Effect of sex on growth, biochemical and haematological parameters of blood, carcass value and meat quality in nutrias (Myocastor coypus)

Sex differences in growth, blood indicators, carcass values and meat quality in nutrias were evaluated. In the fattening experiment, 136 nutrias of both sexes (1 : 1 ratio) were fattened until 8 months of age. At the end of the experiment, 18 males and 18 females with average weights were selected for the determination of biochemical indicators, carcass value and meat quality. The growth of males was significantly higher than in females; the differences were 12% at three months of age and increased to 24% at eight months of age. The effect of sex on the biochemical indicators of blood was observed in total protein (P ≤ 0.029), albumin (P ≤ 0.012), urea (P ≤ 0.019) and cholesterol (P ≤ 0.026), with higher values in males. In the case of haematology examination, the significantly higher values in males were in the number of erythrocytes (5.10 × 1012/l) and in the haematocrit value (55.8%). Dressing out percentage was higher in males (P ≤ 0.039), and other parameters of carcass value were not affected by sex. For the meat physical properties, only lightness (P ≤ 0.019) was higher in males. In the case of the chemical composition of meat, ether extract (P ≤ 0.033) and energetic value (P ≤ 0.024) were lower in females. The results of this study show high differences in the growth of male and female nutrias, whereas carcass composition, physical meat quality and meat chemical composition are less affected by nutria sex.