Bovine Plasma Protein Research Articles

Sensory and instrumental textural changes in fillets from Pacú (Piaractus mesopotamicus) fed different diets.

The influence of two dietary treatments on quality properties, like textural parameters, sensory profile, and nutritional composition of Pacú fillets (Piaractus mesopotamicus) were studied. Pacú were fed diets based on plant-meals containing 13 g 100 g-1 fish meal (FMD) or bovine plasma protein concentrate (BPPD) as a complete replacement of fish meal. Harvested fish were filleted, kept frozen at -20C for 7 days before analysis. Chemical composition, amino acid and fatty acid profiles, and CIE-Lab parameters of fillets were measured. Sensory characteristics and texture profile analysis (TPA) were conducted for cooked portions. Average values of TPA hardness, chewiness, and deformability modulus were higher in BPPD samples but there was no significant difference in cohesiveness between samples. In accordance with TPA, higher values of firmness and chewiness as well as less flaky muscle were detected in BPPD samples by sensory panel. However, there was no significant difference in the characteristics associated with higher freshness between samples. Total color difference was lower in BPPD samples. Differences in protein, lipid, ash, and moisture content of FMD or BPPD fillets were not found (p > .05). BPPD fillets showed higher basic and sulfur amino acids. Saturated and polyunsaturated fatty acid contents were higher in FMD fillets than BPPD. However, a significantly higher n-6/n-3 ratio for FMD fillets was observed. The higher values of textural parameters observed for BPPD cooked fillets and the lower n-6/n-3 ratio imply a better sensory and nutritional quality of fillets from fish fed with BPPD. PRACTICAL APPLICATIONS: A complete study is presented on how the source of protein and lipids in feed affect both the sensory profile and the nutritional composition of fillets of Pacú (omnivorous temperate freshwater fish) cultivated in the second stage of fattening. Instrumental texture analysis of the fillets is presented, identifying the indicators that match with sensorial analysis. This analysis can help the industry of aquaculture in the evaluation of new ingredients or diets for fish feeding with impact in the quality of fillets.

Spermine and spermidine act as chemical chaperones and enhance chaperone-like and membranolytic activities of major bovine seminal plasma protein, PDC-109

The major bovine seminal plasma protein, PDC-109, binds to choline phospholipids of the sperm plasma membrane and induces an efflux of cholesterol and choline phospholipids (cholesterol efflux), which is crucial for sperm capacitation. PDC-109 also exhibits chaperone-like activity and protects target proteins against various kinds of stress. Here we show that the polyamines spermine and spermidine, present in high concentration in the seminal plasma of various mammals, increase the ability of PDC-109 to perturb membrane structure as well as its chaperone-like activity. Interestingly, spermine/spermidine alone did not perturb membrane structure but exhibited chaperone-like activity by protecting target proteins against thermal and oxidative stress. When spermine/spermidine was used along with PDC-109, the observed chaperone-like activity was considerably higher than that expected for a simple additive effect, suggesting that PDC-109 and the polyamines act in a synergistic fashion. These results indicate that at the high concentrations present in the seminal plasma spermine/spermidine exhibit a positive modulatory effect on the chaperone-like activity of PDC-109 and may also function as chemical chaperones and protect other seminal plasma proteins from various kinds of stress.

Effect of serine protease inhibitor from squid ovary on gel properties of surimi from Indian mackerel.

Surimi from dark-fleshed fish is prone to degradation of myofibrillar proteins caused by the endogenous proteases, thereby lowering textural property. To tackle the problem, protease inhibitors (egg white, porcine plasma protein, and bovine plasma protein) have been used by the surimi industries. Due to drawbacks of some particular inhibitors (religious constraints, off-white color, off odor, etc.), the novel additives are still in demand. Ovary from squid processing industry, commonly discarded as the waste, can be an alternative natural protease inhibitor, which can improve the gel properties of surimi, especially produced from dark-fleshed fish.

