Research Title
"EVOLUTION OF CONDENSED TANNINS CONTENT IN WILD LEGUMINOUS SPECIES
AND FORAGE CHICORY AND RELATED EFFECTS ON ANIMALS."

Research Unit SASSARI - ISPAAM-CNR
Via Enrico de Nicola, 07100 Sassari
Tel 079 229332 - Fax 079 229354
Responsabile del progetto Dr. Simonetta Bullitta - bullitta@cspm.ss.cnr.it
Collaboratori: Dr.ssa G. Piluzza, S. Nieddu, P. Saba, D. Dettori, T. Stangoni, dr. G. Sulas.

Italian version
 

Condensed tannins (CT)

polyphenolic secondary compounds;

 

capable to react by hydrogen bounding with plant proteins to form CT-protein complexes stable and insoluble at pH 3.5-7.0;

 

dissociating at pH<3.5 with protein release.

 

CT containing species do not cause bloat in ruminants;

 

moderate CT concentrations in forages (up to 5% DM) could enhance forage nutritive value by reducing protein degradation from rumen bacteria;

 

increasing amino acid supply for adsorption in the small intestine of ruminants.

 

CT accumulate differentially in life cycle stages and organs of plants    their structure is related to their biological activity

 

CT content is also related to enviromental factors.

 

In addition CT are also considered a defense against plant predators. Some plants have evolved CT production as a defence strategy, against invasion by pathogenic bacteria and fungi, and against being eaten by insects and herbivores.

 

  

OBJECTIVES

Determination of CT accumulation during the different phenological phases of pasture species whose CT content was not completely or never determined before, identify species and select new varieties suitable for grazing from natural populations of pasture species.

 

Determine CT effects on grazing animals.

 

Establish most appropriate forage utilization techniques to enhance CT effects on grazing animals.

 

Quantification of total phenolics in plant tissues for their biological role as secondary metabolites for their presumed ecological importance in plant-animal interactions.

 

EVOLUTION OF CT CONTENT IN WILD SPECIES FROM MEDITERRANEAN PASTURES

With the aim to study the variability in the CT accumulation in different plant components (leaves, stems, flowers) in the plant life cycle, tissue samples were made at different phenological phases from the following species:

 

 

 Hedysarum coronarium
(Foto ISPAAM sez. SS)		 Hedysarum spinosissimum
(Foto ISPAAM sez. SS)		 Hedysarum glomeratum
 (Foto ISPAAM sez. SS)
Lotus ornithopodiodes
(Foto ISPAAM sez. SS)		 Lotus cytisoides
(Foto ISPAAM sez. SS)		 Lotus edulis
 (Foto ISPAAM sez. SS)


Onobrychis viciifolia
(Foto ISPAAM sez. SS)
  Cichorium intybus
 (Foto ISPAAM sez. SS)

 

CT content determination was made by the colorimetric assay Butanol-HCl-Fe 3+

Delphinidin was used as standard, according to the results of CT chemical structure analysis of various species done by the research unit in Lodi.

Total phenolics and tannin phenolics content was also determined by Folin Ciocalteau method, tannic acid was used as standard.

CT VARIATION FOLLOWING PARASITE ATTACKS

Species under trial in the field, were monitored for pathogen attacks. Plant tissues infected by pathogens were analysed in order to assess the CT, Total phenolics and Tannin phenolics content changes following the infection.


EVALUATION OF CT CONTENT VARIATION IN LOCAL POPULATIONS OF H.coronarium GRAZED BY LAMBS AND STUDY OF CT EFFECTS ON GRAZING ANIMALS.

 
Tissue samples were made on local H. coronarium natural populations grazed by lambs, in order to evaluate CT content variation on grazed plants. Moreover, CT effects on lambs growth and health were checked by recording weight increases of lambs and by collecting blood samples to determine metabolic profiles and plasmatic redox states on two groups of animals (PEG and no PEG supplied) in collaboration with Napoli 1 Research Unit.

 

 

COLLABORATIONS

ISCF Lodi (Chemical analysis to identify CT and total phenols; isolation of purified CT and phenols extracts from Sardinian local populations of wild species from pastures)

 

ISPAAM Napoli 1 and IZCS Bonassai (Evaluation of effects on grazing lambs of CT from Sardinian H. coronarium local germplasm)

 

ISPAAM Napoli 2 and ISPAAM Napoli 3 (Effects of CT and phenols extracts from Sardinian local populations of wild species from pastures on the growth of ruminal bacteria Ruminococcus albus, and of some strains of lactic bacteria: Lactobacillus delbrueckii (subsp. Bulgaricus), Lactobacillus plantarum, Streptococcus thermophilus)

 

ACEP Palermo (Experimental data comparison)