Department of Agronomy and Natural Resources, Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel.
J Chem Ecol. 2010 Jul;36(7):736-43. doi: 10.1007/s10886-010-9809-z. Epub 2010 Jun 18.
We investigated whether Mediterranean goats use salivary tannin-binding proteins to cope with tannin-rich forages by determining the affinity of salivary or parotid gland proteins for tannic acid or quebracho tannin. Mixed saliva, sampled from the oral cavity, or parotid gland contents were compared to the intermediate affinity protein bovine serum albumin with a competitive binding assay. Goats that consume tannin-rich browse (Damascus) and goats that tend to avoid tannins (Mamber) were sequentially fed high (Pistacia lentiscus L.), low (vetch hay), or zero (wheat hay) tannin forages. Affinity of salivary proteins for tannins did not differ between goat breeds and did not respond to presence or absence of tannins in the diet. Proteins in mixed saliva had slightly higher affinity for tannins than those in parotid saliva, but neither source contained proteins with higher affinity for tannins than bovine serum albumin. Similarly, 3 months of browsing in a tannin-rich environment had little effect on the affinity of salivary proteins for tannin in adult goats of either breed. We sampled mixed saliva from young kids before they consumed forage and after 3 months of foraging in a tannin-rich environment. Before foraging, the saliva of Mamber kids had higher affinity for tannic acid (but not quebracho tannin) than the saliva of Damascus kids, but there was no difference after 3 months of exposure to tannin-rich browse, and the affinity of the proteins was always similar to the affinity of bovine serum albumin. Our results suggest there is not a major role for salivary tannin-binding proteins in goats. Different tendencies of goat breeds to consume tannin-rich browse does not appear be related to differences in salivary tannin-binding proteins.
我们通过测定唾液或腮腺蛋白对单宁酸或奎纳克单宁的亲和力，来研究地中海山羊是否通过唾液单宁结合蛋白来应对富含单宁的饲料。通过竞争性结合测定法，将从口腔中采集的混合唾液或腮腺分泌物与中等亲和力的蛋白牛血清白蛋白进行比较。依次给食用富含单宁的饲料（大马士革）和倾向于避免单宁的饲料（曼贝尔）的山羊喂食高（黄连木）、低（野豌豆干草）或零（小麦干草）单宁饲料。唾液蛋白与单宁的亲和力在山羊品种之间没有差异，也不受饮食中是否存在单宁的影响。混合唾液中的蛋白对单宁的亲和力略高于腮腺唾液中的蛋白，但这两种来源的蛋白对单宁的亲和力都不如牛血清白蛋白高。同样，在富含单宁的环境中觅食 3 个月，对两种品种成年山羊唾液蛋白对单宁的亲和力影响不大。我们从小山羊采食饲料前和在富含单宁的环境中觅食 3 个月后采集混合唾液。在觅食之前，曼贝尔幼崽的唾液对单宁酸（但不是奎纳克单宁）的亲和力高于大马士革幼崽的唾液，但在暴露于富含单宁的饲料 3 个月后，没有差异，并且蛋白的亲和力始终与牛血清白蛋白的亲和力相似。我们的研究结果表明，唾液单宁结合蛋白在山羊中没有主要作用。不同品种的山羊对富含单宁的饲料的食用倾向似乎与唾液单宁结合蛋白的差异无关。
