Tannins in Ruminant Nutrition: Impact on Animal Performance and Quality of Edible Products

Tannins are widespread throughout the plant kingdom, occurring as hydrolysable and condensed tannins and at different levels in several animal feeding sources. Recent years have seen an increasing interest in the use of tannin-rich plants and plant extracts in ruminant diets for improving the quality of their edible products. Some results show that this strategy is effective in improving the fatty acid profile of meat and milk, increasing the level of health-beneficial fatty acids as well as enhancing the oxidative stability of the products. However, the use of tannin-rich feed in animal diets requires great care, due to its possible detrimental effects on animal performance and induction of metabolic disorders. Although promising, the results of studies on the effects of tannins on animal performance and quality of their products are still controversial, probably depending on type and chemical structure of tannins, amount ingested, composition of diet, and species of animal. In this chapter, the current knowledge regarding the effect of dietary tannins on animal performance and the quality of their products (meat and milk), particularly on the fatty acid profile, oxidative stability, and organoleptic properties, is reviewed. The tannin chemistry diversity and its occurrence in ruminant diets, as well as its beneficial and adverse effects on ruminants, will be briefly reviewed, and aspects related to oral cavity physiology, saliva production/composition, and postingestive effects will also be discussed.

Computerized key to the genus Bursaphelenchus Fuchs, analysis of species clusters based on morphology, using information of insect vectors and associated plants, with a revision of the genus.

The genus Bursaphelenchus includes B. xylophilus (Steiner et Buhrer, 1934) Nickle, 1981, which is of world economic and quarantine importance. Distinction among several species of the pinewood nematodes species complex (PWNSC) is often difficult. Besides standard morphology, morphometrics and molecular biology, new tools are welcome to better understand this group. The computerized (or e-) key of this genus, presented in this communication, includes 74 species (complete list of valid species of the world fauna) and 35 characters, that were used by the taxonomic experts of this group, in the original descriptions. Morphology of sex organs (male spicules and female vulval region) was digitized and classified to distinguish alternative types. Several qualitative characters with overlapping character states (expressions) were transformed into the morphometric indices with the discontinuous ranges (characters of ratios of the spicule dimensions). Characters and their states (expressions) were illustrated in detail and supplied by brief user-friendly comments. E-key was created in the BIKEY identification system (Dianov & Lobanov, 1996-2004). The system has built-algorithm ranging characters depending on their diagnostic values at each step of identification. Matrix of species and the character states (structural part of the e-key database) may be easily transformed using statistical packages into the dendrograms of general phenetic similarities (UPGMA, standard distance: mean character difference). It may be useful in the detailed analysis of taxonomy and evolution of the genus and in its splitting to the species groups based on morphology. The verification of the dendrogram using the information on the species links with insect vectors and their associated plants, provided an opportunity to recognize the five clusters (xylophilus, hunti, eremus sensu stricto, tusciae and piniperdae sensu stricto), which seem to be the natural species groups. The hypothesis about the origin and the first stages of the genus evolution is proposed. A general review of the genus Bursaphelenchus is presented.