Protein Digestibility Research Articles

New Pipeline for Analysing Fruit Proteolytic Products Used as Digestive Health Nutraceuticals

Proteolytic products are extensively used in the nutraceutical sector to improve protein digestion and muscle quality in target populations (e.g., athletes or elderly). These products are processed using techniques that often lead to low purity but competitive pricing. Despite their widespread use and well-established production methods, the industry lacks standardized analytical methods for assessing these products and detecting potential fraud. This study proposes a comprehensive and harmonized pipeline for their analysis, which includes quantifying total soluble protein and proteolytic activity, as well as the determination of product stability and protein profile using SDS-PAGE and proteomic techniques. Despite the fact that protease extracts from pineapple had the highest protein content, most of the bromelain remained inactive, unlike in kiwi and papaya. SDS-PAGE revealed partial protein degradation of pineapple extracts, whereas kiwi extracts reflected a lower purification level but a higher protein integrity. The application of proteomic approaches strengthened the identification and origin tracing of the proteases. This study contributes to the development of a robust framework for analyzing proteolytic extracts, spanning from soluble protein quantification to protein profiling and activity determination. It may also ensure reliable supplier selection, high-quality manufacturing practices, and the implementation of optimal storage and formulation strategies in the nutraceutical industry.

Starch in Emulsion-Type Sausage Reduced the Gastric Digestibility of Meat Protein by Reducing the Stability and Increasing the Viscoelasticity of Gastric Digests.

The effect of the addition of native starch (S) and modified starches (distarch phosphate (SP), acetylated distarch phosphate (AP), and starch acetate (SA)) in emulsion-type sausage on the digestion process of meat protein was studied in this work. The addition of native and modified starches reduced the release of -NH2 during the simulated gastric digestion stage, whereas the addition of SA increased the total release of -NH2 after the whole digestion. Peptidomic analysis revealed that the presence of starch decreased the release of peptides in the gastric digestion. The presence of starch reduced the stability of the digests but increased the viscosity of the gastric digestive fluid, which should largely be responsible for the decreased gastric digestibility of meat protein. These results highlighted the physical properties of digests as a key factor affecting the gastric digestion process of meat protein and provided guidance for the application of starches in meat products.

In Vitro Human Gastrointestinal Digestibility and Colonic Fermentation of Wheat Sourdough and Yeast Breads.

Bread can vary in textural and nutritional attributes based on differences in the bread making process (e.g., flour type, fermentation agent, fermentation time). Four bread recipes (BRs) made with sourdough preferments (BR1, white flour; BR2, whole grain flour) or regular yeast breads (BR3, white flour; BR4, whole grain flour) were evaluated for texture, digestibility, and their effect on the metabolic activity and composition of the gut microbiota using texture profile analysis (TPA) coupled with in vitro upper gastrointestinal (GIT) digestion and colonic fermentation (Colon-on-a-plate™ model), using fecal samples from eight healthy human donors. TPA revealed significantly higher values for hardness, fracturability, gumminess, and chewiness, and significantly lower values for springiness, cohesiveness, and resilience with whole grain versus white breads (all p < 0.001); values for springiness, cohesiveness, and resilience were significantly higher for sourdough versus yeast bread (p < 0.001). Nutrient composition and bioaccessibility were generally comparable between sourdough and yeast bread with similar flours. Following simulation of upper GIT digestion, all BRs demonstrated good digestibility of minerals, carbohydrates, and proteins. Colonic fermentation revealed changes in gut microbiota composition, significant increases in short-chain fatty acids, and a significant decrease in branched short-chain fatty acids with all BRs versus a blank. Overall, new insights into wheat bread digestibility and colonic fermentation were provided, which are important aspects to fully characterize bread nutritional profile and potential.

