Prologue
Energy is the most elusive nutrient in poultry diets. Simply reducing the energy content in poultry feed may not be a viable option for cost-saving in feed formulation.
An economical solution is to enable efficient energy utilization; another option is to reduce the energy value to partial extent while maintaining bird’s performance is the dietary supplementation of suitable additives. In this context, Indian Herbs Specialities took the initiative to evaluate energy repartitioning advantage of natural choline supplement, BioCholine.
Introduction
Amongst all nutrients, energy is one of the most expensive nutrients in poultry feed. Feed has always been the biggest production cost faced by poultry farmers and recent rises in global prices, combined with supply volatility, mean that producers are now having to look harder for ways to maintain their margins. The challenge for everyone involved in poultry production is to feed birds with a balanced diet, at the lowest cost, yet still produce animal protein that meets the customer’s requirements to maximize farm profitability and meet environmental and animal welfare standards. Feed represents the major cost of animal production, constituting up to 70 percent of the total.
Protein, fat, and starch provide energy for maintenance, growth, and production. In feed formulation, improving feed efficiency and reducing cost per kilogram of carcass meat yield are the major goals of nutritionists. Of total feed cost, about 95 percent is used to meet energy and protein requirements, about 3-4 percent for major mineral, trace mineral, and vitamin requirements, and 1-2 percent for various feed additives. Energy is the largest component of poultry diets. Simply reducing the energy content in poultry feeds may not be a viable option for cost-saving in feed formulation. Energy is one of the most limiting factors in the feed and lowering energy will result in increased feed conversion. An economical solution is to enable efficient energy utilization; another option is to reduce the energy value to partial extent while maintaining bird’s performance is the dietary supplementation of suitable additives. Those additives that can provide an energy-sparing effect. In this context, a number of studies have been conducted where supplementing phytogenic additives has shown to provide an energy repartitioning effect and therefore sparing energy of up to 60-70 kcal/kg in starter, grower, and finisher diets.
Choline: The Conditionally Essential Nutrient with Critical Metabolic Role
Choline has been known for its nutritional advantages for the last 10 decades, and the benefits of choline supplementation in monogastrics are well established. Choline is a quasi-vitamin, and its dietary supplementation improves feed efficiency besides helping to prevent fatty liver in birds. Choline is known to optimize energy metabolism, control fatty liver syndrome (FLS), and reduce body fat. It is indispensable for efficient nutrient assimilation and hepatic fat metabolism. Natural choline supplement BioCholine contains highly bioavailable choline in the conjugated form of phosphatidylcholine along with other phospholipids and PUFA.
BioCholine is natural, stable, non-hygroscopic, and non-corrosive. Since phosphatidylcholine is readily and highly bioavailable through BioCholine, it does not need intermediate steps and is a readily available source for VLDL formation, thereby regulating hepatic lipid pathways. Phosphatidylcholine acts as an agonist (promoter) of Peroxisome Proliferator Activated Receptors Alpha (PPARα), proteic nuclear receptors acting on transcription processes. PPARα is present both in the intestine and in the liver, indicating that natural choline (phosphatidylcholine) begins to act in the enterocytes and later, in the liver, optimizing the absorption of nutrients in the diets and improving feed conversion and other productive parameters.
PPAR-α: The Key Nutritional Sensor for Metabolic Adaptation
PPARα functions as a lipid sensor in the liver and recognizes and responds to the influx of fatty acids by stimulating the transcription of specific genes. Studies performed using poultry models and PPAR-α–null mice (knockout mice) demonstrated that PPAR-α controls the expression of numerous genes related to lipid metabolism in the liver, including genes involved in mitochondrial β-oxidation, peroxisomal β-oxidation, fatty acid uptake and binding, and lipoprotein assembly and transport.
