Slaughterhouse Blood Research Articles

The Growth Performance and Nutrient Composition of Black Soldier Fly (Hermetia illucens) Larvae Fed Slaughtered Bovine Blood.

The disposal of slaughterhouse blood poses significant environmental challenges due to its biological instability and high nutrient content. We used a gradient of 10% blood increments (0-100%) to feed BSFL, and the correlation between the proportion of bovine blood and the BSFL weight gain, mortality rate, fatty acid content, and amino acid content was researched. Results indicate a positive correlation between the bovine blood content and BSFL mortality, with survival rates above 95% for blood proportions below 60%. Larval weight exhibited a negative correlation as the bovine blood content increased. Nutritional analysis revealed that the crude protein content in BSFL increased proportionally with bovine blood (14.75-25.45 g/100 g), while the crude fat content decreased correspondingly (10.70-4.66 g/100 g). The sugar content remained relatively constant across groups. Fatty acid analysis showed increased levels of C16:0, C14:0, and C16:1 and decreased levels of C18:1, C18:2, and C18:3 with higher bovine blood contents. The amino acid content generally increased with higher blood proportions. This study highlights the bioconversion potential of BSFL for bovine blood and underscores the impact of protein, lipid, and sugar concentrations in feed on BSFL growth. These findings provide valuable insights for utilizing slaughterhouse waste in BSFL rearing, contributing to the development of more sustainable waste management and animal feed production methods.

Biocontrol Strategy of Listeria monocytogenes in Ready-to-Eat Pork Cooked Ham Using Peptic Hydrolysates of Porcine Hemoglobin.

Listeria monocytogenes is a foodborne pathogen that represents a serious concern for ready-to-eat (RTE) meat products due to its persistence in production facilities. Among the different strategies for the control of this pathogen, the use of antimicrobial peptides derived from food by-products, such as slaughterhouse blood proteins, has emerged as a promising biocontrol strategy. This study evaluated for the first time the use of peptic hydrolysates of porcine hemoglobin as a biocontrol strategy of L. monocytogenes in RTE pork cooked ham. Pure porcine hemoglobin (Hb-P) and porcine cruor (P-Cru) were hydrolyzed using pepsin at different temperatures (37 °C for Hb-P and 23 °C for P-Cru) for 3 h. Then, the hydrolysates were characterized in terms of their degree of hydrolysis (DH), peptide population, color, and antimicrobial activity (in vitro and in situ) against three different serotypes of L. monocytogenes. Reducing the hydrolysis temperature of P-Cru by 14 °C resulted in a 2 percentage unit decrease in DH and some differences in the peptide composition. Nevertheless, the antimicrobial activity (in situ) was not significantly impacted, decreasing the viable count of L. monocytogenes by ~1-log and retarding their growth for 21 days at 4 °C. Although the color of the product was visibly altered, leading to more saturated reddish and yellowish tones and reduced brightness, the discoloration of the hydrolysates can be addressed. This biopreservation approach holds promise for other meat products and contributes to the circular economy concept of the meat industry by valorizing slaughterhouse blood and producing new antilisterial compounds.

Processing of slaughterhouse blood for antianemic food products

Currently, rational processing of blood from slaughterhouses remains as a waste fluid in many regions. Traditional approaches to use the blood for food are significantly limited because of specific and non-favorable organoleptic characteristics. Present study provides a comparison of various methods for modifying the red blood cell (RBC) mass of animals and a more in-depth study of acid hemolysis. The solution of ascorbic acid has been proposed as a hemolyzing agent. There has been established experimentally that the addition of equal volumes of RBC and a solution of an ascorbic acid with a concentration of 0.75 mol/dm3 can effectively destroy the stroma more up 90% of red blood cells within 15 minutes. By this, the hemoglobin oxidation degree to methemoglobin is about 50%, which forms the desired color of the resulting hydrolysate. The dry semi-finished product has a neutral odor and brown color with high functional and technological properties. It also contains 0.9% organic iron with good biological value. Thus, the study shows that blood products can effectively use in various foods such as meat products, and also as a dietary supplement for various proposes. Consumption of these products has potent positive effect on hemoglobin levels and it is recommending for people with iron deficiency anemia.

