Cinta Senese pig breed: protein requirements in post-weaning and characterization of two processed pork products enhanced through the addition of omega-3 and natural antioxidants

The thesis approached two main issues of Cinta Senese pork chain, the scarce knowledge on nutritional requirements during the growing phase and the changing demand for healthier pork products. Cinta Senese, as most of the local pig breeds, belongs to the obese pig genotype that have specific metabolic features and, consequently, specific nutritional requirements, markedly different from cosmopolite breeds’ ones. However, Cinta Senese is bred by a small number of farmers and few studies, especially on its nutritional requirements, were carried out. The lack of research leads to unbalanced feeding formulations along the whole life cycle. The first part of the present work was aimed to identify the optimal protein supply for Cinta Senese growing pigs, also considering that during the growing and early fattening stages, pasture supplementation with concentrate is widely applied. Identifying the optimal protein requirements of Cinta Senese growing pigs is of central importance to avoid economic losses, as well as to lower the environmental impact of this rearing system. Maintaining unchanged the quality of protein provided, four protein levels were tested: 12, 14, 16 and 18% of crude protein. The first trial (Trial 1) presented in this thesis concerned the evaluation of the experimental diets in terms of in vivo performances, slaughtering traits and nitrogen balance. The results obtained have indicated the 12% CP diet as adequate to fulfil protein requirements during the growing phase. These results corroborated earlier studies on Cinta Senese regarding different growth stages, but they also agree with most of the studies on other European local pig breeds, that showed similar protein requirements. The second trial (Trial 2) dealt with the improvement of Cinta Senese meat and meat products. These are considered niche products, being spread almost exclusively within II the territory in which this breed is traditionally reared and, due to the peculiarities of its rearing systems, they are also averagely expansive. Moreover, fresh meat market is currently poorly developed. Indeed, Cinta Senese, as all obese genotypes, is characterized by a great predisposition to deposit fat instead of lean tissues, leading to a carcass noticeably fat. These factors contribute to diminish the appeal of fresh meat, that is considered unhealthy due to its fatness. This second part of the work investigated the feasibility of introducing some innovative ingredients in two Cinta Senese pork products, the burger and a type of dry-fermented sausage. Burgers were chosen being considered a wide-appreciated and easy-to-cook fresh product. The novelty proposed was aimed to enhance the fatty acid profile by the addition of EPA and DHA, two essential omega-3 polyunsaturated fatty acids. The enrichment was carried out testing two different techniques: i) adding directly the deodorized fish oil or ii) adding the fish oil previously microencapsulated by spry-drying. The latter technique resulted the most appropriate to preserve the added omega-3 from lipid oxidation during storage and cooking, as well as to avoid extraneous flavors in the final product. Addressing the increasing concerns on the employment of nitrite and nitrate as curing agent in processed products, two different mixture of natural antioxidants were tested in the dry-fermented sausages as sodium nitrite replacement. The vegetal extracts were obtained by olive pomace, grape seed and chestnut. The physical, chemical and sensorial characteristics of the novel products were studied, as well as their aromatic profile. The results obtained suggested that sodium nitrite replacement is practicable, indeed, no differences in microbiological safety, lipid oxidation and aromatic profile were observed. Though, the replacement had some negative effects on instrumental color, being nitrite pivotal in developing the typical redness of processed pork products. In conclusion, Cinta Senese rearing system, as many of Mediterranean silvo-pastoral systems, already presents a plenty of characteristics that perfectly matche with the novel societal demand for animal welfare, return to traditional rearing techniques and genuine products. In this perspective, the local pork chains still have a great untapped potential. Increasing the knowledge about all their parts (rearing, feeding and processing), would help stakeholders to make the whole production chain also economic affordable and environmental respectful.