VTechWorks Repository :: Browsing by Author "Persia, Michael E."

Browsing by Author "Persia, Michael E."

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The Acute and Chronic Effects of a Cyclic Heat Stress on 24 to 28 Week Old Laying Hens on Performance, Egg Quality, Apparent Metabolizable Energy, and Blood Chemistry
Barrett, Nathaniel W. (Virginia Tech, 2016-11-02)
Commercial laying hens are heavily selected for increased egg production, but little selection has occurred for resistance to extreme temperatures. The objective of the experiment was to determine the effects of a daily cyclic heat stress (HS) on performance, body temperature, egg quality, nitrogen corrected apparent metabolizable energy, and blood chemistry in laying hens at acute and chronic time points. In total, 407 pure line laying hen pullets (18 wk) were sourced from Hy-Line International and housed individually for the duration of the experiment. Feed intake, egg production, and body weights were significantly decreased while egg weight and feed efficiency increased due to HS exposure. All egg quality parameters except yolk weight were decreased by HS exposure, including Haugh unit, eggshell and albumen weights. Egg yolk weights were increased over the first 2 wk of HS before falling. Blood chemistry was affected by HS resulting in respiratory alkalosis likely caused by increased respiration and evaporative cooling. There was a decrease in the PCO2, an increase in pH and a reduction in iCa in the blood within 4 to 6 hours of HS when compared to pre-HS levels. The data indicate that the hens were negatively affected by HS and the response was different for acute and chronic time points. At the acute time point the changes to the hen's physiology were caused by altered blood chemistry, but after chronic exposure, the low feed intake seemed to influence the responses.
Commercial Hy-Line W-36 pullet and laying hen venous blood gas and chemistry profiles utilizing the portable i-STAT (R) 1 analyzer
Schaal, T. P.; Arango, J.; Wolc, A.; Brady, J. V.; Fulton, J. E.; Rubinoff, I.; Ehr, I. J.; Persia, Michael E.; O'Sullivan, Neil P. (Oxford University Press, 2016-02-01)
Venous blood gas and chemistry reference ranges were determined for commercial Hy-Line W-36 pullets and laying hens utilizing the portable i-STAT 1 analyzer and CG8+ cartridges. A total of 632 samples were analyzed from birds between 4 and 110 wk of age. Reference ranges were established for pullets (4 to 15 wk), first cycle laying hens (20 to 68 wk), and second cycle (post molt) laying hens (70 to 110 wk) for the following traits: sodium (Na mmol/L), potassium (K mmol/L), ionized calcium (iCa mmol/L), glucose (Glu mg/dl), hematocrit (Hct% Packed Cell Volume [PCV]), pH, partial pressure carbon dioxide (PCO2 mm Hg), partial pressure oxygen (PO2 mm Hg), total concentration carbon dioxide (TCO2 mmol/L), bicarbonate (HCO3 mmol/L), base excess (BE mmol/L), oxygen saturation (sO2%), and hemoglobin (Hb g/dl). Data were analyzed using ANOVA to investigate the effect of production status as categorized by bird age. Trait relationships were evaluated by linear correlation and their spectral decomposition. All traits differed significantly among pullets and mature laying hens in both first and second lay cycles. Levels for K, iCa, Hct, pH, TCO2, HCO3, BE, sO2 , and Hb differed significantly between first cycle and second cycle laying hens. Many venous blood gas and chemistry parameters were significantly correlated. The first 3 eigenvalues explained ∼2/3 of total variation. The first 2 principal components (PC) explained 51% of the total variation and indicated acid-balance and relationship between blood O2 and CO2. The third PC explained 16% of variation and seems to be related to blood iCa. Establishing reference ranges for pullet and laying hen blood gas and chemistry with the i-STAT 1 handheld unit provides a mechanism to further investigate pullet and layer physiology, evaluate metabolic disturbances, and may potentially serve as a means to select breeder candidates with optimal blood gas or chemistry levels on-farm.
Developmental gene expression of host defense peptides in immune organs and the small intestine of turkey poults (Meleagris gallopavo)
Hamad, Shaimaa Kamal (Virginia Tech, 2016-09-28)
Host defense peptides (HDPs) are a large group of small positively charged peptides that play an important role in innate immunity. Their role is more critical at early ages when other components of the immune system have not fully developed. There are three classes of avian HDPs: avian beta defensins (AvBDs), cathelicidins (Cath) and liver-expressed antimicrobial peptide 2 (LEAP-2). The objective was to compare expression of HDPs in male turkey poults at day of hatch (D0), D7, D14, D21 and D28 from the thymus, spleen, bursa, duodenum, jejunum and ileum. The expression of AvBD1, AvBD2, AvBD8, AvBD9, AvBD10, AvBD13, Cath2, Cath3 and LEAP-2 was measured using qPCR (n=6 birds/tissue/age). Data were analyzed by one-way ANOVA and Tukey's test, and significance considered at P ≤ 0.05. AvBDs and Caths exhibited greater expression in immune organs than intestinal tissues, with the greatest expression of AvBDs observed in the spleen. The intestinal tissues showed very low expression of AvBDs except for AvBD10 at D0. Similar to AvBDs, Caths expression in the immune organs was greater than the intestinal tissues with the spleen having the greatest expression among immune organs. Conversely, LEAP-2 showed greater expression in the intestinal tissues than in the immune tissues, which showed very low LEAP-2 expression unlike other HDPs. Understanding the differential expression of HDPs could reveal the innate immune status of poults, and may subsequently allow improvement of their health through appropriate mitigation strategies.
