Restricted Feeding Regimens Improve White Striping Associated Muscular Defects In Broiler Chickens

Background: Ad libitum (AD) feeding is crucial to profitable commercial broiler chicken production. However, it partly disrupts muscle development, causing myopathies like white striping in broilers’ breast meat. For this reason, this study investigated the impacts of intermittent feeding (IF) and fasting strategies as potential alternatives to AD feeding. A total of 384 one-day-old broilers were randomly allotted into 4 groups - ad libitum, 1h-IF group (4 times/day, 1 hour each time), 1.5h-IF (4 times/day, 1.5hrs each time), and acute fasting (1-day acute fasting, 6-days free access to feed). Feed intake, weight gain, muscle structure, differential genes, and protein expressions were assessed in the broiler breast muscles. Results: IF and fasting significantly reduced ectopic fat deposit and muscle fiber size (p < 0.05). Notably, 1.5h-IF promoted PAX7+ satellite cell proliferation supporting muscle growth and repair activities in fast-growth broiler chickens. Consistently, the restricted regimens downregulated the collagen protein synthesis of skeletal muscle-specific E3 ubiquitin ligases (TRIM63 and MAFBX) in 42 – days old breast muscle samples (p < 0.05), especially in the 1.5h-IF group. Compared to AD-fed birds, 1.5h-IF and fasting feeding significantly decreased white striping scores in the breast meat muscle (p < 0.05). ConclusionChronic IF or acute fasting improved muscle health of broiler chickens without significant compromise on growth rate and feed efficiency compared to AD feeding. Therefore, this study presents potential feeding frequencies relevant for optimal growth pace while alleviating the occurrence of myopathic pathophysiology in broiler chickens.

Differential Expression of Myogenic and Calcium Signaling-Related Genes in Broilers Affected With White Striping

White Striping (WS) has been one of the main issues in poultry production in the last years since it affects meat quality. Studies have been conducted to understand WS and other myopathies in chickens, and some biological pathways have been associated to the prevalence of these conditions, such as extracellular calcium level, oxidative stress, localized hypoxia, possible fiber-type switching, and cellular repairing. Therefore, to understand the genetic mechanisms involved in WS, 15 functional candidate genes were chosen to be analyzed by quantitative PCR (qPCR) in breast muscle of normal and WS-affected chickens. To this, the pectoral major muscle (PMM) of 16 normal and 16 WS-affected broilers were collected at 42 days of age and submitted to qRT-PCR analysis. Out of the 15 genes studied, six were differentially expressed between groups. The CA2, CSRP3, and PLIN1 were upregulated, while CALM2, DNASE1L3, and MYLK2 genes were downregulated in the WS-affected when compared to the normal broilers. These findings highlight that the disruption on muscle and calcium signaling pathways can possibly be triggering WS in chickens. Improving our understanding on the genetic basis involved with this myopathy might contribute for reducing WS in poultry production.

Spaghetti Meat Abnormality in Broilers: Current Understanding and Future Research Directions

Spaghetti meat (SM) is a recent muscular abnormality that affects the Pectoralis major muscle of fast-growing broilers. As the appellative suggests, this condition phenotypically manifests as a loss of integrity of the breast muscle, which appears soft, mushy, and sparsely tight, resembling spaghetti pasta. The incidence of SM can reach up to 20% and its occurrence exerts detrimental effects on meat composition, nutritional value, and technological properties, accounting for an overall decreased meat value and important economic losses related to the necessity to downgrade affected meats. However, due to its recentness, the causative mechanisms are still partially unknown and less investigated compared to other muscular abnormalities (i.e., White Striping and Wooden Breast), for which cellular stress and hypoxia caused by muscle hypertrophy are believed to be the main triggering factors. Within this scenario, the present review aims at providing a clear and concise summary of the available knowledge concerning SM abnormality and concurrently presenting the existing research gaps, as well as the potential future developments in the field.

White Striping and Wooden Breast Myopathies in the Poultry Industry: An Overview of Changes in the Skin, Bone Tissue and Intestinal Microbiota and Their Economic Impact

Considerable advances in the poultry industry have been observed in the last sixty years. Consequently, new technological and biological processes have accompanied the development of animals and inputs. With these new possibilities and growth in the sector, there was also the emergence of new paradigms, one of which being the different types of myopathies. In the poultry industry, the breast is one of the noble parts and, therefore, a lot has been studied about the occurrences, alterations and/or different myopathies that alter its quality characteristics. Here we will highlight White striping (WS) and Wooden breast (WB), both investigated more recently due to changes in quality characteristics and considerable losses. The objectives of this review will be to discuss the biochemical parameters of these meats affected by myopathies WS and WB and their consequences on the development of skin, bone and intestinal microbiota lesions; correlate with the impacts of these occurrences to economic losses associated with partial and total condemnations of the carcasses. Another approach is that fast-growing animals have a drop in their quality of life, impacting the well-being of birds since the inflammatory process and excess weight have a direct correlation with dermatitis, corns, arthritis and other comorbidities.