Objective: The experiment was conducted to determine the apparent or standardized ileal digestibility (AID or SID) of crude protein (CP) and amino acids (AA) in 10 rapeseed cake samples fed to pigs, and to construct predictive models for the SID of CP and AA based on the chemical composition of rapeseed cakes. Methods: Twenty-two cannulated pigs (initial body weight: 39.8 ± 1.2 kg) were assigned to two 11 × 3 incomplete Latin square designs, including an N-free diet and 10 diets containing rapeseed cake. Each experimental period included 5 days of adaptation and 2 days of ileal digesta collection. Titanium dioxide (TiO₂) was added at 0.3% to all the diets as an indigestible marker for calculating the ileal CP and AA digestibility. Results: The coefficients of variation (CV) of the content of crude fat (EE), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and total glucosinolates (TGS) in 10 samples of rapeseed cake were greater than 10%. The standardized ileal digestibility (SID) of crude protein (CP), lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) in rapeseed cake was 73.34% (61.49 to 81.12%), 63.01% (41.41 to 73.10%), 69.47% (50.55 to 88.16%), 79.61% (74.41 to 87.58%), and 94.43% (91.34 to 97.20%), respectively. The best prediction equations for SID_CP, SID_Lys, and SID_Val were as follows: SID_CP = 90.124 − 0.54NDF (R² = 0.58), SID_Lys = 100.107 − 1.229NDF (R² = 0.94), and SID_Val = 151.012 − 2.990TGS (R² = 0.57). Conclusion: Overall, great variation exists among the 10 rapeseed cakes, and the NDF, TGS, and heating temperature can be used as the key predictors for the SID of CP and AA.

Objective: The experiment aimed to determine the standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in 10 brown rice samples fed to pigs, and to construct predictive models for SID of CP and AA based on the physical characteristics and chemical composition of brown rice.Methods: Twenty-two cannulated pigs (initial body weight: 42.0±1.2 kg) were assigned to a replicated 11×3 incomplete Latin square design, including an N-free diet and 10 brown rice diets. Each period included 5 d adaptation and 2 d ileal digesta collection. Chromic oxide was added at 0.3% to all the diets as an indigestible marker for calculating the ileal CP and AA digestibility.Results: The coefficients of variation of all detected indices for physical characteristics and chemical composition, except for bulk weight, dry matter (DM) and gross energy, in 10 brown rice samples were greater than 10%. The SID of CP, lysine (Lys), methionine, threonine (Thr), and tryptophan (Trp) in brown rice was 77.2% (62.6% to 85.5%), 87.5% (80.3% to 94.3%), 89.2% (78.9% to 98.9%), 55.4% (46.1% to 67.6%) and 92.5% (86.3% to 96.3%), respectively. The best prediction equations for the SID of CP, Lys, Thr, and Trp were as following, SIDCP = –664.181+8.484×DM (R2 = 0.40), SIDLys = 53.126+6.031×ether extract (EE)+0.893×thousand-kernel volume (R2 = 0.66), SIDThr = 39.916+7.843×EE (R2 = 0.41), and SIDTrp = –361.588+4.891×DM+0.387×total starch (R2 = 0.85).Conclusion: Overall, a great variation exists among 10 sources of brown rice, and the thousand-grain volume, DM, EE, and total starch can be used as the key predictors for SID of CP and AA.

To determine values for the digestible indispensable amino acid score (DIAAS), it is recommended that ileal amino acid (AA) digestibility values obtained in growing pigs are used to characterise protein quality in different foods. Therefore, an experiment was conducted to determine the standardised ileal digestibility (SID) of AA in eight energy ingredients (barley, sorghum, wheat, brown rice, rice bran, wheat bran, cassava and paddy rice) fed to pigs, where SID values in pigs can be used to calculate approximate DIAAS values in humans. Among the data obtained for all energy ingredients, significant variations ( P < 0·01) in CP and AA composition were observed. Rice bran and wheat bran had the highest CP (16·43 % and 18·16 %, respectively) and DIAAS scores of 81–88 for adult, qualifying as ‘good’ protein sources (> 75). Cassava, with the lowest CP (2·74 %), was limited by sulphur amino acid (54). Lysine (Lys) was the first-limiting AA in barley (74), sorghum (51) and wheat (49), with SID values lowest in wheat (71·04 %). Brown rice and paddy rice showed higher SID _Lys (87·51 % and 78·13 %, respectively). These findings highlight the potential of bran-based ingredients and Lys fortification to improve protein quality in grain-dependent diets, providing the scientific basis to combat protein malnutrition.

