Clay J. Maynard

University of Arkansas at Fayetteville

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C.M. Owens

University of Arkansas at Fayetteville

Juan P. Caldas-Cueva

University of Arkansas at Fayetteville

M.T. Kidd

University of Arkansas System

Elizabeth S. Greene

University of Arkansas at Fayetteville

Xiao Sun

Chuzhou University

C.W. Maynard

University of Arkansas at Fayetteville

Sami Dridi

University of Arkansas at Fayetteville

S.J. Rochell

Auburn University

G.J. Mullenix

University of Arkansas at Fayetteville

Garrett J. Mullenix

University of Arkansas at Fayetteville

Cooperative Institutions

University of Arkansas at Fayetteville

University of Arkansas System

United States Department of Agriculture

Poultry Research Institute

Arkansas Agricultural Experiment Station

Texas A&M University

Chuzhou University

Mississippi State University

University of Sydney

Universidad Nacional Autónoma de México

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Impact of Phytase Supplementation on Meat Quality of Heat-Stressed Broilers

Animals (2023)

Clay J. Maynard C.W. Maynard Garrett J. Mullenix Alison Ramser Elizabeth S. Greene

Heat stress (HS) is one of the most challenging stressors to poultry production sustainability. The adverse effects of HS range from feed intake and growth depression to alteration of meat quality and safety. As phytase supplementation is known to improve nutrient utilization and consequently growth, we undertook the present study to evaluate the effects of dietary phytase on growth and meat quality in heat-stressed broilers. A total of 720 day-old hatch Cobb 500 chicks were assigned to 24 pens within controlled environmental chambers and fed three diets: Negative Control (NC), Positive Control (PC), and NC diet supplemented with 2000 phytase units (FTU)/kg) of quantum blue (QB). On day 29, birds were exposed to two environmental conditions: thermoneutral (TN, 25 °C) or cyclic heat stress (HS, 35 °C, 8 h/d from 9 a.m. to 5 p.m.) in a 3 × 2 factorial design. Feed intake (FI), water consumption (WI), body weight (BW), and mortality were recorded. On day 42, birds were processed, carcass parts were weighed, and meat quality was assessed. Breast tissues were collected for determining the expression of target genes by real-time quantitative PCR using the 2-ΔΔCt method. HS significantly increased core body temperature, reduced feed intake and BW, increased water intake (WI), elevated blood parameters (pH, SO2, and iCa), and decreased blood pCO2. HS reduced the incidence of woody breast (WB) and white striping (WS), significantly decreased drip loss, and increased both 4- and 24-h postmortem pH. Instrumental L* and b* values were reduced (p < 0.05) by the environmental temperature at both 4- and 24-h postmortem. QB supplementation reduced birds' core body temperature induced by HS and improved the FCR and water conversion ratio (WCR) by 1- and 0.5-point, respectively, compared to PC under HS. QB increased blood SO2 and reduced the severity of WB and WS under TN conditions, but it increased it under an HS environment. The abovementioned effects were probably mediated through the modulation of monocarboxylate transporter 1, heat shock protein 70, mitogen-activated protein kinase, and/or glutathione peroxidase 1 gene expression, however, further mechanistic studies are warranted. In summary, QB supplementation improved growth performance and reduced muscle myopathy incidence under TN conditions. Under HS conditions, however, QB improved growth performance but increased the incidence of muscle myopathies. Therefore, further QB titration studies are needed.

Phytase

10.3390/ani13122043

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Citations (7)

The effects of essential oil from Lippia origanoides and herbal betaine on performance, intestinal integrity, bone mineralization and meat quality in broiler chickens subjected to cyclic heat stress

Frontiers in Physiology (2023)

Roberto Señas-Cuesta Andressa Stein Juan D. Latorre Clay J. Maynard Xóchitl Hernández-Velasco