DNA Sequence and Haplotype Variation Analysis of Inflammatory Response Genes NLRX1, IL6, and IL8 in the Turkey (Meleagris gallopavo)
Russell, Kadijah Lashunte (Virginia Tech, 2019-02-08)
Genotype-phenotype analyses continue to be the primary goal for genome analyses in livestock and poultry breeding. Essential to accomplish this goal is the need to identify variation at the genomic level. To test the hypothesis that DNA sequence variations in inflammatory response genes are associated with phenotypic differences in the heritage turkey, the primary objective of this project was to search for single nucleotide polymorphisms (SNPs) in candidate inflammatory response genes. A minor objective was to develop a system for inducing inflammatory response in the turkey using a microbe-based lipopolysaccharide (LPS), an approach previously described for the chicken. A total of 18 SNPs was identified in the three genes screened in this project: Interleukin 6 (IL6) and 8 (IL8), and NLRX1. Mortality data from the LPS challenge were not significantly different among the strains. Further gene expression analyses will be part of future work. The SNP data represent the first extensive analyses of candidate inflammatory response genes in the turkey. Combined with the protocols developed for inflammation assessment in the turkey the SNPs described here will be valuable resources for future inflammation:genotype evaluation in the turkey
Effect of amino acids and vitamin D3 on performance and biological responses in poultry
Wen, Jinlei (Virginia Tech, 2018-06-08)
As productive performance is improved by breed selection, amino acid requirements may change to support this higher performance in poultry. The first objective of this dissertation was to update the valine and tryptophan requirement of small-framed laying hens and the lysine requirement of young broilers using empirical dose-response methods. The tryptophan requirement was estimated as 155.8 mg/d for egg mass, 153.2 mg/d for egg production and 140.4 mg/d for feed conversion ratio using a linear broken line model. For valine, the requirement was highest for egg mass, 597.3 mg/d, followed by egg production, 591.9 mg/d and feed conversion ratio (FCR), 500.5 mg/d. The lysine requirement of young chicks was estimated by conducting four short term experiments from 1 to 3, 3 to 5, 5 to 8 and 8 to 11 days of age, respectively. The lysine requirement from 1 to 3, 3 to 5 and 5 to 8 days of age were not able to be estimated as no dose response was observed on growth performance most likely due to an overestimation of the lysine requirement. Digestible lysine requirement from 8 to 11 days of age was 1.057%, 1.050% and 1.016% based on body weight gain, FCR and pectoralis major weight using a linear broken line model, respectively. In addition to determining amino acid requirements, research was conducted to develop a new bacterial protein meal for use in laying hens diets. The data suggested that diets containing 7.5% of the bacterial protein meal was able to at least maintain egg production in laying hens, but 15% bacterial protein meal resulted in reduced performance. The second objective of this dissertation was to investigate the effects of various concentrations of dietary vitamin D3 on pullet and laying hen performance, eggshell quality and bone health in laying hens. Pullets/hens were randomly assigned to five dietary treatments containing vitamin D3 from 1,681 to 68,348 IU/kg diet from day of hatch until 68 weeks of age. These data suggested that dietary vitamin D3 fed at 68,348 IU/kg resulted in reduced egg production, but vitamin D from 8,348 to 35,014 IU/kg diet maintained egg production, increased egg vitamin D content in a dose dependent manner, and generally increased both eggshell quality and pullet and hen bone mineral status.
Effect of various concentration of butyric acid on growth performance, intestinal lesion scores, and body composition of broilers raised on used litter
Sizmaz, Ozge O.; Barrett, Nathaniel W.; Lewis, James; Yakout, Hathum; Persia, Michael E. (2022-12-01)
There is still a need for the evaluation of alternative feed additives, including organic acids such as butyric acid, when fed in broiler diets without antibiotic growth promoters. The removal or limitation of growth promoting antibiotics from commercial production changes the opportunities for feed additives in the poultry industry and allows for the evaluation of replacement feed additives that may not have been cost effective when growth promoting antibiotics are available. Therefore, an experiment was conducted to evaluate the effects of various concentrations (200 ppm, 400 ppm, and 800 ppm) of coated butyric acid on growth performance, intestinal lesion score, and body composition of 42-day-old broilers raised on used litter. The addition of the coated butyric acid at 400 ppm and 800 ppm increased BW and 800 ppm improved mortality corrected feed conversion ratio (FCRm) over the 42-d period compared with the negative control (NC) fed broilers. Although performance was improved, the ratio of lean mass to fatty mass in the broilers was unchanged suggesting a generalize growth response. No significant differences were observed in lesion scores in the duodenum and jejunum and overall lesion scores were low. Both 400 and 800 ppm of butyric acid were able to increase 42-d broiler body weight in comparison to the NC fed birds, but 800 ppm of butyric acid was required to also improve the FCRm in comparison to the NC fed birds.
