Protein Digestibility Research Articles

Dielectric barrier discharge cold plasma alleviated the immunoreactivity of egg white proteins with improved digestibility and functional properties

With the increasing number of children allergic to egg worldwide, there is an urgent need to develop strategies for effectively utilizing egg protein. As a novel food processing that can effectively reduce allergenicity and enhance protein quality and functional properties, cold plasma (CP) is gaining attention. The study investigated the impacts of the dielectric barrier discharge CP on the immunoreactivity, in vitro digestibility, functional properties, and structural changes of egg white protein (EWP). The results showed that the EWP treated with CP for 30 min had a significant decrease in immunoglobulin (IgG)-binding capacity by approximately 20% and improved in vitro digestibility. Further studies demonstrated that the decrease in the IgG-binding capacity of EWP correlated well with the alterations in the secondary and tertiary structures. The content of α-helix was decreased by 6.5% and the surface hydrophobicity increased by 2.5 folds after the 30-min treatment, compared with the untreated samples. The oxidation of peptide amino groups induces structural changes, accompanied by the oxidation of amino acid residues. This phenomenon has been validated through surface hydrophobicity and multispectral analysis. Additionally, CP also improved the foaming and emulsifying capacity of EWP by 140% and 8.03%, respectively. These findings suggest that CP treatment could be served as a potential technology to reduce the immunoreactivity, and improve the in vitro digestibility and functionality of EWP.

Co-fermentation of hot-pressed rapeseed meal with multiple strains and cellulase: Evaluating changes in protein quality and metabolite profiles

Hot-pressed rapeseed meal (RSM) is rich in resources, but high fiber content and low protein utilization result from high temperature processing. This study aims to obtain a high-quality protein source through the fermentation of hot-pressed RSM. We used Plackett-Burman and Box-Behnken designs to optimize parameters for solid state fermentation with Bacillus subtilis strain 5, Saccharomyces cerevisiae, and Aspergillus niger. Under the optimum conditions, the synergistic fermentation with multiple strains and cellulase significantly reduced anti-nutritional factors in hot-pressed RSM, while also increasing protein solubility, digestibility and extraction rate by 466.80%, 45.56% and 816.44%, respectively. 77 enzymes secreted by fermentation strains were identified in fermented hot-pressed RSM, which were mainly involved in the metabolism of proteins, peptides and amino acids (28.6%), energy (28.5%), carbohydrates (13.0%) and lipids (5.2%). Non-targeted metabonomics identified 1245 differential metabolites, with the top five being peptides and amino acids, lipids, heterocyclic compounds, alkaloids, and organic acids. These differential metabolites enhanced the nutritional, functional and flavor properties of fermented hot-pressed RSM. Among them, 702 differential metabolites were enriched into metabolic pathways, with the largest number of pathways associated with amino acid metabolism. These results hold important implications for understanding the quality of fermented hot pressed RSM.

Modulating the techno-functional properties of quinoa (Chenopodium quinoa Wild) protein concentrate using high-pressure technologies and their impact on in vitro digestibility: A comparative study

High hydrostatic pressure (HHP; 200–600 MPa at 24 °C for 20 min) and dynamic high pressure (DHP; 50–180 MPa) were applied to modulate the techno-functional properties of quinoa protein concentrate (QPC) produced from non-defatted flour using a lab-scale extraction. QPC's unique composition, with 74.6 % protein and significant levels of unsaturated fatty acids, influenced the effects of HHP and DHP. HHP significantly (P < 0.05) enhanced hydration properties, peaking at 400 and 500 MPa (on average 4.34 g/g), while DHP reduced the oil absorption capacity from 2.5 to 1.8 g/g. Both processing techniques decreased QPC protein solubility. This reduction corresponded to decreased foaming capacity and emulsifying properties in HHP-processed QPC. DHP increased emulsifying activity and stability indices, with optimized improvements at 100 MPa of 39.4 and 414.4 %, respectively. These modifications in QPC's properties occurred without noticeable loss in in vitro protein digestibility (IVPDaverage = 86.1 %). The findings support the potential of high-pressure technologies to uniquely modulate different techno-functional properties of QPC, produced from non-defatted flour, while maintaining high digestibility, thereby offering greater versatility in its use. Industrial relevanceQuinoa is a strategic choice for diversifying plant protein sources, with the use of non-defatted flour in QPC production offering new insights into its composition and properties, reducing both costs and environmental impact. In this study, HHP and DHP, recognized as “green” physical processing technologies, demonstrated advantageous potential to develop innovative quinoa protein ingredients with added value and clean-label appeal, while maintaining their high nutritional value. The distinctive effects of high-pressure technologies and varying pressure levels on modulating QPC's techno-functional properties underscore the creation of multifunctional QPC and the optimization of key properties, addressing the urgent demands of the plant-based food segment.

