Effect of strain and nutritional density of the diet on the water-protein ratio, fat and collagen levels in the breast and legs of broilers slaughtered at different ages

Abstract

Many requirements are necessary to meet the European Union rules to export poultry, including the amount of physiological water and water-protein ratio ( WPR ) in carcasses. Therefore, the aim of this study was to identify if strain, nutrition, and age affect the amount of collagen and fat and the WPR in cuts and verify whether the latter meets the international export standards. A total of 3,240 male chicks were housed in a completely randomized design in a 3 × 3 × 5 factorial arrangement, which included 3 nutritional densities (regular, medium, and high), 3 strains (021 Embrapa and 2 commercial strains identified as A and B), and 5 ages. Twelve broilers from each treatment (totaling 540 birds) were slaughtered at 28, 35, 42, 49, and 56 D of age to determine collagen and fat levels and WPR (through the calculation of moisture and protein percentage) in broiler breasts and legs using the near-infrared spectroscopy method. The use of feeds with different nutritional densities presented in this study has no effect on the WPR in the breast and legs of broilers slaughtered between 28 and 56 D of age. However, nutritional density influences liveweight and percentage of fat in the breast and legs. Collagen percentage in the legs decreases with increasing nutritional density. The 021 Embrapa strain cuts present a lower WPR than those of other commercial strains. However, the values found for all strains studied are within the limits of the Europe Union and Brazilian legislations. The liveweight, breast weight, leg weight, and leg fat increases linearly with age. Quite the opposite, water protein ratio, breast fat level, and breast collagen level decrease linearly with age. Leg WPR and leg collagen level are not affected by age. Despite the differences found for strains, nutritional densities and age readers should be aware that these factors may interact with each other depending on the response variable studied.

Chemical Composition of the “Galo de Barcelos” (Barcelos Rooster Raw Meat)

“…Concerning protein, our results were very similar to those described in the literature for autochthonous breeds and broilers [ 30 , 33 , 35 , 36 ]. The effect of the genotype was observed, in accordance with different studies with indigenous breeds, not submitted to genetic selection for productive performance and meat quality characteristics, presenting greater variability when compared to commercially used hybrids [ 33 , 35 , 36 , 37 ].…”

Carcass and Meat Quality Traits of Males and Females of the “Branca” Portuguese Autochthonous Chicken Breed

“…Compared to commercial lines, including studies carried out under organic and conventional conditions, mean values of protein were higher than those reported in improved hybrid commercial breeds for meat production and broilers (19.90–23.53% vs. 16.09–19.42%) [ 58 , 59 , 60 ], spent hens (21.50–22.37% vs. 10.00–19.46%) [ 58 , 61 , 62 ] and broilers in an organic system (20.60–22.76% vs. 19.01–19.47%) [ 38 , 51 , 63 ], breast and drumstick, respectively. These differences can be explained by diverse factors, such as age, feed management and production system [ 30 , 35 , 64 , 65 ], with a significant influence on muscle development, which affects the deposition of proteins in meat [ 11 ].…”

Growth Performance Analysis of Two Italian Slow-Growing Chicken Breeds: Bianca di Saluzzo and Bionda Piemontese

“…In spite of this, the degree of maturity puts the BS at some disadvantage compared to the BP (Dm < 0.80) and its growing potential could be not fully exploited. Prediction of the best maturity for sale is a complex experimental task [ 54 , 55 ], particularly outside the industrial farming. Nevertheless, a rough estimate may be attempted.…”

“…The Dm should increase with no additional costs. The mathematical models may also provide suitable information to optimize management (environmental conditions, diet) and evaluate effects on carcass components and meat quality to guarantee a source of niche high quality food [ 19 , 20 , 47 , 48 , 55 , 58 ].…”