The solid-state fermentation (SSF) efficiency of Bacillus licheniformis ATCC 21424 (BL) on various agro-industrial by-products such as oilseed cakes [hemp (HSC), pumpkin (PSC), and flaxseed (FSC)] was evaluated by examining the nutritional composition, reducing sugars, and in vitro protein digestibility (IVPD) for use in animal nutrition. SSF significantly decreased crude protein, along with changes in the total carbohydrates (p < 0.05) for all substrates fermented. An increase in crude fat for HSC (1.04%) and FSC (1.73%) was noted, vs. PSC, where the crude fat level was reduced (−3.53%). Crude fiber does not differ significantly between fermented and nonfermented oilseed cakes (p > 0.05). After fermentation, neutral detergent fiber (NDF) and acid detergent fiber (ADF) significantly increased for HSC and FSC (p < 0.05), as well as for PSC despite the small increase in ADF (4.46%), with a notable decrease in NDF (−10.25%). During fermentation, pH shifted toward alkalinity, and after drying, returned to its initial levels for all oilseed cakes with the exception of PSC, which maintained a slight elevation. Further, SSF with BL under optimized conditions (72 h) increases the reducing sugar content for FSC (to 1.46%) and PSC (to 0.89%), compared with HSC, where a reduction in sugar consumption was noted (from 1.09% to 0.55%). The viable cell number reached maximum in the first 24 h, followed by a slowly declining phase until the end of fermentation (72 h), accompanied by an increase in sporulation and spore production. After 72 h, a significant improvement in water protein solubility for HSC and FSC was observed (p < 0.05). The peptide content (mg/g) for oilseed cakes fermented was improved (p < 0.05). Through gastro-intestinal simulation, the bacterial survivability rate accounted for 90.2%, 101.5%, and 85.72% for HSC, PSC, and FSC. Additionally, IVPD showed significant improvements compared to untreated samples, reaching levels of up to 65.67%, 58.94%, and 80.16% for HSC, PSC, and FSC, respectively. This research demonstrates the advantages of oilseed cake bioprocessing by SSF as an effective approach in yielding valuable products with probiotic and nutritional properties suitable for incorporation into animal feed.

The growing consumption of oilseed-pressed cakes (OSCs), a largely underutilized feedstock, plays a significant role in animal feed. The study evaluates the use of three OSCs—flax (FSC), pumpkin (PSC), and hemp (HSC)—as substrates for Bacillus subtilis ATCC 6051a (BS) in a solid-state fermentation (SSF) to enhance enzyme production and probiotic viability. The SSF process was assessed to evaluate the microbial growth, sporulation efficiency, enzymatic activity (protease, cellulase, xylanase, and phytase), and in vitro digestibility of fermented substrates. The results indicate that bacterial growth and sporulation varied significantly among substrates (p < 0.05). FSC presents the highest spore resistance (86.52%), followed by PSC (82.87%) and HSC (81.29%). Notably, protease was highest in HSC (184.67 U/g), while FSC supported maximum cellulase activity. HSC exhibited superior xylanase (1.86 ± 0.043 U/g DW, p < 0.05) and phytase production, while pH analysis indicated a shift toward alkalinity in PSC and HSC due to proteolytic activity. FSC maintained the most stable bacterial population during digestion, suggesting its potential as a probiotic carrier. These findings highlight that fermentation of OSCs with BS improved their nutritional value and can be used as a sustainable solution in feeding programs for piglets.

