Introduzione in coltura di nuove specie foraggere: produttività e composizione bromatologica di <i>Chrysanthemum coronarium</i> L. (crisantemo) sottoposto a pascolamento simulato

Crysanthemum coronarium L. is a weed of grain cereals also grazed by sheep. A research, aimed at the productive and qualitative characterization of C. coronarium, was carried out in North Sardinia (Italy) during 1993-96 in order to evaluate its introduction and role, as pasture species, within forage systems for dairy ewes. A sowed sward of C. coronarium has been evaluated both according to the «Corrall» method, with cutting every 28 days, and under undisturbated herbage accumulation. “Corrall” seasonal yield trends were different between years due to the meteorological conditions and number of cuts. The forage yields were 3,5, 2,5 e 1,9 t ha-1 ( respectively in the three years with high dry matter availability in winter and favourable crude protein and NDF contents, particularly in late spring. Under undisturbated accumulation forage production were from twice to six times higher than those obtained using the “Corrall” method. First data about seed production and re-establishment have shown the self-reseeding capacity of this species. On the basis of the results obtained, C. coronarium appears very interesting as forage species and its introduction in forage chains is desiderable. Chrysanthemum coronarium L. (crisantemo) è una composita diffusa negli incolti ed infestante di colture a ciclo autunno-vernino che, sulla base di numerose osservazioni, è appetita dagli ovini. Al fine di valutare il suo possibile inserimento e ruolo, come specie da pascolo, all'interno di sistemi foraggeri asciutti mediterranei è stata effettuata una ricerca volta alla caratterizzazione produttiva e qualitativa di una popolazione naturale di crisantemo. Nel Nord-Sardegna una cotica artificiale di C. coronarium è stata valutata sia secondo la metodologia “Corrall”, con sfalci ripetuti ogni 28 giorni, sia sotto accrescimento indisturbato, durante il triennio 1993-96. Le curve stagionali di produzione relative alle tre annate sono risultate diverse tra loro per effetto dell'andamento meteorologico e della frequenza degli sfalci. Le produzioni complessive accertate con la prima metodologia sono state pari a 3,5, 2,5 e 1,9 t ha-1 di sostanza secca rispettivamente nelle tre annate, con elevate disponibilità invernali e favorevoli tenori in proteina grezza e NDF soprattutto nelle utilizzazioni di tarda primavera. Le produzione massime conseguite sotto accrescimento indisturbato sono risultate pari a 8,8, 10 e 12 t ha-1 nelle tre annate e da 2 a 6 volte superiori rispetto a quelle stimate con la metodologia “Corrall”. I primi dati sulla produzione degli acheni ed il reinsediamento spontaneo delle plantule nell'autunno successivo hanno messo in evidenza la spiccata capacità autoriseminante del crisantemo. Sulla base delle caratteristiche produttive e qualitative riscontrate nel triennio, C. coronarium appare di sicuro interesse dal punto di vista foraggero; pertanto è auspicabile la sua introduzione in coltura ed il suo inserimento come specie da pascolo in sistemi foraggeri asciutti

Quantificazione dell'azotofissazione della sulla in Sardegna: azoto fissato nella fitomassa epigea ed effetto dell'inoculazione

An important and economic source of nitrogen for Mediterranean crop and forage systems arises from symbiotic nitrogen fixation, which contributes also to a high environmental protection and sustainability. This papers refers on the quantification of nitrogen fixation in sweetvetch, by the isotopic dilution and nitrogen balance methods. In addition, the effect of sweetvetch inoculation with a Sardinian strain of Rhizobium sullae was evaluated against an uninoculated treatment. The potential of nitrogen fixation in sweetvetch, estimated by the isotopic dilution method, resulted high, reaching 180 kg ha-1 of nitrogen fixed in the biennium. The nitrogen balance method underestimated the nitrogen fixation compared to the isotopic dilution. Very low differences between inoculated and uninoculated sweetvetch were due to a presence of resident rhizobia in the soil. This result outlines the need of evaluating where inoculation is necessary or useless

Cytokeratin-19 positivity is acquired along cancer progression and does not predict cell origin in rat hepatocarcinogenesis

