Source: UNIV OF MARYLAND submitted to
REDUCING BROILER BREAST MYOPATHIES THROUGH NUTRITIONAL INTERVENTIONS AND PROCESSING ADJUSTMENTS
Sponsoring Institution
State Agricultural Experiment Station
Project Status
(N/A)
Funding Source
Reporting Frequency
Annual
Accession No.
1033636
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jan 22, 2025
Project End Date
Jun 30, 2026
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Project Director
Che, SU, .
Recipient Organization
UNIV OF MARYLAND
(N/A)
COLLEGE PARK,MD 20742
Performing Department
Animal and Avian Sciences
Non Technical Summary
Spaghetti meat (SM) and Woody Breast (WB) are significant challenges facing the broiler chicken industry, causing substantial economic losses and reduced consumer acceptance. These myopathies, characterized by abnormal muscle textures, affect a considerable percentage of broiler chickens, with SM prevalence ranging from 35% to 36% and severe WB ranging from 11% to 27%. The estimated annual loss due to these conditions in the USA alone is $1 billion. This research project aims to address these issues by investigating potential mitigation strategies, which is crucial not only for the poultry industry but also for broader economic, community, and environmental concerns related to food production efficiency and quality.The research will employ a multifaceted approach to tackle this problem. The project will utilize 1,584 male Ross 708 chicks to study the effects of dietary supplementation with guanidinoacetic acid (GAA) at different concentrations (0%, 0.06%, and 0.12%) on the incidence and severity of SM and WB. Additionally, the influence of chilling time and temperature during commercial processing will be assessed. The study will also delve into the histological and molecular mechanisms underlying these myopathies through advanced techniques such as histological analysis and RNA sequencing. By combining these methods, the project aims to develop optimized feeding strategies and processing protocols that can be integrated into existing production systems. Ultimately, this research seeks to improve broiler meat quality, enhance protein production efficiency, and contribute to more sustainable meat production practices, potentially leading to significant societal benefits in terms of food security, animal welfare, and resource conservation.
Animal Health Component
70%
Research Effort Categories
Basic
30%
Applied
70%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3053220102070%
3073220117030%
Goals / Objectives
Spaghetti meat (SM) and Woody Breast (WB) are concerning issues in the broiler chicken industry. SM is characterized by the separation of muscle fiber bundles in the Pectoralis major muscle, resulting in a mushy, stringy texture. In contrast, WB is characterized by an abnormal hardening or firmness of the breast muscle, often accompanied by pale color and occasional petechial hemorrhages. The prevalence of both myopathies is substantial, with SM ranging from 35% to 36% and severe WB ranging from 11% to 27%. These conditions lead to reduced consumer acceptance and product depreciation, causing substantial losses in the poultry industry, with an estimated annual loss of $1 billion in the USA.The major goal of this research is to investigate and mitigate the incidence and severity of P. major defects, specifically SM and WB, in broiler chickens. Although there are a couple of studies that have investigated the effects of supplements on the incidence of broiler myopathies, no experiment has explored the effect of 0.12% GAA supplementation on SM, nor the effect of chilling time and temperature.The specific objectives are as follows:Investigate the effect of 0.06% and 0.12% GAA supplementation on the incidence and severity of WB and SM in Ross 708 broiler chickens.Assess the influence of temperature and duration of the chilling process in commercial processing plants on the development of SM in Ross 708 broiler chickens.Understand the histological and molecular mechanisms of SM and WB using histology and RNA sequencing.
Project Methods
The experiment will be conducted at the Applied Poultry Research Laboratory (APRL) of the University of Maryland, utilizing 1,584 male, day-of-hatch Ross 708 chicks. The birds will be housed in 72 pens across two rooms (blocks), with each room containing 36 pens (12 pens x [one control and 2 treatments]). Each pen, measuring 7 ft. x 6.3 ft., will accommodate 22 birds, providing a stocking density of 2 ft² per bird. The pens will be equipped with feeders and waterlines, allowing ad libitum access to feed and water.Three dietary treatments will be employed:Control Diet: A baseline without any GAA supplementation0.06% GAA-Supplemented Diet: Control diet supplemented with 0.06% GAA0.12% GAA-Supplemented Diet: Control diet supplemented with 0.12% GAAAll diets will be formulated to be isoenergetic and isonitrogenous, representing typical U.S. broiler industry practices, and will follow Ross 708 nutrition specifications using a 4-phase diet program. Treatments will be randomly assigned within each block to control for potential variability between rooms. Feed will be prepared in four phases: starter (crumbles, d0-18), grower (pellets, d19-28), finisher (pellets, d29-42), and withdrawal (pellets, d43-49 or until target weight of 7 lb or 3.18 kg is reached). Feed will be produced at a local feed mill using methods from a previous study.Birds will follow an automatic lighting schedule, transitioning from 24 hours of light for the first two days to a 17:7 schedule (17 hours of light and 7 hours of darkness) by day 8, with a light intensity of 5 lux. Mortality data will be collected daily. Body weight and feed intake data will be recorded for each pen at days 18, 28, 42, and upon reaching market weight to calculate the feed conversion ratio.The main effect investigated in this study is the influence of the dietary treatments on the chickens' growth metrics, as well as the incidence and severity of SM and WB. When chickens reach a target weight of 7 lb (3.2kg), they will be transported to a local chicken processing plant and processed under different conditions. Breast fillets will be scored for the incidence and severity of myopathies.Histological AnalysisP. major sample tissues will undergo histological examination using standard techniques, such as hematoxylin and eosin (H&E) and Masson's trichrome staining, based on a previously established scoring scheme. In the Che lab, tissue samples will be collected by cutting a core (1 x 1 x 1 cm) from the superficial cranial portion of each fillet. Tissues will be fixed in 10% formalin, embedded in paraffin, and processed for H&E and Masson's trichrome stains to measure myodegeneration, accumulation of inflammatory cells, fibrosis, and lipidosis under a light microscope.RNA SequencingRNA sequencing will be performed on chicken breast muscle tissues to identify differentially expressed genes and molecular pathways associated with SM and WB. P. major tissue samples, weighing approximately 1-2 grams, will be collected from the superficial, cranial portion of the breast fillets. These tissue samples will be obtained from the same breast fillets that were previously used for histological analysis at the processing plant. The samples will be stored in RNAlater solution for preservation. Total RNA will be extracted, and samples with an RNA integrity number greater than 7 will be selected for sequencing. The sequencing process will involve mRNA enrichment, cDNA synthesis, DNA fragmentation, adapter ligation, library amplification, and library analysis. Paired-end sequencing will be conducted, and FASTQ reads will be generated using Bioconda packages. Adaptor sequences and low-quality bases will be trimmed, and the resulting reads will be aligned to the latest chicken genome assembly. Differentially expressed genes will be identified using R packages and visualized using principal component analysis plots and heatmaps. Pathway enrichment analyses, such as Gene Ontology and KEGG, will be performed to gain insights into the genetic factors and regulatory mechanisms contributing to SM and WB development.