饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能、器官生长发育及肉品质的影响

引用本文

刘树林, 王雪, 李胤豪, 郭晓宇, 赵艳丽, 史彬林, 闫素梅. 饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能、器官生长发育及肉品质的影响[J]. 动物营养学报, 2021, 33(2): 877-887.

LIU Shulin, WANG Xue, LI Yinhao, GUO Xiaoyu, ZHAO Yanli, SHI Binlin, YAN Sumei. Effects of Dietary Linseed Oil and Linseed on Slaughter Performance, Organ Growth and Development and Meat Quality of Cashmere Goat Lambs[J]. Chinese Journal of Animal Nutrition, 2021, 33(2): 877-887.

饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能、器官生长发育及肉品质的影响

刘树林 , 王雪 , 李胤豪 , 郭晓宇 , 赵艳丽 , 史彬林 , 闫素梅

内蒙古农业大学动物科学学院, 内蒙古自治区高校动物营养与饲料科学重点实验室, 呼和浩特 010018

收稿日期: 2020-07-06

基金项目: 国家重点研发计划(2017YFD0500504)

作者简介: 刘树林(1991-), 女, 内蒙古呼和浩特人, 博士研究生, 动物营养与饲料科学专业。E-mail:1160628962@qq.com.

通信作者: 闫素梅, 教授, 博士生导师, E-mail:yansmimau@163.com.

摘要: 本试验旨在研究舍饲条件下饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能、器官生长发育及肉品质的影响。试验采用单因素完全随机试验设计，选择体重为(18.60±0.10) kg的60只4月龄阿尔巴斯断奶羯羔，随机分为对照组(CON组)、亚麻油组(LSO组)和亚麻籽组(HLS组)3个组，每组4个重复，每个重复5只羊。在育肥前期(1~30 d)、中期(31~60 d)和后期(61~90 d)，CON组饲喂基础饲粮，LSO组分别饲喂添加2.0%、2.0%和2.5%亚麻油的试验饲粮，HLS组分别饲喂添加5.5%、5.5%和7.0%热处理亚麻籽(120℃翻炒10 min)的试验饲粮。预试期14 d，正试期90 d。结果表明：1) LSO组羔羊的胴体重、屠宰率、肾脂重、尾脂重和脂肪组织重显著高于HLS组(P < 0.05)。2)与CON组相比，LSO组羔羊的蹄、毛皮和头+蹄+毛皮+血液重显著增加(P < 0.05)，而HLS组显著降低(P < 0.05)。与CON组和HLS组相比，LSO组羔羊的心脏、肾脏和内脏器官重显著增加(P < 0.05)，肺脏和胰脏指数显著降低(P < 0.05)。与CON组相比，LSO组和HLS组羔羊的网胃重显著降低(P < 0.05)，HLS组羔羊的瓣胃重显著降低(P < 0.05)。3) HLS组羔羊背最长肌的蒸煮损失和红度值显著高于LSO组(P < 0.05)，亮度值显著低于LSO组(P < 0.05)。与CON组相比，LSO组羔羊背最长肌的黄度值显著增加(P < 0.05)，而HLS组显著降低(P < 0.05)。与CON组相比，LSO组和HLS组羔羊的臂三头肌干物质、背最长肌粗蛋白质含量显著增加(P < 0.05)。由此可见，饲粮添加亚麻油降低了绒山羊羔羊外部组织器官、内脏器官和消化道占体重的比例，屠宰性能较好，脂肪沉积也有所增加；饲粮添加亚麻籽的羔羊肉色和肌肉营养价值优于饲粮添加亚麻油的羔羊。

关键词: 亚麻油亚麻籽绒山羊羔羊屠宰性能器官指数肉品质

Effects of Dietary Linseed Oil and Linseed on Slaughter Performance, Organ Growth and Development and Meat Quality of Cashmere Goat Lambs

LIU Shulin , WANG Xue , LI Yinhao , GUO Xiaoyu , ZHAO Yanli , SHI Binlin , YAN Sumei

Key Laboratory of Animal Nutrition and Feed Science in Inner Mongolia Autonomous Region, College of Animal Science, Inner Mongolia Agricultural University, Hohhot 010018, China

Corresponding author: YAN Sumei, professor, E-mail: yansmimau@163.com.

