Amino acid composition and digestible amino acid content in animal protein by-product meals fed to growing pigs

Authors: Kerr, Brian; URRIOLA, PEDRO - University Of Minnesota; JHA, RAJESH - University Of Hawaii; THOMSON, JOHN - Evonik Degussa Gmbh; CURRY, SHELBY - Oak Ridge Institute For Science And Education (ORISE); SHURSON, GERALD - University Of Minnesota

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2019
Publication Date: 11/5/2019
Citation: Kerr, B.J., Urriola, P.E., Jha, R., Thomson, J.E., Curry, S.M., Shurson, G.C. 2019. Amino acid composition and digestible amino acid content in animal protein by-product meals fed to growing pigs. Journal of Animal Science. 97:4540-4547. https://doi.org/10.1093/jas/skz294.
DOI: https://doi.org/10.1093/jas/skz294

Interpretive Summary: Rendering is a process of grinding, heating, partial separation of fat, and drying of a wide array of inedible animal and carcass tissues, including blood, feathers, muscle, bones, fat, and offal, with the US rendering industry processing over 22 million tons of raw animal components annually. Of the 4.5 million tons of animal derived protein products produced, about 85% are utilized as animal feed ingredients, and is an essential role that the rendering industry plays for achieving environmental and economic sustainability of animal agriculture. Animal protein by-products are concentrated sources of energy, AA, and minerals, which can be an important feedstuff in swine feed formulations depending upon its price relative to competing ingredients, but additional information is needed on their digestible amino acid concentrations. Consequently, the current study was conducted to determine the ileal amino acid digestibility content of animal protein by-products varying in chemical composition. Data from this experiment indicate that the amino acid digestibility of animal protein by-products varied substantially among the animal protein by-products and sources, and that based on these values, animal protein by-product meals can be a valuable source of amino acids in swine feed formulation. This information is important for nutritionists at universities, feed companies, and pig production facilities for the determination of the digestible amino acid value of commonly used animal protein by-products in feed formulations, and provides a basis from which to assess their economic value.

Technical Abstract: An industry survey and an animal experiment were conducted to evaluate the AA compositional variability and standardized ileal digestibility (SID) of AA of animal protein by-products. Animal protein by-product meals (212) were categorized into eight groupings (blood meal, chicken by-product meal, chicken meal, feather meal, meat and bone meal, meat meal, poultry by-product meal, and poultry meal) and analyzed for total AA. Amino acid analysis among (e.g., Lys in blood meal averaged 9.20% compared to 2.31% for feather meal, DM basis) and within (e.g., Lys range of 1.54% in blood meal and 1.44% in feather meal, DM basis) the by-product classifications varied as expected, but on average the total AA values were similar to that reported in the literature. For the determination of the SID of AA, 15 barrows (average initial and final BW of 31.6 and 78.7 kg, respectively) were fitted with a T-cannula in the distal ileum and allotted to 15 diets over fifteen 7-d periods. Pigs were fed a basal diet based on soybean meal and dehulled-degermed corn, 13 diets containing 17.5% animal protein by-product meal to partially replace a portion of the soybean meal and dehulled-degermed corn in the basal diet, or an N-free diet. Values for the apparent ileal AA digestibility of each diet were determined, adjusted to SID based upon the endogenous AA losses determined by feeding the N-free diet, and the SID of AA in each animal protein by-product meal calculated using the difference procedure. The SID of AA varied among (e.g., SID of Lys averaged 91% in chicken meal but 47% in feather meal) and within (e.g., SID of Lys in three meat and bone meals was 80, 71, and 54%) animal protein by-product meals as expected, and were consistent with the literature. Overall, data provides the total and SID of AA for 13 animal protein by-product meals, including data on their variability, which is critical for their use in feed formulation programs.