Factors Affecting Amino Acid Digestibility in Monogastric Animals
Abstract
The objective of the experiments conducted for this dissertation was to determine the standardized ileal digestibility (SID) of amino acids (AA) in a variety of feed ingredients for broiler chickens and pigs. The effects of casein in experimental diets on the SID of AA in corn distillers’ dried grains with solubles (DDGS) fed to pigs were evaluated. The SID of AA in feed ingredients, which include full-fat soybean (FFSB), two soybean meals (SBM), peanut flour (PNF), full-fat canola seeds (FFCS), canola meal (CM), canola expellers (CE), hydrolyzed feather meal (HFM), flash dried poultry protein (FDPP), poultry meal (PM), and meat and bone meal (MBM), were compared in broiler chickens and pigs. One of the studies determined the ileal digestibility of AA in casein by regression analysis and investigated the effects of 60 g/kg casein in experimental diets on the SID of AA in DDGS. The ileal digestibility of AA in casein were close to 100%, ranging from 95.5% (SE = 9.10) for Cys to 103.1% (SE = 4.40) for Arg. In addition, the SID of Lys and Phe in DDGS determined by pigs fed the diet containing DDGS and casein were greater (P < 0.05) than the values determined by pigs fed the diet containing DDGS without casein. Based on the results of this experiment, two additional experiments were conducted to determine the effects of graded concentrations of casein from 55 to 165 g/kg in experimental diets on the SID of AA in DDGS and to determine the effects of dietary DDGS concentrations (i.e., 155.6 or 466.8 g/kg) and addition of casein in experimental diets on the SID of AA in DDGS. The SID of indispensable AA, except for Arg and Lys, linearly decreased (P < 0.05) as the concentration of casein in experimental diets increased. Moreover, pigs fed the diets containing 155.6 g/kg DDGS had less (P < 0.05) SID of indispensable AA, except for Trp, in DDGS than those fed the diets containing 466.8 g/kg DDGS regardless of the addition of casein in experimental diets. Therefore, it may be concluded that the addition of casein improves the SID of AA in DDGS, but reduced DDGS concentration in experimental diets decreases the SID of AA in DDGS. In one pair of experiments conducted to compare the SID of AA in FFSB, SBM containing 430 g/kg crude protein, SBM containing 470 g/kg crude protein, and PNF between broiler chickens and pigs, the SID of AA, except for Trp, Ala, and Glu, in test ingredients for pigs were greater (P < 0.05) than the values for broiler chickens. In addition, in both broiler chickens and pigs, the SID of Ile, Leu, and Val in FFSB were less (P < 0.05) than in the other test ingredients. In another pair of experiments conducted to compare the SID of AA in FFCS, CM, and CE between broiler chickens and pigs, interactions (P < 0.05) between experimental diets and species were observed in the SID of AA, except for Lys, Gly, Pro, and Ser.
Degree
Ph.D.
Advisors
Adeola, Purdue University.
Subject Area
Analytical chemistry|Physiology|Agronomy|Animal sciences|Chemistry|Morphology
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