This study examined the effects of supplementation of dietary sodium selenite and sodium enriched alga Chlorella on growth performance, selenium concentration in breast meat and excreta, activity of glutathione peroxidase in meat, and oxidative stability of meat in broilers. Sexed broiler cockerels Ross 308 were allotted to 3 dietary treatments, each comprising 100 chickens. The basal diet was supplemented with 0 (control) or 0.3 mg/kg Se from sodium selenite (SS) or Se-Chlorella (SCH). Dietary supplementation with SCH increased (P < 0.05) body weight. The breast muscle Se concentration was increased (P < 0.05) by SCH (0.70 mg/kg DM; 0.36 mg/kg DM in control) supplementation, but not (P > 0.05) by SS (0.49 mg/kg DM) supplementation. The concentration of Se in excreta was highest in the SS group. The activity of GSH-Px in breast meat was significant P < 0.05) in all treatments (0.16 U/g in control, 0.30 U/g in SS and 0.23 U/g in SCH group). The inclusion of SCH in the diet enhanced the oxidative stability of meat expressed as reduced malondialdehyde (MDA) values in breast meat after 0; 3 and 5 days storage in refrigerator at 3 to 5°C.

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.

Forty rabbits weaned at 35 d of age were randomly assigned to 4 groups of 10 rabbits each. The rabbits were fed a basal granulated diet containing 0.08 mg Se/kg, or diets obtained from basal diet, supplemented with sodium selenite, selenized yeast (Se-yeast) or selenized algae Chlorella (Se-algae) to increase the Se concentration to 0.40 mg/kg. After 6 weeks rabbits were slaughtered at 77 d of age. Samples of meat, liver and hair were analyzed. The Se supplements did not infl uence rabbit growth, feed intake and weight loss during cooling. The nutrient composition of meat (dry matter, protein and fat concentration) was only marginally infl uenced. The Se concentration in the loin and hindleg meat increased by 23.0% and 19.2%, respectively in rabbits receiving the selenite supplement. In rabbits fed Se-yeast and Se-algae, the Se content in meat doubled from 0.11-0.15 mg/kg to 0.24-0.29 mg/kg. High Se concentrations (=1 mg/kg) were observed in hair and liver of rabbits which had received the Se-supplements. In all supplemented groups, the activity of glutathione peroxidase in the loin meat was higher than in control rabbits by 51.9-72.8% (P<0.001). The oxidative stability of rabbit meat, however, was not infl uenced. It follows from our results that (i) the enrichment of meat with Se is the main benefi t of supranutritional Se supply in rabbits, and (ii) Se-yeast and Se-algae are more effective in increasing Se content in tissues than selenite.

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In this study the deposition of dietary CLA isomers in loin and hindleg meat, liver and fat, and the influence on performance and fatty acid (FA) profile were investigated in growing rabbits. CLA was supplied as synthetically produced oil at 5 and 10 g/kg diet for the whole fattening period (six weeks) or three weeks before the slaughter. CLA had no or limited effect on feed intake, growth, carcass traits and composition of meat. Treatment with CLA increased the proportion of saturated FA at the expense of monounsaturated FA in meat and liver. Supplementation of the diet with CLA increased (<I>P</I> < 0.05) CLA in lipids of meat from < 1 mg/g FA up to 36 mg/g FA. Adipose and hepatic tissue incorporated the highest (44 mg/g FA) and the lowest (14 mg/g FA) amount of CLA, respectively. The concentration of CLA in tissue lipids increased (<I>P</I> < 0.05) with increasing CLA content in the diet. Duration of CLA feeding had no effect on CLA deposition. Thus, dietary inclusion of CLA at higher concentration (10 g/kg) and feeding CLA-supplemented diet for a shorter period seems to be more suitable for production of CLA-containing rabbit meat. The ratio of the two most abundant isomers of CLA,<I> cis</I>-9, <I>trans</I>-11 and <I>trans</I>-10, <I>cis</I>-12 in tissues differed from that in the CLA-enriched diet. In all tissues the relative proportion of the former isomer was lower than in the diet. The experiment demonstrated that feeding synthetic CLA to rabbits is a means of enriching rabbit meat with CLA, which could provide a healthier product for human consumption.