Protein hydrolysates in animal nutrition: Industrial production, bioactive peptides, and functional significance

Stability of Fly Maggot Peptides and Its Alleviating Effect on Lipopolysaccharide Combined with Hemocoagulase Oxidative Stress in Arbor Acres Chicks

Recently, there has been fast-growing interest among researchers in discovering bioactive peptides from insects and evaluating their potential applications in livestock production. The present study aimed to assess the antioxidant properties and stability of fly maggot peptide (FMP) and its effects on Arbor Acres (AA) broilers' oxidative stress induced by lipopolysaccharide (LPS) and hemocoagulase (HC). A total of 108 one-day-old AA broilers were randomly divided into six groups: CG (normal saline, basal diet), DG (LPS + HC, basal diet), VG (DG + vitamin C 50 ug/kg), LPG (DG + FMP 5 mg/kg), MPG (DG + FMP 15 mg/kg), and HPG (DG + FMP 25 mg/kg). The results showed that the addition of FMP to the diet promoted LPS+ HC-induced increases in average daily gain (ADG), total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC). Meanwhile, FMP regulated the intestinal morphology. Additionally, FMP decreased the increase in the contents of malondialdehyde (MDA), the relative weight of immune organs, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). In conclusion, this research suggested that the addition of FMP can relieve the LPS+ HC-induced oxidative stress of AA broilers and the recommended dose of FMP is 25 mg/kg. This study presents a theoretical foundation for the addition of an FMP supplement for the purpose of protecting broilers' growth.

Antihypertensive and Antidiabetic Drug Candidates from Milkfish (Chanos chanos)-Identification and Characterization through an Integrated Bioinformatic Approach

Integrated bioinformatics tools have created more efficient and robust methods to overcome in vitro challenges and have been widely utilized for the investigation of food proteins and the generation of peptide sequences. This study aimed to analyze the physicochemical properties and bioactivities of novel peptides derived from hydrolyzed milkfish (Chanos chanos) protein sequences and to discover their potential angiotensin-converting enzyme (ACE)- and dipeptidyl peptidase-4 (DPPIV)-inhibitory activities using machine learning-based tools, including BIOPEP-UWM, PeptideRanker, and the molecular docking software HADDOCK 2.4. Nine and three peptides were predicted to have ACE- and DPPIV-inhibitory activities, respectively. The DPPIV-inhibitory peptides were predicted to inhibit the compound with no known specific mode. Meanwhile, two tetrapeptides (MVWH and PPPS) were predicted to possess a competitive mode of ACE inhibition by directly binding to the tetra-coordinated Zn ion. Among all nine discovered ACE-inhibitory peptides, only the PPPS peptide satisfied the drug-likeness analysis requirements with no violations of the Lipinski rule of five and should be further investigated in vitro.

Circular bioeconomy in action: Upscaling cutlassfish waste for eco-friendly recombinant protein production

The fish processing industry generates a significant amount of waste, and the recycling of this waste is an issue of global concern. We sought to utilize the heads of cutlassfish (Trichiurus lepturus), which are typically discarded during processing, to produce peptone, which is an important source of amino acids for microbial growth and recombinant protein production. Cutlassfish head muscle (CHM) were isolated, and the optimal protease and reaction conditions for peptone production were determined. The resulting peptone contained 12.22 % total nitrogen and 3.19 % amino nitrogen, with an average molecular weight of 609 Da, indicating efficient hydrolysis of CHM. Growth assays using Escherichia coli have shown that cutlassfish head peptone (CP) supports similar or superior growth compared to other commercial peptones. In addition, when recombinant chitosanase from Bacillus subtilis and human superoxide dismutase were produced in E. coli, CP gave the highest expression levels among six commercial peptones tested. In addition, the expression levels of chitosanase and superoxide dismutase were 20 % and 32 % higher, respectively, in CP medium compared to the commonly used Luria-Bertani (LB) medium. This study demonstrates the potential of using cuttlassfish waste in the production of microbial media, thereby adding significant value to fish waste. The results contribute to sustainable waste management practices and open avenues for innovative uses of fish processing by-products in biotechnological applications.

Cottonseed meal protein hydrolysate influences growth performance, carcass characteristics, serum biochemical indices, and intestinal morphology in yellow-feather broilers

This study investigated the effects of cottonseed meal protein hydrolysate (CPH) on the growth performance, carcass characteristics, serum biochemical indices, intestinal morphology, and enzyme activities of yellow-feather broilers. We randomly divided 240 chicks into four groups, each with six replicates: a basal diet with 0% (CON), 1% (LCPH), 3% (MCPH), or 5% (HCPH) CPH. The trail spanned 63 days and included three phases: Days 1-21, 22-42, and 43-63. Increased average daily gain (ADG) and decreased ratio of feed to gain (F/G) with LCPH were observed in 21-day-old broilers (P < 0.05). MCPH led to higher ADG and average daily feed intake (ADFI) in 42-day-old broilers (P < 0.05). Additionally, CPH supplementation resulted in increased dressing percentage, percentage of half-eviscerated yield, percentage of eviscerated yield, breast muscle rate, and leg muscle rate were observed (P < 0.05) with diet. The serum levels of total protein (TP), high-density lipoprotein cholesterol (HDL-C), calcium (Ca), and phosphorus (P) were enhanced, and blood urea nitrogen (BUN) and triglyceride (TG) levels decreased with diet and CPH (P < 0.05). CPH increased the length of the jejunum and ileum and the weight of the duodenum, jejunum, and ileum in 21-day-old broilers (P < 0.05). Alterations in the duodenal villus structure in broilers occurred on Days 21 and 42, and the CPH groups performed better; however, a similar change occurred in the jejunum on Days 42 and 63 (P < 0.05). MCPH and HCPH enhanced trypsin activity in the duodenum of 21-day-old and 63-day-old broilers (p < 0.05). Chymotrypsin activity increased (P > 0.05) in the duodenum of 63-day-old broilers fed MCPH. Lipase activity increased (P < 0.05) in the jejuna of 21-day-old broilers treated with HCPH. CPH increased trypsin activity in the ilea of 21-day-old broilers (P < 0.05). These results showed that CPH influenced the growth performance, carcass characteristics, serum biochemical indices, and intestinal morphology of yellow-feather broilers, which are related to growth stage. The recommended CPH level in broilers is 1% before 21 days of age and 3% after 21 days of age.

Review of fish protein hydrolysates: production methods, antioxidant and antimicrobial activity and nanoencapsulation

Marine products have gained popularity due to their valuable components, especially protein, despite generating significant waste. Protein hydrolysates are widely recognized as the most effective method for transforming these low-value raw materials into high-value products. Fish protein hydrolysate (FPH), sourced from various aquatic wastes such as bones, scales, skin, and others, is rich in protein for value-added products. However, the hydrophobic peptides have limitations like an unpleasant taste and high solubility. Microencapsulation techniques provide a scientific approach to address these limitations and safeguard bioactive peptides. This review examines current research on FPH production methods and their antioxidant and antibacterial activities. Enzymatic hydrolysis using commercial enzymes is identified as the optimal method, and the antioxidant and antibacterial properties of FPH are substantiated. Microencapsulation using nanoliposomes effectively extends the inhibitory activity and enhances antioxidant and antibacterial capacities. Nevertheless, more research is needed to mitigate the bitter taste associated with FPH and enhance sensory attributes.

Employing fruit juices to hydrolyze edible bird's nest and enhance the antioxidant, anti-tyrosinase, and wound-healing activities of the hydrolysates

Enzymatic hydrolysis of edible bird's nest (EBN) has attracted great interest in both scientific and commercial fields due to the enhancement of solubility and nutraceutical values. The present study attempted to investigate the hydrolysis of EBN with papaya (Carica papaya L.), pineapple (Ananas comosus (L.) Merr.), and cantaloupe (Cucumis melo L.) juices as well as two commercial enzymes papain and bromelain. Our analysis revealed that EBN hydrolysis with pineapple juice and bromelain produced a degree of hydrolysis (DH) value of approximately 27 % while it was about 25 % for the hydrolysis with cantaloupe juice and 22 % for the hydrolysis with papaya juice and papain after 4 h of treatment. When EBN was digested by fruit juices and enzymes, the protein solubility and free sialic acid content were increased and the highest values were achieved for EBN hydrolysis with pineapple juice and bromelain (estimately 11 mg/mL of soluble protein and 18 g/kg of free sialic acid). The ABTS•+-scavenging, •OH-scavenging, and anti-tyrosinase capacities were higher in the EBN hydrolysates by papaya juice (IC50 of 0.034, 0.108, and 0.419 mg/mL, respectively), pineapple juice (IC50 of 0.025, 0.045, and 0.190 mg/mL, respectively), and cantaloupe juice (IC50 of 0.031 mg/mL, 0.056, and 0.339 mg/mL, respectively) than in the hydrolysates by unhydrolyzed EBN (IC50 of 0.094, 0.366, and 1.611 mg/mL, respectively). An improvement in ABTS•+-scavenging, •OH-scavenging, and anti-tyrosinase abilities was also observed for the hydrolysates by papain (IC50 of 0.041, 0.129, and 0.417 mg/mL, respectively) and bromelain (IC50 of 0.025, 0.069, and 0.336 mg/mL, respectively) but in a lesser extent as compared to the hydrolysates by respective papaya and pineapple juices. Noticeably, the EBN hydrolysates by fruit juices remarkably enhanced the wound closure in human fibroblasts by about 1.4-1.8 times after 24 h of treatment whereas this property was insignificant in the hydrolysates by enzymes. As papaya, pineapple, and cantaloupe juices are easily obtainable and have pleasant flavors, our results provide a possible method to hydrolyze EBN and apply the resultant hydrolysates in functional food products.