Amino acid supplementation of calf milk replacers containing plasma protein

We determined the effects of calf milk replacers containing 0, 5, or 10% bovine plasma protein (PP), either without or with the supplemental amino acids (AA) Ile and Thr, on growth and health of male Holstein calves (n = 104) for 56 d. Milk replacers were formulated to contain 22% crude protein (CP), 20% fat, and 2.0% Lys. Milk replacers (12.5% solids) were fed at a rate of 1.5% of body weight (BW) on a dry matter basis during wk 1 and 1.75% of BW beginning on d 8. Starter was introduced on d 36 so that effects of PP and AA balance in milk replacers could be isolated. Intake, respiratory scores, and fecal scores were measured daily. Body weight and stature were measured weekly and blood serum samples were obtained during wk 4. Treatments had no effects on intakes of dry matter, CP, or metabolizable energy. During wk 6 and 8, BW was less as PP inclusion increased without AA supplementation compared with the other treatments. In wk 7, calves fed the higher level of PP without AA had lower BW than calves fed either the lower level of PP without supplemented AA or the higher inclusion of PP with supplemented AA. Average daily gain and gain:feed were lowest for calves fed the higher inclusion of PP without supplemented AA; heart girth in wk 7 was smallest for those calves. During the first 21 d, occurrence of scours was greater in calves fed the control milk replacer than in calves fed milk replacers containing the higher inclusion of PP either without or with supplemental AA. Occurrence of scours was also greater for the lower inclusion of PP compared with the higher inclusion of PP when AA were supplemented. Throughout the 56-d experiment, the chance of antibiotic treatment was greater for calves fed the control milk replacer than for all other treatments except the higher inclusion of PP without supplemental AA. Additionally, chance of antibiotic treatment was greater for the higher inclusion of PP without supplemental AA than for other milk replacers with PP. Calves fed treatments with the higher inclusion of PP had fewer days of scours than the controls. All milk replacers with PP, except the milk replacer containing higher PP without supplemental AA, had fewer days of treatment with antibiotics compared to the all-milk control. Inclusion of PP provided similar performance and improved health as long as milk replacers were balanced for Ile and Thr.

Development of fat-reduced sausages: Influence of binary and ternary combinations of carrageenan, inulin, and bovine plasma proteins.

The aim of this work was to study the influence of the binary and ternary combinations of bovine plasma proteins (BPP), inulin (I) and κ-carrageenan (C) in the overall quality of fat-reduced sausages. The influence of these components over different properties (chemical composition, weight loss after cooking, emulsion stability, texture profile and sensory analysis of fat-reduced sausages) was studied and compared against two samples, one without fat reduction and another a fat-reduced sample without addition of texturing agents. In this sense, a full factorial experimental design of two levels with central point was used. The samples containing BPP+I and BPP+C showed a synergy in which the binary combinations presented higher values of moisture and protein content than the samples containing the individual components. The reduction of fat content increases the values of hardness and decreases the values of springiness. Samples with 5% BPP (w/w) and binary combinations of BPP+C and BPP+I had the best stability values (low total fluid loss), demonstrating a significant synergistic effect by combining BPP+C. Similar results were obtained from the study of weight loss after cooking. However, both studies showed a destabilization of the sample BPP+I+C as emulsion stability decreased and weight loss increased after cooking compared to binary combinations ( P < 0.05). Samples with a binary combination of BPP+C and BPP+I do not present a statistically significant difference in the chewiness with respect to a not-fat-reduced commercial sample ( P > 0.05). The less acceptable sample for flavor and texture was the one containing only BPP. However, when BPP combined with I or C, a major acceptability was obtained, demonstrating the synergistic effect of these binary combinations. Therefore, our studies revealed that the binary combinations of BPP with I or C are good alternatives for the development of fat-reduced sausage.