Essential oils (EO) affect performance, intestinal integrity, bone mineralization, and meat quality in broiler chickens subjected to cyclic heat stress (HS). Day-of-hatch Cobb 500 male broiler chicks ( n = 475) were randomly divided into four groups. Group 1: No heat stress (Thermoneutral) + control diets with no antibiotics; Group 2: heat stress control + control diets; Group 3: heat stress + control diets supplemented with thymol chemotype (45 ppm) and herbal betaine (150 ppm) formulation EO1; Group 4: heat stress + control diets supplemented with phellandrene (45 ppm) and herbal betaine (150 ppm) formulation EO2. From day 10–42, the heat stress groups were exposed to cyclic HS at 35°C for 12 h (8:00–20:00). BW, BWG, FI, and FCRc were measured at d 0, 10, 28, and 42. Chickens were orally gavaged with FITC-d on days 10 (before heat stress) and 42. Morphometric analysis of duodenum and ileum samples and bone mineralization of tibias were done. Meat quality was assessed on day 43 with ten chickens per pen per treatment. Heat stress reduced BW by day 28 ( p < 0.05) compared to thermoneutral chickens. At the end of the trial, chickens that received both formulations of EO1 and EO2 had significantly higher BW than HS control chickens. A similar trend was observed for BWG. FCRc was impaired by EO2 supplementation. There was a significant increase in total mortality in EO2 compared with EO1 EO1 chickens had lower FITC-d concentrations at day 42 than the HS control. In addition, EO1 treatment is not statistically different if compared to EO2 and thermoneutral. Control HS broilers had significantly lower tibia breaking strength and total ash at day 42 than heat-stressed chickens supplemented with EO1 and EO2. Heat stress affected intestinal morphology more than thermoneutral chickens. EO1 and EO2 improved intestinal morphology in heat-stressed chickens. Woody breast and white striping were more common in thermoneutral chickens than heat stress chickens. In conclusion, the EO-containing diet could improve broiler chicken growth during cyclic heat stress, becoming increasingly relevant in antibiotic-free production in harsh climates.

Betaine

Carvacrol

Thymol

Lippia

10.3389/fphys.2023.1184636

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Citations (6)

Failure of excess leucine to impact live performance and carcass traits in male and female Cobb MV × 500 broilers during a 15- to 32-day grower period

The Journal of Applied Poultry Research (2022)

C.W. Maynard G.J. Mullenix Clay J. Maynard J.T. Lee S.K. Rao

Modern broiler diets may contain excess levels of leucine due to the increased level of this amino acid in cereal grains. Excessive levels of leucine have previously been shown to negatively influence broiler performance due to branched-chain amino acid antagonism. Therefore, 2 leucine titrations were conducted in male and female Cobb 500 broilers. Low and high leucine diets were formulated to contain leucine to lysine ratios of 115 and 170, respectively. These diets were subsequently blended to produce 6 experimental diets containing leucine to lysine ratios of: 115, 126, 137, 148, 159, and 170. Pelleted diets were fed to 8 replicate pens of male and female broilers during a 15 to 32-day period. A subset of broilers was processed on day 33 for determination of carcass traits. Male broilers did not respond to excessive levels of dietary leucine. Increased leucine resulted in a positive quadratic response (P = 0.020) in feed intake for female broilers. The overall lack of a response of increased dietary leucine on male and female broilers indicate that industry levels of isoleucine and valine are likely of a sufficient level to overcome the effects of leucine excess.

Isoleucine

10.1016/j.japr.2022.100242

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Citations (5)

Novel 4th-generation phytase improves broiler growth performance and reduces woody breast severity through modulation of muscle glucose uptake and metabolism

Frontiers in Physiology (2024)

C.L. Walk Garrett J. Mullenix C.W. Maynard Elisabeth Greene Clay J. Maynard

The objective of the present study was to determine the effect of a novel (4th generation) phytase supplementation as well as its mode of action on growth, meat quality, and incidence of muscle myopathies. One-day old male broilers ( n = 720) were weighed and randomly allocated to 30 floor pens (24 birds/pen) with 10 replicate pens per treatment. Three diets were fed from hatch to 56- days-old: a 3-phase corn-soy based diet as a positive control (PC); a negative control (NC) formulated to be isocaloric and isonitrogenous to the PC and with a reduction in Ca and available P, respectively; and the NC supplemented with 2,000 phytase units per kg of diet (NC + P). At the conclusion of the experiment, birds fed with NC + P diet were significantly heavier and had 2.1- and 4.2-points better feed conversion ratio (FCR) compared to birds offered NC and PC diets, respectively. Processing data showed that phytase supplementation increased live weight, hot carcass without giblets, wings, tender, and skin-on drum and thigh compared to both NC and PC diets. Macroscopic scoring showed that birds fed the NC + P diet had lower woody breast (WB) severity compared to those fed the PC and NC diets, however there was no effect on white striping (WS) incidence and meat quality parameters (pH, drip loss, meat color). To delineate its mode of action, iSTAT showed that blood glucose concentrations were significantly lower in birds fed NC + P diet compared to those offered PC and NC diets, suggesting a better glucose uptake. In support, molecular analyses demonstrated that the breast muscle expression (mRNA and protein) of glucose transporter 1 (GLUT1) and glucokinase (GK) was significantly upregulated in birds fed NC + P diet compared to those fed the NC and PC diets. The expression of mitochondrial ATP synthase F0 subunit 8 (MT-ATP8) was significantly upregulated in NC + P compared to other groups, indicating intracellular ATP abundance for anabolic pathways. This was confirmed by the reduced level of phosphorylated-AMP-activated protein kinase (AMPKα1/2) at Thr172 site, upregulation of glycogen synthase (GYS1) gene and activation of mechanistic target of rapamycin and ribosomal protein S6 kinase (mTOR-P70S6K) pathway. In conclusion, this is the first report showing that in-feed supplementation of the novel phytase improves growth performance and reduces WB severity in broilers potentially through enhancement of glucose uptake, glycolysis, and intracellular ATP production, which used for muscle glycogenesis and protein synthesis.

