New selenium-enriched fodder yeasts and their application in rations of laying hens

Abstract

The aim of the present investigation is the comparative evaluation of the effect of sodium selenite and Se-enriched fodder yeasts on productivity of laying hens and egg quality. Using a novel microbial strain Candida stellimalicola 4-ASe, the first in Belarus pilot-scale technology of manufacturing fodder yeast fortified with selenium was elaborated. A test batch of the new feed product containing 2000 mg Se / kg was produced and passed successful large-scale trials. It was found that introduction into the rations of both sodium selenite and selenium-enriched yeast did not significantly affect viability and productivity of laying hens. However, addition into chiken feed formulas of selenium-enriched yeast (200 and 300 mg Se / t of composite fodder) in contrast to sodium selenite supplement (200 mg Se / t) improved morphological characteristics (Hough unis, albumen and yolk indexes, shell thickness) and raised protein ratio in eggs as well as concentrations of vitamin A and carotenoids. Moreover, in laying hens nourished with selenium-enriched yeast, the yield of small and second category eggs tended to decrease with concomitant rise in the share of eggs representing the first (from 23.7 to 31.1–33.1%), premium (from 0.3 to 0.6%) and supreme (from 0 to 0.3–0.6%) categories. Scaling up the process of manufacturing Se-containing feed additives based on a novel yeast strain Candida stellimalicola 4-ASe will enable to broaden the range of fodder commodities launched onto the market. Their applications relying on the analyses of biochemical blood tests, examination of intestinal microbiota of laying hens, efficiency of selenium incorporation in eggs, will promote enhanced yields, quality and profitability of poultry products, fabrication of foodstuffs preventing diseases provoked by selenium deficiency.