Plasma protein and supplemental isoleucine in milk replacers for dairy calves

We measured the effects of milk replacers containing 0, 33, 66, or 100% of the total replaceable whey protein as bovine plasma protein (PP), without or with Ile supplementation, on the intake, growth, and health of 124 male Holstein calves for 35d. Milk replacers were formulated to contain 18% crude protein and 20% fat, with contents of Lys and Met equalized. When fed to calves at 1.5% of body weight (dry matter basis) under thermoneutral conditions, diets were predicted to allow average daily gains of 0.55kg/d based on metabolizable energy or 0.40kg/d based on apparent digestible protein. Protein supply was more limiting than energy so that differences in protein use could be detected. Dry matter intakes decreased with increased PP, irrespective of Ile supplementation. Final body weights decreased linearly with increasing PP, regardless of Ile supplementation. Average daily gain tended to be affected in a quadratic manner as PP increased, either with or without Ile supplementation; average daily gain and gain-feed ratio were greatest for calves fed diets containing 33% PP and lowest for calves fed 100% PP. The analyzed Lys content in the milk replacers was variable compared with formulated values, and this may have affected growth results. However, the gain-Lys ratio was affected by an interaction of the linear effect of increasing PP with Ile supplementation: it decreased with increasing PP but was improved by supplementation with Ile for calves fed 100% PP. Body measurements decreased with increasing PP inclusion; only decreased heart girth was reversed with Ile supplementation. The lowest and highest inclusion of PP, regardless of Ile supplementation, decreased the occurrence of scours compared with the control diet (all whey protein). Calves fed the lowest and highest PP without Ile supplementation also had fewer total days of scours in the first 21d. In addition, calves fed 100% PP without supplementation of Ile had fewer days of medication compared with the control diet. Even at the highest PP inclusion, average daily gain was minimally affected if Ile was supplemented. Growth rates, gain-feed ratio, and gain-Lys ratio were decreased at higher PP inclusion, but Ile overcame part of the reduction in gain-Lys ratio for 100% PP. Additional titration studies will have to be conducted to determine optimal PP inclusion rates, with a focus on supplementation of potentially limiting essential AA, as well as effects at higher growth rates.

Supplementation of Pork Patties with Bovine Plasma Protein Hydrolysates Augments Antioxidant Properties and Improves Quality.

This study investigated the effects of bovine plasma protein (PP) hydrolysates on the antioxidant and quality properties of pork patties during storage. Pork patties were divided into 4 groups: without butylated hydroxytoluene (BHT) and PP hydrolysates (control), 0.02% BHT (T1), 1% PP hydrolysates (T2), and 2% PP hydrolysates (T3). Pork patty supplemented with PP hydrolysates had higher pH values and lower weight loss during cooking than the control patties. Results showed that lightness and hardness both decreased upon the addition of PP hydrolysates. All samples containing BHT and PP hydrolysates had reduced TBARS and peroxide values during storage. In particular, 2% PP hydrolysates were more effective in delaying lipid oxidation than were the other treatments. It was concluded that treatment with 2% PP hydrolysates can enhance the acceptance of pork patty.

Effect of Bovine Plasma Protein Hydrolysates on the Quality Properties of Cooked Pork Patty

The study investigated the effects of adding bovine plasma protein(PP) hydrolysates on the quality properties of cooked pork patties. Pork patties were prepared as follows: manufactured with pork back-fat(control); replacement of back-fat with 40% olive oil(T1), 40% olive oil and 2% PP hydrolysates(T2), and 40% olive oil and 4% PP hydrolysates(T3). The olive oil modified the fatty acid profiles of the pork patties by lowering the saturated fatty acids(SFAs) percentage. Olive oil and 4% PP hydrolysates addition reduced the level of 2-thiobarbituric acid-reactive substance(TBARS) values in pork patties, compared to the controls. Furthermore, the pork patties with added PP hydrolysates had higher pH values than the control. All samples containing olive oil and PP hydrolysates had increased levels of DPPH radical scavenging activity. In particular, added PP hydrolysates were more effective in increasing antioxidant activity than were the other treatments. Therefore, PP hydrolysates could be used as a natural antioxidative in cooked pork patties.