Abstract: This experiment was conducted to investigate the effects of dietary linseed oil and linseed on slaughter performance, organ growth and development and meat quality of cashmere goat lambs under stall-feeding condition. The experiment adopted a single-factor randomized block design, sixty 4-month-old Albas weaning lambs with body weight of (18.60±0.10) kg were randomly divided into 3 groups [control group (CON group), linseed oil group (LSO group) and linseed group (HLS group)] with 4 replicates per group and 5 lambs per replicate. During early fattening stage (1 to 30 d), middle fattening stage (31 to 60 d) and late fattening stage (61 to 90 d), lambs in the CON group were fed basal diets (concentrate-to-forage ratio was 5:5), lambs in the LSO group were fed basal diets supplemented with 2.0%, 2.0% and 2.5% linseed oil, and lambs in the HLS group were fed basal diets supplemented with 5.5%, 5.5% and 7.0% heated linseed (stir-fried at 120 ℃ for 10 min). The pre-experimental period lasted for 14 days, and the experimental period lasted for 90 days. The results showed as follows: 1) the carcass weight, dressing percentage, kidney fat weight, tail fat weight and fat tissue weight of lambs of LSO group were significantly higher than those of HLS group (P < 0.05). 2) Compared with the CON group, the weights of feet+wool and skin and head+feet+wool and skin+blood of lambs of LSO group were significantly increased (P < 0.05), while the HLS group was significantly decreased (P < 0.05). Compared with the CON group and HLS group, the weights of heart, kidney and internal organ of lambs of LSO group were significantly increased (P < 0.05), while the indexes of lung and pancreas were significantly decreased (P < 0.05). Compared with the CON group, the reticulum weight of lambs of LSO group and HLS group was significantly increased (P < 0.05), and the omasum weight of lambs of HLS group was significantly increased (P < 0.05). 3) The cooking loss and redness value of longissmus dorsi of lambs of HLS group were significantly higher than those of LSO group (P < 0.05), and the brightness value was significantly lower than that of LSO group (P < 0.05). Compared with the CON group, the contents of dry matter in triceps brachii and crude protein in longissmus dorsi of lambs of LSO group and HLS group were significantly increased (P < 0.05). In conclusion, dietary linseed oil increases the percentage to body weight of external tissue organs, internal organs and digestive tract of cashmere goat lambs, the slaughter performance is better, and the fat deposition is increased; the meat color and muscle nutritional value of lambs fed linseed diet are better than lambs fed linseed oi diet.

Key words: linseed oil linseed cashmere goat lambs slaughter performance organ index meat quality

阿尔巴斯白绒山羊是世界著名的绒肉兼用型品种，一直以自然放牧为主，其所产山羊绒以细、长、柔、软闻名世界，是养殖户的主要经济来源。然而，随着近年来羊绒价格的急剧下跌，羊肉需求量的不断增加，同时伴随着草原生态环境的恶化、草场载畜量的限制等因素，使得绒山羊由绒用向肉用、由放牧向舍饲转变，舍饲育肥成为了新的经济增长点。天然放牧的绒山羊肉味道鲜美、无膻味，富含蛋白质和n-3多不饱和脂肪酸(PUFA)，但研究也发现绒山羊由天然放牧转变成舍饲育肥后，其肉中饱和脂肪酸(SFA)含量显著增加，而有利于人体健康的n-3PUFA含量显著降低^[1]。因此，通过饲粮营养干预调控舍饲羊肉的脂肪酸组成是畜牧研究工作者的焦点之一。研究表明，摄入富含n-3PUFA的饲粮可改善反刍动物机体脂肪酸的组成，降低人类患心脑血管疾病的风险^[2]。亚麻油富含n-3PUFA，研究表明饲粮中添加亚麻油不仅可以促进羔羊的生长速度和饲料转化效率^[3]，还可以增加山羊肉中n-3PUFA含量^[4]。亚麻籽不仅富含n-3PUFA，且具有良好的过瘤胃效果。Nudda等^[5]研究指出，母羊补饲亚麻籽后可显著增加母羊肌内脂肪n-3PUFA含量，但减慢了其子代的生长并降低了胴体重。然而，目前的研究主要集中于饲粮添加亚麻油或亚麻籽对羊生长、育肥性能和机体组织脂肪酸组成的影响，鲜见饲粮添加亚麻油或亚麻籽对绒山羊羔羊生长和屠宰性能系统的比较研究。本课题组前期的研究结果显示，饲喂添加亚麻油饲粮的绒山羊羔羊的生长性能要优于饲喂添加亚麻籽饲粮，亚麻籽对绒山羊羔羊肌肉中n-3PUFA含量的促进作用及n-6PUFA/n-3PUFA的降低作用优于亚麻油^[6]。然而，饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能、器官生长发育及肉品质究竟产生什么样的影响，尚不清楚。因此，本试验主要研究了舍饲条件下饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能、器官生长发育和肉品质的影响，为合理制定绒山羊羔羊舍饲育肥方案、提高其肉品质提供数据支持。

