Su Xiaodong, Zhang Lei, Sun Yiyang, Wu Yanbo, Ren Jianrong, Wu Shengru, Lei Xinjian, Zhang Jun, Wang Dangdang, Ren Hao, Yao Junhu
College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Xi'an Wellhope Feed Technology Co., Ltd., Xi'an, Shaanxi, 710000, China.
J Anim Sci Biotechnol. 2025 Jan 5;16(1):3. doi: 10.1186/s40104-024-01136-y.
The diverse types and processing methods of grains intricately influence the sites and digestibility of starch digestion, thereby impacting energy utilization. This study aimed to explore the impact of grain variety and processing methods on the net energy (NE) in dairy goats, analyzing these effects at the level of nutrient digestion and metabolism.
Eighteen castrated Guanzhong dairy goats (44.25 ± 3.59 kg BW) were randomly divided into 3 groups, each consisting of 6 replicates. The substitution method was employed to determine the NE values of the dry-rolled corn (DRC), dry-rolled wheat (DRW) or steam-flaked corn (SFC, 360 g/L). Briefly, two phases were performed. Throughout the basal phase, all goats were fed the same basal diet. In the substitution phase, 30% of the basal diet was replaced with DRC, DRW and SFC, respectively.
In this study, the NE values of the DRC, DRW and SFC were 7.65, 7.54 and 7.44 MJ/kg DM, respectively. Compared to the DRC group, the DRW group showed increased digestibility of starch and crude protein (CP). Similarly, the SFC group exhibited increased organic matter (OM) and starch digestibility and a trend towards higher dry matter (DM) digestibility, reduced fecal OM and starch content. Additionally, fecal volatile fatty acid (VFA) concentrations decreased in goats fed SFC. Correspondingly, digestible energy (DE) in the DRW and SFC groups tended to be higher than in the DRC group. DRW increased total VFA concentration compared to DRC, while SFC increased the proportion of propionate and decreased the acetate-to-propionate ratio in the rumen. Both the DRW and SFC diets elevated serum glucose levels. Furthermore, heat increment (HI) and gaseous energy (GasE) related to fermentation were significantly higher in the DRW and SFC groups compared to the DRC group.
Our findings indicated that DRW and SFC increased rumen starch fermentation in goats, thereby improving total tract starch digestion and DE. However, DRW and SFC failed to improve NE value due to increased heat and gas energy production from fermentation. Therefore, excessively refined grains processing in the diet of dairy goats does not effectively improve energy efficiency.
谷物的种类繁多且加工方式各异，这对淀粉消化的部位和消化率产生复杂影响，进而影响能量利用。本研究旨在探究谷物品种和加工方式对奶山羊净能（NE）的影响，并在营养消化和代谢水平上分析这些效应。
将18只去势的关中奶山羊（体重44.25±3.59千克）随机分为3组，每组6个重复。采用替代法测定干碾压玉米（DRC）、干碾压小麦（DRW）或蒸汽压片玉米（SFC，360克/升）的NE值。简要来说，实验分为两个阶段。在基础阶段，所有山羊均饲喂相同的基础日粮。在替代阶段，分别用DRC、DRW和SFC替代基础日粮的30%。
在本研究中，DRC、DRW和SFC的NE值分别为7.65、7.54和7.44兆焦/千克干物质。与DRC组相比，DRW组的淀粉和粗蛋白（CP）消化率有所提高。同样，SFC组的有机物（OM）和淀粉消化率提高，干物质（DM）消化率有升高趋势，粪便中OM和淀粉含量降低。此外，饲喂SFC的山羊粪便挥发性脂肪酸（VFA）浓度降低。相应地，DRW组和SFC组的消化能（DE）往往高于DRC组。与DRC相比，DRW提高了总VFA浓度，而SFC提高了瘤胃中丙酸的比例并降低了乙酸与丙酸的比例。DRW和SFC日粮均提高了血清葡萄糖水平。此外，与DRC组相比，DRW组和SFC组与发酵相关的热增耗（HI）和气态能（GasE）显著更高。
我们的研究结果表明，DRW和SFC增加了山羊瘤胃淀粉发酵，从而提高了全消化道淀粉消化率和DE。然而，由于发酵产生的热和气态能增加，DRW和SFC未能提高NE值。因此，奶山羊日粮中过度精细的谷物加工并不能有效提高能量效率。
