The gastrointestinal tract of livestock and poultry is prone to challenge by feedborne antigens, pathogens, and other stress factors in the farm environment. Excessive physiological inflammation and oxidative stress that arises firstly disrupts the intestinal epithelial barrier followed by other components of the gastrointestinal tract. In the present review, the interrelationship between intestinal barrier inflammation and oxidative stress that contributes to the pathogenesis of inflammatory bowel disease was described. Further, the role of naturally existing immunomodulatory nutrients such as the omega-3 polyunsaturated fatty acids, citrus pectin, and milk-derived exosomes in preventing intestinal barrier inflammation was discussed. Based on the existing evidence, the possible molecular mechanism of these bioactive nutrients in the intestinal barrier was outlined for application in animal diets.

Marine and plant-based omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are widely added to animal diets to promote growth and immunity. We tested the hypothesis that eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and their 1:2 combination could counteract acute or long-term damage of lipopolysaccharides (LPS), dextran sodium sulphate (DSS) and hydrogen peroxide (H₂O₂) in Intestinal Porcine Epithelial Cell line-J2 (IPEC-J2). The results showed that 24 h treatment with EPA or DHA exhibited proliferative effects in IPEC-J2 cells at low to moderate concentrations (6.25–50 μM) (p < 0.05). Further, 24 h pretreatment with individual DHA (3.3 µM), EPA (6.7 µM) or as DHA:EPA (1:2; 10 µM) combination increased the mitochondrial activity or cell membrane integrity post-LPS (24 h), DSS (24 h) and H₂O₂ (1 h) challenge (p < 0.05). Additionally, DHA:EPA (1:2, 10 µM) combination decreased the apoptotic caspase-3/7 activity around twofold after 24 h LPS and DSS challenge (p < 0.05). Our study confirms the proliferative and cytoprotective properties of EPA and DHA in IPEC-J2 cells. Increased intracellular mitochondrial activity and cell membrane integrity by ω-3 PUFAs can play a role in preventing enterocyte apoptosis during acute or chronic inflammatory and oxidative stress.

Over the past decades, several studies investigated the health-promoting functions of milk peptides. However, to date many hurdles still exist regarding the widespread use of milk-derived bioactive peptides, as they may be degraded during gastrointestinal digestion. Thus, the aim of our study was to in vitro digest intact whey protein isolate (WPI) and casein proteins (CNP), mimicking in vivo digestion, to investigate their bioactive effects and to identify the potential peptides involved. Whey protein isolate and CNP were digested using a pepsin-pancreatin protocol and ultra-filtered (3-kDa cutoff membrane). A permeate (3 kDa) were obtained. Soy protein was included as a control (CTR). Angiotensin-1-converting enzyme inhibitory (ACE1-I) and antioxidant activity (AOX) were assessed and compared with those observed in undigested proteins and CTR. Furthermore, the permeate was characterized by nano-liquid chromatography electrospray ionization tandem mass spectrometry (LC-nano ESI MS/MS) using a shotgun peptidomic approach, and retentate was further digested with trypsin and analyzed by MS using a shotgun proteomic approach to identify potentially bioactive peptides. Further, the effects of WPI, CNP, and CTR retentate on cell metabolic activity and on mucus production (MUC5AC and MUC2 gene expression) were assessed in intestinal goblet HT29-MTX-E12 cells. Results showed that WPI permeate induced a significant ACE1-I inhibitory effect [49.2 ± 0.64% (SEM)] compared with undigested WPI, CNP permeate, and retentate or CTR permeate (10.40 ± 1.07%). A significant increase in AOX (1.58 ± 0.04 and 1.61 ± 0.02 µmol of trolox AOX equivalents per mg of protein, respectively) upon digestion was found in WPI. Potentially bioactive peptides associated with ACE1-I and antihypertensive effects were identified in WPI permeate and CNP retentate. At specific concentrations, WPI, CNP, and CTR retentate were able to stimulate metabolic activity in HT29-MTX-E12 cells. Expression of MUC5AC was increased by CNP retentate and unaltered by WPI retentate; MUC2 expression was significantly increased by 0.33 mg/g of CNP and reduced by 1.33 mg/g of CNP. Our results confirm that milk proteins may be rich sources of bioactive compounds, with the greatest beneficial potential of CNP at the intestinal goblet cell level.

