3 – oxycarotenoids in poultry feeds

Summary

.After a brief discussion of the essential chemical properties of carotenoids, the identification, occurrence and distribution of the pigments in the gonads and related organs of plants and animals have been reviewed. The information available concerning the metabolism of carotenoids in reproductive tissues and their possible function in reproduction has also been reviewed systematically.



In the higher plants, as maturation proceeds the carotenoid content of the tissues decreases, owing probably to the redirection of carotenoid synthesis into the reproductive organs. Further, the synthetic mechanism itself must be altered in some way because new carotenoids, never encountered in leaves, are produced in the reproductive organs. There is no evidence that carotenoids are involved in fertilization. In fact, many pollens contain no carotenoids.



Differential distribution of carotenoids in male and female gametes is encountered in some species of both algae and fungi, but whereas nothing is known about carotenoid metabolism and function in relation to reproduction in fungi, it is claimed that appropriate mixtures of stable and labile crocetin dimethyl esters stimulate both male and female gametogenesis in the alga Chlamydomonas.



In aquatic animals carotenoids are actively mobilized into the gonads during sexual reproductive activity, and in some cases are rendered water-soluble by attachment to proteins. Carotenoids do not appear to be necessary for normal embryonic development, but one report indicates their possible importance as fertilization hormones. Carotenoids may be present in the gonads to ensure that the larvae are adequately equipped for chromatophore responses. Changes in general coloration associated with sexual activity are also often mediated through carotenoids; in the case of the fish Cyclopterus lumpus, for example, astaxanthin appears in the skin in large amounts during the summer spawning period. Similar changes can be observed in some insects, for instance, the bright yellow colour of sexually mature locusts is due to accumulation of β-carotene in the cuticle.



In mammals which store carotenoids, these pigments undergo metabolic changes associated with parturition, but as not all mammals store carotenoids, and since many similar changes occur with vitamin A, it is doubtful whether the carotenoids are of significance per se.



Although carotenoids appear to be unnecessary for the normal development of birds in both the pre- and post-embryonic stages, they are actively mobilized into birds' eggs. They may, however, be necessary for optimum conditions of fertilization by increasing the sperm competitive ability of cocks, i.e. when hens are inseminated with an equal mixture of spermatozoa from cocks on an adequate diet and those on a lutein-deficient diet, a larger proportion of offspring are produced from the normal group than from the lutein-deficient group.

Carotenoids and reproduction

A review on development of novel strategies for controlling Salmonella Enteritidis colonization in laying hens: Fiber-based molt diets

The Oxidized Flavor in Milk and Dairy Products: A Review

Publisher Summary This chapter assembles and relates the results of the investigations that have been reported in the technical literature, and collates the results of those researches into the nature of the chemical, physical, and biological changes which result in quality differences and deterioration before and during processing and storage. Some of the quantitatively minor constituents of eggs, such as pigments and vitamins, contribute notably to consumer acceptance and to the nutritive value of powders and are, therefore, of interest in connection with quality deterioration. Because of the marked variations in contents of these constituents, with conditions of egg production, their relations to the general problem has been discussed. The chapter discussed the composition and properties of the egg lipids that are significant factors in quality retention of the dried products. Because of the changes in colors of whole egg powders during storage, pigmentation of the raw materials used for drying is of considerable interest in relation to the subject of this chapter. The technical literature reveals reports of a number of studies concerning the nature of changes taking place in shell and frozen eggs which may be expected to influence the properties of powders prepared from them. Palatability tests are used by several purchasing agencies as a means of assessing the quality of products. Disadvantages to the general use of the method have been mentioned and because of the disadvantages, efforts have been made to devise objective methods of evaluation that would show close correlation with palatability measurement. The chapter discusses several methods of evaluation that would show close correlation with palatability measurement.

Victor Heiman

Papers

The Transmission of Xanthophylls in Feeds to the Yolk of the Hen’s Egg

The Relative Flavin (Vitamin G) Content of Dried Skimmilk, Dried Whey, and Dried Buttermilk

A Curative Method for the Assay of Vitamin D with Chicks

The Effect on Yolk Color of Various Ingredients in Poultry Feeds