76 Table 4.2: Chemical composition of basal diet (B) and diet based on alfalfa hay (LC), corn cob (MC), corn stover (MS), sawdust (SD), sunflower husk (SH) and grass (VG) on different levels of involvement. 87 Table 4.6: Prediction of average daily gain (ADG), scaled average daily gain (SADG) and feed conversion efficiency (FCE) using physico-chemical properties of fibrous feed.
General Introduction
- Background
- Justification
- Objectives
- Hypotheses
- References
The amount of feed that can be consumed by a pig is undoubtedly determined by physicochemical measures of the feed mass and the intestinal capacity of the pig. The broad objective of the present study was to determine physico-chemical properties of a feed that best describe the extent of the feed, so that the intestinal capacity of a pig can be predicted.
Literature review
Introduction
Physicochemical measurements of bulkiness
- Water holding capacity
- Bulk density
- Neutral detergent fibre
- Crude fibre
- Viscosity
- Solubility
- Swelling capacity
However, fattening pigs have the ability to ferment the fiber content of the feed in the large intestine (Bindelle et al., 2008). There is little knowledge about the effects of the swelling capacity of the feed on feed intake.
Factors affecting voluntary feed intake in growing pigs
- Animal factors
- Dietary factors
- Environmental factors
However, as pigs' body weight increases, their ability to utilize the fibrous ingredients also improves (Kyriazakis and Emmans, 1995; Tsaras et al., 1998). The effect of the extent of the feed in relation to changes in temperature on VFI is not well established.
Attributes of dietary fibre in growing-finishing pigs
- Promotion of animal welfare
- Enhancement of gut health and microbial populations
- Reduction of gaseous emissions and nutrient losses to the environment
- Reducing the need for grain and feed costs
- Enhancement of crop-livestock production systems
- Promoting sustainability of pig production and utilisation of resources
- Promotion of outdoor pig production systems
As a result, the presence of DF changes the microbial balance in the intestines with a beneficial effect on the intestinal health and the physiological status of the pig (Bindelle et al., 2008). It is therefore necessary to investigate the effect of the physical properties of DF and identify the appropriate inclusion levels that promote the growth of microbes with beneficial effects on gut health without compromising the nutritional intake of growing pigs.
Common fibrous feed ingredients in southern Africa
- Cereal by-products
- Leguminous residues
- Agro-industrial by-products
- Forage plants
Cereal by-products are main sources of cellulose, lignin and hemicellulose and their usefulness has been extensively investigated, especially in ruminants (Tolera and Sundstol, 2001; Abdou et al., 2011). Fibrous feed ingredients of fruit and legume origin can be wastes derived from citrus fruits, soybean and peanut residues after extraction of juice and cooking oil respectively (Borchani et al., 2011).
Estimation of gut capacity in growing pigs
To enable threshold levels of intake to be identified for each physicochemical measurement of volume, it is necessary to use a wide variety of fiber sources and potentially include them in diets with different intake levels. In this regard, a broader range of each physicochemical property can then be applied to establish the threshold values of measures of volume that can be used to identify the point at which an equilibrium uptake is reached or begins to increase as the bulky content of the feed continues to rise. increase. Although quadratic equations can be used to predict changes in VFI as each physical trait increases, broken stick models are likely to provide more accurate levels for estimating intestinal capacity in pigs.
Summary
Carbohydrates in the diet change the fecal composition and pH and the ammonia emission from the slurry of growing pigs. Feeding spinach or sweet potato leaves and the growth performance of growing pigs remained stable. Voluntary feed intake in finishing pigs: a review of the main determinants and possible approaches for accurate predictions.
