@article{rubio_kuneff_soler_espinosa_koutsos_heugten_2025, title={17 Assessing the functional potential of black soldier fly (Hermetia illucens) larvae frass in nursery pigs}, DOI={10.1093/jas/skaf102.091}, abstractNote={Abstract Frass, a nutrient-rich byproduct of black soldier fly (Hermetia illucens) larvae production, consists of exoskeleton shedding, processed larvae, residual dietary substrate, and larvae excretions. It is emerging as a sustainable ingredient with potential health and growth benefits in animal nutrition. A total of 160 nursery pigs (initial BW of 6.49±0.09 kg) weaned at 21 days were used in a 6-week study to evaluate the effect of increasing dietary levels of frass on growth performance, diarrhea scores, and serological indices. Pigs were randomly assigned within sex and BW blocks to 4 dietary treatments using 40 pens (4 pigs/pen; 10 replicates/treatment). Diets were prepared from a common basal mix and fed in 3 phases of 2 weeks each and included:: 1) positive control (PC) with 20%, 25, and 30% soybean meal for Phase 1-3, respectively; 2) a negative control (NC) with 25%, 30, and 35% soybean meal for Phase 1-3, respectively and no added frass; 3) NC with 3% frass; and 4) NC with 6% frass. Soybean meal replaced a portion of complex protein sources for Phase 1 and 2. Frass primarily replaced corn and crystalline amino acids and contained 30.56% crude protein, 8.03% crude fat, 32.34% NDF, 1.26% Ca, and 0.96% P. On days 4, 7, and 14, individual fecal samples were obtained using fecal loops and were evaluated on a scale of 1 to 5 representing hard, normal, soft, watery soft, and watery liquid feces, respectively. Scores were grouped into a dichotomous scale with scores of 1 to 3 indicating no diarrhea and scores of 4 to 5 indicating diarrhea for analysis using a chi-square test. Blood samples were collected on day 42 from 1 median pig/pen and analyzed for serum chemistry and cytokine analysis. Increasing dietary soybean meal reduced ADFI in Phase 1 (328 vs. 364 g/d; P=0.042) but no other effects (P>0.190) of soybean meal on BW, ADG, ADFI, or gain:feed ratio were detected. Dietary inclusion of frass had no impact (P>0.340) on growth performance. The incidence of diarrhea was 31.3, 70.6, and 61.9 for days 4, 7, and 14 respectively and was not affected by dietary treatments (chi-square P>0.453). Serum concentrations on day 7 showed that increasing frass levels led to a linear rise in ALT (SGPT), BUN, and BUN/CREAT ratio, while phosphorus, glucose, and amylase declined. Cytokine concentrations were generally unaffected, except on Day 7, where significant quadratic differences were noted for several cytokines (TNFα, IL-1α IL-1β, IL-4, IL-10, IL-12, IL-18, IL-2, and IL-6). On Day 42, TNFα showed quadratic differences (p≤0.0127), while IL-12 exhibited a linear increase (p≤0.0079). Accordingly, increasing frass levels may serve as an alternative animal protein source, supporting growth performance and health in diets for nursery pigs.}, journal={Journal of Animal Science}, author={Rubio, Sarah and Kuneff, Izadora B Batista and Soler, Fernando and Espinosa, Charmaine and Koutsos, Liz and Heugten, Eric}, year={2025}, month={May} }
 @article{soler_rubio_kuneff_sharara_malheiros_heugten_2025, title={34 Use of recycled ash from swine waste as a potential alternative dietary phosphorus source for pigs}, volume={103}, DOI={10.1093/jas/skaf102.096}, abstractNote={Abstract Excess phosphorus excretion in manure can have negative environmental consequences, but could be recycled into the diet as a valuable dietary nutrient. Therefore, this study evaluated the potential of feeding recycled ash from swine lagoon sludge as an alternative phosphorus (P) source for swine. Fifty-six individually housed pigs (BW of 44.14±4.11 kg) were blocked by sex and initial BW and randomly assigned within blocks to 7 dietary treatments (8 blocks/treatment). Treatments consisted of a negative control diet (NC; 0.45% Ca and 0.12% available P representing 40% of the requirement), and the NC supplemented with either monosodium phosphate (MSP) or ashed swine lagoon sludge (ASLS) to provide an additional 0.05%, 0.10%, and 0.15% of total P, while maintaining a constant Ca:P ratio. Ash was produced through combustion reaching a peak temperature of 1800°C. Analyzed