Aspartic protease supplementation enhancing the performance, carcass characteristics, nutrient digestibility and economic viability, without changing blood parameters and salivary cortisol of pigs

Aiming to study the performance, carcass characteristics, nutrient digestibility, blood parameters, salivary cortisol levels, and economic viability of pigs administered aspartic protease, a total of 135 pigs were housed in pens in a randomized block design, divided into five treatments with nine replications. The experimental diets were positive control (PC), basic diet with a 5.0% reduction in protein and amino acid requirements; negative control (NC) with a 7.5% reduction in protein and amino acid requirements; NC + 100 g/mT of aspartic protease (NC100); NC + 150 g/mT of aspartic protease (NC150); and NC + 200 g/mT of neutral serine protease (NC200). The inclusion of protease, independently of the source and amount, increased the average daily weight gain (P < 0.05) of animals compared with the control treatments (PC and NC), improved feed conversion (P < 0.05) in early stages, and improved diet digestibility (P < 0.05) compared with the PC. Treatment with NC150 and NC200 resulted in greater carcass weights (P < 0.05) than treatment with the PC. NC100 led to a greater carcass yield than PC (P < 0.05), and NC150 resulted in a greater loin eye area than PC (P < 0.05). No differences (P > 0.05) in the blood parameters or salivary cortisol levels were found. Regarding economic viability, proteases increased the profitability, with NC150 leading to the best results. Thus, the use of aspartic proteases is recommended to improve performance and further facilitate pork production.

Characterization of Yeast Protein Hydrolysate for Potential Application as a Feed Additive

Yeast protein can be a nutritionally suitable auxiliary protein source in livestock food. The breakdown of proteins and thereby generating high-quality peptide, typically provides nutritional benefits. Enzyme hydrolysis has been effectively uesed to generate peptides; however, studies on the potential applications of different types of enzymes to produce yeast protein hydrolysates remain limited. This study investigated the effects of endo- (alcalase and neutrase) and exotype (flavourzyme and prozyme 2000P) enzyme treatments on yeast protein. Endotype enzymes facilitate a higher hydrolysis efficiency in yeast proteins than exotype enzymes. The highest degree of hydrolysis was observed for the protein treated with neutrase, which was followed by alcalase, prozyme 2000P, and flavourzyme. Furthermore, endotype enzyme treated proteins exhibited higher solubility than their exotype counterparts. Notably, the more uniform particle size distribution was observed in endotype treated yeast protein. Moreover, compared with the original yeast protein, the enzymatic protein hydrolysates possessed a higher content of β-sheets structures, indicating their higher structural stability. Regardless of enzyme type, enzyme treated protein possessed a higher total free amino acid content including essential amino acids. Therefore, this study provides significant insights into the production of protein hydrolysates as an alternative protein material.

Molecular docking studies on α-amylase inhibitory peptides from milk of different farm animals

Milk-derived peptides have emerged as a popular mean to manage various lifestyle disorders such as diabetes. Fermentation is being explored as one of the faster and efficient way of producing peptides with antidiabetic potential. Therefore, in this study, an attempt was made to comparatively investigate the pancreatic α-amylase (PAA) inhibitory properties of peptides derived from milk of different farm animals through probiotic fermentation. Peptide's identification was carried out using liquid chromatography-quadrupole time-of-flight mass spectrometry and inhibition mechanisms were characterized by molecular docking. Results obtained showed a PAA-IC50 value (the amount of protein equivalent needed to inhibit 50% of enzymes) between 2.39 and 36.1 µg protein equivalent for different fermented samples. Overall, Pediococcus pentosaceus MF000957-derived fermented milk from all animals indicated higher PAA inhibition than other probiotic derived fermented milk (PAA-IC50 values of 6.01, 3.53, 15.6, and 10.8 µg protein equivalent for bovine, camel, goat, and sheep fermented milk). Further, molecular docking analysis indicated that camel milk-derived peptide IMEQQQTEDEQQDK and goat milk-derived peptide DQHQKAMKPWTQPK were the most potent PAA inhibitory peptides. Overall, the study concluded that fermentation derived peptides may prove useful in for managing diabetes via inhibition of carbohydrate digesting enzyme PAA.

Screening, separation and identification of metal-chelating peptides for nutritional, cosmetics and pharmaceutical applications

Metal-chelating peptides, which form metal-peptide coordination complexes with various metal ions, can be used as biofunctional ingredients notably to enhance human health and prevent diseases. This review aims to discuss recent insights into food-derived metal-chelating peptides, the strategies set up for their discovery, their study, and identification. After understanding the overall properties of metal-chelating peptides, their production from food-derived protein sources and their potential applications will be discussed, particularly in nutritional, cosmetics and pharmaceutical fields. In addition, the review provides an overview of the last decades of progress in discovering food-derived metal-chelating peptides, addressing several screening, separation and identification methodologies. Furthermore, it emphasizes the methods used to assess peptide-metal interaction, allowing for better understanding of chemical and thermodynamic parameters associated with the formation of peptide-metal coordination complexes, as well as the specific amino acid residues that play important roles in the metal ion coordination.

Enzymolytic soybean meal-impact on growth performance, nutrient digestibility, antioxidative capacity, and intestinal health of weaned piglets

Enzymolytic soybean meal (ESBM) enriches free amino acids and small peptides, while mitigating anti-nutritional factors. Substituting soybean meal with ESBM enhances animal performance, though optimal piglet dietary supplementation levels vary. The present study aimed to assess the impact of ESBM on the growth performance, nutrient digestibility, antioxidative capacity and intestinal health of weaned piglets. A total of 120 piglets (initial body weight, 7.0 ± 0.4 kg) were randomly allocated into 4 dietary groups, each comprising 5 replicates with 6 piglets per replicate. The control group received the basal diet, while the experimental groups were fed diets containing 2, 4% or 8% ESBM as a replacement for soybean meal over 28 days. Compared with the control group, piglets supplemented with 4% ESBM exhibited a significant increase (p < 0.05) in average daily gain and the apparent total tract digestibility of dry matter, ether extract and gross energy (p < 0.05), alongside a notable decrease (p < 0.05) in diarrhea incidence. Fed ESBM linearly increased (p < 0.05) the villus height in the ileum of piglets. The levels of superoxide dismutase and total antioxidant capacity in serum of piglets increased (p < 0.05) in the 2 and 4% ESBM groups, while diamine oxidase content decreased (p < 0.05) in the 4 and 8% ESBM group. ESBM inclusion also upregulated (p < 0.05) the expression of superoxide dismutase 1 (SOD-1), Catalase (CAT) and claudin-1 mRNA. In terms of cecal fermentation characteristics, ESBM supplementation resulted in a increase (p < 0.05) in valerate content and a linear rise (p < 0.05) in propionate, butyrate, and total short-chain fatty acids levels, accompanied by a decrease (p < 0.05) in the concentrations of tryptamine and NH3 in cecal digesta. ESBM had no discernible effect on cecal microbial composition. In summary, substitution of soybean meal with ESBM effectively improved the growth performance of piglets by enhancing nutrient digestibility, antioxidant capacity, intestinal barrier and cecal microbial fermentation characteristics, with the optimal replacement level identified at 4%.

Influence of a Mixture of Protein Hydrolysate from Black Soldier Fly Larvae and Schizochytrium on Palatability, Plasma Biochemistry, and Antioxidative and Anti-Inflammatory Capacity in Cat Diets

The objective of this research was to evaluate palatability, plasma biochemistry, antioxidative and anti-inflammatory capacity, and immune levels in cats by feeding supplementing inclusion of different levels of a mixture of protein hydrolysate from black soldier fly larvae and schizochytrium (BSFPs) in diets. In the feed experiment, a total of 24 adult cats (12 females and 12 males; BW: 3.02 ± 0.06 kg) were randomly divided into four groups: (1) diet with chicken and fish meal as primary protein resource (CON); (2) diet with 5% BSFPs replacing chicken meal, fish meal, chicken oil, and fish oil (5% BSFPs); (3) 10% BSFPs; and (4) 15% BSFPs. The body weight and feed intake were recorded, and a blood sample was collected for analysis. In the palatability experiment, three diets containing 5%, 10%, and 15% BSFPs were evaluated by comparing with CON. These results suggested that different levels of BSFPs could improve palatability in cat diets by enhancing the first sniff, the first bite, and feed intake (p < 0.05). However, no significant influence existed in body weight and average daily feed intake (p > 0.05). In comparison to the CON group, 5% and 15% BSFPs significantly increased the total protein content, and all treatment groups decreased the triglyceride content and enhanced the calcium concentration in plasma; in addition, the activity of aspartate aminotransferase and alanine aminotransferase and the content of creatinine and urea nitrogen were significantly reduced by the supplementation inclusion of BSFPs in the diets (p < 0.05). The enzyme activity of glutathione peroxidase was dramatically enhanced by the supplementation of 10% and 15% BSFPs in diets compared with the CON diet, and the activity of superoxide dismutase was increased and the malondialdehyde concentration was remarkably reduced in all three treatments (p < 0.05). Compared with the CON group, different levels of BSFPs in the diets significantly increased the immunoglobulin A content in plasma; similarly, the immunoglobulin G concentration was significantly enhanced by the supplementation of 10% and 15% BSFPs in the diets (p < 0.05). Furthermore, the interleukin-1β content was significantly reduced in the inclusion of 10% and 15% BSFPs in the diets, and 15% BSFPs remarkably decreased the content of interleukin-8 in plasma compared with the CON diet (p < 0.05). To sum up, the supplementation of different levels of BSFPs exhibited a positive effect on palatability and enhanced the antioxidant, anti-inflammatory, and immune capacity. Particularly, the addition levels of 10% and 15% BSFPs were more effective in antioxidation, anti-inflammation, and immunity.