1 材料与方法 1.1 试验动物与试验设计

从内蒙古白绒山羊种羊场选择体重为(18.60±0.10) kg的60只4月龄断奶羯羔，采用单因素完全随机试验设计，随机分为对照组(CON组)、亚麻油组(LSO组)和亚麻籽组(HLS组)3个组，每组4个重复，每个重复5只羊。试验分育肥前期(1~30 d)、中期(31~60 d)和后期(61~90 d)。在育肥前期、中期和后期，CON组饲喂基础饲粮，LSO组分别饲喂添加2.0%、2.0%和2.5%亚麻油的试验饲粮，HLS组分别饲喂添加5.5%、5.5%和7.0%亚麻籽的试验饲粮。各组饲粮的精粗比均为5 : 5。亚麻籽经过热处理(120 ℃翻炒10 min)，含油量为36%。HLS组中亚麻油含量与LSO组相似。试验期进行舍饲育肥，每天饲喂2次，自由采食、饮水。预试期14 d，正试期90 d。试验饲粮参照《肉羊饲养标准》(NY/T 816—2004)^[7]配制，其组成及营养水平见表 1。

表 1 试验饲粮组成及营养水平(风干基础) Table 1 Composition and nutrient levels of experimental diets (air-dry basis)

g/kg
项目 Items	育肥前期 Early fattening stage			育肥中期 Middle fattening stage			育肥后期 Late fattening stage
项目 Items	对照组 CON group	亚麻油组 LSO group	亚麻籽组 HLS group	对照组 CON group	亚麻油组 LSO group	亚麻籽组 HLS group	对照组 CON group	亚麻油组 LSO group	亚麻籽组 HLS group
原料Ingredients
苜蓿草颗粒Alfalfa hay particles	250.00	250.00	250.00	150.00	150.00	150.00	125.00	125.00	125.00
玉米秸秆草颗粒Maize straw particles	50.00	50.00	50.00	200.00	200.00	200.00	250.00	250.00	250.00
燕麦草颗粒Oat grass particles	200.00	200.00	200.00	150.00	150.00	150.00	125.00	125.00	125.00
玉米Corn	284.10	233.70	231.70	308.00	304.00	299.00	313.00	299.00	294.00
大豆粕Soybean meal	117.00	105.00	115.00	95.00	114.00	119.00	80.00	104.00	109.00
玉米干酒糟及其可溶物Corn DDGS	30.00	72.40	77.40	40.00	5.00	5.00	40.00	5.00	5.00
亚麻饼Linseed cake	48.00	48.00		35.00	35.00		45.00	45.00
亚麻籽Linseed			55.00			55.00			70.00
亚麻油Linseed oil		20.00			20.00			25.00
预混料Premix¹⁾	5.00	5.00	5.00	5.00	5.00	5.00	5.00	5.00	5.00
碳酸钙CaCO₃	2.00	2.00	2.00	2.00	2.00	2.00	2.00	2.00	2.00
磷酸氢钙CaHPO₄	2.00	2.00	2.00	2.00	2.00	2.00	2.00	2.00	2.00
氧化钠Na₂O	5.40	5.40	5.40	5.00	5.00	5.00	5.00	5.00	5.00
碳酸氢钠NaHCO₃	3.50	3.50	3.50	8.00	8.00	8.00	8.00	8.00	8.00
氧化镁MgO	3.00	3.00	3.00
合计Total	1 000.00	1 000.00	1 000.00	1 000.00	1 000.00	1 000.00	1 000.00	1 000.00	1 000.00
营养水平Nutrient levels²⁾
消化能DE/(MJ/kg)	112.90	115.70	115.20	114.70	116.20	115.80	111.00	113.90	113.60
粗蛋白质CP	166.10	166.20	166.10	145.20	141.80	142.60	133.70	131.70	132.20
粗脂肪EE	25.60	47.70	47.60	25.80	41.00	41.20	23.40	42.60	43.40
中性洗涤纤维NDF	374.40	381.00	389.70	399.90	381.90	392.20	398.40	379.50	392.20
酸性洗涤纤维ADF	204.40	210.00	214.70	216.20	210.20	221.90	215.70	209.10	223.60
钙Ca	9.90	9.80	9.70	9.30	9.70	9.60	8.90	9.30	9.20
磷P	4.10	4.10	4.20	4.00	4.00	4.10	3.80	3.70	3.80
1)预混料为每千克饲粮提供The premix provided the following per kg of diets：Fe 8 g，Cu 1.6 g，Zn 10 g，Mn 6 g，I 60 mg，Se 60 mg，Co 50 mg，VA 1 200 000 IU，VD₃ 500 000 IU，VE 2 500 IU，VK₃ 360 mg，VB₁ 70 mg，VB₂ 1 700 mg，VB₆ 180 mg，烟酸nicotinic acid 4 400 mg，D-泛酸D-pantothenic acid 3 400 mg，VB₁₂ 6 mg，生物素biotin 28 mg，叶酸folic acid 300 mg。 2)消化能为计算值，其余为实测值。DE was a calculated value, while the others were measured values.