concentrations of Ca and P in ASLS were 8.42% and 9.31%, respectively. Diets were formulated using MSP, ASLS, limestone, salt, and fine sand while keeping other ingredients equal. Pigs were limit-fed at 3 times maintenance, calculated as 197 kcal ME/kg BW0.60 based on average BW for each block. Feed was provided twice daily for the 35-d study. Diet analysis showed that the NC diet exceeded targeted Ca and P concentrations and this diet was excluded from statistical analysis. Thus, data were analyzed as a 2×3 factorial arrangement with source (MSP or ASLS) and level (0.05, 0.10, and 0.15%) as factors. Final BW and overall average daily gain were not affected by treatments (P >0.27). Serum P concentrations linearly increased (P=0.022) in pigs supplemented with MSP (8.13, 8.53, 8.90 mg/dL) and tended to increase with ASLS supplementation (P=0.098; 8.26, 8.64, 8.79 mg/dL). Slope-ratio analysis for serum P indicated a bioavailability of P of 68.89% for ASLS. Analyzed P concentrations (DM basis) in feces increased linearly with the addition of P from MSP (P< 0.001; 1.79, 1.96, and 1.99%) and ASLS (P=0.014, 1.78, 1.85, 2.00 %) but there was no difference between sources (P=0.809). Apparent total tract digestibility of P increased (P< 0.001) with added P for both MSP (39.30, 48.23, and 48.56%) and ASLS (40.67, 46.39, and 48.17%) with no difference between sources (P=0.722). Third metacarpal bone breaking force increased linearly with increasing P from MSP (P< 0.001; 75.06, 99.90, and 114.89 kg) but not from ASLS (P=0.695; 98.11, 96.86, and 102.11 kg). Dry matter of the third metacarpal bone was not affected by treatment, but bone ash linearly increased (P=0.012) with additional P from ASLS (47.07, 48.20 and 48.70%), but not from MSP (P=0.135; 47.57, 48.03, and 48.52%). Results indicate that ASLS has reduced bioavailability compared to MSP as the standard, but can be used as an alternative dietary P source if approved as a feed ingredient.}, journal={Journal of Animal Science}, author={Soler, Fernando and Rubio, Sarah and Kuneff, Izadora B Batista and Sharara, Mahmoud and Malheiros, Ramon and Heugten, Eric}, year={2025}, month={May}, pages={89–90} }
 @article{soler_galvez_rubio_kuneff_wilcock_heugten_2025, title={PSIII-13 Evaluation of reduced dietary crude protein and amino acid concentrations in diets for nursery pigs}, DOI={10.1093/jas/skaf102.333}, abstractNote={Abstract Reducing crude protein (CP) in diets for nursery pigs exposed to enteric challenges has been suggested to decrease pathogenic bacterial proliferation, diarrhea, morbidity, and mortality. This study evaluated the effects of feeding reduced CP by lowering amino acid (AA) concentrations in the post-weaning diet on growth performance, feed efficiency, and diarrhea incidence in nursery pigs and further evaluated whether increasing amino acid concentrations in the subsequent diet could recover potential lost performance through compensatory growth. Weaned pigs (n=180; 21-day old; BW=6.63±1.32 kg) were randomly assigned within sex and BW blocks to 1 of 4 dietary treatment combinations using 60 pens (3 pigs/pen; 15 replicates/treatment). Treatment combinations consisted of a low or high CP Phase 1 (P1) diet (1.05 and 1.45% standardized ileal digestible (SID) lysine; 17.7 and 22.0% CP, respectively) fed for 2 weeks, and within each, a low or high CP Phase 2 (P2) diet (1.30 and 1.45% SID lysine; 19.9 and 21.9% CP, respectively) fed for 3 weeks. Reductions in CP and SID AA content were made by decreasing dietary soybean meal and crystalline AA. Reducing CP and AA in P1 decreased (P< 0.001) BW (8.60 vs. 9.52 kg), ADG (140.8 vs. 207.1 g/d), ADFI (232.5 vs. 282.0 g/d), and gain:feed (593.4 vs. 730.0 g/kg) at the end of P1. Overall, final BW (20.37 vs. 21.55 kg; P=0.029), ADG (392.5 vs. 426.4 g/d; P=0.026), ADFI (574.3 vs. 610.8 g/d; P=0.008), but not gain:feed (684.5 vs. 704.1; P=0.162), were decreased by low CP and AA in P1, independent of P2 treatment. Increasing CP and AA in P2 decreased ADFI (793.0 vs. 853.1 g/d; P=0.013) and increased gain:feed (707.7 vs. 668.9 g/kg; P=0.003) for P2. Overall, feeding greater CP and AA decreased ADFI (567.3 vs. 617.8 g/d; P=0.008) and increased gain:feed (716.0 vs. 672.5 g/kg; P=0.003) without affecting ADG or final BW, regardless of