Preparation of Yeast Extract from Brewer's Yeast Waste and Its Potential Application as a Medium Constituent

Yeast extract serves as a source of nutritional components essential for human dietary requirements, feed formulations, and the vital growth factors and nutrients necessary for microorganisms. However, the production cost of yeast extract using cultivated active dry yeast is relatively high. This study aims to utilize the autolysis of discarded yeast post beer brewing to produce yeast extract. The concentration, temperature, pH, and time conditions are systematically optimized. It reveals that the yield of amino nitrogen and solids in the extract was increased by 3.3% and 20.9% under the optimized conditions (1.2% wall-breaking enzyme, 1% yeast extract enzyme, and a hydrolysis time of 24 h) than that of the documented 4.03% and 69.05%. Additionally, a comparative analysis with commercially available yeast powder demonstrates that the yeast extract derived from this study adequately fulfills the nutritional requirements for microbial growth. Hence, the utilization of discarded beer yeast presents an opportunity for the valuable reclamation of waste yeast, showcasing promising potential applications.

Recent advances in the exploration and discovery of SARS-CoV-2 inhibitory peptides from edible animal proteins

The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19), is spreading worldwide. Although the COVID-19 epidemic has passed its peak of transmission, the harm it has caused deserves our attention. Scientists are striving to develop medications that can effectively treat COVID-19 symptoms without causing any adverse reactions. SARS-CoV-2 inhibitory peptides derived from animal proteins have a wide range of functional activities in addition to safety. Identifying animal protein sources is crucial to obtaining SARS-CoV-2 inhibitory peptides from animal sources. This review aims to reveal the mechanisms of action of these peptides on SARS-CoV-2 and the possibility of animal proteins as a material source of SARS-CoV-2 inhibitory peptides. Also, it introduces the utilization of computer-aided design methods, phage display, and drug delivery strategies in the research on SARS-CoV-2 inhibitor peptides from animal proteins. In order to identify new antiviral peptides and boost their efficiency, we recommend investigating the interaction between SARS-CoV-2 inhibitory peptides from animal protein sources and non-structural proteins (Nsps) using a variety of technologies, including computer-aided drug approaches, phage display techniques, and drug delivery techniques. This article provides useful information for the development of novel anti-COVID-19 drugs.

Hydrolysed poultry byproduct meal in extruded diets for cats

Hydrolysed proteins have been shown to be potential ingredients in cat diets due to their high digestibility, presence of bioactive peptides, and relatively low antigenicity. The effects of the substitution of conventional low ash poultry byproduct meal (PBM) with hydrolysed poultry byproduct meal (HPM) as a protein source were evaluated in extruded cat diets. Five diets with similar nutrient contents were formulated: a control (CO) diet based on PBM and 4 diets with different inclusions of HPM (5%, 10%, 20%, and 30%, on an as-fed basis) replacing PBM as the protein source. The total tract apparent digestibility (CTTAD) of nutrients, faecal characteristics and microbial fermentation products, urine production and pH, nitrogen balance and urea renal excretion were evaluated using 30 healthy cats (15 males and 15 females; 4.18 ± 0.86 kg; 4.17 ± 1.38 years old), with 6 cats per diet in a complete randomised block design. When significant differences were found with the F test, the effects were evaluated by polynomial contrasts according to HPM inclusion (p < 0.05). The CTTADs of DM (89 ± 0.41%), CP (90 ± 0.36%), fat (93 ± 0.41%) and gross energy (90 ± 0.33%) were similar among treatments (p > 0.05). The faecal production, score, short-chain fatty acids and ammonia concentration were similar among treatments (p > 0.05). Isobutyric, isovaleric, valeric, and total branched-chain fatty acid contents increased quadratically (p < 0.05), with the highest level in the faeces of cats fed the diet with 20% HPM. Lactate concentration in faeces increased linearly with the inclusion of HPM (p < 0.05). Urine characteristics and urea renal excretion did not differ among treatments (p > 0.05). At 10% inclusion, HPM tended to increase the nitrogen retention of cats (p = 0.083), which may reflect the higher tryptophan, methionine, lysine, and available lysine contents of HPM in comparison to PBM. The inclusion of up to 30% HPM can be considered in cat formulations without affecting nutrient digestibility or faecal and urine characteristics. HPM tended to increase nitrogen retention and increased branched-chain fatty acids in faeces, aspects which deserves further studies.

Solar reforming as an emerging technology for circular chemical industries

The adverse environmental impacts of greenhouse gas emissions and persistent waste accumulation are driving the demand for sustainable approaches to clean-energy production and waste recycling. By coupling the thermodynamically favourable oxidation of waste-derived organic carbon streams with fuel-forming reduction reactions suitable for producing clean hydrogen or converting CO2 to fuels, solar reforming simultaneously valorizes waste and generates useful chemical products. With appropriate light harvesting, catalyst design, device configurations and waste pre-treatment strategies, a range of sustainable fuels and value-added chemicals can already be selectively produced from diverse waste feedstocks, including biomass and plastics, demonstrating the potential of solar-powered upcycling plants. This Review highlights solar reforming as an emerging technology that is currently transitioning from fundamental research towards practical application. We investigate the chemistry and compatibility of waste pre-treatment, introduce process classifications, explore the mechanisms of different solar reforming technologies, and suggest appropriate concepts, metrics and pathways for various deployment scenarios in a net-zero-carbon future.

The effects of hydrolyzed protein on macronutrient digestibility, fecal metabolites and microbiota, oxidative stress and inflammatory biomarkers, and skin and coat quality in adult dogs

Research on protein hydrolysates has observed various properties and functionalities on ingredients depending on the type of hydrolysate. The objective of this study was to evaluate the effects of hydrolyzed chicken protein that was incorporated into diets on digestibility, gut health, skin and coat health, oxidative stress, and intestinal inflammation markers in healthy adult dogs. Five complete and balanced diets were manufactured: (1) CONd: 25% chicken meal diet; (2) 5% CLHd: 5% chicken liver and heart hydrolysate plus 20% chicken meal diet; (3) CLHd: 25% chicken liver and heart hydrolysate diet; (4) 5% CHd: 5% chicken hydrolysate plus 20% chicken meal diet; (5) CHd: 25% chicken hydrolysate diet. A replicated 5 × 5 Latin square design was used which included 10 neutered adult Beagles. Each of the 5 periods consisted of a 7-d washout time and a 28-d treatment period. All diets were well accepted by the dogs. Fecal butyrate concentration was higher while fecal isovalerate and total phenol/indole were lower in dogs fed CLHd than CONd (P < 0.05). Dogs fed CHd had higher fecal immunoglobulin A concentration when compared with CLHd (P < 0.05); however, both groups were comparable to the CONd. There was no difference among groups in serum cytokine concentrations, serum oxidative stress biomarkers, or skin and coat health analyses (P > 0.05). Fecal microbiota was shifted by CLHd with higher abundance in Ruminococcus gauvreauii group as well as lower Clostridium sensu stricto 1, Sutterella, Fusobacterium, and Bacteroides when compared with CONd (P < 0.05). There was also a difference in beta diversity of fecal microbiota between CLHd and CHd (P < 0.05). In conclusion, chicken protein hydrolysate could be incorporated into canine extruded diets as a comparable source of protein to traditional chicken meal. The test chicken protein hydrolysates showed the potential to support gut health by modulating immune response and microbiota; however, functional properties of protein hydrolysates are dependent on inclusion level and source.

Characteristics of Nutrition and Metabolism in Dogs and Cats

Domestic dogs and cats have evolved differentially in some aspects of nutrition, metabolism, chemical sensing, and feeding behavior. The dogs have adapted to omnivorous diets containing taurine-abundant meat and starch-rich plant ingredients. By contrast, domestic cats must consume animal-sourced foods for survival, growth, and development. Both dogs and cats synthesize vitamin C and many amino acids (AAs, such as alanine, asparagine, aspartate, glutamate, glutamine, glycine, proline, and serine), but have a limited ability to form de novo arginine and vitamin D3. Compared with dogs, cats have greater endogenous nitrogen losses and higher dietary requirements for AAs (particularly arginine, taurine, and tyrosine), B-complex vitamins (niacin, thiamin, folate, and biotin), and choline; exhibit greater rates of gluconeogenesis; are less sensitive to AA imbalances and antagonism; are more capable of concentrating urine through renal reabsorption of water; and cannot tolerate high levels of dietary starch due to limited pancreatic α-amylase activity. In addition, dogs can form sufficient taurine from cysteine (for most breeds); arachidonic acid from linoleic acid; eicosapentaenoic acid and docosahexaenoic acid from α-linolenic acid; all-trans-retinol from β-carotene; and niacin from tryptophan. These synthetic pathways, however, are either absent or limited in all cats due to (a) no or low activities of key enzymes (including pyrroline-5-carboxylate synthase, cysteine dioxygenase, ∆6-desaturase, β-carotene dioxygenase, and quinolinate phosphoribosyltransferase) and (b) diversion of intermediates to other metabolic pathways. Dogs can thrive on one large meal daily, select high-fat over low-fat diets, and consume sweet substances. By contrast, cats eat more frequently during light and dark periods, select high-protein over low-protein diets, refuse dry food, enjoy a consistent diet, and cannot taste sweetness. This knowledge guides the feeding and care of dogs and cats, as well as the manufacturing of their foods. As abundant sources of essential nutrients, animal-derived foodstuffs play important roles in optimizing the growth, development, and health of the companion animals.