Effects of a direct fed microbial (DFM) on broiler chickens exposed to acute and chronic cyclic heat stress in two consecutive experiments
Sarsour, A.H.; Koltes, D.A.; Kim, E.J.; Persia, Michael E. (Elsevier, 2022)
Two consecutive 35 d experiments were conducted to investigate the effects of a multistrain DFM fed continuously to broiler chickens exposed to HS from 28 to 35 d on broiler performance, body composition, ileal digestibility, and intestinal permeability using serum Fluorescein Isothiocyanate Dextran (FITC-d) concentration. The treatments were arranged as a 2 x 2 factorial with temperature: Elevated (HS: 33 ± 2°C for 6 h and 27.7°C for the remaining 18 h from 28 to 35 days of age) and Thermoneutral (TN: 22 to 24°C over the entire 24-h day from 28 to 35 days of age) and diet: cornsoybean meal based with and without DFM (3-strain Bacillus; Enviva PRO) fed over the entire 35-d period as the two factors. Experimental diets were formulated to meet all nutrient recommendations based on breed standards using a starter (0−10 d), grower (10−21 d), and finisher (21−35 d) period. For each of the 2 experiments, 648 Ross 708 broiler chicks were allotted among the treatments with 9 replicate pens of 18 broilers. Data were analyzed as a 2 × 2 factorial within each experiment in JMP 14. In both experiments, cloacal temperatures were increased (P ≤ 0.05) in the broilers subjected to the HS treatment at both 28 d (acute) and 35 d (chronic). Supplementing birds with DFM reduced cloacal temperatures in the Experiment 1 at 28 d, but not at the other time periods. The HS treatment reduced body weight gain and lean tissue accretion from 0 to 35 d in both experiments (P ≤ 0.05). In Experiment 2, when the litter was reused BWG was increased by 36 g/bird with supplementation of DFM (P ≤ 0.05). Ileal digestibility at 28 d (2 h post HS) was improved with DFM supplementation in both experiments (P ≤ 0.05). Serum FITC-d increased with HS at both 28 and 35 d. Serum FITC-d was generally decreased with DFM at 28 d but the response was inconsistent at 35 d. Overall, the results suggest that HS reduced broiler performance and DFM treatment improved intestinal permeability and nutrient digestibility responses to HS in both experiments but did not improve performance until built up litter was used in Experiment 2.
The Effects of a Single Strain Bacillus subtilis DFM on pullet performance, laying hen performance, and egg quality when fed from day of hatch until 70 weeks
Samper, Jordyn Marie (Virginia Tech, 2022-08-18)
Direct-fed microbials (DFM) are a method to increase bird performance and health when antibiotics are removed or limited in the diet. The objective of this experiment was to determine the effects of a single strain Bacillus subtilis DFM on pullet performance, layer performance, and egg quality when fed from day of hatch until 70 weeks of age. In total, 576 Hy-Line W-36 laying hen pullets were randomly divided between two treatments (Control and DFM) on day of hatch across 12 cages for each of the treatments and maintained on those respective treatments for 70-weeks. The DFM was added at a target dose of 300,000 cfu/kg of feed. At the end of the 17-week pullet phase, DFM fed pullets resulted in reduced feed intake, improved FCRm with both similar body weights (P = 0.98) and body composition (P > 0.05) to the control fed pullets. At 17 weeks, 72 birds were randomly selected from each treatment and moved to 12 laying hen cages. At the end of the 52-week laying hen phase, DFM-fed hens had significantly higher hen-day egg production (P = 0.02), but decreased egg weights. No differences were reported in egg mass or feed intake, but FCR was significantly improved (P = 0.02) on a per dozen eggs basis, and improved (P = 0.06) on a g/g basis by 7.1 points with DFM-fed hens having an FCR of 2.016 and control fed hens having and FCR of 2.087. Supplementation of diets with DFM resulted in a trend in egg specific gravity, but no differences were reported in shell breaking strength or shell weight. Overall, supplementation of the DFM lowered feed intake and improved FCR without affecting body composition in the pullet phase, and increased production and improved FCR during the egg laying phase.
