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Negli ovini da latte l’ingestione di alimenti contaminati da sostanza indesiderate rappresenta un rischio sia per animali al pascolo che per quelli confinati. L’assunzione di composti tossici negli ovini da latte comporta effetti negativi a carico dell’animale oltre che costituire un potenziale elemento di rischio per il consumatore finale nel caso in cui il composto tossico permanga nel latte o nelle carni. I metalli pesanti, le diossine e le micotossine rappresentano le sostanze indesiderate negli alimenti per animali di maggiore interesse per la filiera di produzione degli ovini da latte. La presenza di residui di contaminanti nel latte ovino e nei derivati caseari costituisce un importante indicatore della igienicità della filiera produttiva e allo stesso tempo è ritenuto un marcatore indiretto della salubrità dell’ambiente di produzione. Questo lavoro riassume gli aspetti di maggiore rilievo circa gli effetti dei metalli pesanti, delle diossine e di alcune micotossine sugli ovini, con particolare riferimento al loro trasferimento nel latte e nei derivati.

Milk production is largely dependent on the shape of the lactation curve. Important elements in the lactation pattern are the peak yield, which is the maximum milk yield during lactation, and lactation persistency, which is the ability of animals to maintain a reasonably constant milk yield after the lactation peak. "Persistent" animals are those with flatter lactation curves. Domesticated animals have lactation curves with high peaks and persistency, and thus higher milk yield than their wild ancestors. Dairy breeds, when compared to meat and wool breeds, have greater persistency rather than high peaks. In dairy sheep, genetic selection has caused deep morphological changes in the udder and physiological changes in the whole body of the animal. The former are seen in the higher mammary cistern volume and the latter in neuro-hormonal changes that allow the alveoli to have a longer life-span and maintain a metabolic status that favors the switch of energy and nutrients to the mammary gland instead of body reserves. In practice, the ideal lactation curve has a reasonably high peak and a flat trend after the peak. More persistent lactation is desirable due to the relationships between this trait and health status and feed costs (Dekkers et al., 1998; Grossman et al., 1999). Animals with very high peak yields are not able to consume adequate amounts of nutrients in the first part of lactation. This causes a negative energy balance, reduced reproductive efficiency and increased susceptibility to diseases (Jakobsen et al., 2002; Swalve, 2000). By contrast, animals with flat curves are less subject to metabolic stress in early lactation and have a more constant pattern of energy requirements throughout lactation. This means that cheaper feeds can be used (Sölkner and Fuchs, 1987; Dekkers et al., 1998). In most cases the milk of the first month of lactation is suckled by the lamb. This means that there is less milk yield data available on the ascending phase of lactation, which consequently has been little studied.

In 90 Sarda dairy ewes the effects of lactation stage, parity, beta-lactoglobulin genotypes, and somatic cell count (SCC) on the milk content of total protein (TP), casein (CN), whey protein (WP) and its fractions alpha-lactalbumin (ALA), beta-lactoglobulin (BLG), serum albumin (SA), immunoglobulin (IG) and lactoferrin (LF) were analysed using a linear mixed model. Mean values of variables (g/l) were: TP (54.0), CN (43.0), WP (11.0), BLG (4.78), ALA (1.37), SA (0.61), IG (3.83) and LF (0.28). The lactation stage significantly affected all the variables analysed. TP, CN and WP concentrations tended to increase throughout lactation, with the increase of WP being more pronounced than the corresponding variation in CN. There was no definite trend in BLG content, whereas ALA concentration decreased as lactation progressed. The parity affected almost all variables studied. WP concentration differed significantly only between the second and fourth parity (10.45 vs 11.44 g/l). BLG and SA concentrations were significantly lower in the youngest ewes. The BLG genotype affected milk yield, but no effects were observed on the components of the milk. The SCC influenced almost all variables studied. The TP concentration was significantly higher in milk with SCC >1,000,000 (55.0 g/l) than in milk with lower SCC (53.4 g/l). This was mainly due to the increase of WP (12.52 and 10.24 g/l in milk with SCC above and below 1,000,000/ml respectively), especially in those WP fractions originating from blood.

Percent trygliceride composition, total carotenoids and chlorophylles and the main quality parameters of 110 extra-virgin oils of the five most important Sardinian production places have been inspected. Statistical analysis of data revealed that some of the above cited components can serve as discriminant factors to exactly define the origin of the oil, while others do not. In particular, it has been found that an exact identification of the place of origin is easily achieved for zones 2 (south Sardinia) and 3 (north-west Sardinia), because they show the significantly highest content of POL triglyceride and palmitoleic acid or SOO triglyceride and stearic acid, respectively. Moreover, zones 2 and 3 have the significant lowest content of OOO and PSO triglycerides, respectively. A cross comparison of parameters allows the place of origin identification for the remaining zones as well. Su 110 oli vergini d'oliva provenienti dalle cinque principali zone olivicole della Sardegna sono stati determinati: composizione percentuale in trigliceridi ed in acidi grassi, contenuto di caroteni e clorofille totali e alcuni parametri primari della qualita. L'elaborazione statistica dei risultati ottenuti ha permesso di individuare la presenza di alcuni componenti, che fungono da discriminanti in funzione della zona di provenienza degli oli. Altri componenti, invece, risultano omogenei tra l'intera produzione sarda. In particolare, si è visto che è possibile discriminare agevolmente gli oli della zona 2 (Sardegna meridionale) e 3 (Sardegna nordoccidentale) perchè presentano il più alto contenuto dal punto di vista statistico (P