Impact of lipid oxidation products on the digestibility and structural integrity of Myofibrillar proteins during thermal processing

This study explores the effects of lipid oxidation products (LOPs), specifically CHP, t,t-DDE, and MDA, on the digestibility and structural integrity of myofibrillar proteins (MP) during processing. LOPs were first assessed by heating at 180 °C for 15 min, showing a significant reduction in digestibility in MDA-treated samples (65.40 %), followed by t,t-DDE (45.10 %) and CHP (13.07 %). MALDI-TOF MS analysis revealed decreased peptide abundance and lower average molecular weight in t,t-DDE- and MDA-treated samples. Notably, substantial decreases in α-helix content and increases in random coil structures were detected, particularly in MDA-treated samples. Assessments of surface hydrophobicity and thiol content underscored the detrimental impact of secondary LOPs on MP structure. Higher MDA concentrations led to a substantial reduction in intrinsic fluorescence intensity, along with an increase in Schiff base content. A PLS regression model demonstrated strong predictive capabilities for MP digestibility, highlighting the importance of optimizing meat processing parameters to minimize nutritional degradation.

The prognostic value of bioinformatics analysis of ECM receptor signaling pathways and LAMB1 identification as a promising prognostic biomarker of lung adenocarcinoma.

The extracellular matrix (ECM) is a complex and dynamic network of cross-linked proteins and a fundamental building block in multicellular organisms. Our study investigates the impact of genes related to the ECM receptor interaction pathway on immune-targeted therapy and lung adenocarcinoma (LUAD) prognosis. This study obtained LUAD chip data (GSE68465, GSE31210, and GSE116959) from NCBI GEO. Moreover, the gene data associated with the ECM receptor interaction pathway was downloaded from the Molecular Signature Database. Differentially expressed genes were identified using GEO2R, followed by analyzing their correlation with immune cell infiltration. Univariate Cox regression analysis screened out ECM-related genes significantly related to the survival prognosis of LUAD patients. Additionally, Lasso regression and multivariate Cox regression analysis helped construct a prognostic model. Patients were stratified by risk score and survival analyses. The prognostic models were evaluated using receiver operating characteristic curves, and risk scores and prognosis associations were analyzed using univariate and multivariate Cox regression analyses. A core gene was selected for gene set enrichment analysis and CIBERSORT analysis to determine its function and tumor-infiltrating immune cell proportion, respectively. The results revealed that the most abundant pathways among differentially expressed genes in LUAD primarily involved the cell cycle, ECM receptor interaction, protein digestion and absorption, p53 signaling pathway, complement and coagulation cascade, and tyrosine metabolism. Two ECM-associated subtypes were identified by consensus clustering. Besides, an ECM-related prognostic model was validated to predict LUAD survival, and it was associated with the tumor immune microenvironment. Additional cross-analysis screened laminin subunit beta 1 (LAMB1) for further research. The survival time of LUAD patients with elevated LAMB1 expression was longer than those with low LAMB1 expression. Gene set enrichment analysis and CIBERSORT analyses revealed that LAMB1 expression correlated with tumor immune microenvironment. In conclusion, a prognostic model of LUAD patients depending on the ECM receptor interaction pathway was constructed. Screening out LAMB1 can become a prognostic risk factor for LUAD patients or a potential target during LUAD treatment.

Effects of Different Processed Diets on Growth Performance, Blood Parameters, Hair Quality and Fecal Microbiota in Ragdoll Cats.

In recent years, there has been ongoing debate about the dietary choices for pet cats, particularly regarding three options: extruded dry food, cooked meat, and raw meat. Determining which diet is most suitable for a cat's healthy growth still requires substantial empirical support. Our study aimed to evaluate the effects of feeding Ragdoll cats (n = 5/group) extruded dry food (ED), cooked meat (CM), and raw meat (RM) on their growth performance, apparent digestibility, fur condition, blood parameters, fecal scores, and gut microbiota composition. However, our results indicate that different types of diets did not significantly affect the daily weight gain of Ragdoll cats. The CM group showed a significant improvement in the digestibility of dry matter, fat and protein compared to the ED group (p < 0.05) but no improvement in that of fat compared to the RM group. Compared to the ED group, both the CM and RM groups showed significant improvements in fur condition while exhibiting a significant decrease in fecal scores (p < 0.05). The CM and RM groups exhibited enhanced serum antioxidant capacity (p < 0.05) and increased immunity in the cats (p < 0.05). Immunity enhancement in the CM group was significantly higher than that in the RM group(p < 0.05). The ED group showed an increase in the abundance of beneficial bacteria in Ragdoll cat intestines, while the CM and RM groups showed enhancements in the innate microbiota of feline animals. These data, to some extent, suggest that CM is the most suitable diet for Ragdoll cats, but further research on intestine microbiota is still needed. These study findings provide a reference for purebred pet breeding purposes.

