Litherland Noah B, Beaulieu Angela Denise, Reynolds Christopher K, Drackley James K
Department of Animal Sciences, University of Illinois, Urbana, US.
School of Agriculture, Policy and Development, University of Reading, Berkshire, UK.
J Anim Physiol Anim Nutr (Berl). 2023 Jan;107(1):12-27. doi: 10.1111/jpn.13690. Epub 2022 Feb 4.
Our objective was to determine the effects of chemical structure, amount, and site of infusion of long-chain fatty acids (LCFA) in lactating dairy cows. Six multiparous Holstein cows were used in a 6 × 6 Latin square design with 21-d periods. During d 1 to 14, 250 g/d of LCFA and during d 15 to 21, 500 g/d of LCFA were infused continuously into either the rumen or abomasum. Treatments were 1) Control (CONT); 200 g/d of meat solubles plus 12 g/d of Tween 80 in 10 L of water, administered half in the rumen and half in abomasum; 2) control plus mostly saturated LCFA into the abomasum (SFAA); 3) control plus mostly saturated LCFA into the rumen (SFAR); 4) control plus soy (mostly unsaturated LCFA) free fatty acids (FFA) into the abomasum (UFAA); 5) control plus soy triglycerides (TG) into the abomasum (TGA); and 6) control plus soy TG into the rumen (TGR). The first 10 d of each period were for adaptation and washout from the previous treatment. The diet consisted of 30% (dry matter basis) corn silage, 20% alfalfa silage and 50% concentrate. Cows infused with UFAA had lower dry matter intake and milk yield than those infused with SFAA or TGA and reductions were greater at the higher infusion amount. Milk fat yield was decreased by UFAA relative to other treatments. Unsaturated LCFA decreased milk fat yield more than saturated LCFA. All LCFA treatments decreased short- and medium-chain FA in milk relative to CONT, with greatest decreases for UFAA. Apparent total tract digestibilities of nutrient fractions were decreased by UFAA compared with TGA and SFAA and tended to be lower at the higher infusion amount. Apparent digestibility of total fatty acids (FA) was greater for SFAR than for SFAA. Plasma glucagon-like peptide-1 was greater for cows infused with UFAA than SFAA or TGA and increased at the higher amount. Plasma cholecystokinin was greater for cows infused with LCFA compared with CONT. Postruminal unsaturated FFA reduced intake and digestibility of nutrients and FA compared with postruminal TG infusion; saturated FA did not decrease dry matter intake or disrupt nutrient digestion. Glucagon-like peptide-1 may be involved in regulation of feed intake by long-chain fatty acids.
我们的目标是确定化学结构、数量以及长链脂肪酸（LCFA）在泌乳奶牛体内的输注部位所产生的影响。选用6头经产荷斯坦奶牛，采用6×6拉丁方设计，每期时长21天。在第1至14天，每天向瘤胃或皱胃连续输注250克LCFA；在第15至21天，每天输注500克LCFA。处理方式如下：1）对照组（CONT）；每天在10升水中加入200克肉浸液和12克吐温80，一半经瘤胃、一半经皱胃给药；2）对照组加主要为饱和LCFA经皱胃输注（SFAA）；3）对照组加主要为饱和LCFA经瘤胃输注（SFAR）；4）对照组加大豆（主要为不饱和LCFA）游离脂肪酸（FFA）经皱胃输注（UFAA）；5）对照组加大豆甘油三酯（TG）经皱胃输注（TGA）；6）对照组加大豆TG经瘤胃输注（TGR）。每个周期的前10天用于适应和清除上一处理的残留影响。日粮由30%（干物质基础）玉米青贮、20%苜蓿青贮和50%精料组成。与输注SFAA或TGA的奶牛相比，输注UFAA的奶牛干物质摄入量和产奶量较低，且在较高输注量时降幅更大。与其他处理相比，UFAA降低了乳脂产量。不饱和LCFA比饱和LCFA更能降低乳脂产量。与对照组相比，所有LCFA处理均降低了牛奶中短链和中链脂肪酸含量，其中UFAA降幅最大。与TGA和SFAA相比，UFAA降低了营养成分的表观全肠道消化率，且在较高输注量时往往更低。SFAR的总脂肪酸（FA）表观消化率高于SFAA。与输注SFAA或TGA的奶牛相比，输注UFAA的奶牛血浆胰高血糖素样肽-1含量更高，且在较高剂量时升高。与对照组相比，输注LCFA的奶牛血浆胆囊收缩素含量更高。与瘤胃后输注TG相比，瘤胃后不饱和FFA降低了营养物质和FA的摄入量及消化率；饱和FA未降低干物质摄入量或干扰营养物质消化。胰高血糖素样肽-1可能参与长链脂肪酸对采食量的调节。
