Bobeck, Elizabeth

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eabobeck@iastate.edu
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Bobeck
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Mitochondrial and Glycolytic Capacity of Peripheral Blood Mononuclear Cells Isolated From Diverse Poultry Genetic Lines: Optimization and Assessment

2022-01-28 , Lamont, Susan , Bobeck, Elizabeth , Bobeck, Elizabeth A. , Animal Science

Cellular metabolic preference is a culmination of environment, nutrition, genetics, and individual variation in poultry. The Seahorse XFe24 analyzer was used to generate foundational immune cellular metabolic data in layer, broiler, and legacy genetic strains using fresh chicken peripheral blood mononuclear cells (PBMCs). Baseline mitochondrial respiration [oxygen consumption rate (OCR)] and glycolytic activity [extracellular acidification rate (ECAR)] were determined in modern commercial laying hen (Bovans White) and broiler (Ross 308) lines, as well as the highly inbred lines of Iowa State University (L8, Fayoumi M-15.2, Spanish, Ghs-6), partially inbred broiler line, and advanced intercrosses of broiler by Fayoumi M-15.2 and broiler by Leghorn lines. Commercial broiler vs. Bovans layer and unvaccinated vs. vaccinated Bovans layer immune cell metabolic potential were compared following an in-assay pathway inhibitor challenge. Titrations consistently showed that optimal PBMC density in laying hens and broilers was 3 million cells per well monolayer. Assay media substrate titrations identified 25 mM glucose, 1 mM glutamine, and 1 mM sodium pyruvate as the optimal concentration for layer PBMCs. Pathway inhibitor injection titrations in Bovans layers and broilers showed that 0.5 μM carbonyl cyanide-4 phenylhydrazone (FCCP) and 1 μM oligomycin were optimal. Baseline OCR and ECAR were significantly affected by genetic line of bird (p < 0.05), with the dual-purpose, L8 inbred line showing the highest OCR (mean 680 pmol/min) and the partially inbred broiler line showing the greatest ECAR (mean 74 mpH/min). ECAR metabolic potential tended to be greater in modern layers than broilers (p < 0.10), indicating increased ability to utilize the glycolytic pathway to produce energy. OCR was significantly higher in vaccinated than unvaccinated hens (p < 0.05), while baseline ECAR values were significantly lower in vaccinated Bovans laying hens, showing increased oxidative capacity in activated immune cells. These baseline data indicate that different genetic strains of birds utilized the mitochondrial respiration pathway differently and that modern commercial lines may have reduced immune cell metabolic capacity compared with legacy lines due to intense selection for production traits. Furthermore, the Seahorse assay demonstrated the ability to detect differences in cellular metabolism between genetic lines and immune status of chickens.

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Laser Environmental Enrichment and Spirulina Algae Improve Broiler Growth Performance and Alter Myogenic Gene Expression and pectoralis major Dimensions

2021-12-14 , Johnson, Anna , Bobeck, Elizabeth , Bobeck, Elizabeth A. , Animal Science

Sustainability in poultry production is evident in efforts to reduce inputs and a focus on bird welfare and livability. Dietary protein alternatives to traditional sources such as soybean meal aim to meet or exceed efficiency benchmarks and be cost-effective. Environmental enrichment encouraging activity may reduce the occurrence of the predominant breast muscle myopathy, woody breast (WB); interventions to minimize muscle damage and economic loss have yet to be established. The study objectives were to maintain or improve broiler performance and breast quality through environmental enrichment and partially replacing dietary soybean meal with Spirulina. Twelve hundred Ross 708 broilers were randomly assigned to enrichment (LASER; laser enrichment, or CON; no laser enrichment) and diet (algae; 2.5% Spirulina algae, or control) in a 2 × 2 factorial design for 49 days. The same 70 randomly selected birds were examined for contact dermatitis wk 1–6. Breast width was measured weekly on 200 growing broilers beginning on d22. On d42 and 49 slaughter, WB score was assigned using a tactile 0–3 scale and the right breast filet was weighed (n = 200). RNA isolated from 30 breast muscle samples each at d42 and 49 was analyzed using real-time qPCR. Laser enrichment increased body weight at all timepoints (d49: 0.148 kg, P < 0.001). Feed conversion ratio was improved in LASER-enriched birds by 3 points in the starter period (P = 0.003). Breast width was increased at all timepoints in LASER-enriched birds compared to CON (d49: 0.47 cm, P < 0.001). Algae inclusion increased body weight at d28 (0.059 kg, P = 0.005). At d42, 12% more LASER-enriched WB scores were 0 (normal) compared to CON, and at d49, 15% more enriched scores were 0. At d42, 5% more algae-fed broiler scores were 0 compared to control. LASER-enriched broiler breast tissue showed upregulated expression of myogenin, muscle regulatory factor 4, insulin-like growth factor 1, and myostatin compared to CON (P < 0.01). Both laser enrichment and algae inclusion improved broiler performance without negatively impacting environmental or physiological outcomes. LASER enrichment decreased severity of WB score and positively shifted myogenic gene expression in the breast muscle at slaughter.

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Laser Enrichment Device Stimulates Broiler Laser-Following Behavior While Increasing Individual Bird Locomotion and Pen-Wide Movement

2021-11-29 , Johnson, Anna , Bobeck, Elizabeth , Bobeck, Elizabeth A. , Animal Science

Genetic selection for fast growth rate and high breast muscle yield in modern broilers has unintended effects on animal welfare and behavior, namely in terms of inactivity and leg disorders. We hypothesized that exercise stimulated through environmental enrichment could positively stimulate pen-wide activity and improve bird welfare. The study objectives were to implement a laser enrichment device to motivate active and feeding behaviors throughout the pen. Twelve hundred Ross 708 broilers were randomly assigned to enrichment (LASER; laser enrichment, or CON; no laser enrichment) for 49 d. Seventy focal birds were randomly assigned to 14 video-recorded pens for behavioral analysis, including focal bird home pen behavior and walking distance. Pen-wide activity was also measured during the 4-min laser periods, four times daily, d0–8, and 1 day weekly, wk 1–6. Focal birds were gait scored wk 1–6, and were euthanized on d42 for tibia bone mineral content, density, and bone breaking strength analysis. Time spent active was increased in LASER-enriched birds compared to CON on wk 3–5 by up to 214% (wk 4), and percent of time at the feeder was increased in LASER-enriched birds by 761% on wk 4 (P < 0.05). Peak percent of birds following the laser (LASER-enriched pens only) was observed on d0 (8.52%). Over wk 1–6, peak laser-following behavior was observed on wk 3 (3.07% of birds). Percent of birds moving during laser periods was increased in LASER-enriched pens on d0, 1, 2, 6, 7, and 8, with a percent increase of 68.7% observed on d1 (P < 0.05). Percent of birds moving (laser-following or not) was increased on wk 1, 3, and 4 in LASER-enriched pens, with an increase of 69.7% observed on wk 4 (P < 0.05). No differences were found in tibia measures. These data indicate that laser enrichment stimulated voluntary locomotion through wk 5 and laser-following behavior through wk 6, and that the relatively small percent of birds actively following the laser stimulated pen-wide movement above the level of the CON through wk 4 on study.

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