In poultry, the particle size of inorganic calcium sources has been shown to affect calcium retention and eggshell quality. However, little is known about the effect of particle size of inorganic calcium fed to pigs. Results of a previous experiment conducted in the Stein Monogastric Nutrition Lab indicated that calcium digestibility and retention were not affected by the particle size of supplemental calcium carbonate. A follow-up study was conducted to test the hypothesis that calcium carbonate particle does not affect growth performance by weanling pigs.

Soybeans grown in the northern United States are exposed to fewer growing days and hours of sunlight than soybeans grown elsewhere in the U.S. As a result, soybeans grown in the northern U.S. fix less nitrogen, and have a lower concentration of crude protein, than other U.S. soybeans. However, the concentrations of particular amino acids, particularly indispensable amino acids, are more important for the purposes of diet formulation than the concentration of crude protein. The concentration of amino acids in soybeans grown in different parts of the U.S. has not been determined.

The amount of amino acids in soybean meal that are available to the pig also depends on digestibility, but no research has been conducted to compare the digestibility of amino acids among soybean meal produced in different regions of the U.S. Therefore, an experiment was conducted to compare the standardized ileal digestibility (SID) of amino acids and the concentration of SID amino acids in soybean meal produced in different regions within the United States and fed to growing pigs.

The nutritional value of soybean meal from different sources may vary due to differences in processing techniques and environmental conditions such as growing areas, soil type, and variety of soybeans. The Philippines import soybean for livestock feed from many different countries. However, the nutritional quality of soybean meal from these different origins has not been compared. It is important for producers formulating diets in the Philippines to know whether the same values can be used in formulations for all sources of imported soybean meal. Therefore, two experiments were conducted to determine the concentrations of apparent metabolizable energy (AME) and nitrogen-corrected apparent metabolizable energy (AMEn), and the standardized ileal digestibility (SID) of amino acids by broilers fed soybean meal from Argentina, Brazil, China, Thailand, and the United States.

Several co-products from rice processing can be used as animal feed. Brown rice is the whole rice grain that is left after the hull layer has been removed, leaving the germ, starchy endosperm, and bran. Rice bran is the outer brown layer of brown rice, which is removed to produce white rice. It is high in fiber, and also contains about 15% crude protein and 14 to 20% fat. Rice bran can be fed as full fat rice bran or defatted rice bran. Broken rice, or brewer's rice, consists of white rice grains that have been damaged in processing. It is high in starch and contains little fat, fiber, or protein (Table 1).

Non–starch polysaccharides (NSPs), primarily arabinoxylan and cellulose, comprise 20 to 25% of defatted rice bran. NSPs reduce nutrient absorption and energy digestibility. Addition of exogenous xylanase to wheat co-products, which also have high concentration of NSPs, may improve digestibility of energy, but there is limited information about the effects of adding exogenous xylanases to rice co-products. Therefore, an experiment was conducted to determine the effect on concentrations of digestible energy (DE) and metabolizable energy (ME) of adding exogenous xylanase to diets containing full fat rice bran (FFRB), defatted rice bran (DFRB), brown rice, or broken rice.

Particle size is an important consideration for some feed ingredients in pig diets. Reducing the particle size of cereal grains and soybean meal in diets fed to pigs improves digestibility of energy, amino acids, and other nutrients, because feed ground to smaller particle sizes has more surface area on which digestive enzymes can work.

The particle size of inorganic calcium sources has been shown to affect calcium retention in poultry. Particle sizes of 1.00 mm or greater are recommended to optimize calcium retention and eggshell quality in laying hens, but coarse particle sizes result in reduced calcium retention in broiler chicks.  However, little is known about the effect of particle size of calcium sources fed to pigs. Therefore, an experiment was conducted to test different particle sizes of calcium carbonate and determine which size optimizes calcium digestibility and retention by growing pigs.

After corn and wheat, rice is the third most widely grown cereal grain worldwide. Most rice is processed to produce polished white rice for human consumption, and several co-products result from this processing. First, the outer husk, or hull, of the grain is removed. The dehulled grain, consisting of the bran, germ, and endosperm, is brown rice. To produce white rice, the brown rice is milled further and the bran is removed. Rice bran is high in fiber, and also contains about 15% crude protein and 14 to 20% fat. Rice bran can be fed as full fat rice bran or defatted rice bran. Rice bran is sometimes combined with rice hulls to produce rice mill feed. During milling of the rice, some kernels may get broken and cannot be used for human consumption. These broken kernels are known as broken rice or brewers rice and may also be used in animal feeding.

The phosphorus content of rice is similar to that of corn. Most of the phosphorus in rice is in the bran fraction, and 80-85% of the phosphorus in rice bran is bound to phytate, which limits its digestibility by pigs. Microbial phytase can be used in swine diets to increase the digestibility of phytate-bound phosphorus. However, limited information exists about phosphorus digestibility in rice co-products and how it is affected by microbial phytase. Therefore, an experiment was conducted to determine the apparent (ATTD) and standardized (STTD) total tract digestibility of phosphorus in brown rice, broken rice, full fat rice bran (FFRB), defatted rice bran (DFRB), and rice mill feed fed to growing pigs. A second objective of the experiment was to determine the effect of microbial phytase on phosphorus digestibility in rice co-products.

Distillers dried grains with solubles (DDGS) is a co-product of the ethanol industry and is often used as an economical source of energy and protein in swine diets. Conventional DDGS contains approximately 27% crude protein, 10% fat, 9% acid detergent fiber (ADF), and 25% (NDF). The concentrations of digestible energy (DE) and metabolizable energy (ME) in conventional sources of DDGS are approximately 3,500 and 3,350 kcal/kg, respectively. However, there is significant variation in the way different plants produce DDGS. For example, in recent years ethanol plants have begun extracting oil from DDGS to sell to the biodiesel industry. This results in DDGS with its fat content reduced to approximately 6 to 9%, which may result in lower concentrations of DE and ME.

If pigs are fed diets containing decreased levels of DE and ME relative to conventional DDGS, a reduction in growth performance may result. This would make DDGS a less economical feedstuff. An experiment was conducted to determine the variability of DE and ME in DDGS produced in and around Illinois.

When evaluating the energy content of pig diets, producers and feed companies in the United States usually use the digestible energy (DE) and metabolizable energy (ME) systems. However, these systems do not take into account the heat produced by the animals during digestion, and thus the energy lost by pigs in the process of digesting and metabolizing the feed. Pigs fed diets high in fiber have greater feed intake, larger gastrointestinal tracts, and increased hindgut fermentation relative to pigs fed diets containing less fiber. Therefore, they might be expected to have greater heat production as well. As a result, the DE and ME systems may overestimate the energy value of fibrous feed ingredients. Net energy (NE) takes heat production into account, and thus may be a more accurate estimate of the energy available to the pig.

An experiment was conducted to test the hypothesis that increasing dietary fiber in diets fed to growing pigs will increase heat production and decrease net energy values.

Lysine is the first limiting amino acid in swine diets based on corn and soybean meal. Lysine requirements for pigs are affected by growth rate and lean deposition rate, which in turn are affected by sex, genetics, age, and other factors. An experiment was conducted to determine the requirement for standardized ileal digestible (SID) lysine in 25 to 50 kg growing gilts.