Chen Yinyin, Gong Xiaoxiao, Yang Tianyu, Jiang Maocheng, Wang Lin, Zhan Kang, Lin Miao, Zhao Guoqi
College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou 225009, China.
Animals (Basel). 2021 Oct 25;11(11):3046. doi: 10.3390/ani11113046.
Sixty castrated male Haimen white growing goats with an initial age of 100 days old and similar body weight (16 ± 1.5 kg) were selected and randomly allocated into five groups with three replicates in each group with four goats in each pen (5 m × 3.2 m). Goats in the control group (CG) were fed a basal pelleted total mixed ration supplemented with 30% alfalfa hay pellet, while experimental treatments (G6, G12, G18, or G24) were supplemented with four levels (6%, 12%, 18%, or 24%) of GBLR replacing alfalfa hay pellet in the diet, separately. Results showed that (1) the final body weight, average daily gain, and average feed intake of G18 was significantly higher ( < 0.05) than CG; in contrast, the feed conversion ratio of G18 was significantly lower than CG and G12 ( < 0.05); the feed cost per head per day of CG was significantly higher ( < 0.05) than that of G18 and G24, and exhibited obvious linearly decrease ( = 0.04) with increasing GBLR supplementation; and apparent total-tract digestibility of DM and NDF in GBLR treatments were significantly higher ( < 0.05) than CG; (2) alanine transaminase (ALT) concentration in the G18 group was significantly lower ( < 0.05) than those in the control group; aspartate transaminase (AST) concentration in the G24 was significantly lower ( < 0.05) than those in the control group, and an increase in dietary level of GBLR tended to result in a linear decrease ( = 0.09) in the concentration of serum AST; (3) the concentration of malondialdehyde (MDA) demonstrated a tendency to decrease ( = 0.06) linearly with increasing GBLR supplementation; however, glutathione peroxidase (GSH-PX) activity in G12 was significantly higher ( < 0.05) than CG, G6, and G24; in addition, superoxide dismutase (SOD) activity in G18 was significantly higher ( < 0.05) than CG and G6; concentration of immunoglobulin M (IgM), immunoglobulin G (IgG), and immunoglobulin A (IgA) were not affected by GBLR, but increasing dietary GBLR showed a tendency ( = 0.08) to linearly increase the IgG concentration; the content of interleukin 4 (IL4) was significantly higher ( < 0.05) in G12, G18, and G24 than that in CG and G6; (4) There were similar NH-N, pH, TVFA, and butyrate for goats fed different levels of GBLR supplementation; the C2 ( = 0.07) and acetate: propionate ( = 0.06) demonstrated a tendency to increase linearly with increasing level of GBLR supplementation, separately; however, it was observed that concentration of propionate showed a tendency to decrease ( = 0.08) linearly in response to GBLR supplementation; and (5) Increasing dietary GBLR tended to linearly enhance the lightness (L*) ( = 0.07) and yellowness (b*) ( = 0.09) values of longissimus dorsi muscles; the redness (a*) value in G18 was significantly higher than that in CG ( < 0.05).
选取60只初始年龄为100日龄、体重相近（16±1.5千克）的去势雄性海门白山羊，随机分为5组，每组3个重复，每个栏舍4只羊（5米×3.2米）。对照组（CG）的山羊饲喂基础颗粒全混合日粮，并补充30%的苜蓿干草颗粒，而试验处理组（G6、G12、G18或G24）分别用4个水平（6%、12%、18%或24%）的γ-氨基丁酸（GBLR）替代日粮中的苜蓿干草颗粒。结果表明：（1）G18组的末体重、平均日增重和平均采食量显著高于对照组（P<0.05）；相反，G18组的饲料转化率显著低于对照组和G12组（P<0.05）；对照组每头羊每天的饲料成本显著高于G18组和G24组（P<0.05），且随着GBLR添加量的增加呈明显线性下降（P=0.04）；GBLR处理组的干物质（DM）和中性洗涤纤维（NDF）的表观全肠道消化率显著高于对照组（P<0.05）；（2）G18组的谷丙转氨酶（ALT）浓度显著低于对照组（P<0.05）；G24组的谷草转氨酶（AST）浓度显著低于对照组（P<0.05），且日粮中GBLR水平的增加倾向于使血清AST浓度呈线性下降（P=0.09）；（3）丙二醛（MDA）浓度随着GBLR添加量的增加呈线性下降趋势（P=0.06）；然而，G12组的谷胱甘肽过氧化物酶（GSH-PX）活性显著高于对照组、G6组和G24组（P<0.05）；此外，G18组的超氧化物歧化酶（SOD）活性显著高于对照组和G6组（P<0.05）；免疫球蛋白M（IgM）、免疫球蛋白G（IgG）和免疫球蛋白A（IgA）的浓度不受GBLR影响，但日粮中GBLR的增加倾向于使IgG浓度呈线性增加（P=0.08）；白细胞介素4（IL4）的含量在G12组、G18组和G24组显著高于对照组和G6组（P<0.05）；（4）不同GBLR添加水平的山羊瘤胃液中氨态氮（NH₃-N）、pH值、挥发性脂肪酸（TVFA）和丁酸含量相似；乙酸比例（C₂，P=0.07）和乙酸:丙酸比例（P=0.06）分别随着GBLR添加水平的增加呈线性增加趋势；然而，丙酸浓度随着GBLR添加量的增加呈线性下降趋势（P=0.08）；（5）日粮中GBLR的增加倾向于线性提高背最长肌的亮度（L*）值（P=0.07）和黄度（b*）值（P=0.09）；G18组的红度（a*）值显著高于对照组（P<0.05）。
