Activities of twelve hydrolytic enzymes in the digestive tract of young rabbits before weaning (4 weeks old) and adult rabbits (3 months old) were measured. The principal digestive enzymes in both groups of rabbits appeared to be amylase (EC 3.2.1. l), maltase (EC 3.2.1.20), pectinase (EC 3.2.1.15) and proteinases. The stomach of young rabbits contained most of the lipolytic activity and 45.7 YO of the total proteolytic activity of the digestive tract. The highest specific activities (per g digesta) of amylase, maltase and proteinase in young rabbits were found in the small intestine. Total activities (per segment) of amylase and maltase in the small intestine and the caecum were similar. Activities of cellulase (EC 3.2.1.4), inulinase (EC 3.2.1.7) and pglucosidase (EC 3.2.1.21) were low and activity of pectinase was fairly high in all segments of the digestive tract. The highest activity of urease (EC 3.5.1 -5) was found in the caecum. Enzymic profiles of the colonic chymus resembled those of the caecum. Total hydrolytic activity was lower in the colon than in the caecum. Specific activities of amylase and invertase (EC 3.2.1.26) were lower and those of inulinase and lactase (EC 3.2

An experiment was conducted to evaluate the effect of dietary content and combinations of Zn, Fe, and Cu on deposition of these elements in egg components, liver, and excreta. Excreta were applied as a manure to a lawn, and 3 mo later soil and herbage samples were taken and analyzed. The experiment comprised 144 hens in 8 groups. The basal diet contained Zn, Fe, and Cu at 63.4, 92.8, and 9.0 mg/kg, respectively. It was supplemented with 1, 2, or 3 trace elements (inorganic forms) at 80 mg of Zn/kg, 120 mg of Fe/kg, and 25 mg of Cu/kg. Recovery of Zn, Fe, and Cu in eggs of hens fed the basal diet was 10.7, 9.8, and 4.4% of the alimentary intake, respectively. A Zn-Cu antagonism was observed; deposition of Zn in the yolk was significantly decreased by Cu addition and vice versa (P < 0.01). Supplementation of the basal diet with Fe increased Fe concentration in egg yolk and white by 6.3 and 2.2%, respectively. The combination of Fe with Zn and Cu, however, increased Fe concentration in the yolk and white by 36.7 and 34.9%, respectively (P < 0.01). The enrichment of eggs with the other elements was marginal (Cu) or absent (Zn). Effects of Zn, Fe, and Cu of the basal diet on liver concentrations of these elements were relatively small, and no antagonism between Zn and Cu was apparent. Supplementation of the basal diet with the combination of Zn and Fe, however, significantly decreased hepatic concentration of Cu. On the other hand, Cu supplementation significantly increased Fe concentration in livers of hens fed the Fe-supplemented diet (P < 0.01). Concentrations of Zn, Fe, and Cu in excreta were related to their dietary content. High concentrations of Zn, Fe, and Cu in excreta corresponded with limited deposition of the 3 elements in eggs and liver. Concentrations of Zn, Fe, and Cu in herbage correlated significantly with the supply of these elements by hen excreta into soil. The Zn supplied by hen excreta was more stable than Fe and Cu; thus Zn could accumulate in the soil.

Ten weaned rabbits were fed a basal (control) diet containing 0.12 mg Se/kg. In 10 rabbits the basal diet was supplemented with Se-enriched yeast to increase the Se concentration to 0.50 mg/kg. Rabbits were slaughtered at the age of 11 weeks. Samples of meat, liver and hair of 4 rabbits from each group were taken and analyzed. No effect of Se on growth, feed conversion and dressing out percentage was observed. Loin and hindleg meat, liver and hair of control rabbits contained 93, 98, 521 and 267 μg Se/kg, respectively (average values). In treated rabbits the corresponding Se concentrations were 400, 389, 1 414 and 914 μg/kg. Supranutritional Se supply had no effect on the activity of glutathione peroxidase in meat, and oxidative stability of meat expressed as production of thiobarbituric acid-reactive substances in meat stored for 3 and 6 days. Thus, the enrichment of meat with Se is the main benefit of Se supplementation of rabbit diets.

