The physiological stage of pigs may influence total tract digestibility of nutrients because the digestibility of energy and some nutrients increases as body weight increases, but the impact of physiological stage may be greater for high-fiber diets than for diets with less concentration of fiber. Full fat rice bran (FFRB) and defatted rice bran (DFRB) are produced in the rice milling process and is available for animal feeding. However, because of the high concentration of dietary fiber, FFRB and DFRB may be better suited for diets fed to sows than for diets for weanling or growing pigs, but there is a lack of data on the digestibility of energy and nutrients in FFRB and DFRB fed to sows. Therefore, the objective of this experiment was to test the null-hypothesis that the apparent total tract digestibility (ATTD) of gross energy (GE), dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and P in a corn-soybean meal diet and in diets containing FFRB or DFRB is not different between lactating sows and gestating sows if both groups are allowed to consume their diet on an ad libitum basis.

Spray-dried plasma protein is commonly used in weanling diets due its functional components and high concentration of digestible amino acids. Hydrolyzed spray-dried bovine plasma (H-SDBP) is a new source of spray-dried plasma protein that may be used as a protein source in diets for weanling pigs. There are, however, no data to demonstrate the efficacy of this novel source. Pigs fed diets spray-dried plasma protein have increased growth performance when exposed to a challenge model; therefore, it is possible that H-SDBP improves performance of challenged pigs similarly as other sources of spray-dried plasma protein. Therefore, an experiment was conducted to test the hypothesis that dietary inclusion of H-SDBP is as effective as spray-dried bovine plasma (SDBP) in increasing growth performance of weanling pigs housed in uncleaned pens.

In plant-based feed ingredients there is a considerable amount of P bound to phytate, limiting the amount of P that is available for utilization, but inclusion of microbial phytase in pig diets increases the digestibility of P. The negatively charged phytate molecule can chelate Ca cations resulting in formation of insoluble Ca-phytate complexes. Degradation of phytate by microbial phytase may prevent formation of these non-digestible complexes, resulting in increased Ca digestibility. It is also possible that use of exogenous phytase reduces endogenous loss of Ca. If indeed the reduced endogenous loss of Ca is a result of degradation of phytate, it is expected that increased doses of dietary phytase will linearly reduce endogenous losses of Ca, but this hypothesis has not been experimentally verified. Therefore, this experiment was conducted to test the hypothesis that increasing dietary phytase reduces basal endogenous loss of Ca and increases digestibility of P in growing pigs.

Rapeseed is the second most produced oilseed in the world after soybean, and after the oil is extracted, a protein-rich meal is the resulting byproduct containing greater concentrations of sulfur amino acids (AA; i.e., Met and Cys) and Lys compared with legumes and cereal grains. Rapeseed proteins have great potential as a high-quality plant-based protein for humans due to their well-balanced AA profile, high metabolic utilization of protein, a protein digestibility corrected amino acid score (PDCAAS) similar to soy and milk proteins, and easily separable antinutritional factors. However, to our knowledge, digestible indispensable amino acid score (DIAAS) has not been determined for rapeseed protein isolate and the level of processing required to concentrate rapeseed into a protein isolate warrants further evaluation of its protein quality. Therefore, this experiment was conducted to test the hypothesis that heat treatment of rapeseed protein isolate will increase the digestibility of AA by growing pigs and result in a DIAAS that is comparable to soy and animal protein isolates.

Corn coproducts produced from the fuel ethanol or the wet milling industries may be used in diets for pigs. Different technologies are used to develop high protein corn co-products, but in addition to providing amino acids to the diets, high protein corn co-products also provide energy to the diets. The energy concentrations in corn protein may depend on the concentrations of fat, carbohydrates, and protein in sources of corn protein. Newly developed corn proteins contain 40 to 50% crude protein. There are, however, limited data on how differences in the chemical composition of different sources of corn protein influence the concentrations of digestible energy (DE) and metabolizable energy (ME) when fed to weanling pigs. Therefore, the objective of this experiment was to test the null hypothesis that there is no difference in the apparent total tract digestibility (ATTD) of gross energy (GE) and concentrations of DE and ME among 3 sources of corn protein when fed to weanling pigs.

Corn coproducts produced from the fuel ethanol or the wet milling industries may be used in diets fed to pigs. Newly developed corn proteins are high protein feed ingredients with approximately 40 to 50% crude protein (CP), and corn protein may be a great source of digestible amino acids (AA) in diets fed to weanling pigs. There are, however, limited data on the digestibility of AA in different sources of corn protein fed to weanling pigs. Therefore, the objective of this experiment was to test the null hypothesis that there is no difference in the standardized ileal digestibility (SID) of AA in 3 different sources of corn protein when fed to weanling pigs.

Zinc (Zn) is an essential trace element that is needed for growth, bone development, and immune competence. Inorganic Zn sources such as Zn oxide and Zn sulfate (ZnSO₄) are most commonly used in swine diets. However, because of low bioavailability of Zn the inorganic Zn sources chelated Zn sources may be used instead because these sources have greater bioavailability of Zn. Chelated zinc may also reduce reactiveness with other components of the diet. A new chelated Zn source, zinc bis-glycinate, in which Zn is bound to two glycine molecules, was recently developed, but there is limited information about effects of this new chelated Zn source on digestibility and Zn retention in pigs. Therefore, an experiment was conducted to test the hypothesis that the relative bioavailability by weanling pigs of Zn in Zn bis-glycinate is greater than in Zn mono-glycinate and in ZnSO₄.

The limited capacity for weanling pigs to secret HCl in the stomach may be exacerbated by inclusion of ingredients with high acid binding capacity such as limestone and monocalcium phosphate. As a consequence, reducing the amount of these 2 ingredients in diets for weanling pigs may contribute to a stable low pH for proper pepsin activity and increased action of microbial phytase. Inclusion of high doses of phytase that results in increased phytate degradation and increased release of Ca, P, and inositol may also be beneficial to newly weaned pigs. Therefore, an experiment was conducted to test the hypothesis that lowering dietary Ca and P reduces gastric pH and diarrhea of weanling pigs, but microbial phytase may overcome negative effects of low Ca and P on growth performance and bone ash.

Hybrid rye may replace a portion of barley or wheat in diets for growing and finishing pigs with minimal impact on growth performance or carcass characteristics, but at very high inclusion rates in finishing diets, feed intake may be reduced if hybrid rye replaces wheat. However, limited published data exist for effects of feeding hybrid rye to growing-finishing pigs in place of corn. Therefore, an experiment was conducted to test the hypothesis that average daily gain (ADG) and carcass characteristics will not differ when hybrid rye partially replaces corn in diets for growing-finishing pigs.