PPARα regulates the expression of specific genes implicated in metabolic reactions, such as beta-oxidation of fatty acids and regulation of energetic homeostasis due to the secretion of adiponectin. Adiponectin is an adipokine and protein hormone that influences several metabolic functions including glucose and lipid metabolism, glucose utilization, and lipogenesis. It is reported that adiponectin has a direct effect on regulating metabolic pathways in the liver, thereby improving nutrient utilization and body weight gain.
BioCholine – The Energy Repartitioning Agent
In relation to the effect of different sources of choline on chicken performance, a group of researchers reported benefits of supplementing BioCholine to improve weight gain, feed efficiency, and decreased mortality in poultry and swine models. Researchers (Kim et al., 2018) reported BioCholine’s advantage in efficiently upregulating the expression of PPARα and significantly improving the activity of Adiponectin hormone in poultry broilers. BioCholine supplementation to broilers (0-42 days) significantly upregulated key allosteric effectors of hepatic fat and energy metabolism. Kim et al., 2018 also reported the role of BioCholine in growth response in poultry broilers. BioCholine, at a significantly lower level of inclusion, produced significant improvement in the zootechnical performance of broiler chickens and expressed differentially genes related to the hepatic lipogenic, hepatic lipid catabolic pathway, and energy metabolic pathway. In a research study at the University of Georgia, USA, it was validated that BioCholine has the extra advantage of being an energy repartitioning agent. Supplementation of BioCholine at a lower dosage to completely replace 60% of 1 kg choline chloride in broiler rations led to a significant upregulation of marker gene effectors (PK and PEPCK) of the glucose pathway.
Hepatic mRNA Expression of Pyruvate Kinase (PK) Gene: Glycolytic pathway is a fundamental system for energy metabolism. The liver predominantly converts pyruvate, a glycolytic product, into fatty acids via Acetyl CoA. Pyruvate Kinase is a rate-limiting glycolytic enzyme and catalyzes the formation of pyruvate and ATP from phosphoenolpyruvate (PEP) and ADP. With the supplementation of BioCholine in broilers, Pyruvate Kinase (PK) gene expression was significantly upregulated (+159.51%). This validates the advantage of BioCholine in efficient energy utilization.
Hepatic mRNA Expression of PEPCK: Gluconeogenesis is an important metabolic pathway for endogenous glucose generation from substrates such as lactic acid and gluconeogenic amino acids. PEPCK is an important gene, regulating growth by gluconeogenic mechanism/protein deposition in broilers. Trial findings suggest that BioCholine supplementation upregulated hepatic gluconeogenic gene expression, methionine metabolism, and epigenetic gene expression, which involves miRNA-mediated post-transcriptional mechanisms. PEPCK was found to be upregulated in the broilers supplemented with BioCholine (+47.68%). PEPCK gene promoter was found to be hypermethylated in BioCholine supplemented birds, which increases the utilization of amino acids and glucose in growth and muscle formation.
Based on scientific validation reported by Kim et al., 2018, further studies were undertaken by a group of EU researchers who determined the effect of BioCholine on the diet’s apparent metabolizable energy (AME) in growing chickens and roosters. The objective of these experiments was to determine the efficacy of BioCholine on the diet’s AME content. Researchers reported that BioCholine supplementation produced improvements in the use of gross energy (GE), translating into an increase in the diet’s AME content. The improvement ranged from 60 kcal/kg (chickens) to 88 kcal/kg (roosters), at a significantly lower rate of inclusion of BioCholine (for more details of experimental findings and BioCholine dosage, please contact the author).
Summary
In recent years, choline supplementation from natural origin/phytogenics has emerged as an alternative to choline chloride, the standard ingredient used in the animal production industry. BioCholine, the natural choline supplement, is a global brand that is widely used in poultry and swine diets across 50+ countries. Usage of BioCholine not only provides benefits to prevent fatty liver in birds but also optimizes hepatic metabolic processes for efficient fat and energy utilization besides offering great cost and space optimization in the ration.
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