The objective was to determine the effects of drying and blanching methods on the nutrient utilization of black soldier fly larva (BSFL; Hermetia illucens) meal by pigs using in vitro assays. Two-step and three-step in vitro assays were employed to simulate the gastrointestinal tract of pigs. Four BSFL meals were prepared using the following pretreatment methods: (1) microwave drying at 80 °C for 32 min, (2) hot-air drying at 60 °C for 17 h, (3) blanching for 5 min in boiling water and hot-air drying at 60 °C for 17 h, and (4) 2% citric acid solution blanching for 5 min in boiling solution and hot-air drying at 60 °C for 17 h. After the drying process, each BSFL was defatted and ground to obtain BSFL meals. The nitrogen (N) concentration in the test ingredients ranged from 8.5 to 9.4%, and the ether extract ranged from 6.9 to 11.5% on an as-is basis. The amino acid (AA) concentration in the BSFL meals ranged from 2.80 to 3.24% for Lys and 0.71 to 0.89% for Met on an as-is basis. Hot-air-dried BSFL meal had a greater in vitro ileal disappearance (IVID) of N compared with microwave-dried BSFL meal (p < 0.05). However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying had a lower (p < 0.05) IVID of N compared with microwave-dried or hot-air-dried BSFL meal. Blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) in vitro total tract disappearance of dry matter and organic matter compared with microwave-dried or hot-air-dried BSFL meal. Microwave-dried BSFL meal had a lower (p < 0.05) IVID of indispensable AA, except for His, Lys, Met, and Phe, compared with hot-air-dried BSFL meals. However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) IVID of indispensable AA compared with microwave-dried or hot-air-dried BSFL meal. In conclusion, hot-air-dried BSFL meal presented greater nutrient utilization compared with microwave-dried BSFL meal for pigs. However, blanching in water or citric acid solution negatively affected the nutrient digestibility of BSFL meal based on in vitro assays.

The present work aimed to assess the nutrient digestibility of soybean meal (SBM) products based on in vitro procedures. Two-step and three-step in vitro assays were performed to mimic the digestion and absorption of nutrients in the digestive tracts of growing swine. The two-step in vitro method was modified to reflect the digesta retention time and digestive enzymes of nursery piglets by decreasing incubation periods and digestive enzymes to half of those in the procedure for growing pigs and was used to determine the crude protein (CP) digestibility of nursery piglets. The seven ingredients included conventional SBM, thermo-mechanically processed SBM (TSBM), and five sources of fermented SBM (FSBM). The five sources of FSBM were produced using different microorganisms for fermentation, namely: (1) Pediococcus pentosaceus and Bacillus subtilis, (2) Enterococcus faecium (FSBM-EF), (3) Aspergillus oryzae and Bacillus subtilis, (4) Aspergillus oryzae, and (5) Bacillus licheniformis. Based on the conventional procedure, the in vitro ileal disappearance of CP in TSBM was greater (p < 0.05) compared with that in FSBM sources. Based on the in vitro assays for total tract digestibility, organic matter in TSBM was better digested (p < 0.05) compared with that in FSBM except for FSBM-EF. Based on the in vitro procedure for nursery piglets, the ileal disappearance of CP in TSBM was greater (p < 0.05) than that in the other SBM products. Taken together, thermo-mechanical processing rather than microbial fermentation of SBM improves the nutrient digestibility of SBM, particularly in nursery pigs.

The objectives were to determine the effects of graded inclusion rates of wheat bran (WB) on apparent ileal (AID), apparent total tract (ATTD), and hindgut digestibility of nutrients and tested the influence of ileal digesta collection on proceeding fecal nutrient digestibility in pigs. Six barrows with an initial mean body weight of 70.7 ± 5.7 kg fitted with an ileal T-cannula were used. The animals were assigned to a replicated 3 × 3 Latin square design with three diets and three periods. A basal diet was based mainly on wheat, soybean meal, and cornstarch. Two additional diets were formulated to contain 20 or 40% of WB at the expense of cornstarch. Each experimental period consisted of a seven-day adaptation period and a four-day collection period. After the adaptation period, fecal samples were collected on day 8, and ileal digesta were collected on days 9 and 10. Another set of fecal samples was collected on day 11 to determine the influence of ileal digesta collection on proceeding total tract nutrient digestibility. The AID of energy, dry matter (DM), organic matter (OM), crude protein, and phosphorus linearly decreased (p < 0.05) with an increasing inclusion rate of WB from 0 to 40%. The ATTD of energy, DM, OM, crude protein, ether extract, and phosphorus linearly decreased (p < 0.01) as the inclusion rate of WB increased. Hindgut digestibility of DM, OM, and ether extract linearly increased (p < 0.05) with an increasing inclusion rate of WB. The ATTD of GE and most nutrients did not differ between the two fecal collection periods of before and after ileal digesta collection. Taken together, the inclusion of a fiber-rich ingredient reduced ileal and fecal digestibility of nutrients but increased hindgut digestibility of some nutrients, and total tract digestibility of nutrients did not differ whether the fecal samples were collected before or after two days of ileal digesta collection in pigs.

