Shell membrane protein system in relation to lathyrogen toxicity and copper deficiency

Abstract

A chronological account of observations on the nature of the shell membrane protein system is presented. The review indicates that although the major protein in the shell membrane is not elastin, it does contain desmosine and isodesmosinethe cross-linking amino acids. The membranes also contain small amounts of collagen. The formation of these proteins can be impaired by the inclusion of lathyrogens in the diet of laying hens. This impairment is caused by a failure to synthesize cross-links of membrane protein and this is very similar to the effect obtained when hens are fed copper-deficient diets. The disruption of the protein system has a considerable effect on the development of eggs, which are abnormal in size, shape and shell texture. The lathyrogens also have a depressing effect on egg production. The problems and prospects of utilizing seeds of certain Lathyrus plants containing lathyrogens are indicated.

Effects of low and high dietary levels of beta‐aminopropionitrile (BAPN) on the performance of laying chickens

“…Thus investigations into the causes of malformed eggs by a number of workers repeatedly proved that the problem results from faulty synthesis of membrane proteins. For further details the readers are referred to the exhaustive accounts given recently by Chowdhury (1988Chowdhury ( , 1990. The question immediately comes to mind on assessing the results on egg quality as to whether BAPN accumulates in the egg contents as a result of its dietary inclusion.…”

Effects of feeding semicarbazide to laying hens

“…Tullet (1987) reported an increase in egg weight due to inclusion of BAPN in the diet, and Baumgartner et a1 (1978) obtained similar results by feeding a diet deficient in copper. It has been stated that symptoms of copper deficiency in many ways resemble those of BAPN toxicity (Baumgartner et al 1978;Chowdhury 1990a). Chowdhury and Davis (1988) observed a slight increase in the egg weight of SC-fed birds.…”

“…The disease appears to be due to failure to synthesise cross-links of collagen (Siege1 et al 1970) and elastin (O'DeIl et al 1966) types of protein. In laying hens the shell membrane, which is made up of both collagen and elastin-like proteins, is severely disrupted due to a biochemical lesion produced as a result of lathyrogen intoxication (Leach 1982;Wong et a1 1984;Chowdhury 1990a). This disruption causes a loss of tensile strength of the membranes and makes them highly porous and weak leading to problems in the progressive deposition of eggshell during the course of egg formation (Chowdhury 1988;Chowdhury and Davis 1988).…”

“…Lathyrus seeds are cheap and important for inclusion in layer diets as protein supplements in many countries of the world where they are grown. Experiments with the toxin of Lathyrus seeds (BAPN) demonstrated clear-cut toxic effects on layer performance (Barnett et a1 1957;Chowdhury 1988Chowdhury , 1990aChowdhury and Davis 1989). Although a great deal of work has been done with BAPN using layers as experimental animals, little is known about the influence of SC on layer performance and its analogy with BAPN.…”

Effects of dietary organic or inorganic manganese, zinc, copper and chrome supplementation on the performance, egg quality and hatching characteristics of laying breeder hens

“…Zinc is a component of the carbonic anhydrase enzyme, which is crucial for supplying the carbonate ions during eggshell formation (26); manganese is the metal activator of enzymes that are involved in the synthesis of mucopolysaccharides and glycoproteins that contribute to the formation of the organic matrix of the shell (10), and copper plays the role of cofactor of the lysyl-oxydase enzyme that is important in the formation of collagen cross links present in the egg shell membrane (4). Chromium stimulates and regulates the action of insulin, which is involved in anabolic processes (22).…”