Khorasani G R, de Boer G, Robinson P H, Kennelly J J
Department of Animal Science, University of Alberta, Edmonton, Canada.
J Dairy Sci. 1992 Feb;75(2):492-501. doi: 10.3168/jds.S0022-0302(92)77786-8.
The effects of canola fat on digestion and metabolism were investigated by incorporating 0, 4.5, 9, 13.2, or 17.4% Jet-Sploded canola seed into a diet containing a 60:40 (DM) concentrate:forage ratio. The diets contained 16.5% CP, 30% alfalfa silage, and 10% whole-crop oat silage on a DM basis and were fed for ad libitum consumption as TMR to 10 ruminally cannulated Holstein cows in early lactation. Jet-Sploded canola seed supplementation did not change ruminal pH or NH3 N concentrations, but VFA concentrations declined with increasing level of inclusion. Apparent digestibilities of DM, OM, CP, NDF, and ADF were unaffected by level of inclusion of Jet-Sploded canola seed, but ether extract digestibility declined linearly, which resulted in similar ether extract absorption across the three diets supplemented with canola fat. Based on in sacco data, the percentages of ruminal digestion of OM and CP declined with increasing inclusion of Jet-Sploded canola seed. Plasma glucose and FFA concentrations tended to respond in a quadratic fashion, plasma insulin concentration declined linearly, and plasma glucagon and somatotropin concentrations were unaffected by dietary treatment. The results indicate that a positive productive response may be expected from dietary inclusion of about 5% Jet-Sploded canola seed, but the benefits of increased energy density associated with higher inclusion levels may be offset by reduced availability of energy in the rumen and decreased fat digestibility postruminally. The substantial effects of time postfeeding on ruminal fermentation and on concentrations of plasma hormone and metabolites in animals fed TMR demonstrate that infrequent sampling can result in misleading results and, thus, invalid interpretation of the influence of dietary fat on these parameters.
通过将0%、4.5%、9%、13.2%或17.4%的喷射破碎油菜籽加入到精粗比为60:40（干物质）的日粮中，研究了油菜籽脂肪对消化和代谢的影响。日粮以干物质计含有16.5%的粗蛋白、30%的苜蓿青贮和10%的全株燕麦青贮，并制成全混合日粮（TMR）自由采食，饲喂10头泌乳早期安装了瘤胃瘘管的荷斯坦奶牛。添加喷射破碎油菜籽并未改变瘤胃pH值或氨氮浓度，但随着添加水平的增加，挥发性脂肪酸（VFA）浓度下降。干物质、有机物、粗蛋白、中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）的表观消化率不受喷射破碎油菜籽添加水平的影响，但乙醚提取物消化率呈线性下降，这导致在添加了油菜籽脂肪的三种日粮中乙醚提取物的吸收量相似。根据瘤胃尼龙袋法数据，随着喷射破碎油菜籽添加量的增加，有机物和粗蛋白的瘤胃消化率百分比下降。血浆葡萄糖和游离脂肪酸（FFA）浓度呈二次曲线反应趋势，血浆胰岛素浓度呈线性下降，血浆胰高血糖素和生长激素浓度不受日粮处理的影响。结果表明，日粮中添加约5%的喷射破碎油菜籽可能会带来积极的生产反应，但随着添加水平的提高，能量密度增加带来的益处可能会被瘤胃中能量利用率降低和瘤胃后脂肪消化率下降所抵消。采食后时间对采食TMR的动物瘤胃发酵以及血浆激素和代谢物浓度有显著影响，这表明不频繁采样可能会导致误导性结果，从而对日粮脂肪对这些参数的影响做出无效解释。
