CO14 | EMERGING MYOPATHIES IN ORGANIC CHICKEN BREAST AND IMPLICATIONS FOR MEAT QUALITY

David Ranucci¹, Roberta Stocchi², Alessandro Cilla², Seyedalireza Kasayan², Francesca Mariotti², Rossana Roila¹, Andrea Cantarini¹, Caterina Altissimi¹, Raffaela Branciari¹, Ersilia Maria Epifanio³, Stefano Rea², Anna Rita Loschi² | ¹Dipartimento di Medicina Veterinaria - Università degli Studi di Perugia, Italy; ²Scuola di Bioscienze e Medicina Veterinaria - Università degli Studi di Camerino, Matelica, Camerino, Italy; ³Servizio Igiene degli Alimenti di Origine Animale e Derivati, Aulss 3 Serenissima, Dolo, Venezia, Italy.

Broilers from intensive farming frequently exhibit myopathies, although little research has been done on organic poultry. Therefore, the purpose of this study was to macroscopically categorize breast muscle alteration in medium-slow-growing chickens raised on an organic farm and assess how these changes related to physicochemical, colorimetric, rheological, and compositional factors. The following analyses were performed on 48 breast samples collected at the cutting plant from two distinct slaughter batches (spring - batch A and summer - batch B) of female chickens: visual inspection of lesions and classification of three emerging myopathies (white striping-WS, wooden breast-WB, and spaghetti meat-SM); recording of carcass weight and measurement of breast weight; post-chilling (3 h) and ultimate (48 h) post mortem pH measurement by penetration and by immersion, respectively; instrumental measurement of surface and internal Pectoralis major muscle colour (CIELAB); measurement of shear force in raw and cooked samples; texture profile analysis (TPA) of cooked samples; proximate chemical composition; determination of hydroxyproline content; histological examination of lesions, including histopathological assessments. To investigate the impact of the presence and severity of lesions in the Pectoralis major muscle on physicochemical, colorimetric, rheological, compositional, and histological parameters, a dual approach was adopted: evaluation of the correlation between the WS + WB scoring and all measured parameters using Pearson’s correlation coefficient (significance at p < 0.05); two-way analysis of variance (ANOVA) with batch (A and B) and lesion scoring classes of Pectoralis major myopathies (WS + WB) as fixed factors (Class A = score ≤ 1; Class B = score 2; Class C = score 3; Class D = score 4). Tukey’s post hoc test was used for mean comparison at a significance level of p < 0.05. The chickens from batches A and B had average live weights of 3.20 and 2.76 kg, respectively, and their mean breast weights were 735.5 g (standard deviation ± 132.4) and 543.1 g (± 117.8). Only one of the examined breasts (2.09% of the samples) had no macroscopic lesions that could be attributed to the myopathies under consideration. The other samples had varying degrees of WS and WB, which were distributed as follows: 14.58% in Class A (WS+WB score = 1), 37.50% in Class B (score = 2), 25.00% in Class C (score = 3), and 20.83% in Class D (score = 4). There were no samples with extreme WS values (score = 3) and no SM. Macroscopic scoring was shown to be significantly correlated with breast weight (r = 0.588, p < 0.001), internal muscle redness index (r = -0.297, p < 0.05), final pH (r = 0.488, p < 0.001), and proximal chemical composition. The latter showed a direct correlation with lipid content (r = 0.319, p < 0.05) and an inverse correlation with protein and ash levels (r = -0.342, p < 0.05 and r = -0.294, p < 0.05, respectively). Impact of breast weight on lesion severity (p < 0.001), variations in proximal composition between classes (p < 0.05), and histological evidence of different levels of fat infiltration and oedema linked to WS+WB classes (p < 0.05) were also detected.