Antioxidant Effect of Bovine Plasma Proteins Modified via Maillard Reaction on n3 Fortified Beef Patties

This work aimed to develop a healthier meat product, by improving nutritional properties related to lipid profile, using a Maillard reaction product (MRP) obtained from recycling blood from local slaughterhouses as antioxidant. Soybean oil was used as partial fat replacer and the lipid profile was modified as a decrease in the n6/n3 ratio (11.59 to 9.50), and atherogenic and trombogenic index (from 0.42 to 0.27 and 0.94 to 0.56 respectively) was observed. Beef patties were added with two MRP levels (1% w/w and 3% w/w). Patties with no antioxidants were used as control and patties containing 0.01% w/w of butylhydroxyanisole (BHA) were used as reference. Oxidative stability of refrigerated vacuum-packed patties was evaluated during 15 days of storage. Results showed 3% of MRP as the most appropriate concentration to prevent lipid oxidation with inhibition percentages of 75%, and 9 days as the limit time of chilled storage regarding consumers’ perceptions.

Sequestration of bovine seminal plasma proteins by different assemblies of phosphatidylcholine: A new technical approach

Binder of SPerm (BSP) proteins, the main proteins from bovine seminal plasma, are known to partially intercalate into the outer leaflet of the spermatozoa membrane and bind to choline-containing lipids being present therein. This insertion generates a negative effect on semen quality after cryopreservation by inducing an early-stage capacitation of spermatozoa. The assumption of surface properties exhibited by BSP proteins was checked by tensiometry measurements: BSP proteins are highly surface active. This suggests that BSP proteins can reach the interface covered by phospholipids not only by interactions between one and each other but also due to their own surface activity. The insertion of BSP proteins into the lipid domains outer leaflet of spermatozoa was reproduced on a biomimetic system such as Langmuir monolayers. The insertion of BSP proteins can be performed in the compressible fluid domains which contain choline-bearing lipids. Monolayer films were used as well to study the complexation of BSP proteins by two phospholipid assemblies: low density lipoprotein (LDLs) from egg yolk or liposomes produced from egg phospholipids. Irrespective of the phospholipid structure (lipoprotein or liposome), BSP was hindered to alter the structure of the membrane. Only the overall ratio BSP proteins:phosphatidylcholine was important. The difference between the two sequestering agents lies on their surface properties: LDL have a strong tendency to merge with the outer layer whereas liposomes mainly remain in the bulk on the same time scale.

Determination of changes in bovine plasma and milk proteins during naturally occurring Escherichia coli mastitis by comparative proteomic analysis

The aim of this study was to investigate changes in plasma and milk proteins in response to Escherichia coli infection in cows. Plasma and milk were collected from healthy cows, cows suffering from mild E. coli mastitis, and cows suffering from severe E. coli mastitis. Protein composition was examined by two-dimensional gel electrophoresis coupled with mass spectrometry. Plasma haptoglobin and α-1 acid glycoprotein demonstrated greater expression in mastitic cows compared with controls, but there were no difference between mildly and severely mastitic cows. Milk from mildly mastitic cows showed increased albumin and casein variants. Severely mastitic cows showed lower casein levels and increased anti-microbial and acute phase proteins. Milk α-1 acid glycoprotein and cathelicidins were associated with severe mastitis. A greater number of β-casein fragments that corresponded to β-casein isoforms were found in milk from mildly mastitic cows. These results suggest that caseins levels decreased and the concentrations of anti-microbial and acute phase proteins increased corresponding to the degree of E. coli mastitis. Nevertheless, further studies are needed to determine whether cathelicidin could serve as a diagnostic marker for mastitis.

