饲粮中添加膨化苜蓿草粉-亚麻籽对母猪初乳成分及母猪、仔猪血清脂质代谢指标和脂肪酸含量的影响

引用本文

苏莹莹, 潘培颖, 刘旭乐, 赵淑敏, 王成章, 焦喜兰, 李振田, 孙骁. 饲粮中添加膨化苜蓿草粉-亚麻籽对母猪初乳成分及母猪、仔猪血清脂质代谢指标和脂肪酸含量的影响[J]. 动物营养学报, 2022, 34(1): 190-204.

SU Yingying, PAN Peiying, LIU Xule, ZHAO Shumin, WANG Chengzhang, JIAO Xilan, LI Zhentian, SUN Xiao. Effects of Extruded Alfalfa Meal-Flaxseed Supplementation in Diets on Colostrum Composition of Sows and Serum Lipid Metabolism Indexes and Fatty Acid Contents of Sows and Piglets[J]. Chinese Journal of Animal Nutrition, 2022, 34(1): 190-204.

饲粮中添加膨化苜蓿草粉-亚麻籽对母猪初乳成分及母猪、仔猪血清脂质代谢指标和脂肪酸含量的影响

苏莹莹¹ , 潘培颖¹ , 刘旭乐¹ , 赵淑敏¹ , 王成章^1,2,3 , 焦喜兰⁴ , 李振田^1,2,3 , 孙骁¹

1. 河南农业大学动物科技学院, 郑州 450002;
2. 河南省草地资源创新与利用重点实验室, 郑州 450002;
3. 河南省牧草工程技术研究中心, 郑州 450002;
4. 河南农业大学动物医学院, 郑州 450002

收稿日期: 2021-06-10

基金项目: 郑州市农业科技重大专项"安全高效低成本饲料产业化共性技术研究与示范"(30800063)

作者简介: 苏莹莹(1995-), 女, 河南焦作人, 硕士研究生, 从事动物营养与饲料科学研究。E-mail: hnndsuying@163.com.

通信作者: 李振田, 副教授, 硕士生导师, E-mail: Lizhentian2006@126.com;
孙骁, E-mail: hnndsunxiao@126.com.

摘要: 本试验旨在研究饲粮中添加膨化苜蓿草粉-亚麻籽对母猪初乳成分及母猪、仔猪血清脂质代谢指标和脂肪酸含量的影响。试验选用80头胎次、体况和预产期接近的长×大妊娠母猪，随机分为4组，每组4个重复，每个重复5头，单栏饲喂。对照组、试验Ⅰ组、试验Ⅱ组和试验Ⅲ组分别饲喂添加不同比例（0、5%、10%和15%）膨化苜蓿草粉-亚麻籽的试验饲粮。试验从母猪妊娠第83天开始，至哺乳第21天结束。结果表明：1）与对照组相比，试验Ⅰ组的初乳中乳糖含量有升高的趋势（P=0.090），试验Ⅱ组和试验Ⅲ组的初乳中乳蛋白含量显著升高（P < 0.05），试验Ⅱ组的初乳中总固形物含量有升高的趋势（P=0.099）。2）与对照组相比，试验Ⅱ组的母猪血清中低密度脂蛋白胆固醇（LDL-C）含量有降低的趋势（P=0.089）。3）与对照组相比，试验Ⅱ组的仔猪血清中LDL-C含量显著降低（P < 0.05），血清中总胆固醇（TC）含量有降低的趋势（P=0.081）。4）与对照组相比，试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的母猪血清中亚油酸（LA）、n-6多不饱和脂肪酸（PUFA）含量和n-6多不饱和脂肪酸/n-3多不饱和脂肪酸（n-6 PUFA/n-3 PUFA）显著降低（P < 0.05），血清中二十碳五烯酸（EPA）和二十二碳五烯酸（DPA）含量显著升高（P < 0.05）；试验Ⅱ组和试验Ⅲ组的血清中花生四烯酸（AA）和饱和脂肪酸（SFA）含量显著降低（P < 0.05），血清中α-亚麻酸（ALA）、n-3多不饱和脂肪酸（n-3 PUFA）含量和不饱和脂肪酸/饱和脂肪酸（UFA/SFA）显著升高（P < 0.05）。5）与对照组相比，试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的仔猪血清中LA、AA、n-6 PUFA含量和n-6 PUFA/n-3 PUFA显著降低（P < 0.05），血清中EPA含量显著升高（P < 0.05）；试验Ⅱ组的血清中二十二碳六烯酸（DHA）、DPA、单不饱和脂肪酸（MUFA）、PUFA、n-3 PUFA含量和UFA/SFA显著升高（P < 0.05）；试验Ⅱ组和试验Ⅲ组的血清中ALA含量显著升高（P < 0.05），血清中SFA含量显著降低（P < 0.05）。6）相关性分析显示，母猪血清中高密度脂蛋白胆固醇（HDL-C）含量与仔猪血清中TC和甘油三酯（TG）含量呈显著负相关（P < 0.05），与仔猪血清中HDL-C含量呈显著正相关（P < 0.05）；母猪血清中LDL-C含量与仔猪血清中TC、TG和LDL-C含量呈显著正相关（P < 0.05）。母猪血清中EPA、DHA、DPA、ALA和n-3 PUFA含量与仔猪血清中EPA、DHA、DPA、ALA、UFA、n-3 PUFA含量和UFA/SFA呈显著正相关（P < 0.05），与仔猪血清中n-6 PUFA/n-3 PUFA呈显著负相关（P < 0.05）。综上所述，饲粮中添加膨化苜蓿草粉-亚麻籽可以提高母猪初乳品质，改善母猪血清脂质代谢，增加母猪血清中n-3 PUFA含量，从而对仔猪的血清脂质代谢和脂肪酸组成也产生积极影响，有利于仔猪的机体健康。

关键词: 膨化苜蓿草粉亚麻籽初乳成分血清脂质代谢脂肪酸含量

Effects of Extruded Alfalfa Meal-Flaxseed Supplementation in Diets on Colostrum Composition of Sows and Serum Lipid Metabolism Indexes and Fatty Acid Contents of Sows and Piglets

SU Yingying¹ , PAN Peiying¹ , LIU Xule¹ , ZHAO Shumin¹ , WANG Chengzhang^1,2,3 , JIAO Xilan⁴ , LI Zhentian^1,2,3 , SUN Xiao¹

1. College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China;
2. Key Laboratory of Innovation and Utilization of Grassland Resources in Henan Province, Zhengzhou 450002, China;
3. Henan Engineering Research Center for Forage, Zhengzhou 450002, China;
4. College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China

Corresponding author: LI Zhentian, associate professor, E-mail: Lizhentian2006@126.com;
SUN Xiao, E-mail: hnndsunxiao@126.com.