Full-fat black soldier fly larvae meal and yellow mealworm meal: Impact on feed protein quality, growth and nutrient utilization of Atlantic salmon (Salmo salar) post smolts

The shift towards insect-based alternatives in aquafeeds stems from the need to reduce the carbon footprint associated with the ingredients used in salmon feeds. In the present study, we describe the effects of full-fat insect meal incorporation on amino acid derivatives in feeds and the growth performance and nutrient utilization of Atlantic salmon post-smolts fed insect meals. A 74-day growth trial was conducted employing 520 fish (143 ± 12.8 g); these fish were fed either a control diet (CO) that contained 20 % fishmeal, 20 % soy protein concentrate (SPC), 14 % wheat gluten, 19 % plant raw materials, 13 % fish oil and 6 % rapeseed oil, or one of four insect meal diets, prepared with either 5 % and 10 % black soldier fly larvae meal (BS5, BS10) or 15 % and 30 % mealworm meal (MW15, MW30), by substituting mainly SPC, wheat gluten and rapeseed oil. The inclusion levels of BS and MW were determined based on their distinct chemical compositions, specifically their lipid content. As regards the results, HPLC-based high-throughput data on amino acid derivatives revealed the following: carboxymethyllysine was significantly higher in the MW30 feed than in BS5, BS10 and MW15 feeds; carboxyethyllysine was higher in the MW15 and MW30 feeds compared to the others; furosine was lower in the MW15 feed compared to the CO, BS5 and MW30 feeds. Regarding the effect of the insect meals on Atlantic salmon post-smolts, their inclusion had no significant effect on feed conversion ratio, health indicators and the retention efficiency of macronutrients. Apparent digestibility coefficients (ADC) of dry matter, lipid, ash and energy were not significantly different. However, protein digestibility in the 30 % MW group (80.4 %) was significantly lower (P ≤ 0.05) compared to the control and BS5 group (84.5 %). Furthermore, the ADC of protein was found to decrease linearly with increasing levels of insect meals, with MW showing a significant relationship (adjusted r2 = 0.77, p = 0.014). Overall, our study highlights the efficacy of 5 and 10 % BS and 15 % MW as ingredients in the feeds of Atlantic salmon. Other focal points included the undesirable amino acid derivatives and a reduction in protein digestibility associated with 30 % of MW in the diet of Atlantic salmon. Hence, future investigations should focus on the effects of feed processing conditions on the protein quality of mealworm before suggesting higher inclusion levels to the feed industry.

Comparative efficacy of amino acid availability and peptidomic analysis of alternative proteins from different sources under dynamic in vitro protein digestion

