Research Reports

Negative effects of distillers dried grains with solubles (DDGS) on fat quality of pigs are not ameliorated by addition of corn germ, tallow, palm kernel oil, or glycerol to finishing diets

Distillers dried grains with solubles (DDGS) can be fed in swine diets at an inclusion rate of up to 30% without negatively affecting pig growth performance. However, DDGS contains high levels of polyunsaturated fatty acids (PUFA), which may promote deposition of unsaturated dietary fatty acids in adipose tissue. Consequently, inclusion of DDGS at more than 20% has been shown to result in increased fat iodine values (IV) and soft belly production.  The disadvantages of this decrease in fat quality include reduced shelf life, increased susceptibility to oxidative damage, and reduced belly sliceability.

An experiment was performed to determine if the addition of different sources of saturated fat would improve belly fat quality in pigs fed a DDGS-based diet. In addition, the hypothesis that the iodine value product (IVP) of the diet can be used to predict backfat IV and belly fat IV of pigs fed diets containing DDGS was tested.

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Effects of graded levels of microbial phytase on the standardized total tract digestibility of phosphorus in corn and corn co-products

Corn contains approximately 0.26% phosphorus, but most of this phosphorus is bound to phytic acid, or phytate, and thus is not bioavailable to pigs because they lack the enzyme phytase. Corn-based diets can be supplemented with inorganic phosphorus to help meet pigs' phosphorus needs; however, rising costs of inorganic phosphorus makes this approach increasingly uneconomical. Helping pigs digest more of the phosphorus that naturally occurs in the diet could provide a cost-effective alternative to inorganic phosphorus supplementation while also helping to reduce the environmental burden of excreted phosphorus. An experiment was conducted to determine how adding graded levels of microbial phytase affected the standardized total tract digestibility (STTD) of phosphorus in corn and corn co-products. From these data, regression equations were developed to predict the response to adding different levels of phytase to each ingredient.

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Amino acid digestibility and concentration of digestible and metabolizable energy in a threonine co-product fed to weanling pigs

Because weanling pigs cannot properly digest soybean meal, animal proteins such as fish meal and spray-dried plasma protein are often used in starter diets. However, the cost of these ingredients has become prohibitive for many swine producers, and new sources of digestible protein for weanling pigs are being sought.

Researchers at the Stein Monogastric Nutrition Lab have been studying a co-product of the production of synthetic L-Threonine, which is used as a supplement in low-protein diets. Synthetic L-Threonine is produced by fermenting a carbohydrate substrate using  bacteria such as E. coli. Threonine is extracted from the fermentation broth. The leftover biomass and substrate have the potential to be used as a feed source, but little is known about its nutritional value. Two experiments were conducted to measure amino acid digestibility and energy concentration in a threonine co-product that is produced by drying this left-over biomass.

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Amino acid digestibility and energy concentration of copra expellers, palm kernel expellers, and palm kernel meal fed to growing pigs

Copra and palm kernel co-products are commonly fed to ruminant animals in some parts of the world. However, very limited research has been reported on the use of these ingredients in swine diets. No values are listed in the NRC (1998) for copra expellers, palm kernel expellers, or palm kernel meal.

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Digestibility of phosphorus by weanling pigs of fermented and conventional soybean meal without and with exogenous phytase

The majority of phosphorus in conventional soybean meal is bound in the phytate complex. Pigs do not secrete the phytase enzyme, so phytate-bound phosphorus is not digested and is excreted in the feces. Not only does this deprive pigs of an essential nutrient, but excessive phosphorus excretion can contribute to environmental problems as well.

Addition of microbial phytase is one strategy for increasing the digestibility of phosphorus in soybean meal. Another potentially effective strategy is to feed fermented soybean meal.  Fermentation may result in hydrolysis of phytate and release of phytate-bound phosphorus, thus making more phosphorus available to the pig.

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Digestibility of amino acids in corn, corn co-products, and bakery meal fed to growing pigs

Rising costs of traditional swine feeds are causing many producers to look for alternative feedstuffs to deliver nutritional value at a lower cost. The corn milling and fermentation industries, and the human food industry, create co-products which can be fed to livestock.  One of these, distillers dried grains with solubles (DDGS), has been found to be suitable for inclusion in swine diets up to 30%. Other co-products have not been as extensively studied. This experiment was performed to measure the apparent (AID) and standardized (SID) ileal digestibility of crude protein and amino acids in corn gluten meal, corn gluten feed, corn germ meal, hominy feed, and bakery meal in growing pigs and to compare these values to the values observed for DDGS and corn.

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Amino acid digestibility in canola-, cotton- and sunflower-products fed to finishing pigs

Soybean meal is a high quality source of protein for swine diets. Due to the growth in global production of pigs and poultry, demand for soybeans is increasing rapidly, outpacing production. Therefore, other sources of plant protein are being sought to lower feed costs.

The most abundant oilseeds produced in the world, aside from soybeans, are cottonseed, canola seed (rapeseed), and sunflower seed. These may be fed as de-oiled meals, or the full fat seeds can be fed to increase the energy concentration of the diet.

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Effect of the form of dietary fat and the concentration of dietary fiber on digestibility of fat by growing pigs

To determine true digestibility of nutrients, endogenous losses from the digestive tract must be measured. Because consistent values for endogenous losses of fat (ELF) in pigs have yet to be determined, the calculation of fat digestibility has mostly been limited to apparent digestibility.

