S. Thiruchchenthuran , N. Lopez-Villalobos , F. Zaefarian , M.R. Abdollahi , T.J. Wester , N.B. Pedersen , A.C. Storm , A.J. Cowieson , P.C.H. Morel
{"title":"基于肉鸡日粮总化学成分的回肠养分消化率和可消化养分含量预测方程评估","authors":"S. Thiruchchenthuran , N. Lopez-Villalobos , F. Zaefarian , M.R. Abdollahi , T.J. Wester , N.B. Pedersen , A.C. Storm , A.J. Cowieson , P.C.H. Morel","doi":"10.1016/j.anifeedsci.2024.115974","DOIUrl":null,"url":null,"abstract":"<div><p>The coefficient of apparent ileal digestibility (CAID) and ileal digestible contents (IDC) of nutrients of 56 diets using 10 feed ingredients were measured in broilers (21–24 d post-hatch). Diets contained varying inclusion levels of traditional and non-traditional ingredients and differed widely in chemical composition. The chemical composition and <em>in vivo</em> digestibility values were used to establish prediction equations for CAID and IDC of nutrients using stepwise multiple regression. The strength and accuracy of the developed equations were evaluated by root mean square error (RMSE), coefficient of determination (R<sup>2</sup>), adjusted R<sup>2</sup> (adj. R<sup>2</sup>), and Akaikie’s Information Criteria (AIC). The bootstrap method was used to validate the choice of variables by stepwise selection method in the original equation based on their frequencies of selection. Selection of variables was validated if the variables that appear in the original stepwise model were selected in more than 30% of the 1000 bootstrap samples. A close agreement between the original equations and bootstrap resampling was observed for CAID of nitrogen (N) and energy and IDC of energy, starch, and calcium (Ca). Additionally, the original data was subjected to another run of stepwise regression analysis using the selected variables by bootstrapping. The initial regression showed that the CAID of N and energy was highly dependent on crude fibre (CF) and energy contents of the diets. The CAID of energy can be predicted (R<sup>2</sup> = 0.89 and RMSE = 0.035) by CF, gross energy (GE), CF<sup>2</sup>, and starch-to-CF ratio (starch:CF). Calcium content had a positive influence, while phosphorus (P) content had a negative influence on the prediction of CAID of fat. The main variable to predict CAID and IDC of most nutrients was the dietary CF content. Based on the lowest RMSE and AIC, the best predictors for IDC of N were ash, N, fat, CF, CF<sup>2</sup>, and starch:CF, while the best predictors for IDC of energy were CF, GE, CF<sup>2</sup>, and starch:CF. The results of the original stepwise regression models and the stepwise regression with the selected variables from the bootstrap results for CAID of N, energy, fat, and DM, as well as IDC of energy, starch, and Ca, were the same with no differences in R<sup>2</sup>, Adj. R<sup>2</sup>, RMSE, and AIC. This method can be useful for developing stable and reproducible models using stepwise regression. However, an external validation is needed to confirm the use of these equations in commercial settings.</p></div>","PeriodicalId":7861,"journal":{"name":"Animal Feed Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0377840124001020/pdfft?md5=04aadb200963aa9b0b7bd3da1b0c4a0c&pid=1-s2.0-S0377840124001020-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Evaluation of equations for predicting ileal nutrient digestibility and digestible nutrient content of broiler diets based on their gross chemical composition\",\"authors\":\"S. Thiruchchenthuran , N. Lopez-Villalobos , F. Zaefarian , M.R. Abdollahi , T.J. Wester , N.B. Pedersen , A.C. Storm , A.J. Cowieson , P.C.H. Morel\",\"doi\":\"10.1016/j.anifeedsci.2024.115974\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The coefficient of apparent ileal digestibility (CAID) and ileal digestible contents (IDC) of nutrients of 56 diets using 10 feed ingredients were measured in broilers (21–24 d post-hatch). Diets contained varying inclusion levels of traditional and non-traditional ingredients and differed widely in chemical composition. The chemical composition and <em>in vivo</em> digestibility values were used to establish prediction equations for CAID and IDC of nutrients using stepwise multiple regression. The strength and accuracy of the developed equations were evaluated by root mean square error (RMSE), coefficient of determination (R<sup>2</sup>), adjusted R<sup>2</sup> (adj. R<sup>2</sup>), and Akaikie’s Information Criteria (AIC). The bootstrap method was used to validate the choice of variables by stepwise selection method in the original equation based on their frequencies of selection. Selection of variables was validated if the variables that appear in the original stepwise model were selected in more than 30% of the 1000 bootstrap samples. A close agreement between the original equations and bootstrap resampling was observed for CAID of nitrogen (N) and energy and IDC of energy, starch, and calcium (Ca). Additionally, the original data was subjected to another run of stepwise regression analysis using the selected variables by bootstrapping. The initial regression showed that the CAID of N and energy was highly dependent on crude fibre (CF) and energy contents of the diets. The CAID of energy can be predicted (R<sup>2</sup> = 0.89 and RMSE = 0.035) by CF, gross energy (GE), CF<sup>2</sup>, and starch-to-CF ratio (starch:CF). Calcium content had a positive influence, while phosphorus (P) content had a negative influence on the prediction of CAID of fat. The main variable to predict CAID and IDC of most nutrients was the dietary CF content. Based on the lowest RMSE and AIC, the best predictors for IDC of N were ash, N, fat, CF, CF<sup>2</sup>, and starch:CF, while the best predictors for IDC of energy were CF, GE, CF<sup>2</sup>, and starch:CF. The results of the original stepwise regression models and the stepwise regression with the selected variables from the bootstrap results for CAID of N, energy, fat, and DM, as well as IDC of energy, starch, and Ca, were the same with no differences in R<sup>2</sup>, Adj. R<sup>2</sup>, RMSE, and AIC. This method can be useful for developing stable and reproducible models using stepwise regression. 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Evaluation of equations for predicting ileal nutrient digestibility and digestible nutrient content of broiler diets based on their gross chemical composition
The coefficient of apparent ileal digestibility (CAID) and ileal digestible contents (IDC) of nutrients of 56 diets using 10 feed ingredients were measured in broilers (21–24 d post-hatch). Diets contained varying inclusion levels of traditional and non-traditional ingredients and differed widely in chemical composition. The chemical composition and in vivo digestibility values were used to establish prediction equations for CAID and IDC of nutrients using stepwise multiple regression. The strength and accuracy of the developed equations were evaluated by root mean square error (RMSE), coefficient of determination (R2), adjusted R2 (adj. R2), and Akaikie’s Information Criteria (AIC). The bootstrap method was used to validate the choice of variables by stepwise selection method in the original equation based on their frequencies of selection. Selection of variables was validated if the variables that appear in the original stepwise model were selected in more than 30% of the 1000 bootstrap samples. A close agreement between the original equations and bootstrap resampling was observed for CAID of nitrogen (N) and energy and IDC of energy, starch, and calcium (Ca). Additionally, the original data was subjected to another run of stepwise regression analysis using the selected variables by bootstrapping. The initial regression showed that the CAID of N and energy was highly dependent on crude fibre (CF) and energy contents of the diets. The CAID of energy can be predicted (R2 = 0.89 and RMSE = 0.035) by CF, gross energy (GE), CF2, and starch-to-CF ratio (starch:CF). Calcium content had a positive influence, while phosphorus (P) content had a negative influence on the prediction of CAID of fat. The main variable to predict CAID and IDC of most nutrients was the dietary CF content. Based on the lowest RMSE and AIC, the best predictors for IDC of N were ash, N, fat, CF, CF2, and starch:CF, while the best predictors for IDC of energy were CF, GE, CF2, and starch:CF. The results of the original stepwise regression models and the stepwise regression with the selected variables from the bootstrap results for CAID of N, energy, fat, and DM, as well as IDC of energy, starch, and Ca, were the same with no differences in R2, Adj. R2, RMSE, and AIC. This method can be useful for developing stable and reproducible models using stepwise regression. However, an external validation is needed to confirm the use of these equations in commercial settings.
期刊介绍:
Animal Feed Science and Technology is a unique journal publishing scientific papers of international interest focusing on animal feeds and their feeding.
Papers describing research on feed for ruminants and non-ruminants, including poultry, horses, companion animals and aquatic animals, are welcome.
The journal covers the following areas:
Nutritive value of feeds (e.g., assessment, improvement)
Methods of conserving and processing feeds that affect their nutritional value
Agronomic and climatic factors influencing the nutritive value of feeds
Utilization of feeds and the improvement of such
Metabolic, production, reproduction and health responses, as well as potential environmental impacts, of diet inputs and feed technologies (e.g., feeds, feed additives, feed components, mycotoxins)
Mathematical models relating directly to animal-feed interactions
Analytical and experimental methods for feed evaluation
Environmental impacts of feed technologies in animal production.