Abstract: This experiment was conducted to study the effects of extruded alfalfa meal-flaxseed supplementation in diets on colostrum composition of sows and serum lipid metabolism indexes and fatty acid contents of sows and piglets. Eighty Landrace×Large White pregnant sows with similar parity, body condition and expected delivery date were randomly divided into 4 groups with 4 replicates in each group and 5 sows in each replicate, and each of them was raised in a single column. Sows in the control group, experimental group Ⅰ, experimental group Ⅱ and experimental group Ⅲ were fed diets supplemented with different proportions (0, 5%, 10% and 15%) of extruded alfalfa meal-flaxseed, respectively. The experiment began from day 83 of pregnancy to day 21 of lactation in sows. The results showed as follows: 1) compared with the control group, the content of lactose in colostrum of experimental group Ⅰ had an increasing trend (P=0.090), the content of milk protein in colostrum of experimental group Ⅱ and experimental group Ⅲ was significantly increased (P < 0.05), and the content of total solid in colostrum of experimental group Ⅱ had an increasing trend (P=0.099). 2) Compared with the control group, the content of low density lipoprotein cholesterol (LDL-C) in serum of sows of experimental group Ⅱ had a decreasing trend (P=0.089). 3) Compared with the control group, the content of LDL-C in serum of piglets of experimental group Ⅱ was significantly decreased (P < 0.05), and the content of total cholesterol (TC) in serum had a decreasing trend (P=0.081). 4) Compared with the control group, the contents of linoleic acid (LA), n-6 polyunsaturated fatty acid (PUFA) and n-6 polyunsaturated fatty acid to n-3 polyunsaturated fatty acid (n-6 PUFA/n-3 PUFA) in serum of sows of experimental group Ⅰ, experimental group Ⅱ and experimental group Ⅲ were significantly decreased (P < 0.05), and the contents of eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) in serum were significantly increased (P < 0.05); the contents of arachidonic acid (AA) and saturated fatty acid (SFA) in serum of experimental group Ⅱ and experimental group Ⅲ were significantly decreased (P < 0.05), while the contents of α-linolenic acid (ALA), n-3 polyunsaturated fatty acid (n-3 PUFA) and unsaturated fatty acid to saturated fatty acid (UFA/SFA) were significantly increased (P < 0.05). 5) Compared with the control group, the contents of LA, AA, n-6 PUFA and n-6 PUFA/n-3 PUFA in serum of piglets of experimental group Ⅰ, experimental group Ⅱ and experimental group Ⅲ were significantly decreased (P < 0.05), while the content of EPA in serum was significantly increased (P < 0.05); the contents of DHA, DPA, monounsaturated fatty acid (MUFA), PUFA, n-3 PUFA and UFA/SFA in serum of experimental group Ⅱ were significantly increased (P < 0.05); the content of ALA in serum of experimental group Ⅱ and experimental group Ⅲ was significantly increased (P < 0.05), while the content of SFA in serum was significantly decreased (P < 0.05). 6) Correlation analysis showed that the content of high density lipoprotein cholesterol (HDL-C) in serum of sows was significantly negatively correlated with the contents of TC and TG in serum of piglets (P < 0.05), and was significantly positively correlated with the content of HDL-C in serum of piglets (P < 0.05); the content of LDL-C in serum of sows was significantly positively correlated with the contents of TC, TG and LDL-C in serum of piglets (P < 0.05). The contents of EPA, DHA, DPA, ALA and n-3 PUFA in serum of sows were significantly positively correlated with the contents of EPA, DHA, DPA, ALA, UFA, n-3 PUFA and UFA/SFA in serum of piglets (P < 0.05), and negatively correlated with the n-6 PUFA/n-3 PUFA in serum (P < 0.05). To sum up, the extruded alfalfa meal-flaxseed supplementation in diets can improve the colostrum quality, improve the serum lipid metabolism of sows, increase the content of n-3 PUFA in serum of sows, which has a positive effect on the serum lipid metabolism and fatty acid composition of piglets, and is beneficial to the health of piglets.

Key words: extruded alfalfa meal flaxseed colostrum composition serum lipid metabolism fatty acid contents

近年来，由于遗传选育、营养与饲养管理、疾病控制以及养殖设备等的巨大投入，国内养猪业得到了快速发展，母猪的年生产力有了较大提高，每头母猪年断奶仔猪数显著增加^[1]。与此同时，母猪的繁殖障碍问题也日益增多，其原因可能是经过遗传改良的高产母猪需要更精准的营养供给以满足妊娠和泌乳的需要，而通过营养调控手段来适应母猪的营养需要增加和体储减少对于改善母猪繁殖障碍和发挥母猪生产潜力具有重要意义^[2]。此外，母猪可以通过母乳来为仔猪提供营养物质和其他生物活性物质，而初乳中含有大量从母猪血液中移行来的养分，其成分的变化也会影响仔猪的血液指标^[3]。因此，通过调节母猪的营养水平和健康状况对于维持子代的生长发育和机体健康也可能是一种有效策略。