Endogenous losses of fat may be influenced by the form of fat – extracted or intact – and by the concentration of fiber in the diet. The objective of this experiment was to determine the effect of the form of dietary fat on ileal and total tract digestibility of fat in growing pigs. To do so, it was necessary to measure endogenous losses of fat and to correct for the difference in amounts of dietary fiber in diets containing extracted fat and diets containing intact fat.

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Standardized total tract digestibility of phosphorus in blood products fed to weanling pigs

Blood meal and spray dried plasma protein are often included in diets fed to weanling pigs, and blood products are considered excellent sources of protein. The objective of this research was to measure apparent total tract digestibility (ATTD) and standardized total tract digestibililty (STTD) of phosphorus in spray dried animal plasma, porcine blood meal, and avian blood meal fed to weanling pigs. References such as the NRC typically provide relative bioavailability values for phosphorus rather than digestibility values. Relative bioavailability values, however, depend on the standard (e.g., monosodium phosphate or dicalcium phosphate) to which the availability is compared. Thus, these values are believed not to be additive in mixed diets. It is believed that STTD values are additive in mixed diets, and therefore will enable producers to formulate diets that accurately meet the phosphorus requirement of pigs without creating unneccesary excesses that are excreted in the manure.

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Amino acid digestibility in blood meal fed to weanling pigs

Dried blood meal is commonly used as a high-quality protein source in nursery pig diets. Growth studies have indicated that blood meal can be a better protein source than dried skim milk, fish meal, and soy protein concentrate.  However, the growth effects of blood meal vary across studies; this may be due to differences in protein quality.

Limited data exist on digestibility of crude protein and amino acids in blood meal produced from different species and with different drying methods.  Therefore, an experiment was conducted to measure apparent (AID) and standardized (SID) ileal digestibility of crude protein and amino acids in two sources of blood meal.

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Digestibility of dietary fiber in distillers coproducts fed to growing pigs

Fiber digestibility is one factor in the efficiency of energy utilization in fibrous feed ingredients. Fiber can be digested via fermentation in the ileum or in the hindgut.

Fecal matter and ileal digesta from pigs fed one of 29 different diets were analyzed to measure the apparent ileal digestibility (AID) and the apparent total tract digestibility (ATTD) of dietary fiber in different sources of distillers dried grains with solubles (DDGS) and to calculate hindgut fermentation (HGF) of dietary fiber in DDGS fed to growing pigs.

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Digestibility of amino acids in novel soybean products

Raw soybeans contain antinutritional factors such as trypsin inhibitors (TI) and lectins.  The production of soybean meal involves a heating step, which reduces these anti-nutritional factors. However, conventional soybean meal contains compounds which can cause digestive disturbances in weanling pigs. Soybean meal is therefore limited in pig starter diets. Other protein sources, such as fish meal, casein, and soy protein isolate, are used for young pigs.

Two new soybean products were recently introduced to the U.S. feed market.  Fermented soybean meal (FSBM) and enzyme-treated soybean meal (ESBM) are believed to have a lower concentration of antinutritional factors and a higher concentration of crude protein and amino acids than conventional soybean meal.  They are also believed to be better tolerated by young pigs. However, not much is known about the digestibility of the protein in these two products.

This experiment was conducted to compare the digestibility of amino acids in weanling pigs of FSBM, ESBM, conventional de-hulled soybean meal, fish meal, casein, and soy protein isolate.

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Evaluation of growth performance and carcass characteristics in pigs fed two varieties of genetically modified corn

Most corn hybrids grown in the US are genetically modified to resist certain pests or to tolerate certain herbicides. Numerous studies have been conducted to determine the nutritional value of corn that is genetically modified for pest resistance, but there are no published reports about feeding corn that has been modified for both pest resistance and insecticide tolerance to pigs. Investigation into the nutritional value of such corn is, however, warranted, because the use of crops with multiply stacked traits is rapidly increasing; approximately 35 million acres of crops with double- and triple-stacked traits were planted in the United States in 2006.

Two experiments were, therefore, conducted to determine if the nutritional value of corn grain with multiple genetically modified traits is different from that of nontransgenic corn. The hypothesis in both experiments was that pigs fed transgenic corn would not differ in growth performance or carcass characteristics from pigs fed nontransgenic corn.

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A novel source of high-protein distillers dried grains

Buhler, Inc. of Minneapolis, Minnesota has developed a new fractionation process to more efficiently produce ethanol from corn. In this process, the germ is removed from the corn grain and the degermed grain is passed through roller mills and aspirators to remove the bran. The endosperm is fermented to produce ethanol, and the rest of the grain is left as a co-product, referred to here as HP-DDGBuhler.

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Digestibility of amino acids in corn and corn co-products fed to growing pigs

The objective of this experiment was to measure the standardized ileal digestibility of crude protein and amino acids in hominy feed, corn gluten meal, corn gluten feed, and corn germ meal and to compare these values to the digestibility of crude protein and amino acids amino acids in corn and distillers dried grains with solubles (DDGS). Results showed that the digestibility of most amino acids were greater (P < 0.05) in hominy feed and in corn gluten meal than in the other ingredients, whereas the digestibility of most amino acids in corn gluten feed was lower (P < 0.05) than in the other ingredients.

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