The increasing global demand for animal protein highlights the critical necessity of exploring alternative protein sources. Accessing the nutritional characteristics of emerging alternative proteins is vital for food processing and consumer acceptance. This study investigated the amino acid availability and peptidomics profiles of plant- (soy), fungal- (filamentous fungus Fusarium venenatum), microalgae- (Nannochloropsis oculata), and insect-based (black soldier fly) proteins using an advanced dynamic in vitro digestion system, with whey protein as a reference. After gastric digestion, soy and mycelial proteins, despite displaying distinct microstructures, exhibited slightly higher protein digestibility levels of 28.79% and 26.36%, respectively, compared to whey protein (22.39%). However, following small intestinal digestion, whey protein (61.31%) significantly outperformed alternative proteins. Mycelial protein (43.71%) exhibited digestibility similar to soy protein (46.12%), markedly surpassing both microalgae protein (33.35%) and insect protein (26.58%). Notably, insect protein achieved an amino acid availability nearly approaching that of whey protein, underscoring its substantial proteolysis capability. Furthermore, microalgae protein produced the highest percentage and number of bioactive peptides under simulated digestion, suggesting potential health benefits such as angiotensin I-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibitor activities, which could mitigate the risk of hypertension and Type 2 diabetes. Alternative proteins from different sources demonstrate diverse digestive mechanisms and proteolysis profiles, thereby bolstering their potential applications as nutritious food ingredients in the future.

Ruminal degradation and intestinal digestion of developed oat (Avena sativa L.) varieties in comparison with barley grain in dairy cows

This study aimed to evaluate the ruminal degradation and intestinal digestion of nutrients of two cultivars of oat grains (CDC Nasser and CDC Seabiscuit) in comparison with a barley grain (CDC Meredith that was considered the control treatment) in dairy cows. Nasser showed higher rumen undegradable protein (RUP; P &lt; 0.01) and intestinal digestible protein ( P &lt; 0.01) than Seabiscuit or control. However, the total digestible protein was not different among grain varieties ( P = 0.25). The in vitro intestinal digestibility of RUP (dIBP) for Nasser was higher than control ( P = 0.02); however, the dIBP in Seabiscuit did not differ from other cultivars. The intestinal digestible rumen bypass starch and total digestible starch were lower in the oat grain varieties than in the control ( P &lt; 0.01). The truly absorbed protein supplied to the small intestine (DVE) was highest for control, intermediate for Seabiscuit, and lowest for Nasser ( P &lt; 0.01). Moreover, control showed a higher estimated feed milk value than oat varieties ( P &lt; 0.01). In conclusion, Seabiscuit shared similar rumen degradation and intestinal digestibility with control suggesting that Seabiscuit oat grain could in some extension replace barley grain in diets for dairy cows.

Impact of early weaning and nutritional interventions on growth performance, digestive metabolism, and serum biomarkers in lambs: A biomechanical perspective

The aim of this study was to investigate the effects of early weaning and nutritional interventions on growth performance, nutrient digestion and metabolism, and serological indices of hu sheep lambs, with a view to providing a basis for the feasibility of early weaning of hu sheep lambs under conditions of supplemental milk replacer. Ninety neonatal hu sheep lambs were weaned at 21 days (n = 60) (divided into two groups: early weaned, EW; and resveratrol-fed, RSV) as well as 49 days (n = 30) (control group, CON) weaning, and the trial period was 90 days. The results showed that: 1) there was no significant difference (P &gt; 0.05) in the initial and final weights of the lambs, and the average daily gain (ADG) of the EW and RSV groups was significantly lower than that of the CON group (P &lt; 0.05) from 31 to 45 days of age. Early weaned lambs were more susceptible to weaning stress compared to late weaned lambs and the effect of nutritional intervention (feeding resveratrol) on lamb growth performance was not significant. 2) The apparent digestibility of crude protein (CP) in the experimental group was significantly lower than that of the control group (P &lt; 0.05), and the nitrogen intake, net protein utilization and protein biological value indexes of lake lambs in the experimental group were significantly different from those of the control group (P &lt; 0.05). 3) Early feeding of resveratrol was not significant in improving the digestive metabolism of nutrients. 4) Early weaning as well as the addition of resveratrol had a significant effect on the serum GLU and TC indexes of the lambs (P &lt; 0.05), but did not show a significant effect on any of the other indexes.

The role of duel hydrolysis of soybean on functional properties and protein digestibility: a sustainable approach.

