Nutrient requirements of poultry

The gizzard has a number of important functions, such as aiding digestion by particle size reduction, chemical degradation of nutrients and regulation of feed flow, and responds rapidly to changes in the coarseness of the diet. This review summarises findings on the function of the gizzard, the interaction between diet and gizzard function, and the nutritional consequences of these interactions. Due to the reported improvements in nutrient availability when structural components which stimulate gizzard development has been added to the diet, it may be recommended to include at least 20 to 30% cereal particles larger than 1 mm in size, or to include at least 3% coarse fibres such as oat hulls, in the diet.

The gizzard: function, influence of diet structure and effects on nutrient availability

Evaluation of Protein Solubility as an Indicator of Underprocessing of Soybean Meal

The most salient feature of the class Aves is the ubiquity of feathers. These structures play vital roles in thermoregulation, protection, communication, and locomotion in birds (Stettenheim 1976). The maintenance of the integrity of its feather coat, or plumage, is essential to a bird’s survival. The periodic replacement of all or parts of the plumage is known as molt. Molt undoubtedly requires a wide array of adjustments in the physiology, energetics, and nutrition of birds. What is known about these adjustments is the focus of this chapter. Different groups of birds have evolved different schemes for molting. Variation in patterns and timing of molt among groups of birds have been reviewed by others (Stresemann and Stresemann 1966; Palmer 1972; Payne 1972; King 1974; Boere 1976; Hahn et al. 1992) and are discussed here only briefly.

Energetics and Nutrition of Molt

A radiochemical method was developed to estimate cholyltaurine hydrolase potentials and rates of cholyltaurine hydrolysis in chicken intestinal homogenates This method was used to monitor the effects of antibiotic feed additives on cholyltaurine hydrolase activity Avoparcin, bacitracin methylenedisalisylic acid, efrotomycin, lincomycin, penicillin G procaine, and virginiamycin improved rate of weight gain and feed conversion of chicks and decreased cholyltaurine hydrolase activity in ileal homogenates relative to those of nonmedicated control birds The results provided the first evidence that feeding selected antibiotics at subtherapeutic levels can affect bile acid-transforming enzymes in small-intestinal homogenates The inverse relationship between growth performance and cholyltaurine hydrolase activity raises the possibility that specific inhibitors of this enzyme may promote weight gain and feed conversion in livestock and thereby reduce or eliminate the need for antibiotic feed additives

Subtherapeutic levels of antibiotics in poultry feeds and their effects on weight gain, feed efficiency, and bacterial cholyltaurine hydrolase activity.

S. L. Balloun

Papers

Influence of Dietary Fat and Choline on Serum and Egg Yolk Cholesterol in the Laying Chicken

Leucine, Isoleucine and Valine Interactions in Turkey Poults

Dietary phosphorus needs of laying hens.

Effect of Processing Methods on Utilization of Feather Meal by Broiler Chicks

Evaluation of the Effect of Breed on Vitamin B6 Requirements of Chicks