Although the expression of the stem/progenitor cell marker cytokeratin-19 (CK-19) has been associated with the worst clinical prognosis among all HCC subclasses, it is yet unknown whether its presence in HCC is the result of clonal expansion of hepatic progenitor cells (HPCs) or of de-differentiation of mature hepatocytes towards a progenitor-like cell phenotype. We addressed this question by using two rat models of hepatocarcinogenesis: the Resistant-Hepatocyte (R-H) and the Choline-methionine deficient (CMD) models. Our data indicate that the expression of CK-19 is not the result of a clonal expansion of HPCs (oval cells in rodents), but rather of a further step of preneoplastic hepatocytes towards a less differentiated phenotype and a more aggressive behavior. Indeed, although HCCs were positive for CK-19, very early preneoplastic foci (EPFs) were completely negative for this marker. While a few weeks later the vast majority of preneoplastic nodules remained CK-19 negative, a minority became positive, suggesting that CK-19 expression is the result of de-differentiation of a subset of EPFs, rather than a marker of stem/progenitor cells. Moreover, the gene expression profile of CK-19-negative EPFs clustered together with CK-19-positive nodules, but was clearly distinct from CK-19 negative nodules and oval cells. Conclusion: i) CK-19-positive cells are not involved in the early clonal expansion observed in rat hepatocarcinogenesis; ii) CK-19 expression arises in preneoplastic hepatocyte lesions undergoing malignant transformation; iii) CK-19 positivity in HCCs does not necessarily reflect the cell of origin of the tumor, but rather the plasticity of preneoplastic cells during the tumorigenic proces

LCA study of oleaginous bioenergy chains in a Mediterranean environment

This paper reports outcomes of life cycle assessments (LCAs) of three different oleaginous bioenergy chains (oilseed rape, Ethiopian mustard and cardoon) under Southern Europe conditions. Accurate data on field practices previously collected during a three-year study at two sites were used. The vegetable oil produced by oleaginous seeds was used for power generation in medium-speed diesel engines while the crop residues were used in steam power plants. For each bioenergy chain, the environmental impact related to cultivation, transportation of agricultural products and industrial conversion for power generation was evaluated by calculating cumulative energy demand, acidification potential and global warming potential. For all three bioenergy chains, the results of the LCA study show a considerable saving of primary energy (from 70 to 86 GJ·ha−1) and greenhouse gas emissions (from 4.1 to 5.2 t CO2·ha−1) in comparison to power generation from fossil fuels, although the acidification potential of these bioenergy chains may be twice that of conventional power generation. In addition, the study highlights that land use changes due to the cultivation of the abovementioned crops reduce soil organic content and therefore worsen and increase greenhouse gas emissions for all three bioenergy chains. The study also demonstrates that the exploitation of crop residues for energy production greatly contributes to managing environmental impact of the three bioenergy chains

Leguminose da pascolo di seconda generazione: una opportunità per i sistemi foraggero-zootecnici mediterranei?

Nell’ultima decade, diverse varietà di leguminose da pascolo di seconda generazione (Loi et al., 2005) selezionate in Australia vengono distribuite nel mercato sementiero europeo, ampliando di fatto la possibilità di scelta dei nostri agricoltori (Sulas, 2005; Porqueddu &amp; González, 2006). Pertanto, è importante valutare i benefici derivanti dalla loro introduzione in sistemi foraggero-zootecnici mediterranei. In questo lavoro condotto in Sardegna si riferisce sull’adattamento e la persistenza di alcune leguminose di seconda generazione

Validità agronotnica e sostenibilità di un pascolo migliorato con specie autoriseminanti in alternativa all'erbaio autunno-vernino nei sistemi foraggeri asciutti mediterranei

