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PHOTO: MICHEL ZOETER
MEAT QUALITY ▶▶▶
Where the fork hits the plate
Skeletal muscle is complex and dynamic. Its functional characteristics and metabolic properties adapt based on environmental and physiological factors. Therefore, changes to an animal’s genetics, growth rate, nutrition, locomotion and metabolism can greatly alter skeletal muscle composition and, ultimately, meat quality.
BY REBECCA M. DELLES, ALLTECH M
inerals are indispensable nutrients involved in various biological processes, such as metab ol- ism, reproduction and immunity. They serve as activators and co-factors for various enzymes
and are critical components of cellular membranes. In muscle, mineral concentration depends on mineral absorptivity, mus- cle type, animal age and genetics, as well as environmental factors. As such, alterations in mineral nutrition can dramati- cally impact the overall health and wellness of the animal and thus, product quality.
Meat quality Meat quality measures the organoleptic and physiochemical properties of fresh or value-added meat. In recent years, breast muscle myopathies, such as wooden breast meat, have afflicted the poultry industry. Typically, wooden breast (WB) can be found in fast-growing, heavy-breasted birds and is characterised as hardened, bulging, pale meat often accompa- nied by white striping of the pectoralis major. Wooden breast
Figure 1 – Effects of dietary treatments on the P<0.01
Se concentration of breast meat. 1800 1600 1400 1200 1000 800 600 400 200 0
b Control 24 ▶ POULTRY WORLD | No. 5, 2022 a
tends to have an altered nutritional content and impaired quality compared to normal breast meat. While still usable, wooden breast is typically downgraded and further processed leading to substantial economic losses to the poultry industry. Extensive research has focused on determining the underlying mechanism of wooden breast myopathy, and while causation has not been fully elucidated, there are a variety of factors that appear to correlate to the development of wooden breast meat. Genomic and metabolic studies have revealed several dysregulated molecular pathways involved in oxidative stress, circulatory oxygen homeostasis, muscle bioenergetics, in- flammatory response and muscle repair. There is a growing body of evidence that oxidative stress, with varying degrees of importance, plays a role in the onset or progression of several myopathies, including wooden breast. Petracci and others (2019) hypothesized that the accumulation of metabolic waste products associated with increased metabolic and cir- culatory demand from rapid hypertrophy results in increased oxidative stress. Due to the complex and multifaceted process of developing wooden breast myopathy, utilising a wide varie- ty of tools from management practices to nutritional solutions aimed at lessening oxidative stress and inflammation and supporting vascularization, may abate the development and severity of breast muscle myopathies.
TRT
Oxidative stress Oxidative stress is combated through the cell’s antioxidant enzymatic defence system and non-enzymatic molecules, such as glutathione and metal-binding proteins. Key antiox- idant enzymes include glutathione peroxidase, catalase and superoxide dismutase, all of which require specific minerals for appropriate function. Surai (2002) suggests that oxidative stress in the live animal is due to an imbalance between ROS and reactive nitrogen species and the antioxidant defence mechanism, necessitating proper nutrient intake. Nutritional strategies, such as arginine, selenium, trace minerals and vitamin C, have been considered to reduce the incidence of wooden breast myopathies. Combining gene expression data of WB and compiled data on mineral supplementation and oxidative stress, the question was investigated of whether the trace minerals that are rou- tinely supplied to modern broilers meet the demands to prop- erly support the bird’s antioxidant system and protect against
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