紫花苜蓿作为一种优质的饲料原料，其富含的多种生物活性物质在维持母猪繁殖性能、促进胎儿早期发育等方面具有重要作用^[4]，其中的黄酮类化合物具有类雌激素作用，可以通过调节生殖相关激素的分泌来改善母猪的泌乳能力^[1]；皂苷可以通过调节胆固醇代谢相关基因的表达来发挥降脂作用^[5-6]，还能够通过恢复谷胱甘肽的动态平衡和抑制细胞凋亡来缓解氧化应激^[7]；叶酸和β-胡萝卜素与促进胚胎发育、提高母猪泌乳量和改善乳品质等有密切关系^[8]。亚麻籽中含有丰富的α-亚麻酸(ALA)、木脂素、维生素以及黄酮类、植物甾醇类等功能性成分，具有促进视神经和大脑发育、调节动物机体脂质代谢和畜产品品质、改善母猪繁殖性能及后代仔猪生长性能等作用^[9-10]。然而，亚麻籽中含有的抗营养因子，如生氰糖苷、抗维生素B₆因子和植酸等，会导致动物中毒和生产性能降低^[11-13]。通过膨化加工可以有效降低抗营养因子活性，增加氨基酸和可溶性纤维含量，提高营养物质利用率，进而改善亚麻籽的饲用品质，拓宽亚麻籽及其加工副产品在畜禽生产中的应用，充分发挥其潜在价值^{[12, 14-15]}。目前，膨化饲粮在水产动物^[16]、宠物^[17]和仔猪^[18]中的应用较多，而在母猪中应用的相关研究较少，对母猪营养物质代谢和机体健康影响的研究也非常有限。因此，本试验旨在通过在饲粮中添加膨化苜蓿草粉-亚麻籽，研究其对母猪初乳成分的影响，并测定母猪及所产仔猪血清脂质代谢指标和血清脂肪酸含量来探讨其代谢调节机制，旨在为膨化苜蓿草粉-亚麻籽在母猪生产中“母子一体化”营养调控中的应用提供依据。

1 材料与方法 1.1 试验材料

苜蓿草粉是用同一批次初花期刈割所得的紫花苜蓿经自然干燥加工而成，与亚麻籽按照1 ∶ 1的比例进行膨化加工(粉碎粒度1 mm，调质温度60 ℃，蒸汽压力0.5 MPa，喂料区温度110 ℃，混合区温度130 ℃，泄压区温度140 ℃，喂料频率18 Hz，螺杆转速90 r/min)，苜蓿草粉-亚麻籽膨化前后营养水平变化见表 1。

表 1 苜蓿草粉-亚麻籽膨化前后营养水平变化(风干基础) Table 1 Changes of nutritional levels of alfalfa meal-flaxseed before and after extruding (air-dry basis)

1.2 试验动物和试验设计

采用单因素试验设计，选取80头胎次、体况和预产期接近的健康长白×大白妊娠母猪，随机分为4组，每组4个重复，每个重复5头，单栏饲喂。对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组分别饲喂添加不同比例(0、5%、10%和15%)膨化苜蓿草粉-亚麻籽的试验饲粮。试验期从母猪妊娠第83天开始，至哺乳第21天结束。各试验母猪妊娠后期采取限饲，哺乳期自由采食，均自由饮水。试验饲粮参照NRC(2012)的母猪营养需要，按等能等氮的原则配制，试验饲粮组成及营养水平见表 2，试验饲粮脂肪酸组成见表 3。

表 2 试验饲粮组成及营养水平(风干基础) Table 2 Composition and nutrient levels of experimental diets (air-dry basis)

%
项目 Items	对照组 Control group	试验Ⅰ组 Trial group Ⅰ	试验Ⅱ组 Trial group Ⅱ	试验Ⅲ组 Trial group Ⅲ
原料Ingredients
膨化苜蓿草粉-亚麻籽Extruded alfalfa meal-flaxseed		5.00	10.00	15.00
豆粕Soybean meal (CP 44.2%)	20.40	18.80	17.60	15.90
玉米Corn	57.80	55.40	54.50	51.60
麸皮Wheat bran	2.50	2.00
次粉Wheat middling	10.00	10.00	10.00	10.00
豆油Soybean oil	3.00	2.50	1.70	1.40
石粉Limestone	1.40	1.40	1.40	1.40
鱼粉Fish meal (CP 60.2%)	2.00	2.00	2.00	2.00
苏氨酸Thr (99%)	0.10	0.10	0.10	0.10
赖氨酸Lys (98%)	0.30	0.30	0.30	0.30
磷酸氢钙CaHPO₄	1.00	1.00	0.90	0.80
食盐NaCl	0.40	0.40	0.40	0.40
氯化胆碱Choline chloride	0.10	0.10	0.10	0.10
预混料Premix¹⁾	1.00	1.00	1.00	1.00
合计Total	100.00	100.00	100.00	100.00
营养水平Nutrient levels²⁾
粗纤维CF	2.01	2.14	2.34	2.48
粗脂肪EE	5.67	6.14	6.31	6.88
酸性洗涤纤维ADF	5.04	5.78	6.25	6.44
中性洗涤纤维NDF	9.67	11.53	12.89	13.11
粗蛋白质CP	17.50	17.50	17.50	17.50
粗灰分Ash	4.89	5.01	5.10	5.24
钙Ca	0.90	0.90	0.90	0.90
总磷TP	0.59	0.58	0.56	0.55
有效磷AP	0.45	0.45	0.45	0.45
赖氨酸Lys	1.19	1.20	1.20	1.20
亚油酸Linoleic acid	1.55	1.48	1.42	1.35
消化能DE/(MJ/kg)	14.22	14.22	14.22	14.22
1)预混料为每千克饲粮提供The premix provided the following per kg of diets: VA 5 500 IU，VD₃ 500 IU，VE 66.1 IU，VB₁₂ 28.2 μg，VB₂ 5.1 mg，VB₃ 12.6 mg，VB₅ 29.8 mg，VK₃ 540 mg，Mn (as manganese sulfate) 40 mg，Zn (as zinc sulfate) 120 mg，Fe (as ferrous sulfate) 150 mg，Cu (as copper sulfate) 10 mg，Co (as cobalt chloride) 1 mg，Se (as sodium selenite) 0.25 mg，I (as potassium iodide) 0.5 mg。 2)营养水平为计算值，依据《中国饲料成分及营养价值表(第28版)》。Nutrient levels were calculated values, which according to Tables of Feed Composition and Nutritive in China (the 28th ed).