Protein hydrolysates derived from food sources contains enormous number of peptides which are composed of amino acid possessess various bioactive properties. However, the use of protein hydrolysates as a nutraceutical is hindered due to their unpleasant flavour. The study aims to enhance the biological activity and palatability of protein hydrolysates. In the present study, soybean protein hydrolysate (SPH) was prepared using alcalase for 4 h (control). Modification of hydrolysis (MPH) was carried out by reiterating the hydrolysis of the supernatant obtained after 2 h of hydrolysis using an enzyme to 50% of alcalase during each successive hydrolysis. Samples were characterised by their physio-chemical and functional properties. Furthermore, the effect of modification on the protein digestibility and bitterness intensity using e-tongue was studied. The suppressive effect on retrogradation of corn starch was analysed using texture profile analysis. The results demonstrated increased protein content by 1.6 and 1.9% in MPH compared to SPH and UNH, respectively. MPH showed 1.5- and 1.6-fold higher DH% than SPH before and after gastrointestinal digestion (p < 0.05). A decrease in molecular weight was found in the order of UNH > SPH > MPH. Nevertheless, MPH displayed significantly higher functional properties (p ≤ 0.05). The hardness of retrograded corn starch was significantly reduced in the MPH (1.21N) than SPH (1.55 N) and UNH (1.81N) compared to control (1.71N) during 7-day storage at 4°C (p ≤ 0.05). E-tongue analysis of MPH showed a 4-fold reduction in bitterness than SPH. Modification of hydrolysis of soybean has demonstrated its significance in improved DH% functional properties and palatability. In addition, improved protein digestibility with promising benefits in deferral action on retrogradation of starch over the traditional process of hydrolysis was observed. The outcome of this study contributes to the potential utilisation of MPH as an ingredient in the formulation of nutraceutical products.

Interactions of White Mugwort (Artemisia lactiflora Wall.) Extract with Food Ingredients during In Vitro Gastrointestinal Digestion and Their Impact on Bioaccessibility of Polyphenols in Various Model Systems.

The bioaccessibility of phytochemicals is an important factor for new functional food design. The interaction of white mugwort extract (FE) and food ingredients (coconut oil, egg white albumen, brown rice powder, inulin, and mixtures thereof) was determined after in vitro digestion to inform the development of a functional soup for an aging population. Coconut oil exerted a protective effect on polyphenols, showing the highest bioaccessibility (62.9%) and antioxidant activity after intestinal digestion (DPPH 12.38 mg GAE/g DW, FRAP 0.88 mol Fe(ll)/g DW). In contrast, egg white albumen had the most significant negative effect on the polyphenol stability, resulting in the lowest bioaccessibility (12.49%). Moreover, FE promoted the emulsion stability and delayed starch digestion by inhibiting amylase activity via non-specific polyphenol-protein interactions, resulting in a decrease in the total reducing sugars (TRS) released during digestion. It also limited the protein digestion, probably due to the complex formation of polyphenols and proteins, consequently reducing the bioaccessibility of both amino acids and polyphenols. These findings provide useful information for designing functional food products that could promote the bioaccessibility and bioactivity of natural extracts.

Dehydrated Brewery Residue (DBR) can reduce the cost of rabbit production in Brazil, but affects performance, blood nutrients, and carcass characteristics

