Effect of Dietary Glycine on Reduced Performance by Deficient and Excessive Methionine in Broilers

Transcription

1 81 Effect of Dietary Glycine on Reduced Performance by Deficient and Excessive Methionine in Broilers Yoshlyuki OHTA and Teru ISHIBASHI Animal Nutrition, Graduate School of Science and Technology, Niigata University, Niigata-shi, To clarify the alleviatory effect of dietary glycine on reduced performance caused by deficient and excessive methionine, two experiments were conducted. In Experiment 1, the adequate methionine level for the maximum performance of broilers was determined by supplementing a corn-soybean meal diet with a graded levels of methionine. In Experiment 2, the effect of glycine on the depressed performance of broilers caused by methionine deficiency and excess was studied. In experiment 1, the dietary methionine level for the maximum performance was estimated to be at 0.47%, and that for 70% of the maximum performance at 0.26 and 1.56% of diet, respectively. Therefore, in Experiment 2, the 0.26, 0.46 and 1.56% methionine diets with or without 0.60% glycine were prepared, and designated as the deficient, adequate and excess diets, respectively. Reduction of performance caused by excessive methionine was restored to 88% of the growth on the adequate diet, but that caused by methionine deficiency was not alleviated by adding glycine. Abdominal fat contents on the methionine excess diet were less than those on the deficient diet, although there were no differences in performance. Reduced abdominal fat content to 47% of the adequate diet was recovered to 67% by adding glycine. Plasma methionine concentration increased rapidly with increasing dietary methionine levels, and reduced by adding glycine. Plasma glycine, threonine and serine concentrations were not reduced in chicks fed the methionine excess diet. (Jpn. Poult. Sci., 32: 81-89,1995) Key words: Excessive methionine, Glycine supplement, Tissue weights, Plasma components, Broiler Introduction Dietary excessive methionine induces the growth depression of rats (GIRARD-GLOBA et at., 1972) and chicks (KATZ and BAKER, 1975). This growth depression is alleviated by glycine supplementation (KATZ and BAKER, 1975; UEDA and TASAKI, 1977; UEDA et al., 1979 a, b). Although, causes of methionine toxicity are not clear completely, it has been recognized that the dietary excessive methionine increases serine-threonine dehydratase activity (GIRARD-GLOBA et al., 1972; KATZ and BAKER, 1975) and results in deficiency of threonine, glycine and serine. Excessive methionine affects plasma amino acid concentrations and organ weights. When a methionine excess diet was supplied, plasma methionine concentration increased, and plasma threonine and glycine concentrations decreased in rats and chicks (LEUNG et al., 1968; UEDA and TASAKI, 1977). However, SUGIYAMA et al. (1987) reported that plasma glycine concentration was not affected by excessive methionine in rats fed a low casein diet. In kittens, plasma threonine concentration increased on Received Feb. 14, 1994

2 82 Jpn. Poult. Sci., 32 (2), 1995 a methionine excess diet (FAU et al., 1987). It is not clear that response of plasma glycine and threonine concentration to excessive methionine is specific on the low protein diet. Therefore, it is necessary to study the effect of deficient and excessive methionine on plasma biochemical components. Although, it is reported that some plasma biochemical components are affected by dietary factors (THOMAS and COMBS, 1967; WHITEHEAD and GRIFFIN, 1982), responses of plasma biochemical components to excessive methionine have not been reported. The weight of tissues are also affected by dietary methionine levels. The spleen is enlarged by dietary excessive methionine (HARTER and BAKER, 1978). The enlarged spleen is caused by the break down of blood cells due to methionine toxicity. When compared the tissue weight, it is better to use the animals with the same body weights. Therefore, in Experiment 1, the methionine level for the maximum performance was determined by supplementing with graded levels of methionine. Experimemt 2 was conducted to clarify 1) the effect of deficient and excessive methionine on growth performance and tissue weights, 2) the alleviatory effect of glycine on growth depression by deficient and excessive methionine and 3) responses of plasma amino acids and other compounds to the deficient and excessive methionine. Materials and Methods Animals In both experiments, one-day-old Cobb strain female chicks were purchased from a commercial hatchery and group-fed a commercial starter diet containing 23.0% crude protein (CP) and 3,200 kcal metabolizable energy (ME)/kg for 7 days in a temperature-(23 }3 Ž) and light-controlled (16-hlight: 4:00-20:00) room. At 8 days of age, they were allotted into 10 and 6 groups of 4 and 5 chicks with the same body weights in Experiments 1 and 2, respectively. They were housed individually in wire cages and given free access to diets and water for 10 days. At the end of the feeding period, the body weight gain and feed consumption were recorded. In Experiment 2, after recording of body weights of chicks, about 1.5ml of blood samples were taken from the wing vein for determination of plasma amino acid concentrations as reported previously (FUJIMURA et al., 1992), and 10 kinds of plasma biochemical components, i.e. triglyceride, phospholipid, total cholesterol, free fatty acids, albumin, uric acid, total protein,ƒà-lipoprotein, urea nitrogen, and glucose with a clinical chemistry analyzer (SHIMADZU, LC-7000). All chicks were killed by cutting artery after intravenous injection of 50 mg pentobarbital per chick, and 6 tissues, i.e. liver, left kidney, spleen, pancreas, adrenal and abdominal fat were weighed. Fat surrounding the gizzard and intestine extending within the ischium and surrounding the bursa was considered as abdominal fat. Diets The composition of the basal diet used in Experiments 1 and 2 is shown in Table 1. The basal diet was mainly consisted of corn and soybean meal. Crystalline L-form arginine, lysine-hci, isoleucine, threonine and tryptophan were added to meet 95% of requirements for growing broilers from 0 to 3 weeks (NRC, 1984). The diet contained

