the aim of the study was the comparison of the physicochemical and sensory characteristics of capons and cockerels. the experiment involved 80 rhode island red (r-11) cockerels, which were randomly assigned to two groups with 40 birds per group. Group i (control) consisted of uncastrated cockerels, and group ii was comprised of birds subjected to castration at 9 weeks of age. the castration was performed under local anaesthesia by a veterinary surgeon. the birds received the same diets ad libitum and were kept on litter under optimal environmental conditions, at a stocking density of 7 birds/m 2 . at the end of fattening, 8 birds whose body weights were similar to the group average were selected for slaughter from each group. after slaughter, the birds were checked for castration success (removal of the testes), analysed for dressing percentage and technological parameters of the meat and subjected to chemical and sensory evaluation of the breast and leg muscles. in summary, the castration of rhode island red cockerels (r-11) had a favourable effect on body weight, feed conversion ratio, dressing percentage and carcass muscling. the breast and leg muscles of the capons were characterised by better water holding capacity, tenderness and sensory score compared to the uncastrated cockerels. in addition, the castration had a positive effect on the content of crude protein in both the breast and leg muscles which, with a higher crude fat content, were characterised by a more favourable profile of fatty acids, i.e. lower sfa and higher n-6 and n-3 pUfa content.Key words: capon, meat quality, fatty acid, sensorial evaluation, spme-GC-ms, chemometricsAccording to the Codex Alimentarius FAO/WHO, meat quality is defined as a combination of attributes that meet specific demands and make meat desirable for food. Over the last several years there has been an increasing number of consum-*This study was financed from statutory activity, project no. 03-010.01.

the aim of the study was to assess the quality of carcasses and meat from selected native breeds and breeding lines of hens after using them for laying eggs in terms of their usefulness as raw material in traditional old polish cuisine. hens included in the programme for the protection of genetic resources were the object of this study. they belonged to the following breeds/breeding lines: greenleg partridge (Z-11), rhode Island red (r-11), new hampshire (n-11) and Barred rock (WJ-44) -30 hens from each line. the hens were kept in a closed hen house under standard raising conditions. eight hens were selected from 56-week-old hens of each line which were subjected to analysis after being slaughtered. as a result of the research conducted, it was found that: -among the hens under study, heavier layers, i.e. Barred rock (WJ-44), new hampshire (n-11) and rhode Island red (r-11), which are characterized by good muscling and dressing percentage similar to that of broiler chickens, proved to be most suitable for use as meat. -the meat from WJ-44 hens contained most cholesterol and least protein, and the meat from Z-11 birds had the least fat compared to the other lines. -at the end of the laying period, meat and broth from WJ-44, n-11 and r-11 hens obtained better sensory scores than those from the carcasses of Z-11 hens, which makes them an attractive raw material for traditional polish cuisine.

1. A total of 192 ISA Brown hens were given diets containing a high concentration of maize dried distiller's grains with solubles (DDGS) and the effect of selected feed additives on laying performance and egg quality was determined. 2. Birds were allocated to 8 treatment groups with 12 replicates (cages) of two hens and were given, from week 26 to 55, iso-caloric and iso-nitrogenous experimental diets with or without a high concentration of DDGS (200 g/kg). The diet containing DDGS was not supplemented or supplemented with enzymes (xylanase and phytase), sodium butyrate, probiotic bacteria (Lactobacillus salivarius) and a mixture of herbal extracts (Taraxaci siccum, Urticae siccum and Salviae siccum), inulin or chitosan. 3. The inclusion of DDGS in the diet had no effect on number of eggs produced, total egg mass, mean egg weight, feed intake or feed conversion ratio. Egg and eggshell quality parameters were also unaffected by dietary DDGS. The yolk colour score (points in Roche scale) was significantly increased by DDGS inclusion. DDGS in the diet caused some changes in the yolk lipid profile that were rather unfavourable from a dietary perspective (an increase of cholesterol content, and PUFA n-6/PUFA n-3 ratio). 4. During the experimental period (26-55 weeks of age) supplementation of the diet containing a high concentration of DDGS with enzymes, inulin as well as chitosan, increased number of eggs produced and daily egg mass. In older hens (50 weeks of age) inulin positively affected eggshell quality parameters, i.e. shell percentage, thickness and density. Diet supplementation with herb extracts, inulin or chitosan, decreased the content of cholesterol in yolks. 5. The results of this study suggest that DDGS may be incorporated up to a concentration of 200 g/kg in the diet of laying hens without any negative effects on egg performance. Moreover, supplementation of xylanase and phytase, as well as inulin and chitosan, can positively affect the performance of layers given diets with a high concentration of DDGS.

Abstract. The objective of this study was to evaluate the effect of particle size of a dietary Ca source on egg production and eggshell quality when added to hens' diets that have different levels of calcium. The experiment was carried out on 216 ISA Brown hens (25 to 70 weeks of age), allocated to 9 groups of 12 replicates (cages), with two birds in each cage. A 3 × 3 factorial arrangement was used, with three dietary levels of calcium (3.20, 3.70 and 4.20 %) and three levels of dietary substitutions (0, 25 and 50 %) of fine particles of limestone (FPL, diameter 0.2-0.6 mm) with large particles of limestone (LPL, diameter 1.0-1.4 mm) as a Ca source.The level of Ca in the diet had no effect on egg production, mean egg weight, feed intake, feed conversion ratio or eggshell quality parameters (P >0.05). Substitution of FPL with LPL did not affect laying performance indices or eggshell quality at 30, 43 and 53 weeks of age (P >0.05); however, it increased (P <0.05) eggshell percentage, thickness, density and breaking strength in older hens (69 weeks of age). In conclusion, the results of this study demonstrated that a level of 3.20 % Ca in a layer's diet is sufficient through the entire laying cycle to maintain good egg production and eggshell quality and that partial (25 or 50 %) substitution of fine-with large-particle limestone can, irrespective of the level of Ca in the diet, improve eggshell quality in aged laying hens.

the aim of the experiment with 240 isa Brown hens fed the diets with standard or decreased ca level was to evaluate the effect of selected feed additives on laying performance and eggshell quality. the hens were allocated to 10 treatments, each containing 12 cages (replicates) of 2 birds. a 2 × 5 experimental arrangement was used. from 26 to 70 wks of age, experimental diets containing 3.20 or 3.70% ca were used. the diets were either not supplemented, or supplemented with sodium butyrate, probiotic bacteria, herb extracts blend or chitosan. the decreased dietary ca reduced eggshell quality indices in older hens (43-69 wks) (p<0.05) without effect on performance indices. the addition of the probiotic, herb extracts, or chitosan increased the laying rate (p<0.05). in older hens, i.e. at 69 wk, chitosan increased eggshell thickness and breaking strength, while herb extracts increased eggshell thickness (p<0.05). there was no interaction between the experimental factors in performance and eggshell quality. The used feed additives had no influence on fatty acid profile of egg lipids, however diet supplementation with chitosan decreased cholesterol concentration in egg yolk lipids (p<0.05). it can be concluded that such feed additives as probiotic, herb extracts, or chitosan may positively affect performance and eggshell quality, irrespective of ca dietary level.