Effects of available phosphorus source and concentration on performance and expression of sodium phosphate type IIb cotransporter, vitamin D-1 alpha-hydroxylase, and vitamin D-24-hydroxylase mRNA in broiler chicks
Omara, Islam I.; Mou, C. T.; Persia, Michael E.; Wong, Eric A. (Elsevier, 2020-04-01)
This experiment was conducted to examine the effect of 2 phosphorus (P) sources on broiler performance to day 14. The P bioavailability was estimated using bird performance and tibia ash measurements, whereas P digestibility, intestinal P transporter, kidney vitamin D-1α-hydroxylase, and vitamin D-24-hydroxylase mRNA abundances were also determined. Slope regression analysis was used to determine the bioavailability of dicalcium phosphate (Dical P) and nanocalcium phosphate (Nano P) with dietary available P (AvP) set to 0.20% P (control) using AvP from the major ingredients and Dical P. The experimental treatments were achieved by supplementation with either Dical P or Nano P to generate 0.24, 0.28, 0.32, and 0.36% AvP. A total of 648-day-old unsexed broiler chicks were divided into 72 birds per treatment (8 replicate cages of 9 birds). Slope regression analysis showed positive linear relationships between BW, feed intake (FI), tibia ash weight (TAW), and tibia ash percentage (TAP) with dietary Dical P and Nano P levels. Comparisons between regression slopes for Dical P and Nano P fed birds were not significantly different for BW, feed intake, tibia ash weight, and tibia ash percentage, indicating similar P bioavailability from Dical P and Nano P. There were interactions between P source and AvP for feed efficiency (FE) and apparent ileal P digestibility (AIPD). Dicalcium phosphate had greater FE than Nano P at 0.28% AvP and greater AIPD than Nano P at 0.24% AvP. The addition of AvP from Dical P and Nano P resulted in reduced sodium phosphate cotransporter mRNA abundance in the duodenum in a dose–dependent response. In the kidney, vitamin D-1α-hydroxylase mRNA abundance was greater at 0.36% Nano P compared with control, but there was no difference with Dical P. There was no difference in vitamin D-24-hydroxylase mRNA abundance between control and supplementation with Nano P or Dical P. In conclusion, Nano P and Dical P had the same bioavailability but had different effects on gene expression.
The effects of Bacillus subtilis, dietary calcium and coccidial vaccines in broilers experiencing naturally occurring necrotic enteritis
Calvert, Alamanda J. (Virginia Tech, 2022-06-03)
Necrotic enteritis (NE) is a disease that negatively affects broiler performance and has increasingly become a problem with the reduced use of antibiotics. There is increased interest to utilize alternative methods including coccidial vaccines and direct fed microbials (DFM) to reduce or prevent NE. Additionally, it has been demonstrated that reduced dietary Ca can reduce NE mortality. The objective of the first study was to examine the effects of Bacillus subtilis (DFM) in combination with attenuated (AV) and non-attenuated (NV) coccidial vaccines in broilers with NE. The objective of the second study was to determine the effects of DFM, antibiotic (BMD) or negative control (NC) with standard dietary Ca (0.9%) or below standard Ca (0.75%, 0.6%) in broilers with NE. To induce a natural NE occurrence, birds were vaccinated with the appropriate coccidial vaccine and then placed on reused litter from a previous flock exhibiting NE lesions and mortality. In the first trial DFM reduced BW and BW gain (P ≤ 0.05) during the starter phase (0 to 14 d). The addition of a DFM in the AV group resulted in decreased (P ≤ 0.05) BW gain and BW at 42 d. The DFM in the NV group resulted in improved (P ≤ 0.05) mortality corrected feed conversion ratio from 0 to 42 d. Overall, with a natural NE occurrence, the effect of DFM was variable depending on what type of coccidial preventative was utilized and was beneficial when used with NV. In the second trial BW and BW gain were increased in broilers fed 0.60% dietary Ca and DFM compared to 0.90% Ca and NC (P ≤ 0.05). Broilers fed 0.60% Ca had reduced NE mortality compared to broilers fed 0.90% Ca (P ≤ 0.05). Reducing dietary Ca to below industry standards was able to lessen the severity of NE though the addition of DFM was needed to improve BW. Overall, with a natural NE occurrence, the DFM was beneficial when used with NV and in diets with 0.6% dietary Ca.
Effects of dietary Ca concentration on the performance of broiler chicks fed various sources of dietary P with and without phytase supplementation
Fritzlen, Cooper (Virginia Tech, 2021)
Two experiments were conducted to determine the effects of high dietary calcium (Ca) on broiler chicks fed low phosphorus (P) diets from either nonphytate (nPP) or phytate P (PP) with or without phytase. The response criteria that were analyzed was bird performance, tibia ash, Ca and P digestibility and duodenal P transporter mRNA abundance. Newly hatched broiler chicks were housed in raised-wire starter batteries (65.8 in2) for 16 d. Each experiment had 12 treatments were replicated 6 times using 8 chicks per cage that resulted in a total of 576 Cobb 500 chicks. Experiment 1 had a 3x2x2 factorial arrangement included 3 P treatments (0.225%nPP, 0.225 + 0.1%P from nPP and 0.225 + 0.1%PP), 2 concentrations of Ca (0.9 vs.1.7%Ca) and either (0 or 1,000 FTU of phytase). Experiment 2 also had a 3x2x2 factorial arrangement but set closer to commercial standards (0.325% nPP, 0.325 + 0.1% P from nPP and 0.325 + 0.1% P from PP), 2 concentrations of Ca (0.9 vs.1.4% Ca) with and without phytase (0 or 1,000 FTU of phytase). Body weight gain (BWG), feed intake, feed conversion and mortality were calculated over the 16d period. On 16d, all remaining chicks were euthanized, and the right tibia was analyzed for tibia ash weight (TAW) in mg/tibia and expressed as a percentage (TAP). All data were analyzed as a 3x2x2 factorial using ANOVA in JMP 14 (P ≤ 0.05). In Experiment 1, the phytase interactions were driving FI, which increased BWG (P ≤ 0.05). However, the phytase interactions did not influence bone mineralization (P ≤ 0.05). So, the diet is potentially more appetizing with phytase supplementation. Calcium x phosphorus interaction was driving bone mineralization, but not influencing BWG or FI (P ≤ 0.05). Additionally, bone mineralization was impacted when additional P was put into high Ca diets (P ≤ 0.05). Phytase upregulated P transporter mRNA abundance in normal Ca diets, but the results were muted in high Ca diets (P ≤ 0.05). Experiment 2 used more practical P and Ca conditions to validate the responses from Experiment 1 with the understanding that the potential responses would be blunted. The addition of phytase improved tibia ash when Ca and P were unbalanced (P ≤ 0.05). High concentrations of Ca lowered BWG and FI, but again the addition of phytase to the diet had a more beneficial effect (P ≤ 0.05). Diets with reduced P had an improved P and Ca digestibility and upregulation of P transporter mRNA abundance (P ≤ 0.05). Also, the addition of phytase improved both P and Ca digestibility and downregulated P transporter mRNA abundance (P ≤ 0.05). Overall, both experiments exhibited that source of P did not influence performance but did influence tibia ash. High calcium had a negative effect on performance and digestibility. However, phytase was able to ameliorate negative impacts of high calcium diets. The multiple interactions of Ca, P and phytase indicate a complex relationship among the three factors that require balancing when looking for optimal conditions commercially, especially to maximize performance and skeletal health while balancing cost and environmental considerations.
