New sustainable sources of feeds, which can enhance the health and welfare of farm animals, lower feeding costs, and lead to safer products, are of high priority in modern animal production systems. In the present study, a novel silage created from Greek olive, winery, and feta cheese waste by-products, was evaluated as a feed ingredient at different inclusion rates (0%, 5% or 10%) in 34-day-old weaned pigs. The potential beneficial effects on performance, health and intestinal digesta microflora balance of the pigs were evaluated. Additionally, chemical, microbiological and quality analysis of the meat was carried out. Results showed no detrimental effects (p > 0.05) on the pigs’ performance and no significant changes (p > 0.05) in meat pH, color and chemical analysis. Ileum and cecum microflora populations (total anaerobes, Lactobacillaceae) were positively affected (p ≤ 0.05) by the dietary usage of the silage. The microbial populations (Clostridium spp.) of belly meat cuts were positively modified (p ≤ 0.01). The concentration of total phenols in the meat cuts were increased (p ≤ 0.05) and their resistance to oxidation was improved (p ≤ 0.05). In addition, the fatty acid profile of the meat lipids (polyunsaturated and n-3 fatty acids) was positively modified (p ≤ 0.001).

The aim of this study was to evaluate whether dietary supplementation with an innovative silage (IS) created using 60% olive mill waste, 20% grape pomace, and 20% deproteinised feta cheese waste solids can modulate the composition of the intestinal microbiota in weaned (Exp. 1) and finishing (Exp. 2) pigs. In Exp. 1 (40 day supplementation), forty-five crossbred weaned pigs were randomly assigned to the 0% (Control), 5%, or 10% IS groups (15 replicates/experimental diet). In Exp. 2 (60 day supplementation), eighteen finishing pigs from Exp. 1 were fed the control diet for 8 weeks before being re-assigned to their original experimental groups and fed with the 0% (Control), 5%, or 10% IS diets (six replicates/experimental diet). Performance parameters were recorded. Ileal and caecal digesta and mucosa were collected at the end of each experiment for microbiota analysis using 16S rRNA gene sequencing (five pigs/experimental diet for Exp. 1 and six pigs/experimental diet for Exp. 2). No significant effects on pig growth parameters were observed in both experiments. In Exp. 1, 5% IS supplementation increased the relative abundance of the Prevotellaceae family, Coprococcus genus, and Alloprevotella rava (OTU_48) and reduced the relative abundance of Lactobacillus genus in the caecum compared to the control and/or 10% IS diets (p < 0.05). In Exp. 2, 5% IS supplementation led to compositionally more diverse and different ileal and caecal microbiota compared to the control group (p < 0.05; p = 0.066 for β-diversity in ileum). Supplementation with the 5% IS increased the relative abundance of Clostridium celatum/disporicum/saudiense (OTU_3) in the ileum and caecum and Bifidobacterium pseudolongum (OTU_17) in the caecum and reduced the relative abundance of Streptococcus gallolyticus/alactolyticus (OTU_2) in the caecum compared to the control diet (p < 0.05). Similar effects on C. celatum/disporicum/saudiense and S. gallolyticus/alactolyticus were observed with the 10% IS diet in the caecum (p < 0.05). IS has the potential to beneficially alter the composition of the gastrointestinal microbiota in pigs.

Nowadays, the global animal industry faces considerable challenges in securing sufficient feed resources. Responding to consumer demands for reduced use of antibiotics in animal nutrition, better animal welfare status, and reduced impact on the environment, there is an increased urgency to develop innovative functional feeds with a reduced environmental footprint and the ability to improve meat quality and safety. In an effort to explore innovative feed ingredients for growing pig diets, the combined dietary supplementation of Tenebrio molitor larvae and chitosan was investigated. An experimental trial was performed with 48 weaned pigs (34 days of life; mixed sex) that were randomly assigned to four treatment groups (with six males and six females each): Group A (control), Group B (supplemented with T. molitor larvae at 10%), Group C (supplemented with chitosan at 0.05%), and Group D (supplemented with both ingredients at 10% and 0.05%, respectively). On the 42nd day of the experimental trial, samples of blood, feces, and carcass parts were taken for analysis. The results indicated that the insect larvae meal significantly improved (p < 0.05) overall performance, increased (p < 0.05) blood red blood cell content, increased meat phenolic content (p < 0.05), improved meat oxidative stability (p < 0.05), and affected meat fatty acid profile (p < 0.05). On the other hand, chitosan had no significant effect on overall performance (p > 0.05), but it significantly increased blood lymphocyte content (p < 0.05), affected the fecal microbiota (p < 0.05), improved meat oxidative stability (p < 0.05), increased meat phenolic content (p < 0.05), and affected meat fatty acid composition (p < 0.05) and (p < 0.05) meat color. Finally, the combined use of both T. molitor and chitosan significantly affected some important zootechnical parameters (p < 0.05), fecal microbial populations (p < 0.05), meat color (p < 0.05), and fatty acid profile (p < 0.05). Further investigation into the potential interaction between insect larvae meals and chitosan in pig diets is advised.

