Addition of hydrochloric acid to collection bags or collection containers did not change basal endogenous losses or ileal digestibility of amino acid in corn, soybean meal, or wheat middlings fed to growing pigs.

OBJECTIVE: The hypothesis was that apparent ileal digestibility (AID), basal endogenous losses, and standardized ileal digestibility (SID) of amino acids (AA) are not affected by adding acid to collection containers or bags used to collect ileal digesta from pigs. METHODS: Twenty-four growing barrows (initial body weight: 77.8±4.5 kg) that were fitted with a T-cannula in the distal ileum were fed diets for three 7-d periods. An N-free diet and 3 diets containing corn, soybean meal, or wheat middlings as the sole source of AA were used. Within each period, each of the 4 diets were fed to 6 pigs. Among the 6 pigs, digesta from 3 pigs were collected in bags containing no HCl, whereas 40 mL of 3 N HCl was included in the bags used to collect digesta from the remaining 3 pigs. Every other bag collected from each pig was emptied into a container without adding HCl, whereas the remaining bags were added to a container along with 40 mL of 3 N HCl for each bag. All digesta were stored at -20°C immediately after collection. Data were analyzed using a model that included feed ingredient, HCl in bags, HCl in containers, and all 2-way and 3-way interactions as fixed effects. No 3-way interactions were significant, and data were, therefore, reanalyzed independently for each diet as a 2×2 factorial. RESULTS: There were no interactions between adding HCl to collection bags and to containers, and no effects of adding HCl to collection bags or containers for AID, basal endogenous losses, or SID of most AA were observed. CONCLUSION: It is not necessary to add acid to digesta collection bags or collection containers if ileal digesta are stored at -20°C immediately after collection.

Technical note: concentrations of soluble, insoluble, and total dietary fiber in feed ingredients determined using Method AOAC 991.43 are not different from values determined using Method AOAC 2011.43 with the AnkomTDF Dietary Fiber Analyzer.

The primary objective of this experiment was to test the hypothesis that concentrations of soluble (SDF), insoluble (IDF), and total dietary fiber (TDF) in feed ingredients used in diets for pigs and poultry analyzed using Method AOAC 2011.25 are greater than values determined using Method AOAC 991.43. A second objective was to determine the variation that may exist among 3 laboratories using the 2 methods with the AnkomTDF Dietary Fiber Analyzer (Ankom Technology, Macedon, NY). The 3 laboratories were the Ministry of Agriculture Feed Industry Center (MAFIC) at China Agricultural University, Trouw Nutrition, and Hans H. Stein Monogastric Nutrition Laboratory at University of Illinois at Urbana-Champaign (UIUC). All laboratories analyzed SDF and IDF in feed ingredients in duplicate or triplicate using both methods AOAC 991.43 and 2011.25 with the AnkomTDF Dietary Fiber Analyzer. The 9 test ingredients were wheat, soybean meal, rapeseed meal, sugar beet pulp, peas, horse beans, native pea starch, and 2 samples of corn; 1 from Europe and 1 from China. All ingredient samples, with the exception of Chinese corn, were procured by Trouw Nutrition, ground to pass through a 0.5 mm screen, subsampled, and sent to MAFIC and UIUC. Data were analyzed using SDF, IDF, and TDF as response variables, replication as random effect, and method and location as fixed effects over all ingredients and within each ingredient. When averaged among 9 different ingredients, results indicated that SDF, IDF, and TDF values were not different with either method or at any laboratory. However, the concentration of IDF in corn, wheat, peas, and sugar beet pulp determined using Method AOAC 991.43 was greater (P < 0.05) compared with 2011.25. Soluble dietary fiber determined using Method AOAC 2011.25 was greater (P < 0.05) in corn, rapeseed meal, soybean meal, and sugar beet pulp compared with 991.43. There was no difference in TDF determined with either method, except for wheat having greater (P < 0.05) TDF when determined using Method AOAC 991.43. Interlaboratory variation for SDF, IDF, and TDF was 0.38, 0.87, 1.20, respectively, with Method AOAC 991.43 and 0.40, 0.93, and 1.27, respectively, with 2011.25. Therefore, values determined with the AnkomTDF Analyzer are repeatable among laboratories and can be used in feed formulation worldwide. In conclusion, it is recommended that Method AOAC 991.43 be used to determine SDF, IDF, and TDF in feed ingredients and diets for pigs and poultry.

Structures and characteristics of carbohydrates in diets fed to pigs: a review.

