Resumen
This study aimed to evaluate how different percentages of guar meal in feed rations for broiler chickens affect their rearing performance and carcass composition. The experiment was conducted in a group of one hundred sixty Ross 308 broilers randomly allocated to four equinumerous groups (K, G4, G8 and G12). The birds were reared over 42 days with the application of three feeding periods: starter (days 1?21), grower (days 22?35) and finisher (days 36?42). All the feed rations were prepared using maize meal, soybean meal, oil and mineral and vitamin additives. An experimental factor was the share of guar meal in feed rations: group K?0%, G4?4%, G8?8% and G12?12%. It was demonstrated that a higher percentage (8% or 12%) of guar meal in the feed rations had a negative effect on the chickens? weight gain and feed intake. The birds receiving feed rations supplemented with guar meal featured higher feed conversion levels than those fed rations in which soybean meal was the only protein-rich component (p = 0.05). Birds fed rations with the highest percentage (12%) of guar meal showed a significant decrease in chilled carcass weight and dressing percentage compared with other chickens. A higher percentage (8% or 12%) of guar meal in feed rations had an adverse effect on the birds? muscularity. In addition, it was demonstrated that their meat was DFD (dark, firm and dry; pH1 > 6.4), but from a dietary point of view, it contained the smallest amount of intramuscular fat. To sum up, 4% of guar meal should be recommended in broiler chicken feeding to ensure their satisfactory rearing performance and carcass composition, including the physico-chemical properties of their muscles.