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Arlington, MA, United States

Zhang Q.,Purdue University | Xu L.,Purdue University | Doster A.,Maple Leaf Farms | Murdoch R.,Maple Leaf Farms | And 3 more authors.
Poultry Science | Year: 2014

A study was conducted to establish the dietary Thr requirement of Pekin ducks from 15 to 35 d of age. Experimental diets were formulated to contain 0.55, 0.60, 0.65, 0.75, and 0.85% Thr (0.57, 0.60, 0.64, 0.72, and 0.80% on an analyzed basis) and were studied in 2 experiments. In experiment 1, each diet was fed to 10 pens of 52 drakes per pen. Samples were collected at d 35 for determinations of carcass yields, serum immune parameters, and intestinal characteristics. Experiment 2 was a digestibility study, wherein 0.5% chromic oxide was mixed into the experimental diets and fed from 15 to 19 d. Ileal digesta were collected at d 19 to analyze mucin secretions and apparent ileal Thr digestibility. The results showed that feeding 0.72% versus 0.64% Thr improved 15 to 35 d BW gain by 55 g (P < 0.05), reduced feed-to-gain by 0.04 (P < 0.05), as well as increased carcass and breast meat yields by 22 and 24 g, respectively. Also, 0.72% Thr had the highest crude mucin secretion on a DM intake (DMI) basis (P < 0.05), although Thr had no effect on villus height, crypt depth, goblet cells, and MUC2 gene expression in the jejunum and ileum. In addition, serum natural IgY linearly increased (P < 0.0001) with dietary Thr increase. Using nonlinear regressions, Thr requirement was estimated to range from a low of 0.70% to maximize dry crude mucin secretion on a DMI basis to a high of 0.80% to maximize carcass weight and serum IgY production by the linear or quadratic regression. Equivalently, Thr requirement varied between a low of 0.62% to minimize mortality and a high of 0.73% to maximize dry crude mucin secretion expressed as DMI using the quadratic broken-line model. Correspondingly, the apparent ileal digestible Thr requirements were estimated to be 0.52 to 0.66% (0.70 to 0.80% dietary Thr) by quadratic and 0.47 to 0.56% (0.62 to 0.73% dietary Thr) by quadratic broken-line model. © 2014 Poultry Science Association Inc. Source

Chen X.,Purdue University | Horn N.,JBS Inc | Cotter P.F.,Cotter Laboratory | Applegate T.J.,Purdue University
Poultry Science | Year: 2014

A 14-d study was conducted to evaluate the effects of cultured aflatoxin B1 (AFB1) on performance, serum biochemistry, serum natural antibody and complement activity, and hepatic gene expression parameters in Pekin ducklings. A total of 144 male Pekin ducklings were weighed, tagged, and randomly allotted to 4 dietary treatments containing 4 concentrations of AFB1 (0, 0.11, 0.14, and 0.21 mg/kg) from 0 to 14 d of age (6 cages per diet; 6 ducklings per cage). Compared with the control group, there was a 10.9, 31.7, and 47.4% (P < 0.05) decrease in cumulative BW gain with 0.11, 0.14, and 0.21 mg of AFB1/kg of diet, respectively, but feed efficiency was not affected. Increasing concentrations of AFB1 reduced cumulative BW gain and feed intake both linearly and quadratically, and regression equations were developed with r2 ≥0.73. Feeding 0.11 to 0.21 mg of AFB1/kg reduced serum glucose, creatinine, albumin, total protein, globulin, Ca, P, and creatine phosphokinase linearly, whereas serum urea N, Cl, alkaline phosphatase, and aspartate amino transferase concentrations increased linearly with increasing AFB1 (P < 0.05). Additionally, 0.11 to 0.21 mg of AFB1/kg diets impaired classical and alternative complement pathways in the duckling serum when tested by lysis of rabbit, human type O, and horse erythrocytes, and decreased rabbit and horse agglutinins (P < 0.05). Liver peroxisome proliferator activated receptor α (PPARα) expression was linearly downregulated by AFB1 (P < 0.01). Results from this study indicate that for every 0.10 mg/kg increase in dietary AFB1, cumulative feed intake and BW gain decrease approximately 230 and 169 g per duckling from hatch to 14 d; and that AFB 1 at very low concentrations can significantly impair liver function and gene expression, and innate immune dynamics in Pekin ducklings. © 2014 Poultry Science Association Inc. Source

Zhang Q.,Purdue University | Zeng Q.F.,Purdue University | Zeng Q.F.,Sichuan Agricultural University | Cotter P.,Cotter Laboratory | Applegate T.J.,Purdue University
Poultry Science | Year: 2016

