Effects of Dietary Probiotics on Performance, Egg Quality and Yolk/Serum Cholesterol of Laying Hens
In an experiment with 112 laying hens from a commercial strain (Hy-line W36), the effects of probiotics Biosaf SC 47 (SC) containing a minimum of 5×109 colony forming units (cfu) g 1 Saccharomyces cerevisiae (strain NCYC Sc 47) and BioPlus 2B (BP) containing a minimum of 3.2×109 cfu g 1 of Bacillus licheniformis (strain CH200) and B. subtilis (strain CH201) on performance, egg quality and yolk/serum cholesterol was determined. In the 10 week experiment, hens (46 to 55 weeks of age) were allocated to seven dietary treatments being: SCBP0, SC200, SC300, SC400, BP400, BP800 and BP1200 of 16 birds each and received a diet ad libitum. The diet for SCBP0 treatment had no probiotic (control), while those for treatments SC200, SC300 and SC400 included 200, 300 and 400 g t 1 of probiotic SC, respectively and those for treatments BP400, BP800 and BP1200 included 400, 800 and 1200 g t 1 of probiotic BP, respectively. Inclusion of the probiotics SC at levels up to 400 g t 1 and BP at levels up to 1200 g t 1 in diets of laying hens resulted in similar traits, relative to final BW, DFC, egg weight, egg mass, egg shell breaking strength, haugh units, albumen index, yolk color, and yolk and serum cholesterol. Egg production and egg shell weight did not differ (p>0.05) between treatment SCBP0 and all other treatments, but egg production was higher (p<0.05) in treatment SC400 compared to treatment BP1200 and egg shell weight was higher (p<0.05) in treatments SC300, SC400, BP800 and BP1200 compared to treatment BP400. Feed efficiency was higher (p<0.05) in treatments SC200, SC300 and BP800 compared to treatment SCBP0 and egg shell thickness was higher (p<0.05) in treatment SC200 compared to treatments SCBP0 and BP400, whilst no other differences were observed among treatments. No deaths occurred during the experiment.