Limosilactobacillus reuteri and Lactiplantibacillus plantarum strains, previously isolated from weaned piglets, were considered for the evaluation of their adhesive characteristics. Lactobacilli were treated with LiCl in order to remove the surface protein layer, and probiotic activity was compared with those of untreated strains. The autoaggregation, co-aggregation to E. coli F18+, and adhesive abilities of LiCl-treated Limosilactobacillus reuteri and Lactiplantibacillus plantarum were significantly inhibited (p < 0.05) compared with the respective untreated strain. The hydrophobic and basic phenotypes were observed due to the strong affinity to chloroform and low adherence to ethyl acetate. In particular, L. plantarum showed higher hydrophobicity compared to L. reuteri, which may reflect their different colonizing ability. After treatment with LiCl to remove surface proteins, the adherence capabilities of L. reuteri and L. casei on IPEC-J2 cells decreased significantly (p < 0.001) and L. reuteri adhered more frequently. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that both L. reuteri and L. plantarum had several bands ranging from 20 to 100 kDa. Two-dimensional gel electrophoresis showed an acidic profile of the surface-layer polypeptides for both bacterial strains, and more studies are needed to characterize their profile and functions. The results confirm the pivotal role of surface proteins in the probiotic potential of L. reuteri and L. plantarum.

In vitro meat cultivation, a cutting-edge innovation in food science, may represent a more sustainable and ethical source of animal proteins compared with conventionally grown meat. An important challenge for meat cultivation lies in eliminating the use of fetal bovine serum (FBS) in cell culture media due to ethical concerns. Milk whey is a nutrient-rich liquid portion of the milk, derived as a byproduct of dairy industry. Similar to FBS, whey contains proteins that are crucial for nutrition, cell adhesion, and biomolecular transport. In this study, we investigated whether whey proteins (WP) can replace FBS in supporting muscle cell cultivation, using the C2C12 myoblast model. Accordingly, under serum-free conditions, cells were treated with 2 WP mixtures, grouping high (β-LG 1.25%, α-LA 1.25%, BSA 1.25%) and low (β-LG 0.07%, α-LA 0.15%, BSA 0.15%) selected concentrations of individual proteins that positively affected cell growth in a preceding dose-response study. Cells cultured in only basal Dulbecco's Modified Eagle Medium were included as a negative control, and cells cultured in 10% FBS as a positive control. Cells were maintained in the treatment media for 48 h (d 1 and 2) to support myoblast proliferation. Subsequently, all the treatments were replaced with a standard low mitogenic 2% horse serum (HS) medium until full differentiation (d 6). The treatment effects on morphology, viability, and lactate dehydrogenase release were assessed after d 1, 2, and 6, respectively. The results showed that WP stimulated cell proliferation under serum-free culture conditions, similar to the FBS control, and subsequently facilitated myotube formation when the WP or FBS treatments were switched to HS medium. After differentiation, these cells also exhibited increased expression of cell differentiation markers such as creatine kinase and citrate synthase and underwent morphological changes from spindle-shaped cells to fused elongated myotubes, in contrast to the negative control. This study demonstrates that WP are a promising and sustainable alternative for considerably replacing FBS-based growth supplements for use in cultivated animal products.

Due to its nutritional value and versatility, milk is recognized to be one of the most widely consumed beverages worldwide, with a forecasted global consumption of 356 million tons in 2025. Recent updates in legislation and the assessment of their toxicological effects increased attention to the determination of per- and polyfluoroalkyl substances (PFASs), classified as “forever pollutants” for their stability and environmental spread in foods. The present review aims to collect all the information related to milk contamination reported by the scientific literature over the last decade and address the PFAS contamination levels around the globe. Twenty-two studies were found to be published about the detection of PFASs in milk in the period considered in this review, with a total of 824 analyzed samples on a global scale and a maximum of 60 investigated analytes. This review confirms that PFASs, including PFOA and PFOS, are detected in milk worldwide. However, the wide variability in reported concentration levels highlights a critical lack of consistent data and underscores the absence of coordinated, large-scale monitoring programs. This gap in surveillance significantly limits our understanding of actual exposure risks and reinforces the urgent need for comprehensive, systematic research across different regions and production systems.