ObjectiveThe aim of this study was to compare carcass traits, meat quality and sensory attributes in two different genotypes of geese according to age and sex.MethodsThe experiment was carried out on 160 birds of two genotypes of geese: the Czech Goose (CG) breed and a Eskildsen Schwer (ES) hybrid. One-d-old goslings were divided into four groups according to genotype and sex. Two dates for slaughtering (at 8 and 16 wk of age of goslings) were undertaken.ResultsThe slaughter weight, cold carcass weight and dressing percentage were affected by all the studied factors, and significant interactions between age, genotype and sex were detected in the slaughter weight (p<0.001) and cold carcass weight (p = 0.004). The pH was not affected by any of studied factors, whereas in terms of meat colour parameters there were observed significant effects of age on L* and b* value and a significant effect of sex on a* value. The meat fat content was higher (p = 0.002) in ES. Higher score for overall acceptance of goose meat was recorded for ES at both ages compared to CG.ConclusionES had higher dressing percentage and better sensory attributes, whereas CG exceled in the favourable nutritional value of the meat.

1. Three hundred and twenty d-old chickens were fed on a wheat/maize-soyabean meal diet supplemented with (i) 50 g/kg lard, (ii) 25 g/kg lard and 25 g/kg rapeseed oil, (iii) 50 g/kg rapeseed oil, and (iv) 50 g/kg rapeseed oil and 200 mg copper per kg as copper sulphate pentahydrate. 2. Final weights at 39 d of age in chickens receiving rapeseed oil were lower by 9% than in those fed on the diet containing only lard (P<0.05). The fatty acids profiles of lipids extracted from the tissues of 10 chickens per group reflected those of the diets. 3. The polyunsaturated fatty acid (PUFA) content of breast muscles and abdominal fat (expressed as a percentage of total fatty acids) was increased and the ratio of n-6:n-3 fatty acids was decreased by the substitution of lard by rapeseed oil (P<0.001). These changes were more pronounced for the adipose tissue than for breast muscles. 4. Copper sulphate supplementation increased the final body weight of chickens by 4.3% (P<0.05), reduced the saturated fatty acid (SFA) proportion (P<0.05) in abdominal fat and increased the PUFA:SFA ratio (P<0.05). The magnitude of improvement, however, was small. 5. The substitution of rapeseed oil for lard decreased the concentration of cholesterol in breast muscles by 13%. Copper supplementation further reduced the cholesterol content by 25%. Both effects were significant (P<0.001).

The effect of a dietary supplementation with mannan-oligosaccharide (MOS, Bio-Mos, Alltech Inc.) and inulin (Frutafit w IQ) on growth, health, and caecal traits was studied on 348 rabbits (Hyplus w ), weaned at 25 days of age. Three hundred and thirty rabbits (110 per group) were used for the health status and growth performance trial, while 18 rabbits (six per group) were used for caecal metabolism evaluation at the age of 42 days of age. Three diets were formulated: C (control), M (0.3% MOS) and I diet (4% inulin). Digestibility of the diets was measured in 10 rabbits per group between 36 and 40 days of age. The control diet was fed to rabbits of the C group from weaning to 74 days of age (slaughter). Diets M and I were fed to rabbits of the respective group from weaning to 46 days of age, then were fed with control diet till slaughter. From 25 to 46 days of age, the weight gain was slightly higher in control rabbits ( P ¼ 0.11), while no differences were recorded for the whole period. No differences among groups in the mortality, which was high due to an enteropathy-infected environment, were significant. The lowest morbidity ( P ¼ 0.05) as well as the health risk index were recorded in rabbits fed the diet with inulin ( P ¼ 0.03). After change of diet, the health risk index increased in the rabbits previously fed the diet with additives, thereby no significant differences in the health status were recorded for the whole period. Total caecal volatile fatty acids concentration was higher ( P , 0.01) and the pH ( P , 0.01) and ammonia concentration ( P ¼ 0.01) lower in rabbits fed the inulin diet than in other rabbits. In these animals, acetate molar proportion was higher ( P ¼ 0.01) and that of propionate as well as the propionate/butyrate ratio significantly lower than in other rabbits. Butyrate molar proportion was higher in rabbits fed the diet with MOS ( P , 0.01). In rabbits fed the inulin diet a higher activity of inulinase was recorded ( P , 0.001) than in other rabbits. A significantly lower digestibility of cellulose was observed in rabbits fed the diet with MOS. The results of our study suggest the importance of using inulin-type fructans in the nutrition of young rabbits. The higher health risk index of rabbits after change of diets indicates that prebiotics should be given for a longer time during the fattening period.