The study aimed to determine the chemical composition, apparent digestibility of dry matter, energy, and nutrients of Dehydrated Brewery Residue (DBR) for New Zealand White rabbits, as well as evaluate performance, biochemical and immunological blood parameters, carcass characteristics, and meat quality. Two experiments were carried out: digestibility and performance, both in a completely randomized design. In the digestibility experiment, 20 animals of mixed sexes were used, from 45 to 60 days of age, which consumed reference feed (RF) or test feed (TF - 70% RF + 30% DBR). In the performance experiment, 50 mixed-sex animals were used from 31 to 70 days of age. For digestibility, bromatological analyses were made of total dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), mineral matter (MM), organic matter (OM), calcium (Ca), phosphorus (P), gross energy (GE), hemicellulose, cellulose and lignin from samples of feces, feed (RF and TF) and experimental feed (DBR). In terms of performance, the treatments were the basal feed (BF) + four TF, made up of increasing levels of DBR inclusion (10, 20, 30, and 40%). Overall, the apparent digestibility coefficient (ADC) of DM was 64.68 ±7.91%, while the ADC of GE and CP were 67.39 ±7.79% and 80.64 ±8.99%, respectively, resulting in digestible energy and digestible protein contents of 3,081 ±356 kcal/kg and 17.97 ±2.00%. There was a linear reduction (P&lt;0.05) in the final weight, daily weight gain, and daily feed intake, but there was a linear reduction in production costs (P&lt;0.05) for both the 31- to 50-day phase and the 31- to 70-day phase. Circulating levels of calcium (P=0.013) and phosphorus (P=0.019) responded in a linear decreasing pattern to the experimental feeds. The same response was observed for slaughter weight, hot and cold carcass weight, yield of skin, head, commercial cuts, and relative weight of edible organs, as well as meat quality, in which the loss of water on thawing (P=0.004) and shear force (P=0.005) indicated less juiciness and less tenderness in the meat. Levels of 10 to 40% DBR in feed for rabbits from 31 to 70 days of age mitigate production costs, but result in a worsening of performance and reduce circulating levels of calcium and phosphorus, reduce carcass weight, commercial cuts, and edible organs, as well as increasing water loss on thawing, and reducing meat tenderness.

Evaluation of green kiwifruit juice extract on physicochemical properties, antioxidant activity, and tenderness of beef M. semitendinosus with in vitro digestion.

This study focused on the physicochemical properties and tenderness of vacuum-packaged beef M. semitendinosus as affected by various dilution ratios (DRs, 1:4, 1:2, and 1:1) of green kiwifruit juice extract (GKJE) with phosphate buffer during storage at 4°C for 7 days. In addition, the formation of peptides with antioxidant activity for GKJE ability to hydrolyze proteins present in beef was evaluated at different steps of in vitro digestion. Beef with GKJE showed higher tenderness than control (CTL, beef with brine solution alone) during storage, and the increased DR increased tenderness as compared to lower DRs. The addition of GKJE increased protein digestibility during in vitro digestion. To increase the antioxidant activity in the body, GKJE having a DR of 1:2 and 1:1 should be applied to the beef muscle with effective antioxidant activity. These results suggest that DRs of phosphate buffer and kiwifruit juice of 1:1 and 1:2 have the potential to be used as a meat-tenderizing agent and could increase the digestibility of meat as well as the antioxidant capability of bioactive peptides. PRACTICAL APPLICATION: The dilution ratio of kiwi juice with phosphate buffer at 1:1 has the potential to be used as a meat-tenderizing agent during refrigerated storage and also increase the digestibility of beef.

Designing calcium-fortified milk for improving stability and calcium bioaccessibility by solid dispersion emulsification

Approximately 70 % of the calcium intake in the adult diet worldwide is derived from dairy products. However, insoluble calcium salts, which are usually added directly during dairy production, have poor suspension stability and are prone to precipitation. The current study aimed to address the constraints of conventional production methods by utilizing solid dispersion emulsification technology to inhibit the aggregation of calcium salts. Calcium-fortified milk samples with different calcium content were prepared and compared with the commercial calcium-fortified milk, and their physicochemical, microstructural, and digestive properties were characterized. The results of this study demonstrated that all the prepared calcium-fortified milk samples exhibited a particle size of approximately 270 nm and a zeta-potential of approximately −40 mV. The calcium-fortified milk, which has been produced using solid dispersed emulsion technology, has been found to have 1.8 times more physical stability than commercial milk. Microstructural studies showed that aggregation of milk with more than 225 mg/100 mL calcium content occurred. During in-vitro digestion, it was found that the increasing calcium loading did not impact protein digestion without the creation of new fragments in the calcium-fortified milk. Calcium bioaccessibility was enhanced by approximately 50 % in comparison with the commercial product. While the release of free fatty acids was found to decrease with increasing calcium content. This study facilitates the development and utilization of calcium-fortified and low-fat foods and provides a new idea for the addition of milk minerals in dairy products.