Physical properties, chemical composition and fermentation characteristics of feed
Introduction
Conventional diets predispose pigs to gut health problems, impair animal well-being and escape the GIT, thereby causing nutrient loss to the environment (Aarnink and Verstegen; 2007; Bindelle et al., 2008; Jorgensen et al., 2010). Physicochemical measurements of bulk, such as solubility, viscosity, water holding capacity (WHC), bulk density, fiber content, rate of ruminal degradation, rate at which long particles are reduced to smaller particles, partition factors, amount of short-chain fatty acids (SCFA) produced during fermentation and efflux rates are important factors affecting the intake of bulky feeds (Orskov, 1994; Tsaras et al., 1998; Borchani et al., 2011). The available literature on physicochemical properties of bulky diets is based on limited materials (Tsaras et al., 1998; Anguita et al., 2007; Behgar et al., 2009).
Materials and Methods
- Feed ingredients
- Chemical composition
- Determination of water holding capacity
- Determination of bulk density
- In vitro organic matter disappearance and gas production
- Statistical analyses
The aim of the present study was therefore to characterize physicochemical properties and fermentation profiles of common fiber feed ingredients. To calculate the density, unit mass of the feed ingredient was expressed per unit volume of water displaced (g/ml). Fecal collection and inoculum preparations were performed according to modifications of the method proposed by Wang et al.
Results
- Chemical composition and bulk characteristics of non-fibrous feedstuffs
- Physicochemical properties and fermentation parameters of fibrous feedstuffs
For the first 8 h of incubation, corncobs had the greatest rate (P < 0.001) of gas production. The fastest rate of gas production (P < 0.001) during the 16- to 24-h period occurred for corn and alfalfa cobs. The overall rate of gas production was increased (P < 0.05) in rice bran and alfalfa hay.
Discussion
The difference in WHC of the fibrous sources can be attributed to the fact that exposure of hydrophilic binding sites within the fiber matrix varies with fiber types mainly due to the difference in the polysaccharide building block that forms the structure of those feeds (Elleuch et al., 2011). The negative correlation between WHC and EE content can be attributed to the presence of the non-bound fats within the matrix of fibers forming sheaths covering the water binding sites. It can therefore be assumed that there may be other properties of the fiber that promote fermentation.
Conclusions
Prediction of the total digestibility of energy in feed materials and pig feeds by in vitro analyses. In vitro evaluation of the fermentation fractions of barley and other grains in the gastrointestinal tract of pigs. Fermentation of nonstarch polysaccharides in mixed diets and single fiber sources: comparative studies in human subjects and in vitro.
Prediction of gut capacity in weaner pigs with the use of the physicochemical
Introduction
Prediction of the intestinal capacities of growing pigs facilitates the nutritionally and economically accurate formulation of feeds. Because adding bulky feed is likely to limit nutrient intake, intestinal capacity can be estimated from the physicochemical properties of the feed. The aim of the study was to determine the physicochemical properties of a feed that best describe the bulkiness of the feed, so that the intestinal contents of a weaned pig can be predicted using this measurement.
Materials and Methods
- Description of study site
- Pigs and housing
- Feeds
- Experimental design and management of pigs
- Statistical analyses
The goal was to select fiber sources with as wide a range of physical-chemical properties as possible. The weight of the feed consumed each week was divided by 7 to determine the average daily feed intake (ADFI). The effects of pig age (week), fiber source, fiber inclusion level, batch and their interactions on SFI were determined using the GLM procedure (SAS, 2008).
Results
- Effects of fibre source, and inclusion level and week on scaled feed intake
- Physicochemical properties of fibrous feeds affecting intake, weight gain and feed
- Prediction of feed intake and estimation of gut capacity
- Prediction of weight gain and feed conversion efficiency
An increase in bulk density of the forage was associated with a linear decrease in SFI (P < 0.001). Comparisons for prediction of GDT, SADG and FCE using physico-chemical properties of the feeds are shown in Table 4.6. There was a linear increase (P < 0.001) in FCE as the crude protein content of the diets increased.
Discussion
Therefore, it is imperative to evaluate the WHC changes of maize cob digestion along the gut. Water holding capacity measures a feed's ability to hold water, so a diet with a high WHC can hold more water and take up more space in the gut. Using the broken rod model, the optimal WHC value of forage, where intake was limited by intestinal capacity, was 4.53 g water/g dry matter.