Exploring the nutritional and biological properties of green coffee extracts: A comparative study of aqueous and enzymatic extraction processes

The effects of aqueous (AEP) and enzyme-assisted aqueous extraction processes (EAEP) on the biological and nutritional properties of green coffee extracts (protein and antioxidant-rich fraction) were investigated. All extracts exhibited high in vitro protein digestibility (>98%), regardless of the pH and use of enzymes during extraction, probably due to the low molecular weight of coffee proteins. Raising extraction pH from 7.0 to 9.0 resulted in extracts with lower concentrations of caffeine and some phenolic compounds such as chlorogenic and cinnamic acids, as well as catechin and epicatechin. This led to a reduction in the antioxidant activity of the extracts obtained at alkaline pH (AEP – pH 9.0). Overall, higher phenolic and caffeine extractability was achieved at neutral pH (AEP – pH 7.0), with no observed improvement in extraction yields when carbohydrases and/or proteases were employed. Coffee extracts generated by AEP at pH 7.0 exhibited the highest lipase inhibitory activity (66%), primarily attributed to their higher chlorogenic acid concentration. Conversely, EAEP extracts exhibited higher angiotensin-converting enzyme inhibition (up to 85%) compared to AEP extracts (68.5 – 74.3%). This strong inhibitory activity is likely related to the presence of both phenolic compounds (mainly chlorogenic acid) and smaller peptides. Nevertheless, all extracts exhibited low effectiveness for α-glucosidase inhibition (≤14%) and antimicrobial activity against S. aureus and E. coli. The current research underscores the feasibility of modulating the composition of green coffee extracts using sustainable and scalable AEP and EAEP, paving the way for developing tailored extracts with specific biological properties.

Chemical Composition and In Vitro Protein Digestibility of Duckweed and Feed Ingredients

Duckweed is an aquatic floating plant with the potential to be used as animal feed due to its richness in protein, amino acids, starch, vitamin and minerals. Furthermore, duckweed has a high growth rate and reproducibility. Therefore, this research aimed to determine the chemical composition and in vitro protein digestibility of duckweed (Lemna, Wolffia and Spirodela) in comparison to other feed ingredients. The chemical composition was determined through proximate analysis including dry matter (DM), crude protein (CP), ether extract (EE), crude fiber (CF), ash and nitrogen free extract. The in vitro protein digestibility procedure simulates conditions similar to those in the swine digestive tract using synthetic enzymes to control pH, temperature and digestion time. In the results of chemical composition, Lemna and Wolffia were classified as protein sources, with high CP content (221.87 and 442.65 g/kg DM, respectively) and low CF content (63.30 and 109.11 g/kg DM), whereas Spirodela had low CP content (179.64 g/kg DM) and CF content (170.57 g/kg DM). The EE content in duckweed amounted to 16.74, 46.23 and 52.47 g/kg DM for Wolffia, Spirodela and Lemna, respectively. Additionally, high ash content was observed in Spirodela (212.40 g/kg DM), Wolffia (149.34 g/kg DM) and Lemna (142.06). For standardized ileal digestibility (SIDCP), the SIDCP of all feed ingredients were within the range of 32 to 96 %. With regard to duckweed, Lemna (72 %) showed significantly higher (p &lt; 0.05) SIDCP compared to Wolffia (69 %) and Spirodela (39 %) due to the low contents of CF and ash. Based on nutritional values, Lemna and Wolffia were grouped with corn DDGS and brewer’s grain, indicating their potential as animal feed for sustainable livestock production. HIGHLIGHTS Duckweed exhibited high protein content, ranging from 179.64 to 65 g/kg dry matter. For in vitro protein digestibility, Lemna and Wolffia had high true digestibility, amounting to 79 and 75 %, respectively. Based on nutritional values, Lemna and Wolffia were grouped with corn DDGS and brewer’s grain, indicating their potential as animal feed for sustainable livestock production. GRAPHICAL ABSTRACT