Altered Expression Pattern of Major Seminal Plasma Protein Genes in Seminal Vesicles of Water Buffalo (Bubalus bubalis)

The binder of sperm proteins (BSP) are secretary products of seminal vesicles. Secretions from the seminal vesicles contribute more to seminal plasma which determine the quality of the semen. The concentration of BSPs in seminal plasma has been negatively correlated with cryopreservation. An analysis of expression profile of seminal plasma proteins could be critical for better freezability of semen. Present study was carried out to assess the expression levels of major seminal plasma protein genes viz., BSP1, BSP3 and BSP5 from seminal vesicles of water buffalo using Real Time PCR. The study consisted of identification of a suitable reference gene in seminal vesicles followed by the expression analysis of major bovine seminal plasma protein (BSP) genes. The most stable reference gene among the three (glyceraldehyde 3-phosphate dehydrogenase, ribosomal protein S15a (RPS15a) and beta-actin), was found to be RPS15a and therefore, was used for normalization of target gene expression. Data analysis of major BSPs showed highest relative expression of BSP3 followed by BSP1 and BSP5. The ratio of relative expression of BSP1:BSP3:BSP5 was 10:18:1. The results from the study also showed an altered expression pattern of major BSP genes in buffalo seminal vesicles. Thus, it can be concluded that the altered expression of these genes at mRNA level would also be reflected at protein level in the seminal plasma. This could be one of the probable reasons for poor freezability of buffalo semen as compared to cattle and the finding helps in designing better cryopreservation strategies for buffalo semen.

Effect of Mg2+ binding on transmission of bovine serum albumin (BSA) through ultrafiltration membranes

Protein fractionation by membrane technology has many advantages for separations, in comparison with conventional methods. In this paper, the influence of different type and concentration of two electrolytes: NaCl and MgCl2 on buffer capacity and hydrodynamic radius of bovine plasma proteins were analyzed as a way to improve protein separation by cross-flow ultrafiltration. A tubular ceramic membrane with 0.2μm pore size was used. The evolution of permeate flux and BSA transmission was determined at 25°C and transmembrane pressure range of 0.2–1.4bar. The membrane fouling was evaluated through the resistance model application, identifying the operational conditions of the highest BSA transmission through the membrane. In this regard, it was demonstrated that the effective radius of the protein and its buffering capacity were affected by the use of MgCl2 at 0.006 (w/v), which caused conformation changes in the protein structure resulting in a less resistance to transport.

Optimization of hydrolysis conditions for bovine plasma protein using response surface methodology

The purpose of this study was to establish optimal conditions for the hydrolysis of bovine plasma protein. Response surface methodology was used to model and optimize responses [degree of hydrolysis (DH), 2,2-diphenyl-1-picrydrazyl (DPPH) radical-scavenging activity and Fe2+-chelating activity]. Hydrolysis conditions, such as hydrolysis temperature (46.6–63.4°C), hydrolysis time (98–502min), and hydrolysis pH (6.32–9.68) were selected as the main processing conditions in the hydrolysis of bovine plasma protein. Optimal conditions for maximum DH (%), DPPH radical-scavenging activity (%) and Fe2+-chelating activity (%) of the hydrolyzed bovine plasma protein, were respectively established. We discovered the following three conditions for optimal hydrolysis of bovine plasma: pH of 7.82–8.32, temperature of 54.1°C, and time of 338.4–398.4min. We consequently succeeded in hydrolyzing bovine plasma protein under these conditions and confirmed the various desirable properties of optimal hydrolysis.

Effect of Bovine Plasma Protein on Autolysis and Gelation of Protein Extracted from Giant Squid (Dosidicus gigas) Mantle

The effect of bovine plasma protein (BPP) on the inhibition of autolytic activity and its effect on the gelling properties of a protein concentrate (PC) obtained from jumbo squid (Dosidicus gigas) mantle were investigated. Sols and gels were prepared from the PC by adding different amounts of BPP (0, 1, and 2%). Dynamic oscillatory measurements indicated that systems with 1% BPP had a higher elastic modulus (G′), in which hydrophobic interactions were favored. Concerning the technological and textural quality of the gels, BPP caused a greater water holding capacity (WHC), force, cohesiveness, and elasticity, probably due to improvement of the electrostatic and hydrophobic interactions during gel formation. Scanning electron microscopy (SEM) allowed visualization of the formation of more rigid and ordered gels with less porosity when BPP was added. Therefore, the addition of BPP improved the gelling capacity of proteins extracted from giant squid.