A Review of Slaughterhouse Blood and its Compounds, Processing and Application in the Formulation of Novel Non-Meat Products

Animal blood has become of growing interest, and its functional and nutritional properties are being exploited. In recent years, several research papers related to the application of blood in food products have been published. The purpose of this review is to describe animal blood, its chemical composition, sampling, processing, preservation, and its application in various non-meat products. Bovine, pig and guinea pig blood has been used in the formulation of different foods such as chocolate, cookies, sausages, drinks, gummies, extruded products and consumed directly as a nutritional supplement, the compounds of interest being heme iron from hemoglobin, blood plasma and serum, bioactive proteins and peptides. However, animal blood residues have a high microbial load that is controlled in slaughterhouses. Likewise, the use of this by-product has shown an increase in hemoglobin levels in pregnant mothers and children with anemia who consume it. These fortified foods were high in protein and iron. The use of blood in different food matrices is a potential alternative to improve its nutritional quality, in addition to helping to reduce the levels of malnutrition and anemia in people.

Flocculation efficiency of phosphorylated hemoglobin on kaolin and hematite systems

AbstractHemoglobin recovered from slaughterhouse blood has proven to be an effective flocculant of negatively charged particulate contaminants, but it is ineffective against positively charged contaminants. Phosphorylation is useful for modifying proteins to increase the number of negatively charged sites. Dry‐heat phosphorylation and chemical phosphorylation were applied to hemoglobin. The kaolin/hematite clarification efficiencies of modified hemoglobin at different dosages and pH values were determined. ζ‐potential and total phosphorus content were also measured. Chemical phosphorylation was generally more effective than dry heat phosphorylation at achieving the desired modification of properties; it produced modified hemoglobin (CPhosHb) with higher phosphorus content and lower isoelectric point, and it had greater efficiency in flocculating hematite suspensions. At the optimal dosage of 5 mg/g hematite, treatment with CPhosHb resulted in a 99% turbidity reduction in the hematite suspension after 24 h. When 500 mM calcium chloride was applied to CPhosHb, it exhibited a positive charge in the overall pH range and was capable of clarifying suspensions of negatively charged kaolin particles at low doses. From these results, the effectiveness of chemical phosphorylation on hemoglobin is demonstrated and CPhosHb can be used as a flocculant of either negatively charged or positively charged contaminants in wastewater.

Functional gels from bovine blood proteins as fat substitutes and potential carriers of heme iron

We evaluated technological and physicochemical properties and infrared spectra of heat-induced hydrogels (HGs) and emulgels (EGs) obtained from a composite gellant (DFM) of freeze-dried bovine plasma and red cell fraction. Results showed that 10% W/W of DFM is enough to produce gels of adequate self-support, with syneresis ranging from 3 to 11% and 6–13%, for HGs and EGs, respectively. The color differences were perceptible in all cases, and the opacity related to the assembly of the networks increased with the amount of DMF in both gels. Heat-induced gelation led to heme iron (HFe) retention efficiency higher than 89.45 ± 0.19%. Also, lipid oxidation levels in the EGs were lower than the threshold value. We concluded that 10% of DMF allowed obtaining appropriate gels for their use as fat substitutes and potential heme iron vehicles in food products. However, bioavailability studies are required to better understand their behavior under digestive conditions. Industrial relevanceCurrently, a low proportion of slaughterhouse blood is aimed at human consumption. Plasma is the most widely used fraction of bovine blood, while the red cell fraction has little application for human consumption, despite its incredible nutritional value. Therefore, the results of this study represent a promising alternative for the use of the red cell fraction, which could be applied to the preparation of highly absorbed iron-enriched foods, useful in the prevention or treatment of iron-deficiency anemia. The iron-enriched gels of our study could be used as fat substitutes in the design of low-fat or improved lipid-profile food matrixes (including baked goods and meat products), which implies adding value to a by-product of slaughterhouses and a potential benefit for the industry of reformulated food products.

Comparison of Functional Properties of Blood Plasma Collected from Black Goat and Hanwoo Cattle.