Phytase

Gizzard

10.3389/fphys.2024.1376628

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Citations (3)

Impact of light intensity or choice of intensity on broiler performance and behavior

The Journal of Applied Poultry Research (2021)

D.J. Aldridge C.M. Owens Clay J. Maynard M.T. Kidd Colin G. Scanes

The optimal light intensities for broiler production and well-being have been investigated for some time. The use of a minimum 20 lux (lx) is mandated within the European Union (European Commission, 2000; European Union 2007). Light intensities below 20 lx are commonly used in the United States. There have been inconsistent effects of light intensities below 20 lx on broiler performance. The present study evaluated the performance of broiler chickens reared under 5, 10, and 20 lx or a choice between these intensities. The feed: gain ratio was the lowest for birds reared using 5 lx and the choice of 5, 10, and 20 lx (1.71 and 1.70) compared to 20 lx (1.81), with 10 lx being intermediate (1.74). Furthermore, there were no differences observed in carcass yield, breast yield or abdominal fat. Preference for different light intensities (5, 10, and 20 lx) was examined using a remote video system. On d 20, more birds were observed to be feeding under light intensities of 10 and 20 lx compared to 5 lx. All other (not feeding) birds preferred 20 lx on d 20. On d 31 birds feeding no longer displayed a preference while all others preferred 10 and 20 lx over 5 lx. On the final observation d 41 only those birds not feeding or drinking showed a preference for 10 lx. The results agreed with past studies in demonstrating the change of preference for light intensity. The use of choice lighting environments was able to provide the desired light intensity of broilers at a young age while maintaining production parameters of those reared using low intensity (5 lx).

Light intensity

Abdominal fat

Intensity

10.1016/j.japr.2021.100216

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Citations (12)

Effects of nicotinamide riboside in ovo feeding on high-yield broiler performance, meat quality, and myopathy incidence

Frontiers in Physiology (2024)

Clay J. Maynard J. M. Gonzalez Taketo Haginouchi Olivia G. Ellis Ashunti R. Jackson

The objective of this study was to examine the effects of

In ovo

10.3389/fphys.2024.1397442

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Meat quality traits and Blunt Meullenet-Owens Razor Shear characteristics of broiler breast fillets affected by woody breast condition and post-cooking meat temperature

Poultry Science (2021)

Xiao Sun Aline Giampietro‐Ganeco Ashleigh Mueller Clay J. Maynard Juan P. Caldas-Cueva

This study aimed to investigate meat quality attributes, cooking performance, and water properties of woody breast (WB). A total of 48 broiler breast fillets (7 wk, 3 h debone) of 24 normal (NORM) and 24 severe WB (SEV) were collected. Raw meat characteristics (L*, a*, b*, pH, compression force and energy and) along with the blunt blade of the Meullenet-Owens razor shear (BMORS) properties were determined. Cooking time and internal meat temperature were recorded for each fillet every 5 min on each fillet during cooking. Water/moisture properties and shear values of BMORS were determined at different meat temperatures (HOT [68°C], AMBIENT [22°C] and COLD [4°C]) after cooking. SEV fillets showed higher L*, a*, b*, pH, CF, CE, BMORS force, BMORS energy, and peak counts of BMORS values compared to NORM fillets in raw state (P < 0.05). Cooking time was shorter in SEV fillets than NORM fillets (P < 0.0001). Cook loss, total water loss, and moisture loss (HOT, AMBIENT) were greater in SEV fillets than NORM fillets (P < 0.01). PC-BMORS were greater in SEV fillets than NORM fillets (P < 0.05), and all BMORS shear values increased as post-cooking meat temperature decreased (P < 0.05). Positive correlations were observed between WB scores and raw meat characteristics and shear values. There were also significant relationships (P < 0.001) between WB scores and cooking performance measures except moisture loss for COLD treatment. BMORS force and energy were moderately correlated to total water loss, cook loss, and moisture loss (HOT) regardless of meat temperature (P < 0.05); however, PC-BMORS was only correlated to total water loss at COLD and moisture loss (HOT) at all meat temperatures (P < 0.05). These data corroborate the association of WB condition with impaired quality/texture characteristics in raw and cooked fillets; WB also had a significant impact on cooking time, cooking at a faster rate, along with water/moisture loss during and after thermal processing. Results demonstrate that the post-cooking meat temperature plays an important role in shear test values.

