Nutrition of Pigs Kept Under Low and High Sanitary Conditions Effects on Amino Acid and Energy Metabolism and Damaging Behaviour
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Nutrition of pigs kept under low and high sanitary conditions Effects on amino acid and energy metabolism and damaging behaviour Yvonne van der Meer Nutrition of pigs kept under low and high sanitary conditions Effects on amino acid and energy metabolism and damaging behaviour Yvonne van der Meer Thesis committee Promotor Prof. Dr W. J. J. Gerrits Personal chair at the Animal Nutrition Group Wageningen University & Research Co-promotors Dr A. J. M. Jansman Senior researcher, Animal Nutrition Wageningen University & Research Dr A. Lammers Researcher, Adaptation Physiology Group Wageningen University & Research Other members Prof. Dr J. Keijer, Wageningen University & Research Dr E. Labussière, INRA, Rennes, France Prof. Dr C.M. Nyachoti, University of Manitoba, Canada Prof. Dr S.A. Edwards, University of Newcastle, United Kingdom This research was conducted under the auspices of the Graduate School of Wageningen Institute of Animal Science (WIAS) Nutrition of pigs kept under low and high sanitary conditions Effects on amino acid and energy metabolism and damaging behaviour Yvonne van der Meer Thesis submitted in fulfilment of the requirements for the degree of doctor at Wageningen University by the authority of the Rector Magnificus, Prof. Dr. A. P. J. Mol, in the presence of the Thesis Committee appointed by the Academic Board to be defended in public on Friday 7 July 2017 at 4 p.m. in the Aula. Yvonne van der Meer Nutrition of pigs kept under low and high sanitary conditions Effects on amino acid and energy metabolism and damaging behaviour, 182 pages. PhD thesis, Wageningen University, Wageningen, the Netherlands (2017) With references, with summary in English ISBN 978-94-6343-197-2 DOI http://dx.doi.org/10.18174/413888 Table of contents Chapter 1 General introduction 9 Chapter 2 Performance of pigs kept under different sanitary 25 conditions affected by protein intake and amino acid supplementation Chapter 3 A link between damaging behaviour in pigs, sanitary 57 conditions, and dietary protein and amino acid supply Chapter 4 Low sanitary conditions increase maintenance energy 85 expenditure and decrease incremental protein efficiency in growing pigs Chapter 5 Diurnal patterns of heat production and oxidation of 111 carbohydrate and fat in pigs kept under different sanitary conditions Chapter 6 General discussion 131 List of abbreviations 165 Summary 167 Acknowledgements 171 About the author Curriculum vitae 175 List of publications Training and supervision plan Colophon 182 Chapter 1 General introduction Chapter 1 DIETARY REQUIREMENTS OF GROWING PIGS Feed costs are a large proportion of the total costs for pig production. It is therefore of economic importance to match the dietary nutrient supply to the nutrient requirements of a pig as closely as possible. Recommendations for nutrient requirements of a pig are presented using several nutrient and energy evaluation systems (ARC, 1981; Whittemore et al., 2003; Santioga Rostagno et al., 2011; NRC, 2012; CVB, 2016). Mostly a concept is used that splits requirements for growing pigs in a part for maintenance and production (growth) purposes. The definition of maintenance is the level of feeding at which the requirements for nutrients are just met to ensure the continuity of vital processes so that there is no net gain or loss of nutrients in tissue and animal products (ARC, 1981). Requirements for maintenance and growth are both measured under experimental conditions. Protein requirements of growing pigs. In practice, the dietary protein level of growing pigs typically decreases during the life of a pig when phase feeding is used. This reduction in dietary protein level follows the efficiency of a pig to use dietary protein for depositing protein tissue in the body. In Figure 1.1 is indicated how efficient the dietary protein is used by the pig to deposit protein during its life. This 3-dimensional representation by van Milgen and Noblet (2003) illustrates that the efficiency of a growing pigs reduces when it becomes more heavy/aged and is also depending on the intake of metabolizable energy (ME). Figure 1.1 The response of protein deposition as a function of ME intake and body weight (BW). The connected points indicate the feed intake capacity (ad libitum intake) of a Large white barrow and corresponding protein deposition. Mem = ME intake for maintenance. Source: van Milgen and Noblet (2003). 