A comparison of animal and plant-based proteins from an economic, environmental, and nutritional perspective in the Republic of Ireland

CONTEXTProtein is a central component of health and nutrition. The current protein production system is unlikely to sustainably meet the growing global demand for protein. Therefore, alternative sources of protein must be considered. OBJECTIVEThis study uniquely compares animal-based (milk, beef meat, sheep meat) and plant-based (cereals and legumes) protein production in terms of land usage. The comparison is carried out across a suite of economic, environmental, and nutritional metrics. As land use decisions are taken at the farm level, the analysis adopts a farm gate approach. Focusing on the supply side, consumption is not considered in the analysis. METHODSEconomic performance is measured through the gross and net margins. Environmental performance is evaluated through farm-level greenhouse gas (GHG) emissions and nutrient (nitrogen and phosphorus) balances. Nutritional performance is measured through the gross protein yield, the protein yield corrected for digestibility and land-use efficiency, i.e., the land needed to generate one kg of (digestible) protein. Results are expressed per hectare and per 100 g of gross and digestible protein to allow for a holistic comparison. The analysis focuses on the Republic of Ireland, a relevant country given the importance of the strong agricultural export focus, the dominance of the livestock sector and the country's ambitious environmental emission reduction targets. RESULTS AND CONCLUSIONSFindings indicate that, on a per hectare basis, milk production on dairy farms has the strongest economic performance and highest GHG emissions amongst the products considered. Crops' gross and net margins are less than half that of dairy farms, but they also show the strongest environmental performance generally. Cereals and legumes have the best nutritional performance, from a protein perspective, whereas sheep meat production returned the lowest gross and digestible protein yields per hectare. Arable crops also show the lowest GHG emissions and nutrient balances on a per unit of protein basis. SIGNIFICANCELand-use policies need to be designed holistically, given the complexity of the agricultural sector. Agricultural policy design currently focuses on income support and on the environmental impact of the agricultural sector, but farmers' livelihood and food and protein security need to be safeguarded. Diversifying agricultural production and increasing plant-based protein production in Ireland, a country with a livestock-focused agricultural sector, could contribute to achieving the climate change targets of the country, provided the necessary policy levers are in place.

Changes in the biological and nutritional value of pea and bean grains as a result of their bioactivation

The relevance of the study is due to the need to improve the technology for processing peas and beans of domestic selection into plant-based drinks and their use in technologies for alternative products of complex raw materials for healthy, functional and specialized nutrition of various population groups. The purpose of the work is to study the influence of the developed technological modes of bioactivation on the nutritional and biological value, functional and technological properties of the protein-carbohydrate complex of pea and bean grains. The work examines the results of studies of changes occurring in pea grains bred at the Bashkir Research Institute of Agriculture and beans bred at the Omsk State Agrarian University during their bioactivation using the Smart Sprouter "Rosinka" installation, in particular the biochemical composition and inhibitory activity of grain of the studied varieties, a protein complex and amino acid composition, protein digestibility in vitro, functional and technological properties of the protein-carbohydrate complex of grain. The research has been carried out using generally accepted, modern instrumental methods for analyzing the properties of raw materials and finished products. It has been established that the use of the developed technological parameters of bioactivation leads to modification of the functional and technological properties of the structure-forming nutrients of grain, intensive accumulation of all amino acids, with the exception of threonine, make it possible to increase the protein content in pea grain by 15.32 % and beans by 14.96 %, relative to the initial values increase the degree of compliance of pea and bean grain protein with the FAO/WHO reference protein by 4.48 and 17.53 %, reduce the activity of grain protease inhibitors by 19.76 and 26.12 %, increase the digestibility of grain protein by 7.77 and 5.85 %. The research results prove the feasibility of using bioactivated pea and bean grains for the production of alternative products with a complex raw material composition, including plant-based drinks and products in the "dairy alternatives" segment.

Investigating the chemical composition, digestion and fermentation of Alternanthera sessilis red plant and its effect on the performance of fattening lambs.