表 1 试验饲粮组成及营养水平(风干基础) Table 1 Composition and nutrient levels of experimental diets (air-dry basis)

1.2 测定指标及方法 1.2.1 屠宰性能与脂肪沉积

试验结束时，分别从每个重复中随机挑选2只羔羊，每组共8只(禁食12 h、禁水2 h)进行屠宰，测定宰前活重(live weight before slaughter，LWBS)、胴体重、屠宰率、眼肌面积和背膘厚度(GR值)。胴体重是屠宰放血后，去除毛皮、头、内脏及前肢膝关节和后肢趾关节以下的部分后，整个躯体静置30 min后的重量；眼肌面积是测量左侧胴体倒数第1与第2肋骨之间背最长肌的横切面积；GR值是用游标卡尺测量左侧胴体倒数第1与第2肋骨之间，距离背脊中线11 cm处的组织厚度。屠宰率和眼肌面积计算公式如下：

屠宰后剥离大网膜脂、肠系膜脂、肾脂和尾脂并称重，计算各脂肪组织重占LWBS的比例，测定方法参照赵有璋^[8]。

1.2.2 组织器官指数和消化道指数

试验羊屠宰后，分离头、蹄、毛皮、接血并称重，计算其占LWBS的比例；分离心脏、肝脏、脾脏、肺脏、肾脏、胰腺，计算各器官重占LWBS的比例(器官指数)；分离瘤胃、网胃、瓣胃、皱胃、小肠及大肠，弃掉内容物并称重，计算各消化道重占LWBS的比例(消化道指数)。

1.2.3 肉品质

屠宰后，立即采集左侧背最长肌测定pH_{45 min}、pH_{2 h}、大理石纹、蒸煮损失、滴水损失、失水率和肉色。pH参照GB 5009.237—2016^[9]进行测定，蒸煮损失、滴水损失、失水率、肉色和大理石纹评分参照NY/T 1180—2006^[10]和NY/T 1333—2007^[11]进行测定。

采集右侧背最长肌、股二头肌、臂三头肌和臀肌样品，测定肌肉中干物质(DM)、粗蛋白质(CP)和粗脂肪(EE)含量，肌肉中水分含量参照GB/T 5009.3—2010^[12]进行测定，CP含量参照GB 5009.5—2010^[13]进行测定，EE含量参照GB/T 9695.7—2008^[14]进行测定。

1.3 数据处理

试验数据采用SAS 9.0软件的统计程序进行单因素方差分析，差异显著者采用Duncan氏法进行多重比较。P < 0.05表示差异显著，0.05≤P < 0.10表示差异趋于显著，P>0.10表示无显著差异。

2 结果 2.1 饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能和脂肪沉积的影响

由表 2可以看出，LSO组羔羊的胴体重、屠宰率、肾脂重、尾脂重和脂肪组织重显著高于HLS组(P < 0.05)，且胴体重和屠宰率分别提高了14.99%、9.02%，而CON组与LSO组和HLS组无显著差异(P>0.05)。LSO组羔羊的大网膜脂重、大网膜脂占LWBS的比例和脂肪组织占LWBS的比例显著高于CON组和HLS组(P < 0.05)，而HLS组与CON组之间无显著差异(P>0.05)。各组之间羔羊的眼肌面积、GR值、肠系膜脂重及肾脂、肠系膜脂与尾脂占LWBS的比例均无显著差异(P>0.05)。