The objectives were to evaluate previous equations for estimating gross energy (GE) of pig urine using urinary nitrogen (N) and to develop novel equations for estimating GE concentrations of pig urine. A total of 136 urine samples were obtained from pigs fed 18 diets in 2 experiments. The samples were analyzed for GE and N concentrations. The accuracy of previous equations was assessed by regressing the measured values minus the predicted values for urinary GE concentration on the predicted values centered to the mean. Novel equations for estimating the urinary GE concentration were developed using urinary N concentration and body weight (BW) as independent variables. The previous equations overestimated (mean bias; p<0.001) urinary GE concentrations and the overestimation was more pronounced for the low-GE urine samples (linear bias; p<0.001). The novel equations developed in the present work were: urinary GE concentration (kcal/kg) = –7.51+12.83×urinary N (r2 = 0.92 and p<0.001) and –16.33+14.00×urinary N+0.192×BW–0.030×urinary N×BW (R2 = 0.92 and p<0.001) where N as g/kg and BW as kg. Overall, the previous equations overestimate urinary GE, particularly for low-GE urine of pigs. Gross energy concentrations in urine can be fairly accurately estimated using urinary N concentration and BW.

Objective: The present study aimed to measure fecal and urinary phosphorus (P) excretion from pigs and to develop prediction models for P excretion of pigs.Methods: A total of 96 values for P excretions were obtained from pigs of 15 to 93 kg body weight (BW) fed 12 diets in four experiments and were used to develop the prediction models. All experimental diets contained exogenous phytase at 500 phytase units per kg. Body weight of pigs and dietary P concentrations were used as independent variables in the prediction models.Results: The BW, feed intake, and P intake were positively correlated with total (fecal plus urinary) P excretions (r = 0.80, 0.91, and 0.94, respectively; p<0.001). The models for estimating P excretion were: fecal P excretion (g/d) = –0.654–0.000618×BW2+0.273×BW ×dietary P concentration (R2 = 0.83; p<0.001); urinary P excretion (g/d) = 0.045+ 0.00781×BW×dietary P concentration (R2 = 0.15; p<0.001); total P excretion (g/d) = –0.598–0.000613×BW2+0.280×BW×dietary P concentration (R2 = 0.86; p<0.001) where the BW of pigs and dietary P concentration are expressed as kg and % (as-fed basis), respectively. Based on the developed prediction models, the estimated annual fecal, urinary, and total P excretion for a market pig was 1.24, 0.09, and 1.33 kg/yr, respectively.Conclusion: The P excretions in market pigs can be estimated using BW of pigs and dietary P concentration. In the present model, a market pig excretes 1.24 kg of fecal P and 0.09 kg of urinary P per year.

Background: An accurate determination of fiber concentrations in feeds and feces is critical for the measurement of fiber digestibility in pigs. The method of AOAC INTERNATIONAL for determining amylase-treated neutral detergent fiber (aNDF; Method 2002.04) has been widely used for pig diets. To overcome the complexity of the AOAC procedure, the Ankom method is also available for determining aNDF. Although these two methods have been compared for ruminant diets and feces, a comparison of the methods for pig diets and feces has not been documented. Objective: The objective was to compare aNDF values determined by the AOAC (aNDFAOAC) and the Ankom methods (aNDFAnkom) of ingredients, diets, and feces for pigs. Methods: A total of 255 test samples, consisting of 26 feed ingredients, 39 diets, and 190 feces of pigs, were analyzed for aNDF. To compare the AOAC Method 2002.04 and Ankom methods for aNDF, regression analyses were performed with the aNDFAnkom minus the mean aNDFAnkom as an independent variable and the aNDFAOAC minus the aNDFAnkom as a dependent variable. Results: The aNDFAnkom were greater than the aNDFAOAC by 2.90% (standard error = 0.63; P < 0.001) on average for ingredients and by 2.56% (standard error = 0.34; P < 0.001) on average for diets. For feces, the aNDFAnkom were greater than the aNDFAOAC by 1.30% (standard error = 0.32; P < 0.001) on average. The differences between the aNDFAnkom and aNDFAOAC were not consistent across the data ranges represented by a linear bias (slope = –0.16; standard error = 0.04; P < 0.001) in feces. Conclusion: ANDF concentrations determined by the Ankom method were greater than from the AOAC method in pig feeds and feces. Highlights: Despite convenience, the Ankom method yields greater aNDF values compared with the AOAC method.