表 2 试验饲粮组成及营养水平(风干基础) Table 2 Composition and nutrient levels of experimental diets (air-dry basis)

表 3 试验饲粮脂肪酸组成 Table 3 Fatty acid composition of experimental diets

项目 Items	对照组 Control group	试验Ⅰ组 Trial group Ⅰ	试验Ⅱ组 Trial group Ⅱ	试验Ⅲ组 Trial group Ⅲ
亚油酸LA (C24∶1)/(mg/kg)	1 093.41	1 173.56	883.31	796.93
花生四烯酸AA (C20∶4n-6)/(mg/kg)	7.08	7.73	30.31	32.63
二十碳五烯酸EPA (C20∶5n-3)/(mg/kg)	28.33	35.30	41.80	41.50
二十二碳六烯酸DHA (C22∶6n-3)/(mg/kg)	2.95	2.17	3.52	4.21
α-亚麻酸ALA (C18∶3n)/(mg/kg)	329.49	551.41	553.59	640.29
饱和脂肪酸SFA/(mg/kg)	1 331.31	1 169.10	975.45	927.71
不饱和脂肪酸UFA/(mg/kg)	3 047.52	3 264.30	3 421.13	3 463.42
不饱和脂肪酸/饱和脂肪酸UFA/SFA	2.29	2.79	3.51	3.73
单不饱和脂肪酸MUFA/(mg/kg)	814.47	857.74	762.04	758.59
多不饱和脂肪酸PUFA/(mg/kg)	1 665.31	1 675.26	1 758.46	1 875.27
n-6多不饱和脂肪酸n-6 PUFA/(mg/kg)	1 629.78	1 181.29	913.62	829.56
n-3多不饱和脂肪酸n-3 PUFA/(mg/kg)	35.53	43.97	44.84	45.71
n-6多不饱和脂肪酸/n-3多不饱和脂肪酸 n-6 PUFA/n-3 PUFA	45.87	26.87	20.38	18.15

表 3 试验饲粮脂肪酸组成 Table 3 Fatty acid composition of experimental diets

1.3 样品采集

母猪开始分娩4 h内，每个重复随机选取1头母猪，分别从前、中、后3个部位的乳头采集混合乳汁20 mL，置于-20 ℃冰箱中保存。在哺乳期第20天，每个重复随机选取1头母猪，空腹状态下前腔静脉采血10 mL于促凝管内，室温静置1 h后，4 ℃、3 000 r/min离心10 min，分离血清，置于-20 ℃冰箱中保存。仔猪出生后，于其哺乳第20天，每个重复随机选取1窝仔猪，每窝选取1头与窝平均体重相近的仔猪，空腹状态下前腔静脉采血5 mL于促凝管内，室温静置1 h后，4 ℃、3 000 r/min离心10 min，分离血清，置于-20 ℃冰箱中保存。

1.4 乳成分的测定

采用乳品成分快速分析仪(Miko-Scan FT120，丹麦Foss公司)测定乳样中乳脂、乳糖、乳蛋白和总固形物含量，每个样品测定3次，取平均值。

1.5 血清脂质代谢指标的测定

采用全自动生化分析仪(Hitachi-7020，Hitachi，日本)测定血清中葡萄糖(GLU)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)含量，试剂盒均购自南京建成生物工程研究所，测定方法严格按照试剂盒说明书进行。

1.6 饲粮和血清脂肪酸含量的测定

参照刘晓杰等^[19]的方法进行甲酯化处理，采用安捷伦7890A型气相色谱仪测定饲粮和血清中各脂肪酸含量。色谱柱为DB-225MS毛细管柱(0.25 mm×60 m，0.25 μm)，升温条件：初始柱温70 ℃(1 min)，以40 ℃/min速度升温至200 ℃(20 min)，再以5 ℃/min速度升温至230 ℃(25 min)。进样器温度为260 ℃，检测器温度为270 ℃，载气为氦气，流速为2 mL/min。

1.7 数据统计与分析

使用Excel 2019整理试验数据，采用SPSS 26.0软件的ANOVA程序进行单因素方差分析，并用最小显著差异(LSD)法进行多重比较，试验数据用平均值±标准差表示，以P < 0.05表示差异显著，以0.05 < P < 0.10表示差异具有显著性趋势。使用GraphPad Prism 8.3.0软件对母猪和仔猪血清脂质代谢指标和脂肪酸含量进行Pearson相关性分析。

2 结果 2.1 饲粮中添加膨化苜蓿草粉-亚麻籽对母猪初乳成分的影响

由表 4可知，与对照组相比，试验Ⅰ组的初乳中乳糖含量有升高的趋势(P=0.090)，试验Ⅱ组和试验Ⅲ组的初乳中乳蛋白含量显著升高(P < 0.05)，试验Ⅱ组的初乳中总固形物含量有升高的趋势(P=0.099)。

表 4 饲粮中添加膨化苜蓿草粉-亚麻籽对母猪初乳成分的影响 Table 4 Effects of extruded alfalfa meal-flaxseed supplementation in diets on colostrum composition of sows (n=4)

表 5 饲粮中添加膨化苜蓿草粉-亚麻籽对母猪血清脂质代谢指标的影响 Table 5 Effects of extruded alfalfa meal-flaxseed supplementation in diets on serum lipid metabolism indexes of sows (n=4)

表 6 饲粮中添加膨化苜蓿草粉-亚麻籽对仔猪血清脂质代谢指标的影响 Table 6 Effects of extruded alfalfa meal-flaxseed supplementation in diets on serum lipid metabolism indexes of piglets (n=4)

表 7 饲粮中添加膨化苜蓿草粉-亚麻籽对母猪血清脂肪酸含量的影响 Table 7 Effects of extruded alfalfa meal-flaxseed supplementation in diets on serum fatty acid contents of sows (n=4)