表 2 饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能和脂肪沉积的影响 Table 2 Effects of linseed oil and linseed on slaughter performance and fat deposition of cashmere goat lambs

项目 Items	组别Groups			均值标准误 SEM	P值 P-value
项目 Items	CON	LSO	HLS	均值标准误 SEM	P值 P-value
胴体重Carcass weight/kg	11.95^ab	13.61^a	11.57^b	0.570	0.045
屠宰率Dressing percentage/%	44.82^ab	48.55^a	44.17^b	1.040	0.046
眼肌面积Loin eye area/cm²	8.39	8.86	8.33	0.440	0.674
GR值GR value/mm	10.38	11.84	10.39	0.760	0.319
重量Weight/g
肾脂Kidney fat	129.93^ab	153.91^a	120.63^b	8.501	0.032
大网膜脂Omental fat	729.31^b	1 053.55^a	696.62^b	12.409	< 0.001
肠系膜脂Mesenteric fat	487.49	547.97	417.84	47.495	0.178
尾脂Tail fat	12.39^ab	14.70^a	11.16^b	0.928	0.041
脂肪组织Fat tissue	1 473.59^ab	1 843.90^a	1 249.60^b	101.130	0.030
占宰前活重的比例Percentage of LWBS/%
肾脂Kidney fat	0.50	0.54	0.47	0.039	0.477
大网膜脂Omental fat	2.77^b	4.10^a	2.83^b	0.098	< 0.001
肠系膜脂Mesenteric fat	1.88	1.94	1.79	0.137	0.753
尾脂Tail fat	0.05	0.05	0.04	0.004	0.801
脂肪组织Fat tissue	5.19^b	6.45^a	5.07^b	0.146	< 0.001
同行数据肩标不同小写字母表示差异显著(P < 0.05)，相同或无字母表示差异不显著(P>0.05)。下表同。 In the same row, values with different small letter superscripts mean significant difference (P < 0.05), while with the same or no letter superscripts mean no significant difference (P>0.05). The same as below.

2.2 饲粮添加亚麻油和亚麻籽对绒山羊器官生长发育的影响

由表 3可以看出，与CON组相比，LSO组羔羊的蹄、毛皮和头+蹄+毛皮+血液重显著增加(P < 0.05)，而HLS组显著降低(P < 0.05)。与CON组和LSO组相比，HLS组羔羊的头和血液重显著降低(P < 0.05)，而毛皮和头+蹄+毛皮+血液占LWBS的比例显著增加(P < 0.05)，且LSO组与CON组之间无显著差异(P>0.05)。

表 3 饲粮添加亚麻油和亚麻籽对绒山羊羔羊头、蹄、毛皮和血液重及占宰前活重的比例的影响 Table 3 Effects of linseed oil and linseed on weight of head, feet, wool and skin and blood and percentage of LWBS of cashmere goat lambs

由表 4可以看出，与CON组和HLS组相比，LSO组羔羊的心脏、肾脏和内脏器官重显著增加(P < 0.05)，肺脏和胰脏指数显著降低(P < 0.05)，而HLS组与CON组之间无显著差异(P>0.05)。与CON组和LSO组相比，HLS组羔羊的肝脏、肾脏和内脏器官指数显著增加(P < 0.05)，而LSO组与CON组之间无显著差异(P>0.05)。

表 4 饲粮添加亚麻油和亚麻籽对绒山羊羔羊内脏器官重量和指数的影响 Table 4 Effects of linseed oil and linseed on weight and indexes of internal organs of cashmere goat lambs