Objective: This experiment was conducted to determine the apparent ileal digestibility or standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in 10 rice brans fed to pigs, and to construct predictive models for the SID of CP and AA based on the chemical composition of rice bran.Methods: Twenty-two healthy (Duroc×[Landrace×Yorkshire]) pigs equipped with ileal Tcannulas (initial body weight: 30±1.5 kg) were selected for this experiment. A replicated 11×3 incomplete Latin square design was adopted. The experiment consisted of 3 periods each lasting for 7 days and had 11 dietary treatment groups. The diets included 10 rice bran diets as well as a nitrogen-free diet for determining endogenous losses of AA, and each treatment group had 6 replicates. Titanium dioxide was added to each diet as an indicator at a concentration of 0.3%.Results: Except for dry matter (DM) and total phosphorus (TP), the coefficients of variation for the chemical components among 10 rice bran sources were all greater than 10%. The SID of CP, Lys, Met, Thr, and Trp in rice bran was 81.89%±6.23, 80.33%±2.21, 83.25%±5.51, 79.89%±5.68, and 72.12%±4.71, respectively. The best prediction equations for the SID of CP and four limiting AA in rice bran are as follows: SIDCP = 974.032–29.805TP–9.496DM (R2 = 0.88), SIDLys = 471.278–9.267TP–4.245DM+1.401dummy variable (R2 = 0.92), SIDMet = 122.281–2.712CP (R2 = 0.51), SIDThr = 51.864+2.204GE–1.324CF ([R2 = 0.97]; GE, gross energy; CF, crude fiber), and SIDTrp = 73.912–23.268Calcium–0.336NDF+0.318TS ([R2 = 0.96]; NDF, neutral detergent fiber; TS, total starch).Conclusion: There was significant variability among the chemical components of 10 different sources of rice bran. Moreover, GE, DM, CP, TP, TS, CF, and NDF could serve as crucial predictors for the SID of AA.

Variations in available energy among cereal grains for growing pigs may originate from digestive and fermentative heterogeneities. This study employed an intestinal dual-cannulation to investigate the segmental disappearance of energy and nutrients along the gastrointestinal tract (GIT) and the gut microbial responses, aiming to elucidate how such heterogeneity influences available energy. Fourteen dual-cannulated pigs (21.91 ± 4.00 kg) were allotted to a replicated 3 × 7 incomplete Latin square design with seven iso-digestible energy and protein diets containing barley, brown rice, corn, oats, paddy rice, sorghum, and wheat as the sole grain, , and three 14-d periods consisting of 8 d adaptation and 2 d collection of feces, cecal digesta, and ileal digesta collection. The brown rice diet showed greater apparent digestibility and pre-ileal disappearance of dry matter (DM), organic matter (OM), and gross energy (GE) than the oat and paddy rice diets (P<0.05), contributing more available energy. High-fermentability wheat fiber was degraded mainly in the cecum, while low-fermentability oat and paddy rice fibers were degraded primarily in the colon. Distinct cereals selectively modulated gut microbiota: barley increased ileal and fecal Lactobacillus and cecal Bacteroidota; oats increased ileal Actinobacillus; corn elevated cecal Turicibacter and Romboutsia; and paddy rice increased cecal Phascolarctobacterium. Correlation analysis indicated that Bacteroidota, Prevotella, Alloprevotella, Anaerovibrio, and Phascolarctobacterium were positively associated with cecal soluble dietary fiber (SDF) disappearance, whereas Clostridium_sensu_stricto_1, Turicibacter, Escherichia-Shigella, Romboutsia, and Terrisporobacter were positively correlated with cecal insoluble dietary fiber (IDF) and cellulose disappearance. Short-chain fatty acid (SCFA) production was closely related to Bacteroidota, Clostridium_sensu_stricto_1, Actinobacillus, Veillonella, and Prevotella in the ileum; Turicibacter and Romboutsia in the cecum; and Lactobacillus in the feces. In conclusion, digestive and fermentative heterogeneities among cereal grains alter energy supply patterns: brown rice efficiently supplies energy via foregut digestion, while oats and paddy rice show low energy supply efficiency owing to poor digestibility and fermentability. Distinct cereals selectively regulate gut microbiota and metabolic outputs, underpinning their differential energy availability.