Nutritional Strategies to Mitigate Post-Weaning Challenges in Pigs: A Focus on Glucans, Vitamin D, and Selenium

This review examines the challenges faced by the pig industry, with a specific focus on improving the health and growth of weaned pigs. It emphasizes the immediate necessity of investigating alternative approaches to managing pig nutrition and health due to restrictions on the use of antibiotics and the prohibition of zinc oxide in weaned pig diets. The weaning phase is identified as a critical stage in piglet development, characterized by stressors that affect their gastrointestinal health, immune responses, and overall physiology. The primary challenge during weaning arises from transitioning piglets from a digestible milk-based diet to a less digestible cereal-based feed, causing nutritional stress. This manifests as reduced feed intake, leading to gastrointestinal disturbances, intestinal inflammation, and adverse effects on intestinal structure and microbiota. To address these challenges and optimize piglet development, various nutritional strategies have been explored. Notably, glucans, particularly β-glucans from fungi, cereals, algae, and yeast, show promise in alleviating weaning-related issues. Furthermore, it is important to highlight the critical roles played by Vitamin D and selenium in piglet nutrition. These essential nutrients can be sourced naturally from enriched mushrooms that are specifically enriched with Vitamin D and selenium, providing a sustainable dietary option. In conclusion, effective nutritional strategies, including glucans, Vitamin D, selenium, and enriched mushrooms, are beneficial for addressing weaning-related challenges.

Growth performance of broiler chickens fed diets supplemented with amylase and protease enzymes individually or combined

Background

Feed additives that increase nutrient availability in feeds have gained a lot of interest.

Aim

An experiment was conducted to determine whether amylase, protease, and their combined supplementation affected broiler performance.

Methods

Two hundred eighty broiler chicks were selected and distributed randomly into 28 replicate pens with four treatment groups and seven replicates under a completely randomized design. A total of four diets were developed, having 0, 100, 100, and 100 + 100 g of control (AP0), amylase (A1), protease (P1), and amylase + protease (AP1)/ton of feed, respectively. Four replicates of each treatment were fed each diet. Each diet was randomly allotted to each group. Ad-libitum feeding was provided to the birds. The feeding program had starter and finisher diets. Upon completion of the experiment, three birds from each pen were slaughtered to analyze the carcass characteristics and organ weight.

Results

Differences were insignificant between 100 g/ton of amylase supplementation and FI, body weight gain (BWG), or feed conversion ratio (FCR) (p > 0.05). Supplementation with 10 0g/ton of protease did not significantly affect FI, BWG, and FCR (p > 0.05). Similarly, 100 + 100 g/ton of amylase + protease addition had no significant effect on FI, BWG, and FCR (p > 0.05). None of the treatments significantly affected carcass weight, abdominal fat percentage, dressing percentage, drumstick, wings, breast, and thigh weights (p > 0.05). In addition, there were no significant effects (p > 0.05) on the weight of the heart, liver, gizzard, and spleen.

Conclusion

In conclusion, amylase, protease, and their combined supplementation at a rate of 100 g/ton of feed did not influence BWG, FI, FCR, carcass characteristics, or organ weight.

Immobilized enzyme microreactors for analysis of tryptic peptides in β-casein and β-lactoglobulin

In this study, our primary objective was to develop an effective analytical method for studying trypsin-digested peptides of two proteins commonly found in cow's milk: β-casein (βCN) and β-lactoglobulin (βLG). To achieve this, we employed two distinct approaches: traditional in-gel protein digestion and protein digestion using immobilized enzyme microreactors (μ-IMER). Both methods utilized ZipTip pipette tips filled with C18 reverse phase media for sample concentration. The μ-IMER was fabricated through a multi-step process that included preconditioning the capillary, modifying its surface, synthesizing a monolithic support, and further surface modification. Its performance was evaluated under HPLC chromatography conditions using a small-molecule trypsin substrate (BAEE). Hydrolysates from both digestion methods were analyzed using MALDI-TOF MS. Our findings indicate that the μ-IMER method demonstrated superior sequence coverage for oxidized molecules in βCN (33 ± 1.5%) and βLG (65 ± 3%) compared to classical in-gel digestion (20 ± 2% for βCN; 49 ± 2% for βLG). The use of ZipTips further improved sequence coverage in both classical in-gel digestion (26 ± 1% for βCN; 60 ± 4% for βLG) and μ-IMER (41 ± 3% for βCN; 80 ± 5% for βLG). Additionally, phosphorylations were identified. For βCN, no phosphorylation was detected using classical digestion, but the use of ZipTips showed a value of 27 ± 4%. With μ-IMER and μ-IMER-ZipTip, the values increased to 30 ± 2% and 33 ± 1%, respectively. For βLG, the use of ZipTip enabled the detection of a higher percentage of modified peptides in both classical (79 ± 2%) and μ-IMER (79 ± 4%) digestions. By providing a comprehensive comparison of traditional in-gel digestion and μ-IMER methods, this study offers valuable insights into the advantages and limitations of each approach, particularly in the context of complex biological samples. The findings set a new benchmark in protein digestion and analysis, highlighting the potential of μ-IMER systems for enhanced sequence coverage and post-translational modification detection.

Sweet Taste Receptors and Associated Sweet Peptides: Insights into Structure and Function

Long-term consumption of a high-sugar diet may contribute to the pathogenesis of several chronic diseases, such as obesity and type 2 diabetes. Sweet peptides derived from a wide range of food sources can enhance sweet taste without compromising the sensory properties. Therefore, the research and application of sweet peptides are promising strategies for reducing sugar consumption. This work first outlined the necessity for global sugar reduction, followed by the introduction of sweet taste receptors and their associated transduction mechanisms. Subsequently, recent research progress in sweet peptides from different protein sources was summarized. Furthermore, the main methods for the preparation and evaluation of sweet peptides were presented. In addition, the current challenges and potential applications are also discussed. Sweet peptides can stimulate sweetness perception by binding sweet taste receptors T1R2 and T1R3 in taste buds, which is an effective strategy for reducing sugar consumption. At present, sweet peptides are mainly prepared artificially by synthesis, hydrolysis, microbial fermentation, and bioengineering strategies. Furthermore, sensory evaluation, electronic tongues, and cell models have been used to assess the sweet taste intensity. The present review can provide a theoretical reference for reducing sugar consumption with the aid of sweet peptides in the food industry.

Enzymatically Hydrolyzed Poultry By-Product Supplementation, Instead of Fishmeal, Alone Improves the Quality of Largemouth Bass (Micropterus salmoides) Back Muscle without Compromising Growth

This study was designed to investigate the effects of enzymatically hydrolyzed poultry by-products (EHPB) on the growth and muscle quality of largemouth bass. Different concentrations of EHPB (0.00, 3.10, 6.20, 9.30, and 12.40%) were added to replace fishmeal (0.00 (control), 8.89 (EHPB1), 17.78 (EHPB2), 26.67 (EHPB3), and 35.56% (EHPB4)), respectively, in dietary supplementation. The results revealed that the growth performance and muscle amino acid and fatty acid remained unaltered in EHPB1 (p > 0.05). EHPB1 showed significant reduction in muscle hardness, gumminess, chewiness, and muscle fiber count and exhibited a significant increase in muscle fiber volume. The decrease in muscle hardness, gumminess, and chewiness means that the muscle can have a more tender texture. The expression of protein metabolism-related genes reached the highest levels in EHPB1 and EHPB2 (p < 0.05). The mRNA levels of s6k and igf-1 in EHPB2 and EHPB1 were significantly lower than those in the control group. Compared to the control group, the expression of muscle production-associated genes paxbp-1 was higher in EHPB1, and myod-1, myf-5, and syndecan-4 were higher in EHPB2. The mRNA levels of muscle atrophy-related genes, in EHPB4 and EHPB2, were significantly lower than those in the control group. Therefore, the EHPB1 group plays a role in promoting the expression of genes related to muscle formation. In summary, replacing 8.89% of fishmeal with EHPB in feed has no effect on growth and may improve back muscle quality in largemouth bass.