Slaughterhouse blood is a by-product of animal slaughter that can be a good source of animal protein. This research purposed to examine the functional qualities of the blood plasma from Hanwoo cattle, black goat, and their hydrolysates. Part of the plasma was hydrolyzed with proteolytic enzymes (Bacillus protease, papain, thermolysin, elastase, and α-chymotrypsin) to yield bioactive peptides under optimum conditions. The levels of hydrolysates were evaluated by 15% sodium dodecyl sulfate polyacrylamide gel electrophoresis. The antioxidant, metal-chelating, and angiotensin I-converting enzyme (ACE) inhibitory properties of intact blood plasma and selected hydrolysates were investigated. Accordingly, two plasma hydrolysates by protease (pH 6.5/55°C/3 h) and thermolysin (pH 7.5/37°C/3-6 h) were selected for analysis of their functional properties. In the oil model system, only goat blood plasma had lower levels of thiobarbituric acid reactive substances than the control. The diphenyl picrylhydrazyl radical scavenging activity was higher in cattle and goat plasma than in proteolytic hydrolysates. Ironchelating activities increased after proteolytic degradation except for protease-treated cattle blood. Copper-chelating activity was excellent in all test samples except for the original bovine plasma. As for ACE inhibition, only non-hydrolyzed goat plasma and its hydrolysates by thermolysin showed ACE inhibitory activity (9.86±5.03% and 21.77±3.74%). In conclusion, goat plasma without hydrolyzation and its hydrolysates can be a good source of bioactive compounds with functional characteristics, whereas cattle plasma has a relatively low value. Further studies on the molecular structure of these compounds are needed with more suitable enzyme combinations.

Impact of Pulsed Electric Fields and pH on Enzyme Inactivation and Bioactivities of Peptic Hydrolysates Produced from Bovine and Porcine Hemoglobin.

The production of bioactive peptides from hemoglobin via peptic hydrolysis is a promising alternative to valorizing slaughterhouse blood proteins. Nevertheless, it has some limitations such as low yield, high cost of enzymes, and the use of chemical reagents. The latter is aggravated by the pH increase to inactivate the enzyme, which can affect the bioactivity of the peptides. Thus, this study aimed to evaluate the effect of pulsed electric fields (PEF) on the pepsin inactivation and biological activities (antimicrobial and antioxidant) of hemoglobin hydrolysates. Bovine (Hb-B) and porcine (Hb-P) hemoglobin were hydrolyzed with pepsin for 3 h and treated with PEFs to inactivate the enzyme. The degree of hydrolysis (DH) did not show significant changes after PEF inactivation, whereas peptide population analysis showed some changes in PEF-treated hydrolysates over time, suggesting residual pepsin activity. PEF treatments showed no significant positive or negative impact on antimicrobial and antioxidant activities. Additionally, the impact of pH (3, 7, and 10) on bioactivity was studied. Higher pH fostered stronger anti-yeast activity and DPPH-scavenging capacity, whereas pH 7 fostered antifungal activity. Thus, the use of hemoglobin from the meat industry combined with PEF treatments could fit the circular economy concept since bioactive peptides can be produced more eco-efficiently and recycled to reduce the spoilage of meat products. Nevertheless, further studies on PEF conditions must be carried out to achieve complete inactivation of pepsin and the potential enhancement of peptides' bioactivity.

Modulation of Functional Characteristics of Mesenchymal Stromal Cells by Acellular Preparation of Porcine Hemoglobin

Exploring the potential usage of the acellular preparation of porcine hemoglobin (PHb) isolated from slaughterhouse blood as a cell culture media component, we have tested its effects on the functional characteristics of stromal cells of mesodermal origin. Human peripheral blood mesenchymal stromal cells (PB-MSCs) were used in this study as a primary cell model system, along with three mouse cell lines (ATDC5, MC3T3-E1, and 3T3-L1), which represent more uniform model systems. We investigated the effect of PHb at concentrations of 0.1, 1, and 10 μM on these cells’ proliferation, cycle, and clonogenic and migratory potential, and found that PHb’s effect depended on both the cell type and its concentration. At the lowest concentration used (0.1 μM), PHb showed the least evident impact on the cell growth and migration; hence, we analyzed its effect on mesenchymal cell multilineage differentiation capacity at this concentration. Even under conditions that induce a specific type of MSC differentiation (cultivation in particular differentiation media), PHb modulated chondrogenic, osteogenic, and adipogenic differentiation, making it a potential candidate for a supplement of MSC culture. Through a model of porcine hemoglobin, these findings also contribute to improving the knowledge of extracellular hemoglobin’s influence on MSCs >in vivo.

The porcine abattoir blood model-Evaluation of platelet function for in-vitro hemocompatibility investigations.