The present experiment was conducted to evaluate the nutritional value of red Alternanthera sessilis for fattening lambs when they were replaced with alfalfa forage. Forty growing lambs with an average weight of 21.12kg and an age of 5 months were randomly assigned to four experimental treatments. Growth performance, nutrient digestibility, rumen fermentation parameters, protozoa population, blood parameters, and composition of carcass components were evaluated. The results of this experiment showed that the use of Alternanthera sessilis in the diet significantly reduced feed intake, increased the average daily weight gain, and improved the feed conversion ratio compared to the control treatment (P < 0.05). The digestibility of dry matter and protein was significantly increased (P < 0.05), while the digestibility of neutral detergent fiber, acid detergent fiber, and organic matter showed a numerical increase. Diets containing different levels of the Alternanthera sessilis plant did not affect pH, but the increase in the amount of this plant in the diet led to an increase ammonia nitrogen concentration and rumen protozoa population (P < 0.05). The addition of Alternanthera sessilis to the diet significantly reduced the concentration of blood glucose and cholesterol and increased the concentration of blood urea nitrogen (P < 0.05). Except for the weight of the thigh and neck, the effect of experimental treatments on other carcass components was not significant. Overall, the results of this experiment showed that using the Alternanthera sessilis plant in the rations of fattened lambs as a substitute for alfalfa forage not only had no negative effect on the studied parameters but also improved them in some cases. Therefore, Alternanthera sessilis can be used in rations of fattened lambs as a substitute for part of alfalfa forage.

Effect of supplementation of cactus (Opuntia ficus-indica) cladodes, Acacia saligna, wheat bran and cotton seed cake on feed intake, digestibility, growth and carcass characteristics of goats

The objective of this study was to evaluate the effect of supplementation of cactus (Opuntia ficus-indica) cladodes, Acacia saligna, wheat bran and cotton seed cake on growth, digestibility, intake and carcass characteristics of goats. A randomized complete block design was used in the experiment with 24 yearling central highland goats with an initial body weight of 15.6 - 16.1kg. The same amount of grass hay (GH) + 150 gDM/head/day wheat bran (WB) was given to all animals. The experimental diets consisted of 80 cotton seed cake (CSC) as treatment 1 (T1), 45CSC +160 cactus cladodes (CC) as T2, 45CSC+ 80 Acacia saligna (AS) as T3, and 45CSC+80CC+40AS as T4 (gram dry matter: DM, per day per goat), Data were gathered on the goats' growth, digestibility, intake, and carcass of major organs, edible and nonedible organs. The consumption of dry matter and organic matter was higher in goats fed T2 and T4 than in the T1 group. The DM, organic matter (OM) and crude protein (CP) digestibility, average daily body weight gain and feed conversion efficiency were higher in T4 and T3 goats when compared to T2 goats. Goats fed on T4 had higher hot carcass weight and dressing percentage on slaughter body weight basis than T2, T3, and T1 supplemented goats. Generally, the experimental diets improved goats’ performance in descending order (T4 &gt; T3 &gt;T1 &gt;T2). Supplementation of T4 (replacement of 35 g DM of cotton seed cake per day by 40g of Acacia saligna and 80g of cactus cladodes on dry matter bases) could be recommended to improve goat performance.

Productivity and nitrogen metabolism of lactating cows fed pistachio hull with soybean meal partially replaced by slow-release urea.

