Cathepsin B, D and H activities in muscles of chicks of fast and slow growing strains: Effect of age and diet

Saunderson, C. Linda; S, Leslie

doi:10.1016/0300-9629(89)90568-9

Cited by 11 publications

(3 citation statements)

References 24 publications

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“…The proportion of body-weight that was breast or leg muscle in the chicks given the five different diets was fairly similar except for the breast and leg muscle of chicks given diet C and leg muscle of chicks given diet CM. Breast muscle has previously been shown (Bryan, 1985;Saunderson & Leslie, 1989) to be more sensitive than other tissues to lower protein (amino acid) supply. The slower growth of breast and leg muscle in these chicks may also reflect a less mature stage of development of the birds.…”

Section: Discussionmentioning

confidence: 99%

Changes in body-weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks

Saunderson

Mackinlay

1990

Br J Nutr

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The experiments described here were set up (a) to investigate the effect of age and (b) to investigate the effect of giving five diets which varied in methionine and choline or betaine contents on some of the enzymes that metabolize these nutrients in chick liver. Growth and carcass composition of the chicks fed on the different diets were also examined. There was no obvious relationship between age and enzyme activity in young chicks. Only a diet low in methionine (but not one low in choline) showed a significant decrease in growth and a change in carcass composition. The effects of diet on enzyme activity were complex. Choline oxidase (EC 1.1.3.17) activity was affected by the level of choline in the diet, being high when choline was present at high levels, especially when methionine was limiting. 5-Methyltetrahydrofolate homocysteine methyltransferase (EC 2.1.1.3) had a high activity in the livers of chicks fed on a conventional diet compared with those given semi-purified diets. Other enzymes showed minor changes in response to the diet. The diet low in methionine showed a lower activity of cystathionine psynthase (EC 4.2.1.22) and slightly higher activities of methionine adenosyltransferase (EC 2 -5.1 .6) and betainehomocysteine methyltransferase (EC 2.1.1.5; compared with other diets), suggesting that this diet encouraged re-methylation of homocysteine at the expense of trans-sulphnration to cystathionine. The findings obtained in these studies form a useful basis for further investigation of the metabolic interrelationships between methionine and related nutrients. The essential amino acid methionine fulfils a number of important functions in metabolism. Apart from being a constituent of proteins, it has a unique role as the initiating amino acid of all polypeptide synthesis, it donates methyl groups in a number of important synthetic reactions, it is a precursor of the polyamines spermine and spermidine and its sulphur moiety can be used in the synthesis of cysteine.The methylation role of methionine is fundamental to a number of areas of intermediary metabolism, e.g. amino acid metabolism, phospholipid synthesis, DNA and RNA synthesis and function, and is involved in numerous other pathways such as C, metabolism and creatine synthesis. Consequently methionine is known to interact with a number of other essential nutrients, the most obvious of these being cysteine (and sulphate), choline, vitamin B,, and folic acid. Interactions also exist with other amino acids such as arginine, glycine, serine and threonine (Keshavarz & Fuller, 1971 ;Girard-Globa et al. 1972).In order to investigate the nutritional interactions, information about the metabolism of the nutrients involved is required. The first step towards this is to measure how the activities of the enzymes involved change as the levels of the nutrients in the diet change. In the studies reported here, chicks were given one of five different diets varying in methionine or choline (or betaine) content for a period of 14 d. Growth, food intake and carcas...

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Section: Discussionmentioning

confidence: 99%

Changes in body-weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks

Saunderson

Mackinlay

1990

Br J Nutr

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“…1978;Tomas el a/. 1984;Saunderson & Leslie, 1989). Presumably muscle protein degradation is increased to supply deficient amino acids, increasing NtMH output.…”

Section: The Efect Of Level Of Dietary Protein On M M H Excretionmentioning

confidence: 99%

“…broilers (Guillaume, 1976). In growing birds, diets with low protein or amino acid contents increase the total and fractional rates of muscle protein degradation (Maruyama et al 1978;Saunderson & Leslie, 1989). It is not known whether the same would be true at maturity given that bodyweight was stable.…”

mentioning

confidence: 99%

Muscle protein degradation assessed by N^t-methylhistidine excretion in mature White Leghorn, dwarf broiler and normal broiler males maintained on either low- or high-protein diets

Hocking

Saunderson

1992

Br J Nutr

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Protein degradation rates were assessed by the excretion of Nt-methylhistidine (NtMH) in four strains of mature chickens, two White Leghorns and two broilers (dwarf and normal), fed on diets containing two levels of dietary protein. Over 0.9 of labelled NtMH was recovered within 7 d of injection from three White Leghorn, three dwarf and three normal broiler males. Protein degradation, measured by NtMH output, was related to adult body-weight by the power 0.71 and strain intercepts were significantly different. Strain differences disappeared when the rate of output of NtMH per unit lean was evaluated. The rate of output of NtMH per unit muscle was higher in birds fed on a low-protein diet of 100 g crude protein (nitrogen x 6.25; CP)/kg compared with males fed on 150 g CP/kg. It was concluded that the lower rate of protein degradation in broiler compared with layer strains at young ages is related to increased adult body-weight in agreement with well-established biological principles.

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Enzymes in the meat industry

Etherington¹,

Bardsley²

1995

Enzymes in Food Processing

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Cathepsin B, D and H activities in muscles of chicks of fast and slow growing strains: Effect of age and diet

Cited by 11 publications

References 24 publications

Changes in body-weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks

Changes in body-weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks

Muscle protein degradation assessed by N^t-methylhistidine excretion in mature White Leghorn, dwarf broiler and normal broiler males maintained on either low- or high-protein diets

Enzymes in the meat industry

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Cathepsin B, D and H activities in muscles of chicks of fast and slow growing strains: Effect of age and diet

Cited by 11 publications

References 24 publications

Changes in body-weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks

Changes in body-weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks

Muscle protein degradation assessed by Nt-methylhistidine excretion in mature White Leghorn, dwarf broiler and normal broiler males maintained on either low- or high-protein diets

Enzymes in the meat industry

Contact Info

Product

Resources

About

Muscle protein degradation assessed by N^t-methylhistidine excretion in mature White Leghorn, dwarf broiler and normal broiler males maintained on either low- or high-protein diets