The major obstacle of blood-contacting medical devices is insufficient hemocompatibility, particularly thrombogenicity and platelet activation. Pre-clinical in-vitro testing allows for the evaluation of adverse thrombogenicity-related events, but is limited, among others, by the availability and quantity of human blood donations. The use of animal blood is an accepted alternative for several tests; however, animal and particularly abattoir blood might present species-specific differences to human blood as well as elevated blood values, and pre-activated platelets due to stressed animals and non-standardized blood collection. To this end, we investigated porcine abattoir blood in comparison to human donor blood with the focus on platelet pre-activation and remaining activation potential. By means of light transmission aggregometry, aggregation kinetics of platelet rich plasma after stimulation with three different concentrations of each adenosine diphosphate (ADP) (5µM, 10µM, 20µM) and collagen (2.5µg/ml, 5µg/ml, 10µg/ml) were monitored. The activation with collagen revealed no significant differences in platelet behavior of the two species. In contrast, stimulation with ADP resulted in a lower maximum aggregation and a high disaggregation for porcine abattoir blood. The latter is a species-specific phenomenon of porcine platelets. Variations within each study cohort were comparable for human and abattoir pig. The similarities in platelet activation following collagen stimulation and the preservation of the porcine-specific reaction to ADP prove a general functionality of the abattoir blood. This finding provides a first step towards the complete validation of the porcine abattoir blood model.

Effect of pH on the Antimicrobial Activity and Peptide Population of Pepsin Hydrolysates Derived from Bovine and Porcine Hemoglobins

Slaughterhouse blood is considered a valuable by-product of the meat industry that is mainly derived from the slaughter of cattle and pigs. Its cruor fraction is mainly constituted of hemoglobin, which has been widely described as an important source of several antimicrobial peptides that can be released by hydrolysis with pepsin. Despite the high sequence similarity between bovine (Hb-B) and porcine (Hb-P) hemoglobins, the release of antimicrobial peptides may be affected by varying hydrolysis conditions. This study presents, for the first time, the impact of pH (pH 2, 3, 4, and 5) on the antimicrobial peptide population of hydrolysates derived from the main hemoglobin sources by using pepsin (bovine and porcine). In the same way, their antibacterial, antifungal, and antiyeast activities are compared, as well as their type of mechanism of action (static or cidal effect). These characteristics have not been described previously in the literature. A total of 29 peptides from Hb-B and 35 peptides for Hb-P with potential antimicrobial peptides were identified by reversed-phase ultrahigh-performance liquid chromatography with tandem mass spectrometry (RP-UPLC–MS/MS) and bioinformatics tools. Similarities in the peptide population between Hb-B and Hb-P hydrolysates were observed by PCA, mainly in the enzymatic hydrolysis at pH 2 and pH 3. Both bovine and porcine hydrolysates produced at pH 2 and pH 3 showed antibacterial activity against L. ivanovii (MIC = 0.62–1.25 mg·mL–1) and antiyeast activity against R. mucilaginosa (0.31–1.25 mg·mL–1). Conversely, only antifungal activity against M. racemosus in the porcine hydrolysate at pH 3 was observed (1.25 mg·mL–1). This study confirms the similarities of Hb-B and Hb-P in terms of peptide profiles and antimicrobial activity, which indicates they are suitable sources of antimicrobial peptides with antibacterial, antifungal, and antiyeast activities that could be employed in the preservation of food products.

Toward circular economy by electrodialysis with ultrafiltration membrane: from slaughterhouse blood to natural meat preservative

Toward circular economy by electrodialysis with ultrafiltration membrane: from slaughterhouse blood to natural meat preservative

Storability of porcine blood in forensics: How far should we go?

Previous studies on the storability of porcine blood for bloodstain pattern analysis (BPA) focused on abattoir blood only and did not include measurements of viscoelasticity. Although known to provoke echinocyte formation, EDTA is widely used for BPA issues. We compared ageing samples taken from live pigs with abattoir blood and detected considerable differences in hematocrit (HCT), total protein and shear viscosity that even worsened with time. Upon storage, high shear viscosity continuously increased, resulting in a partial loss of the typical shear thinning property of blood. Furthermore, we explored CPDA-1, the gold standard in preserving red blood cells (RBCs), for storage of forensic samples. We found it to be a superior choice for anticoagulation, as the rise of high shear viscosity was attenuated compared to EDTA. When performing oscillation measurements, we found a sudden change of viscoelasticity of blood after 22 days, providing a cut-off for storage time. To highlight the importance of hematological and hemorheological changes upon cold storage, we performed simple drip pattern experiments. These tests revealed a tendency to smaller stain diameters and higher numbers of satellite spatter. While this contradicts expectations from elevated viscosity values, we associate this trend to microscopic inhomogeneities due to storage. We recommend CPDA-1 for prolonged storage of BPA samples and suggest the use of comprehensive test protocols including viscoelasticity for determination of the maximum shelf life of pig blood.

