ABSTRACT
BACKGROUND: The effects of humic substances (HS) on quality traits (colour, water-holding capacity, and pH) of breast and thigh meats and on blood minerals (calcium and phosphorus) and on metabolites (glucose, total protein, triglyceride and cholesterols) as well as on the performance, carcass, and gastrointestinal tract (gut) traits of broilers were studied. In total, 480 male chicks (ROSS 308) were allocated to four treatments, each with five replicates containing 24 birds. While control birds were fed a diet (mash form) with no additives (0 HS), other treatment birds were fed with diets containing HS at 0.5 (0.5 HS), 1.0 (1 HS) or 1.5 (1.5 HS) g kg(-1) from 1 to 42 days of age. RESULTS: The body and carcass weights and feed efficiency increased (P < 0.05) by 1.5 HS, and blood cholesterol decreased (P < 0.05) by 1 HS and 1.5 HS compared to 0 HS. The 0.5 HS decreased (P < 0.10) low-density lipoprotein compared to 0 HS. The 0.5 HS resulted in thigh meat and breast meat that were lighter and darker than those found in the other groups and 1.5 HS respectively (P < 0.01). CONCLUSION: Feeding with a diet containing HS caused a measurable variation in the meat quality and blood cholesterol as well as the performance, carcass, and gut traits of broilers.
