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Evonik Animal Nutrition

Optimal tryptophan: lysine Ratio for 25-40 Kg Growing Pigs Fed Diets Containing 35 % Distillers Dried Grains with Solubles

Published: March 11, 2021
By: Author: J. Caroline González-Vega – Evonik Operations GmbH. John K. Htoo, n/a – Evonik Operations GmbH. Maryane S. Sespere Faria Oliveira, Postdoctoral Research Associate, University of Illinois. Hans H. Stein, Professor, Department of Animal Sciences, University of Illinois.
Distillers dried grains with solubles (DDGS) has a high concentration of Leu, and the Trp requirement for growing pigs may be increased if diets contain excess Leu. Therefore, the objective of this experiment was to determine the optimum standardized ileal digestible (SID) Trp:Lys ratio in growing pigs fed diets with excess Leu from DDGS. A diet based on corn, soybean-meal, and 35% DDGS was formulated to be deficient in Trp and Lys, according to NRC requirements (0.13% SID Trp; 0.88% SID Lys; 15% SID Trp:Lys ratio). Four diets were prepared by adding L-Trp to the basal diet, which resulted in analyzed SID Trp:Lys ratios of  18, 20, 23, and 24% in these diets. One-hundred and twenty growing pigs (26.3 ± 2.0 kg) were allotted to one of the 5 dietary treatments with 3 pigs per pen and 8 pen replicates in a completely randomized design. Diets were fed for 21d and blood samples were collected on d-21. Data were analyzed by linear and quadratic contrasts in SAS. The optimal SID Trp:Lys ratio was estimated using linear broken-line (LBL) and quadratic broken-line (QBL) regressions for ADG and G:F, using NLIN procedure in SAS. Results indicated that average daily feed intake, ADG, G:F, and final body weight increased (linear and quadratic, P < 0.01) and plasma-urea-nitrogen decreased (linear and quadratic, P < 0.05) as dietary SID Trp:Lys increased (Table 1). The SID Trp:Lys ratio to optimize ADG was 20.9 and 23.4% by LBL and QBL, respectively. The G:F was optimized at 18.7 and 20.2% by LBL and QBL, respectively. The average SID Trp:Lys ratio for the 4 measurements was 20.8% which is greater than the current NRC requirement (SID 17.3%). In conclusion, diets formulated with 35% DDGS may need more dietary Trp than current NRC values.
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Authors:
John Htoo
Evonik Animal Nutrition
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Caroline Gonzalez-Vega
Cargill
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Hans H. Stein
University of Illinois
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Stefano Calamanti
20 de julio de 2021
The immunotolerant action through the microbiome is also interesting as it allows Lactobacillus Alistipes to use tryptophan as an energy source. The product of this degradation is indoleamine 2-3 dioxygenase 1 which in turn activates the Ahr receptor (Aryl Hydrocarbon Receptor) whose activation allows the production of IL 22, IL 10.
Juarez Donzele
Universidade Federal de Viçosa - UFV
13 de abril de 2021
DR John Htoo, I think I was not clear enough in my considerations. My considerations were exactly highlighting the merit of the work for having used a suboptimal level of lysine. The suggestion that I made of using a reference treatment with lysine level in the animal's requirement, would be just to prove that the level of lysine in the test diets would be below the animal's requirement. I understand perfectly the correctness of maintaining the relationships of the other essential amino acids with the lysine just above that recommended in the ideal protein for the animal category, under study, thus guaranteeing lysine as the second limiting amino acid. I fully agree with the methodology used in this study, my intention was to highlight that detail.
Zdzislaw Mroz
5 de abril de 2021
Dear Hans, As your old professional partner from ID-DLO Lelystad (Wageningen University in The Netherlands) I am happy to know that you are still very active in the nutritional research on pigs. Your work I find very interesting and worthy to comment as follows: Optimizing Trp:Lys ratios in diets for grower pigs (without or with DDG) has been subjected to many studies across the world. From my perspective, in your study, it would be also interesting to monitor changes in dietary L-Trp provision in relation to stress-related parameters such as serotonin, cortisol and intestinal integrity. From our Dutch-American studies (see: Koopmans et al. in Journal of Animal Science, Volume 84, Issue 4, April 2006: 963–971) is known that supplemental dietary Trp (5 g/kg as fed basis) to piglets increased hypothalamic serotonergic activity, reduced the salivary cortisol response to mixing, improved intestinal morphology, and reduced physical activity 10 d after diet introduction. Consequently, diets containing high Trp levels improved neuroendocrine components of stress and increased gastrointestinal robustness. Besides, adding DDG with solubles to weaner/grower diets presumably influence on the degree of satiety and behavioural/well-being criteria. With friendly greetings. Zdzislaw Mroz
Juarez Donzele
Universidade Federal de Viçosa - UFV
12 de marzo de 2021
John Htoo, Based on the summary presented, I would like to highlight as correct, the decision of the team of researchers responsible for the work, to have used a suboptimal level of lysine to determine the best tryptophan relationship with lysine. This decision-making is justified by the fact that animals require grams of amino acids per day or phase, not percentage. Thus it can be deduced that the percentage is established based on an expectation of consumption and is adopted because of its practicality. If in the study of the relationship between any essential amino acid with lysine, an optimum level of lysine is used, there is a risk that the animal's feed consumption will be above the estimated, which would result in excess lysine consumption, which would compromise the result, underestimating the relationship. And exactly because of this reality, I think there was a lack of treatment, that is, using lysine in the requirement of the animal with tryptophan at 15% of the lysine, which would be used to prove its deficiency in the test diets.
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