项目 Items	组别Groups			均值标准误 SEM	P值 P-value
项目 Items	CON	LSO	HLS	均值标准误 SEM	P值 P-value
器官重量Organ weight/g
心脏Heart	108.30^b	117.73^a	103.57^b	1.641	< 0.001
肝脏Liver	615.42	634.87	604.53	17.300	0.468
脾脏Spleen	35.72	37.08	34.30	1.853	0.578
肺脏Lung	193.42	194.70	190.23	3.653	0.677
肾脏Kidney	91.77^b	97.28^a	90.92^b	1.783	0.041
胰脏Pancreas	36.53^a	37.20^a	29.34^b	1.836	0.011
内脏器官Internal organ	1 061.31^b	1 121.96^a	1 029.24^b	18.714	0.007
器官指数Organ index/%
心脏Heart	0.42	0.43	0.42	0.014	0.681
肝脏Liver	2.24^b	2.24^b	2.51^a	0.051	0.001
脾脏Spleen	0.13	0.13	0.15	0.008	0.180
肺脏Lung	0.76^a	0.70^b	0.77^a	0.017	0.021
肾脏Kidney	0.35^b	0.34^b	0.38^a	0.010	0.015
胰脏Pancreas	0.14^a	0.11^b	0.14^a	0.005	0.001
内脏器官Internal organ	4.00^b	3.96^b	4.38^a	0.063	< 0.001

由表 5可以看出，与CON组相比，LSO组和HLS组羔羊的网胃重显著降低(P < 0.05)，而LSO组与HLS组之间无显著差异(P>0.05)。与CON组相比，HLS组羔羊的瓣胃重显著降低(P < 0.05)，而LSO组与CON组和HLS组无显著差异(P>0.05)。LSO组羔羊的复胃重有高于HLS组的趋势(P=0.082)。HLS组羔羊的皱胃指数有高于CON组和LSO组的趋势(P=0.058)。与CON组和HLS组相比，LSO组羔羊的小肠、肠道和胃肠道指数显著降低(P < 0.05)，而HLS组与CON组之间无显著差异(P>0.05)。

表 5 饲粮添加亚麻油和亚麻籽对绒山羊羔羊消化道发育的影响 Table 5 Effects of linseed oil and linseed on digestive tract development of cashmere goat lambs

项目 Items	组别Groups			均值标准误 SEM	P值 P-value
项目 Items	CON	LSO	HLS	均值标准误 SEM	P值 P-value
消化道重量Digestive tract weight/kg
瘤胃Rumen	0.54	0.55	0.52	0.012	0.135
网胃Reticulum	0.10^a	0.08^b	0.08^b	0.002	0.001
瓣胃Omasum	0.11^a	0.10^ab	0.09^b	0.006	0.040
皱胃Abomasum	0.12	0.13	0.13	0.003	0.106
复胃Complex stomach	0.91	0.92	0.83	0.029	0.082
小肠Small intestine	0.74	0.72	0.71	0.023	0.650
大肠Large intestine	0.26	0.26	0.25	0.008	0.831
肠道Intestine tract	1.03	0.98	0.97	0.031	0.363
消化道Digestive tract	1.86	1.85	1.80	0.043	0.624
消化道指数Digestive tract index/%
瘤胃Rumen	2.06	2.05	2.05	0.067	0.993
网胃Reticulum	0.32	0.30	0.31	0.018	0.682
瓣胃Omasum	0.43	0.35	0.41	0.028	0.101
皱胃Abomasum	0.47	0.47	0.53	0.018	0.058
复胃Complex stomach	4.96	4.84	4.90	0.081	0.605
小肠Small intestine	2.90^a	2.33^b	2.97^a	0.085	< 0.001
大肠Large intestine	0.90	1.01	1.03	0.043	0.100
肠道Intestine tract	3.94^a	3.18^b	3.90^a	0.133	0.001
消化道Digestive tract	8.94^a	8.27^b	8.85^a	0.180	0.031

表 5 饲粮添加亚麻油和亚麻籽对绒山羊羔羊消化道发育的影响 Table 5 Effects of linseed oil and linseed on digestive tract development of cashmere goat lambs

2.3 饲粮添加亚麻油和亚麻籽对绒山羊羔羊肉品质的影响

由表 6可以看出，HLS组羔羊背最长肌的蒸煮损失和红度值显著高于LSO组(P < 0.05)，亮度值显著低于LSO组(P < 0.05)，而LSO组和HLS组与CON组无显著差异(P>0.05)。与CON组相比，LSO组羔羊背最长肌的黄度值显著增加(P < 0.05)，而HLS组显著降低(P < 0.05)。

表 6 饲粮添加亚麻油和亚麻籽对绒山羊羔羊背最长肌肉品质的影响 Table 6 Effects of linseed oil and linseed on meat quality of longissmus dorsi of cashmere goat lambs

