Chicken egg yolk antibody (IgY) raised against Salmonella enteritidis or Salmonella typhimurium was found in highly specific activity levels by ELISA. S. enteritidis- and S. typhimurium-specific IgY powder, prepared by freeze-drying the egg yolk water-soluble fraction, contained 15.5 and 10.0% of specific IgY, respectively. Anti-S. enteritidis IgY cross-reacted 55.3% with S. typhimurium. The cross-reactivity of anti-S. typhimurium IgY with S. enteritidis was 42.4%. Salmonella-specific IgY was demonstrated to inhibit Salmonella growth in liquid medium. The growth rate of S. enteritidis incubated with S. enteritidis-specific IgY was fourfold less than that of the control group during a 4-to-6-h incubation. Cell counts of S. typhimurium incubated with S. typhimurium-specific IgY were reduced by 1.6 log cfu/mL in comparison to that of the control group after 6 h of incubation. The specific binding activity of IgY was further evaluated by using immunofluorescence and immunoelectron microscopy. It was found that Salmonella-specific IgY could bind to the antigens expressed on the Salmonella surface, resulting in structural alterations of the bacterial surface.

Escherichia coli O157:H7-specific antibodies (immunoglobulin Y [IgY]) were isolated by the waterdilution method from the egg yolk of chickens that were immunized with E. coli O157:H7 whole cells. The specificbinding activity of IgY against E. coli O157:H7 as determined by the enzyme immuno assay showed high levels of activity against bacterial whole cells. IgY binding activity was further demonstrated to have an inhibitory effect on E. coli O157:H7 growth in a liquid medium. The antibacterial function of IgY appeared to result from the interaction of IgY with surface components of E. coli O157:H7, as proven from observation of immunofluorescence and immunoelectron microscopy.

Casein-derived peptides are shown to possess radical scavenging and metal chelating properties. The objective of this study was to evaluate novel anti-inflammatory properties of casein hydrolysates (CH) produced by an eco-friendly process that combines high hydrostatic pressure with enzymatic hydrolysis (HHP-EH). Casein was hydrolysed by different proteases, including flavourzyme (Fla), savinase (Sav), thermolysin (Ther), trypsin (Try), and elastase (Ela) at 0.1, 50, 100, and 200 MPa pressure levels under various enzyme-to-substrate ratios and incubation times. Casein hydrolysates were evaluated for the degree of hydrolysis (DH), molecular weight distribution patterns, and anti-inflammatory properties in chemical and cellular models. Hydrolysates produced using HHP-EH exhibited higher DH values and proportions of smaller peptides compared to atmospheric pressure-enzymatic hydrolysis (AP-EH). Among five enzymes, Fla-digested HHP-EH-CH (HHP-Fla-CH) showed significantly higher antioxidant properties than AP-Fla-CH. The anti-inflammatory properties of HHP-Fla-CH were also observed by significantly reduced nitric oxide and by the suppression of the synthesis of pro-inflammatory cytokines in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) revealed that 59% of the amino acids of the peptides in HHP-Fla-CH were composed of proline, valine, and leucine, indicating the potential anti-inflammatory properties. In conclusion, the HHP-EH method provides a promising technology to produce bioactive peptides from casein in an eco-friendly process.

Four different methods (direct-methylation, saponification, chloroform-methanol extraction, and postextraction saponification) were compared to determine the fatty acids in egg yolk. About 50 mg of pooled egg yolk samples, with C23:0 as an internal standard, was used for all assays. No difference (P > 0.05) was observed among the four methods for C17:0, C18:0, C18:1, C20:1, C18:2n-6, and C22:6n-3 content of egg yolk. Direct saponification resulted in a lower (P < 0.05) content of C14:0, C16:1, C18:3n-3, and C20:4n-6. Fatty acids at less than 0.5%, such as C15:0 and C14:1, were not detectable in the direct saponification method. The total saturated, monounsaturated, or polyunsaturated fatty acids did not differ (P > 0.05) among the four methods. Direct methylation of egg yolk resulted in lower variability than other methods and is fast and economic for determining egg fatty acid composition.

