Effect of trace minerals and starch on digestibility and rumen fermentation in diets for dairy heifers.
Effect of trace minerals and starch on digestibility and rumen fermentation in diets for dairy heifers.
复制标题
微量矿物质和淀粉对奶牛日粮消化率和瘤胃发酵的影响。
DOI：
10.3168/jds.2015-10034
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发表时间：
2016
影响因子：
3.5
通讯作者：
A. Heinrichs
中科院分区：
文献类型：
--
作者：
F. Pino;A. Heinrichs
本试验旨在评价乳母牛日粮中添加不同形式的微量矿物质（TM）和使用不同淀粉水平对瘤胃发酵和消化率的影响。选取8头瘤胃空心乳牛（15.4±0.8月龄，438.31±18.08 kg体重），采用4 × 4拉丁方分割图设计，每隔19 d进行试验，其中15d为适应期，4d为采样期。全图因子为TM类型；有机化合物为蛋白质酸盐（OTM）或无机硫酸盐（ITM），亚图为淀粉水平（3.54%,12.95,22.25和31.73%）。在第15 ~ 19天完成全部粪便和尿液收集，测定消化率和TM排泄。于饲喂后0、1、2、4、8、12、16、20和22 h，于第18 ~ 19天取样瘤胃内容物，测定pH和挥发性脂肪酸（VFA）浓度。收集血浆样本，评估TM浓度和铜蓝蛋白、谷胱甘肽过氧化物酶和超氧化物歧化酶的酶活性。淀粉水平影响pH值、个体VFA浓度和营养物质排泄。与ITM相比，OTM的微量矿物质摄入量较低。TM形态对干物质消化率无影响，但随着淀粉水平的升高，饲粮干物质消化率升高。饲粮添加OTM时瘤胃pH较低，这与饲粮添加OTM时瘤胃总VFA产量和丁酸盐比例较高一致。这些变量可能是由于OTM的生物利用度更高，瘤胃微生物的利用和发酵速度更快。食用ITM的小母牛粪便中水分含量较高，尿排泄量也较高，增加了粪便总产量。不同处理的TM总排泄量无显著差异。血浆矿物质浓度除Mn外无显著差异，OTM组高于对照组。酶活性不受处理的影响。矿物质摄入量减少，血液矿物质水平没有差异，表明与ITM相比，OTM的吸收增强。综上所述，从瘤胃pH、VFA产量和血浆TM浓度来看，OTM可能比ITM具有更高的瘤胃生物利用度和更大的吸收程度。此外，TM形式影响粪便水分和尿液排泄，表明ITM可能刺激水分摄入。
The objective of this study was to evaluate the effect of different forms of trace minerals (TM) and the use of different starch levels in dairy heifer diets on rumen fermentation and digestibility. Eight rumen cannulated dairy heifers (15.4 ± 0.8 mo of age and 438.31 ± 18.08 kg of body weight) were subjected to a split-plot, 4 × 4 Latin square design with 19-d periods: 15d of adaptation and 4d of sampling. The whole-plot factor was type of TM; organic as proteinates (OTM) or inorganic sulfates (ITM), and the subplot was starch level (3.54, 12.95, 22.25, and 31.73%). Total collection of feces and urine was completed on d 15 to 19 to determine digestibility and TM excretion. Rumen contents were sampled on d 18 to 19 at 0, 1, 2, 4, 8, 12, 16, 20, and 22 h after feeding to measure pH and volatile fatty acid (VFA) concentrations. Plasma samples were collected to evaluate TM concentrations and enzymatic activity for ceruloplasmin, glutathione peroxidase, and superoxide dismutase. Starch level affected pH, individual VFA concentrations, and nutrient excretion. Trace mineral intake was lower for OTM compared with ITM. No effect of TM form on dry matter digestibility was detected, but as level of starch increased, diet dry matter digestibility increased. Rumen pH was lower for diets with OTM, which is consistent with higher total VFA production and butyrate proportion observed for heifers fed OTM diets. These variables may be explained by the higher bioavailability of OTM and faster utilization and fermentation by rumen microorganisms. Heifers that consumed ITM had higher moisture in feces and higher urine excretion, which increased total manure production. Total excretion of TM was not different by treatment. Blood plasma mineral concentration was not different between treatments except for Mn, which was higher for OTM. Enzymatic activity was not affected by treatments. Mineral intake was reduced and blood mineral levels were not different, suggesting enhanced absorption of OTM compared with ITM. In conclusion, based on rumen pH, VFA production, and plasma TM concentration, OTM may be more ruminally bioavailable and absorbed to a greater extent than ITM. Also, TM form affected fecal moisture and urine excretion, suggesting that ITM may stimulate water intake.