This study was conducted to determine the effect of hen production cycle (HPC) and the effect of egg weight (EW) at the same egg production level on egg quality, egg composition, hatchability, duckling quality, and first-week BW in Pekin ducks. For HPC, hatching eggs were obtained from different Pekin-duck breeder flocks, aged 31 wk for the first production cycle (HPC1) and 78 wk for the second...

Understanding the genetic basis of phenotypic variation is essential for predicting the direction and rate of phenotypic evolution. We estimated heritabilities and genetic correlations of morphological (fork length, pectoral and pelvic fin ray counts, and gill arch raker counts) and life-history (egg number and individual egg weight) traits of pink salmon (Oncorhynchus gorbuscha) from Likes Cre...

Straková E., P. Suchý, M. Šugerková, M. Macháček: Positive Effect of Plant-Based Diet on the Performance and Health of Laying Hens. acta vet. Brno 2007, 76: S31-S37. an entirely plant-based feed mixture was prepared to minimize the potential risk of transmitting prion infections through animal feed. It consisted of two protein components (soya extracted meal and lupin seed meal) and was compare...

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,...

Accurately identifying resistance to gastrointestinal nematode infections requires the ability to identify animals with low and high intensities of infection. The pathogenic effects of nematodes depend upon both the length and number of worms, neither of which can be measured in live animals. Indices that predict these quantities are urgently needed. Monthly fecal egg counts, bodyweights, IgA c...

Few studies have examined how avian life-history traits vary within populations as elevation increases and climate becomes more severe. We compared egg and clutch sizes of Mountain Bluebirds (Sialia currucoides) nesting at two elevations (1500 m and 2500 m above sea level) in the Bighorn Mountains of Wyoming over two years. Eggs laid by females at the high-elevation site were, on average, signi...

abbasali gheisari*, peyman ghayor department of animal science, isfahan research center for agriculture and natural resources, isfahan,iran   * corresponding author e-mail: [email protected]     received: 15 august 2013 accepted: 21 november 2013       abstract   this experiment was conducted to investigate the effect of feeding 5 experimental diets containing 0, 5, 10, 15 and 20% rapesee...

Blue-green and brown-spotted eggshells in birds have been proposed as sexual signals of female physiological condition and egg quality, reflecting maternal investment in the egg. Testing this hypothesis requires linking eggshell coloration to egg content, which is lacking for brown protoporphyrin-based pigmentation. As protoporphyrins can induce oxidative stress, and a large amount in eggshells...