|GALLOWAY SR, D|
Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/1995
Publication Date: N/A
Interpretive Summary: Broiler litter is abundant in many parts of the USA and often produced on relatively small farms. Therefore, disposal of the byproduct is frequently problematic. Broiler litter can be utilized as a ruminant feedstuff, with realized value under some dietary conditions being greater than that with application to land as fertilizer. However, nutritional characteristics of broiler litter limit production scenarios in which the bioresource can be used effectively and restrict levels of dietary inclusion. Therefore, objectives of our experiment were to determine effects of mixing different sources and levels of amino acids susceptible to nonenzymatic browning reactions and sugars with broiler litter before deep-stacking for different lengths of time on concentrations of different nitrogen fractions and characteristics of degradation in ruminants. Results of this experiment suggest that potential exists to markedly increase feeding value of soybean meal via increased rumen undegradable protein, and possibly of other feedstuffs high in rumen digestible protein as well, by addition to broiler litter before deep-stacking. Magnitude of change in predicted intestinal digestion of soybean meal protein was relatively steady as soybean meal level was varied. Furthermore, these results do not suggest greater loss of nitrogen during deep-stacking with addition of sources of amino acids such as soybean meal and synthetic amino acids. The nature of modifications of added protein, and associated effects on ruminal digestibility, may vary with length of deep-stacking. Changes implicating elevated ruminal undegradable protein concentration in soybean meal were generally not enhanced by addition of different sugar sources.
Technical Abstract: Different sources and levels of amino acids (soybean meal at 0, 10, 20, or 40% of dry matter; similar quantities of lysine and methionine in synthetic forms) and sugars were mixed with broiler litter and placed in dacron bags embedded in a deep-stack for 3 or 9 wk to determine changes in concentrations of nitrogen fractions and digestibility in ruminants. Pepsin insoluble nitrogen concentration after 48 h of ruminal incubation was not changed by deep-stacking for 3 wk and only slightly elevated at 9 wk (-0.4, -0.2, -0.1, 2.2, 2.8, and 5.4 (SE 0.47) percentage unit difference between actual and predicted concentrations at 3 and 9 wk for 10, 20, and 40% soybean meal, respectively). Deep-stacking did not markedly alter in situ ruminal disappearance of broiler litter nitrogen. Conversely, in situ ruminal nitrogen disappearance of soybean meal substrates was decreased by deep-stacking; change was greater for 16 (-9.4, -13.0, -26.3, -12.5, -19.2, and -32.3; SE 0.57) than for 48 h of ruminal incubation (-3,3, -5,2, -9,4, -10,6, -17.1, and 30.8 (SE 1.35) percentage unit difference between actual and predicted concentrations at 3 and 9 wk for 10, 20, and 40% soybean meal, respectively). Sugar addition to soybean meal substrates did not appear to enhance rumen undegradable protein concentration (e.g., predicted intestinal nitrogen disappearance of 11.7, 12.6, 10.1, 34.3, 32.5, and 25.9% with low and high sugar and amino acid source levels for control, xylose and whey, respectively, at 3 wk; SE 0.89). In conclusion, these results suggest potential to markedly increase rumen undegradable protein in soybean meal and possibly other feedstuffs high in rumen digestibile protein by addition to broiler litter before deep-stacking.