10 Chapter 1 Requirement values for dietary protein do not exist in the evaluation systems. Instead, recommendations for dietary amino acid (AA) intake are published (NRC, 2012; CVB, 2016). These AA requirements are determined in pig experiments that use a titration set up or are calculated from experiments with a factorial approach. In titration studies typically the response in performance of pigs to a stepwise increasing or decreasing dietary dose of AA is evaluated using different treatment groups or within the same individual pig in time. For studies with a factorial approach nutrient requirements for maintenance and protein deposition in the body can be calculated by using data obtained in pig experiments. The ileal digestibility of AA is measured in AA requirement studies to evaluate the bio- availability of AA for the pig. There are different expressions for Ileal digestibility, namely apparent, true and standardized ileal digestibility (AID, TID and SID, respectively). The expression used is depending on which proportion of AA outflow is used in the digestibility calculation (Stein et al., 2007). The AID is calculated by subtracting the AA inflow by the total AA outflow including endogenous losses. The endogenous losses can be split into basal (not influenced by feed ingredient composition) and specific (influenced by ingredient composition) endogenous losses. Correcting for total endogenous losses results in the TID and correcting digestibility for basal endogenous losses only, results in the SID (Stein et al., 2007). The AA and nitrogen (N) requirements for maintenance were described by Moughan (2003) as requirements for turnover of body protein, skin and hair AA losses, basal endogenous intestinal AA losses, synthesis of non-protein N-containing compounds, and urinary AA losses. The first three processes are considered to be quantitatively important for requirements for maintenance. The AA composition of the whole body protein can be used as the basis for an ideal AA profile for protein deposition as was suggested by Whittemore (1983). Several pig growth models have been developed, which simulate the AA uptake, metabolism and nutrient partitioning for growing pigs (Whittemore and Fawcett, 1974; Moughan, 1981; Whittemore, 1983). To estimate the biological maximal rate of body protein retention (Pdmax) net rates of body protein retention are determined under optimal dietary and environmental conditions (Moughan, 2003). Under practical farming conditions, which can be less optimal, this Pdmax is not that commonly reached, due to factors such as subclinical disease, thermal environment, and social conditions (Burrin et al., 2001). Energy requirements of growing pigs. The energy that is ingested by an animal as feed is deposited as fat or protein, excreted in faeces and urine, or dissipated as heat. The dissipation of heat by a pig might represent more than 50% of the ingested energy (van Milgen and Noblet, 2000), which can be seen as the major part of inefficiency. It is therefore of major importance to better understand and quantify the energy requirements of pigs. Quantification of heat production helps to better understand the daily energy 11 Chapter 1 balance of an animal. The dissipation of heat or the heat production of a pig can be measured by indirect calorimetry. When nutrients are oxidized, O2 is consumed and CO2 produced. Heat production can be calculated from the combination of O2 consumption, CO2 production (and urinary N and CH4 production) according to Brouwer (1965). These components can be measured by placing the animals in respiration chambers, were the gas exchanges can be measured and used for calculation of heat production. The total heat production of an animal can be split in heat production due to physical activity, thermic effect of feeding (TEF) and fasting heat production. production (Figure 1.2). The TEF can be split in a short and a long TEF. The short TEF is the heat production associated with a meal, related to nutrient digestion and absorption (van Milgen et al., 1998; van Milgen and Noblet, 2000) and the long TEF is the heat production due to “long-term” metabolic processes, including protein and lipid synthesis (van Milgen et al., 1998; van Milgen and Noblet, 2000). The fasting heat production (FHP) also called ‘basal’ metabolism is defined as the rate of energy expenditure of a non-reproductive, healthy, fasting, and a resting adult in thermo-neutral zone, in an inactive phase of the day (McNab, 1997; Labussière et al., 2008). The FHP is used as a proxy for energy requirement for maintenance. Overall it remains difficult to measure FHP in growing animals. 2500 physical activity 1) - short term TEF 2000 06 · d 06 · long term TEF - fasting heat production 1500 1000 500 Heat production (kJ · BW · (kJ production Heat 0 2:00 4:00 6:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 Time (h) Figure 1.2 Heat production of a group of restricted fed growing pigs partitioned in different components of heat. Feed was offered in two different meals at 7:30 and 15:30. TEF = thermic effect of feeding. Based on own data. There is already a lot of knowledge about the requirements for AA and energy in growing pigs. This information is based on pig experiments were pigs are kept under experimental conditions for the mentioned measurements, which means a clean environment, low animal density, and high attention of caretakers. These experimental conditions can therefore be considered as optimal conditions for a pig. There is not much known, however, about nutrient requirements of pigs kept in suboptimal conditions.