Antimicrobial and anticarcinogenic activity of bioactive peptides derived from abalone viscera (Haliotis fulgens and Haliotis corrugata)

Bioactive peptides have been studied in several sources due to their valuable potential in the pharmaceutical and food industries. Abalone viscera, which are normally discarded as byproducts, are a rich source of protein. Thus, the aim of this study was to explore the potential bioactivity of peptides derived from abalone viscera (Haliotis fulgens and Haliotis corrugata) after hydrolysis with a commercial mixture of enzymes. The hydrolysates obtained were fractionated using gel filtration chromatography. The resulting hydrolysate fractions were investigated for their antimicrobial and cytotoxic activities, including the expression of gelatinases mmp-2 and mmp-9 in human prostate cancer cell lines (PC3). Results showed antimicrobial activity for protein fractions of H. corrugata against Proteus mirabilis and Pseudomona aeuroginosa (66.2-116.25 kDa), Bacillus subtilis (6.5-21.5 kDa), and Aspergillus niger (97.4-116.25 kDa), while H. fulgens peptide fractions (200-31 kDa) displayed activity against six bacterial strains, and fractions from 116.25 to 21.5 kDa had effects on the fungus A. niger, Alternaria alternata, and Aspergillus flavus. Additionally, protein fractions displayed cytotoxic activity, inhibiting 30.4-53.8% of PC3 cellular growth. Selected fractions decreased the PMA-induced and not-induced expressions of mmp-2 and mmp-9 in PC3 cells. Abalone viscera, as byproducts, can be used as a potential source of antimicrobial and anticancer peptides.

Effects of Diets Based on Hydrolyzed Chicken Liver and Different Protein Concentrations on the Formation and Deamination of Biogenic Amines and Total Antioxidant Capacity of Dogs

Biogenic amines are synthesized through the bacterial decarboxylation of amino acids, commonly found in high levels in animal by-product meals due to spoilage. Furthermore, biogenic amines and other metabolites can be produced by the fermentation of proteins in the hindgut according to the protein source and concentration of crude protein (CP) in the diet. Thus, this study aimed to evaluate two protein sources (poultry by-product meal (PBPM) and hydrolyzed chicken liver powder (HCLP)) and three CP concentrations (24, 32, and 40%) and their effects on the consumption and fecal excretion of biogenic amines, plasma monoamine oxidase (MAO) and diamine oxidase (DAO) activities, and total antioxidant capacity (TAC) of healthy adult dogs after 30 days of feeding the experimental diets. Twelve dogs were randomly distributed into six treatments (n = 6/treatment): PBPM24 (PBPM with 24% CP); PBPM32 (PBPM with 32% CP); PBPM40 (PBPM with 40% CP); HCLP24 (HCLP with 24% CP); HCLP32 (HCLP with 32% CP); HCLP40 (HCLP with 40% CP). The PBPM and PBPM-based diets had higher concentrations of putrescine, cadaverine, tyramine, histamine, agmatine, and total biogenic amines. In contrast, HCLP and HCLP-based diets contained higher concentrations of spermidine, phenylethylamine, and spermine. The PBPM and PBPM-diets had higher biogenic amine index (BAI) indicating lower quality due to the high content of putrescine, cadaverine and tyramine. Dogs fed diets with PBPM and higher protein concentrations consumed more putrescine, cadaverine, tyramine, agmatine, and total amines (p < 0.0001), while dogs fed with HCLP consumed more spermidine, phenylethylamine, and spermine (p < 0.0001). Fecal excretion of phenylethylamine was greater in dogs fed HCLP32 and HCLP40 diets (p = 0.045). Dogs fed with HCLP tended to excrete more spermidine and tryptamine via feces, while higher protein concentrations tended to increase fecal excretion of cadaverine (p < 0.10). Plasma MAO activity was higher in dogs fed HCLP24 and PBPM32 diets (p = 0.024). The plasma activities of DAO and TAC were not different between diets (p > 0.05). Although we did not evaluate the intestinal activities of MAO and DAO, our results suggest that healthy adult dogs have an efficient deamination process on the gut epithelium.

Effects of a new generation of fish protein hydrolysate on performance, intestinal microbiology, and immunity of broiler chickens

This study was conducted to evaluate the effects of co-dried fish protein hydrolysate (CFPH) on broilers performance, intestinal microbiology, and cellular immune responses. Five hundred one-day-old (Ross 308) male broilers were allocated to four treatments with five replicates of 25 birds in a completely randomized design. The experimental treatments included four levels of CFPH (0% as the control, 2.5%, 5%, and 7.5%) in the isonitrogenous and isocaloric diets. During the experiment, body weight (BW) and feed intake (FI) were periodically recorded in addition to calculating average daily gain (ADG), feed conversion ratio (FCR), liveability index, and European broiler index (EBI). In addition, cellular immune responses were evaluated at 30 days of age. On day 42, ileal contents were obtained to examine the microbial population. Based on the findings, Dietary supplementation of 5 and 7.5% CFPH increased the percentage of the thigh while decreasing the relative weight of the gizzard compared to the control group. The highest relative length of jejunum was observed in birds receiving 2.5 and 5% CFPH, and its highest relative weight belonged to birds fed with 5% CFPH. The number of coliforms, enterobacters, and total gram-negative bacteria in the intestines of birds receiving CFPH was less than that of the control group. In general, the application of CFPH in broiler nutrition can decrease the level of soybean meal in diet and it can be considered as a new protein supplement in poultry production. It is suggested to study the incorporation of this new supplement in other livestock's diets.

Toward the high-efficient utilization of poultry blood: Insights into functionality, bioactivity and functional components

A large amount of poultry blood is annually generated, and currently underutilized or largely disposed of as waste, resulting in environmental pollution and waste of protein resources. As one of the main by-products during the poultry slaughter process, the produced poultry blood can serve as a promising food ingredient due to its excellent functional properties and abundant source of essential amino acids, bioactive peptides and functional components. This work provides a comprehensive summary of recent research progress in the composition, functional and bioactive properties, as well as the functional components of poultry blood. Furthermore, the main preparation methods of poultry blood-derived peptides and their bioactivities were reviewed. In addition, their potential applications in the food industry were discussed. Overall, poultry blood is characterized by excellent functionalities, including solubility, gelation, foaming, and emulsifying properties. The major preparation methods for poultry blood-derived peptides include enzymatic hydrolysis, ultrasound-assisted enzymatic methods, macroporous adsorbent resins, and subcritical water hydrolysis. Poultry blood-derived peptides exhibit diverse bioactivities. Their metallic off-flavors and bitterness can be improved by exopeptidase treatment, Maillard reaction, and plastein reaction. In addition, poultry blood is also abundant in functional components such as hemoglobin, superoxide dismutase, immunoglobulin, and thrombin.

Prospects on emerging eco-friendly and innovative technologies to add value to dry bean proteins

The world's growing population and evolving food habits have created a need for alternative plant protein sources, with pulses playing a crucial role as healthy staple foods. Dry beans are high-protein pulses rich in essential amino acids like lysine and bioactive peptides. They have gathered attention for their nutritional quality and potential health benefits concerning metabolic syndrome. This review highlights dry bean proteins' nutritional quality, health benefits, and limitations, focusing on recent eco-friendly emerging technologies for their obtaining and functionalization. Antinutritional factors (ANFs) in bean proteins can affect their in vitro protein digestibility (IVPD), and lectins have been identified as potential allergens. Recently, eco-friendly emerging technologies such as ultrasound, microwaves, subcritical fluids, high-hydrostatic pressure, enzyme technology, and dry fractionation methods have been explored for extracting and functionalizing dry bean proteins. These technologies have shown promise in reducing ANFs, improving IVPD, and modifying allergen epitopes. Additionally, they enhance the techno-functional properties of bean proteins, making them more soluble, emulsifying, foaming, and gel-forming, with enhanced water and oil-holding capacities. By utilizing emerging innovative technologies, protein recovery from dry beans and the development of protein isolates can meet the demand for alternative protein sources while being eco-friendly, safe, and efficient.

Use of Esienia fetida Worms to Produce Peptone for Clostridium perfringens Vaccine Production

Concurrent with an increase in the human population on the earth, more than ever, the creation of energy and maintenance of health is necessary, and nowadays, various sources of energy supply are being developed. The general global view in this regard is to provide protein and energy from available and cheap sources. Iran is no exception to this general rule, only in the field of ensuring the health of livestock resources every year, about 10 tons of peptone is needed for producing clostridial vaccines. Vermicomposting worms (Esienia fetida) with high protein percentages and rapid reproductions are a suitable source for peptone production. Based on this, the vaccine strain of Clostridium perfringens type D cultivated in two different media contain peptone produced from worms and meat peptone. The growth rate, epsilon toxin (ETX), and alpha toxin (CPA) of Cl. perfringens have been compared in two media. The results showed that the growth rate of bacteria in the worm peptone medium in 48 h was 22% higher than that of the meat peptone. Additionally, the activity of alpha toxin (phospholipase C) was in worm peptone 15% higher than meat peptone during 80 min of measurement. Regarding epsilon toxin lethality, all three mice of the N-worm peptone group died, while all three mice of the meat peptone group survived even 72 h after injection. The average survival time of mice in the N-worm peptone group was 1700 min. Therefore, we suggest the worms' protein is more suitable than industrial meat in peptone production for vicinal propose. To eliminate the need for hydrolyzed protein in the production of vaccines in the future, we suggest an increase in the fields of employment and the development of fertilizer and worm farms in Iran.

