Two experiments were conducted to study the effects of red pepper (Capsicum frutescens) powder or red pepper pigment on the performance and egg yolk color of laying hens. In Exp. 1, 210, thirty-wk old, Hy-line Brown laying hens were fed one of seven diets containing 0.3, 0.6, 1.2, 2.0, 4.8 or 9.6 ppm red pepper pigment or 0.3 ppm carophyll red. Each diet was fed to three replicate batteries of ...

Heat stress had a negative effect on laying hens' performance, thus this research was to study the influences of betaine (Bet, 1000 mg/kg betaine), vitamin C (VC, 200 mg/kg ascorbic acid), and vitamin E (VE, 150 mg/kg α-Tocopherol acetate) and their possible combinations on egg production, digestibility of nutrients, plasma hormones and reproductive organs of dual-purpose hens exposed to chroni...

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 deposition of dietary folic acid (FA) into the chicken egg is likely regulated by its conversion to 5-methyltetrahydrofolate (5-MTHF), the predominant form of this vitamin in eggs (>80%). Supplementation of 5-MTHF in the laying hens′ diet may therefore enhance total egg folate concentrations. To this end, a study was conducted using equimolar concentration of either FA or 5-MTHF in diets fe...

Heat stress (HS) is a major problem experienced by the poultry industry during high-temperature conditions. The ability to manage the detrimental effects of HS can be attributed to multiple factors, including genetic background of flocks. The objective of the present study was to determine the genetic variation in HS effects on laying hens' physiological homeostasis. Ninety 28-wk-old White Legh...

The changes in egg production, in broodiness index and in plasma concentrations of LH, prolactin, oestradiol and progesterone were monitored throughout the first period of laying in turkey hens. The hens were subsequently classified according to their ability to express broodiness (33%) and their laying persistency; 25% were out-of-lay by the end of the experiment. A high percentage (67%) of th...

Published data on 4-week-long administration of exogenous thyroxine in broiler breeder hens to decline the cold-induced ascites in their progeny suggest that the long-term maternal hyperthyroidism would affect egg quality characteristics traits in Cobb 500 broiler breeder hens. Seventy 47-w-old broiler breeder Cobb 500 hens (5 replicates and 7 hens each) were assigned in separate cages and allo...

A completely randomized design experiment was conducted to evaluate the effect of feeding different levels (0, 2.5, 5.0, 10.0, 20.0%) of guar meal (GM) in laying hen diets over a 8-wk trial period. A total of 180 Hisex laying hens (25wk old) of similar body weight were randomly distributed among 5 treatments with 6 replicates with 6 hens each. Body weight, body weight gain, egg produced per hen...

Recent studies have indicated that egg yolk immunoglobulins (Ig) can be used for therapeutic purposes and that yolk Ig levels are increased after molting of laying hens. The present study was performed to compare between the effects of two methods of induced molting namely alfalfa and zinc methods on serum and yolk IgY concentrations as well as their effects on the egg quality and immune status...

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...