The olive oil industry, recognised for its beneficial products for health and food culture, generates a significant amount of by-products that, if not appropriately managed, can pose considerable environmental challenges. This study examined six olive cakes (OC) from the Trás-os-Montes and Alto Douro regions, collected on different dates and mills: two obtained by pressing (COC), two by centrifugation (TPOC), including one partially pitted and one dehydrated, and two exhausted (EOC), which were subjected to conventional chemical analyses, namely dry matter (DM), organic matter (OM), crude fat (CF), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) profiling fatty acid (FA) and phosphorus and phytic acid content. The dehydrated TPOC had only 8% moisture content (due to drying), followed by EOC with 10% and COC (65–79%). The CF content was high in COC 1 (14.5% in DM), residual in EOC (1.5%) and intermediate in TPOC (9–10%). CP ranged from 5.3 to 7.3%. Notably, NDF levels were high (>65% in 5 samples; pitted TPOC 57.4%) and very lignified (ADL > 23%). Different FA profiles were observed: COC had the highest monounsaturated (76.36 g/100 g), while EOC had the highest saturated (16.56 g/100 g) and polyunsaturated (14.14 g/100 g). Phosphorus and phytic acid content (g/100 g) of EOC 2, TPOC pitted, TPOC dehydrated, COC 1 and COC 2 showed similar values to each other (mean of 0.12 ± 0.02 and 0.44 ± 0.0, respectively), with EOC 1 having the lowest levels (0.07 ± 0.01 and 0.26 ± 0.04, respectively). These results highlight the potential of OCs, especially dry TPOC, which offers transport, conservation and utilisation benefits.

Broiler farming is a significant source of gaseous emissions. The aim of this study was to assess the effects of different litter additives on the emission of NH₃, N₂O, CO₂, and CH₄ during broiler housing and subsequent manure storage. The gaseous emissions from the housing facilities were evaluated during one fattening cycle in environmentally controlled rooms with three different additives applied to the litter material (10% w/w aluminum sulphate or biochar and 2.50 mg m⁻² urease inhibitor), as well as a control. A storage experiment was conducted under laboratory conditions for 90 days to evaluate the influence of these three additives on gaseous losses. During broiler housing, the results indicated that NH₃ emissions were reduced significantly (40–60%) by litter additives, while global warming potential (GWP) emissions were reduced significantly (31%) by Alum. The addition of Biochar (a 58% reduction) had the same significant effect as Alum (a 60% reduction) to mitigate these losses. The re-application of Urease (a 41% reduction) may be required to reach an equal or higher reduction. During storage, NH₃ and GWP emissions were not significantly affected by the litter additives. During broiler housing and subsequent manure storage, NH₃ emissions were reduced significantly (22–41%) by litter additives, whereas GWP emissions did not decrease significantly. Globally, it can be concluded that Biochar appears to be a good alternative to Alum due to its equal effectiveness in mitigating NH₃ losses, without increasing the GWP potential in the housing and avoiding pollution swapping.

The olive oil agro-industry generates large quantities of by-products, such as olive cake (OC), whose sustainable valorisation in animal feed can contribute to the principles of circular economy, waste reduction, and resource efficiency. This study evaluated the effects of incorporating OC into the diets of growing Bísaro pigs, focusing on productive parameters and the apparent total tract digestibility (ATTD). Two trials were carried out. In the first trial, 25 pigs were fed five diets containing 0, 5, 10, 15, and 20% exhausted OC (EOC) for 15 days. The results showed a linear decrease in ATTD with increasing EOC levels (p < 0.001), but the increased feed intake compensated for the reduced digestibility, and growth performance was maintained. The initial and final live weight (LW), average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were not affected (p > 0.05). In the second trial, 40 pigs were fed five diets for 82 days: a control diet and four diets incorporating 10% crude OC, 10% two-phase OC, 10% EOC, and 10% EOC with 1% olive oil. No significant differences were observed in final weight, ADG, ADFI, FCR, or the digestibility of DM, OM, CP, CF, and NDF. The results suggest incorporating moderate levels of OC into Bísaro pig diets could be a viable strategy for valorising by-products, reducing agro-industrial waste and increasing sustainability in animal production. In addition, the inclusion of OC had no negative impact on animal performance, highlighting the potential of OC as a sustainable ingredient for animal feed, which aligns with the objectives of the circular economy and sustainable livestock farming practices.

