Nutrient Digestibility, Growth, Mucosal Barrier Status, and Activity of Leucocytes From Head Kidney of Atlantic Salmon Fed Marine- or Plant-Derived Protein and Lipid Sources

Nutrient digestibility, growth, and mucosal barrier status of fish skin, gills, and distal intestine were studied in Atlantic salmon fed feeds based on marine or plant-derived ingredients. The barrier status was assessed by considering the expression of four mucin genes, five genes that encode antimicrobial proteins, distal intestine micromorphology, and design-based stereology of the midgut epithelium. In addition, the head kidney leukocytes were examined using flow cytometry; to understand the differences in their counts and function. Five experimental feeds containing the main components i) fishmeal and fish oil (BG1), ii) soybean meal (BG2; to induce enteritis), iii) fishmeal as the main protein source and rapeseed oil as the main lipid source (BG3), iv) a mix of plant protein concentrates as the protein sources and fish oil as the lipid source (BG4), and v) plant and marine ingredients in the ratio 70:30 (BG5) were produced for the study. Atlantic salmon with initial weight 72.7 ± 1.2 g was offered the experimental feeds for 65 days. The results revealed that the weights of all fish groups doubled, except for fish fed BG2. Fish fed the BG2 diet had lower blood cholesterol concentration, developed enteritis, had lower expression of muc2 in the distal intestine, and had a compromised barrier status in the intestine. Expression of both the mucin genes and genes that encode antimicrobial peptides were tissue-specific and some were significantly affected by diet. The fish fed BG1 and BG3 had more head kidney lymphocyte-like cells compared to BG5-fed fish, and the phagocytic activity of macrophage-like cells from the head kidney was the highest in fish fed BG1. The intestinal micromorphology and the mucosal mapping suggest two different ways by which plant-based diets can alter the gut barrier status; by either reducing the mucous cell sizes, volumetric densities and barrier status (as noted for BG2) or increasing volumetric density of mucous cells (as observed for BG4 and BG5). The results of the compromised intestinal barrier in fish fed plant ingredients should be further confirmed through transcriptomic and immunohistochemical studies to refine ingredient composition for sustainable and acceptable healthy diets.

Bilberry and Sea Buckthorn Leaves and Their Subcritical Water Extracts Prevent Lipid Oxidation in Meat Products

The aim of this study was to find new sustainable, Nordic natural antioxidant sources, develop subcritical water extraction (SWE) process for recovering the antioxidant compounds from the most potential raw materials, and to test their antioxidative effects in meat products. The antioxidant capacities of water and 50% ethanol (aq) extracts of 13 berry, grain, and horticultural plant materials as well as hexane/ethanol extracted stilbene fractions from pine heartwood and spruce inner bark were measured in hydrophilic and lipophilic systems. Tree, bilberry leaf (BL), and sea buckthorn leaf (SBL) extracts showed the highest antioxidant capacities. BL and SBL were selected for the development of SWE. The optimal conditions for recovering maximal antioxidative capacities were 110 °C/1 min for SBL and 120 °C/1 min for BL. Dried BL and SBL and the respective optimized subcritical water extracts were applied in chicken slices and pork sausage, and their ability to prevent lipid oxidation was evaluated during 8 and 20 days storage, respectively, at 6 °C. All tested plant ingredients effectively prevented lipid oxidation in the products compared to the control samples. Sensory acceptance of the plant ingredients was good, especially in the chicken product. To our knowledge, this is the first study to assess the antioxidant effects of SW extracted berry leaves in meat products.

Physicochemical and Sensory Characteristics of Hybrid Flexitarian Pork Loin Steak Combined with Different Plant Ingredients

This study intended to assess the impacts of the following plant ingredients as treatment named 2.5% alginate paste (TAG), carrot (TRC), red cabbage (TCA), chickpea (Cicer arietinum; TCP), and included in pork loin meat to produce hybrid meat steak (HBM) to provide healthy meat products suitable for the flexitarian consumers. Plant ingredients were added to the treatment groups at 30%. Results illustrate that HBM steaks had higher (p<0.05) moisture content than HBM steaks. In raw HBM steaks, pH, CIE L*, and CIE a* were increased than pork steak. Pork steak and TCP demonstrated the highest (p<0.05) cooking loss followed by TRC, TCA, and TAG, whereas, TRC and TCA had higher (p<0.05) releasing water content followed by pork, TCP, and TAG. HBM steaks demonstrated a lower (p<0.05) Warner-Bratzler shear force value than pork steaks. According to the sensory panel pork steak and TAG had overall higher acceptance (p<0.05) followed by TRC, TCP, and least for TCA, which was suggested as especially suitable for the elderly or kids. The electronic tongue system revealed higher (p<0.05) umami intensity and bitterness in HBM steaks than in pork steak. The richness value was higher in pork steak followed by TAG, TCP, and TRC, and lowest in TCA. Therefore, the current study demonstrated that plant ingredients can successfully be incorporated into pork loin to make suitable flexitarian steak to keep eating meat but in a lower concentration.

