No abstract

Feedstuffs are routinely supplemented with various selenium sources, where organic forms of Se are more bio-available and less toxic than the inorganic forms (selenites, selenates). When the algae are exposed to environmental Se in the form of selenite, they are able as other microorganisms to incorporate the element to different levels, depending on the algae species. Technology of heterotrophic fed-batch cultivation of the microalga Chlorella enriched by organically bound Se was developed, where the cultivation proceeds in fermentors on aerated and mixed nutrient solution with urea as a nitrogen and glucose as a carbon and energy source. High volumetric productivity and high cell concentrations (about 70-100 g Chlorella dry mass l(-1)) can be attained if nutrients and oxygen are adequately supplied. Addition of a small quantity of a new selenoprotein source-spray-dried Se-Chlorella biomass to the diet of farm animals had better effects on specific physiological and physical parameters of animals than selenite salt and was comparable with Se yeast added to the diet. This review introduces the importance of selenium for humans and animals, methods of Se determination, heterotrophic production of selenium-enriched Chlorella biomass in a fed-batch culture regime on organic carbon, and use of the biomass in animal nutrition.

ABSTRACT:The present study investigated the effect of 1 and 2% feed supplementation with biomass of Chlorella grown through heterotrophic fermentation on the concentration of total and individual carotenoids in egg yolks. A total of twenty-four Hisex Brown laying hens aged 56 weeks were included in the experiment. The layers were kept individually in cages. They were divided into three groups of eight birds and fed a diet typical for laying hens. Control birds (C) received only a basal diet, while experimental diets (P1 and P2) were supplemented with 1 and 2% (i.e. 10 and 20 g/kg) dry disintegrated Chlorella biomass. Egg yolk deposition of total carotenoids was significantly (P < 0.01) increased by 46% (P1) and 119% (P2). The rising curves of total carotenoids reached their plateau during the fourth experimental week. The respective values oscillated around 25 mg (P1) and 40 mg (P2) per g of yolk during the following weeks. Lutein and zeaxanthin were equally deposited and they represented more than 90% of total carotenoids in yolk. The deposition of carotenoids significantly (P < 0.01) increased the colour characteristics of yolks measured using the Roche Yolk Colour Fan scale. Supplementation with Chlorella biomass significantly decreased the egg yolk weight of P2 in comparison with P1 (P < 0.05) and C (P < 0.01). These effects were probably related to lower feed consumption in these hens. The daily feed intake per hen, as well as its consumption per egg, was lower by 5-7 g in both supplemented groups. Recalculation of the diet consumption per kg of egg and yolk mass eliminated these differences. There were no differences among laying hens in plasma concentrations of triacylglycerol and cholesterol.

The aim of this study was to evaluate the effect of organic Se from Se-enriched alga (Chlorella spp.) and Se from Se-enriched yeast on concentrations of Se in serum and tissues, and serum GSH-Px activities and carcass characteristics in finishing pigs.The pigs were on experimental diets for a period of 3 months before slaughter with different Se supplements at the concentration of 0.3 mg Se per kg of feed. In group I (n = 12) the feed was supplemented with inorganic sodium selenite; in group II (n = 12) with organic Se from Se-enriched yeast; in group III (n = 12) with organic Se from Se-enriched alga, Chlorella spp. and pigs in group IV (n = 11) received a non-supplemented basal diet. The organic Se sources did not differ in serum Se and serum GSH-Px activities. Significantly higher Se concentrations in muscle (P < 0.01) and in the heart (P < 0.01) were found when Se from Se-enriched yeast was given, compared to the group of pigs that received Se from Se-enriched alga Chlorella spp. The Se content in livers and ovaries did not differ between the two organic Se sources. The use of both organic Se forms resulted in a higher accumulation in muscle tissue compared to the inorganic Se form. No differences in meat quality characteristics were found among the experimental groups. It is concluded that Se from Se-enriched alga, Chlorella spp. had a lower accumulation in muscle tissue than Se from Se-enriched yeast, and it did not affect meat quality.Glutathion peroxidase, GSH-Px, pork, meat quality, sodium selenite

The study was conducted to determine the efficacy of organic Se from Se-enriched alga Chlorella spp. in placental transfer to piglets. In group A (n = 8) the sows were fed during the gestation a diet supplemented with inorganic Se (sodium selenite, 0.3 mg/kg). In group B (n = 8) the diet of the sows was supplemented with organic Se from Se-enriched alga (0.3 mg/kg). The Se concentrations in the whole blood (P < 0.05) and in colostrums (P < 0.05) were higher in the group of sows provided with the organic Se form. No differences in GSH-Px activities were found between the two groups. The concentrations of Se in piglet tissues were also higher when the organic form was provided. It is concluded that the use of the organic Se from Se-enriched alga Chlorella spp. in sows resulted in greater transfer of Se to their progeny.