An in vitro and in vivo approach to characterize digesta from pigs fed different forms of pea flour.

In vitro models of digestion are useful tools to explore the behavior of dietary fiber sources in gastrointestinal conditions. To evaluate the validity of our digestion model, digesta obtained in vivo and in vitro were characterized and the impact of cell wall integrity on protein bioaccessibility and digestibility evaluated. Six cannulated barrows [Pietrain × (Large White × Landrace)] were included in a 2 × 2 Latin square design where they were fed two diets identical in chemical composition but differing in nutrient bioaccessibility.

Apparent jejunal amino acid digestibility, gut morphology, and the expression of intestinal amino acid transporters in pigs fed protein or free amino acids.

Dietary amino acids (AA) supplied as protein or in free form are not only digested and absorbed at different rates but can also induce differences in the intestinal physiology of pigs. We compared the apparent jejunal AA digestibility, intestinal morphology, and gene expression of AA transporters of pigs fed diets providing different forms of AA. Thirty growing pigs (33.

A dynamic mammary gland model describing colostrum immunoglobulin transfer and milk production in lactating sows.

The physiology of the sow mammary gland is qualitatively well described and understood. However, the quantitative effect of various biological mechanisms contributing to the synthesis of colostrum and milk is lacking and more complicated to obtain. The objective of this study was to integrate physiological and empirical knowledge of the production of colostrum and milk in a dynamic model of a single sow mammary gland to understand and quantify parameters controlling mammary gland output.

Skeletal muscle proteome of piglets is affected in a muscle-dependent manner by a limiting total sulfur amino acid supply.

Purpose: A total sulfur amino acid (TSAA) deficient diet can affect the amino acid composition of skeletal muscles. However, it is unknown how the different muscle proteins are affected by the TSAA deficiency.

Methods: The proteomic profiles of the fast-twitch glycolytic longissimus (LM) and the slow-twitch oxidative rhomboideus (RM) muscles were compared in 42-day-old piglets fed either a 28% deficient (TSAA-) or a sufficient (TSAA+) diet in TSAA for 10 days.

Metabolizable energy requirement for maintenance estimated by regression analysis of body weight gain or metabolizable energy intake in growing pigs.

Objective: Feed energy required for pigs is first prioritized to meet maintenance costs. Additional energy intake in excess of the energy requirement for maintenance is retained as protein and fat in the body, leading to weight gain. The objective of this study was to estimate the ME requirements for maintenance (MEm) by regressing body weight gain against ME intake (MEI) in growing pigs.

Methionine to cystine ratio in the total sulfur amino acid requirements and sulfur amino acid metabolism using labelled amino acid approach for broilers.

Background: Assuming that part of Methionine (Met) is converted into Cystine (Cys), but ignoring the rates with which such phenomenon occurs may lead to an excessive supply of Met in poultry diets. Such inconvenient could be easily avoided with the knowledge of the ideal Met:Cys/Total sulfur amino acids (TSAA) ratio and the rates of Met conversion into Cys.

Results: Met sources did not affect performance.

Integrative analysis of indirect calorimetry and metabolomics profiling reveals alterations in energy metabolism between fed and fasted pigs.

Background: Fasting is a simple metabolic strategy that is used to estimate the maintenance energy requirement where the energy supply for basic physiological functions is provided by the mobilization of body reserves. However, the underlying metabolic components of maintenance energy expenditure are not clear. This study investigated the differences in heat production (HP), respiratory quotient (RQ) and plasma metabolites in pigs in the fed and fasted state, using the techniques of indirect calorimetry and metabolomics.

A systemic approach to explore the flexibility of energy stores at the cellular scale: Examples from muscle cells.

Variations in energy storage and expenditure are key elements for animals adaptation to rapidly changing environments. Because of the multiplicity of metabolic pathways, metabolic crossroads and interactions between anabolic and catabolic processes within and between different cells, the flexibility of energy stores in animal cells is difficult to describe by simple verbal, textual or graphic terms. We propose a mathematical model to study the influence of internal and external challenges on the dynamic behavior of energy stores and its consequence on cell energy status.

Splanchnic tissues respond differently when piglets are offered a diet 30 % deficient in total sulfur amino acid for 10 days.

Purpose: A deficient total sulfur amino acid (TSAA) supply has been reported to differently affect the amino acid composition of tissues, but limited information is available about its effects on the morphology and metabolic properties of splanchnic tissues.

Methods: The amino acid composition, protein metabolism, glutathione concentration of the liver, proximal and distal jejunum, ileum and kidneys, and intestinal architecture were compared in 42-day-old piglets pair-fed either a diet deficient (TSAA-; 28 % deficiency) or sufficient (TSAA+) in TSAA for 10 days.

Results: The supply of TSAA had no effect on tissue weights, but influenced the amino acid composition in a tissue-dependent manner.

A Methionine Deficient Diet Enhances Adipose Tissue Lipid Metabolism and Alters Anti-Oxidant Pathways in Young Growing Pigs.

Methionine is a rate-limiting amino-acid for protein synthesis but non-proteinogenic roles on lipid metabolism and oxidative stress have been demonstrated. Contrary to rodents where a dietary methionine deficiency led to a lower adiposity, an increased lipid accretion rate has been reported in growing pigs fed a methionine deficient diet. This study aimed to clarify the effects of a dietary methionine deficiency on different aspects of tissue lipid metabolism and anti-oxidant pathways in young pigs.

Concept and application of ideal protein for pigs.