Effects of Direct-Fed Microbial Products, Butyrate, and Botanicals on Performance and Health of Broilers Raised on Used Pine Shaving Litter
Lewis, Meredith D. (Virginia Tech, 2018-08-29)
Two experiments were conducted to determine the effects of various alternatives to antibiotics in broilers grown on used litter on performance, intestinal lesion scores, body composition, and cecal volatile fatty acid (VFA) concentrations. The first experiment used a corn-soybean meal based basal diet to generate a negative control (NC) diet (without treatment), a Bacillus licheniformis probiotic containing diet (NC + 0.10% DFM1), and four diets that contained various concentrations of a Bacillus subtilis probiotic (NC + 0.05% DFM2, NC + 0.10% DFM2, NC + 0.20% DFM2, and NC + 0.40% DFM2). Experimental diets were fed to broilers over a 42-day period. Body weight gain (BWG) was depressed from d 0-28 and d 0-42 with supplementation of 0.10% DFM1 and 0.05% DFM2 compared to NC fed birds (P ≤ 0.05), with no differences among the remaining treatments and the NC fed birds (P > 0.05). Feed intake (FI) and mortality corrected feed efficiency (FEm) were not different over the 0-42 day period. No differences in oocyst shedding, lesion scores, body composition or cecal VFA production were observed (P > 0.05). Consistently low lesion scores were indicative of a mild coccidial challenge. The second experiment utilized a corn-soybean meal basal diet to generate experimental treatment diets. The basal diet without additional supplements was fed to two groups of control birds, one on clean pine shaving litter (PC) and a second on used litter (NC). Treatment groups were fed the same diet, supplemented with butyrate for the first 14 days (NC + But 0-14), botanicals from d 15-43 (NC + Bot 15-43), butyrate from d 0-14 and botanicals from d 15-43 (NC + But 1-14/Bot 15-43), and butyrate from d 0-43 (NC + But 1-43). Butyrate supplementation reduced BWG from d 0-14 (P ≤ 0.05), but there were no differences in BWG from 0-43 d (P > 0.05). Feed intake was reduced for the NC + But 0-14 group from d 0-43 in comparison to both PC and NC. Lesion scores in the jejunum were reduced with supplementation of butyrate alone, fed for either d 0-14 or d 0-43 (P ≤ 0.05) and is an indication of a mild coccidial infection due to the used litter. Although there were no significant differences among treatments, overall performance was above industry expectations, likely due to the mild fall weather. These two experiments indicate that there are numerous factors involved in the efficacy of antibiotic alternatives, at least partially explaining the inconsistent results observed in the published literature.
Effects of Housing System on Anxiety, Chronic Stress, Fear, and Immune Function in Bovan Brown Laying Hens
Campbell, Andrew M.; Johnson, Alexa M.; Persia, Michael E.; Jacobs, Leonie (MDPI, 2022-07-14)
The scientific community needs objective measures to appropriately assess animal welfare. The study objective was to assess the impact of housing system on novel physiological and behavioral measurements of animal welfare for laying hens, including secretory and plasma Immunoglobulin (IgA; immune function), feather corticosterone (chronic stress), and attention bias testing (ABT; anxiety), in addition to the well-validated tonic immobility test (TI; fearfulness). To test this, 184 Bovan brown hens were housed in 28 conventional cages (3 birds/cage) and 4 enriched pens (25 birds/pen). Feces, blood, and feathers were collected 4 times between week 22 and 43 to quantify secretory and plasma IgA and feather corticosterone concentrations. TI tests and ABT were performed once. Hens that were from cages tended to show longer TI, had increased feather corticosterone, and decreased secretory IgA at 22 weeks of age. The caged hens fed quicker, and more hens fed during the ABT compared to the penned hens. Hens that were in conventional cages showed somewhat poorer welfare outcomes than the hens in enriched pens, as indicated by increased chronic stress, decreased immune function at 22 weeks of age but no other ages, somewhat increased fear, but reduced anxiety. Overall, these novel markers show some appropriate contrast between housing treatments and may be useful in an animal welfare assessment context for laying hens. More research is needed to confirm these findings.