Dietary Fibers: Shaping Textural and Functional Properties of Processed Meats and Plant-Based Meat Alternatives

The search for alternative sources of plant-based ingredients to improve the textural and sensory properties of plant-based meat alternatives (PMAs) is a growing trend, with the potential to enhance the sustainability of global food systems. While much focus has been placed on plant-based proteins, it is known today that dietary fibers (DFs) can also play a key role in the textural and other physicochemical properties of traditional processed meat products and PMAs. This review examined the latest scientific literature regarding the advantages of using DF in food. It showcases the latest applications of DF in processed meats, PMAs, and the effects of DF on the functional properties of food products, thereby aiming to increase DF applications to create improved, healthier, and more sustainable meat and PMA foods. The predominant effects of DF on PMAs and processed meats notably include enhanced gel strength, emulsion stability, improved water-holding capacity, and the formation of a uniform, porous microstructure. DF also commonly enhances textural properties like hardness, chewiness, springiness, and cohesiveness. While the impact of DF on processed meats mirrors that of PMAs, selecting the right DF source for specific applications requires considering factors such as chemical structure, solubility, size, concentration, processing conditions, and interactions with other components to achieve the desired outcomes.

Effects of a Plant-Based Diet During the First Month of Feeding on Alevin Rainbow Trout (Oncorhynchus mykiss) in the Development of Tongue Sensory System Regulating Feeding Behavior

Taste perception is essential for animals to detect nutrients, providing critical dietary information necessary for growth and survival. Since the early growth performance of alevin rainbow trout (Oncorhynchus mykiss) can be affected by food intake influenced by terrestrial ingredients without fish meal and fish oil, our study aimed to evaluate the role of taste receptors in nutrient detection and the associated signaling pathways leading to central nervous system activation in the regulation of feeding behavior. We conducted a nutritional experiment from the first feeding to 30 days, comparing the performance of fish fed a commercial-like diet (C diet: a blend of fish meal, fish oil, and plant ingredients) with those on a totally plant-based diet (V diet). After 5 and 30 days of feeding, fish were fasted for 16 h and then fed either the C or V diet, with sampling conducted at 20 min and 6 h post-meal. We evaluated the expression of nutrient-sensing genes related to fatty acids, amino acids, and sweetness, and taste receptor genes for flavors. Additionally, we examined calcium signaling pathways in the tongue, focusing on indolamine and catecholamine pathways, alongside appetite-regulating neuropeptides in the brain and intestinal hormones in the gut of alevins. Results indicated that fish on the V diet experienced a decrease in body weight gain starting 10 days after feeding to 30 days, along with changes in feed intake during the periods of 0-10 days and 21-30 days after the first meal. In tongue tissue, after 5 days of feeding, fish on the C diet showed a slight upregulation of nutrient taste receptors, but not those related to flavor, along with an upregulation of the calcium signaling pathway. By 30 days, there was a general upregulation of nutrient and flavor taste receptors, although the calcium signaling pathway showed less clear evidence of regulation. A significant dysregulation of the serotonin pathway, along with its degradation, was observed in the tongues of fish fed the V diet at both 5 and 30 days. For the first time in fish, catecholamine quantification levels in the tongue emerged as a potential marker for nutrient detection, with high quantification of L-DOPA after 5 days on the V diet, but much lower after 30 days. This impaired monoamine and catecholamine turnover in the tongue could be linked to a failure in activating the tongue-brain axis, potentially contributing to reduced food intake, as indicated by poorly regulated brain neuropeptides but also intestinal hormones in fish fed the V diet after 30 days. Overall, these findings demonstrate that the V diet disrupts the feeding response at an early stage, underscoring the heightened sensitivity of rainbow trout alevins' tongue sensing systems to novel food sources during critical early development.