Egg production in poultry

BOX 15.1 Nutrient effects on embryonic gene expression, embryo survival and subsequent performance 

In contrast to layers, pullets being reared as broiler breeders (i.e. meat-type birds) have to be restricted in food intake, otherwise they grow too fast and their subsequent egg production is much reduced. The recommended restriction to 40 per cent of appetite (i.e. their intake if unrestricted) leaves them hungry and often difficult to manage. 

Productive flocks of layers produce an average of about 350 eggs per bird per year thus, on an average day 350/365 = 95 per cent of birds will lay an egg. Egg production would not be expected to go below 75 per cent in a commercial flock. Then-eggs weigh on average 60 g for white strains and 62 g for brown strains, have the 

A hen weighing 2.0 kg has a fasting metabolism of about 0.36 MJ/kg per day, or 0.60 MJ/day, and utUises metabolisable energy for maintenance and production with a combined efficiency of about 0.8. Its requirement for metabolisable energy 

the term 60 W estimates the maintenance requirement for available lysine. Similar equations are available for the other indispensable amino acids for which the requirements of layers have been quantified in addition to lysine, these include methionine (often the first-limiting amino acid for layers), tryptophan and isoleucine. Glycine (or its substitute, serine) is apparently non-essential for layers. 

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Symptoms of deficiency in animals include poor appetite, stunted growth, and weight loss increased incidence of irritabihty and convulsions (tetany) some growth abnormahties decreased egg production in poultry with reduced hatchabihty and thin eggsheU quahty and birth of weak, dead, or deformed offspring in other animals. 

The most obvious impact of mycotoxins is the inability to sell crops for human or animal food due to contamination with even relatively low levels of certain mycotoxins. In certain developing countries where there is less regulation or monitoring of human and animal exposure to toxins, there are risks of higher human health costs and animal death. Additional losses can be from a number of unseen problems such as reduction in birth rate in certain animals, decline in milk production by dairy cattle and egg production in poultry, loss of... 

Nutrient requirements for reproduction are considered in Chapter 15, which also includes nutritional influences on puberty, fertility and fecundity and the requirements for egg production in poultry and growth of the foetus. 

Egg production in poultry imposes large requirements for nutrients, especially amino acids and calcium, and these have been quantified in the form of detailed feeding standards. 

Renema R.A., Robinson F.E., Feddes J.J., Fasenko G.M. and Zuidhoft M.J. (2001). Effects of light intensity from photostimulation in four strains of commercial egg layers 2. Egg production parameters , Poultry Science, 80, 1121-1131. 

Decker, E.A. and Cantor, A.H. (1992) Fatty acids in poultry and egg products, in Fatty Acids in Foods and Their Health Implications, ed. C.K. Chow, Marcel Dekker, New... 

Davis, G.S. and Anderson, K.E. (2002) The effects of feeding the direct-fed microbial, primalac, on growth parameters and egg production in single comb white leghorn hens. Poultry Sci 81, 755-759. 

Although indoor systems of egg production are much cheaper to run than outdoor organic systems, due to higher egg production per hen per year and to lower feed costs, poultry longevity can be increased outdoors, which will lower the cost of replacement birds. Thompson (1978) tested his future breeding stock in an outdoor environment which had carried hens continuously for many years, with a consequent build-up of disease. Those pullets which survived became the foundation stock. 

As has been pointed out earlier in this chapter, the dietary consumption and historical medicinal use of carotenoids has been well documented. In the modern age, in addition to crocin, 3.7, and norbixin, 3.8, several carotenoids have become extremely important commercially. These include, in particular, astaxanthin, 3.6 (fish, swine, and poultry feed, and recently human nutritional supplements) lutein, 3.4, and zeaxanthin, 3.3 (animal feed and poultry egg production, human nutritional supplements) and lycopene, 3.2 (human nutritional supplements). The inherent lipophilicity of these compounds has limited their potential applications as hydrophilic additives without significant formulation efforts in the diet, the lipid content of the meal increases the absorption of these nutrients, however, parenteral administration to potentially effective therapeutic levels requires separate formulation that is sometimes ineffective or toxic (Lockwood et al. 2003). 

Bush, P.B., J.T. Kiker, R.K. Page, N.H. Booth, and O.J. Fletcher. 1977. Effects of graded levels of toxaphene on poultry residue accumulation, egg production, shell quality and hatchability in white leghorns. Jour. Agric. Food Chem. 25 928-932. 

Food Safety and Inspection Service (FSIS) sets standards for food safety and inspects meat, poultry, and egg products produced domestically and imported. The Service inspects animals and birds at slaughter and processed products at various stages of the production process, and analyzes products for microbiological and chemical adulterants. FSIS also informs the public about meat, poultry, and egg product food safety issues. FSIS works with the Research, Education and Economics mission area on food safety research issues and the Animal and Plant Health Inspection Service on instances where animal diseases impact food safety. FSIS also facilitates the management of US activities pertaining to the Codex Alimentarius Commission, an international organization created by the United Nations, to promote the health and economic interests of consumers while encouraging fair international trade in food. 

Qin, X. and H. Klandorf. 1991. Effect of dietary boron supplementation on egg production, shell quality, and calcium metabolism in aged breeder hens. Poultry Sci. 70 2131-2138. 

It may thus be concluded that l-(chloromethyl)- and 1-ethoxysilatrane are worth using in poultry farming in order to increase the productivity of hens and the quality of eggs and meat. 

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