Peculiarities in the Amino Acid Composition of Sow Colostrum and Milk, and Their Potential Relevance to Piglet Development

The composition of mother's milk is considered the ideal diet for neonates. This study investigated how conserved or variable the amino acid profile of sow colostrum and milk is throughout lactation, compared with other studies in sows and other species. Twenty-five sows (parity one to seven) from one farm with gestation lengths of 114 to 116 d were sampled on d 0, 3, and 10 after parturition. The total amino acid profile of the samples was analyzed through ion-exchange chromatography, and the results were displayed as the percentage of total amino acid and compared with literature data. Most of the amino acid concentrations in sow milk decreased significantly (p < 0.05) throughout the lactation period, while the amino acid profile generally showed a conserved pattern, especially from d 3 to d 10, and was rather similar across different studies. Glutamine + glutamate was the most abundant amino acid in milk at all sampling moments, accounting for 14-17% of total amino acids. The proportions of proline, valine, and glycine in sow milk nearly accounted for 11%, 7%, and 6% respectively, and were higher compared to human, cow, and goat milk, while the methionine proportion was less than the other three. Compared to the large variations often reported in macronutrient concentrations, the amino acid profile of sow milk in the present study, as well as in others, seems well conserved across the lactation period. Similarities with characteristic differences were also observed between sow milk and piglet body composition, which might reflect the nutrition requirements of preweaning piglets. This study warrants further research exploring the link between the whole amino acid profile and the particular amino acids for suckling piglets and could facilitate insight for optimizing creep feed.

Bioactive Antimicrobial Peptides from Food Proteins: Perspectives and Challenges for Controlling Foodborne Pathogens

Bioactive peptides (BAPs) derived from food proteins have been extensively studied for their health benefits, majorly exploring their potential use as nutraceuticals and functional food components. These peptides possess a range of beneficial properties, including antihypertensive, antioxidant, immunomodulatory, and antibacterial activities, and are naturally present within dietary protein sequences. To release food-grade antimicrobial peptides (AMPs), enzymatic protein hydrolysis or microbial fermentation, such as with lactic acid bacteria (LAB), can be employed. The activity of AMPs is influenced by various structural characteristics, including the amino acid composition, three-dimensional conformation, liquid charge, putative domains, and resulting hydrophobicity. This review discusses the synthesis of BAPs and AMPs, their potential for controlling foodborne pathogens, their mechanisms of action, and the challenges and prospects faced by the food industry. BAPs can regulate gut microbiota by promoting the growth of beneficial bacteria or by directly inhibiting pathogenic microorganisms. LAB-promoted hydrolysis of dietary proteins occurs naturally in both the matrix and the gastrointestinal tract. However, several obstacles must be overcome before BAPs can replace antimicrobials in food production. These include the high manufacturing costs of current technologies, limited in vivo and matrix data, and the difficulties associated with standardization and commercial-scale production.

A review on the processing of functional proteins or peptides derived from fish by-products and their industrial applications

To understand the production and characteristics of protein hydrolysates pertaining to individual fish species, we selected and analyzed the most important commercial fish species according to the market value based on the Statistics on International Exports of Fishery Commodities by Food and Agriculture Organization. Accordingly, salmon, shrimp, cod, tuna, squid, and herring are marine species with high global value. Peptides obtained from their by-products were predominant in hydrophobic amino acids such as alanine, phenylalanine, methionine, proline, valine, tyrosine, tryptophan, leucine, and isoleucine. Bioactive peptides are short with a length of 2-20 amino acids. They remain inactive when they are within their parent proteins. Low molecular weight (0.3-8 kDa) peptides from hydrolyzed protein are easily digestible, readily absorbed by the body and are water-soluble. The hydrophobic nature contributes to their bioactivity, which facilitates their interactions with the membrane lipid bilayers. Incomplete hydrolysis results in low yields of hydrophobic amino acids. The glycosylation type of the resulting peptide fragment determines the different applications of the hydrolysate. The degree of conservation of the glycosidic residues and the size of the peptides are influenced by the method used to generate these hydrolysates. Therefore, it is crucial to explore inexpensive novel methodologies to generate bioactive peptides. According to the current studies, a unified approach (in silico estimation coupled with peptidomics) can be used for the identification of novel peptides with diverse physiological and technological functions. From an industrial perspective, the reusability of immobilized enzymes and membrane separation techniques (e.g., ultrafiltration) on marine by-products can offer low operating costs and higher yield for large-scale production of bioactive peptides. This review summarizes the production processes and essential characteristics of protein hydrolysates from fish by-products and presents the advances in their application.

The use of animal by-products in a circular bioeconomy: Time for a TSE road map 3?

In 2005 and 2010, the European Commission (EC) published two subsequent 'Road Maps' to provide options for relaxation of the bans on the application of animal proteins in feed. Since then, the food production system has changed considerably and demands for more sustainability and circularity are growing louder. Many relaxations envisioned in the second Road Map have by now been implemented, such as the use of processed animal proteins (PAPs) from poultry in pig feed and vice versa. However, some legislative changes, in particular concerning insects, had not been foreseen. In this article, we present a new vision on legislation for increased and improved use of animal by-products. Six current legislative principles are discussed for the bans on animal by-products as feed ingredients: feed bans; categorization of farmed animals; prohibition unless explicitly approved; approved processing techniques, the categorization of animal by-products, and monitoring methods. We provide a proposal for new guiding principles and future directions, and several concrete options for further relaxations. We argue that biological nature of farmed animals in terms of dietary preferences should be better recognised, that legal zero-tolerance limits should be expanded if safe, and that legislation should be revised and simplified.

Preparation and quality evaluation of sardines sauce rich in omega-3 using the combination of pineapple fruit extracts and fermentation times

A present study aimed at evaluating sardine sauce quality used a treatment combination of pineapple fruit extract, and fermentation times. It used a completely randomized design with a factorial pattern. The results showed a pineapple fruit extracts and fermentation times affected significantly on sardine sauce quality (P < 0.05). There was an interaction between pineapple fruit extract and fermentation times on sardine sauce quality. A pineapple fruit extract of 10% and fermentation times of 13 days produced sardine sauce best quality, with a protein content (17.38%), moisture (74.45%), omega-3 (19.68%), pH (5.23), taste value of 3.68, color of 4.52, and aroma of 2.99, respectively, but, consumers did not like it so much. It has passed a National Standard of Indonesia, which sets the minimum level of protein of 5%, and pH ranges from 5.0 to 6.0.

Amino acid nutrition and metabolism in domestic cats and dogs

Domestic cats and dogs are carnivores that have evolved differentially in the nutrition and metabolism of amino acids. This article highlights both proteinogenic and nonproteinogenic amino acids. Dogs inadequately synthesize citrulline (the precursor of arginine) from glutamine, glutamate, and proline in the small intestine. Although most breeds of dogs have potential for adequately converting cysteine into taurine in the liver, a small proportion (1.3%-2.5%) of the Newfoundland dogs fed commercially available balanced diets exhibit a deficiency of taurine possibly due to gene mutations. Certain breeds of dogs (e.g., golden retrievers) are more prone to taurine deficiency possibly due to lower hepatic activities of cysteine dioxygenase and cysteine sulfinate decarboxylase. De novo synthesis of arginine and taurine is very limited in cats. Thus, concentrations of both taurine and arginine in feline milk are the greatest among domestic mammals. Compared with dogs, cats have greater endogenous nitrogen losses and higher dietary requirements for many amino acids (e.g., arginine, taurine, cysteine, and tyrosine), and are less sensitive to amino acid imbalances and antagonisms. Throughout adulthood, cats and dogs may lose 34% and 21% of their lean body mass, respectively. Adequate intakes of high-quality protein (i.e., 32% and 40% animal protein in diets of aging dogs and cats, respectively; dry matter basis) are recommended to alleviate aging-associated reductions in the mass and function of skeletal muscles and bones. Pet-food grade animal-sourced foodstuffs are excellent sources of both proteinogenic amino acids and taurine for cats and dogs, and can help to optimize their growth, development, and health.

Utilization of lactobacillus fermented proteins from meat processing wastewaters as a dietary protein source in poultry feed

The present study aimed to evaluate the impact of fermented meat processing wastewater protein hydrolysate (FWMPH) prepared by Pediococcus lolii fermentation as an alternative protein source on growth performance, serum biochemistry, and hematological parameters of broiler chicks. FWMPH exhibited antioxidant, anti-angiotensin converting enzyme (ACE), and antimicrobial properties. A total of 60 one-day-old Vencobb broiler chicks were divided into five dietary groups on day 8 and a feeding trial was performed for 48 days. Diets were prepared by replacing soya protein concentrate (SPC) at different levels of FWMPH as the protein source. These diets were denoted as SPSD (100% SPC), FMP-25 (25% FWMPH + 75% SPC), FMP-50 (50% FWMPH + 50% SPC), FMP-75 (75% FWMPH + 25% SPC), and FMP-100 (100% FWMPH). FMP-25 and FMP-100 diet group broiler chicks showed the highest and lowest feed consumption (P < 0.05), respectively. However, the highest body weight gain (1506.08 ± 52.52 g) was observed in FMP-75 diet-fed chicks (P < 0.05). Furthermore, FMP-75 chicks displayed better feed conversion ratio (1.96), feed efficiency ratio (0.51), and protein efficiency ratio (2.32) values than other diet group chicks (P < 0.05), implying that the FMP-75 diet had better effect on the broiler growth. Also, the FMP-75 diet chicks showed better hematological values, serum biochemical parameters revealed no negative effect upon FWMPH consumption, and no pathological signs were observed in the histopathological examination as compared to the SPSD diet group (P < 0.05). Hence, the results could be helpful in the application of FWMPH at 75% level in the poultry feed as a potential protein ingredient in the countries looking for local feed protein products as soya bean meal replacement.