Pistachio hull (PH), a rich source of tannin, may interact with nitrogen (N) and affect N metabolism in dairy cows. This investigation aimed to assess the effects of feeding PH and two N sources (soybean meal: SBM or slow-release urea: SRU) on milk production, digestibility, and N metabolism in lactating dairy cows. The study utilized a 4 × 4 Latin square design with 12 Holstein dairy cows (body weight = 611 ± 39kg; 84 ± 14 days in milk; 45.6 ± 5.3kg/d milk), with treatments arranged in a 2 × 2 factorial configuration. The main factors were (1) the tannin source [without or with dried PH included at 76.5g/kg of diet DM] and (2) two N sources [SBM vs. SRU]. Crude protein and total phenolic and tannin contents were greater, but NDF was lower in PH than in sugar beet pulp. Feeding diets containing 7.65% PH resulted in reductions in milk yield, milk urea N, and milk efficiency but milk fat and protein concentration increased. Milk yield was similar between SBM and SRU. Feeding PH in replacement to sugar beet pulp did not interact with N sources, except for feed intake, as the PH + SRU diet tended to decrease feed intake (P = 0.09). Feeding PH was also associated with decreased dry matter, crude protein, and NDF digestibility. Dry matter digestibility decreased when a portion of SBM was replaced by SRU. Feeding PH in replacement to sugar beet pulp lowered ruminal ammonia-N concentration and increased acetate-to-propionate proportion. Feeding PH vs. sugar beet pulp had no effect on N intake and N excretion in urine and milk, but it increased the amount of N excretion in feces and decreased apparent N efficiency (milk N/N intake). Alanine aminotransferase was lower in cows fed SRU only in PH- but not sugar beet pulp-containing diets. Blood creatinine was lower when SRU was included in the PH-containing diet, but the opposite was observed in diets containing sugar beet pulp. Feeding PH instead of sugar beet pulp did not affect blood urea-N but resulted in lower glucose and aspartate aminotransferase concentrations. Overall, cows fed PH in replacement to sugar beet pulp were less efficient in converting feed nutrients into milk production, likely because of its negative effect on nutrient digestion. Partial replacement of SBM with SRU had no influence on lactation productivity and urea-N concentration in milk and blood. This may imply the suitability of SRU in providing a sustained supply of N in the rumen, likely qualifying it as a viable source of N to replace a portion of SBM in dairy diets.

The revelance of the development of new reciples of protein-vitaminized products for sports nutrition in Kazakhstan (in Kazakh language)

The specificity of sports nutrition lies in the fact that a person uses various carbohydrate, protein and vegetable drinks to restore the body after physical activity. Currently, in the sports nutrition market of the CIS countries, including our country, products from other countries account for more than 95%. Because of this, the prices of sports products are very expensive. Therefore, the development of sports nutrition products containing highly digestible protein products for the body based on plant raw materials is very relevant. At the same time, the development of these products based on legumes, in particular, their peas and soybeans, is the most acceptable. In addition, pea protein can be used to build muscle mass - due to the high level of L-arginine contained in it, the protein stimulates the secretion of human growth hormone, which is involved in the regulation of growth, metabolism and muscle mass. This article presents materials on the relevance of the development of new formulations of protein - fortified products for sports nutrition in Kazakhstan.

Impact of phosphorus fertilization on the yield and quality of various Alfalfa (Medicago sativa L.) varieties in light chestnut soils

This study investigates the impact of phosphorus fertilization on the yield and quality of various alfalfa (Medicago sativa L.) varieties grown in light chestnut soils. Conducted over a three-year period from 2013 to 2015, the research was carried out in the Karasay district of the Almaty region under irrigated conditions. The experiment included six alfalfa varieties: NS Alfa, VS Banat, Mediana, Nera, Niagara, and Kokoray. Four phosphorus treatments were applied: control (no phosphorus), 60 kg/ha (P60), 90 kg/ha (P90), and 120 kg/ha (P120), using double superphosphate as the phosphorus source. The results demonstrated that phosphorus fertilization significantly enhanced both the yield and quality of alfalfa. Across all varieties, the highest yield was observed with the application of 120 kg/ha phosphorus. For instance, NS Alfa's yield increased from 283.3 c/ha in the control to 349.7 c/ha with P120, reflecting a 23% increase. Similarly, VS Banat and Mediana exhibited yield increases of 23% and 25%, respectively, at the highest phosphorus level. The study also revealed improvements in the nutritional quality of alfalfa hay. Crude protein content increased from 20.3% to 22.0% in NS Alfa, while digestible protein content rose from 11.20% to 12.40%. Other quality parameters, including fat and carotene content, also improved significantly with higher phosphorus levels. Moreover, the availability of nitrate nitrogen and mobile phosphorus in the soil increased progressively with higher phosphorus application rates, contributing to better nutrient uptake and overall plant health. This research underscores the importance of phosphorus fertilization in maximizing alfalfa yield and quality. The findings suggest that the optimal phosphorus application rate for enhancing alfalfa production in light chestnut soils is 120 kg/ha, providing valuable insights for sustainable agricultural practices in similar agro-ecological zones.