Underlying mechanisms of different polysaccharides on the texture characteristics and protein digestibility of soybean curd

This study aimed to investigate the effects of the addition of potato starch (PS) and guar gum (GG) at different concentrations (0.4 and 0.8%) on the physical properties, protein conformation, and in vitro digestibility of soybean curd. The results indicated that the PS acted as a filler in the protein structure, enhancing the firmness, springiness, and chewiness of the soybean curd. GG encapsulated the disorganized filamentous protein matrix, increasing the adhesiveness of the soybean curd. The addition of GG and PS reduced the hydrophobic interactions and disulfide bonds responsible for cross-linking soybean curd proteins, while forming more hydrogen bonds with the proteins (p < 0.05). GG formed the most hydrogen bonds with the proteins, as well as reduced β-sheet content and transformed into more random coil and β-turn (p < 0.05). Also, the addition of GG (particularly at 0.8%) significantly reduced the degree of protein hydrolysis (31.98%) in soybean curd, resulting in fewer small molecular weight peptides and lower total amino acid content (3386.79 μg/g protein) at the end of in vitro digestion (p < 0.05). In contrast, the addition of a small amount of PS (0.4%) did not affect the protein digestibility of soybean curd. This study clarified the impact of polysaccharide additions on modifying the soybean curd texture and protein digestibility.

Fishery wastes as feed additive for the red claw crayfish Cherax quadricarinatus: Impact on growth, biochemical composition, and digestive activity

One of the challenges in aquaculture is reducing the use of fishmeal to alleviate pressure on aquatic ecosystems while maintaining protein quality and digestibility. A promising approach is the supplementation of diets with exogenous enzymes, a strategy widely used in aquaculture nutrition but scarcely explored in crustaceans. This study aimed to evaluate the effects of a diet composed of 65 % plant-based and 25 % animal-based ingredients, supplemented with a multienzyme extract derived from discards of the native Argentine shrimp Pleoticus muelleri, on juveniles of the red claw crayfish, Cherax quadricarinatus. Growth performance, endogenous digestive enzyme activities, and biochemical reserves (proteins, lipids, and glycogen) in hepatopancreas and pleon muscle were analyzed. Sixty-two crayfish weighting ⁓1.5 g were assigned to one of the following treatments: a control diet (C) or a diet supplemented with multienzyme extract (E). Crayfish were individually housed under optimal growing conditions and fed daily 3 % of their body mass; deaths and molts were recorded throughout the experiment. At day 45, fifteen replicates from each treatment were selected, weighed, anesthetized, and sacrificed. The hepatopancreas and pleon were dissected and weighed for biochemical analysis and assessment of digestive enzyme activity. The remaining replicates were subjected to the same procedure at the end of the experiment (day 90). Results showed that endogenous digestive enzymes were modulated by the multienzyme extract. Juveniles fed diet E significantly increased the specific activity of endogenous digestive peptidases and showed a trend of increasing lipases. The multienzyme extract also promoted lipid accumulation in hepatopancreas, increased glycogen in muscle, and reduced protein content in both tissues. These metabolic changes did not improve growth, as no significant differences in final weight were observed between treatments. The results highlight the need to analyze the synergy between varying concentrations of the multienzyme extract and endogenous enzymes within different protein: lipid ratios in diets, to enhance the digestive potential of crayfish and to improve growth.