Effects of Nutritional Manipulation on Poultry under Normal and Stressful Conditions
Sarsour, Albaraa Hisham (Virginia Tech, 2021-11-01)
Genetic selection for improved performance has necessitated the frequent update of amino acid requirements to support this improvement. The first objective of this dissertation was to investigate the tryptophan requirement of laying hens in peak production and the lysine and sulfur amino acid requirements of broiler chicks under a phase feeding scenario using different models. Digestible tryptophan requirements were estimated to be 137 for egg production, 133 for egg mass, and 133 for feed efficiency using the linear broken-line model. The lysine and sulfur amino acid requirement were estimated by conducting 3 experiments within the starter phase from 2 to 5, 5 to 8, and 8 to 11 days of age. The linear broken line estimate for digestible lysine was 1.22, 1.17 and 1.16% for BWG and 1.31, 1.21, and 1.14% for FCR in experiments 1, 2, and 3, respectively. The linear broken line estimate for sulfur amino acids was 0.82, 0.81 and 0.94% for BWG and 0.82, 0.80, and 0.90 for FCR in experiments 4, 5, and 6, respectively. The lysine requirements decreased from 2 to 5 to 8 to 11 days, however the sulfur amino acid requirements increased during that same period. This could be due to other roles that sulfur amino acids play in the body other than growth. The second objective of this dissertation was to investigate the effects of a direct fed microbial (DFM) on broilers exposed to a cyclic heat stress in 2 consecutive experiments. In this experiment, the heat stress treatment reduced body weight gain and lean tissue accretion from 0 to 35 d in both experiments. In Experiment 2, when the litter was reused BWG was increased by 36 g/bird with supplementation of DFM. Ileal digestibility at 28 d (2 hr post HS) was improved with DFM supplementation in both experiments. Serum FITC-d increased with HS at both 28 and 35 d. Serum FITC-d was generally decreased with DFM at 28 d but the response was inconsistent at 35 d. Overall, the results suggest that HS reduced broiler performance and DFM treatment improved intestinal permeability and nutrient digestibility responses to HS in both experiments but did not improve performance until built up litter was used in Experiment 2. The last objective of this dissertation was to investigate the effects of sulfur amino acids (SAA) on broilers exposed to a cyclic heat stress. As expected, HS reduced BWG and worsened FCR. The supplementation of SAA had no effect on live performance. At 28 d of age, supplementation of SAA to birds exposed to HS resulted in reduced intestinal permeability. The interaction was lost at 31 d, but HS still increased intestinal permeability (P ≤ 0.05). Potential oxidative damage was reduced by increased SAA supplementation as indicated by an increase in the reduced glutathione to oxidized glutathione ratio. These data suggest that intestinal permeability is compromised acutely to at least three days of heat exposure before the bird can adjust, but oxidative damage is more chronic building over the entire 7 d HS period. SAA might have some protective effect on both intestinal permeability and oxidative stress responses to HS.
Effects of Protease, Phytase and a Bacillus sp. Direct-Fed Microbial on Nutrient and Energy Digestibility, Ileal Brush Border Digestive Enzyme Activity and Cecal Short-Chain Fatty Acid Concentration in Broiler Chickens
Murugesan, Ganapathi R.; Romero, Luis F.; Persia, Michael E. (PLOS, 2014-07-11)
Two experiments were conducted to determine the effects of protease and phytase (PP) and a Bacillus sp. direct-fed microbial (DFM) on dietary energy and nutrient utilization in broiler chickens. In the first experiment, Ross 308 broiler chicks were fed diets supplemented with PP and DFM in a 2×2 factorial arrangement. The 4 diets (control (CON), CON + PP, CON + DFM, and CON + PP + DFM) were fed from 15–21 days of age. In Experiment 1, significant interaction (P≤0.01) between PP and DFM on the apparent ileal digestibility coefficient for starch, crude protein, and amino acid indicated that both additives increased the digestibility. Both additives increased the nitrogen retention coefficient with a significant interaction (P≤0.01). Although no interaction was observed, significant main effects (P≤0.01) for nitrogen-corrected apparent ME (AMEn) for PP or DFM indicated an additive response. In a follow-up experiment, Ross 308 broiler chicks were fed the same experimental diets from 1–21 days of age. Activities of ileal brush border maltase, sucrase, and L-alanine aminopeptidase were increased (P≤0.01) by PP addition, while a trend (P = 0.07) for increased sucrase activity was observed in chickens fed DFM, in Experiment 2. The proportion of cecal butyrate was increased (P≤0.01) by DFM addition. Increased nutrient utilization and nitrogen retention appear to involve separate but complementary mechanisms for PP and DFM, however AMEn responses appear to have separate and additive mechanisms.