The current paper reviews the content and variation of fiber fractions in feed ingredients commonly used in swine diets. Carbohydrates serve as the main source of energy in diets fed to pigs. Carbohydrates may be classified according to their degree of polymerization: monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Digestible carbohydrates include sugars, digestible starch, and glycogen that may be digested by enzymes secreted in the gastrointestinal tract of the pig. Non-digestible carbohydrates, also known as fiber, may be fermented by microbial populations along the gastrointestinal tract to synthesize short-chain fatty acids that may be absorbed and metabolized by the pig. These non-digestible carbohydrates include two disaccharides, oligosaccharides, resistant starch, and non-starch polysaccharides. The concentration and structure of non-digestible carbohydrates in diets fed to pigs depend on the type of feed ingredients that are included in the mixed diet. Cellulose, arabinoxylans, and mixed linked ß-(1,3) (1,4)-d-glucans are the main cell wall polysaccharides in cereal grains, but vary in proportion and structure depending on the grain and tissue within the grain. Cell walls of oilseeds, oilseed meals, and pulse crops contain cellulose, pectic polysaccharides, lignin, and xyloglucans. Pulse crops and legumes also contain significant quantities of galacto-oligosaccharides including raffinose, stachyose, and verbascose. Overall, understanding the structure, characteristics and measurable chemical properties of fiber in feed ingredients may result in more accurate diet formulations, resulting in an improvement in the utilization of energy from less expensive high-fiber ingredients and a reduction in reliance on energy from more costly cereal grains.

Non-antibiotic feed additives in diets for pigs: A review.

A number of feed additives are marketed to assist in boosting the pigs' immune system, regulate gut microbiota, and reduce negative impacts of weaning and other environmental challenges. The most commonly used feed additives include acidifiers, zinc and copper, prebiotics, direct-fed microbials, yeast products, nucleotides, and plant extracts. Inclusion of pharmacological levels of zinc and copper, certain acidifiers, and several plant extracts have been reported to result in improved pig performance or improved immune function of pigs. It is also possible that use of prebiotics, direct-fed microbials, yeast, and nucleotides may have positive impacts on pig performance, but results have been less consistent and there is a need for more research in this area.

Effects of physicochemical characteristics of feed ingredients on the apparent total tract digestibility of energy, DM, and nutrients by growing pigs.

Effects of physicochemical characteristics of feed ingredients on DE and ME and apparent total tract digestibility (ATTD) of GE, DM, and nutrients were determined in growing pigs using ingredients with different ratios between insoluble dietary fiber (IDF) and soluble dietary fiber (SDF). Eighty growing barrows (BW: 48.41 ± 1.50 kg) were allotted to a randomized complete block design with 10 diets and eight replicate pigs per diet. Dietary treatments included a corn-based diet, a wheat-based diet, a corn-soybean meal (SBM) diet, and seven diets based on a mixture of the corn-SBM diet and canola meal, distillers dried grains with solubles (DDGS), corn germ meal (CGM), copra expellers, sugar beet pulp (SBP), synthetic cellulose, or pectin. Values for the ATTD of DM and nutrients were also compared with the in vitro digestibility of GE, DM, and nutrients. Results indicated that the ATTD of GE was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, and synthetic cellulose, but not different from corn, SBM, or pectin. SBM had greater (P < 0.05) DE and ME (DM basis) compared with all other ingredients. The concentration of ME (DM basis) was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, synthetic cellulose, and pectin, but not different from corn. Stronger correlations between total dietary fiber (TDF) and DE and ME than between ADF or NDF and DE and ME were observed, indicating that TDF can be used to more accurately predict DE and ME than values for NDF or ADF. The DE, ME, and the ATTD of DM in ingredients were positively correlated (P < 0.05) with in vitro ATTD of DM, indicating that the in vitro procedure may be used to estimate DE and ME in feed ingredients. Swelling and water-binding capacity were positively correlated (P < 0.05) with the ATTD of IDF, TDF, nonstarch polysaccharides (NSP), and insoluble NSP, and viscosity was positively correlated (P < 0.05) with the ATTD of NDF, IDF, and insoluble NSP, indicating that some physical characteristics may influence digestibility of fiber. However, physical characteristics of feed ingredients were not correlated with the concentration of DE and ME, which indicates that these parameters do not influence in vivo energy digestibility in feed ingredients. It is concluded that the DE and ME in feed ingredients may be predicted from some chemical constituents and from in vitro digestibility of DM, but not from physical characteristics.