Abstract: 【Objective】The objective of this experiment is to explore developmental changes of meat quality and antioxidant capacity of grazing and house-feeding goats. 【Method】Thirty-six kid goats were collected from 25 Xiangdong black female goats with estrus synchronization. All postnatal goats were fed on goat milk in 20 days. At 0, 7, and 14 d, 4 kid goats were slaughtered, respectively. And then the rest of these kids were assigned into two groups of 12 per group based on different feeding systems-grazing and house-feeding. At 21 d, the grazing group started to feed goat milk and forage, and the house-feeding group was fed on goat milk and a diet of forage supplemented with concentrate starter. All kids were weaned at 40 days. At 42, 56, and 70 d, 4 kids were slaughtered, respectively, in each group. The longissimus dorsi muscle from all 36 kids were collected and crude protein, intramuscular fat, amino acids, fatty acids contents and antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase, reduced glutathione and total antioxidant capacity ) activities were determined.【Result】The live weight and carcass weight of kids increased significantly with age (P＜0.05). When compared with house-feeding kids, grazing kids had lower (P＞0.05) live weight, but higher (P＞0.05) carcass weight. The content of crude protein in dry matter showed a linear increasing trend in two groups (P＜0.05), while intramuscular fat (IMF) showed an increasing trend (P＞0.05).Grazing kids presented lower contents of crude protein (P＞0.05) and higher IMF than house-feeding kids. The level of total amino acids (TAA), adult essential amino acids (AEAA) and baby amino acids (BEAA) were not affected significantly by age, whereas both TAA (P＞0.05) and flavor amino acids (FAA) (P＜0.05) showed an increasing trend. Likewise, TAA, AEAA and BEAA were not affected remarkably by feeding system; grazing kids had lower TAA, AEAA and FAA, but higher BEAA than house-feeding kids (P＞0.05). (4) Age did not affect saturated fatty acids (SFA) in grazing kid, but had a quadratic effect on SFA in rearing kids; monounsaturated fatty acids (MUFA) gradually decreased (P＜0.05), while polyunsaturated fatty acids (PUFA) and essential fatty acids (EFA) remarkably increased (P＜0.05) with age. Compared to house-feeding group, the grazing group showed lower levels of SFA, PUFA and EFA (P＞0.05), but higher level of MUFA (P＜0.05). Age did not have an effect on the active levels of catalase (CAT) and superoxide dismutase (SOD), however, had a quadratic effect on glutathione peroxidase (GSH-Px) (P＜0.05), and an increasing effect on total antioxidant capacity (T-AOC) (P＜0.05); reduced glutathione (GSH) in grazing group showed a linear decreasing trend (P＜0.05), but no significant difference in house-feeding group (P＞0.05).【Conclusion】Whatever the feeding system, kid goats at different ages had an increasing live weight and carcass weight, and in longissimus dorsi muscle, crude protein gradually increased, intramuscular fat showed an increasing trend, and amino acids and fatty acids contents fluctuated with age. Meanwhile, the grazing kids presented a relatively lower level of meat quality while higher antioxidant capacity than the house-feeding kids. Consequently, for producing the desirable chevon and achieving higher profit, an adaptive feeding system should be selected according to the natural environment, feedlot condition and the development profile of the muscle.

Key words: Xiangdong black goats, longissimus dorsi muscle, grazing, house-feeding, meat quality, antioxidant capacity