Influences of Thermal Stress During Three Weeks Before Market Age on Histology and Expression of Genes Associated With Adipose Infiltration and Inflammation in Commercial Broilers, Native Chickens, and Crossbreeds

Fibroadipogenic progenitors: a potential target for preventing breast muscle myopathies in broilers

Genetic selection for high growth rate, breast muscle yield, and feed efficiency in modern broilers has been a double-edged sword. While it has resulted in marked benefits in production, it has also introduced widespread incidence of breast muscle myopathies. Broiler myopathies are phenotypically characterized by myodegeneration and fibrofatty infiltration, which compromise meat quality. These lesions resemble those of various myopathies found in humans, such as Duchenne muscular dystrophy, Limb-girdle muscular dystrophy, and sarcopenia. Fibroadipogenic progenitors (FAPs) are interstitial muscle-resident mesenchymal stem cells that are named because of their ability to differentiate into both fibroblasts and adipocytes. This cell population has clearly been established to play a role in the development and progression of myopathies in mice and humans. Gene expression studies of wooden breast and other related disorders have implicated FAPs in broilers, but to our knowledge this cell population have not been characterized in chickens. In this review, we summarize the evidence that FAPs may be a novel, new target for interventions that reduce the incidence and development of chicken breast muscle myopathies.

The amino acid pattern and dynamics of body protein, body fat deposition in male and female broilers under different temperatures

The present study was conducted 1) to investigate the effects of gender and temperature on growth performance in broiler chickens and 2) to establish body protein and fat deposition curves and amino acid patterns for broilers of both genders at different ambient temperatures. A total of 432 1-day-old (d) Arbor Acres chickens with a male/female ratio of 1:1 were randomly divided into the following 4 treatment groups: the male thermoneutral group, the female thermoneutral group, the male heat stress group, and the female heat stress group. The chickens in the thermoneutral groups were kept at a comfortable temperature from 1 to 42 d, while chickens in the heat stress groups were kept at a comfortable temperature from 1 to 28 d and at a high ambient temperature from d 29 to 42. The body composition retention data were obtained by comparative slaughter method, and the models were constructed by the Gompertz model. The results revealed significant variation in body protein content (BPC) and body fat deposition efficiency (BFE) between both genders and the 2 temperatures. Moreover, a noteworthy interaction between gender and temperature was observed in terms of the BPC and protein deposition efficiency (BPE). The following equations for body protein and body fat deposition in the thermoneutral groups were obtained: Body protein weight of male broilers: [Formula: see text] ; Body protein weight of female broilers: [Formula: see text] ; Body fat weight of male broilers: [Formula: see text] ; Body fat weight of female broilers: [Formula: see text] . Where t means age (d). The following equations for body protein and body fat deposition in the heat stress groups were obtained: Body protein weight of male broilers: [Formula: see text] ; Body protein weight of female broilers: [Formula: see text] ; Body fat weight of male broilers: [Formula: see text] ; Body fat weight of female broilers: [Formula: see text] . Where t means age (d). In addition, no significant difference in amino acid content was found between different genders and temperatures. The amino acid pattern could be divided into 2 stages: 0 to 14 d and 15 to 42 d. Our equations and patterns enable a deeper understanding of the nutritional requirements in broiler chickens under various temperature conditions. This enables researchers to develop more accurate feeding programs to fulfill the growth and health requirements of broiler chickens.