Abstract
The aim of this study is to evaluate the effects of dietary supplementation with acacia foliage, a tannin source, and feeding systems on Barbarine lambs' growth, carcass traits, and meat quality under grazing and feedlot conditions. Twenty-eight male lambs (5-month-old, 22.5 ± 3.6 kg) were divided into four groups based on body weight (BW) and assigned to one of four diets for a 60 d trial. Two groups were raised in stalls (S) and fed hay and concentrate, while two grazed on pasture (P) with the same concentrate supplementation. Within each system, one group received 100 g of
Acacia cyanophylla
daily (S-T, P-T), and the other did not (S-0T, P-0T). Pasture-fed lambs had higher total daily intake, average daily gain (ADG) and slaughter body weight than stall-fed lambs. Carcass weights and dressing percentages were also higher for grazing lambs. Tannin supplementation did not affect carcass traits or meat quality. Grazing lambs showed more developed red organs and higher fat deposition. Meat quality, including pH, color, chemical composition and sensory attributes, was similar across groups. Low doses of dietary tannins improved growth and dressing percentages when combined with a low-tannin diet but reduced growth rates when basal diets were tannin-rich. These findings suggest that dietary tannins' effects depend on the basal diet's composition.