The present research was aimed to study the effects of different sources of carotenoids and their varying concentrations on the reproductive functions of goldfish. The study was carried out in seven treatments with three replicates at the Bony Fish Hatchery Complex (Rasht, Iran) from December 2011 to May 2012. Experimental diets containing 50, 100, and 150 mg kg-1 astaxanthin and 50, 100, and 1...

The trade-off between reproductive investment and migration should be an important factor shaping the evolution of life-history traits among populations following their radiation into habitats with different migratory costs and benefits. An experimentally induced difference in migratory rigor for families of chinook salmon (Oncorhynchus tshawytscha), of approximately 86 km and 413 m elevation, ...

Adult great spotted cuckoos Clamator glandarius damage the eggs of their magpie Pica pica host without removing them from the nest or eating them but by producing the death of the embryo. Observations as well as experiments were used to test several predictions of two different possibilities: great spotted cuckoo egg-damaging behavior is a parasitic tactic resulting from a direct selection proc...

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...

Egg shell quality and egg internal quality are of major importance to the egg industry worldwide. This review covers the formation of the hen’s egg and ways of measuring egg shell quality and egg internal quality. Egg shell quality may be measured as egg size, egg specific gravity and shell color, shell breaking strength, shell deformation (destructive or non-destructive), shell weight, percent...

Adult great spotted cuckoos, Clamator glandariusdamage the eggs of their magpie, Pica picahost without removing or eating them. The number of damaged magpie eggs was recorded in 360 parasitized nests of which 62.2% contained between one and eight damaged magpie eggs. Egg-destroying behaviour may be adaptive if it reduces nestling competition and/or enhances the hatching success of the cuckoo. T...

In this experiment, the influence of prebiotic and probiotic supplementation in the broiler breeder diets on body weight, mortality, feed intake, egg production, hatchability and humoral immunity response was investigated. A total number of 13140 female and 1260 male breeders (Cobb 500) with 26 wks of age were allocated to three treatments with six replicates (800 birds each replicate). Breeder...