The results of a three year trial run in Sardinia within a larger experiment on rainfed forage systems for dairy sheep are reported. The agronomic, zootechnic and economic validity of an improved pasture (sod seeding of Lolium rigidum ecotype «Nurra» and Trifolium brachycalycinum «Clare») as an alternative to the grazing of short term forage crops (oats) were evaluated. The forage production and consumption of the improved pasture were higher than those of the oats in two years out of three and on average in the three years. The seasonal distribution of the forage production was better in the improved pasture for the quicker establishment in Autumn. The sowing date of the oats was delayed in the second year because of the abundant and frequent rainfall in the early Autumn. The subclover showed a slow establishment and was less competitive than annual ryegrass in the first year. Its self-reseeding was affected by the damage of Bruchidius trifolii. Annual ryegrass gradually established a thick and persistent sward through a seed yield over than 50000 seeds m-2. The milk yield of ewes grazing the improved pasture resulted 20% higher than that of the ewes grazing oats. The average annual costs ofthe oats were about two times higher and the agronomie and zootechnic results lower than those of the improved pasture. Taking into account the environmental aspects (soil protection from erosion in the Autumn) and the management aspects, it was concluded that the self-reseeding improved pasture is an effective alternative to short term forage crops in the dairy sheep forage farming systems of the Mediterranean environment. Vengono riportati i risultati di una prova triennale svolta in Sardegna nell'ambito di un confronto tra sistemi foraggeri asciutti per ovini da latte. E’ stata valutata la validità in termini agronomici, zootecnici ed economici di un pascolo migliorato con la semina su sodo di un miscuglio di Lolium rigidum ecotipo «Nurra» e Trifolium brachycalycinum «Clare» come possibile soluzione alternativa al pascolamento degli erbai di cereali autunno vernini. La disponibilità foraggera e i consumi alimentari rilevati sul pascolo migliorato sono risultati superiori a quelli dell'erbaio in due annate su tre e nella media del triennio. La distribuzione stagionale della produzione è risultata più favorevole nel pascolo migliorato per il più rapido reinsediamento in autunno. L'epoca di semina dell'erbaio nella seconda annata è stata ritardata per le abbondanti e frequenti precipitazioni autunnali che hanno impedito la preparazione del letto di semina. Il trifoglio brachicalicino ha mostrato un più lento insediamento e minore competitività rispetto al loglio rigido, e la risemina naturale è stata fortemente limitata dall'attacco di un coleottero (Bruchidius trifolii). Il loglio rigido ha invece progressivamente costituito un cotico fitto e persistente, attraverso produzioni di seme sempre superiori a 50000 semi m-2. Le produzioni di latte ottenute sul pascolo migliorato sono risultate mediamente superiori del 20% rispetto a quelle ottenute con il pascolamento dell'avena. I costi colturali medi annui dell’erbaio sono risultati circa doppi rispetto a quelli del pascolo migliorato, e i risultati agronomici e zootecnici nettamente inferiori. E’ stato concluso che il pascolo migliorato con autori seminanti costituisce un'efficace alternativa al pascolamento degli erbai di cereali nei sistemi foraggeri per ovini da latte in ambiente mediterraneo, in linea con l'esigenza di tutela ambientale (protezione del suolo dall'erosione in autunno)

Stima dei surplus di macronutrienti attraverso il metodo del bilancio apparente in sistemi foraggero-zootecnici ovini sardi

A farm survay with the aim to estimate the nitrogen, phosphorus and potash apparent bai ance using the methodology proposed by Simon and Le Corre (1992) was carried out during 1993-1994 on 20 dairy sheep farms, representative of the farming systems widespread in the Sardinian N-W lowland. The macronutrient inputs and outputs data elaboration at farm scale, the physical-chemical analysis on the soil characteristic of the area and the critical investigation of the crop and livestock practices applied, it has allowed to clarify the source of surplus generation. High variability in the ratio of the crops among farms, agronomic techniques, stockmg rate, crop and animal performances was observed. Average annual surplus, calculated as difference between inputs and outputs, were 67,53,8 and 1,7 kg ha-1 for N, P2O5 e K2O respectively. The efficiency for N and P2O5 use was low: 16,7 and 8,3% respectively while high for K2O reaching 82%. Nutrient surplus in the surveyed dairy sheep farms are lower than that observed for other farming systems and/or regions and are related with mineral fertilizer applications. Therefore it is possible to reduce the surplus rationalizing fertilizer applications because of the sufficient content of nitrogen and phosphorus in several farm locations. The apparent balance method represents a useful tool to investigate the agronomic techniques used at farm scale however it presents some semplifications by a scientific point of view. This methodology could permit the valorization of the information collected by the agriculture extension service, helping the technicians to identify a correct farming system management. Su un campione di 20 aziende ovine da latte, rappresentativo della pianura nord-occidentale sarda, è stata condotta nel corso dell'annata 1993-94 un'indagine al fine di stimare i bilanci apparenti di azoto, fosforo e potassio secondo la metodologia proposta da Simon e Le Corre (1992). L'elaborazione dei dati relativi ai flussi di macronutrimenti in entrata ed uscita dall'azienda, l'analisi delle caratteristiche fisico chimiche dei terreni su cui ricadono le aziende censite e l'esame critico delle pratiche colturali e zootecniche rilevate, ha consentito di chiarire attraverso quali meccanismi si generano i surplus degli elementi indagati. E’ stata registrata un'ampia variabilità, nei rapporti fra le diverse colture all'interno delle aziende, delle tecniche agronomiche applicate, del carico mantenuto e dei livelli produttivi delle colture e degli animali. Dal bilancio tra input ed output aziendali è risultato un surplus medio annuo di 67 kg ha-1 per l'N, 53,8 kg ha-1 per la P2O5 e 1,7 kg ha-1 per il K2O. Il valore dell'efficienza d'uso per l'N e la P2O5 è risultato modesto e rispettivamente pari al 16,7 e 8,3% al contrario del K2O che ha fatto registrare l'82%. Le eccedenze di azoto e fosforo osservate nelle aziende in esame si situano su valori medio-bassi quando confrontate con quelle registrate per altre tipologie e/o per altre regioni e risultano correlate alle relative voci in ingresso sotto forma di concimi minerali. Le buone dotazioni dei terreni per i suddetti nutrienti in numerose situazioni aziendali fanno pensare che sia possibile ridurre i surplus razionalizzando le concimazioni. Nel complesso, il metodo del bilancio apparente, pur soggetto ad alcune semplificazioni dal punto di vista prettamente scientifico, si è dimostrato uno strumento utile nell'approfondimento dello studio delle tecniche agronomiche adottate a livello aziendale. Il metodo può consentire la valorizzazione delle informazioni raccolte dai tecnici appartenenti agli enti territoriali di assistenza in agricoltura, agevolandoli nell'individuazione di eventuali in efficienze del sistema foraggero-zootecnico e di scelte agro-ambientali alternative

