeding broilers varying levels of crude protein, individual amino acids or carbohydrate on the expression of genes and gene products that play important roles in growth and energy balance and to correlate gene expression and endocrine profiles with changes in whole body parameters such a fat accretion, meat yield and skeletal growth in broilers during the different phases of the production cycle. Broiler chickens and turkey poults from hatch to 4 weeks of age will be administered substances known to affect nutrient levels, endocrine profiles, metabolic activity and feed intake to determine relationships between these parameters and peripheral tissue and central nervous system regulatory mechanisms. Expression of candidate genes will be assayed in chicken and turkey tissue samples using reverse transcription polymerase chain reaction assays. Total RNA from broiler liver, hypothalamus, breast muscle and duodenum tissues sampled at hatch (day 0) and on day 7 post- hatch will be subjected to in-depth replicated microarray screening to determine changes in gene expression related to the initiation of feeding. Plasma samples will be analyzed for metabolite/nutrient levels and a series of metabolic hormones. Tissues will be analyzed for enzyme activities, in vitro lipogenic activity, nutrient-sensing transcription factors, and activity of specific kinase pathways. Information on metabolic and endocrine profiles will then be correlated with changes in gene expression with particular emphasis on those genes whose expression is responsive to nutrient and/or hormonal signaling. This functional genomics approach will yield new information about genes encoding important regulatory factors such as hormones, neuropeptides, receptors, transporters, enzymes and transcription factors that together form a complex and interrelated series of neural, endocrine and metabolic pathway networks working in concert to control feed intake and nutrient utilization in poultry. During FY2013, progress was made towards both objectives. For Objective 1, the timing for the gene expression of factors involved in the breakdown of proteins into amino acids and the subsequent transport of amino acids from the intestine to the blood stream and vice versa was examined during chicken embryo development. Prior to day 15, only amino acid transporters that move amino acids between intestinal cells and the embryonic blood supply were expressed. This suggests that during early embryo development, the primary movement of amino acids is from the blood to intestine for the growth of the intestinal tract. By day 15, genes for amino acid transporters that take up nutrients from dietary components were detected. This suggests that the embryonic gut is ready to process and absorb amino acids approximately 6 days before hatch. While different regions of the gut have distinct nutrient uptake efficiencies, the expression of amino acid transporters did not differ between the unique functional regions of the embryonic gut. This included a region at the beginning of the large intestine called the cecum, which is not thought to play a role in amino acid absorption; results from this study are the first to suggest otherwise. Throughout embryonic development, high levels of amino acid transporter expression were seen in the liver, which in the embryo carries out most metabolic functions. Additional experiments are ongoing to determine the expression of the amino acid transporters in the gut of chickens collected at hatch and subsequent to feeding through post-hatch day 21. During this time the chicks adjust from the yolk�s high fat diet to a corn/soybean meal diet high in protein and carbohydrates. Progress has also been made toward Objective 2 to determine how the bacteria in the gut is established under normal rearing conditions. Contents of the gut as well as scrapings of the gut lining have been collected from newly hatched broiler chicks up to 21 day old birds. Microbial DNA has been extracted and qualitative/quantitative analysis of the bacterial populations and the population profile variability with age will be examined.
Impacts
(N/A)
Publications
- Miska, K.B., Kim, S., Fetterer, R.H., Dalloul, R., Jenkins, M.C. 2013. Macrophage Migration Inhibitory Factor (MIF) of the protozoan parasite Eimeria influences the components of the immune system of its host, the chicken. Parasitology Research. 112:1935-1944.
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