In modern animal production systems, the use of alternative feed sources is essential for reducing production costs, protecting natural resources, and improving meat quality. This study evaluated the impact of a unique silage—one produced by agro-industrial by-products—on the growth, meat quality, and health parameters of finishing pigs. Eighteen pigs (120 days old, 59.47 ± 0.85 kg) were randomly assigned to three dietary treatments containing 0% (A), 5% (B), or 10% (C) silage. After 60 days, blood samples were collected for hematological and biochemical analyses; this was followed by slaughter for the collection of muscle tissues (triceps brachii, external abdominal oblique) and intestinal digesta (ileum, cecum). Final body weight did not differ among groups (124.54 ± 1.51 kg), and meat composition (fat, protein, collagen, and ash) and pH were unaffected (p > 0.05). ALT levels were significantly lower in group C than in A (p = 0.030). In the ileum, Enterobacteriaceae and Enterococci populations decreased, whereas Lactobacilli increased in B and C (p ≤ 0.05). Cecal Enterococci were reduced in both B and C (p ≤ 0.01), with a tendency for increased Lactobacilli in B. Group C showed higher total phenolic content (p ≤ 0.05) and an improved ω-6/ω-3 ratio (15.09 vs. 17.54 in A). The TBARS values did not differ among treatments. Campylobacter jejuni counts were lower in treatment C, and no Salmonella or Listeria monocytogenes were detected in any samples. The meat color of the triceps brachii was redder in treatments B and C (p = 0.001). Overall, the innovative silage increased phenolic content, supported improvements in gut microbiota, and maintained meat quality, indicating its potential as a sustainable feed ingredient.

Current consumer trends for meat production with reduced antibiotic use constitute huge challenges in animal farming. Using indigenous raw materials such as aromatic or medicinal plants or their extracts could positively affect or retain animals’ health. The present study aimed to evaluate the effects of medicinal plant extracts and essential oils on pig performance parameters, health indices and meat quality. A phytobiotic mixture (PM) consisting of oregano (Origanum vulgare subsp. hirtum) essential oil, rock samphire (Crithmum maritimum L.) essential oil, garlic flour (Allium sativum L.) and false flax flour (Camelina sativa L. Crantz) was used in pig diets, containing in the experimental trials two different proportions of the oregano essential oil (200 mL/t of feed vs. 400 mL/t of feed). Three groups of weaned pigs were fed either the control diet (CONT) or one of the enriched diets (PM-A or PM-B, 2 g/kg). After a 43-day feeding period, at 77 days of age, blood was taken from the jugular vein for biochemical and hematological tests, and eight pigs were humanely slaughtered. A microbiological analysis of intestinal digesta from the ileum and caecum was conducted. Additionally, meat tissue cuts (biceps femoris, external abdominal and triceps brachii) were collected for a chemical analysis, fatty acid lipid profile and oxidative stability testing. The statistical analysis revealed no differences (p > 0.05) in the body weights and growth rates among the groups. An increase (p < 0.05) in total aerobic bacteria was detected in the ileum of group PM-A, while Escherichia coli (E. coli) counts were reduced (p < 0.05) in group PM-B. In the caecum, reductions in Enterobacteriaceae and Lactobacillaceae counts were observed in groups PM-A and PM-B. Concentrations of malondialdehyde (MDA) as an indicator of lipid peroxidation were significantly reduced (p < 0.05) in triceps brachii and biceps femoris for both groups PM-A and PM-B (day 0). A reduction (p < 0.05) in MDA was noticed in triceps brachii and external abdominal meat samples (day 7) for groups PM-A and PM-B. In addition, the fatty acid profile of the meat lipids (ΣPUFA, h/H and PUFA/SFA ratios) was positively modified (p < 0.05) in the ham and belly cuts. The addition of the PM significantly (p < 0.05) affected the redness of the ham and shoulder meat (a* value increased), the yellowness of only the ham (b* value decreased) and the lightness of both belly (L* value increased) and ham samples (L* value decreased). The meat proximate analysis, as well as hematological and biochemical parameters, did not identify any differences (p > 0.05) between the groups. In conclusion, the two investigated mixtures could be used in weaned pigs’ diets, with positive results in intestinal microbial modulation, oxidative stability, fatty acid profile and color characteristics of the pork meat produced.