Growth performances of suckling Sarda breed piglets

Postnatal growth performance has an important economic relevance in pigs breeding. A lot of different factors affect piglets growth rate: prenatal condition, maternal nutritional and hormonal status, breed, litter size; birth weight. Heavier piglets will have more appetite, will react better when turned away from their mother, will grow more and better and will have less health problems and better feed conversion index. The Sarda swine breed has been officially recognized in June 2006, when it has been inserted among the Italian local pig breeds.Our study has focused on various aspects of growth performance of suckling Sarda piglets: how litter size and farm can affect birth weight and growth rate and how sows diet can affect offspring performance. We have also investigated different mathematical models in order to identify which best describe the growth Sarda breed suckling piglets. Piglets ADG was significantly affected by litter size. Contrariwise the effect of and sex was not significant. Furthermore supplemental energy during lactation improved suckling piglets growth rates and consequently reduced the time to reach the slaughter or weaning weight. The Logistic model appears to be a good device to design Sarda purebreed. Due to the dimension of the sample more research must be carried out to evaluate the effect of genetics and environmental conditions on piglets growth. Particular attention must be used to farm system considering peculiarity of the breed, in order to make the farming of Sarda breed economically sustainable

Geoarchaeology of urban space in tropical island environments : Songo Mnara, Tanzania

Past urban settlements in tropical island environments offer particularly challenging sites for mainstream archaeology. Often associated with shallow stratigraphic sequences, archaeological sediments and soils in these sites are strongly influenced by local geology and seawater. This study discusses the advantages and challenges of developing an integrated geoarchaeological programme to examine the use of space at the Swahili stonetown of Songo Mnara Island, Tanzania. This exceptionally well preserved site, occupied for less than two centuries (C14th-16th AD), comprises a complex urban layout with stone built houses, wattle-and-daub structures, funerary complexes, activity areas such as wells, and open areas. The programme has combined geoarchaeological (soil macro-and micromorphology, ICP-AES, pH, EC), geophysical (magnetic susceptibility) and archaeological (large excavations, test trenches, artefact distribution mapping) techniques to investigate the use of space across different contexts. Initial geoarchaeological prospection and opportunistic soil sampling have allowed framing of the island's environmental settings and archaeological deposits as well as outlining open spaces in between buildings. Subsequent research applied a systematic sampling strategy to map geochemical and artefact distributions in conjunction with context-specific soil micromorphology. The results provide a means to map out the impact of occupation across the site as well as to differentiate between open, roofed and unroofed spaces. ICP-AES results, for example, demonstrate that measurements of Ca, Mg, P, S and Sr levels can help discriminate occupation/activity areas in tropical island environments. They also indicate that the depletion of certain elements (e.g. Na, K, and Ni) should be considered as a means of differentiating between roofed and unroofed spaces. The combination of different methodologies demonstrates the importance of addressing discrepancies as well as correlations between multiple datasets for deciphering features within urban spaces in tropical environments and interpreting ancient activities that occurred within them.</p