Determination And Prediction Of Energy And Amino Acid Digestibility In Different Processing Corn Distillers Dried Grains With Solubles Of China Fed To Growing Pigs

In this study, we want to find the relationship between processing and available energy and amino acids quality of corn distillers dried grains with solubles (DDGS). Exp.1and2, the study was conducted to determine the digestible energy (DE) and metabolizable energy (ME) content of25samples of corn dried distillers grains with solubles when fed to growing pigs and to generate prediction equations for DE and ME based on chemical analysis. The25corn DDGS samples included15full-oil (no oil extracted) DDGS and10de-oiled (oil extracted) DDGS collected from17ethanol plants in China. A corn-soybean meal diet constituted the basal diet and the other25diets replaced a portion of the corn, soybean meal and lysine of the basal diet with28.8%of one of the25corn DDGS. Seventy-eight barrows (Duroc×Large White×Landrace, initial BW=42.6±6.2kg) were used in the experiment conducted over2consecutive periods (n=6) using a randomized complete design. Based on EE content and processing, the25samples were divided into full-oil and de-oiled DDGS classes. Using a stepwise regression analysis, a series of DE and ME prediction equations were developed not only among the25DDGS but also within the15full-oil DDGS and10de-oiled DDGS samples. The best fit equations of DE (kcal/kg DM) for the complete set of25DDGS,15full-oil DDGS and10de-oiled DDGS were DE=1,874-(21.35×%NDF)+(0.65×%GE)-(99.84×%CF)[R2=0.86, SE=99.94], DE=-643-(94.52×%CF)+(1.14×%GE)-(22.89×%NDF)[R2=0.83, SE=112.79] and DE=4,338-(36.75×%NDF)+(32.99×%CP)-(67.10×%CF)[R2=0.95, SE=62.08]. The best fit equations for ME (kcal/kg DM) for the complete set of25DDGS,15full-oil DDGS and10de-oiled DDGS were ME=1,463-(32.43×%NDF)+(0.79×%GE)-(54.52×%ash)-(68.82×%CF)[R2=0.87, SE=115.09], ME=7,898-(42.08×%NDF)-(136.17×%ash)+(101.19×%EE)-(103.83×%CP)[R2=0.90, SE=100.70] and ME=4,066-(46.30×%NDF)+(45.80×%CP)-(106.19×%ash)[R2=0.94, SE=86.20]. Using the sum of squared residuals (Q) to compare the accuracy of the3groups of prediction equations, it was found that equations for full-oil DDGS and de-oiled DDGS were better than those based on the entire set of DDGS and should be used when it was possible to partition the sample set. Exp.3, the experiment was to determine and compare the digestibility of crude protein and amino acids in full-oil DDGS and de-oiled DDGS and with different condensed distillers solubles (CDS) ratios.12barrows (Duroc×Large White×Landrace, initial BW=29.6±2.3kg) fitted with ileal T-cannula were allotted into two6×6Latin square designs. Each period comprised a5-d adaption period followed by a2-d collection of ileal digesta. The five test diets contained62%DDGS as the sole source of AA. Another nitrogen-free diet was used to measure the basal endogenous losses of CP and AA. Chromic oxide (0.3%) was used as an inert marker in each diet. The results showed that SID CP and SID AA of full-oil DDGS were higher (P<0.01) than the de-oiled DDGS, but the partly de-oiled DDGS and partly germ meal DDGS had no difference with the full-oil DDGS. In exp.4, Twelve barrows (Duroc x Large White x Landrace, initial BW=37.1±4.7kg) were used to determine the net energy (NE) value of5corn DDGS, and establish prediction equations for NE content of ingredients. Pigs received one corn-soybean meal basal diet and five experimental diets containing5different DDGS, respectively. Measurements were conducted on6pigs per experimental diets. The average NE values for the5DDGS were2,733,2,935,2,803,2,446and2,317kcal/kg DM, respectively. Stepwise regression analysis performed by the chemical composition and the NE value of the ingredients, the NE values could be accurately predicted from the chemical characteristics. The best fit equations were as follows:NE (kcal/kg DM)=-740-(43.82×%CF)+(161.98×%ash)+(0.765×DE), with R2=1.00, residual standard deviation (RSD)=1.25, and P<0.01. Exp.4also test and verified the prediction equations made in exp.2using the new5DDGS, the results showed that it’s good for predict the de-oiled DDGS, but not very well for the full-oil DDGS. Above all, the corn DDGS produced in China had big variations in chemical composition, DE and ME and NE, SID values of CP and amino acids, but be classified by their processing and do experiments, it was better to achieve more accurate data and predictions.