Yeast derivatives as a source of bioactive components in animal nutrition: A brief review

With a long history of inclusion within livestock feeding programs, yeast and their respective derivatives are well-understood from a nutritional perspective. Originally used as sources of highly digestible protein in young animal rations in order to offset the use of conventional protein sources such as soybean and fish meal, application strategies have expanded in recent years into non-nutritional uses for all animal categories. For the case of yeast derivatives, product streams coming from the downstream processing of nutritional yeast, the expansion in use cases across species groups has been driven by a greater understanding of the composition of each derivative along with deeper knowledge of mechanistic action of key functional components. From improving feed efficiency, to serving as alternatives to antibiotic growth promoters and supporting intestinal health and immunity while mitigating pathogen shedding, new use cases are driven by a recognition that yeast derivatives contain specific bioactive compounds that possess functional properties. This review will attempt to highlight key bioactive categories within industrially applicable yeast derivatives and provide context regarding identification and characterization and mechanisms of action related to efficacy within a range of experimental models.

Apparent jejunal amino acid digestibility, gut morphology, and the expression of intestinal amino acid transporters in pigs fed protein or free amino acids

Dietary amino acids (AA) supplied as protein or in free form are not only digested and absorbed at different rates but can also induce differences in the intestinal physiology of pigs. We compared the apparent jejunal AA digestibility, intestinal morphology, and gene expression of AA transporters of pigs fed diets providing different forms of AA. Thirty growing pigs (33.7 ± 4.1 kg) were fed one of three experimental diets that provided AA either as protein from feather meal (INT), as free AA and small peptides obtained by extensive acid hydrolysis of feathers (HYD), or as a mix of individual purified AA with the same AA profile as HYD (FAA). Pigs were fed the same quantity of feed, energy, and AA. After 14 d, pigs were slaughtered 3 h after feeding a meal with indigestible markers. Digesta and tissue were collected from different sections of the small intestine. Jejunal digesta was used to measure apparent jejunal digestibility of AA. Samples of the duodenum, jejunum, and ileum were used to measure intestinal morphology and the gene expression of intestinal AA transporters. The measured apparent jejunal digestibility of AA of INT was lower compared to HYD and FAA (P < 0.05). The apparent jejunal digestibility of Cys, Gly, His, Met, and Pro was lower for FAA compared to HYD (P < 0.05). This may be due to the small peptides in HYD, which are absorbed faster than individual AA. The villi area in the ileum of HYD fed pigs was the highest (P < 0.05) among the treatments, which may be associated with the reabsorption of endogenous proteins, which occurs mostly in the ileum. In the duodenum, HYD and FAA had lower expression of PepT1 (P < 0.01) probably due to the rapid transit time of digesta compared to INT fed pigs. Pigs fed HYD expressed more ASCT2 (P = 0.02) and CAT-1 (P = 0.04) in the jejunum compared to the pigs fed the other diets. The expression of these transporters along the intestine depended on the relative abundance of readily absorbable dietary AA. Results showed that dietary AA form can have an influence on the morphology and on the expression of different AA transporters along the different sections of the small intestine.

Standardized amino acid digestibility and protein quality in extruded canine diets containing hydrolyzed protein using a precision-fed rooster assay

Protein hydrolysate has become a choice of alternative protein source in canine diets as it showed greater digestibility, lower allergenic responses, and various functional properties when compared with intact proteins. The objective of the study was to determine the effect of hydrolyzed protein inclusion on amino acid digestibility and protein quality in extruded canine diets when compared with a traditional protein source for adult dogs. Five treatment diets were formulated to have similar compositions except for the main protein source. The control diet was formulated with chicken meal (CM) as the primary protein source. Test hydrolyzed proteins, chicken liver and heart hydrolysate (CLH) and chicken hydrolysate (CH) were used to partially or completely substitute CM. The diets were: CONd: CM (30%) diet; 5%CLHd: 5% CLH with 25% CM diet; CLHd: CLH (30%) diet; 5%CHd: 5% CH with 25% CM diet; CHd: CH (30%) diet. A precision-fed rooster assay was used to determine standardized amino acid digestibility for the ingredients and diets. In addition, Digestible Indispensable Amino Acid Score (DIAAS)-like values were calculated for the protein ingredients. All protein ingredients had higher than 80% of digestibility for all indispensable amino acids with no difference among sources (P > 0.05). From the DIAAS-like values referencing AAFCO nutrient profile for adult dogs, CLH and CH did not have any limiting amino acid; on the other hand, CM has a lower DIAAS-like value (93.3%) than CLH and CH (P < 0.05) with tryptophan being the first-limiting amino acid. The DIAAS-like values were often lower when the amino acid combinations methionine + cysteine and phenylalanine + tyrosine were included in the calculation. When referencing NRC recommended allowances and minimal requirements, methionine was the first-limiting amino acid for all protein sources. Amino acid digestibility was mostly above 80% and comparable among the treatment diets. Regarding the digestible indispensable amino acid concentrations in the diets, all of them met the AAFCO nutrient profile for adult dogs at maintenance. In conclusion, both protein hydrolysates were highly digestible, high-quality protein sources, and a full substitution from CM to protein hydrolysate could result in greater protein quality, according to the DIAAS-like values of the ingredients, when compared with CM in extruded canine diets.

Effects of hydrolyzed chicken liver on digestibility, fecal and urinary characteristics, and fecal metabolites of adult dogs

High-protein low-carbohydrate diets have been widely used for adult maintenance dogs, as well as in specific weight loss diets and maintenance programs. However, increasing dietary protein may increase undigested protein in the hindgut, modifying intestinal fermentation and fecal metabolite concentrations. The aim of this study was to evaluate the effects of protein source and concentration on apparent total tract digestibility (ATTD) of nutrients, metabolizable energy (ME), fecal and urinary characteristics, and fecal metabolites of dogs. Twelve healthy adult dogs were distributed into six treatments (n = 6 per diet) in a balanced incomplete Latin square design consisting of three periods of 30 days each. Six diets, varying in protein source [poultry byproduct meal (PBPM) and hydrolyzed chicken liver powder (HCLP)] and concentration [24, 32, and 40% crude protein (CP) on dry matter (DM) basis] were tested: PBPM24 (PBPM based diet with 24% CP); PBPM32 (PBPM with 32% CP); PBPM40 (PBPM with 40% CP); HCLP24 (HCLP based diet with 24% CP); HCLP32 (HCLP with 32% CP); HCLP40 (HCLP with 40% CP). The ATTD of CP was greater in dogs-fed HCLP and higher protein concentrations diets (P < 0.05). However, dogs-fed HCLP diets had lower ATTD of fat and carbohydrates, and ME (P < 0.05). Similarly, high-protein diets reduced the ATTD of DM, OM, fat, carbohydrates, and energy (P < 0.05). High-protein diets increased the daily fecal output and moisture (P = 0.004 and P < 0.05, respectively), as well as the fecal score (P < 0.0001), verified as soft, moist stools, but still within the ideal range. Fecal valerate concentration was greater in dogs-fed PBPM at 32% CP (P = 0.007). Fecal isobutyrate tended to increase in dogs-fed PBPM and high-protein diets (P < 0.10). Also, dogs-fed PBPM and high-protein diets had greater fecal concentrations of isovalerate, branched-chain fatty acids (BCFA), and ammonia (P < 0.05). Finally, the fecal lactate concentration increased in dogs-fed HCLP and high-protein diets (P < 0.05). The HCLP increased the ATTD of CP, being a highly digestible protein. Although the inclusion of HCLP slightly increased fecal score and moisture, it decreased the amount of fecal metabolites of protein fermentation ammonia and BCFA, both of which are associated with proteolytic fermentation in the colon.

