Journal Articles

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Author: search.filters.author.Wester TJSubject: search.filters.subject.Digestibility

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    Potential of field peas and faba beans as protein-rich alternatives for partial or full replacement of soybean meal in broiler chicken diets
    (Elsevier Inc on behalf of Poultry Science Association Inc, 2026-01-01) Sadr VS; Macelline SP; Kim E; Toghyani M; Hamungalu O; Wester TJ; Barekatain R; Liu SY
    This study aimed to evaluate the potential of field peas (FP), faba beans (FB), and their combination to replace soybean meal (SBM) in broiler diets. Experimental diets were formulated to progressively replace SBM with FP, FB, or both across four feeding phases: starter (0–10 d), grower (10–24 d), finisher (24–35 d), and withdrawal (35–42 d). Each of the six dietary treatments was replicated 10 times, with 6 straight-run Ross 308 broiler chicks per replicate. Growth performance was monitored, and nutrient utilization was assessed. Protein and starch digestibility were measured at the distal jejunum and distal ileum, and the starch to protein (S:P) disappearance rate and ratios were calculated for each intestinal segment. Progressive replacement of SBM up to 55 % in the starter, 66 % in the grower, and 100 % in the finisher and withdrawal phases resulted in final BW and FCR that were statistically similar to the control SBM-based diets. However, complete replacement of SBM from the grower phase onward significantly reduced BW, FCR, and breast meat yield, particularly in birds offered diets based on FP (P < 0.05). Dietary treatments had no significant effect on AME, AMEn, or the AME:gross energy ratio (P > 0.05). Diets containing FP, FB, or their combination significantly increased nitrogen retention and excreta dry matter, and reduced water intake (P < 0.05). No significant effects were observed on protein or starch digestibility or their disappearance rates at either the distal jejunum or distal ileum (P > 0.05). However, the inclusion of FP and FB significantly increased the S:P disappearance rate ratio in both intestinal segments (P < 0.05). These results indicate that both FP and FB can be used effectively only for partial replacement of SBM in broiler diets. While the increased S:P disappearance rate ratio suggests altered nutrient absorption dynamics and may explain the decline in performance of the birds fed high level of legumes, further investigation on underlying effects on intestinal functions is required.
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    Effect of age on the standardized ileal amino acid digestibility of soybean meal and canola meal in broilers
    (Elsevier B.V. on behalf of KeAi Communications Co., Ltd., 2023-12-02) Barua M; Abdollahi MR; Zaefarian F; Wester TJ; Girish CK; Chrystal PV; Ravindran V
    Standardized ileal digestibility coefficients (SIDC) of nitrogen (N) and amino acids (AA) in two protein sources (soybean meal [SBM] and canola meal [CM]) were investigated at six broiler ages (d 7, 14, 21, 28, 35, and 42). Two assay diets were formulated to contain either SBM (413 g/kg) or CM (553 g/kg) as the sole dietary AA source. Titanium dioxide (5 g/kg) was added as an indigestible marker. A total of 696 male broilers at 1 d old were allotted to 12 replicate cages per age group. Each assay diet was offered to birds for 4 d prior to the ileal digesta collection on d 7 (14 birds/cage), 14 (12 birds/cage), 21 (10 birds/cage), 28 (8 birds/cage), 35 (8 birds/cage) and 42 (6 birds/cage), respectively. The apparent digestibility coefficients were standardized using age-specific basal endogenous AA flows. In the SBM group, though the SIDC of N tended to be influenced (quadratic; P = 0.075) by age, no linear or quadratic response of age effect was observed on the average SIDC of indispensable (IAA) and total AA (TAA). An age effect (quadratic; P < 0.05) was observed on the average SIDC of dispensable AA (DAA) in SBM with the highest value recorded at d 7, followed by a decrease from d 14 to 28, which increased beyond d 35. The SIDC of some individual AA (Arg, Thr, Trp, Cys, Pro) were affected (P < 0.05 or P < 0.001) in a quadratic manner by age. In the CM, the SIDC of N, average SIDC of IAA, DAA and TAA were influenced (quadratic; P < 0.05 or P < 0.001) by age. The SIDC of N and average SIDC of DAA and TAA were higher from d 7 to 14, declined at d 21, and then increased beyond d 28. The average SIDC of IAA was low between d 7 and 28 and increased thereafter. The SIDC of individual AA were affected (linear or quadratic; P < 0.05 or P < 0.001) by different magnitudes by age. The age influence on the SIDC AA was variable, depending on the protein source and AA. The results demonstrate that age-specific SIDC AA data might need consideration in broiler feed formulations.