Apparent and true metabolizable energy values of feedstuffs for ducks.

Two experiments were conducted, each with 24 White Pekin ducks, to determine the AME and TME content of five feedstuffs for ducks. In each experiment, fasting losses were obtained from six ducks and six ducks were used for each feedstuff. Each experiment lasted 102 h with an initial 48-h period and a 54-h excreta collection period. During the first 48-h period, all birds were tube-fed dextrose (30 g/100 mL of water) at 8 and 32 h after feed was withdrawn. Thirty grams of each feedstuff were tube-fed (30 g/100 mL of water) at 48 and 54 h after feed was withdrawn. The birds from which fasting losses were obtained were intubated with 30 g dextrose (30 g/100 mL of water) at 48 and 54 h after feed was withdrawn. Excreta were collected during the last 54 h into bags screwed onto lids sutured around the vent of each bird. In the first experiment, the feedstuffs evaluated were corn, dehulled oats, and wheat. The fasting energy and nitrogen losses per bird in the 54-h collection period were 12.1 kcal and 0.29 g, respectively. The AMEn values for the birds fed corn, dehulled oats, and wheat were 3.10, 3.48, and 3.14 kcal/g, respectively. The TMEn values for the respective feedstuffs were 3.27, 3.64, and 3.30 kcal/g. In the second experiment, the feedstuffs evaluated were corn, parboiled rice, and rye. The fasting energy and nitrogen losses per bird in the 54-h collection period were 18.9 kcal and 1.09 g, respectively. The AMEn values for the birds fed corn, parboiled rice, and rye were 3.24, 3.45, and 2.69 kcal/g, respectively. The TMEn values for the respective feedstuffs were 3.40, 3.61, and 2.85 kcal/g. The data provide new information on AMEn and TMEn values of corn, wheat, parboiled rice, dehulled oats, and rye for ducks.

A simple model for predicting the response of chicks to dietary enzyme supplementation.

Two experiments with Leghorn chicks and data from five publications were analyzed to determine whether a simple general equation could be used to predict the relationship between the amount of a crude enzyme added to a diet and chick performance. The maximum improvements in weight gain and feed: gain ratio in Leghorn chicks fed rye diets containing different concentrations of enzymes were as high as 61 and 42%, respectively. Regression analyses demonstrated that there was usually a high linear correlation (r2 > 0.9, P < 0.05) between the concentration of the enzyme when transformed into its logarithmic value and weight gain or the feed:gain ratio. The general prediction equation was Y = A + B(logX), where Y is the performance value (i.e., weight gain, grams), A is the intercept (y-axis), B is the slope of the line (change in performance per units of enzyme in the diet), and X is the amount of enzyme in the diet. The slope of the line provides an index of the overall efficacy of the enzyme treatment. The log-linear model shows that for every ninefold increase in amount of enzyme in the diet (i.e., when the amount was increased to 10 times the starting amount), there was only a doubling of improvement in chick performance. High correlations (r2 values) were also obtained when data from the literature were analyzed. The equation was applicable to different classes and ages of poultry fed diets containing rye, wheat, barley, and lupins. These studies demonstrate that there is a linear relationship between the amount of enzyme added to the diet, when expressed as a logarithmic value, and the corresponding performance of chickens.

[Substantiation of the concept of "freshness" with fodder rye and wheat as examples]. / Untersuchungen zur Objektivierung des Begriffes "Frischezustand" am Beispiel geschädigten Futterroggens und Futterweizens

In moderately or severely damaged fodder rye and wheat, the catalase test and the acidity determination are suited for corroborating the results of the organoleptic examination; But it must be emphasized that organoleptic tests cannot be replaced by the determination of chemical parameters. The present studies indicate that the substantiation of freshness by means of chemical parameters is limited in case of light or moderate deterioration.