Effects of sulfur amino acid supplementation on broiler chickens exposed to acute and chronic cyclic heat stress
Sarsour, A.H.; Persia, Michael E. (Elsevier, 2022)
Chronic heat stress can result in oxidative damage from increased reactive oxygen species. One proposed method to alleviate the chronic effects of HS is the supplementation of sulfur amino acids (SAA) which can be metabolized to glutathione, an important antioxidant. Therefore, the objective of this experiment was to determine the effects of dietary SAA content on broiler chickens exposed to HS from 28 to 35 d on broiler performance, body temperature, intestinal permeability, and oxidative status. Four experimental treatments were arranged as a 2 x 2 factorial consisting of HS (6 h at 33.3°C followed by 18 h at 27.8°C from 28 to 35 d of age) and Thermoneutral (TN- 22.2°C continuously from 28 to 35 d) and 2 dietary concentrations of SAA formulated at 100% (0.95, 0.87, and 0.80% for starter, grower, and finisher diets) or 130% SAA (1.24, 1.13, and 1.04% for starter, grower, and finisher diets). A total of 648-dayold, male Ross 708 chicks were placed in 36 pens with 18 chicks/pen and 9 replicates per treatment. Data were analyzed as a 2 £ 2 factorial in JMP 14 (P ≤ 0.05). No interaction effects were observed on broiler live performance (P > 0.05). As expected, HS reduced BWG by 92 g and increased FCR by 11 points from 28 to 35 d of age compared to TN, respectively (P ≤ 0.05). The supplementation of SAA had no effect on live performance (P > 0.05). Cloacal temperatures were increased by 1.7, 1.4, and 1.2°C with HS at 28, 31, and 35 d compared to TN, respectively (P ≤ 0.05) and dietary SAA did not alter cloacal temperatures. At 28 d of age, supplementation of SAA to birds exposed to HS interacted as serum FITC-dextran (an indicator of intestinal permeability) was reduced to that of the TN group (P ≤ 0.05). The interaction was lost at 31 d, but HS still increased intestinal permeability (P ≤ 0.05). By 35 d, broilers were able to adapt to the HS conditions and intestinal permeability was unaffected (P > 0.05). Potential oxidative damage was reduced by increased SAA supplementation as indicated by an improvement in the reduced glutathione to oxidized glutathione ratio of 5 and 45% at 28 (P = 0.08) and 35 d (P ≤ 0.05). These data suggest that intestinal permeability is compromised initially and to at least three d of heat exposure before the bird can adjust. However, oxidative damage in the liver of broilers exposed to HS is more chronic, building over the entire 7 d HS period and increased dietary SAA might have some protective effects on both broiler intestinal permeability and oxidative stress responses to HS.
The effects of various concentrations of phytase on broiler growth performance, phosphorus digestibility, tibia ash, and phosphorus utilization
Mou, Connie (Virginia Tech, 2016-09-22)
Two experiments were conducted to determine the effects of various phytase concentrations on broiler growth performance, carcass composition, phosphorus digestibility, tibia ash and phosphorus utilization. The first experiment contained a positive control (PC) diet that was sufficient in all nutrients, a diet reduced in available phosphorus, calcium, amino acids and energy utilized as a negative control (NC) diet and the NC diet supplemented with two different phytase products at three inclusions (500, 1000, and 2000 FTU/kg) all fed to broilers over a 42-day period. The NC fed birds resulted in reduced growth performance by 42 days of age and phytase at 500 and 1000 FTU/kg had increased growth performance compared to NC (P<0.01), resulting in a similar response to the PC fed birds (P>0.05) indicating phosphorus and other nutrient release from the NC diet with phytase supplementation. Birds fed a diet supplemented with phytase A at 2000 FTU/kg outperformed the PC fed birds in body weight gain, feed efficiency, cold carcass weight, breast weight, breast yield, breast + tender weight and yield (P<0.01), but 2000 FTU/kg of phytase B resulted in poor responses often not improved in comparison to the NC fed birds (P>0.05). The second experiment utilized a standard curve to evaluate the use of phytase at various concentrations over a 14 day feeding assay. There were no differences between the two phytase treatments (500 and 2000 FTU/kg) in body weight gain, feed efficiency, feed intake or tibia ash weight (P>0.05). Standard curve analysis of tibia ash weight resulted in an estimate of 0.15 phytate phosphorus release from both phytase treatments. At 14 days, birds fed a treatment supplemented with phytase at 2000 FTU/kg showed an increase in apparent ileal phosphorus digestibility in comparison to 500 FTU/kg fed birds. The data may suggest that birds are digesting more phosphorus at an inclusion of 2000 FTU/kg phytase than 500 FTU/kg phytase but are not able to effectively utilize or store the nutrient as tibia ash showed similar mineral deposition between the two treatments. The concentration of non-phytate (nPP) in the Experiment 2 was 0.20% nPP (0.30% nPP in Experiment 1), which might have precluded the growth performance effects noted in Experiment 1. These two experiments indicate that phytase can act as a viable method in supplementing phosphorus and has the potential to increase broiler growth performance but results may vary depending on the phosphorus deficiency status of the diets before phytase supplementation.
Estimating energy utilization in laying hens: what are the best response criteria?