This study investigated the possibility of partial replacement of genetically modified soybean meal (SBM) with raw white lupin (WL) seeds in growing pigs’ diets and determined its impact on performance [body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI)], meat quality, and fatty acid profile (FA). A total of 54 male crossbred pigs [(Topigs Large White × Norsvin Landrace) × Duroc], aged 12 weeks, with an initial average BW of 30.30 ± 0.77 kg, were divided into three dietary groups of 18 piglets each. The control group (CON) was fed a standardized SBM-based complete feed. In the experimental groups (WL1 and WL2) the SBM was replaced with increasing levels of WL seeds [WL1-5.0% and WL2-10.0% (grower period, 30–60 kg BW), and WL1-7.0% and WL2-14.0% (finisher period, 61–110 kg BW)]. All diets were formulated to be isocaloric and isonitrogenous with similar content of total lysine and sulphur amino acids, calcium, and available phosphorus. At the end of 83 days’ fattening trial, the animals were slaughtered. Longissimus dorsi muscle (LD) was sampled for analyses of the physicochemical traits. The results show that increasing the dietary raw WL concentration decreased final BW (p = 0.039), ADG (p < 0.0001), and ADFI (p = 0.004) throughout the experimental period, especially in the second phase of feeding. Dietary treatments did not affect the pigs’ blood biochemical constituents. Concerning LD muscle characteristics, the redness color (a*) and collagen content was higher (p < 0.0001) in the WL1/WL2 vs. CON group. Beneficial decrease in the values of some textural attributes (hardness, gumminess, chewiness, and resilience) of LD in the WL1/WL2 vs. CON group was registered. The use of WL had a significant effect on the content of FAs, especially for eicosapentaenoic (p = 0.014) and n-3 PUFA (p = 0.045), which were higher than those fed the CON diet. In conclusion, WL could be used as a replacement of SBM in growing–finishing pigs’ diets, with significant improvements in the meat fatty acid profile and technological properties.

This study aimed to investigate the possibility of partial replacement of genetically modified soybean meal (SBM) with raw white lupin (WL) seeds in a growing pigs’ diets and to determine its impact on performance [body weight (BW), average daily gain (ADG), average daily feed intake (ADFI)], meat quality and fatty acid profile. A total of 54 male crossbred pigs (Topigs Large White x Norsvin Landrace) x Duroc with an initial average body weight of 30.30 kg were divided into three dietary groups of 18 piglets each. The control group (CON) was fed a standardized SBM-based complete feed. In the experimental groups (WL1, WL2) the SBM was replaced with increasing levels of WL seeds [WL1-5.0% and WL2-10.0% (grower period, 30-60 kg BW), and WL1-7.0% and WL2-14.0% (finisher period, 61-110 kg BW)]. All diets were calculated to be isonitrogenous and isocaloric with similar content of total lysine and sulphur amino acids, calcium, and available phosphorous. After 83 days of fattening, the animals were slaughtered. (LD) muscle was sampled for analyses of the physicochemical traits. The results show that increasing the dietary raw WL concentration, decreased final BW (P = 0.039), ADG (P < 0.0001), and ADFI (P = 0.004) throughout the experimental period, especially in the second phase of feeding (finisher, 61-110 kg). Dietary treatments did not affect the pigs’ blood biochemical constituents. Concerning LD muscle characteristics, the redness color (a*) and collagen content was higher (P < 0.0001) in the WL-fed vs. CON group. Beneficial decrease in the values of some textural attributes (hardness, gumminess, chewiness, resilience) of LD in WL-fed vs. CON group was registered. The use of WL had a significant effect on the content of FAs, especially for eicosapentaenoic (P = 0.014), and n-3 PUFA (P = 0.045), which were higher than those fed CON diet. In conclusion, WL could be used as a replacement of SBM in the diets of growing-finishing pigs with significant improvement of meat fatty acid profile and technological properties.

