Browsing by Author "Song, Ran"

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    Growth performance, carcass characteristics, physiological and gut health effects of feeding diets containing bacitracin methylene disalicylate (BMD) to heat-stressed finishing pigs.
    (2009-12) Song, Ran
    Heat stress affects pig growth performance, carcass composition, and immune status. The present study was conducted to evaluate the effects of heat stress and adding bacitracin methylene disalicylate (BMD, 30g/ton) to a 10% DDGS commercial diet on growth performance, carcass characteristics, physiological parameters, small intestine morphology, and hindgut volatile fatty acid (VFA) production of finishing pigs. Four groups of 32 finishing pigs (n = 128) with initial BW between 80 to 90 kg were used in this study. Pigs were randomly assigned to diets and environmental temperature treatments in a 2 x 2 factorial arrangement. Pigs were fed a control (CON) or BMD (30g/ton) diet and exposed to a constant thermal neutral temperature (23°C) or cyclical heat stress conditions (37°C from 10:00 to 19:00 and 27°C from 19:00 to 10:00) in environmental chambers for a 28-d experimental period. Pigs housed under heat stress conditions had significantly lower average daily gain (ADG, P < 0.0001), average daily feed intake (ADFI, P < 0.0001), gain:feed (G:F, P < 0.001), and higher average daily water intake (ADWI, P = 0.03), compared with pigs housed in the thermoneutral environment. Supplementation of BMD in the diet did not improve growth performance of pigs. Average daily gain tended (P = 0.07) to be lower for pigs fed the BMD diet, while ADFI, G:F, and ADWI were not affected by dietary treatment. Carcass characteristics did not differ between dietary treatments. However, pigs assigned to the heat stress environment had lower live BW (P < 0.0001) and lower hot carcass weight (P < 0.0001) than pigs housed in the thermal neutral environment. Dressing %, 10th rib back fat depth, loin eye area, and lean % were not affected by temperature treatment. Saliva cortisol concentration did not differ between dietary treatments during the experimental period, but the initial level was lower (P < 0.05) for pigs fed the BMD diet. Heat stress led to an increased (P < 0.05) level of saliva cortisol on d 1, but no effects were observed on the following days. Serum haptoglobin concentration was not different between dietary treatments, while heat stressed pigs showed a higher (P < 0.05) level of haptoglobin on d 1, and levels tended to remain higher (P < 0.1) on d 13 of heat stress. Cytokines IL-1β and TNF-α were not affected by heat stress, but pigs fed the BMD diet had an initial lower (P < 0.0001) level of serum IL-1β, and tended to be lower (P < 0.1) on d 13 of heat stress as compared to pigs fed CON. Small intestine morphology was not affected by temperature treatment, but pigs fed the BMD diet tended to have greater (P = 0.07) villi height at duodenum, and greater crypt depth at duodenum (P = 0.09) and jejunum (P = 0.07), respectively. Dietary treatment did not affect VFA production in the cecum, while pigs housed under heat stress conditions tended to have less propionate (P = 0.08) concentration, greater A:P ratio (P = 0.08), and significantly less valerate (P = 0.02) produced in the cecum compared with pigs under the thermoneutral environment.
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    How Do We Evaluate Peroxidation of Feed Fats?
    (University of Minnesota. Minnesota Extension Service, 2012-09) Shurson, Jerry; Liu, Pai; Song, Ran; Kerr, Brian
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    Lipid peroxidation in corn dried distillers grains with solubles (DDGS) and effects of feeding a highly oxidized DDGS source to swine
    (2013-01) Song, Ran
    Within the past decade, the United States has experienced a rapid growth in corn ethanol production. With every gallon of ethanol produced, approximately 2.6 kg of distillers grains are produced. In 2011, the United States ethanol industry produced 35.7 million metric tons of distillers grains for use in livestock and poultry feeds, among which approximately 3.9 million metric tons of dried distillers grains with solubles (DDGS) were used as a feed ingredient in pork production. Due to the cost competitiveness of DDGS relative to the recent high prices for corn and soybean meal, pork producers have saved between $3 to 9 per market hog by adding up to 40% DDGS to grower-finisher diets. However, the long-term sustainability of this level of usage, and the potential to further increase DDGS usage in grower-finisher swine diets is in jeopardy. Concerns about the potential negative impact of oxidized corn oil in DDGS on health and antioxidant status of pigs, and the impact of feeding high concentrations PUFA present in DDGS lipid on pork fat quality may limit the use of high levels (20 to 30%) of DDGS in swine diets. Corn DDGS contains approximately 10% corn oil. Corn oil contains high levels of polyunsaturated fatty acids (particularly linoleic acid) that are vulnerable to lipid peroxidation. Drying temperatures used by ethanol plants can vary substantially, and increased drying time and temperature used during the drying process also accelerate lipid peroxidation. Lipid peroxidation, also called lipid oxidation, refers to the oxidative degradation of lipids. Lipid peroxidation proceeds by a sequential free radical chain-reaction mechanism that involves the production of a series toxic secondary lipid peroxidation product. The occurrence of lipid peroxidation in foods or feed ingredients leads to quality and nutritional losses, while it can also take place in vivo leading to several negative effects, including damage of cellular and subcellular bio-membranes, growth depression of animals, and undesirable meat and fat quality. Oxidative damage in feedstuffs reduces feeding values of the ingredients. Lipid peroxidation in animal feed has been shown to negatively affect pig health and growth performance, resulting in more days on feed to reach market weight. Furthermore, changes in body composition, pork quality, and shelf-life stability of fresh and ground pork may occur, leading to a decrease in overall acceptance of pork from animals fed under these dietary conditions. Vitamin E, supplemented in diets, can be deposited in fat associated with muscle tissue as alpha-tocopherol. Vitamin E is the most important natural antioxidant to protect against lipid peroxidation and increase pork shelf-life stability. Feeding DDGS containing oxidized lipids to pigs may require supplementation of higher levels of antioxidants (e.g. vitamin E) than currently being fed. For example, supplementation of additional antioxidants improved growth performance in pigs fed diets containing 20% DDGS or 5% oxidized corn oil. Therefore, the objectives of the following experiments were to evaluate the effects of feeding DDGS containing oxidized lipids on growth performance, metabolic oxidation status, nutrient digestibility, carcass characteristics, pork fat composition, and loin peroxidation status, as well as to determine if any negative effects could be overcome by increasing the dietary level of vitamin E (alpha-tocopheryl acetate).