Copper is often added to poultry diets as an antimicrobial agent at doses greatly exceeding the nutritional requirement. In this study, the basal diet of laying hens containing 9.2 mg Cu/kg was supplemented with CuSO(4) x 5H(2)O at 0, 25, 65, 115, and 240 mg Cu/kg dry matter (DM). At Cu dietary concentration just below the level permitted by the European Union (35 mg/kg), the Cu content in the egg yolk was significantly (p < 0.05) increased by 26%, and nonsignificantly by 4.1, 9.1, and 7.9% in the egg white, eggshell, and liver, respectively. When Cu concentration in the diet was doubled, the effect of Cu on Cu content in eggshell and liver was statistically significant as well. In no liver sample was the hygienic limit of Cu content (80 mg/kg) exceeded. Supplementation of diets with Cu increased Cu concentration in excreta linearly from 25.3 to 396.8 mg/kg DM. Dried excreta were used for fertilization of grassland at 21 g N/m(2). Three months later, soil and herbage were sampled and analyzed. The Cu concentration in soil increased from 25.3 to only 46.4 mg/kg DM when dietary Cu concentration rose from 9.2 to 243.7 mg Cu/kg DM. Corresponding Cu concentrations in herbage were 6.8 and 19.2 mg/kg DM. It can be concluded that the deposition of Cu in eggs and liver of hens fed Cu-supplemented diets does not represent a hygienic risk. The accumulation of Cu in soil fertilized with excreta of Cu-fed hens and in herbage was limited.

In a search for alternatives of in-feed antibiotics, the antimicrobial activity of caprylic (C8:0), capric (CI 0:0) and oleic (C 18:1) acid was investigated in pure cultures of 19 strains of rumen and rabbit caecal bacteria, and in incubations of the rumen and rabbit caecal contents. In glucose-grown bacterial cultures the minimum inhibitory concentration (MIC) of caprylic acid ranged from 1 to 3 uTml 1. Two strains of Bacteroides ovatus were less susceptible to capric than to caprylic acid. In other strains, the MIC of capric acid was 0.25-0.50 uTml~!. The growth of most strains was not much affected by oleic acid. An exception to this were rumen bacteria Butyrivibrio fibrisolvens (MIC from < 0.05 to 1 uTml" 1) and Lachnospira multiparus (MIC of 0.25 to 1 uTml" 1). In incubations of the rumen and caecal contents caprylic and capric acid decreased the production of volatile fatty acids and gas, and increased production of lactate. In latter incubations the inhibitory effects of caprylic and capric acid were similar. In incubations of the rumen contents, capric acid was more efficient than caprylic acid when supplied at low concentrations (<1.25 uTml 1), but less efficient when supplied at 2.5 and 5 uTml" 1. Effects of oleic acid in rumen and caecal cultures were not significant, except the increase in production of lactate by rumen microorganisms. It can be concluded that microorganisms of the animal digestive tract are susceptible to inhibition by caprylic and capric acid added to microbial cultures at fairly low concentrations. Oleic acid was far less effective.