项目 Items	对照组 Control group	试验Ⅰ组 Trial group Ⅰ	试验Ⅱ组 Trial group Ⅱ	试验Ⅲ组 Trial group Ⅲ
亚油酸LA (C24∶1)/(ng/mL)	1 559.46±138.40^a	1 286.55±100.93^b	1 192.15±164.55^b	1 036.15±98.97^b
花生四烯酸AA (C20∶4n-6)/(ng/mL)	898.28±112.03^a	746.78±106.22^ab	592.72±87.78^b	612.75±67.56^b
二十碳五烯酸EPA (C20∶5n-3)/(ng/mL)	19.83±1.60^c	30.41±3.70^b	57.94±7.89^a	37.10±5.14^b
二十二碳六烯酸DHA (C22∶6n-3)/(ng/mL)	8.09±0.90^c	10.89±1.07^b	13.71±1.82^a	9.81±1.02^bc
二十二碳五烯酸DPA (C22∶5n-3)/(ng/mL)	9.56±0.95^c	11.65±1.10^b	14.43±1.20^a	12.42±1.02^ab
α-亚麻酸ALA (C18∶3n)/(ng/mL)	91.73±6.77^b	116.43±16.59^b	183.64±18.55^a	175.50±28.50^a
二十碳二烯酸EA (C20∶2n)/(ng/mL)	42.90±3.60^a	37.70±3.32^ab	33.07±1.77^b	41.38±7.98^ab
饱和脂肪酸SFA/(ng/mL)	5 058.88±698.01^a	4 369.62±584.87^ab	3 385.63±430.06^b	3 291.46±446.19^b
不饱和脂肪酸UFA/(ng/mL)	4 834.61±511.00	5 591.67±588.11	5 194.49±524.37	5 093.54±424.84
不饱和脂肪酸/饱和脂肪酸 UFA/SFA	0.96±0.09^b	1.30±0.29^ab	1.54±0.17^a	1.57±0.32^a
单不饱和脂肪酸MUFA/(ng/mL)	2 925.08±374.45	3 248.61±379.29	2 887.37±293.14	3 141.84±304.17
多不饱和脂肪酸PUFA/(ng/mL)	1 909.54±207.70^b	2 343.07±298.18^a	2 307.11±231.23^ab	1 951.69±120.67^ab
n-6多不饱和脂肪酸n-6 PUFA/(ng/mL)	2 457.74±217.28^a	2 033.33±179.42^b	1 784.87±221.87^b	1 648.90±166.53^b
n-3多不饱和脂肪酸n-3 PUFA/(ng/mL)	129.21±9.52^b	169.37±20.39^b	269.72±25.81^a	234.83±33.41^a
n-6多不饱和脂肪酸/n-3多不饱和脂肪酸 n-6 PUFA/n-3 PUFA	19.07±1.88^a	12.04±0.63^b	6.62±0.57^c	7.08±0.87^c

表 8 饲粮中添加膨化苜蓿草粉-亚麻籽对仔猪血清脂肪酸含量的影响 Table 8 Effects of extruded alfalfa meal-flaxseed supplementation in diets on serum fatty acid contents of piglets (n=4)

项目 Items	对照组 Control group	试验Ⅰ组 Trial group Ⅰ	试验Ⅱ组 Trial group Ⅱ	试验Ⅲ组 Trial group Ⅲ
亚油酸LA (C18∶2n-6)/(ng/mL)	889.80±26.80^a	775.40±29.46^b	705.65±37.15^b	758.79±63.39^b
花生四烯酸AA (C20∶4n-6)/(ng/mL)	887.77±53.27^a	717.00±83.45^b	677.01±93.18^b	678.00±61.05^b
二十碳五烯酸EPA (C20∶5n-3)/(ng/mL)	10.09±0.99^d	14.77±2.18^c	47.63±3.15^a	34.98±1.90^b
二十二碳六烯酸DHA (C22∶6n-3)/(ng/mL)	56.43±8.77^b	58.30±5.27^b	87.50±24.13^a	58.68±7.73^b
二十二碳五烯酸DPA (C22∶5n-3)/(ng/mL)	13.78±0.90^b	15.23±1.72^b	31.80±3.28^a	17.23±2.75^b
α-亚麻酸ALA (C18∶3n-3)/(ng/mL)	101.83±14.51^c	151.00±11.53^bc	455.00±120.88^a	256.50±55.12^b
二十碳二烯酸EA (C20∶2)/(ng/mL)	22.40±2.86^a	18.47±5.49^a	19.68±4.22^a	10.19±2.64^b
饱和脂肪酸SFA/(ng/mL)	4 804.29±106.33^a	4 369.04±411.58^ab	3 998.59±469.33^b	3 975.85±177.73^b
不饱和脂肪酸UFA/(ng/mL)	3 456.65±151.84^b	3 576.59±796.87^b	4 696.55±642.81^a	3 666.03±198.13^b
不饱和脂肪酸/饱和脂肪酸UFA/SFA	0.72±0.02^b	0.82±0.17^b	1.18±0.14^a	0.92±0.03^b
单不饱和脂肪酸MUFA/(ng/mL)	1 586.00±133.71^b	1 613.94±210.71^b	2 058.70±409.45^a	1 887.87±113.80^b
多不饱和脂肪酸PUFA/(ng/mL)	1 870.65±31.37^b	1 962.65±670.34^ab	2 637.85±233.36^a	1 778.16±114.99^b
n-6多不饱和脂肪酸n-6 PUFA/(ng/mL)	1 777.57±80.07^a	1 492.40±112.91^b	1 382.66±80.06^b	1 436.79±107.77^b
n-3多不饱和脂肪酸n-3 PUFA/(ng/mL)	182.12±25.17^c	239.30±18.64^bc	621.93±151.44^a	367.38±67.50^b
n-6多不饱和脂肪酸/n-3多不饱和脂肪酸 n-6 PUFA/n-3 PUFA	9.87±1.27^a	6.24±0.12^b	2.30±0.47^d	3.97±0.54^c

2.2 饲粮中添加膨化苜蓿草粉-亚麻籽对母猪血清脂质代谢指标的影响

由表 5可知，与对照组相比，试验Ⅱ组的母猪血清中LDL-C含量有降低的趋势(P=0.089)。各组之间母猪血清中TC、TG和HDL-C含量虽无显著差异(P>0.05)，但与对照组相比，试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的母猪血清中TC含量分别降低了9.56%、12.14%和8.35%，血清中TG含量分别降低了9.02%、27.05%和13.13%，血清中HDL-C含量分别升高了22.08%、27.70%和18.18%。

