Ricci Sara, Rivera-Chacon Raul, Petri Renee M, Sener-Aydemir Arife, Sharma Suchitra, Reisinger Nicole, Zebeli Qendrim, Castillo-Lopez Ezequias
Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
Christian Doppler Laboratory for Innovative Gut Health Concepts of Livestock, Vienna, Austria.
Front Physiol. 2021 Jun 3;12:645529. doi: 10.3389/fphys.2021.645529. eCollection 2021.
Saliva facilitates feed ingestion, nutrient circulation, and represents an important pH buffer for ruminants, especially for cattle fed high-concentrate diets that promote rumen acidification. This experiment evaluated the short-term effects of nine phytogenic compounds on salivation, saliva physico-chemical composition as well as ingested feed boli characteristics in cattle. A total of nine ruminally cannulated Holstein cows were used. Each compound was tested in four of these cows as part of a high-concentrate meal (2.5 kg of total mixed ration in dry matter basis for 4 h) in low or high dose, and was compared to a control meal without compound. Saliva was sampled orally (unstimulated saliva) for physico-chemical composition analysis. Composition of the ingested saliva (stimulated saliva), salivation and feed boli characteristics were assessed from ingesta collected at the cardia during the first 30 min of the meal. Analysis of unstimulated saliva showed that supplementation with capsaicin and thyme oil increased buffer capacity, while supplementation with thymol, L-menthol and gentian root decreased saliva pH. In addition, supplementing angelica root decreased saliva osmolality. Regression analysis on unstimulated saliva showed negative associations between mucins and bicarbonate as well as with phosphate when garlic oil, thyme oil or angelica root was supplemented. Analysis of stimulated saliva demonstrated that supplementation with garlic oil increased phosphate concentration, thyme oil tended to increase osmolality, capsaicin and thymol increased buffer capacity, and ginger increased phosphate content. Furthermore, salivation rate increased with ginger and thymol, and tended to increase with garlic oil, capsaicin, L-menthol and mint oil. Feed ensalivation increased with capsaicin. A positive association was found between feed bolus size and salivation rate when any of the phytogenic compounds was supplemented. Overall, our results demonstrate positive short-term effects of several phytogenic compounds on unstimulated and stimulated saliva physico-chemical properties, salivation or feed boli characteristics. Thus, the phytogenic compounds enhancing salivary physico-chemical composition have the potential to contribute to maintain or improve ruminal health in cattle fed concentrate-rich rations.
唾液有助于饲料摄入和养分循环，是反刍动物重要的pH缓冲剂，对于采食高浓缩日粮、易引发瘤胃酸化的牛来说尤为重要。本试验评估了9种植物源化合物对牛唾液分泌、唾液理化成分以及采食饲料团块特性的短期影响。总共使用了9头安装了瘤胃瘘管的荷斯坦奶牛。每种化合物均以低剂量或高剂量添加到其中4头奶牛的高浓缩日粮（以干物质计2.5千克全混合日粮，持续4小时）中进行测试，并与不添加化合物的对照日粮进行比较。通过口腔采集唾液样本（非刺激性唾液）用于理化成分分析。采食唾液（刺激性唾液）的成分、唾液分泌量和饲料团块特性则根据采食开始后30分钟内在贲门处采集的食糜进行评估。非刺激性唾液分析表明，添加辣椒素和百里香油可提高缓冲能力，而添加百里香酚、L-薄荷醇和龙胆根会降低唾液pH值。此外，添加当归根会降低唾液渗透压。对非刺激性唾液的回归分析表明，添加大蒜油、百里香油或当归根时，粘蛋白与碳酸氢盐以及磷酸盐之间呈负相关。刺激性唾液分析表明，添加大蒜油可提高磷酸盐浓度，百里香油倾向于提高渗透压，辣椒素和百里香酚可提高缓冲能力，生姜可提高磷酸盐含量。此外，生姜和百里香酚可提高唾液分泌率，大蒜油、辣椒素、L-薄荷醇和薄荷油也有提高唾液分泌率的趋势。辣椒素可提高饲料的唾液浸润程度。添加任何一种植物源化合物时，饲料团块大小与唾液分泌率之间均呈正相关。总体而言，我们的结果表明，几种植物源化合物对非刺激性和刺激性唾液的理化性质、唾液分泌或饲料团块特性具有积极的短期影响。因此，能够改善唾液理化成分的植物源化合物有潜力维持或改善采食高浓缩日粮的牛的瘤胃健康。
