Combined effect of divergent selection for breast muscle ultimate pH and dietary amino acids on chicken performance, physical activity and meat quality

Abstract

Responses to changes in dietary Lys and other essential amino acid (AA) concentrations were evaluated in 480 male and female broilers originating from two lines divergently selected for high (pHu+) or low (pHu−) ultimate pH (pHu) of breast muscle. The two genetic lines were fed with two grower isoenergetic diets differing in both true digestible Lys (control = 10.2 g/kg and experimental = 7.0 g/kg) and amounts of other essential AA calculated in relation to Lys, which were sufficient for the control diet or in excess for the experimental diet. There were six repetitions per treatment. Birds were weighed individually at days 0, 21, 28 and 43. Feed consumption was recorded per pen and feed conversion was calculated over the growing period. The physical activity and walking ability of broilers were recorded during the whole rearing period. Breast and leg yield, and abdominal fat percentage were measured at 43 days of age, as were pHu, color, drip and cooking loss, Warner-Bratzler shear force, and curing-cooking yield of the breast Pectoralis major and pHu of the thigh Sartorius muscle. Divergent selection greatly affected most breast meat quality traits without significantly changing growth rate or feed efficiency. When subjected to a variation in dietary intake of AA, birds from the two genotypes responded in a similar way in terms of animal's growth, feed efficiency, body composition and meat quality traits. Although line and diet did not affect physical or feeding activities of the broilers, a significant effect of line-by-diet interaction was observed on gait score. Contrary to the pHu− birds, the walking ability of pHu+ birds was impaired when fed the control diet that favored growth and breast muscle development and limited storage of carbohydrate in muscle.

Early Growth and Protein-Energy Metabolism in Chicken Lines Divergently Selected on Ultimate pH

“…In chickens, a near-perfect genetic correlation (of −0.97) was established between the in vivo glycogen content of breast muscle and pHu, which is a key factor of meat quality (Le Bihan-Duval et al, 2008). In this species, selection for increased growth rate and/or breast muscle mass has been associated with reduced in vivo glycogen storage and in turn with higher pHu (Berri et al, 2001(Berri et al, , 2007; according to recent studies, this could be a condition associated with a greater occurrence of degenerative disorders such as WS and WB defects (Kuttappan et al, 2009;Petracci et al, 2013;Abasht et al, 2016;Alnahhas et al, 2016Alnahhas et al, , 2017. The understanding of the biological determinism of glycogen content is thus a key point for the control of muscle integrity and meat quality in chickens.…”

Muscle transcriptome analysis reveals molecular pathways and biomarkers involved in extreme ultimate pH and meat defect occurrence in chicken

“…To improve our knowledge of the genetic and physiological control of meat pHu, we recently developed two broiler lines (pHu+ and pHu-) that exhibit quite different muscle pHu values after 5 generations of divergent selection but show, at the same time, similar growth performance and body composition 12 . The between-line difference in the pHu values is related to significant differences in the muscle glycogen content and many other meat quality traits, including colour, water-holding capacity, texture, processing yield, as well as white striping occurrence 3,[12][13][14] . Therefore, the pHu+ and pHu-lines constitute an excellent model to study the molecular pathways specifically involved in the control of poultry meat quality traits related to pHu and glycogen storage in muscle.…”

“…After only five generations of divergent selection 12 , this experiment led to the creation of two lines, namely the pHu-and the pHu+ lines, which are respectively characterised by a very low and very high pHu. These two lines were recently fully characterised for their phenotypes related to meat quality attributes [12][13][14] and for their serum and muscle metabolomics profiles 15 . The metabolomics approach allowed for the identification of 20 and 26 discriminating metabolites in the serum and muscle, respectively, and a set of 7 potential pertinent biomarkers of the pHu in the serum 15 .…”

Partial Substitution of Fermented Soybean Meal for Soybean Meal Influences the Carcass Traits and Meat Quality of Broiler Chickens

“…Approximately 5 g of muscle was weighed and put into zip-lock plastic bags, hung from a hook, and left at 4 • C for 24 h. Then, the surface moisture of the sample was absorbed with filter paper and the sample was reweighed. According to the method of Alnahhas et al [21], approximately 30 g of muscle was weighed, wrapped in an airtight polythene bag, and cooked in a water bath at 85 • C for 13 min (internal temperature 70 • C). Afterwards, the samples were cooled in crushed ice for 10 min, wiped dry using absorbent paper, and weighed.…”