2.3 饲粮中添加膨化苜蓿草粉-亚麻籽对仔猪血清脂质代谢指标的影响

由表 6可知，与对照组相比，试验Ⅱ组的仔猪血清中LDL-C含量显著降低(P < 0.05)，血清中TC含量有降低的趋势(P=0.081)。各组之间仔猪血清中TC和HDL-C含量虽无显著差异(P>0.05)，但与对照组相比，试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的仔猪血清中TC含量分别下降了6.95%、18.97%和15.33%，血清中HDL-C含量分别升高了13.36%、22.95%和27.40%。

2.4 饲粮中添加膨化苜蓿草粉-亚麻籽对母猪血清脂肪酸含量的影响

由表 7可知，与对照组相比，试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的母猪血清中亚油酸(LA)、n-6多不饱和脂肪酸(PUFA)含量和n-6多不饱和脂肪酸/n-3多不饱和脂肪酸(n-6 PUFA/n-3 PUFA)显著降低(P < 0.05)，血清中二十碳五烯酸(EPA)和二十二碳五烯酸(DPA)含量显著升高(P < 0.05)；试验Ⅱ组和试验Ⅲ组的血清中花生四烯酸(AA)和饱和脂肪酸(SFA)含量显著降低(P < 0.05)，血清中ALA、n-3多不饱和脂肪酸(n-3 PUFA)含量和不饱和脂肪酸/饱和脂肪酸(UFA/SFA)显著升高(P < 0.05)；试验Ⅰ组和试验Ⅱ组的血清中二十二碳六烯酸(DHA)含量显著升高(P < 0.05)；试验Ⅱ组的血清中二十碳二烯酸(EA)含量显著降低(P < 0.05)；试验Ⅰ组的血清中多不饱和脂肪酸(PUFA)含量显著升高(P < 0.05)，试验Ⅱ组的血清中PUFA含量有升高的趋势(P=0.061)。

2.5 饲粮中添加膨化苜蓿草粉-亚麻籽对仔猪血清脂肪酸含量的影响

由表 8可知，与对照组相比，试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的仔猪血清中LA、AA、n-6 PUFA含量和n-6 PUFA/n-3 PUFA显著降低(P < 0.05)，血清中EPA含量显著升高(P < 0.05)；试验Ⅱ组的血清中DHA、DPA、不饱和脂肪酸(UFA)、单不饱和脂肪酸(MUFA)、PUFA、n-3 PUFA含量和UFA/SFA显著升高(P < 0.05)；试验Ⅱ组和试验Ⅲ组的血清中ALA含量显著升高(P < 0.05)，血清中SFA含量显著降低(P < 0.05)；试验Ⅲ组的血清中n-3 PUFA含量显著升高(P < 0.05)，血清中EA含量显著降低(P < 0.05)，血清中UFA/SFA有升高的趋势(P=0.061)。

2.6 母猪和仔猪血清脂质代谢指标的相关性分析

由表 9可知，母猪血清中HDL-C含量与仔猪血清中TC和TG含量呈显著负相关(P < 0.05)，与仔猪血清中HDL-C含量呈显著正相关(P < 0.05)；母猪血清中LDL-C含量与仔猪血清中GLU和HDL-C含量呈显著负相关(P < 0.05)，与仔猪血清中TC、TG和LDL-C含量呈显著正相关(P < 0.05)。

表 9 母猪和仔猪血清脂质代谢指标的相关性分析 Table 9 Correlation analysis of serum lipid metabolism indexes between sows and piglets

2.7 母猪和仔猪血清脂肪酸含量的相关性分析

由表 10可知，母猪血清中AA、SFA含量和n-6 PUFA/n-3 PUFA与仔猪血清中SFA含量和n-6 PUFA/n-3 PUFA呈显著正相关(P < 0.05)，与仔猪血清中EPA、ALA含量和UFA/SFA呈显著负相关(P < 0.05)；母猪血清中EPA、DHA、DPA、ALA和n-3 PUFA含量与仔猪血清中EPA、DHA、DPA、ALA、UFA、n-3 PUFA含量和UFA/SFA呈显著正相关(P < 0.05)，与仔猪血清中n-6 PUFA/n-3 PUFA呈显著负相关(P < 0.05)；母猪血清中UFA/SFA与仔猪血清中EPA、ALA、MUFA、n-3 PUFA含量和UFA/SFA呈显著正相关(P < 0.05)，与仔猪血清中SFA含量和n-6 PUFA/n-3 PUFA呈显著负相关(P < 0.05)；母猪血清中PUFA含量与仔猪血清中DHA、UFA、PUFA含量呈显著正相关(P < 0.05)；母猪血清中n-6 PUFA含量与仔猪血清中SFA含量和n-6 PUFA/n-3 PUFA呈显著正相关(P < 0.05)，与仔猪血清中EPA含量呈显著负相关(P < 0.05)。

表 10 母猪和仔猪血清脂肪酸含量的相关性分析 Table 10 Correlation analysis of serum fatty acid contents between sows and piglets