A New Technique for Improved Use of Thermal Energy from Waste Effluents

Energy sustainability and environmental protection in general are at the heart of engineering and industry discussions. Countless efforts have been devoted to improving the energy efficiency of industrial processes and specifically to harnessing their waste energy sources. One such source is waste from agro-industrial processes, which is frequently characterized by increased temperatures and high polluting potential. There are multiple available choices for exploiting energy from such waste, but this paper proposes a new alternative technique that substantially improves the efficiency. Based on the technology of leveraging a hot liquid effluent for heating a process fluid, this system introduces a third liquid to be revalorized by drying that is placed in between the hot and cold liquids. By adding stirrers inside the heat exchanger, the thermal resistance of the third fluid is reduced to a negligible level. Thus, this system has almost the same advantages as the previous one, but with the added benefit that it allows drying of a third fluid. One of the specific applications of this proposed technology is using heat from waste effluents to obtain dried food products. In the present work, it was used to dry slaughterhouse blood to obtain so-called “blood meal”, a product with a high added value that is used as pet food or organic fertilizer, and also has many other industrial applications. As shown here, the new technique outperforms existing alternatives in terms of energy efficiency and economic profitability.

Extracellular xenogeneic hemoglobin suppresses the capacity for C2C12 myoblast myogenic differentiation

Functional characteristics of satellite cells (SCs) that act as myogenesis initiators and have emerged as a promising target for cell therapy, are dependent on their microenvironment. The aim of this study was to investigate the effect of cell-free hemoglobin, as a part of the microenvironment of SCs, on their functional characteristics. The C2C12 cell line served as the experimental model of SCs; hemoglobin isolated from porcine (PHb) and bovine (BHb) slaughterhouse blood served as the experimental model for extracellular hemoglobin. The proliferation rate of C2C12 cells was assessed by the MTT test, migration capacity by the scratch assay, and myogenic differentiation capacity by histochemical staining and RT-PCR analysis of the expression of genes specific for myogenic lineage. The effect of hemoglobin on the proliferation and migration of C2C12 cells was dependent on its concentration and the animal species it was isolated from, but the effect of BHb was more prominent. Both PHb and BHb decreased the expression levels of myogenin and muscle specific creatine kinase at a 10 ?M concentration. While PHb had no effect on the morphometric parameters of C2C12 myotubes, BHb modified the area and length of C2C12 myotubes cultivated in DMEM/2% horse serum and DMEM/10% fetal calf serum. While PHb and BHb had no effect on heme oxygenase 1 (Hmox1) expression, they stimulated the expression of hypoxia-inducible factor 1-alpha (Hif1?) at a concentration of 10 ?M. The mainly inhibitory effect of cell-free hemoglobin on myogenic differentiation suggests that it could be a relevant factor in the outcome of cell therapy of muscle injury.

Miniaturized Test Loop for the Assessment of Blood Damage by Continuous-Flow Left-Ventricular Assist Devices.

Although the hemocompatibility of left-ventricular assist devices (LVADs) has continuously improved, assessment of hemolysis remains mandatory in pre-clinical testing. The ASTM-F1841 has standardized this assessment since 1997. However, the recommended usage of fresh, non-pooled human blood is hardly feasible with the test loop volume specified therein, when testing the device under test versus a predicate device as required by the international standard 10993-4. In this study, we compared ASTM-conforming (ASTM) and downscaled (mini) test loops with a one-third priming volume for the assessment of blood damage at the ASTM operating point. Blood damage was assessed for HeartMate 3 and BPX-80 in 6 experiments with heparinized porcine slaughterhouse blood for 6h. We analyzed plasma free hemoglobin (pfHb), von Willebrand factor (vWF) concentration and collagen-binding functionality and calculated indices of hemolysis and vWF-ratios. The mini test loops provided significantly higher pfHb increase and consistently stronger vWF-ratio decrease and yielded a significantly better differentiation of the pumps. Interestingly, indices of hemolysis were generally lower in the mini set-up, indicating less adverse effects by the mini loop itself. Thus, we propose our mini test loop as suitable tool for clinically relevant standardized assessment of blood damage by future LVADs with single-donation human blood.

