Chemical composition, energy, and amino acid digestibility in 7 cottonseed co-products fed to growing pigs

The objective of this study was to determine the chemical composition, DE and ME contents, and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA in 7 cottonseed co-products fed to growing pigs. The 7 cottonseed co-products were: cottonseed meals (solvent extracted) with CP level of 46%, 50%, and 55% (46CSM, 50CSM, and 55CSM), cottonseed protein with CP level of 50% and 55% (50CSP and 55CSP), fermented cottonseed meal (CSMF), and expelled cottonseed meal (CSME). The DE and ME contents of the 7 test ingredients were measured using 48 crossbreed barrows (BW: 44.1 ± 4.2 kg) and 8 diets (including a corn-soybean meal basal diet) in a completely randomized design. The AID and SID of AA of the 7 test ingredients were determined using 7 crossbreed barrows (initial BW: 67.4 ± 8.5 kg) in a 6 × 8 Youden square design with 6 periods and 8 diets (including one N-free diet). The DE and ME values of the 7 cottonseed co-products varied from 12.72 to 15.63 MJ/kg and 12.24 to 14.83 MJ/kg, respectively. Among the 7 cottonseed co-products, 55CSP and CSME had the greatest (P < 0.05) ME and DE values compared to the other cottonseed co-products. In addition, 55CSP had the greatest (P < 0.05) AID and SID of all the AA tested except for Gly and Pro. In contrast, 46CSM or 55CSM had the lowest (P < 0.05) AID and SID of all the AA tested except for Gly and Pro. The 55CSP also had the greatest (P < 0.05) concentrations of standardized ileal digestible CP and all the AA tested except for Gly and Pro. In conclusion, the chemical composition, energy, and AA digestibility of cottonseed co-products with different processing techniques varied widely. Based on the energy and AA digestibility, cottonseed protein with CP level of 55% is a better dietary ingredient for growing pigs compared with the other cottonseed co-products.