Fat supplementation has potential to improve reproductive performance and increase pregnancy rates in cattle by increasing the energy density of the diet. However, some of the positive effects of fat seem to be influenced by the type of fatty acid fed. Docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) are long-chain n-3 poly-unsaturated fatty acids (PUFA) that have important biological effects on reproduction through their involvement in hormone and series 3 prostaglandin synthesis. Ruminant tissues are naturally almost devoid of n-3 long-chain PUFA, specifically EPA and DHA. Algae biomass provides a consistent source of DHA and EPA that could be fed to alter hormonal profiles and improve reproduction of beef heifers. Eighty-eight Angus × Simmental heifers (427 ± 1.8 kg BW) were blocked by BW and allotted to 2 treatments (44/treatment, 4 pens/treatment, 11 heifers/pen). Control heifers were fed a diet that contained (DM basis) 52.8% mixed grass silage, 32% corn silage, and 15.2% concentrate. DHAgold™ (49% fat; 21.8% DHA; DSM Inc.) was included in the algae diet at 1.65% of DM, replacing equal parts of corn and DDGS. Diets were formulated to contain 12% CP and 0.85 Mcal/kg NEg. Heifers were fed treatment diets from 54 d prior to the breeding season through the first trimester. Follicular fluid was collected on day 47 for hormonal analysis. Artificial insemination (AI) was from d 54 to 77. Heifers that did not get pregnant to AI were removed from the study on d 109 and placed with a bull. The study ended on d 180. Data were analyzed using the MIXED procedure of SAS. During the pre-breeding period, algae heifers had lesser DMI (P=0.006) compared to control heifers. Heifers supplemented with algae had greater ADG (P=0.03) during the breeding period and BW tended (P=0.06) to be greater for algae compared to control heifers on d 98 and was greater on d 180 (P=0.03). Dominant follicle diameter and follicular estrogen concentration were unaffected by treatment (P≥0.12). Follicular insulin-like growth factor-1 was greater in algae compared to control heifers (P=0.03). First service conception rate did not differ between treatments (P=0.67); however, second service and overall conception were lesser (P≤0.03) in algae compared to control heifers. These data suggest supplementing DHA-rich algae improved growth but decreased conception rates of primiparous beef females.

中文翻译：

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在繁殖和早期妊娠第一头小母牛中补充藻类对生长和繁殖的影响


脂肪补充剂有可能通过增加饮食的能量密度来改善牛的繁殖性能和提高怀孕率。然而，脂肪的一些积极影响似乎受到喂养的脂肪酸类型的影响。二十二碳六烯酸 （DHA， 22：6n-3） 和二十碳五烯酸 （EPA， 20：5n-3） 是长链 n-3 多不饱和脂肪酸 （PUFA），通过参与激素和 3 系列前列腺素合成对生殖具有重要的生物学效应。反刍动物组织自然几乎不含 n-3 长链 PUFA，特别是 EPA 和 DHA。藻类生物质提供了 DHA 和 EPA 的稳定来源，可以喂食以改变荷尔蒙状况并改善肉牛小母牛的繁殖。88 头安格斯×西门塔尔小母牛 （427 ± 1.8 kg BW） 被 BW 封闭并分配到 2 个处理 （44/治疗，4 个围栏/治疗，11 头小母牛/围栏）。对照小母牛饲喂含有（以 DM 为基础）52.8% 混合草青贮饲料、32% 玉米青贮饲料和 15.2% 精饲料的日粮。DHAgold™（49% 脂肪;21.8% DHA;帝斯曼公司）以 1.65% 的 DM 包含在藻类饮食中，取代了等量的玉米和 DDGS。日粮配制为含有 12% CP 和 0.85 Mcal/kg NEg。从繁殖季节前 54 天到妊娠早期，小母牛饲喂处理日粮。第 47 天收集滤泡液用于激素分析。人工授精 （AI） 从 d 54 到 77。未因 AI 而怀孕的小母牛于 d 109 从研究中取出，并与公牛一起放置。该研究于 180 天结束。使用 SAS 的 MIXED 程序分析数据。在繁殖前，与对照小母牛相比，藻类小母牛的 DMI 较低 （P=0.006）。补充藻类的小母牛具有更高的 ADG （P=0.03） 在繁殖期间，与对照小母牛相比，藻类的 BW 往往 （P=0.06） 在 d 98 更大，在 d 180 更高 （P=0.03）。优势卵泡直径和卵泡雌激素浓度不受治疗影响 （P≥0.12）。与对照小母牛相比，藻类中的滤泡胰岛素样生长因子-1 更高 （P=0.03）。首次服务受孕率在治疗之间没有差异 （P=0.67）;然而，与对照小母牛相比，藻类的第二次服务和总体受孕率较低 （P≤0.03）。这些数据表明，补充富含 DHA 的藻类可以改善初产牛肉雌性的生长，但会降低受孕率。