Detecting adaptive loci in the genome is essential as it gives the possibility to understand what proportion of a genome or which genes are under the pressure of natural selection. In this paper, we used a Spatial Analysis Method (SAM) recently developed to detect signatures of natural selection in sheep breeds.With the contribution of Geographical Information Systems, environmental variables, and AFLP data, multiple univariate logistic regressions are run to test for association between allelic frequencies at marker loci and environmental variables. The results of the application of this method to sheep breeds are compared with those obtained with a standard population genetics approach.

Recent studies have demonstrated that forage legumes with moderate levels of condensed tannins (CT) can be favourable for animal nutrition. The nutritional benefits included faster growth rates, higher milk production, increased fertility, improved nitrogen (N) utilization and reducing greenhouse gas and N emissions. The main objective of the present thesis was to investigate how CT from legumes, in particular Birdsfoot trefoil (BT) and Sainfoin (SF) can improve protein utilization of ruminant and monogastric and by that improve their performance and the quality of the final product. The effects of CT from BT was first investigated in Chapter 2. In particular, we focused on the potential of CT to reduce the formation of the compounds responsible of the “pastoral flavour” on lamb meat as well as their ability to protect dietary PUFA from ruminal biohydrogenation enhancing their availability in the small intestine. The influence of BT on intake, digestibility and N balance of lambs fed diets differing in CP level was investigated in the Chapter 3. In this study, special emphasis has been given to the fate of CT by monitoring possible changes in CT concentrations as well as soluble, protein and fibre bound CT fractions after the passage through the digestive tract. Finally, in the Chapter 4 we investigated the impact of increasing levels of CT from SF on growth performance, carcass characteristics and meat quality of 48 entire male (EM) with special focus on the potential of CT to reduce the formation of the boar taint related compounds.

In this dissertation we showed the in vitro and in vivo anthelmintic activity of selected plant extracts and secondary metabolites against gastrointestinal nematodes and their effects on Sarda dairy ewes. The first chapter reviewed the effects of gastrointestinal nematodes and lungworms on the health status and welfare of small ruminants and the strategies to control nematode infestations. Moreover, the anthelmintic properties of the plant extracts are illustrated. The second chapter reported the in vitro anthelmintic activity of Ruta chalepensis L. extracts and of selected phytochemicals against gastrointestinal nematodes and lungworms of sheep. Especially, Ruta chalepensis L. methanol extract and 2-undecanone showed the highest nematicidal activity with an EC50/96h= 0.10 mg/mL and EC50/24h= 0.88 mg/mL, respectively. The data revealed in vitro dose-dependent anthelmintic activity. In the third chapter we reported the experiment where increasing doses of furfural and 2-hydroxybenzaldehyde were orally administered to Sarda dairy ewes. These phytochemicals and their metabolites were not detected in milk, urine and faecal samples. Moreover, the ewe blood parameters were within the normal range. In the fourth chapter we reported that a single oral dose of furfural, 2-hydroxybenzaldehyde, 2-undecanone and albendazole was administered in sheep. The compounds and their metabolites were not detected in milk with the exception of albendazole sulfoxide a known metabolite of albendazole. Therefore, no negative effects were observed in animals treated with these compounds. With regard to anthelmintic activity, the furfural, 2-hydroxybenzaldehyde, 2-undecanone groups showed the lowest activity if compared with albendazole. In the future, we will optimise the dosage and the mode of action of furfural, 2-hydroxybenzaldehyde and 2-undecanone.

The availability of data about the fatty acids composition in different tissues of fetus and newborn piglets seems essential for the evaluation of nutrient requirements of gestating/lactating sows. In newborn un-suckling piglets data analyzed show strong heterogeneity among different tissues, especially for fatty acids (FA) synthesized ex novo like long chain polyunsaturated fatty acids (PUFA). Fatty acid profile in suckling animals are different between tissues, indicating that the growth of each organ or tissues in body of newborn piglets follows a different route and therefore requires distinct combination of fatty acids. In tissues there are a strong relationship between the concentration of LCPUFA (long chain polyunsaturated fatty acids) and their precursors that are the essential fatty acids C18:2 n-6 and C18:3 n-3. This indicate that, during the suckling time, piglet metabolism plays a key role in the utilization of milk substrates, also in terms of ex novo synthesis of fatty acids. Comparison of fatty acids profile of plasma from sows and their suckling piglets. are strongly differed. The concentration of FA in swine plasma was markedly influenced by lipid composition of the diet. In plasma of piglets there are some FA, like LCPUFA which are not detected in plasma of their mothers. Finally, Pearson correlation analysis of the fatty acids concentrations evidenced interesting relationship between them.