仔猪 Piglets	母猪Sows
仔猪 Piglets	花生四烯酸 AA	二十碳五烯酸 EPA	二十二碳六烯酸 DHA	二十二碳五烯酸 DPA	α-亚麻酸 ALA	饱和脂肪酸 SFA	不饱和脂肪酸 UFA	不饱和脂肪酸/饱和脂肪酸 UFA/SFA	单不饱和脂肪酸 MUFA	多不饱和脂肪酸 PUFA	n-6多不饱和脂肪酸 n-6 PUFA	n-3多不饱和脂肪酸 n-3 PUFA	n-6多不饱和脂肪酸/ n-3多不饱和脂肪酸 n-6 PUFA/ n-3 PUFA
亚油酸LA	0.358	0.134	0.049	-0.020	0.014	0.200	-0.248	-0.234	-0.382	-0.013	0.492	0.045	0.313
花生四烯酸AA	0.240	0.382	0.268	0.182	0.106	0.046	-0.172	-0.085	-0.443	0.199	0.401	0.188	0.157
二十碳五烯酸EPA	-0.736^*	0.927^*	0.706^*	0.854^*	0.925^*	-0.776^*	0.063	0.705^*	-0.121	0.259	-0.676^*	0.953^*	-0.866^*
二十二碳六烯酸 DHA	-0.272	0.775^*	0.710^*	0.664^*	0.612^*	-0.318	0.378	0.437	0.063	0.630^*	-0.060	0.684^*	-0.416
二十二碳五烯酸 DPA	-0.496	0.939^*	0.819^*	0.817^*	0.737^*	-0.534	0.162	0.533	-0.157	0.485	-0.343	0.825^*	-0.626^*
α-亚麻酸ALA	-0.580^*	0.943^*	0.800^*	0.853^*	0.853^*	-0.624^*	0.237	0.642^*	-0.013	0.456	-0.454	0.910^*	-0.735^*
二十碳二烯酸EA	0.585	-0.040	0.074	-0.085	-0.273	0.458	0.081	-0.334	-0.199	0.384	0.779	-0.207	0.511
饱和脂肪酸SFA	0.933^*	-0.619^*	-0.500	-0.569	-0.601^*	0.804^*	-0.163	-0.730^*	-0.120	-0.162	0.902^*	-0.626^*	0.796^*
不饱和脂肪酸 UFA	-0.313	0.803^*	0.644^*	0.711^*	0.692^*	-0.459	0.286	0.522	-0.085	0.631^*	-0.123	0.748^*	-0.500
不饱和脂肪酸/ 饱和脂肪酸 UFA/SFA	-0.670^*	0.938^*	0.764^*	0.843^*	0.818^*	-0.726^*	0.258	0.732^*	-0.061	0.552	-0.498	0.882^*	-0.749^*
单不饱和脂肪酸 MUFA	-0.437	0.744^*	0.543	0.648^*	0.782^*	-0.544	0.408	0.650^*	0.194	0.531	-0.269	0.792^*	-0.584^*
多不饱和脂肪酸 PUFA	-0.183	0.708^*	0.602^*	0.634^*	0.522	-0.331	0.163	0.356	-0.246	0.590^*	-0.012	0.598^*	-0.365
n-6多不饱和脂肪酸 n-6 PUFA	0.304	0.269	0.167	0.087	0.063	0.123	-0.213	-0.161	-0.424	0.099	0.455	0.122	0.237
n-3多不饱和脂肪酸 n-3 PUFA	-0.571	0.943^*	0.798^*	0.849^*	0.847^*	-0.615^*	0.237	0.635^*	-0.021	0.465	-0.439	0.905^*	-0.725^*
n-6多不饱和脂肪酸/ n-3多不饱和脂肪酸 n-6 PUFA/n-3 PUFA	0.792^*	-0.836^*	-0.729^*	-0.862^*	-0.875^*	0.747^*	-0.324	-0.769^*	-0.134	-0.446	0.771^*	-0.896^*	0.953^*

表 10 母猪和仔猪血清脂肪酸含量的相关性分析 Table 10 Correlation analysis of serum fatty acid contents between sows and piglets

3 讨论

初乳是哺乳仔猪能量和蛋白质的直接来源，乳成分的变化在一定程度上反映了乳腺机能的变化，直接影响着哺乳仔猪的生长发育和机体健康^[20-21]。乳蛋白主要由乳腺通过一定的机制从血液中摄取氨基酸来合成，乳糖和乳脂主要通过摄取血液中的葡萄糖和脂肪酸合成^[22-23]。Obeidat等^[24]研究表明，与麦秸相比，苜蓿干草可以提高母羊乳中乳蛋白、乳糖和总固形物含量，满足母羊泌乳的营养需要。Wang等^[25]报道，与谷物秸秆相比，苜蓿干草可以增加奶牛乳中的乳脂、乳糖、乳蛋白和总固形物含量。Farmer等^[26]研究发现，与标准饲粮相比，在妊娠后期和哺乳期母猪饲粮中添加亚麻籽提高了初乳中乳蛋白和乳糖含量，进而可以使新生仔猪从初乳中获得足够的母体免疫球蛋白以进行被动免疫保护^[27-28]。Zhang等^[29]和Kholif等^[30]研究表明，与对照饲粮相比，添加亚麻籽增加了羊乳中亚麻酸和n-3 PUFA等有益脂肪酸的含量，改善了母乳的脂肪酸组成，同时还提高了乳脂、乳糖和乳蛋白含量，改善了乳品质。潘培颖等^[31]和苏莹莹等^[32]研究发现，添加膨化苜蓿草粉-亚麻籽可以增加哺乳期平均日采食量，提高母猪血清中催乳素含量，改善母猪的泌乳能力。本研究同样发现，在母猪饲粮中添加膨化苜蓿草粉-亚麻籽可以提高初乳中乳脂、乳糖、乳蛋白和总固形物含量，这可能是因为苜蓿草粉和亚麻籽中含有的黄酮类和木脂素类物质具有弱雌激素作用，可以提高体内胰岛素生长因子-Ⅰ含量，进而调节机体蛋白质代谢和脂质代谢，促进细胞生长分化(有丝分裂原)，刺激RNA、DNA的合成和细胞增殖，抑制细胞凋亡等^[33]；同时，胰岛素生长因子-Ⅰ可直接通过其受体作用于乳腺，对乳腺最终分化完全、发育成熟、乳汁生成以及新生儿的生长发育有调控作用^[34]。

