1. The aim of this study was to evaluate the tolerance of laying hens for an excessive L-valine (L-val) supply on laying performance, egg quality, serum free amino acids, immune function and antioxidant enzyme activities of laying hens. 2. A total of 720 HyLine Brown hens were allocated to 5 dietary treatment groups, each of which included 6 replicates of 24 hens, from 40 to 47 weeks of age. Gr...

A study was conducted to evaluate the effects of dietary supplementation of phytase B (product of the Aspergillus niger phyB gene expressed in Trichoderma reesei) on feed intake, laying performance, eggshell quality, and on phosphorus and calcium balance in laying hens. Seventy-two, 40 weeks old Hy Line Brown hens were fed for 14 weeks the following four phosphorus-deficient (0.12% nonphytate p...

The effect of supplementing two commercial multienzyme to diets included two barley cultivars (Sararood [71.99%] and Valfajr [66.39%]) on performance, egg quality, and blood parameters of laying hens was investigated in an 8-wk (65 to 73 wk of age) experiment.  The commercial multienzymes were Grindazym™ (with mainly β-glucanase and xylanase activity) and Hemicell® (with mainly β-mannanase acti...

Both epidemiologic analyses and active disease surveillance confirm an ongoing strong association between human salmonellosis and the prevalence of Salmonella enterica subspecies enterica serovar Enteritidis in commercial egg flocks. The majority of human illnesses caused by this pathogen are attributed to the consumption of contaminated eggs. Animal welfare concerns have increasingly influence...

Studies have demonstrated that obesity and osteoporosis are linked disorders in humans. This study examined the hypothesis that excessive lipid consumption affects bone metabolism in laying hens. A total of one hundred 63-wk-old laying hens were randomly divided into 2 treatments and fed either a regular layer diet (control) or a high energy and low protein diet (HE-LP; experimental treatment) ...

The present study aimed to investigate the effects of dietary supplementation of multi-enzyme on productive performance of laying hens fed different levels of safflower meal. A total of 250 Leghorn laying hens (Hy-Line W-36) 47 weeks-old were randomly assigned into 10 experimental treatments with 5 replicates of 5 birds each. Experimental treatments consisted of five safflower meal levels (0.0,...

In this study, we have attempted to understand the effects of taurine on serum and liver concentrations of cholesterol and triglycerides in broiler chickens and mice in the post-absorptive state, and on in vitro protein synthesis in the livers of broiler chickens and laying hens, as well as the effects of taurine on in vivo protein synthesis in the liver of mice. The experimental animals were s...

Data on ammonia (NH3) emissions from pullets (hens <18 weeks of>age) are non-existent despite the large differences in nutritional and environmental conditions between raising pullets and laying hens. Different stocking densities (SDs) in housing the birds may be used according to certain industry guidelines on production; however, information concerning the impact of SD on properties of accumu...

The presence of receptor for arginine vasotocin (AVT) in the vagina of the oviduct of the hen was demonstrated by the use of radioligand binding assays on membrane fractions of the tissue. The binding to [125I]AVT was highly competitive with unlabeled AVT. Scatchard analysis revealed that the binding sites are of a single class. The equilibrium dissociation constant (Kd) was 0.48+/-0.05 nM (x+/...

Propolis is a honeybee product showing several biological properties that enhance the immune response, depending on the concentration and intake period. Because propolis possesses an immunomodulatory action on mammals, the objective of our study was to investigate the effects of propolis on the humoral immune response of laying hens by evaluating antibody production. Laying hens (ISA Brown) wer...