Bacillus amyloliquefaciens CU33 Fermented Feather–Soybean Meal Product Improves the Crude Protein Digestibility, Diarrhea Status, and Growth Performance of Goat Kids

This study investigates the effects of replacing fish meal with fermented feather meal–soybean meal product (FFSMP) from Bacillus amyloliquefaciens CU33 in the starter on growth performance, relative health performance, and digestibility of Alpine goat kids. In trial 1, thirty-two Alpine goat kids (male) were randomly assigned to dietary supplementation of 2% feather meal–soybean meal mix (FSM), 2% fish meal, or replacing fish meal with 50% or 100% FFSMP (FFSMP-50 or FFSMP-100) in starter (n = 8). In trial 2, sixteen goat kids were selected after trial 1 and used in this digestion trial which began from 12 weeks old. The treatments were the same as in trial 1 (n = 4). In trial 1, the growth performance of the FFSMP groups was better than the FSM group at 0 to 10 weeks (p &lt; 0.05). The fecal consistency index of the FFSMP-100 group was better than the FSM group at 0 to 5 weeks and 5 to 10 weeks. In trial 2, the crude protein (CP) digestibility of the FSM group decreased (p &lt; 0.05). In conclusion, dietary supplementation with 2% FFSMP in goat kids’ diets can improve the growth performance, the CP digestibility, and diarrhea status, and it can completely replace the fish meal in starter diets.

Amelioration of tiger nut insoluble dietary fiber as a partial substitute for fat in meat emulsions: Techno-functional properties and in vitro protein digestibility

The effects of tiger nut insoluble dietary fiber (TNF) (1%-3% w/w) on techno-functional properties and in vitro protein digestibility of low-fat meat emulsions were examined. The results showed that TNF (especially 2% and 3%) could improve techno-functional performances of low-fat meat emulsions in terms of water binding capacity and textural attributes, which were even preferable to the high-fat control. The improvements were associated with the attenuated fluidity of inner water within the gels, the increased storage modulus (G′), the formation of a well-joined gel network with uniformly-dispersed fat particles and the uncoiling of α-helix and the formation of β-sheet. The weakened water mobility, the heat-triggered conformational shift from α-helix to β-sheet, as well as less and evenly distributed fat particles ulteriorly led to elevated protein digestibility in meat emulsions. Therefore, TNF shows promise as a fat substitute to develop fat-reduced emulsified pork meat products with desirable quality and digestion behaviors.

Fermented but Not Irradiated Cottonseed Meal Has the Potential to Partially Substitute Soybean Meal in Broiler Chickens.

This study was conducted to investigate and compare the effects of substituting soybean meal (SBM) with untreated cottonseed meal (CSM), fermented CSM (FCSM), or electron beam-irradiated CSM (ICSM) on the growth performance, cecal microbiota, digestive enzyme activity, apparent ileal digestibility (AID), and excreta gas emission of broiler chickens. A total of 384 one-day-old male broiler chickens were randomly assigned to four experimental diets, with eight replicates per diet and 12 birds per replicate, for six weeks. The experimental diets consisted of a control diet based on corn-SBM and three other diets in which 50% of the SBM (control) was substituted with CSM in its raw, irradiated, and fermented forms. The results showed that throughout the entire rearing period, feeding broiler chickens with ICSM significantly increased average daily gain (ADG) and body weight (BW) compared to the CSM diet (p < 0.05). Replacing 50% of SBM with FCSM led to a significant improvement in BW, ADG, and feed conversion ratio (FCR) compared to the CSM and ICSM diets (p < 0.05). Interestingly, no significant differences in BW, ADG, or FCR were observed between birds fed FCSM and those on the control diet (p > 0.05). Birds fed FCSM diets exhibited the lowest pH value in the crop, ileum, and ceca. Substituting SBM with FCSM significantly reduced Escherichia coli and Clostridium spp. counts in the ceca, while enhancing the presence of Lactobacillus spp. (p < 0.05). The AID of protein and ether extract was higher in the FCSM group than in the CSM and ICSM groups (p < 0.05). Compared to the CSM diet, ICSM feeding improved protein digestibility (p < 0.05). Broiler chickens on the FCSM diet exhibited higher intestinal amylase and protease activity than those on the other diets (p < 0.05). Furthermore, feeding diets containing FCSM significantly reduced ammonia emissions compared to the other diets (p < 0.05). Overall, our results indicated that microbial fermentation of CSM is a more effective approach than irradiation for enhancing the nutritional value of CSM. Therefore, FCSM is recommended as a viable alternative protein source that can safely replace up to 50% of SBM in broiler chicken diets, particularly during times of fluctuating SBM prices and availability issues.