GLU是动物进行生命活动的直接供能物质，其含量升高会促进胰岛素的分泌，进而影响细胞膜的转运和细胞对氨基酸和GLU的摄取，增加体内蛋白质和糖原的合成，反映了机体的能量代谢水平^[35-36]。血清中TC和TG含量反映了机体脂类合成、吸收和代谢的情况，含量过高时会引起血脂水平异常、异位脂质沉积等，进而引起一系列代谢性疾病，如肥胖、非酒精性脂肪肝和Ⅱ型糖尿病^[37-39]；HDL-C可以将外周组织和血液中多余的胆固醇运送至肝脏，并加工成胆汁酸后经肠道排出体外^[40]；LDL-C可以将肝脏合成的内源性胆固醇运送至肝脏外组织，其含量过高会引起局部炎症反应，导致动脉粥样硬化^[41]。王成章等^[42]研究发现，苜蓿皂苷可以降低仔猪血清中TC和LDL-C含量，增加血清中HDL-C含量，从而降低了血液中胆固醇的沉积。Chen等^[37]研究表明，苜蓿黄酮可以降低扬州鹅血清中TC、TG和LDL-C含量，增加血清中HDL-C含量，促进了胆固醇代谢，有利于维持动物的机体健康。Mir等^[43]研究报道，亚麻籽可以降低肉鸡血清中TC和TG含量，而对血清中GLU含量无显著影响。Thakur等^[44]研究发现，亚麻籽胶降低了Ⅱ型糖尿病患者血清中TC、TG、低密度脂蛋白(LDL)和极低密度脂蛋白(VLDL)含量，减轻了糖尿病合并血脂异常的临床症状。本研究结果表明，膨化苜蓿草粉-亚麻籽降低了母猪和仔猪血清中TC、TG、LDL-C含量，提高了血清中HDL-C含量，其中以10%添加水平效果较好。推测膨化苜蓿草粉-亚麻籽对动物机体的脂质代谢具有积极影响可能有以下原因：首先，苜蓿草粉中含有的生物活性因子(皂苷、黄酮等)作为具有重要药理作用的次生代谢产物，已被证明可以促进胆固醇代谢，减少体内脂肪沉积，从而改善脂质代谢^[37]；其次，亚麻籽可以通过增加肠腔内黏度、阻碍胶束形成、减少脂质摄取和抑制胆汁酸的重吸收来调节胆汁酸代谢，促进肝脏中胆固醇的分解，从而降低血清中TC含量^[43]，同时，亚麻籽中含有丰富的n-3 PUFA，众多研究也表明，n-3 PUFA可以通过加强脂肪动员，降低脂类生成相关基因和蛋白质的表达水平，调节线粒体的功能和内质网应激来调节机体的脂质代谢^[45-46]。

脂肪酸是一类具有重要生理功能的生物活性分子，与许多疾病的发生和发展密切相关^[47]。SFA会引起血清中LDL含量增加，导致脂质代谢异常，危害机体健康；MUFA可以降低血清中LDL的氧化敏感性，从而保护血管内皮功能，对机体血脂质代谢具有积极影响^[48]；PUFA(包括n-3 PUFA和n-6 PUFA)是维持动物生长发育和机体健康的重要营养素^[49]，尤其是n-3 PUFA(如DHA、EPA和DPA)作为促炎症消退脂类介质的前体物质，可以通过减轻中性粒细胞浸润和促进巨噬细胞从炎症组织向淋巴结的流动来减轻脂肪炎症，缓解脂质代谢紊乱引起的代谢综合征^[50-51]。亚麻籽是n-3 PUFA的主要来源^[52]，其富含的ALA是合成2种对机体具有重要益生作用的n-3 PUFA(EPA和DHA)的前体物质^[53]。本课题组前期曾对母乳中的脂肪酸组成进行了测定，结果表明，添加膨化苜蓿草粉-亚麻籽增加了母乳中ALA、DHA、MUFA、UFA含量和UFA/SFA^[31]。本试验在前期研究基础上，进一步测定了膨化苜蓿草粉-亚麻籽对母猪和仔猪血清脂肪酸含量的影响，以探讨母乳以及血清脂肪酸含量对母仔猪机体健康的作用。与前期研究结果相似，本研究同样发现，膨化苜蓿草粉-亚麻籽也增加了母猪和仔猪血清中ALA、DHA、EPA、UFA、MUFA、PUFA和n-3 PUFA含量以及UFA/SFA和n-3 PUFA/n-6 PUFA，这可能与母仔间营养物质的垂直传递有关。Sanders等^[54]研究发现，连续2周每天摄入20 mL亚麻籽油显著增加了人体血浆脂质和血小板磷脂中EPA含量。Renaud等^[55]在法国农民的饮食中用菜籽油和富含ALA的人造黄油替代黄油，同样发现血浆脂质和血小板磷脂中EPA含量显著增加。Huang等^[56]研究也表明，膨化亚麻籽显著提高了蛋鸡血浆中ALA、DHA和n-3 PUFA含量，显著降低了血浆中AA、n-6 PUFA含量和n-6 PUFA/n-3 PUFA。Baidoo等^[57]报道，在母猪饲粮中添加10%的亚麻籽后能提高母乳中UFA和n-3 PUFA含量，降低n-6 PUFA/n-3 PUFA，同时提高了仔猪血清中n-3 PUFA含量。毛丽梅^[58]和周婷婷^[59]研究发现，n-3 PUFA/n-6 PUFA升高有利于促进子代的生长发育和免疫系统的成熟，且相关性分析表明，孕妇膳食中EPA和DHA的摄入量与孕妇和胎儿血清中EPA和DHA含量呈正相关。由此可见，饲粮中添加膨化苜蓿草粉-亚麻籽可以改善母猪和仔猪血清脂肪酸组成，提高血清中有益脂肪酸含量，这可能与哺乳仔猪能够通过乳汁来获得必需脂肪酸，进而改善其营养物质代谢和机体健康有关^[60-61]。

通过进一步对母猪和仔猪的血清脂质代谢指标与脂肪酸含量进行相关性分析发现，饲粮中添加膨化苜蓿草粉-亚麻籽改善了母猪的脂质代谢，降低了血清中LDL-C含量，同时血清的脂肪酸组成也发生改变，DHA、DPA、EPA等有益于胎儿和婴儿生长发育的n-3 PUFA含量增加，从而可以在一定程度上改善了现代高产母猪的部分繁殖障碍问题。相应地，新生仔猪从母乳中摄取能量、蛋白质和脂肪酸等来维持自身的机体代谢并获得被动免疫，血清中TC、TG和LDL-C含量降低，DHA、DPA、EPA和ALA等n-3 PUFA含量增加。这提示膨化苜蓿草粉-亚麻籽可以通过改善母猪的营养物质代谢和血清脂肪酸组成来改善仔猪的机体健康。

4 结论

饲粮中添加膨化苜蓿草粉-亚麻籽可以提高母猪初乳品质，改善母猪和仔猪的血清脂质代谢和脂肪酸组成。在本试验条件下，饲粮中膨化苜蓿草粉-亚麻籽的适宜添加水平为10%。

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