Toward Precise Nutrient Value of Feed in Growing Pigs: Effect of Meal Size, Frequency and Dietary Fibre on Nutrient Utilisation

Abstract

Nutritional values of ingredients have been and still are the subject of many studies to reduce security margins of nutrients when formulating diets to reduce feed cost. In most studies, pigs are fed a limited amount of feed in a limited number of meals that do not represent how pigs are fed in commercial farm conditions. With free access to feed, pigs follow their intrinsic feeding behaviour. Feed intake is regulated by satiety and satiation signals. Reducing the feed intake level or feeding frequency can affect digestibility and transit time and induce metabolic changes. To reduce feed costs, alternative ingredients that are frequently rich in dietary fibre are added to diets. Fibre acts on the digestion process and transit time by decreasing energy density and causing viscosity. Various analyses of fibre can be realised, and the measured fibre fraction can vary. Exogenous enzymes can be added to counteract the effect of fibre, but digestive tract conditions, influenced by meal size and frequency, can affect the efficiency of supplemented enzymes. In conclusion, the frequency and size of the meals can affect the digestibility of nutrients by modulating gastrointestinal tract conditions (pH and transit time), metabolites (glucose and short-chain fatty acids) and hormones (glucagon-like peptide 1 and peptide tyrosine tyrosine).

Keywords: dietary fibre; digestibility; exogenous enzymes; feed intake; growing pigs; meal frequency; meal size; transit time.

Figure 1

Dietary fibres determination methods and the fractions they include (adapted from NRC 2012) Errows represent the dietary carbohydrates that are included in the analysis (Weende analysis only includes part of the cellulose).

Figure 2

NSP and their physiochemical properties (adapted from Bautil and Courtin, 2019 [107]). Errows represent a scale of viscosity and fermentability. AXOS: arabinoxylooligosaccharides, OS: oligosaccharides, WE-AX: water-extractable arabinoxylan, WU-AX: water unextractable arabinoxylan.