As the SWC of the diets increased, linear increases in the SWC of the stomach digesta (P <0.01) and. Scaled feed intake (SFI) decreased linearly with an increase in dietary SWC (P < 0.001).
Background
Little research has been conducted to assess the effects of fibrous diets on changes in physicochemical properties and composition of the digesta. To predict voluntary feed intake, changes in the physico-chemical properties of digestion along the intestinal segments should be considered (Canibe and Bach Knudsen, 2002; Anguita et al. claimed that the water-holding capacity of the feed affects the intestinal capacity.
Justification
Water holding capacity and swelling capacity of the digestive system are related to the surrounding medium conditions (eg pH, ionic strength and minerals), and these may vary with the GI tract segments. The effect of other physicochemical characteristics of the digestive system, especially in the stomach, should be investigated.
Objectives
To better understand the influence of physicochemical properties of feed in pigs, it is necessary to use a wide range of fiber sources.
Hypotheses
Effects of distillers dried grains with solubles and dietary fiber on the intestinal health of young pigs and chicks. Physicochemical characteristics of food and the digestion of starch and dietary fiber during intestinal transit.
Introduction
Definition of dietary fibre
Dietary fiber can also be viewed as the sum of dietary non-starch polysaccharides (NSP) and lignin compounds of plant cell walls (Wenk, 2001; Banino, 2012). Non-starch polysaccharides (NSP) are partially digested in the intestine, while lignin is a complex indigestible polymer deposited in cell walls.
Use of fibrous agro-industrial by-products as ingredients for pig feeds
Dietary fiber sources are cheap, easily available by-products from feed production and are well accepted by pigs (Bakare et al., 2013; Ndou et al., 2013). The benefits of including dietary fiber in pig diets are slowly being recognized (Bindelle et al., 2008).
Physicochemical properties of dietary fibre matrices
- Water holding capacity
- Swelling capacity
- Viscosity
- Water binding capacity and absorption
- Solubility
Technically, WHC describes the amount of water that can be retained or absorbed by a known amount of fiber under known or used conditions (Guillon and Champ, 2000; Elleuch et al., 2011). Factors such as glycosidic linkage between monosaccharides and functional groups such as sulfates and carboxyl (COOH) are the main determinants of fiber solubility (Elleuch et al., 2011).
Effects of physical properties of fibrous diets on feed intake
Water-holding capacity slows gastric emptying, due to its function to prolong digestion retention time (Bindelle et al., 2008). As the WHC of dietary fiber increases, more space is required, thereby reducing food intake (Tsaras et al., 1998).
Influence of physical properties of fibrous diets on digestion
The absorption of SCFA in growing pigs occurs rapidly in the large intestine and contributes up to 24% of maintenance energy supply (Canibe and Bach Knudsen, 2002; Montagne et al., 2003). Soluble dietary fiber generally ferments easily, quickly and completely in the large intestine compared to insoluble dietary fiber (Bach Knudsen, 2001).
Effects of physical properties of fibrous diets on gut size development
The digestibility of fiber in the small intestine ranges from 10 to 62%, depending on the source and level of dietary fiber inclusion and the age of the pig (Bach Knudsen et al., 2001). In the hindgut, the cecal and colonic microflora produce short chain fatty acids (SCFA), lactic acid, water, gases (carbon dioxide, hydrogen, methane), bacterial biomass and heat (Gdala et al., 1997; Bach Knudsen, 2001; Montagne et al. al., 2003; Anguita et al., 2006). Slow bowel emptying gives the fiber matrix more time to promote mucosal size development and intestinal hypertrophy (Ngoc et al., 2012).
Another possible cause of intestinal size development is the production of SCFAs, which affect intestinal growth by stimulating epithelial cell proliferation (Jørgensen et al., 1996; Freire et al., 2000).
Gut health and welfare
The main properties, especially the physicochemical properties, of dietary fiber are related to visceral hypertrophy (Stanogias and Pearce, 1985).
Summary
Effect of dietary fiber source on total tract digestibility, cecal volatile fatty acids and digestion time in the weaned piglet. The influence of dietary fiber source and level on digestive tract development, digestibility and energy metabolism in broilers. The aim of the present study was to determine the effects of incorporating graded levels of maize cob meal in diet on the physicochemical properties of digestive system and sizes of gastrointestinal organs in growing pigs.
The WHC of digesta in the stomach, ileum and cecum decreased (P<0.05) with corn cob inclusion level.
Introduction
As a result, when included in pig feed, it does not significantly reduce feed intake and growth performance (Ndou et al., 2013b). Maize cobs are also a ready source of available non-starch polysaccharides for microbial fermentation (Ndou et al., 2013a). Water-holding capacity, viscosity and swelling capacity (SWC) induce direct effects of dietary fiber that affect the availability of nutrients during transit in the intestine (Högberg and Lindberg, 2004; Anguita et al., 2007).
The weight response of different intestinal segments, as well as digesta, to increased fiber inclusion also helps explain the role of dietary fiber in pig intestinal health and welfare (Ngoc et al., 2012).
Materials and Methods
- Ethical consideration
- Study site
- Pigs and housing
- Experimental diets and feeding management
- Measurement of digesta and pig performance
- Determination of physicochemical properties of diets and digesta
- Statistical analyses
The feed conversion ratio (FCR) for each pig was calculated as the ratio of the amount of feed consumed to the ADG. Half of the collected samples were first freeze-dried and then dried at 103°C for dry matter (DM) analysis. The water holding capacity of the digesta samples was determined as the weight lost after the samples were dried at 103 °C for 20 h.
Stepwise regression in SAS (2008) was used to identify physicochemical properties of the digestive system that influenced the weights of the segments.
