A fundamental process underlying navigation behaviour, shown to occur in every species tested, uses geometric properties of the environment for location memory and orientation. Here we employ a new method to ask whether this basic geometric orientation ability is innately predisposed in the brain or depends on specific experiences navigating in a geometrically rich environment. Using the newbor...

this study was conducted to evaluate the effects of in ovo feeding of different nutrients on hatchability, initial weight after hatch, growth performance, blood parameters, immune organs and intestinal morphology of broiler chicks. the experiment was conducted in a completely randomized design with 5 treatments, 3 replicates and 16 fertile eggs from ross 308 breeders (28 week old) in each repli...

Differences in the growth rate of male and female offspring can result in different parental rearing costs for sons and daughters. Such differences may also influence the survival chances of male and female offspring when conditions are unfavourable. In birds, hatching asynchrony leads to hierarchical competition for food between siblings. Therefore, the sex of the chick in the first hatched po...

The effects of maternal n-6 and n-3 fatty acid (FA) supplementation on hatched chick tissue FA profile, antioxidant status, and ex vivo eicosanoid production by the cardiac tissue were investigated. Eggs with low, medium, and high levels of n-3 FA were obtained by feeding Cobb breeder hens were fed a corn-soybean meal-based diet containing 3.5% sunflower oil (low n-3), 1.75% sunflower oil plus ...

In birds, yolk androgen concentrations in eggs can increase or decrease over the laying sequence and common hypotheses hold that this serves to favour the competitive ability of either first- or last-hatched chicks depending on the prevailing conditions, and thus promote brood reduction or maintenance of original brood size respectively. Intra-clutch variation of testosterone can shift relative...

From a collection of 2,800 Tn5-TC1 transposon mutants of Salmonella typhimurium F98, 18 that showed reduced intestinal colonization of 3-week-old chicks were identified. The sites of transposon insertion were determined for most of the mutants and included insertions in the lipopolysaccharide biosynthesis genes rfaK, rfaY, rfbK, and rfbB and the genes dksA, clpB, hupA, and sipC. In addition, id...

AIM To investigate the ultrastructural features of the newly hatched larvae of Strongyloides stercoralis in human duodenal mucosa. METHODS Duodenal biopsies from an AIDS patient were studied by transmission electron microscopy to investigate morphology, location, and host-worm relations of newly hatched larvae. RESULTS Newly hatched larvae were found in the Lieberkuhn crypts within the tunn...