由表 7可以看出，与CON组相比，LSO组和HLS组羔羊的臂三头肌DM、背最长肌CP含量显著增加(P < 0.05)，而LSO组与HLS组之间无显著差异(P>0.05)。LSO组羔羊的臂三头肌EE含量显著高于HLS组(P < 0.05)，而LSO组和HLS组与CON组无显著差异(P>0.05)。LSO组羔羊的股二头肌EE含量有高于HLS组的趋势(P=0.088)。

表 7 饲粮添加亚麻油和亚麻籽对绒山羊羔羊肌肉常规营养成分含量的影响(风干基础) Table 7 Effects of linseed oil and linseed on muscle routine nutrient contents of cashmere goat lambs (air-dry basis)

%
项目 Items	组别Groups			均值标准误 SEM	P值 P-value
项目 Items	CON	LSO	HLS	均值标准误 SEM	P值 P-value
干物质DM
背最长肌Longissmus dorsi	24.60	24.36	23.56	0.375	0.150
股二头肌Biceps femoris	24.37	24.40	24.48	0.359	0.971
臂三头肌Triceps brachii	23.59^b	24.49^a	24.60^a	0.234	0.011
臀肌Gluteus	25.00	25.13	24.83	0.288	0.759
粗蛋白质CP
背最长肌Longissmus dorsi	72.95^b	76.97^a	77.64^a	0.797	0.001
股二头肌Biceps femoris	76.05	76.73	77.13	0.666	0.523
臂三头肌Triceps brachii	75.88	75.74	76.46	0.402	0.420
臀肌Gluteus	75.57	75.63	75.52	0.377	0.979
粗脂肪EE
背最长肌Longissmus dorsi	12.50	13.34	12.61	0.800	0.728
股二头肌Biceps femoris	10.82	11.29	9.85	0.445	0.088
臂三头肌Triceps brachii	12.58^ab	13.65^a	11.04^b	0.572	0.014
臀肌Gluteus	12.06	11.80	11.04	0.493	0.335

3 讨论 3.1 饲粮添加亚麻油和亚麻籽对绒山羊羔羊屠宰性能、脂肪沉积和器官生长发育的影响

胴体重和屠宰率直接反映动物的产肉性能^[15]。本试验结果显示，LSO组羔羊的屠宰率、胴体重和脂肪沉积高于HLS组，饲粮添加亚麻油增加了产肉性能，与课题组前期关于生长育肥性能的研究结果^[16]相似。Brandt等^[17]研究显示，饲粮中添加油脂会增加脂肪组织重量，这与本试验研究结果相似。非胴体组成部分的质量和指数是衡量动物发育优劣的重要指标，在一定范围内增加表示器官机能增强^[18]。心脏、肝脏、脾脏、肺脏和肾脏作为主导机体新陈代谢的器官，必须发育到与机体相适应的比例才能承载机体生长所产生的负荷^[19]。反刍动物消化系统发育的健全程度可影响其对营养物质的消化能力，幼龄时复胃发育的程度直接影响成年后的消化能力^[20]。肠道是羔羊营养物质吸收和利用的主要器官，其重量的改变会影响营养物质的消化吸收，进而影响动物的生长性能^[21]。头、蹄、毛皮、血、内脏器官和消化道是动物的非胴体组成部分。本研究结果显示，与饲粮添加亚麻籽相比，添加亚麻油可以增加羔羊的头、蹄、毛皮和血液重，增加内脏器官的重量，即饲喂添加亚麻油较饲喂添加亚麻籽的羔羊增加了外部组织器官和内脏器官的重量，增强了机体代谢，促进了机体营养物质的吸收，进而增加了绒山羊羔羊的胴体重和脂肪沉积，但上述非胴体组成部分头、蹄、毛皮和血液重占体重的比例、内脏器官指数、肠道与消化道指数均降低，因此屠宰率增加。其原因可能是饲喂添加亚麻籽饲粮的羔羊机体各组织器官尚未发育完善，导致吸收的营养物质一部分用于弥补组织脏器的发育，并未完全转化成肌肉与脂肪的形式沉积在体内^[22]。此外，可能是由于富含α-亚麻酸的亚麻油能显著抑制瘤胃甲烷产生菌，并抑制甲烷生成，改善瘤胃发酵环境，减少肉羊以甲烷形式损失的饲粮能量，提高饲粮DM表观消化率^[23]，促进消化道发育，进而提高了绒山羊羔羊的屠宰性能。课题组前期研究得出，亚麻籽组羔羊瘤胃中含有较多的n-3PUFA^[16]，多不饱和脂肪酸对瘤胃微生物有一定的毒害作用，抑制了瘤胃中的主要微生物，降低了微生物对中性洗涤纤维和酸性洗涤纤维的降解率^[24]，抑制了其对营养物质的消化、吸收和利用，从而降低了绒山羊羔羊的屠宰性能。本文尚未对各组羔羊的营养物质消化率进行研究，后续需对其进行分析，以进一步明确其影响原因。