Immunization of chickens with whole bacteria results in the production of antibodies specific to lipopolysaccharide (LPS), a major constituent of the outer membrane of Gram-negative bacteria. However, there is relatively limited information available concerning immune response of purified LPS in this species. In the present study, immune responses were examined in serum and egg yolk from two groups of chickens injected with entire LPS from Escherichia coli and lipid A free LPS from Salmonella typhimurium. The results demonstrated that the increase of antibody activity occurs first in serum, and then in egg yolk with a lag in time of 1 to 3 wk in both groups of chickens. However, the time of elevated levels of antibodies activity was much shorter in chickens immunized with S. typhimurium LPS (< 1 wk) than in those immunized with E. coli LPS (4 wk). A lack of lipid A is the S. typhimurium antigen may be a factor related to this difference.

A study was conducted to determine the effect of dietary alpha-linolenic acid on the fatty acid compositions of egg yolk lipids, tocopherols, and internal quality of raw eggs during storage and the sensory characteristics of hard-boiled eggs from six different laying hen strains. Laying hens (total 300 birds, 72 wk old) from six strains (Rhode Island Red, Barred Plymouth Rock, New Hampshire, Light Sussex, Brown Leghorn, and White Leghorn) were distributed in 12 floor pens (2 pens per strain, 25 birds per pen) with male roosters. One of the pens for each strain was fed with tallow-based control diet and another was assigned with 3% alpha-linolenic acid (LNA) enriched diet with 120 U of mixed tocopherol/kg diet for 3 mo. Ten eggs from each pen were collected every day after 2 wk with the experimental diets, and stored in a cold room at 4 C up to 4 wk. Total lipids, fatty acid compositions, Haugh units, and tocopherols of egg yolk were determined once a week during the 4-wk storage periods. Sensory studies were also conducted using the eggs stored for 2 wk at 4 C. Dietary LNA increased the amount of n-3 fatty acids (6.5%) in total lipid, and over 70% was C18:3n3, and the rest was C22:6n3 (20 to 25%) and C22:5n3 (5 to 10%). Only minor differences in fatty acids among strains were observed. The differences and the changes in tocopherols during storage periods by strain and diet appeared randomly and lacked consistency.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty 35-wk-old chickens, including 10 Single Comb White Leghorn (SCWL) and 10 Rhode Island Red (RIR) hens, were used to examine the effects of egg and yolk weights on egg yolk antibody (IgY) production in the two strains of chickens immunized with BSA. The SCWL chickens had a greater (P < 0.01) percentage hen-day production and greater egg and yolk weights than did the RIR chickens. However, the anti-BSA antibody activities determined by ELISA in the serum and the egg yolk were similar (P > 0.05) between the SCWL and RIR chickens. Similarities between the two strains of hens were also observed in protein and total IgY contents (expressed as the percentage of wet weight of yolk) and the percentage of BSA-specific antibody in the total IgY. It was concluded that both the SCWL and RIR chickens immunized with BSA can produce egg yolk IgY containing similar proportions of BSA-specific antibodies. Therefore, the egg yolk weight and the percentage hen-day production, both of which are greater in the SCWL hens, are considered to be important factors for the efficient production of IgY.

Background: β-lactoglobulin hydrolysates (BLGH) have shown antioxidant, antihypertensive, antimicrobial, and opioid activity. In the current study, an innovative combination of high hydrostatic pressure and enzymatic hydrolysis (HHP–EH) was used to increase the yield of short bioactive peptides, and evaluate the anti-inflammatory and antioxidant properties of the BLGH produced by the HHP–EH process. Method: BLG was enzymatically hydrolyzed by different proteases at an enzyme-to-substrate ratio of 1:100 under HHP (100 MPa) and compared with hydrolysates obtained under atmospheric pressure (AP-EH at 0.1 MPa). The degree of hydrolysis (DH), molecular weight distribution, and the antioxidant and anti-inflammatory properties of hydrolysates in chemical and cellular models were evaluated. Results: BLGH obtained under HHP–EH showed higher DH than the hydrolysates obtained under AP-EH. Free radical scavenging and the reducing capacity were also significantly stronger in HHP-BLGH compared to AP-BLGH. The BLGH produced by alcalase (Alc) (BLG-Alc) showed significantly higher antioxidant properties among the six enzymes examined in this study. The anti-inflammatory properties of BLG-HHP-Alc were observed in lipopolysaccharide-stimulated macrophage cells by a lower level of nitric oxide production and the suppression of the synthesis of pro-inflammatory cytokines. Peptide sequencing revealed that 38% of the amino acids in BLG-HHP-Alc are hydrophobic and aromatic residues, which contribute to its anti-inflammatory properties. Conclusions: Enzymatic hydrolysis of BLG under HHP produces a higher yield of short bioactive peptides with potential antioxidant and anti-inflammatory effects.