The nutrient retention and carcass quality of Noiler chickens fed diets containing supplemental levels of saccharomyces cerevisiae
The present study evaluated the effects of graded dietary inclusion of Saccharomyces cerevisiae on nutrient retention and carcass characteristics of Noiler chickens under tropical production conditions. A total of 300 day-old Noiler chicks of mixed sexes were randomly allocated to five dietary treatments in a completely randomised design, with three replicates of 20 birds per treatment. The treatments comprised a basal diet without yeast (T1) and diets supplemented with 0.5% (T2), 1.0% (T3), 1.5% (T4) and 2.0% (T5) S. cerevisiae. The feeding trial lasted 16 weeks. Apparent nutrient retention was determined during the finisher phase using acid-insoluble ash as an internal marker, while carcass evaluation was conducted at the end of the trial on representative birds per treatment. Dietary yeast supplementation significantly (P < 0.05) influenced dry matter, moisture, ash, ether extract, crude fibre, nitrogen retention and apparent metabolisable energy. Birds fed 1.5% S. cerevisiae (T4) recorded the highest nitrogen retention (43.58%), whereas mineral retention was optimised at 1.0% inclusion (17.78%). Apparent metabolisable energy was highest in the control group but remained comparable among supplemented treatments. Crude protein digestibility showed slight numerical improvement in yeast-fed groups without adverse effects, indicating that supplementation up to 2% did not impair protein utilisation. Improvements in fibre utilisation and mineral retention suggest enhanced digestive efficiency and gut functionality in supplemented birds. Carcass characteristics revealed no significant (P > 0.05) differences in live weight, dressed weight, breast yield or back cut among treatments, although numerical improvements were observed at 0.5% and 2.0% inclusion levels. Significant (P < 0.05) differences were detected in thigh, drumstick and shank weights, with the 2.0% inclusion level producing superior drumstick (195.67 g) and shank (84.67 g) weights, indicating enhanced development of locomotive muscles. The observed improvements in selective carcass traits may be associated with enhanced nutrient partitioning, improved mineral bioavailability and better intestinal integrity mediated by yeast cell wall components such as β-glucans and mannan-oligosaccharides. Overall, dietary supplementation of Saccharomyces cerevisiae enhanced nutrient retention and improved selected carcass parameters of Noiler chickens without detrimental effects on growth or carcass yield. Inclusion levels between 1.0% and 1.5% optimised nutrient utilisation, while 2.0% favoured certain muscle traits. These findings provide breed-specific evidence supporting the strategic use of probiotic yeast as a functional feed additive to improve productivity and sustainability of dual-purpose chickens under tropical production systems.
Keywords: Noiler chickens; nutrient retention; probiotic yeast; carcass traits; tropical poultry production; Saccharomyces cerevisiae.