Intestinal microbiota composition in broilers fed protein-free or casein-based diets

Growing broiler chickens of the Cobb500 strain were used to determine the effects on intestinal microbiota composition of a protein-free (PF) diet as compared to a diet based in casein (CAS) as the only protein source. CAS was formulated to contain the same amount of protein (190 g kg-1) as a commercial Maize-soy diet which was used as a practical reference. The ileal AA flow (g kg-1 dry matter intake) was significantly higher (P < 0.001) than PF in birds fed protein containing diets (CAS or Maize-soy). Taken as a whole (discriminant and ANOSIM analysis), the intestinal (ileal and caecal contents and ileal tissue) microbiota composition of PF and CAS were significantly (P < 0.001) different from Maize-soy and not different from each other in some cases. RT-qPCR and sequencing analysis of the ileal and caecal microbiota revealed significant (P < 0.05) differences in a number of bacterial groups between broilers fed PF, CAS or Maize-soy diets. The main result was that the lack of protein in the intestinal medium of PF birds resulted in a drop of Lactobacillus spp. counts (on average, 43 in PF vs 1,734 in the Maize-soy diet) and increased Enterobacteriaceae (on average, 419 in PF vs 172 in the Maize-soy diet) and other potentially pathogenic bacterial groups (in both intestinal contents and tissue). Thus, the lack of protein in the intestinal medium of PF birds resulted in a microbiota composition compatible with a pro-inflammatory state, and this effect was somewhat less marked in birds fed CAS. The results reported here suggest that the adverse effects on microbiota composition in broilers fed CAS were less marked than in those fed PF, which would be in line with a preferential use of a highly digestible protein containing diet to determine endogenous AA excretion instead of a PF diet.

In Vitro Digestion and Fermentation of Cowpea Pod Extracts and Proteins Loaded in Ca(II)-Alginate Hydrogels.

Antioxidants derived from food by-products are known for their bioactive properties and impact on human health. However, the gastrointestinal behavior is often poor due to their degradation during digestion. The development of Ca(II)-alginate beads supplemented with biopolymers and enriched with cowpea (Vigna unguiculata) extract could represent a novel environmentally friendly technological solution to produce functional ingredients in the food industry. The present study evaluates the impact of in vitro digestion/fermentation by analyzing global antioxidant response (GAR), production of short-chain fatty acids (SCFAs) as a modulation of gut microbiota, and behavior of proton transverse relaxation times by low-field nuclear magnetic resonance (as an indicator of gelation state and characterization of microstructure). Results revealed that guar gum and cowpea protein preserved a high GAR of total phenolic compounds and antioxidant capacity by ABTS and FRAP methods after digestion/fermentation, promoting an adequate protection of the bioactives for their absorption. Alginate-based beads have great potential as prebiotics, with the guar gum-containing system contributing the most to SCFAs production. Finally, the overall higher mobility of protons observed in the intestinal phase agrees with structural changes that promote the release of phenolic compounds during this stage. Beads are excellent carriers of bioactive compounds (cowpea phenolic compounds and peptides) with potential capacities.

Nutritional evaluation of an aqueous-processed canola protein concentrate in diets of Atlantic Salmon Salmo salar at different life stages