Effects of storage time on total protein and globulin concentrations in bovine fresh frozen plasma obtained for transfusion.

To evaluate the effects of storage conditions on total protein (TP) and globulin fractions in fresh frozen bovine plasma units prepared and stored for transfusion, TP and globulin fractions were evaluated in fresh plasma and at 1 month and 6 and 12 months after blood collection in plasma stored at −20°C. Significant differences in concentrations were found in the median concentration of total protein (P = 0.0336), between 0 months and 1 month (P = 0.0108), 0 and 6 months (P = 0.0023), and 0 and 12 months (P = 0.0027), in mean concentration (g/dL) of albumin (P = 0.0394), between 0 months and 1 month (P = 0.0131), 0 and 6 months (P = 0.0035), and 0 and 12 months (P = 0.0038), and beta-2 fraction (P = 0.0401), between 0 and 6 months (P = 0.0401) and 0 and 12 months (P = 0.0230). This study suggests that total gamma globulin concentration in bovine frozen plasma is stable for 12 months at −20°C. Total protein, ALB, and beta-2 fraction have significantly different concentrations (g/dL) when compared to prestorage. This study has shown IgG protein fraction stability in bovine fresh frozen plasma collected for transfusion; therefore, bovine fresh frozen plasma seems to be suitable for the treatment of hypogammaglobulinemia (failure of passive transfer) in calves when stored for 12 months at −20°C.

Protein profile and functionality of spermatozoa from two semen collection methods in Bali bulls

The aim of this study was to evaluate the effect of two semen collection methods (electro-ejaculation [EE] and transrectal massage [RM]) on in vitro sperm functionality and protein composition of seminal plasma in Bali bulls. Ten untrained Bali bulls were selected for semen collection by EE and RM. Parameters analysed were acrosome and plasma membrane integrity, sperm motility (by CASA), normal morphology, functionality (sperm penetration assay), acrosome reaction, total protein content and protein profiles (by 2D-PAGE). Bulls collected by RM had a higher (p<0.05) percentage of spermatozoa with intact acrosome and plasma membrane, functionality and individual motility, and a lower proportion of seminal plasma, total protein content and lower ratio of low molecular weight proteins than those collected by EE. Analysis of 2D-PAGE gel detected about 116 spots in the range of 10–250kDa and isoelectric points (pI) ranging from 3 to 10. Approximately 52% of seminal plasma protein spots were represented by four major protein fractions with molecular weights around 37–45kDa (15.66%), 25–30kDa (12.46%), 14–16kDa (11.73%) and 12–15kDa (11.52%). Ten of the seminal plasma proteins identified by mass spectrometry belonged to major bovine seminal plasma proteins. A very significant finding in this study was related to the two proteins identified, PGK and PLA2, with MW of approximately 37–40 and 50–55kDa and pI of 8.5–8.8 and 5.2–6.0, respectively. These two protein spots can only be detected in the seminal plasma of ejaculates obtained through RM. In conclusion, semen quality as examined by in vitro sperm functionality was found to be better in RM than EE samples after treatment with heparin and calcium ionophore A-23187. In addition some low molecular weight proteins were up-regulated in the seminal plasma obtained from the EE method.

Biophysical characterization of the interaction of O-acylcholines with the major bovine seminal plasma protein, PDC-109.