Effect of antibiotics and low-crude protein diets on growth performance, health, immune response, and fecal microbiota of growing pigs

This study aimed to investigate the effects of diets with and without antibiotics supplementation and diets with 18.5% and 13.0% crude protein (CP) on growth performance, carcass characteristics, disease incidence, fecal microbiota, immune response, and antioxidant capacity of growing pigs. One hundred and eighty pigs (59-day-old; 18.5 ± 2.5 kg) were distributed in a randomized complete block design in a 2 × 2 factorial arrangement, nine replicates, and five pigs per pen. The factors were CP (18.5% or 13.0%) and antibiotics (none or 100 mg/kg tiamulin + 506 mg/kg oxytetracycline). Medicated diets were fed from days 59 to 73. After that, all pigs were fed their respective CP diets from 73 to 87 days. Data were analyzed using the Mixed procedure in SAS version 9.4. From days 59 to 73, pigs fed antibiotics diets had higher (P < 0.05) average daily feed intake (ADFI), average daily weight gain (ADG), gain to feed ratio (G:F), compared to the diets without antibiotics. From days 73 to 87 (postmedicated period), any previous supplementation of antibiotics did not affect pig growth performance. Overall (days 59 to 87), pigs-fed antibiotics diets had higher (P < 0.05) G:F compared to pigs-fed diets without antibiotics. In all periods evaluated, pigs fed 18.5% CP diets had higher (P < 0.05) ADG and G:F compared to pigs fed 13.0% CP. Pigs fed the 13.0% CP diets had lower (P < 0.05) fecal score and diarrhea incidence than those fed 18.5% CP. Pigs fed 18.5% CP diets had improved (P < 0.05) loin area compared to pigs-fed diets with 13.0% CP. At 66 days of age, pigs-fed antibiotics diets had lower (P < 0.05) alpha diversity estimated with Shannon and Simpson compared to the pig-fed diets without antibiotics. At family level, pigs fed 18.5% CP diets had higher (P < 0.05) relative abundance of Streptococcaceae, and lower (P < 0.05) relative abundance of Clostridiaceae at days 66 and 87 compared with pigs fed 13.0% CP. Pigs-fed antibiotics diets had lower (P < 0.05) immunoglobulin G and protein carbonyl concentrations at day 66 compared to the pigs-fed diets without antibiotics. The reduction of dietary CP from 18.5% to 13.0% reduced the growth performance and loin muscle area of growing pigs, although it was effective to reduce diarrhea incidence. Antibiotics improved growth performance, lowered diarrhea incidence, improved components of the humoral immune response, and reduced microbiota diversity. However, in the postmedicated period, we found no residual effect on the general health of the animals, and considering the overall period, only G:F was improved by the use of antibiotics.

Comparative analysis of the degree of hydrolysis and antioxidant activity of milk and whey hydrolysates

The degree of hydrolysis and antioxidant activity of protein hydrolysates from fresh cow’s milk and whey obtained by the action of the proteolytic enzymes papain, bromelain and chymosin were compared. The lowest degree of hydrolysis in fresh milk hydrolysates was reported for sample MP1 (10 min reaction time, treatment with 0.1 mg/ml papain), and the highest percentage was obtained at hydrolysate MB12 (at 60 min reaction time, treatment with 1.0 mg/ml bromelain). For the whey samples in sample WC1 (10 min reaction time, treatment with 1.0 μl/ml chymosin), the percentage of hydrolysis was the lowest. The highest percentage was achieved at WP12 hydrolysate using papain at a concentration of 1 mg/ml and a 60-min reaction time. The obtained values for the antioxidant capacity of the hydrolysed products show a higher activity compared to the starting substrates. The highest activity in the milk hydrolysates of 11.32 mg TE/100 ml was found in variant MB3, and in the whey hydrolysates of 7.83 mg TE/100 ml - in variant WP7. Hydrolysates treated with chymosin had lower TE values compared to the hydrolysate’s variants, treated with papain and bromelain.

Use of industry 4.0 technologies to reduce and valorize seafood waste and by-products: A narrative review on current knowledge

Fish and other seafood products represent a valuable source of many nutrients and micronutrients for the human diet and contribute significantly to global food security. However, considerable amounts of seafood waste and by-products are generated along the seafood value and supply chain, from the sea to the consumer table, causing severe environmental damage and significant economic loss. Therefore, innovative solutions and alternative approaches are urgently needed to ensure a better management of seafood discards and mitigate their economic and environmental burdens. The use of emerging technologies, including the fourth industrial revolution (Industry 4.0) innovations (such as Artificial Intelligence, Big Data, smart sensors, and the Internet of Things, and other advanced technologies) to reduce and valorize seafood waste and by-products could be a promising strategy to enhance blue economy and food sustainability around the globe. This narrative review focuses on the issues and risks associated with the underutilization of waste and by-products resulting from fisheries and other seafood industries. Particularly, recent technological advances and digital tools being harnessed for the prevention and valorization of these natural invaluable resources are highlighted.

Advances, Implications, and Limitations of Low-Crude-Protein Diets in Pig Production

Currently, five crystalline essential amino acids (Lys, Met, Thr, Trp, and Val) are generally used, allowing formulation of low-crude-protein (CP) diets. Moreover, Ile may also be used depending on its economic value and the specific feeding program. Experimentally, it has been shown that further reduced CP levels can be achieved by supplemental His, Leu, and Phe to the diets. However, decreasing the dietary CP level while maintaining optimal ratios of amino acids has shown contradictory effects on pigs' growth performance. Due to the divergence in the literature and the importance for practical formulation strategies in the swine industry, a literature review and a meta-analysis were performed to estimate the minimum CP level that would not compromise pig performance. Based on the present review, there is a minimum CP level after which the growth performance of pigs can be compromised, even though diets are balanced for essential amino acids. Considering average daily gain and gain to feed, respectively, these levels were estimated to be 18.4% CP (95% confidence interval [CI]: 16.3 to 18.4) and 18.3% CP (95% CI: 17.4 to 19.2) for nursery, 16.1% CP (95% CI: 16.0 to 16.2) and 16.3% CP (95% CI: 14.5 to 18.0) for growing, and 11.6% CP (95% CI: 10.8 to 12.3) and 11.4% CP (95% CI: 10.3 to 12.5) for finishing pigs.

Benefits of Circulating Human Metabolites from Fish Cartilage Hydrolysate on Primary Human Dermal Fibroblasts, an Ex Vivo Clinical Investigation for Skin Health Applications

Due to its significant exposure to stressful environmental factors, the skin undergoes a high remodeling rate over time, which alters not only its appearance but also its functionality. This alteration of the skin, namely photoaging, is characterized by dryness and a loss of elasticity that mainly originates from the dysregulation of dermal fibroblast activities. In order to overcome such tissue outcome, cosmetic products have evolved toward nutricosmetics, thus promoting beauty from within. Among bio-actives of interest, bio-peptides deriving from plant or animal sources may exert various biological activities beyond their nutritional value. However, studies remain mostly descriptive and the mode of action at the cellular level in clinic remains a concern. In a recent clinical trial, it was showed that supplementation with a fish cartilage hydrolysate (FCH) improved signs of chronological and photoaging-induced skin changes in healthy women. Here, using an original ex vivo clinical approach adapted to nutricosmetic purpose, we further demonstrated that this fish cartilage hydrolysate was absorbed and that the circulating metabolites produced in humans following FCH intake stimulate human dermal fibroblast growth, promote specific hyaluronan production, up-regulate elastin synthesis and inhibit MMP-1 and 3 expression along with the enhancement of TGF-β release. Altogether, these data provide clues on the mechanisms likely contributing to the beneficial impact of FCH on human skin functionality by supporting hydration, elasticity and limiting the expression of catabolic factors involved in photoaging onset.

Evaluating the Potential of Marine Invertebrate and Insect Protein Hydrolysates to Reduce Fetal Bovine Serum in Cell Culture Media for Cultivated Fish Production

The use of fetal bovine serum (FBS) and the price of cell culture media are the key constraints for developing serum-free cost-effective media. This study aims to replace or reduce the typical 10% serum application in fish cell culture media by applying protein hydrolysates from insects and marine invertebrate species for the growth of Zebrafish embryonic stem cells (ESC) as the model organism. Protein hydrolysates were produced from black soldier flies (BSF), crickets, oysters, mussels, and lugworms with a high protein content, suitable functional properties, and adequate amino-acid composition, with the degree of hydrolysis from 18.24 to 33.52%. Protein hydrolysates at low concentrations from 0.001 to 0.1 mg/mL in combination with 1 and 2.5% serums significantly increased cell growth compared to the control groups (5 and 10% serums) (p < 0.05). All protein hydrolysates with concentrations of 1 and 10 mg/mL were found to be toxic to cells and significantly reduced cell growth and performance (p < 0.05). However, except for crickets, all the hydrolysates were able to restore or significantly increase cell growth and viability with 50% less serum at concentrations of 0.001, 0.01, and 0.1 mg/mL. Although cell growth was enhanced at lower concentrations of protein hydrolysates, the cell morphology was altered due to the lack of serum. The lactate dehydrogenase (LDH) activity results indicated that BSF and lugworm hydrolysates did not alter the cell membrane. In addition, light and fluorescence imaging revealed that the cell morphological features were comparable to those of the 10% serum control group. Overall, lugworm and BSF hydrolysates reduced the serum by up to 90% while preserving excellent cell health.

Zambrano-Rodríguez P. The Use of Peptides in Veterinary Serodiagnosis of Infectious Diseases: A Review

Peptides constitute an alternative and interesting option to develop treatments, vaccines, and diagnostic tools as they demonstrate their scope in several health aspects; as proof of this, commercial peptides for humans and animals are available on the market and used daily. This review aimed to know the role of peptides in the field of veterinary diagnosis, and include peptide-based enzyme-linked immunosorbent assay (pELISA), lateral flow devices, and peptide latex agglutination tests that have been developed to detect several pathogens including viruses and bacteria of health and production relevance in domestic animals. Studies in cattle, small ruminants, dogs, cats, poultry, horses, and even aquatic organisms were reviewed. Different studies showed good levels of sensitivity and specificity against their target, moreover, comparisons with commercial kits and official tests were performed which allowed appraising their performance. Chemical synthesis, recombinant DNA technology, and enzymatic synthesis were reviewed as well as their advantages and drawbacks. In addition, we discussed the intrinsic limitations such as the small size or affinity to polystyrene membrane and mention several strategies to overcome these problems. The use of peptides will increase in the coming years and their utility for diagnostic purposes in animals must be evaluated.