A novel aqueous processing method was applied on canola defatted meal to produce a protein concentrate (>76 % crude protein, dry matter basis). This aqueous-processed canola protein concentrate (ACPC) was evaluated in three experiments with Atlantic salmon. The objectives were to (1) estimate the nutrient digestibility of ACPC in juvenile fish, (2) appraise its nutrient digestibility in post-smolt salmon, and (3) evaluate the long-term effect of ACPC on growth, survival, nutrient utilization, body composition, fillet pigmentation and gut histology of post-smolt salmon. In the first study, one Reference and one test diet, which was a blend of 70 % Reference and 30 % ACPC (70:30 ratio), were fed to juvenile salmon (57 ± 7 g) and feces were collected using settling columns. In the second study, post-smolt salmon (228 ± 4 g) were fed one Reference and three test diets, which consisted of three Reference to ACPC ratios: 90:10, 80:20 and 70:30. Feces were collected by manual stripping. The long-term study (168 days) was designed as a 2 × 4 full factorial analysis with two types of formula (Americas, with processed animal proteins (PAPs), and Europe, without PAPs) and four inclusion levels of ACPC (0, 10, 15, 20 %) fed to post-smolt Atlantic salmon (228 ± 5 g). Fish were bulk weighed every 28 or 56 days. Distal intestine and fillet were sampled (10 fish/tank) at the end for histological examination and color measurement, respectively. All diets (43–49 % crude protein, 18–25 % crude lipid depending on studies) were extruded and fed to apparent satiation. The apparent digestibility coefficients (ADCs) of ACPC protein in juvenile and post-smolt salmon were 89 % and ≥ 94 %, respectively. The essential amino acids ADCs in juvenile and post-smolt salmon were 83–99 % and 91–99 %, respectively. ACPC protein digestibility was not significantly affected by its inclusion level (P = 0.470). In the third experiment, growth (TGC: 0.143–0.160) and feed intake (668–780 g/fish) were not significantly affected by ACPC inclusion (P ≥ 0.10). Feed conversion ratios varied between 1.04 and 1.08. An unexpected occurrence of disease caused 1.6 % mortality over three weeks during the 24-week long-term study and survival was significantly higher in salmon fed ACPC-containing diets (P < 0.001). ACPC inclusion significantly increased fillet redness (P < 0.001) and increased villus length of distal intestine (P < 0.001). In conclusion, ACPC was a safe and nutritive protein alternative in salmon diets, regardless of inclusion level.

Determination and Prediction of Amino Acid Digestibility in Rapeseed Cake for Growing-Finishing Pigs.

The experiment was conducted to determine the apparent or standardized ileal digestibility (AID or SID) of crude protein (CP) and amino acids (AA) in 10 rapeseed cake samples fed to pigs, and to construct predictive models for the SID of CP and AA based on the chemical composition of rapeseed cakes. Twenty-two cannulated pigs (initial body weight: 39.8 ± 1.2 kg) were assigned to two 11 × 3 incomplete Latin square designs, including an N-free diet and 10 diets containing rapeseed cake. Each experimental period included 5 days of adaptation and 2 days of ileal digesta collection. Titanium dioxide (TiO2) was added at 0.3% to all the diets as an indigestible marker for calculating the ileal CP and AA digestibility. The coefficients of variation (CV) of the content of crude fat (EE), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and total glucosinolates (TGS) in 10 samples of rapeseed cake were greater than 10%. The standardized ileal digestibility (SID) of crude protein (CP), lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) in rapeseed cake was 73.34% (61.49 to 81.12%), 63.01% (41.41 to 73.10%), 69.47% (50.55 to 88.16%), 79.61% (74.41 to 87.58%), and 94.43% (91.34 to 97.20%), respectively. The best prediction equations for SIDCP, SIDLys, and SIDVal were as follows: SIDCP = 90.124 - 0.54NDF (R2 = 0.58), SIDLys = 100.107 - 1.229NDF (R2 = 0.94), and SIDVal = 151.012 - 2.990TGS (R2 = 0.57). Overall, great variation exists among the 10 rapeseed cakes, and the NDF, TGS, and heating temperature can be used as the key predictors for the SID of CP and AA.

Study on stability of rose anthocyanin extracts and physicochemical properties of complex with whey protein isolate after spray drying.

Pingyin rose is an edible flower rich in anthocyanins. In this study, antioxidant capacity and color were used as the main evaluation indexes to investigate the effects of common physical and chemical factors on the stability of rose anthocyanin extracts (RAEs). In addition, the physicochemical properties of the whey protein isolate (WPI)-RAEs complex after spray drying were studied. Vitamin C, temperature, and some metal ions can cause different degrees of discoloration of RAEs solution. More importantly, heat treatment, as well as most metal ions and sugars, had no significant effect on the antioxidant capacity of RAEs solution (p>0.05). Moreover, compared to spray-dried pure WPI, the WPI-RAEs powder was delicate and uniform, and had higher particle size, bulk density, moisture activity, and better gel properties. The release rate of all WPI-RAEs sol/gel to RAEs reached about 89% in the intestinal digestion stage, but the WPI-RAEs interaction reduced the digestibility of protein in the intestinal digestion stage. We hope that this study can provide a theoretical basis for the development and utilization of WPI-RAEs as food ingredients.