Nutritional value of high protein ingredients fed to growing pigs in comparison to commonly used protein sources in swine diets.

Two experiments were conducted to test the hypothesis that 2 high protein dried distillers with solubles and yeast mass added (GDDY) products fed to growing pigs had comparable amino acid (AA) digestibility and metabolizable energy (ME) to feeds commonly used in swine diets. In Exp. 1, 7 barrows with initial body weight (BW) of 25 ± 0.8 kg were fitted with a simple T-cannula at the distal ileum to allow for digesta collection. Experimental diets were N-free diet and 6 cornstarch-based diets containing 6 ingredients as the sole source of AA: spray dried GDDY, ring dried GDDY, corn distillers dried grains with solubles (DDGS), soybean meal (SBM), enzymatically treated soybean meal (ESBM), and Fish meal (FM) provided at 4% of BW. The experiment was conducted as a 7 × 7 Latin square design with 7 collection periods of 7d (5d adaptation and 2d ileal digesta collection). In Exp. 2, a total of 28 barrows (28.8 ± 1.4 kg BW) were used in a 2-period switch back design with 7 diets and 4 replicate pigs in each period (n=8 reps/diet). Experimental diets were a corn-based basal diet and 6 corn-based diets containing spray dried GDDY, ring dried GDDY, DDGS, SBM, ESBM and FM. Fecal and urine samples were collected using the marker-to-marker approach for 5d after 7d of adaptation to determine ME concentration. Overall, SID values were within the mean +/- SD of NRC (2012) values for all ingredients evaluated. The SID of AA was greater (P < 0.05) in ESBM than the other protein feedstuffs (90.09% vs. 78.71 - 81.51%). There were not significant differences in SID of AA (P > 0.05) in SBM, FM, spray dried GDDY and ring dried GDDY (81.49, 78.71, 81.52, and 79.20 %). With respect to the most common first limiting AA for swine, the SID of Lys was greater (P < 0.05) in spray dried GDDY than ring dried GDDY and DDGS (83.56 vs. 77.33 and 68.53 %, respectively). There were not significant differences (P > 0.05) for ME in corn (3313 Kcal/kg), ESBM (3323 Kcal/kg), and FM (3454 Kcal/kg) when compared with spray dried GDDY and ring dried GDDY (3995 Kcal/kg and 3442 Kcal/kg respectively). However, spray dried GDDY had greater DE and ME when compared to SBM. Collectively, this study demonstrates that GDDY products have an AA profile and digestibility comparable to SBM; ME in GDDY products is not different than corn. Therefore, GDDY has potential as a feed ingredient for pigs, which could provide an alternative source of protein and energy in swine diets.