Effects of Dietary Supplementation of Essential Oils, Lysozyme, and Vitamins' Blend on Layer Hen Performance, Viral Vaccinal Response, and Egg Quality Characteristics

Maintaining respiratory tract health is crucial for layers, impacting gut health, laying performance, and egg quality. Viral diseases and standard vaccinations can compromise tracheal epithelium function, leading to oxidative stress. This study assessed the impact of a blend of feed additives, predominantly lysozyme (L), essential oils (EO), and vitamins (VIT) (referred to as L + EO + VIT), on young layers during an oral vaccination schedule. The supplementation significantly enhanced antibody titers for Newcastle Disease Virus (NDV) and Infectious Bronchitis Virus (IBV) after vaccination, trachea functionality and intestinal health in the jejunum, increased egg production, and exhibited a trend toward higher egg weight. Although feed intake showed no significant difference, egg quality remained consistent across experimental groups. Moreover, L + EO + VIT supplementation elevated total phenolic content in eggs, improving oxidative stability in both fresh and stored eggs, particularly under iron-induced oxidation. Notably, it substantially reduced yolk lipid peroxidation and albumen protein carbonyls. In conclusion, water supplementation with L + EO + VIT may enhance humoral immune response to IBV and NDV, positively impacting hen productivity. These findings indicate improved tracheal function and enhanced oxidative stability, emphasizing the potential of this blend in promoting overall health and performance in layers.

Upgrading the Nutritional Value of PKC Using a Bacillus subtilis Derived Monocomponent β-Mannanase

Palm kernel cake (PKC) is an abundant side stream that can only be added to non-ruminant feed in small concentrations due to its content of antinutritional factors, mainly galactomannan, which cannot be digested by non-ruminants. β-mannanases can be added to partially hydrolyze galactomannan to form mannose oligosaccharides, which are known to be prebiotic. We here investigate the action of a β-mannanase from B. subtilis on PKC by colorimetry, NMR and fluorescence microscopy. The amount of mannan oligosaccharides in solution was significantly increased by the β-mannanase and their degree of polymerization (DP) was significantly reduced. There was a dose-response behavior in that larger β-mannanase concentrations increased the amount of soluble mannose oligosaccharides while reducing their average DP. Using confocal immunofluorescence microscopy, solubilization of galactomannan in PKC was clearly visualized. Images show a clear disruption of the cellulose and galactomannan structures of the PKC cell walls. We thus show in this study that using commercial dosages of β-mannanase on PKC can lead to formation of prebiotic compounds. Thus, this study suggests that utilization of PKC in poultry feed formulation might be increased by addition of a β-mannanase and would improve the return on investment.

Short and Medium Chain Fatty Acids and Their Derivatives as a Natural Strategy in the Control of Necrotic Enteritis and Microbial Homeostasis in Broiler Chickens

The use of antibiotic growth promoters (AGPs) has historically been the most important prophylactic strategy for the control of Necrotic Enteritis (NE) caused by some Clostridium perfringens toxin types in poultry. During the last five decades, AGPs have also been supplemented in feed to improve body weight gain and feed efficiency as well as to modulate the microbiome (consisting of microbes and their genes both beneficial and potentially harmful) and reduce enteric pathogens, among other benefits. New regulatory requirements and consumer preferences have led to strong interest in natural alternatives to the AGPs for the prevention and control of illnesses caused by enteric pathogens. This interest is not just focused on the direct removal or inhibition of the causative microorganisms but also the improvement of intestinal health and homeostasis using a range of feed additives. A group of promising feed additives is short- and medium-chain fatty acids (SCFA and MCFA, respectively) and their derivatives. The use of SCFA and MCFA, including butyric, caproic, caprylic, capric, and lauric acids, has shown strong effects against NE in broilers both at experimental and commercial levels. These fatty acids also benefit intestinal health integrity and homeostasis. Other effects have also been documented, including increases in intestinal angiogenesis and gene expression of tight junctions. Chemical modifications to improve stability and point of release in the intestine have been shown to improve the efficacy of SCFA and MCFA and their derivatives. The aim of this review is to give an overview of SCFA, MCFA and their derivatives, as an alternative to replace AGPs to control the incidence and severity of NE in poultry.