Danuta Michalik

Effect of body weight on the carcass composition of French Lop rabbits

The experiment was performed on 60 male French Lop rabbits reared under extensive conditions and sacrificed at body weights of approximately 3 kg at the age of 150 d (30 animals) and approximately 4.5 kg at the age of 210 d (30 animals). Chilled carcasses without heads were divided into the front, middle and hind sections, which were then dissected to separate lean meat (including intramuscular fat), fat and bones. An increase in the body weight of rabbits at slaughter was accompanied by a decrease, of about 0.60%, in the proportion of the head and giblets (kidneys, liver, heart and lungs) in the carcass, and by an increase in the perirenal fat content from 0.66 to 1.69%. The average carcass dressing percentage of rabbits sacrificed at an average body weight of 3054 g reached 49.13%, and it was 2.49% higher than in rabbits slaughtered at a body weight of 4427 g. The percentage content of the front, middle and hind sections of the carcasses of the lighter rabbits was 38.50, 21.76 and 39.74%, respectively. ...

Use of a modified skin slice with subcutaneous fat and carcase weight without this slice for prediction of meatiness and fatness in young slaughter geese

1. White Italian geese (40 males and 40 females) were reared until 12 weeks of age and fed standard diets ad libitum. After rearing ended, the geese were weighed (males–5216 g, females–4945 g) and killed. Carcases were chilled and skin slices with subcutaneous fat removed. The remaining part of the carcase was dissected into meat, intermuscular fat and bones. 2. The weight of a skin slice with subcutaneous fat, taken from the carcase surface excluding the forewings and wing tips (X 2), and the weight of a carcase excluding this slice, the forewings and wing tips (X 1) were very good indicators of the content of skin with fat (r > 0·99) and meat (r > 0·98) in a whole carcase. 3. The above traits provided a basis for deriving regression equations to estimate the content of meat (Ŷ) or skin with subcutaneous and intermuscular fat (Û) in whole carcases of White Italian geese. The following equations are recommended for practical application: Ŷ = 0·755X 1 – 27·8 (Sy  = 26·3 g); Û = 1·070X 2 + 19·5 (Su  = 11·4 g)

Carcass characteristics, meat quality, and fatty acid composition of wild-living mallards (Anas platyrhynchos L.)

Abstract The aim of this study was to determine the carcass characteristics, meat quality, and fatty acid composition of wild‐living mallards. The experimental materials comprised 30 mallards (1:1 sex ratio) harvested during the hunting season in northeastern Poland. The carcasses were transported to the laboratory where they were weighed individually, plucked, dressed, and dissected. The proximate chemical composition and physicochemical properties of meat and the fatty acid profile of breast muscle lipids were determined, and a histological analysis was performed. Body weight (BW) and carcass weight were higher in males than in females (P ≤ 0.05), whereas the percentage share of carcass tissue components was similar in both sexes. Edible components accounted for approximately 60% (♂) to 60.7% (♀) of the total BW of mallards, including lean meat; 40.9% (♂) to 41.5% (♀), skin with subcutaneous fat; 10.7% (♂) to 10.8% (♀), and giblets; 8.3% (♂) to 8.4% (♀). Breast muscles had high protein content (23.51%♀ to 23.6% ♂) and low fat content (0.82% ♂ to 0.84% ♀). In the fatty acid profile of breast muscle lipids, saturated fatty acids (SFA) accounted for 39.1% (♂) to 39.04% (♀), monounsaturated fatty acids (MUFA)—for 17.31% (♂) to 17.33% (♀) and polyunsaturated fatty acids (PUFA)—for 43.61% (♀) to 43.64% (♂). The diameters of type IIA and type IIB muscle fibers were lower in males than in females (P ≤ 0.05), whereas lipid storage sites in muscles were similar in both sexes. The values of cooking loss (CL), water‐holding capacity (WHC), pH24, and color parameters of breast meat were comparable in males and females. The results of this study indicate that wild‐living mallards, both males and females, are characterized by high meat quality, and that seasonal mallard harvests can provide meat with desirable eating attributes, attractive to consumers.

Effect of genotype, sex and age on plumage maturity, and body weight of guinea fowl (Numida meleagris).

Abstract The objective of this study was to investigate the effect of genotype and sex on the degree of maturity of the plumage of guinea fowl. The experimental materials comprised 300 slow-growing (Label group) and 300 fast-growing (Standard group) gray guinea fowl. At 12, 14 and 16 weeks of age, 12 birds from each group (six ♂ and six ♀) were slaughtered. Dry feathers were collected from the dorsal area on both sides of the spine, in the interscapular and thoracic region, and from the outer side of the left thigh. The percentages of feathers at five stages of development were determined for each bird: I - pinfeathers covered in sheaths, II - beginning of vane development, III - feathers unsheathed by half of rachis length, IV - feathers unsheathed by more than half of rachis length, V - fully developed vanes and afterfeathers. Feather weight was determined and expressed as a percentage of a bird’s total body weight. At 12 weeks of age, guinea fowl were characterized by the lowest (68.23%) percentage of mature feathers. The percentage of mature feathers increased to 79.36% in week 14 and to 83.20% in week 16. In weeks 14 and 16, the proportion of feather weight in total body weight was significantly lower (9.95 and 10.20%, respectively) than in week 12 (11.88%). Genotype had no effect on feather development, but it influenced feather weight and percentage. Significant (P<0.05) genotype × sex × age interactions were observed in percentage of stage I feathers. Label group guinea fowl were characterized by higher feather weight and a higher proportion of feathers in total body weight than Standard group guinea fowl (267.0 g and 11.01%, 248.9 g and 10.34%, respectively). The percentage of feather weight was lower in females than in males.