Two experiments were conducted to determine the dietary threonine (Thr) requirement of Pekin ducks from hatch to 14 d of age. In experiment 1, practical corn-soybean meal diets were formulated to contain 0.78, 0.84, 0.90, 0.96, and 1.02% Thr (0.74, 0.83, 0.88, 0.92, and 1.00% Thr on an analyzed basis). In experiment 2, corn-soybean meal diets supplemented with 11 crystalline amino acids were formulated to contain 0.60, 0.70, 0.80, 0.90, 1.00, and 1.10% Thr (0.60, 0.75, 0.89, 0.95, 1.01, and 1.09% Thr on an analyzed basis). In both experiments, diets were fed to 8 replicate cages with 6 male ducks per cage. Body weight and feed intake from each cage were recorded weekly. At 14 d of age, breast meat, ileal digesta, and serum were collected to determine breast meat yield, mucin secretion, and serology parameters. In both studies, the estimated Thr requirement (expressed as % dietary Thr basis) for 14 d BW and BW gain (BWG) by quadratic broken-line (QBL) regression were similar, which were 0.87 and 0.86%, respectively. Additional measures in both experiments resulted in Thr requirements via QBL regression in rank order of crude mucin secretion < breast meat yield < serum immune activity. Summing up the estimates from both studies, the Thr requirement ranged from a low of 0.81% to maximize feed intake (FI) to a high of 1.00% to maximize serum Rb L100 by QBL regression. Correspondingly, the Thr requirement varied between a low of 0.90% to maximize crude mucin secretion on a dry matter intake (DMI) basis and a high of 0.98% to maximize feed-to-gain when using quadratic regression. © 2016 Poultry Science Association Inc. Source

Cotter P.F.,Cotter Laboratory
Poultry Science | Year: 2015

Atypical plasmacytes having distinctive cytoplasmic vacuoles (Mott cells) were detected in 77/1,000 (7.7%) of commercial hens housed conventionally, in aviaries, or in enriched environments. The earliest Mott positive peripheral blood samples were at placement (18 wk) from 2 consecutive commercial flocks. Additional samples obtained at 32, 48, 56, and 77 wk were positive. Most Mott cells came from hens with high total white blood cell counts as a component of leukocytosis. However, Mott cells were found in hens with low total white blood cell counts, and low heterophil/lymphocyte ratios. Phagocytosis of bacteria by some Mott cells was a remarkable feature. Many of the Mott positive hens had polymicrobial bacteremia and a few had fungemia likely accounting for the leukocytosis. In other cases, free-swimming bacteria were located near to a Mott cell. These atypical cells were in the peripheral blood samples from other poultry; a tom at slaughter (17 wk), experimental toms (10 wk), and experimental ducklings. Examples are included. As descriptions of avian Mott cells are few, the purpose of describing these cells is their contribution to hematology, immunology, and cytology. Mott cells like other atypia are sentinels, frank cytological indicators of an unusual hemogram, and consequently infer stress. Therefore, they bear directly on welfare issues. © 2015 Poultry Science Association Inc. Source

Cotter P.F.,Cotter Laboratory
Poultry Science | Year: 2015

Lymphocytes comprise a family of cells descended from bursa and thymus progenitors whose differentiation is not possible by standard hematology. However, if they are small with a nuclear/cytoplasmic ratio near 1, they are "resting" at least in the microscopic sense. Activation, increases their size, and decreases the nuclear:cytoplasmic (N:C) ratio. Reactive cells are infrequent in healthy animal blood. Their presence indicates an immune response in progress, inflammation, stress, or other pathology. Here the purpose is to describe unusual leukocytes and lymphocytes found in the periphery of commercial hens. Samples of Wright stained blood films obtained from commercial hens housed in modern cages are the data source. Photomicroscopy used an Olympus CX41 light microscope equipped with an Infinity-2 1.4 megapixel charge-coupled device (CCD) Universal Serial Bus (USB) 2.0 camera, at 100× (oil) magnification. Collectively these cells illustrate a continuum between mildly "reactive" to grossly "atypical" states. The description begins with normal resting cells, proceeds to mildly atypical, and concludes with grossly abnormal cells. Bone marrow cells, a source of plasmacytes, are included for comparison. Examples of circulating plasmacytes, large plasmacytoid lymphocytes (LPL), foam cells, and cells expressing properties of more than one lineage are included. The importance of these observations lies in their contribution to cytology, hematology, and immunology. Last, because of the wide use of heterophil:lymphocyte ratios (H:L) as a stress measure they bear directly the welfare issues of caged animals. When cells similar to the types described here are in blood, they indicate stress independent of H:L or other standard measures. © 2015 Poultry Science Association Inc. Source

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