The effects of overfeeding on myofibre characteristics and metabolical traits of the breast muscle in Muscovy ducks (Caïrina moschata)

Abstract

-The aim of this experiment was to study the consequences of precise feeding on the myofibre characteristics and metabolic traits of the breast muscle (Pectoralis major, Pm) of Muscovy ducks. Twenty-four samples of breast muscle, without skin or subcutaneous fat, from two groups of ducks, control and overfed respectively, were collected at 14 weeks of age. We assayed different chemical (water content, crude proteins, total lipid ashes, total and thermosoluble collagen), biochemical (activities of the CS, LDH and β-HAD enzymes), histological (muscle fibre typing and intramuscular adipocyte measurements) and technological (drip and cooking losses, texture) determinations. At the force-feeding period, the overfed ducks weighed 6366 g and the control ducks 4606 g of body weight. In the PM muscle, some modifications of the biochemichal parameters and enzyme activities were observed but neither the shear force nor the histological characteristics of the breast muscle were affected by the fattening treatment. The overfed birds had an increased total lipids content (correlated to an increase in the intramuscular area occupied by the adipocyte) and a different fatty acid profile as the result of a higher energy feed intake. The lipids of the Pm muscle of the overfed ducks contained more C16:0, C16:1n-7 and C18:1n-9, but less C18:0, C18:2n-6 and C20:4n-6 than the control birds. These results show that in response to high energy feeding, the muscle is able to respond quickly on a metabolic basis (by increasing the activities of the oxydative enzymes) without changing its typology or morphology. Additionally, fattening was correlated to a degradation in the technological qualities of the breast muscle, especially an increase in the cooking losses. muscovy duck / force feeding / Pectoralis major / muscle typing / fatty acid Reprod. Nutr. Dev. 43 (2003) [105][106][107][108][109][110][111][112][113][114][115] 105

Effect of genotype and overfeeding on lipid deposition in myofibres and intramuscular adipocytes of breast and thigh muscles of ducks

“…We observed a large increase in the relative surface occupied by adipocytes on muscle sections: 1.5 fold in P. major and 2.1 fold in Sartorius across genotypes. This confirmed the previous observations of Zanusso et al [20] obtained in Muscovy ducks. The availability of data across a wide range of muscle lipid concentrations in P. major allowed obtaining high correlations between the relative surface occupied by adipocytes in muscle sections and the total lipid (g per Figure 2.…”

“…In P. major muscle, overfeeding had no significant effect on the total lipid content of muscle fibres (luminance of Sudan black B staining). Zanusso et al [20] with the same staining procedure also found no significant difference of luminance between control and overfed Muscovy ducks. Inside the fibres, the proportion of phospholipids is Figure 3.…”

“…accumulated first in the liver but also in peripheral tissues such as adipose tissues and muscles [6][7][8]. Accordingly, the lipid content of muscles increased [8,20]: 1.3 to 2.1 fold depending on muscle type and genotype. We observed a large increase in the relative surface occupied by adipocytes on muscle sections: 1.5 fold in P. major and 2.1 fold in Sartorius across genotypes.…”

“…During overfeeding, the growth of P. major is reduced or stopped [18,19]. In the Muscovy duck, Zanusso et al [20] also showed that the CSA of muscle fibres is not significantly influenced by overfeeding. As Zanusso et al [20], we found that the composition of fibre type of muscles was not modified by overfeeding.…”

Responses to nutrients in farm animals: implications for production and quality

“…Generally speaking, the muscle tissues adapt their energy metabolism to overfeeding, increasing their oxidative metabolism, and decreasing their glycolytic metabolism, particularly in breast muscle (Zanusso et al, 2003;Chartrin et al, 2006). It has been hypothesised that muscle tissues adapt their metabolism to use more fat as the energy source following overfeeding due to greater fat availability (as demonstrated by higher TG levels in the plasma) and reduce their utilisation of glucose (Chartrin et al, 2006).…”