Journal Articles
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Item High steam-conditioning temperature during the pelleting process impairs growth performance and nutrient utilization in broiler starters fed barley-based diets, regardless of carbohydrase supplementation(Elsevier Inc. on behalf of Poultry Science Association Inc., 2021-08) Perera WNU; Abdollahi MR; Zaefarian F; Wester TJ; Ravindran VThe influence of supplemental carbohydrase (Carb) and conditioning temperature (CT) on growth performance, nutrient utilization and intestinal morphometry of broilers (d 1–21) fed barley-based diets was examined in a 2 × 3 factorial arrangement, evaluating 2 levels of Carb (0 and 150 g/tonne of feed) and three CT (60, 74, and 88°C). A total of 288, 1-day-old male broilers (8 birds/cage; 6 cages/treatment) were used. The activities of endo-1,4-β- glucanase, endo-1,3 (4)-β-glucanase and endo-1,4-β-xylanase in the Carb were 800 BGU/g, 700 BGU/g and 2,700 XU/g, respectively. On d 21, ileal digesta was collected for the determination of nutrient digestibility. There was no significant interaction between Carb and CT for any tested parameter. Supplemental Carb, regardless of CT, increased weight gain (WG; P < 0.05) and reduced feed per gain (F/G; P < 0.001) by 30 g/bird and 6.5 points, respectively. Increasing CT to 88°C reduced (P < 0.05) WG, but increased (P < 0.05) F/G compared to the diets conditioned at 60° and 74°C. Regardless of CT, Carb enhanced (P < 0.05) the digestibility of starch and AMEn by 1.15% and 32 kcal/kg, respectively. Compared to the diets conditioned at 60° and 74°C, CT at 88°C reduced (P < 0.05) digestibility of dry matter, nitrogen, phosphorus, gross energy, and AMEn. Birds fed diets conditioned at 88°C showed lower (P < 0.05) starch digestibility compared to those fed diets conditioned at 60°C. Conditioning at 88°C increased (P < 0.05) jejunal digesta viscosity by 10.2% compared to diets conditioned at 60° and 74°C. Overall, Carb supplementation improved WG, F/G, starch digestibility and AMEn in broilers fed barley-based diets, irrespective of CT applied. Conditioning barley-based diets at 88°C impaired the ability of birds to utilize nitrogen, starch, phosphorus and energy, and consequently deteriorated WG and F/G. The lack of significant interactions between Carb and CT indicated that negative impacts caused by high CT on bird performance and nutrient utilization occurred regardless of Carb enzyme supplementation. Supplemental Carb per se could not remedy the adverse effects of high CT.Item Influence of age and dietary cellulose levels on ileal endogenous energy losses in broiler chickens(Elsevier Inc. on behalf of Poultry Science Association Inc., 2022-07) Khalil MM; Abdollahi MR; Zaefarian F; Chrystal PV; Ravindran VTwo experiments were conducted to investigate the influence of age and dietary cellulose levels on the ileal endogenous energy losses (IEEL) in broiler chickens. In experiment 1, a glucose-based purified diet was used to determine the IEEL. Titanium dioxide (5.0 g/kg) was added to the diet as an indigestible marker. Six groups of broiler chickens aged 1 to 7, 8 to 14, 15 to 21, 22 to 28, 29 to 35 or 36 to 42 d posthatch, were utilized. With the exception of 1-7 d, the birds were fed a starter (d 1–21) and/or a finisher (d 22–35) diet before the experimental diet was introduced. The diet was randomly allocated to 6 replicate cages, and the number of birds per cage was 12 (d 1–7), 10 (d 8–14), and 8 (d 15–42). The ileal digesta were collected at the last day of each week (d 7, 14, 21, 28, 35, and 42). Bird age had no effect (P > 0.05) on the IEEL estimates. The IEEL estimates ranged from 263 to 316 kcal/kg dry matter intake (DMI) during weeks 1 to 6. In Experiment 2, 4 glucose-based purified diets were developed using 0, 25, 50 and 75 g/kg cellulose. Titanium dioxide (5.0 g/kg) was added to the diets as an indigestible marker. The diets were randomly allocated to 6 replicate cages (8 birds per cage) and fed from 18 to 21 d posthatch and, ileal digesta were collected on d 21. The IEEL estimates of broiler chickens at 21 d of age showed a quadratic response (P < 0.05) to increasing cellulose contents. The lowest IEEL (88 kcal/kg DMI) was recorded for the diet without cellulose and the highest IEEL (430 kcal/kg DMI) was observed for the diet with 75 g/kg cellulose. Overall, the present findings confirmed that the IEEL in broiler chickens can be quantified by feeding a glucose-based purified diet. Broiler age had no influence on the IEEL estimates. The IEEL increased with increasing dietary cellulose contents and the IEEL determined using a purified diet without cellulose represents a better estimate of IEEL.Item Apparent metabolizable energy of cereal grains for broiler chickens is influenced by age(Elsevier Inc. on behalf of Poultry Science Association Inc., 2021-09) Khalil MM; Abdollahi MR; Zaefarian F; Chrystal PV; Ravindran VThe current study was conducted to investigate the influence of broiler age on the AME and AMEn of 4 common cereal grains (wheat, sorghum, barley, and corn). Four experimental diets with the same inclusion (962 g/kg) of each grain were developed and fed to groups of broiler chickens aged 1 to 7, 8 to 14, 15 to 21, 22 to 28, 29 to 35, or 36 to 42 d post-hatch. Each diet, in pellet form, was randomly allocated to 6 replicate cages in each age group. Except for the 0 to 7 d age group, the birds were