Solid-state fermentation (SSF) is a long-established biotechnological approach gaining renewed interest for its ability to enhance nutrient availability and improve the functional properties of agro-industrial by-products. This strategy is particularly relevant for early post-weaning piglets, which are highly susceptible to weaning stress due to an immature digestive system and a gut microbiota not yet adapted to solid feed. In this study, the fermentation parameters of flaxseed cake were optimized using a Plackett–Burman experimental design. Protease activity was selected as the response variable due to its relevance for improving protein degradation and potential digestibility in fermented feed ingredients. Accordingly, based on the statistical analysis, the conditions selected for the in vivo trial were 1% molasses, 0.5% yeast extract, 0.05% CaCl₂, 0.5% NaCl, 7.5% inoculum (4.12 × 10⁹ CFU/mL), 60% moisture, and 72 h fermentation. Fermentation time was identified as the main factor positively influencing protease production, while higher CaCl₂ concentrations and inoculum levels negatively affected enzyme activity. Optimization increased protease activity, microbial viability and free amino acid content. In addition, SSF reorganizes the carbohydrate profile by reducing structural fiber fractions, with neutral detergent fiber and acid detergent fiber decreasing by 27% and 29%, respectively, while simultaneously increasing soluble carbohydrates by 14.67%. Phytic acid content being also reduced by 23.81%. A pilot nutritional trial on post-weaned piglets (35 days old) showed that including 8% fermented flaxseed cakes (FFSC group) improved body weight, average daily gain, feed conversion ratio, and diarrhea score, without affecting average daily feed intake, compared with 8% unfermented flaxseed cakes (FSC group). These performance improvements were accompanied by changes in fermentation metabolites and gut microbial composition. Lower isovalerate concentrations suggested reduced proteolysis, while higher propionate levels may contribute to increased blood glucose availability in the FFSC group. These changes coincided with a shift in microbial composition, characterized by a reduced abundance of methanogenic archaea and increased abundances of taxa such as Lactobacillus, Enterococcus, and members of the Lachnospiraceae and Eubacteriaceae families.

Raw rapeseed cake represents a viable alternative protein source for broiler diets, and its fermentation may reduce anti-nutritional factors while improving its feeding value. This 35-day study involved 300 one-day-old ROSS 308 chicks (three groups, four replicates/group, with 25 broilers/replicate) raised on wood shavings (16 broilers/m²). Broilers received either a control diet (corn–soybean meal) or diets supplemented with 200 g/kg of RRCs (raw rapeseed cakes) or fermented rapeseed cakes (FRCs). At the end of the trial, eight broilers per group were slaughtered, and breast and thigh samples were collected. The nutritional quality of the meat was assessed by proximate composition, fatty acid profile, and health-related lipid indices. In addition, oxidative status during shelf-life storage was evaluated based on myoglobin content (Mb), metmyoglobin concentration (metMb), total antioxidant capacity (TAC), and lipid peroxidation, determined as thiobarbituric acid reactive substances (TBARS). The omega-3 fatty acid content in fresh breast and thigh samples was significantly higher in RRC and FRC groups compared to C (p = 0.014; p = 0.0001), which significantly decreased the omega-6/omega-3 ratio for both samples (p = 0.0001). The TBARS values exhibited a significant decrease (p < 0.0001) between groups for breast and thigh samples. The TAC values showed significantly higher antioxidant capacity in RRC and FRC breasts and thigh samples compared to C, considering both group differences (p < 0.0001) and shelf-life evaluation (p = 0.001). In thigh samples, the RRC group showed lower metMB values compared to the control group (p = 0.042), whereas differences in breast samples were not statistically significant (p = 0.054). Healthy lipid indexes registered significantly lower values for experimental groups, both for breast and thigh, and for linoleic/α-linolenic acid ratio (p = 0.0001), but for atherogenicity index (AI) (p = 0.0001) and thrombogenic index (TI) (p = 0.0001) only for the RRC group, while nutritive value index (NVI) significantly increased (p = 0.0001) on both groups. In conclusion, RRC and FRC may represent sustainable alternatives to soybean meal in broiler nutrition, supporting improvements in meat lipid profile and oxidative stability. Overall, the RRC group showed more significant effects on n-3 fatty acid enrichment and lipid quality indices, whereas the FRC mainly influenced proximate composition and selected color parameters.