Fillet (mechanics)

Chicken breast

Water-Holding Capacity

Raw meat

10.1016/j.psj.2021.101212

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Citations (11)

Meat quality attributes of male and female broilers from 4 commercial strains processed for 2 market programs

Poultry Science (2023)

Clay J. Maynard A.R. Jackson Juan P. Caldas-Cueva Andy Mauromoustakos M.T. Kidd

In recent times, meat quality has become a key aspect of poultry production. In the current study, 2,400 sex separate broilers from four commercial strains were placed in six replications to evaluate various meat quality characteristics when grown to two market weights. Broilers were fed one of two diets with varying degrees of amino acid inclusion to evaluate meat quality of broiler raised on varying planes of nutrition. Birds were processed to meet two specified target weights (2.5 kg and 3.8 kg) representing small bird and big bird debone markets in the U.S., respectively. Birds were processed using commercial methods, deboned at 3 h postmortem, and meat quality was assessed. Myopathies (woody breast, white striping, spaghetti meat, along with tenderloin quality), fillet dimensions, color, water holding capacity (e.g., drip loss, cook loss), and Meullenet Owens Razor Shear was determined. Data were analyzed using the Mixed Model platform of JMP Pro 15.2 (SAS Institute, USA). Diet had no effect (P > 0.05) on the key quality responses; data was then pooled resulting in main effects of sex, strain, and target weight (noted as carcass size). On the day of processing, high yielding (HY) strains produced higher breast and tender yields (P < 0.05) when compared to standard yielding (SY) strains. In addition, and as expected, females exhibited higher breast and tender yields (P < 0.05) than males. However, males had significantly thicker (P < 0.05) and longer (P < 0.05) fillets, higher incidences (P < 0.05) of white striping, and higher (P < 0.05) cook loss when compared to females. Differences were also observed in tenderness as SY strain A produced the lowest shear values, whereas SY strain B produced the highest shear values across parameters (P < 0.05). SY strains in the small bird (SB) market performed better than SY strains in the big bird (BB) market as indicated by lower incidences of breast and tender myopathies white striping, woody breast, spaghetti meat, woody-like tender, and tender feathering and improved quality attributes (P < 0.05). Similar trends were observed (P < 0.05) in HY strains as SB carcasses produced a better overall product than BB. Differences in carcass size directly impacted quality (P < 0.05) as SB markets showed improvements in most parameters assessed, but broilers representing BB markets had greater breast yield. Although strain had minimal impacts on quality measures, carcass size and sex had a greater impact on muscle myopathies, water holding capacity, and shear properties.

White meat

Water-Holding Capacity

Chicken breast

10.1016/j.psj.2023.102570

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Citations (11)

Using air deformation of raw fillet surfaces to identify severity of woody breast myopathy in broiler fillets

LWT (2021)

Xiao Sun Clay J. Maynard Juan P. Caldas-Cueva C.N. Coon C.M. Owens

Fillet (mechanics)

10.1016/j.lwt.2021.110904

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Citations (11)

Understanding texture development in poultry meat

Burleigh Dodds series in agricultural science (2022)

Clay J. Maynard C.M. Owens

This chapter is intended to inform the reader on advances and developmental strategies in poultry meat tenderness. As is common with all food products, texture or tenderness, as the terms are interchangeably used, is the final “grade” that consumers place on a product. Meat tenderness is commonly known to be the hardest predicted trait for meat products as each consumer has their own level of acceptance. It should also be noted that texture development is a very intricate process that is multifaceted. The discussion to follow will focus on this multitude of factors that affect texture development and to express how complex final meat tenderness is in poultry products.

Poultry meat

Meat tenderness

Texture (cosmology)

10.19103/as.2022.0112.05

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