Lyons, Amy M.; Granghelli, C.A.; Persia, Michael E. (Elsevier, 2023-09)
An experiment was conducted to evaluate the effects of varying dietary energy on the performance and energy storage in laying hens from 36 to 52 wk of age. A total of 252 Hy-Line W-36 laying hens were housed in cages with 3 birds per cage and 12 replicate cages per treatment. Birds were control fed 1 of 7 experimental diets ranging in dietary energy from 2,750 to 3,050 kcal/kg with a 50 kcal/kg difference among each of the diets. Egg production, energy intake, feed intake, egg weight, egg mass, and feed efficiency were calculated every 2 wk so that performance data could be analyzed every 2 wk using repeated measures analysis. Hens were weighed every 4 wk for repeated measures analysis and carcass total, lean, and fat mass were determined at 52 wk using dual X-ray absorptiometry. Correlations between dietary energy and energy intake with performance parameters, and body composition were generated. Dietary energy (kcal/kg) was significantly correlated with all performance parameters except hen housed egg production (HHEP; P = 0.07) and lean carcass mass (P = 0.60). For dietary energy, the highest correlations were total carcass mass (r = 0.60) and carcass fat mass (r = 0.54). Energy intake (kcal/d) was significantly correlated with all performance parameters except feed intake (P = 0.18). The highest correlations were between energy intake and total carcass mass (r = 0.63) or body weight (r = 0.51). These results suggest that dietary energy has a more pronounced effect on body mass and fatty tissue over the short run (16-wk period) before direct performance responses are observed. Therefore, hen body weight and composition can be used as a more sensitive measurement of shorter-term hen energy status than egg production or feed efficiency.
Evaluation of a phytogenic feed additive on performance, nutrient digestion, and absorption in turkey poults
Zumbaugh, Charles Arthur III (Virginia Tech, 2018-01-24)
In recent years, there has been a growing interest in feeding phytogenic products to poultry for their growth and health benefits. The objective of this experiment was to determine the effects of a phytogenic feed additive on turkey poult performance and digestive physiology over a 6-week brooding period. In total, 864 male Hybrid Converter turkey poults were obtained from a local commercial hatchery on day-of-hatch and placed into floor pens with clean pine shavings. The treatments were randomly assigned including an industry-type corn-soybean meal positive control (PC), a similar diet with a 1.5% reduction in crude protein and key amino acids (NC), or the NC with the addition of Digestarom® (PFA) included at a rate of 1 g/kg. Body weight gain (BWG), feed intake (FI), feed efficiency (FE), and mortality were recorded throughout the experiment. On day 14 poults fed the PFA had significantly higher BWG compared to the PC and NC fed birds. By day 42 birds fed the PC and PFA diets had significantly higher BWG compared to the NC, and the PC had significantly higher FE compared to the NC and PFA fed birds. No differences in FI or mortality were observed throughout the experiment. There were no significant differences in AMEn, crude protein digestibility, or nutrient transporter or pancreatic enzyme mRNA expression among treatments. However, aminopeptidase activity tended to be lower in the ileum of poults fed the PC or PFA diets compared to the NC, suggesting that the PFA may be improving protein utilization.
Evaluation of the tryptophan requirement of small-framed first cycle laying hens
Wen, Jinlei; Helmbrecht, Ariane; Elliot, Michael; Thomson, John E.; Persia, Michael E. (2017)
Tryptophan is an essential amino acid, required for protein synthesis, and several metabolic processes in laying hens. Although required, the literature is mixed if tryptophan is considered the third or fourth limiting amino acid for laying hens and research on the tryptophan requirement in laying hens has been limited. The purpose of this experiment was to evaluate the tryptophan requirement of first cycle laying hens from 41 to 60 weeks of age. In total, 270 Hy-line W36 laying hens were randomly allocated to 6 treatments with 15 replicates of 3 birds for each experimental unit. Hens were maintained 3 to a cage (72 sq in/bird) in a multi-teared A-frame cage system within an environmentally controlled building. Hens were provided a 16:8 light schedule and 70 to 80 °F temperature program. A tryptophan deficient basal diet was formulated with corn, corn gluten meal and soybean meal with determined tryptophan, lysine and crude protein concentration of 0.096, 0.873, and 15.0%, respectively. Synthesized l-tryptophan was supplemented to the basal diet in 0.020% increments to generate experimental diets containing 0.096, 0.116, 0.136, 0.156, 0.176, and 0.196% tryptophan respectively. Hens were provided a controlled amount of feed daily resulting in approximately 95g/hen/d. The diet containing the lowest concentration of tryptophan resulted in reduced egg production and was halted at 45 weeks due to low performance with all other dietary treatments reaching the conclusion of the experiment at 60 weeks of age. Hen-housed egg production (HHEP) and mortality were monitored daily. Eggs were collected on two continuous days each week for feed conversion ratio (FCR) calculations and egg quality analysis. Single-slope broken line, multi-slope broken line and quadratic regression were used to estimate tryptophan requirement based on HHEP of the remaining five dietary treatments. Based on HHEP, optimum tryptophan requirement was 154.0, 142.8 and 193.7 mg/hen/d (single-slope broken line regression: Y=80.86+0.4871(X-154.02), R2=0.85; multi-slope regression: Y=3.127+0.5135X-0.3997(X-142.8), R2=0.85; quadratic regression: Y=-0.003046X2 +1.1802X-32.33, R2=0.85).

Browsing by Author "Persia, Michael E."

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