This experiment was conducted to evaluate the effects of different levels of Portulaca oleracea (PO),medicinal plant, on performance, egg traits, blood biochemical and immunity parameters of laying hens. One hundred eighty Hi-Line (W-36 strain) mature laying hens 65 up to 76 weeks of age were allotted in a completely randomized design consisting of 5 treatments and 3 replicates (12 birds per re...

Female birds of several species have control over the production of daughters and sons. However, most studies failed to find a relationship between egg size and sex. This is intriguing as adjustment of egg size would constitute a powerful tool for the female to meet different resource demands of the sexes, particularly in size dimorphic species. Our results show that, within clutches of black-h...

Animals should increase their present reproductive output if their chances for future reproduction are low. However, an animal's ability to make this adjustment may be constrained by the physiological mechanisms mediating the response. To examine this hypothesis, I infected 2- and 5-week-old female crickets, Acheta domesticus, with either a pathogen (the bacterium Serratia marcescens) that indu...

Female birds transfer antibodies to their offspring via the egg yolk, thus possibly providing passive immunity against infectious diseases to which hatchlings may be exposed, thereby affecting their fitness. It is nonetheless unclear whether the amount of maternal antibodies transmitted into egg yolks varies with female quality and egg laying order. In this paper, we investigated the transfer o...

Larvae of Anicla infecta (Ochsenheimer, 1816) (Noctuidae) feed upon many grasses and may be harmful to cereals and fodder of economic importance. This study was developed aiming to contribute to knowledge of the biology of this species. The rearing was done in an environmental chamber with the following settings: temperature of 25 +/- 1 degrees C; relative humidity of 70% +/- 10%, and photoperi...

An eight week study was conducted to investigate the effect of inclusion of tomato waste meal in layer diets on laying performance, egg quality and lipid profile as a means to reduce feed cost and pollution. Four laying diets containing tomato waste meal (TWM) at four levels of 0, 3, 6 or 9% were assigned randomly to 4 groups of 40 birds divided among four replicates of 10 birds in each dietary...

The egg-laying rates of hens approximately 470 days of age exhibited a positive correlation to blood melatonin levels. The hens with an egg-laying rate <30%, 30~90% and ≥90% had blood melatonin levels of 5.8 ± 2.6, 74.0 ± 32.9 and 445.9 ± 115.3 ng/ml, respectively. When 10 mg of melatonin was implanted into the hens at 300, 360, 470 and 550 days of age, the egg-laying rates increased 4.63 ± 0.4...