Thermodynamic parameters characterizing the interaction of O-lauroylcholine (OLC) and O-myristoylcholine (OMC) with PDC-109 have been determined by isothermal titration calorimetric studies. Titration of OLC or OMC with PDC-109 resulted in exothermic peaks, the magnitude of which decreased with subsequent injections, showing saturation of the binding sites at high protein concentration and indicating that the binding process is associated with negative enthalpy change (ΔH° < 0). Association constant (Ka), Stoichiometry (n), and thermodynamic parameters, ΔH°, ΔS° and ΔG° for the binding of OLC to PDC-109 have been obtained at different temperatures, with the values obtained at 25 °C being 5.08 × 105 M−1, 0.47, −4.46 kcal mol−1, 11.13 cal mol−1 K−1 and −7.78 kcal mol−1, respectively. Values of thermodynamic parameters obtained at different temperatures indicate that the binding of PDC-109 to O-lauroylcholine is governed by a negative enthalpy contribution. The interaction of O-lauroylcholine with PDC-109 was also studied by monitoring changes in the protein intrinsic fluorescence emission intensity. The association constant, Ka, for the interaction of PDC-109 with O-lauroylcholine from fluorescence studies at 25 °C was estimated to be 5.46 × 104 M−1, which is somewhat lower than the Ka value determined by ITC. Circular dichroism spectroscopic studies indicate that interaction of O-lauroylcholine with PDC-109 induced changes in the secondary and tertiary structure of PDC-109. Differential scanning calorimetric studies revealed that the thermal unfolding temperature of PDC-109 increases in the presence of OMC, indicating that binding of O-acylcholines stabilizes the protein structure.

Evaluation of feeding spray-dried bovine plasma protein on production performance of laying hens exposed to high ambient temperatures

The purpose of this study was to evaluate feeding 2 levels of spray-dried bovine plasma protein (SDP) on production performance of laying hens subjected to high ambient temperatures. Two groups of 96 Hy-Line W-98 hens (38 wk of age) were housed in each of 2 environmentally controlled chambers. At 40 wk of age, all hens were fed 3 diet treatments consisting of (1) a control diet (0% SDP); (2) the control diet supplemented with 0.75% SDP; and (3) the control diet supplemented with 1.50% SDP. Hens in each chamber (8 cages of 4 hens per cage) were ad libitum fed 1 of each diet for 5 wk. The heat stress (HS) chamber was maintained at 21°C (wk 1), 29°C (wk 2), and 35°C (wk 3 to 5). The thermoneutral chamber was maintained at 21°C during wk 1 to 5. A significant main effect of week was observed for hens maintained in the HS chamber for egg production, egg weight, egg mass, and feed consumption, which resulted in acute heat stress causing a reduction in these parameters. Hens fed the 1.50% SDP diet in the HS chamber produced greater (P < 0.05) egg mass on average than hens fed the control or 0.75% SDP diet (wk 1 to 5). During the second week of acute HS (wk 4), hens fed the control and 1.50% SDP diets had greater (P < 0.05) egg production than those fed the 0.75% SDP diet. During wk 5, hens in the HS chamber that were fed the 1.50% SDP diet produced more (P < 0.05) eggs than those fed the control diet. Therefore, based on the results of this study, acute HS negatively affected short-term production performance. In addition, feeding hens an SDP-supplemented diet may have a slight positive effect on production performance when maintained in acute HS conditions.

Improvement of gluten-free bread properties by the incorporation of bovine plasma proteins and different saccharides into the matrix

The aim of this work was to improve the quality of gluten-free bread, incorporating plasma bovine proteins concentrated by ultrafiltration and freeze-dried with saccharides (inulin and sucrose). The influence of these compounds on textural properties and final bread quality was assessed. The textural studies revealed that with the addition of proteins and inulin, homogeneous and smaller air cells were achieved improving the textural properties while the bread hardness was comparable with breads with gluten. The volume of gluten-free breads increased with increasing proteins and inulin concentrations, reaching a maximum at a protein concentration of 3.5% (w/w). The addition of the enhancers improved moisture retention of the loaves after cooking and an increase of lightness of crumb with respect to the control was observed. The sensory analysis found no statistically significant difference in sensory attributes evaluated with respect to the control, so these ingredients do not negatively affect the organoleptic properties of bread.