Knowledge about the amino acid requirements and the response of pigs to the amino acid supply is essential in feed formulation. A deficient AA supply results in a reduction in performance while an oversupply is costly and leads to excessive nitrogen excretion with a potentially negative environmental impact. Amino acid requirements are determined to a large extent by the protein deposition in the body and, for lactating sows, by the protein exported in the milk.

Skeletal muscles respond differently when piglets are offered a diet 30% deficient in total sulfur amino acid for 10 days.

Purpose: Although amino acids (AA) are required for growth, little is known about the effect of a deficient AA supply on the composition and the contractile and metabolic properties of skeletal muscles.

Methods: Protein metabolism, oxidative catabolism, glutathione system, and fiber-type composition of the longissimus (LM), rhomboideus (RM), and semitendinous (SM) muscles were compared between 42-day-old piglets pair-fed for 10 days either with a diet with a 28% deficient supply of total sulfur AA (TSAA-) or with a diet with a sufficient supply of total sulfur AA (TSAA+).

Results: The relative weight, protein mass, and protein synthesis of LM were 10-32% lower in TSAA- pigs compared with TSAA+ pigs, while RM and SM were not affected by the TSAA supply.

Using a large-scale knowledge database on reactions and regulations to propose key upstream regulators of various sets of molecules participating in cell metabolism.

Background: Most of the existing methods to analyze high-throughput data are based on gene ontology principles, providing information on the main functions and biological processes. However, these methods do not indicate the regulations behind the biological pathways. A critical point in this context is the extraction of information from many possible relationships between the regulated genes, and its combination with biochemical regulations.

Exploring metabolism flexibility in complex organisms through quantitative study of precursor sets for system outputs.

Background: When studying metabolism at the organ level, a major challenge is to understand the matter exchanges between the input and output components of the system. For example, in nutrition, biochemical models have been developed to study the metabolism of the mammary gland in relation to the synthesis of milk components. These models were designed to account for the quantitative constraints observed on inputs and outputs of the system.

Partitioning of heat production in growing pigs as a tool to improve the determination of efficiency of energy utilization.

In growing pigs, the feed cost accounts for more than 60% of total production costs. The determination of efficiency of energy utilization through calorimetry measurements is of importance to sustain suitable feeding practice. The objective of this paper is to describe a methodology to correct daily heat production (HP) obtained from measurements in respiration chamber for the difference in energy expenditure related to physical activity between animals.

Maintenance energy requirements of growing pigs and calves are influenced by feeding level.

The conventional regression method for partitioning heat production (HP) in growing animals between HP associated with either maintenance or growth assumes maintenance HP to be independent of feeding level (FL). However, there are indications that this assumption is not correct and an alternative method is proposed in this study from a reanalysis of 3 trials. In trial 1, 73-, 152-, and 237-kg calves received one milk replacer at 77, 84, 92, and 100% of their ad libitum metabolizable energy (ME) intake.

Oxidation of dietary stearic, oleic, and linoleic acids in growing pigs follows a biphasic pattern.

We used the pig as a model to assess the effects of dietary fat content and composition on nutrient oxidation and energy partitioning in positive energy balance. Pigs weighing 25 kg were assigned to either: 1) a low fat-high starch diet, or 2) a high saturated-fat diet, or 3) a high unsaturated-fat diet. In the high-fat treatments, 20% starch was iso-energetically replaced by 10.

Fasting heat production and energy cost of standing activity in veal calves.

Metabolic body size of veal calves is still calculated by using the 0.75 exponent and no data were available to determine energy cost of physical activity during the whole fattening period. Data from two trials focusing on protein and/or energy requirements were used to determine the coefficient of metabolic body size and the energy cost of standing activity in male Prim'Holstein calves.

Digesta transit in different segments of the gastrointestinal tract of pigs as affected by insoluble fibre supplied by wheat bran.

Digestibility is the result of two competing processes: digestion and digesta transit. To develop or parameterise mechanistic models of digestion, both processes have to be quantified. The aim of this study was to determine the effect of insoluble dietary fibre on the transit in the gastrointestinal tract of pigs.

Deposition of dietary fatty acids, de novo synthesis and anatomical partitioning of fatty acids in finishing pigs.

Predicting aspects of pork quality becomes increasingly important from both a nutritional and technological point of view. The aim of the present study was to provide quantitative information on the relation between nutrient intake and whole-body fatty acid (FA) depositions. This information is essential to develop mechanistic models predicting the FA content of tissues.

Previous feeding level influences plateau heat production following a 24 h fast in growing pigs.

Factorial approaches to estimate energy requirements of growing pigs require estimation of maintenance energy requirements. Heat production (HP) during fasting (FHP) may provide an estimate of maintenance energy requirements. Six barrows were used to determine effects of feeding level on components of HP, including extrapolated plateau HP following a 24 h fast (FHPp).

Deposition of dietary fatty acids and of de novo synthesised fatty acids in growing pigs: effects of high ambient temperature and feeding restriction.

Predicting aspects of pork quality becomes increasingly important from both a nutritional and a technological point of view. Little information is, however, available concerning the quantitative relation between nutrient intake and fatty acid (FA) deposition at the whole-animal level. In this study, eight blocks of five littermate barrows were used in a comparative slaughter trial.

Modeling biochemical aspects of energy metabolism in mammals.

A framework representing the major biochemical pathways of nutrient metabolism is developed allowing quantification of the energy efficiency of different nutritional scenarios. The model is based on a number of carbon chain pivots (glucose, pyruvate, acetyl coenzyme A, alpha-ketoglutarate, oxaloacetate and serine) and cofactors involved in metabolism. Excess pivots yield acetyl coenzyme A, which may be used for ATP or lipid synthesis.