Vastolo, Alessandro (2022) Valorisation of agro-industrial residues in animal nutrition, a sustainable approach. [Tesi di dottorato]

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Tipologia del documento:	Tesi di dottorato
Lingua:	English
Titolo:	Valorisation of agro-industrial residues in animal nutrition, a sustainable approach
Autori:	Autore Email Vastolo, Alessandro alessandro.vastolo@unina.it
Data:	10 Marzo 2022
Numero di pagine:	192
Istituzione:	Università degli Studi di Napoli Federico II
Dipartimento:	Medicina Veterinaria e Produzioni Animali
Dottorato:	Scienze veterinarie
Ciclo di dottorato:	34
Coordinatore del Corso di dottorato:	nome email Cringoli, Giuseppe cringoli@unina.it
Tutor:	nome email Cutrignelli, Monica Isabella [non definito]
Data:	10 Marzo 2022
Numero di pagine:	192
Parole chiave:	by-products, animal nutrition, circular economy, feedstuff, citrus pulp, hemp
Settori scientifico-disciplinari del MIUR:	Area 07 - Scienze agrarie e veterinarie > AGR/18 - Nutrizione e alimentazione animale
Depositato il:	22 Mar 2022 09:08
Ultima modifica:	28 Feb 2024 10:34
URI:	http://www.fedoa.unina.it/id/eprint/14481

Abstract

Using agricultural and industrial residues is an established practice to feed animals, limiting farming costs, and reduce waste. However, by-products showed a heterogeneous chemical composition, strict seasonality, and short shelf life. Consequently, diets supplementation with by-products can be ineffective if not harmful for animal production and health. The doctoral project aimed to evaluate the chemical and nutritional characteristics of some by-products of the Mediterranean area. In vivo and in vitro studies were carried out to identify the correct use of by-products in animal nutrition. In particular, the thesis contains five manuscripts published in international journals, a general introduction, a discussion, and conclusion chapter. In this regard, chapter two presents an extensive review of the scientific literature published in the last decade. In chapters three, four, and five in vitro technique of cumulative gas production (IVGPT) has been used to evaluate the fermentation characteristics of some by-products derived from fruit processing, olive, and hemp oil production. The first study was carried out using the caecal content of pigs as inoculum highlighting how the by-products of citrus fruit processing (pulps and molasses) can be applied as energy sources in every phase of swine rearing. Indeed, these kinds of by-products are rich in fermentable carbohydrates, which are useful for pig health, despite inhomogeneity of chemical composition. Although this olive pomace has a high content of lipids and energy, it is difficult to use due to the high lignin content that limits its digestibility. However, it could be used only in the fattening phase when energy requirements and digestive utilization are high. The fermentable ingredients' short shelf-life issue, such as by-products of prickly pears’ processing, was addressed in chapter four. The ensiling of biomass with the addition of wheat straw in the ratio of five percent allows preserving the substrate's fermentable carbohydrates using bovine rumen fluid as inoculum. However, further investigations must be carried out in vivo to evaluate other aspects, such as the palatability and the effects of the antioxidant molecules on milk yield and quality. The chemical and nutritional characteristics of hemp (Cannabis sativa L.) processing residues have been assessed in the last two studies. This herbaceous crop was abandoned for years mainly due to the equivocal confusion with Cannabis indica L., which is rich in tetrahydrocannabinol (Δ9-THC) with psychoactive action. This plant has been returned to arousing interest throughout Europe in the last decade. In this regard, several aspects, such as agronomic advantages and the potential innovative uses of biomass, would be at the basis of the newfound interest in the cultivation of hemp. In particular, hemp oil and flour, being rich in polyunsaturated fatty acids and bioactive molecules, could have beneficial effects on human health. A primary investigation revealed the extreme heterogeneity of the residues from the cultivation and processing of hemp seeds and inflorescences in terms of lipid content and structural carbohydrates. Moreover, all substrates showed quite significant levels of protein and crude ash. Therefore, the fermentation characteristics of the most fibrous by-products have been evaluated in vitro with ruminal buffalo fluid (chapter 5). Whilst, the effects of hempseed cake supplementation, being rich in polyunsaturated fatty acids, were tested in healthy adult dogs (chapter 6). The study regarding hempseed by-products’ fermentation characteristics showed that residues of oil and flour have an interesting chemical composition. Furthermore, the limited digestibility and the low gas production of hemp inflorescence by-products indicated these substrates are a little used by ruminal microorganisms. These results could be due to the high content of lignified structural carbohydrates and phytocannabinoids, which are little used by ruminal microorganisms. The poor methane production resulting in fermentation of these by-products would suggest that they could have the potential to limit the greenhouse emissions in ruminant farms. The last study was carried out on healthy adult dogs, comparing the effects of commercial diet supplementation with two different lipid sources (tallow vs. hempseed cake). Significant improvements in some biochemical parameters, such as cholesterol levels and some markers of renal and hepatic function, were observed when dogs feed a diet supplemented with hempseed cake. These effects would be mainly attributable to the high levels of polyunsaturated fatty acids of the hempseed cake, while further investigations are needed to establish the possible role played by the bioactive molecules contained therein. However, it should be noted that the fatty acidic profile of the diet containing hempseed cake has negatively affected the peroxidation index of the diet, so before industrial use, it will be necessary to evaluate the strategies to preserve the feed thus integrate from the risk of oxidation

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