Chicken meat is an important source of high-quality animal protein. Its consumption continues to grow in both developed and developing countries. Muscle fiber characteristics are key determinants of meat quality and quantity. Skeletal muscle is a highly plastic tissue that is affected by breed differences and muscular tissues. However, studies regarding the effects of different breeds and muscular tissues on the fibers and meat quality traits in broilers are lacking. In this study, Ross 308 chickens (fast-growing [FG] broilers) and Xueshan chickens (slow-growing [SG] broilers) were selected, and their fiber and meat quality traits were characterized. The results showed that the breast muscle primarily comprised glycolytic fibers, whereas the leg muscle comprised glycolytic and a few oxidative fibers, regardless of the breed. The highest percentage of oxidative fibers (26.51%) appeared in the soleus muscle (SOL) of SG broilers. In addition, higher shear force, lower pressing loss, and thicker muscle fibers with less extracellular space were observed for SG meat than for FG meat. When comparing the different muscular tissues, a higher oxidative fiber percentage, ultimate pH, redness, and intramuscular fat (IMF) content were detected in the leg muscle than in the breast muscle in the 2 breeds. In summary, these data indicated that SG broilers had thicker muscle fibers than the FG broilers and that the leg muscle had more oxidative fibers than the breast muscle. Thicker fibers may contribute to increased firmness and more oxidative fibers lead to higher redness value and IMF content.

This study evaluated the effects of muscle fiber characteristics on meat quality traits in 45 female fast- and slow-growing ducks. Three duck breeds at typical market ages were selected and slaughtered, including fast-growing ducks (Cherry Valley duck) and slow-growing ducks (Small-sized Beijing duck and Liancheng White duck). M. pectoralis major (PM), m. soleus (SOL), m. gastrocnemius (GAS) and m. extensor digitorum longus (EDL) were used to assess muscle fiber characteristics as well as meat quality properties. The results showed that the fiber compositions in PM, GAS, and EDL muscles only consisted of fast-twitch fibers irrespective of the breeds, while a low percentage of slow-twitch fibers were observed in slow-growing ducks (17.03% and 29.14%). The significant clear differences of fiber diameter, fiber density and fiber cross-sectional area (CSA) was observed among three duck breeds. Small-sized Beijing ducks had the highest diameter and cross-sectional fiber area coupled with a dramatically lowest fiber density when compared to other 2 breeds both in breast and leg muscles. In addition, the meat quality traits such as moisture content, release water, and intramuscular fat content were significantly affected by the breeds. Slow-growing ducks, especially Liancheng White ducks, exhibited higher release water, intramuscular fat content, as well as lower moisture content (P < 0.05) compared to the fast-growing ducks. The lower pH_{24 h} value and shear force tended to be present in breast of Liancheng White ducks (P < 0.05). The higher protein content and collagen content were detected in breast of Liancheng White ducks and the leg muscle of Small-sized Beijing ducks (P < 0.05), respectively. Finally, the correlation coefficients between muscle fiber characteristics and meat quality showed that the diameter, density and CSA of fibers had a moderate or significant correlation with pH, shear force value, moisture content, and protein content of meat in fast-growing ducks. In slow-growing ducks, muscle fiber characteristics had a moderate or significant correlation with pH, shear force value, release water, protein content, and intramuscular fat content of meat. These results indicated that muscle fiber characteristics is a useful parameter to explain in parts the variation of meat quality including pH, shear force value, and protein content of meat, both in slow-growing ducks and fast-growing ducks.

Goose meat is increasingly popular among consumers because of its good quality. The fiber characteristics have been well demonstrated to be key contributing factors of meat quality, and the marketable ages are also closely related to meat quality. However, little is known about the effect of different marketable ages on the quality of goose meat through its fiber characteristics. Here, fiber characteristics of Yangzhou geese of different marketable ages (70, 90, and 120 d) and their effect on meat quality were investigated. The results showed that only fast-twitch fibers were present in breast muscle, irrespective of age, and that few slow-twitch fibers could be identified in leg muscle, especially in gastrocnemius and extensor digitorum longus. Fiber diameter in breast muscle increased rapidly from age 70 d to 90 d, from 19.88 to 26.27 μm, and remained stable for 90 d thereafter. The diameter and cross-sectional area of muscle fiber continue to grow with day increasing in leg muscle. In addition, we measured the proximate composition and physical properties at different ages. Among the 3 marketable ages investigated, the 120-day-old geese had higher intramuscular fat and protein content, as well as lower moisture content, both in breast and leg meat. Greater lightness and pressing loss, with lower redness and shear force, were observed in the breast and leg meat of 70-day-old geese when compared with 90- or 120-day-old geese. Taken together, although older marketable age hardly affected muscle fiber type in geese, it would contribute to larger muscle fiber area, higher intramuscular fat and protein content, as well as redder and chewier meat. As a result, the reasonable marketable age should be taken into account to improve quality in goose meat production, and the marketable age of 90 or 120 d was recommended and it could potentially improve meat quality in goose meat production.

The selection of broilers for augmented growth rate and breast yield has been accompanied by deterioration in meat quality. To characterise the meat quality differences between slow- (SG) and fast-growing broilers (FG), Xueshan and Ross 308 chickens were employed to determine the mechanisms causing these differences. SG meat was found to display more redness and yellowness, higher shear force, pH_24h, and protein content, with lower intramuscular fat (IMF) content than FG meat. Further, based on comparative phosphoproteomic analysis (SG/FG), upregulated phosphorylated myofibrillar proteins resulted in larger fibres, which contributed to lower pressing loss and tenderness. The phosphoproteins of glycolytic enzymes, phosphorylase kinases, and calcium-related proteins were significantly downregulated, which reduced the acidity of the meat. SLC7A5 at Ser21, MRC2 at Ser1359 and CRAT at Ser341, AUP1 at Ser377 positively affected protein and IMF deposition, respectively. Together, these phosphoproteins elicit vital information for the genetic improvement of chicken meat quality.

Egg production in different goose breeds vary significantly, which is related with the physiology of reproduction. However, the knowledge of physiolo