The olive oil industry generates large quantities of olive cake (OC), making its use in animal feed an environmentally sustainable alternative. Considering that the ham of Bísaro pigs is traditionally used for the production of cured ham, the analysis of raw meat is essential to understand how diet influences its quality before the maturation process. This study examined the effect of different types of OC in the diets of Bísaro pigs, focusing on the chemical compositions and fatty acid profiles of three fresh ham muscles—biceps femoris (BF), semimembranosus (SM), and semitendinosus (ST). Forty Bísaro pigs were assigned to five diets: control (CD), 10% raw OC (COC), two-phase OC (TPOC), exhausted OC (EOC), and exhausted OC with 1% olive oil (EOC-OO). The diets significantly influenced moisture, protein, collagen, and haem pigments (p < 0.05). TPOC had the highest moisture content, while CD had the lowest. Protein levels were higher in BF and SM for OC-fed pigs. Collagen in ST was highest in CD and lowest in EOC. Haem pigments varied, with EOC highest in BF and ST and EOC-OO highest in SM. Significant MUFA differences were found in BF (p < 0.001), highest in CD and lowest in TPOC. PUFA levels and the PUFA/SFA ratio were highest in TPOC (p < 0.001), while SFA remained unchanged. The results suggest that up to 10% OC can be included in pig diets without compromising meat quality, but factors such as economic viability and nutritional variability must be considered. This study provides new insights into how OC affects muscle composition, contributing to optimizing feeding strategies for better meat quality and sustainability.

With the aim of improving animal health and productivity, plants or plant extracts that have antimicrobial, antifungal and antioxidant properties are often used in studies with broilers. The aim of this work was to investigate the effect of Urtica urens in broilers. Ninety male Ross chicks were used, randomly placed in 30 pens (three broilers per pen). The broilers were assigned to three treatment groups: group CT (control) received a basal diet; group UU1 received a basal diet with 1% dried Urtica urens; and group UU2 received a basal diet with 2% dried Urtica urens. Each treatment consisted of two feeds, distributed from day 1 to 15 (starter) and from day 15 to 36 (grower). As a result of this study, broilers in the UU1 treatment group had higher weight on day 15 (p = 0.029) and day 36 (p = 0.014) than those in treatments CT and UU2 and a higher daily weight gain between days 1 and 15 (p = 0.028) and days 1 and 36 (p = 0.014). Broilers in the UU1 and UU2 groups had lower serum HDL cholesterol (88.8 and 88.9 mg/dL, respectively) than the CT (96.1 mg/dL). In conclusion, the use of dried Urtica urens at 1% as an additive in broiler diets may affect growth performance and blood HDL cholesterol.

Since the global restrictions on antibiotics in poultry systems, there has been a growing demand for natural and sustainable feed additives for disease prevention and poultry nutrition. This study evaluated the effects of incorporating sugarcane bagasse (SCB) lignin into broiler chicken diets. The performance of the chickens, including body weight, feed intake, and mortality, as well as intestinal histomorphometry, and cecum content pH, microbiota, and volatile fatty acids were assessed. In addition, we also aimed to validate an in vitro gastrointestinal tract (GIT) model developed by Carvalho et al. (2023). One hundred and eight 1-day-old Ross 308 chicks were randomly and equally divided into two groups. The first group was fed a basal diet (BD group), while the second group was fed a basal diet supplemented with 1% (w/w) SCB lignin (BD + SCB lignin group) for 36 days. The in vivo conditions of the chicken GIT were replicated in an in vitro model. In the in vivo study, SCB lignin increased cecum acetate and butyrate levels while reducing Bifidobacterium and Enterobacteriaceae, without affecting productivity (body weight, feed intake, and mortality). The in vitro assessment reflected microbiota trends observed in vivo, although without statistical significance. The divergence in organic acid production between the in vivo and in vitro conditions likely resulted from issues with inoculum preparation. This study demonstrates that SCB lignin incorporation positively influences cecal microbiota composition without impacting the animals’ productivity and physiology, suggesting its potential as a functional feed additive. For a more reliable in vitro model, adjustments in inoculum preparation are necessary.