Socially Acceptable Feed Formulations May Impact the Voluntary Feed Intake and Growth, but Not Robustness of Nile Tilapia (Oreochromis niloticus)

Society is becoming more demanding with aquaculture’s environmental footprint and animal wellbeing. In order to potentially mitigate these concerns, feed formulations could be based on eco-efficient (circular economy-driven) or organic ingredients. This study aimed to investigate the growth performance, feed utilization, and health status of juvenile Nile tilapia (Oreochromis niloticus) when fed with such feeds. The growth trial lasted for 8 weeks, and fish had an initial weight of 31.0 ± 0.5 g (mean ± SD). Fish were fed until visual satiation, in quadruplicate, with one of three isonitrogenous and isoenergetic experimental feeds: a commercial-like feed without fishmeal (PD), a diet based on ingredients compatible with organic certification (ORG), or a feed formulated using circular economy-driven subproducts and emergent ingredients (ECO). Fish fed ECO showed a tendency for decreased feed intake, while ORG fish significantly reduced their intake compared to those fed PD. Consequently, fish fed ECO (62.7 ± 5.4 g) exhibited almost half the growth than those fed PD (107.8 ± 6.1 g), while ORG fish almost did not increase their weight (32.7 ± 1.3 g). ECO and ORG diets had a lower digestibility for protein, lipid, and energy when compared to PD. Feed utilization of fish fed ECO or ORG was also lower than those fed PD. From the health-related genes analyzed, only glutathione reductase (gsr) showed statistically significant differences, being more expressed in fish-fed ECO than those fed PD. Thus, even when such novel formulations induced extreme effects on voluntary feed intake, their impact was noted only in fish growth, but not in robustness.

Pea protein – gum Arabic gel addition as ingredient to increase protein, fiber and decrease lipid content in muffins without impair the texture and intestinal microbiota

This study evaluated the use of a protein-polysaccharide gel (PGEL) as a muffin ingredient, and its effect on the nutritional, textural, and gut microbiome profiles. PGEL was generated by complex coacervation with Pea protein and Gum Arabic. A mixture design was performed with different flour, lipids, and PGEL proportions, where Tx9 (26 % PGEL) showed improved physicochemical characteristics. Optimization was performed using 3 variables, hardness, protein content, and in vitro protein digestibility, to generate an optimal muffin with PGEL (PGEL-Muffin). PGEL-Muffin had a positive effect in its nutritional content and texture (protein: 12.03 %, fiber: 7.90 %, lipids: 9.23 %, and hardness: 4.41 N) compared to a muffin without protein addition (Control) and a muffin with added pea protein powder (Powder-Muffin). PGEL-Muffin did not modify gut microbiome using an ex-vivo system after 4-days of administration. PGEL ingredient could be an opportunity to develop nutritionally improved products without a negative impact on textural properties.

Current Challenges of Vaccination in Fish Health Management.

Vaccination is an essential method of immunological preventive care required for the health management of all animals, including fish. More particularly, immunization is necessary for in-land aquaculture to manage diseases in fish broodstocks and healthy seed production. According to the latest statistics in 2020, 90.3 million tons of capture fishery production was achieved from the aquaculture sector. Out of the above, 78.8 million tons were from marine water aquaculture sectors, and 11.5 million tons were from inland water aquaculture sectors. About a 4% decline in fish production was achieved in 2020 in comparison to 2018 from inland aquaculture sectors. On the other hand, the digestive protein content, healthy fats, and nutritional values of fish products are comparatively more affordable than in other meat sources. In 2014, about 10% of aquatic cultured animals were lost (costing global annual losses > USD 10 billion) due to infectious diseases. Therefore, vaccination in fish, especially in broodstocks, is one of the essential approaches to stop such losses in the aquaculture sector. Fish vaccines consist of whole-killed pathogens, protein subunits, recombinant proteins, DNA, or live-attenuated vaccines. Challenges persist in the adaption of vaccination in the aquaculture sector, the route of administration, the use of effective adjuvants, and, most importantly, the lack of effective results. The use of autogenous vaccines; vaccination via intramuscular, intraperitoneal, or oral routes; and, most importantly, adding vaccines in feed using top dressing methods or as a constituent in fish feed are now emerging. These methods will lower the risk of using antibiotics in cultured water by reducing environmental contamination.