P1 treatment. Individual pig fecal scores were determined using fecal loops on d 4, 7, 14, 18, and 21 using a scale of 1 to 5 representing hard, normal, soft, watery soft, and watery liquid feces. Scores were collapsed into a dichotomous scale with scores 1-3 representing no diarrhea and scores 4-5 representing diarrhea and analyzed using chi-square analysis. Diarrhea incidence peaked (P< 0.001) on d7 (78.3%) and was lowest on d28 (22.5%). Feeding low CP during P1 reduced the incidence of diarrhea on d14 (P=0.036; 23.9 vs. 31.7%) and the low CP P2 diet reduced diarrhea on d21 (P=0.048; 16.7 vs. 23.9%). In conclusion, incidence of diarrhea was reduced by feeding lower dietary CP concentrations. However, limiting amino acids to reduce CP immediately post-weaning negatively affected growth performance, which could not be recovered by increasing amino acid supply above requirements in the subsequent diet.}, journal={Journal of Animal Science}, author={Soler, Fernando and Galvez, Laura and Rubio, Sarah and Kuneff, Izadora B Batista and Wilcock, Pete and Heugten, Eric}, year={2025}, month={May} }
 @article{rubio_kuneff_soler_espinosa_koutsos_heugten_2024, title={PSIV-A-11 Potential of black soldier fly (<i>Hermetia illucens</i>) larvae frass as a functional ingredient for nursery pigs}, volume={102}, DOI={10.1093/jas/skae102.415}, abstractNote={Abstract Frass is the leftover material from the production of black soldier fly larvae (BSFL), which includes chitin-containing exoskeleton shedding, small, processed larvae, leftover dietary substrate, and larvae excrement. A total of 120 nursery pigs (initial body weight of 6.85 ± 0.10 kg) weaned at 21 d of age were used in a 6-wk study to evaluate the effect of increasing dietary levels of frass on growth performance, diarrhea score, and serological indices. Pigs were randomly assigned within sex and body weight blocks to 1 of 3 dietary treatments using 30 pens (4 pigs/pen; 10 replicates/treatment). Diets were prepared from a common basal and fed in 3 dietary phases of 2 wk each and included: 1) a control diet based primarily on corn and soybean meal; 2) the control with 3% added frass; and 3) the control with 6% added frass. On d 4, 7, and 14, individual fecal samples were obtained using fecal loops and were evaluated on a scale of 1 to 5 representing hard, normal, soft, watery soft, and watery liquid feces, respectively. Blood samples were collected on d 42 from 1 median pig per pen for the analysis of serum chemistry. Data were analyzed using the mixed model procedures as a randomized complete block design using linear and quadratic contrast comparisons to determine the effects of frass. Supplementation of frass linearly increased average daily gain (ADG) from d 7 to 14 (P = 0.044; 347.9, 378.8, and 396.8 g/d for 0, 3, and 6% frass, respectively), and tended to linearly increase ADG during Phase 1 (P = 0.079; 265.1, 284.8, and 298.6 g/d). No differences were observed for final body weight (P ≥ 0.146; 29.90, 31.48, and 30.70 kg for 0, 3, and 6% frass, respectively), and overall ADG, average daily feed intake (ADFI), or gain to feed ratio (G:F). Diarrhea scores increased (P < 0.001) from d 4 (2.96) to d 7 (4.20) and then decreased (P < 0.001) on d 14 (3.69). Inclusion of frass at 6% had a decreased diarrhea score compared with 3% frass on d 7 (P = 0.029), but pigs fed 6% frass had a greater diarrhea score (P = 0.038) than pigs fed the control diet on d 14. However, scores were indicative of diarrhea for all treatments on d 7 and 14. Serum concentrations of total protein, albumin, globulin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, γ-glutamyltranspeptidase, urea N, creatinine, glucose, Ca, P, Mg, K, Na, Cl, triglycerides, amylase, cholesterol, and creatine phosphokinase measured on d 42 were not different (P > 0.093) between treatments. All serological analytical results were generally within normal expected ranges. In conclusion, these findings suggest that dietary inclusion of frass may improve growth performance of nursery pigs, especially during the early stages of the nursery period.}, journal={Journal of Animal Science}, author={Rubio, Sarah and Kuneff, Izadora Batista and Soler, Fernando and Espinosa, Charmaine and Koutsos, Liz and Heugten, Eric}, year={2024}, month={May} }