fed a starter (d 0–21) and/or a finisher (d 21–35) diet before the introduction of experimental diets. The number of birds per cage were 10 (d 1–7) and 8 (d 8–42). Excreta were collected over the last 4 d of each age period. The AME and AMEn of the grains were determined by the total excreta collection. Bird age influenced (P < 0.001) the AME and AMEn of all cereal grains. The AMEn of wheat declined quadratically (P < 0.01) with advancing age, from 3,461 kcal/kg in wk 1 to 3,219 kcal/kg in wk 2 and then plateaued. The AMEn of sorghum grain declined linearly (P < 0.001) with advancing age, from 3,762 kcal/kg in wk 1 to 3,614 kcal/kg in wk 2, plateaued to wk 5 and then declined to 3,556 kcal/kg in wk 6. A quadratic (P < 0.001) reduction in the AMEn of barley was observed as birds grew older, with the AMEn decreasing between wk 1 (3,286 kcal/kg) and wk 2 (2,988 kcal/kg), increasing in wk 3 (3,117 kcal/kg) and then plateauing. The AMEn of corn declined quadratically (P < 0.05) with advancing broiler age; the highest AMEn was observed in wk 1 and 5, the lowest AMEn in wk 2, with the other weeks being intermediate. In conclusion, the present results showed that broiler age has a substantial impact on the AME and AMEn of cereal grains and the effect varied depending on the cereal grain. These data suggest that age dependent AME and AMEn values may need to be considered when formulating broiler diets to improve the precision of feed formulation and production efficiency.Item Metabolizable energy and standardized ileal amino acid digestibility of full-fat soybeans for broilers are influenced by wet-heating, expansion temperature, and autoclaving time(Elsevier Inc. on behalf of Poultry Science Association Inc, 2022-09) Abdollahi MR; Wiltafsky-Martin M; Zaefarian F; Ravindran VThe influence of wet-heating (WH) and expansion temperature (ET), and autoclaving time (AT) on the nitrogen-corrected apparent metabolizable energy (AMEn) and standardized ileal digestibility (SID) of AA in full-fat soybeans (FFSB) for broilers was examined in 2 experiments. The AMEn and SID AA of FFSB were determined by the difference and direct methods, respectively. In Experiment 1, raw FFSB (K0) were either treated by WH at 80°C for 1 min and expanded at 115°C (K1-115) or 125°C (K1-125), WH at 100°C for 6 min and expanded at 115°C (K2-115) or 125°C (K2-125), or WH at 100°C for 16 min and expanded at 115°C (K3-115) or 125°C (K3-125). Wet-heating and ET significantly (P < 0.001) increased the AMEn in FFSB. Among heat-treated FFSB, K1-115 and K1-125 resulted in the lowest and highest AMEn values, respectively, with all samples wet-heated at 100°C being intermediate. The K3-125 had AMEn values similar (P > 0.05) to K1-125. Among heat-treated FFSB, the highest average SID AA was recorded for K3-125. In Experiment 2, K3-125 from experiment 1 was divided into 9 batches and autoclaved at 110°C for 15 (Z1), 30 (Z2), 45 (Z3), 60 (Z4), 120 (Z5), 180 (Z6), 240 (Z7), 300 (Z8), and 360 (Z9) min. A quadratic (P < 0.01) pattern was observed for the effects of AT on AMEn. The AMEn was unaffected until 300 min AT and then declined at 360 min. The AT quadratically (P < 0.001) affected the average SID AA where the SID increased from K3-125 to Z1, plateaued to Z5, and then declined to Z9. In conclusion, the results demonstrated that WH at 100°C for 16 min followed by expansion at 125°C as the most optimal wet-heating and expansion processing, associated with the highest SID AA. Autoclaving at 110°C for 30 min enhanced energy utilization and AA digestibility in FFSB, suggesting that further advantages may be achieved by short-time autoclaving of previously wet-heated and expanded FFSB samples.Item Basal ileal endogenous amino acid flow in broiler chickens as influenced by age(Elsevier Inc, 2021-08) Barua M; Abdollahi MR; Zaefarian F; Wester TJ; Girish CK; Chrystal PV; Ravindran VThe current study was carried out to measure the basal ileal endogenous amino acid (EAA) flow in male broilers (Ross 308) at different ages (d 7, 14, 21, 28, 35, and 42), following the feeding of a nitrogen-free diet. Titanium dioxide (5 g/kg) was included as an indigestible marker. The nitrogen-free diet was offered for four days prior to ileal digesta collection to 6 replicate cages housing 14 (d 3–7), 12 (d 10–14), 10 (d 17–21), 8 (d 24–28), 8 (d 31–35), and 6 (d 38–42) birds per cage. The basal EAA flow was calculated as g/kg DM intake. The amino acid (AA) profile of endogenous protein, expressed as g/100 g protein, was also calculated. The basal endogenous flow of nitrogen and all individual and total AA decreased quadratically (P < 0.05 to 0.001), with flows being higher on d 7, then decreasing on d 14, plateauing until d 35 and decreasing further on d 42. The concentrations of Trp, Cys, and Gly in the endogenous protein increased linearly (P < 0.01 to 0.001) with advancing age, whereas a linear decrease (P < 0.001) was noted for Lys. A quadratic influence (P < 0.05 to 0.001) was observed for the concentrations of Ile, Leu, Met, Val, and Asp. These changes in the endogenous protein profile may be attributed to variations in the contribution of endogenous sources with age but delineating the exact contribution of different sources is complicated. Overall, the current findings suggest that the basal ileal EAA flow is influenced by broiler age and age-specific EAA flows may need to be considered to standardize the AA digestibility.