Native bovine hemoglobin reduces differentiation capacity of mesenchymal stromal cells in vitro

We have tested in vitro effects of hemoglobin from bovine slaughterhouse blood (BHb) on stromal cells of mesodermal origin, with an aim to explore its use as a component of cell culture media. Human peripheral blood mesenchymal stromal cells (PB-MSCs) and three mouse cell lines (ATDC5, MC3T3-E1 and 3T3-L1) were employed to study BHb effects on their growth and migration. The cells multilineage differentiation capacity in the presence of BHb was evaluated after induced differentiation, by histochemical staining and by RT-PCR analysis of the expression of genes specific for chondrogenic, adipogenic and osteogenic lineages. The effects of BHb on the cell proliferation and motility were dependent on both, cell type and BHb concentration (0.1 μM, 1 μM and 10 μM). In the lowest concentration (0.1 µM) BHb showed the least prominent effect on the cell proliferation and migration. In this concentration BHb reduced the differentiation capacity of all tested cells and its effect was dependent of composition of induction medium and the culture period. Obtained data suggest that BHb has the potential to be used as a component of cell culture media through maintaining proliferation and reducing differentiation capacity of mesenchymal stromal cells.

Maltose-mediated long-term stabilization of freeze- and spray- dried forms of bovine and porcine hemoglobin

Slaughterhouse blood represents a valuable source of hemoglobin, which can be used in the production of heme-iron based supplements for the prevention/treatment of iron-deficiency anemia. In order to obtain a stable solid-state formulation, the effect of maltose addition (30 %) on the stability and storage of bovine and porcine hemoglobin in powders obtained by spray and freeze-drying (without maltose: Hb; with maltose: HbM) were investigated. Differential scanning calorimetry of spray- and freeze-dried powders indicated satisfying quality of the formulation prepared with maltose on dissolving back into solution. After two-year storage at room temperature (20?5?C) in solid forms, protected from moisture and light, rehydrated spray- and freeze-dried HbM were red, while Hb were brown. Dynamic light scattering showed the presence of native hemoglobin monomers in rehydrated spray- and freeze-dried HbM, but their agglomerates in Hb samples. UV?Vis spectrophotometry confirmed an absence of significant hemoglobin denaturation and methemoglobin formation in HbM freeze-dried powders. In spray-dried HbM, an increased level of methemoglobin was detected. The results confirmed the stabilizing effect of maltose, and suggested its use in the production of long-term stable solid-state formulations of hemoglobin, along with drying processes optimization.

Production of volatile fatty acids from slaughterhouse blood by mixed-culture fermentation

The volatile fatty acid (VFA) production potential from animal blood and the factors affecting this process were investigated in this study. In order to simulate an industrial process different operation modes, batch, fed batch and semi-continuous, were also evaluated. Due to high ammonia concentration in fermentation broth, VFA concentration up to 100 g L−1 was achieved without addition of buffer and methanogen inhibitor. In general, acetic, n-butyric and iso-valeric acids were the most predominant species, although different operational conditions affected the VFA concentration, profile, production rate and yield. The microbial community analysis was conducted on the reactors with the best performance, revealing that 70–90% of the microbial population was from the Clostridiales order with a strong presence from the Sporanaerobacter genus. These results demonstrated the feasibility of a VFA platform bio-refinery using high-protein wastes as substrate via mixed-culture fermentation under non-sterilised conditions.

Treatment of slaughterhouse blood waste using pilot scale two-stage anaerobic digesters for biogas production

Abstract Anaerobic digestion (AD) is an attractive technology for treatment of slaughterhouse blood waste for energy recovery to offset energy used in the slaughterhouse. However, no studies have been conducted at the pilot or full scales using such waste streams as the primary substrate. In this study, three 197-L pilot scale two-stage AD systems, with or without bamboo biocarriers, treating poultry blood waste were evaluated at two organic loading rates (OLRs) (low = 0.4 and high = 0.7 g COD L−1 day−1) under mesophilic condition (26 ± 2 °C) for 260 days. Biocarriers were added to immobilize the microflora and increase cell residence time in the digesters. Results show that the system with biocarriers had methane yield of 192 mL g−1 CODadded and COD removal of 32.4% at the high OLR, and methane yield of 384 mL g−1 CODadded and COD removal of 68.5% at the low OLR, which were significantly higher than those of the system without biocarriers (used as control). Methanobrevibacter and Methanobacterium beijingense were the dominant archaea in the system using biocarriers. It is estimated that 39.7–41.4 kJ can be recovered from the treatment of blood waste from each kg of slaughtered livestock weight using the two-stage AD system.