3.2 饲粮添加亚麻油和亚麻籽对绒山羊羔羊肉品质的影响

肉品感官指标(肉色、大理石纹评分、失水率等)和营养指标(CP、EE等)是肉品质评定的常用指标。蒸煮损失是测定肌肉在烹煮过程中保水情况的主要指标，蒸煮损失越低，肌肉在烹煮过程中的系水力就越高^[25]。本研究结果显示，饲喂添加亚麻籽的羔羊背最长肌的蒸煮损失高于饲喂添加亚麻油的羔羊，这说明饲粮中添加亚麻油可以提高羔羊肌肉的保水能力，这可能是由于饲粮中添加亚麻油促进了羔羊肌肉中的脂肪沉积，因而提高了肌肉的系水力。肉色是消费者最初观察、判断和选择肉类的一个主要感官指标^[26]，肉色的变化主要决定于肌肉中亚铁肌红蛋白(鲜红)、肌红蛋白(暗红色)和正铁肌红蛋白(灰色、褐色)的比例^[27]，一般认为鲜肉的颜色应该是鲜红色或者亮粉色。大理石花纹评分是衡量肌肉脂肪含量和多汁性的重要指标^[28]。脂肪细胞是白色的，肌内脂肪含量越高，肌肉就越亮，即亮度值越大^[29]。肉色越红则红度值越大，脂质氧化可改变血红素的化学性质而引起肌红蛋白氧化，导致肉色损失呈现棕色^[30]，红度值变小。肉色的黄度值可以反映肌肉中的脂质沉积^[31]。本研究结果显示，HLS组羔羊背最长肌的大理石纹是微量脂，红度值高于CON组和LSO组，而亮度和黄度值都低于CON组和LSO组，这说明HLS组羔羊肌肉的感官评分要优于CON组和LSO组。一方面可能是由于亚麻籽中含有生育酚、维生素E等抗氧化剂，抗氧化剂可以抑制羊肉中的肌红蛋白向正铁肌红转化，保护羊肉避免褪色^[32]；另一方面可能是由于CON组和LSO组羔羊肌肉中脂肪含量较高，脂肪中含有较多的黄色素，因此HLS组羔羊的肉色较好。肌肉CP和EE含量是反映其营养价值的主要指标，水分含量同肉的多汁性有着密切联系。本研究结果显示，LSO组和HLS组各肌肉组织中DM和CP含量均高于CON组，EE含量是LSO组>CON组>HLS组。这说明饲粮中添加亚麻油和亚麻籽可以提高绒山羊羔羊肌肉DM、CP含量，且HLS组羔羊肌肉组织中EE含量低于LSO组，即饲粮添加亚麻油和亚麻籽都可以改善羔羊肌肉的营养价值，但亚麻籽优于亚麻油。这可能是由于亚麻籽对羔羊肌肉组织中α-亚麻酸(α-linolenic acid，ALA)和二十二碳六烯酸(docosahexaenoic acid，DHA)含量的促进效果优于亚麻油^[6]。有研究表明，ALA能显著减少细胞内甘油三酯的合成，抑制3T3-L1前脂肪细胞分化^[33]，DHA可抑制3T3-L1脂肪细胞分化，促进脂肪细胞水解，并诱导细胞凋亡^[34]。因此，饲粮添加亚麻籽显著降低了肌肉组织中EE含量，从而增加了DM和CP含量。

4 结论

① 饲粮添加亚麻油降低了绒山羊羔羊外部组织器官、内脏器官和消化道占体重的比例，其屠宰性能优于饲粮添加亚麻籽，脂肪沉积也有所增加。

② 饲粮添加亚麻籽的羔羊肉色和肌肉营养价值优于饲粮添加亚麻油的羔羊。

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