J. W. Deaton

Effect of dietary fibre on the performance of laying hens

1. In tests to determine whether gizzard weight could be influenced by dietary fibre concentrations, caged layers were fed on diets containing 15, 30 or 60 g pine shavings/kg diet. 2. As dietary fibre content increased, gizzard weight increased, but there was no effect on body weight, hen‐day production, egg weight, efficiency of food conversion, mortality, percentage of liver ether extract or egg shell breaking strength. Percentage of body ether extract tended to be lower when pine shavings were fed.

High‐fibre sunflower meal as a replacement for soyabean meal in layer diets

1. Dietary fibre content of a layer diet was increased by substituting a high‐fibre sunflower meal for soyabean meal. 2. Gizzard weight and intestine length were significantly increased by increased dietary fibre. 3. Efficiency of food conversion decreased but egg production, egg weight, shell breaking strength and mortality were not affected by dietary sunflower meal.

Physiological changes associated with acclimation of broiler chickens to constant temperatures

An experiment was conducted to determine whether the physiological parameters that respond to temperature would equate to a common level after birds are acclimated to differing temperatures and then reared as one group at a common temperature. Results show that of the parameters measured, the heart/body weight ratio is the most sensitive to temperature changes. When birds were reared in differing constant temperatures from 1 to 28 days of age and then subjected to a common environment, by 56 days of age, the heart/body weight ratio had equated. However, the liver- and adrenal/body weight ratio and hematocrit did not completely equate for the temperature extremes by 56 days of age. Parameters measured but unaffected by temperature treatment were spleen- and bursa/body weight ratios.