Results
Pig performance, segment contents and segment weights
Regression analysis was also used to determine the relationship between the level of corncob inclusion and the physicochemical properties (pH, water concentration, WHC and SWC) of the digestate in each segment.
Physicochemical characteristics of the digesta
Digestive water concentration during the transition from the stomach to the ileum of pigs fed the control diet increased more rapidly compared to that of pigs fed a corncob meal-based diet of 80 and 160 g/kg.
Discussion
Inclusion of corncob level increased the SWC of digesta in the stomach and ileum at a higher rate than in the proximal colon. The inclusion level of corn on the cob reduced WHC in the digesta in the stomach, ileum and cecum. The water concentration in the stomach in relation to the corncob inclusion level showed the same.
Interestingly, 80 and 160 g/kg corncob diets rapidly reduced hindgut water concentration compared to the basal diet.
Conclusions
An increase in corncob levels decreased water concentration in the distal colon, probably due to the primary function of the colon to actively absorb water and sodium ions against the electrochemical gradient (Williams et al., 2001; Anguita et al., 2007). The increase in water concentration along the intestine in pigs on the basal diet reflected a high digestibility of starch fraction in the foregut compared to the hindgut (Bach Knudsen, 2001; . Molist et al., 2009).
Effects of insoluble and soluble dietary fiber on digestive physicochemical properties and microbial activity in early weaned pigs. As the SWC of the diets increased, linear increases in digesta SWC were observed in the stomach (P < 0.01) and cecum (P < 0.001). There was a negative linear relationship (P < 0.01) between finishing pig SFI and digesta SWC.
The swelling capacity of diets and stomach digestion are accurate descriptors of graded food intake.
Introduction
Materials and Methods
- Study site
- Pigs and housing
- Diets
- Measurements
- Determination of physicochemical properties of diets and digesta
- Statistical analyses
Stepwise regression in SAS (2008) was used to identify physicochemical properties of the diets that affected intestinal segment weights. The quadratic response surface model (PROC RSREG) procedure of SAS (2008) was used to determine the relationship between the weight of the stomach, ileum, cecum, proximal colon and distal colon and each of the physicochemical properties of the diet selected using stepwise regression. The correlation between WHC and SWC of digestion in each intestinal segment was analyzed using Pearson's correlation (PROC CORR) from SAS (2008).
RSREG (SAS, 2008) was used to determine the type of relationship between SFI and each of the selected hydration properties.
Results
- Effect of inclusion level of fibre on pig performance
- Effects of physicochemical properties of the diet on segment weights
- Effects of hydration properties of the diet on hydration properties of digesta in each
- Correlations between hydration properties of the digesta in gut segments
- Prediction of scaled feed intake from the physicochemical properties of the diets
The water-holding capacity of the diet had no effect on WHC of digesta in the stomach, ileum and cecum (P > 0.05). Diet SWC did not affect digestive SWC in the ileum, proximal colon, and distal colon. There were no significant correlations between WHC and SWC of digesta in the large intestine and distal intestine.
No association was observed between WHC of the digestive tract and SFI in the stomach (P > 0.05).
![Table 4.4: Effect of the physicochemical properties of the diet on segment weights Item Model [segment weight = ax 2 +bx+c+e]](https://thumb-ap.123doks.com/thumbv2/pubpdfnet/10643895.0/76.892.107.785.144.432/table-effect-physicochemical-properties-segment-weights-model-segment.webp)
Discussion
The observation that intestinal weight decreased with dietary SWC suggests that during the passage of digesta into the intestine, various biochemical changes occur in the foregut. The increase in proximal colon weight with an increase in NDF content was consistent with the literature (Len et al., 2009; Ngoc et al., 2012). The finding that dietary WHC was unrelated to digestive WHC in the stomach, ileum, and cecum was not expected.
The WHC of the diet and that of the digesta in the proximal and distal colon were positively correlated.
Conclusions
The decrease in SFI observed with increasing SWC of gastric digestion also supports the hypothesis that volume was limited by intestinal filling as the gastrointestinal tract expanded. The finding that the rates of reduction in SFI were pronounced as the bulking capacity of the diet increased as the capacity of gastric digestion confirmed that the physicochemical properties of digestion varied from one segment to another. The difference in these rates of reduction further indicates that the elastic limit at which feed molecules swell decreases along the gut.
The water holding capacity of three starchy legumes in the raw, cooked and fiber-rich fraction form. Intrinsic ability of the fecal microbial flora to ferment dietary fiber at different growth stages of pigs. Effects of physical properties of feed on the microbial ecology and survival of Salmonella enterica serovar Typhimurium in the gastrointestinal tract of pigs.
Water holding capacity of insoluble fiber reduces free water and increases digestive viscosity in the rat.
General discussion
The mechanisms by which the physicochemical properties of digesta in growing pigs may be different for finishing pigs. Scaled feed intake (SFI), defined as ADFI expressed as a proportion of pig body weight, decreased as SWC increased. As the feed components swell, they absorb water and increase in size, which inevitably reduces the bulk density of the feed.
The finding that the rates of decrease in SFI were more pronounced when the swelling capacity of the diet increased than that of gastric digestion confirms that the physicochemical properties of digestion vary along the gut.
Conclusions
It was hypothesized that the relationship between the physicochemical properties of diets and digestion in growing pigs would be different from that in finishing pigs. Unlike fattening pigs, corn cobs, sunflower husks, citrus pulp and alfalfa hay were used as fiber sources for fattening pigs (Chapter 4). Reduction in SFI with increase in digestive SWC in the stomach also supports the assumption that volume was limited due to intestinal filling as digestion expands.
The influence of physicochemical properties of diets and digestion in growing pigs is different from that in finishing pigs.
Recommendations and further research