Conclusions
The decrease in SADG as bulk content of the diet increased suggests that the high WHC limited nutrient consumption. Another plausible explanation for the reduction in SADG as the size of the diets increases is that the low energy content of fiber feeds promotes early satiety, thereby limiting growth performance (Wenk, 2001). The observation that dietary richness is associated with a decrease in FCE is consistent with earlier reports (Tsaras et al., 1998; Whittemore et al., 2001).
When the bulk content of the feed increases beyond the threshold values that mark the breaking point, the amount of feed consumed decreased. Since the ability to ferment DF increases as the pig grows, it is necessary to determine the influence of the physicochemical properties of the feed on the intestinal capacity of fattening pigs. Effect of dietary fiber content on mean retention time in different segments of the digestive tract of growing pigs.
Influence of physicochemical properties of bulky feeds on voluntary feed intake in
Introduction
There is ample evidence that as pigs grow, their ability to utilize fiber-rich feed increases (Bindelle et al., 2008). Therefore, the influence of WHC, ADF, NDF and bulk density in predicting intestinal capacity between weaned and finishing pigs is likely to be different. Dry matter degradability and intestinal development can influence intestinal transit and therefore VFI (Whittemore et al., 2003a).
Materials and Methods
- Description of study site
- Pigs and housing
- Feeds
- Experimental design and management of pigs
- Statistical analyses
The weight of feed consumed for that week was divided by 7 to estimate the ADFI. Care and use of the pigs was carried out in accordance with the ethical needs of the certification of authorization for live animal experiments provided by the UKZN Animal Ethics Committee, reference number 096/11/Animal. In this model, breakpoints were used to estimate the thresholds of feed physicochemical properties at which the extent limited FCE.
Results
- Effects of fibre source, inclusion level and week on scaled feed intake
- Physicochemical properties of fibrous feeds affecting intake, weight gain and feed
Υi is the FCE when the ratio of weight gain to feed intake reaches a maximum value or begins to decrease with continuous increase in bulk content. An increase in bulk density of the fibrous diets caused a linear increase (P < 0.05) in GDT. Using the broken stick regression model, the threshold values of the physicochemical properties indicating the break point of FCE when the ratio of weight gain to feed intake reached its maximum or started to decline occurred when CF was 116 ± 25 g/kg DM.
Discussion
The linear decrease in SFI as WHC increased reflects the physical 'bulk' of the feed exceeding the capacity of the intestine (Cole et al., 1972; Kyriazakis and Emmans, 1995; Whittemore et al., 2003a). However, the levels of the NSPs in the diets used in the current study were not determined. The finding that an increase in the level of CF in the diet caused a decrease in FCE confirms that replacing the conventional feed components with the fibrous ingredients reduced the digestible portion of the diet that could be used to promote potential growth (Nyachoti et al., 2004).
Conclusions
Intrinsic ability of the faecal microbial flora to ferment dietary fiber at different growth stages in pigs. Increased viscosity of the intestinal contents changes the structure of the small intestine and intestinal growth, stimulates the spread of enterotoxigenic Escherichia coli in newly weaned pigs. Effects of different sources and levels of dietary fiber in diets on performance, digestibility and antibiotic treatment of post-weaning pigs.
General discussion, conclusions and recommendations
General discussion
The objective of Chapter 4 was to determine the physicochemical properties of a feed that best describe feed mass so that the gut capacity of reduced pigs can be predicted. The selection criterion was based on the change in chemical composition and the range in their physicochemical volume measurements. Alternatively, intake for low-CP diets was inhibited, suggesting that other physicochemical properties of the food limited intake.
Conclusions
During finishing, the reduced SFI as size increased could be attributed to the development of the intestinal organs of fattening pigs, in particular the enlargement of the large intestine and caeca, which influences the behavior of the physicochemical properties of the feed during the influence intestinal transit in a different way than in weaned pigs. pigs. The decrease in volumetric capacity in fattening pigs strongly suggests a relationship between the size of the intestinal organs and body weight.
Recommendations and further research
