Effects of conjugated linoleic acid supplementation and feeding level on dairy performance, milk fatty acid composition, and body fat changes in mid-lactation goats
Effects of conjugated linoleic acid supplementation and feeding level on dairy performance, milk fatty acid composition, and body fat changes in mid-lactation goats
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DOI：
10.3168/jds.2014-8364
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发表时间：
2014-11-01
影响因子：
3.5
通讯作者：
Schmidely, P.
中科院分区：
文献类型：
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作者：
Ghazal, S.;Berthelot, V.;Schmidely, P.
本试验旨在研究脂包裹共轭亚油酸(CLA，4.5g顺式-9，反式-11C18：2和4.5g反式-10，顺式-12C18：2)与饲喂水平之间的交互作用，以检验CLA与饲喂水平之间的交互作用是否会影响奶牛的产奶性能或乳脂肪酸(FA)谱。24只奶山羊进行了8周的试验，其中3周适应于试验日粮，日粮中含有玉米青贮料、甜菜浆、大麦和商品精料。在第三周，根据干物质采食量(DMI)、原料奶产量和脂肪产量将山羊分成两组。每组随机分为对照组(45g棕榈油钙盐/d)或共轭亚油酸处理组。在每一块中，一只山羊被饲喂到100%(FL100)的计算能量需要量，另一只山羊被饲喂到第一只山羊(FL85)体重指数的85%。每周记录个体产奶量和乳成分，并在第3、5和7周分析乳脂肪酸组成。添加共轭亚油酸使乳脂含量和产脂量分别降低17%和19%，与饲喂水平无关。它既减少了乳汁FA从头合成的分泌量，也减少了从血液中摄取的分泌量。共轭亚油酸与饲喂水平对乳汁分泌无交互作用。添加共轭亚油酸对DMI、产奶量、蛋白质和乳糖产量没有影响，但提高了计算的泌乳平衡净能量。饲喂Fl100×CLA日粮的山羊具有最高的DMI和蛋白质产量。共轭亚油酸与饲喂水平之间的交互作用对其他变量均不显著。与饲喂FL100的山羊相比，饲喂FL85的山羊具有较低的DMI、较低的泌乳平衡净能和较低的肠道可消化蛋白质含量。体重、产奶量、乳脂、蛋白质和乳糖产量以及乳中脂肪、蛋白质、乳糖和尿素含量不受饲喂水平的影响。综上所述，在低饲喂水平下，由于能量和氨基酸的同时短缺，在低饲喂水平下，通过添加共轭亚油酸而减少的能量没有被分配给乳糖或蛋白质。在高饲喂水平的山羊中，剩余的能量倾向于分配给乳蛋白产量，同时防止过多的脂肪动员。
The objective of this trial was to study the interaction between the supplementation of lipid-encapsulated conjugated linoleic acid (CLA; 4.5 g of cis-9,trans-11 C18:2 and 4.5 g of trans-10,cis-12 C18:2) and feeding level to test if milk performance or milk fatty acid (FA) profile are affected by the interaction between CLA and feeding level. Twenty-four dairy goats were used in an 8-wk trial with a 3-wk adaptation to the experimental ration that contained corn silage, beet pulp, barley, and a commercial concentrate. During the third week, goats were assigned into blocks of 2 goats according to their dry matter intake (DMI), raw milk yield, and fat yield. Each block was randomly allocated to control (45 g of Ca salt of palm oil/d) or CLA treatment. Within each block, one goat was fed to cover 100% (FL100) of the calculated energy requirements and the other was fed 85% of the DMI of the first goat (FL85). Individual milk production and composition were recorded weekly, and milk FA composition was analyzed in wk 3, 5, and 7. Conjugated linoleic acid supplementation reduced milk fat content and fat yield by 17 and 19%, respectively, independent of the feeding level. It reduced both the secretion of milk FA synthesized de novo, and those taken up from the blood. No interaction between CLA and feeding level was observed on milk secretion of any group of FA. The CLA supplementation had no effect on DMI, milk yield, protein, and lactose yields but it improved calculated net energy for lactation balance. Goats fed the FL100 x CLA diet tended to have the highest DMI and protein yield. The interaction between CLA and feeding level was not significant for any other variables. Compared with the goats fed FL100, those fed FL85 had lower DMI, lower net energy for lactation balance, and lower digestible protein in the intestine balance. The body weight; milk yield; milk fat, protein, and lactose yields; and fat, protein, lactose, and urea contents in milk were not affected by feeding level. In conclusion, reduction in energy spared via fat yield reduction after CLA supplementation was not partitioned toward milk lactose or protein in goats at a low feeding level, possibly because of a simultaneous shortage of energy and amino acids. In goats on the high feeding level, energy spared tended to be partitioned toward milk protein yield, and at the same time to the prevention of excessive lipid mobilization.