156 Effect of Anti-yeast on Sugarcane Silage Gas Production

Although sugarcane produces a large amount of energy per hectare, its ensiled storage leads to losses, which makes it one of the most expensive options for animal feeding. These losses occur due to fermentation of sugars and organic acids by yeasts, producing alcohol and gas. Inoculants containing Lactobacillus buchneri increase acetic acid production, which has effect against yeast. In this study, we produced egg yolk antibodies (IgY) against yeasts that ferment lactate (Candida glabrata, Pichia kudriavzevii, and Pichia manshurica) and sugar (Saccharomyces cerevisiae, Torulospora delbrueckii, Schizosaccharomyces pombe and Debaryomyces etchellsii) isolated in sugarcane silage. Shortly before ensiling, doses of 0, 175, 350, and 700 g/t IgY, and Lactobacillus buchneri were applied to chopped forage. Gas losses were calculated using experimental silos in triplicate, according to the equation: G = (PCf - PCa)/(MFf) × 100, in which: G = gas losses (kg/t); PCf = weight of full silo (equipped with a Bunsen valve to allow gas outflow) at sealing (kg); PCa = weight of full bucket at opening (kg); MFf = forage mass at sealing (kg). The data were analyzed as a completely randomized design and submitted to analysis of variance and regression using the SAS (SAS, 1998), which was chosen because of the significance of the regression parameters, tested by Tukey’s test (P < 0.05) and the values of the coefficients of determination. Thirty days after sealing the L. buchneri inoculant and doses of 350 and 700 g/t IgY promoted less gas losses than control that had no any product (12.74; 15.59 and 15.28 versus 27.74, respectively, P < 0.05) and the L. buchneri did not differ from IgY doses. The gas losses decreased quadratically with the anti-yeast addition, estimating maximum of 530 g/t fresh forage. We conclude that anti-yeast use reduces gas production during fermentation. With continuity of this research, we may obtain a roughage with higher nutritional value, as its mode of action in yeast control does not involve consumption of sugars or organic acids.

Evaluation of the Immunogenic Response of a Novel Enterobactin Conjugate Vaccine in Chickens for the Production of Enterobactin-Specific Egg Yolk Antibodies

Passive immunization with specific egg yolk antibodies (immunoglobulin Y, IgY) is emerging as a promising alternative to antibiotics to control bacterial infections. Recently, we developed a novel conjugate vaccine that could trigger a strong immune response in rabbits directed against enterobactin (Ent), a highly conserved siderophore molecule utilized by different Gram-negative pathogens. However, induction of Ent-specific antibodies appeared to be affected by the choice of animal host and vaccination regimen. It is still unknown if the Ent conjugate vaccine can trigger a specific immune response in layers for the purpose of production of anti-Ent egg yolk IgY. In this study, three chicken vaccination trials with different regimens were performed to determine conditions for efficient production of anti-Ent egg yolk IgY. Purified Ent was conjugated to three carrier proteins, keyhole limpet hemocyanin (KLH), bovine serum albumin (BSA) and CmeC (a subunit vaccine candidate), respectively. Intramuscular immunization of Barred Rock layers with KLH-Ent conjugate four times induced strong immune response against whole conjugate vaccine but the titer of Ent-specific IgY did not change in yolk with only a 4 fold increase detected in serum. In the second trial, three different Ent conjugate vaccines were evaluated in Rhode Island Red pullets with four subcutaneous injections. The KLH-Ent or CmeC-Ent conjugate consistently induced high level of Ent-specific IgY in both serum (up to 2,048 fold) and yolk (up to 1,024 fold) in each individual chicken. However, the Ent-specific immune response was only temporarily and moderately induced using a BSA-Ent vaccination. In the third trial, ten White Leghorn layers were subcutaneously immunized three times with KLH-Ent, leading to consistent and strong immune response against both whole conjugate and the Ent molecule in each chicken; the mean titer of Ent-specific IgY increased approximately 32 and 256 fold in serum and yolk, respectively. Consistent with its potent binding to various Ent derivatives, the Ent-specific egg yolk IgY also inhibited in vitro growth of a representative Escherichia coli strain. Together, this study demonstrated that the novel Ent conjugate vaccine could induce strong, specific, and robust immune response in chickens. The Ent-specific hyperimmune egg yolk IgY has potential for passive immune intervention against Gram-negative infections.

Egg yolk antibodies (IgY) and its relevance in animal and human health-An updated review

Egg yolk represents an alternate source of antibody and provides some advantages over mammalian serum immunoglobulins. The principal immunoglobulin in avian blood is Immunoglobulin Y (IgY) and is transferred to egg yolk and then to their offspring and thus makes it possible for the non-invasive harvesting of antibodies in higher amount from eggs. Moreover, due to the structural differences and phylogenetic variations, IgY is more acceptable than mammalian antibodies for diagnostic purposes, as it does not interfere with mammalian antibodies and shows greater avidity for proteins retained in mammals. As a therapeutic and diagnostic tool, IgY has wide application in animal and human health. The emergence of drug resistance organisms causing respiratory tract infections is a critical problem for the health care system worldwide. Passive immunization is a potential alternative for this. Recent studies on the diagnosis and therapeutic effects of IgY against SARS-CoV-2 indicates the importance of this technique in the present context. This review refers to the use of IgY antibodies from chicken egg yolks against the infection caused by bacteria, viruses (including SARS-CoV-2) and parasites in human beings and in animals in addition to its use in food preservation, anti tumour and anti allergic activities. Keywords: Egg yolk antibodies (IgY); human health; SARS-CoV-2; Egg yolk