3 OHTA and ISHIBASHI: Excess Methionine and Glycine in Broilers 83 Table 1. Composition of basal diet (%) 1 Supplies per kilogram of diet: vitamin A, 15001U; vitamin D3, 200 ICU; a-tocopherol, 10mg; menadione sodium bisulfite, 0.959mg; thiamine-hno3, 1.8mg; pyridoxine-hci, 3mg; riboflavin, 3.6mg; vitamin B12, mg; biotin, 0.15mg; folic acid, 0.55mg; MnSO4, 165mg; ZnCO3, 40mg; FeSO4, 218mg; CuSO4, 20mg; Ca(IO3) 2, 0.5mg; MgCO3, 600mg; Ca-pantothenate, 10.87mg and nicotinic acid, 26.78mg. 2 Supplies to as percentage: L-Arg, 0.398; L-Lys HCI, 0.526; L-Ile, 0.049; L-Thr, 0.143; L-Trp, and L-Glu, % CP, 3,200 kcal ME/kg, 0.26% methionine and 0.24% cystine. In Experiment 1, methionine was added in the range of 0 to 1.50% at the expense of the same amounts of glutamic acid to make 10 diets with graded levels of methionine from 0.26 to 1.86%, and in Experiment 2, 0, 0.2 or 1.3% methionine with or without 0.6% of glycine was added at the expense of glutamic acid to make 0.26, 0.46 or 1.56% methionine Statistical diets. analysis Statistical significance was determined by one way ANOVA in Experiment 1, and 2 way ANOVA in Experiment 2, and Duncan's new multiple range test using the General Linear Model procedure of SAS (R) (SAS Institute, 1985). Statements of significance were based on P<0.05 unless otherwise stated. Response curve for performance (Y, body weight gain or feed efficiency) on methionine levels (X) was fitted by exponential equation as follows: Y =(A-BX) (1-e-C(X-D)) c c c(toyomizu et al., 1988); where A, B, C and D are regression coefficients to be obtained. The level of methionine for the maximum performance was estimated as a lower level at X for 95% of the maximum response. Results The body weight gain, feed intake and feed efficiency increased and then

4 84 Jpn. Poult. Sci., 32 (2), 1995 Table 2. Effect of dietary methionine level on performance of broilers from 8 to 18 days of age (Experiment 1) Values are means for 4 chicks. a-c Values within a row not having the same letter are significantly different (P<0.05). Table 3. Effect of dietary methionine levels and supplemental glycine on performance and tissue weights of broilers from 8 to 18 days of age (Experiment 2) Values are means for 5 chick. a, b Values within the same methionine level not having the same letter are significantly different (P<0.05). NS=not significant. *Significantly different from the corresponding glycine 0% group (P< 0.05). decreased with increasing dietary methionine levels as shown in Table 2. The methionine level for the maximum body weight gain and feed efficiency were estimated to be 0.43% (r2=0.98) and 0.48% (r2=0.99), respectively. The same performances, 70% of the maximum values, were achieved on the methionine deficient 0.26%

5 OHTA and ISHIBASHI: Excess Methionine and Glycine in Broilers 85 Fig.1. Plasma concentration of methionine, threonine, serine and glycine of broilers fed deficient, adequate and excess methionine diets with ( ) or without 0.6% glycine ( œ). Values are means } SE for 5 chicks and those without common letters a, b are significantly different among the same methionine level (P<0.05). *Significantly different from the corresponding glycine 0% group (P<0.05). NS=not significant. and excess 1.56% diets. The results of growing performance and tissue weights obtained in Experiment 2 are shown in Table 3. The performances of broilers on the 0.26 and 1.56% methionine diet were about 70% of that on the 0.46% methionine diet. Glycine addition to the methionine excess diet did not significantly affect the performance, but there was significant interaction between methionine ~ glycine in body weight gain and feed effeciency. When glycine was added to the methionine excess diet, the body weight gain and feed efficiency were improved, whereas such improvements were not observed on methionine deficient and adequate diets. Adversely, there was the significant effect of dietary methionine levels on ratios of kidney and pancreas to body weight. The modes of response of tissue weight and the ratio to body weight to the dietary methionine levels were not uniform. Weights of all tissues showed up-and down-responses with increasing dietary methionine levels. The ratios to body weight of abdominal fat, liver and spleen responded in the same manner, but those of kidney, pancreas and adrenal adversely showed down-and upresponse. Significant effect of glycine level was observed only in the liver and abdominal fat (P<0.05), and interaction between methionine ~ glycine was observed in the ratio of pancreas weight to body weight. When glycine was added to the methionine deficient and excess diets, the liver weight and its ratio to body weight decreased and those of

6 86 Jpn. Poult. Sc., 32 (2), 1995 Fig.2. Plasma concentration of biochemical components of broilers fed deficient, adequate and excess methionine diet with ( ) or without additional glycine ( œ). Values are means } SE for 5 chicks and those without common letters a, b among the same methionine level are significantly different (P<0.05). *significantly different from the corresponding glycine 0% group (P< 0.05). NS=not significant. abdominal fat increased. Plasma concentrations of amino acids metabolically related to methionine including methionine, threonine, glycine and serine are shown in Fig.1. Significant effects of dietary methionine levels were observed in the plasma concentration of methionine and serine. When dietary methionine increased from deficient to adequate levels, the plasma concentration of methionine remained constant and those of threonine, serine and glycine tended to decrease. When dietary methionine increased from adequate to excess levels, the plasma concentration of methionine and serine increased. Significant effects of dietary glycine levels was observed in the plasma concentration of methionine and glycine, and interaction of methionine ~glycine was observed in a plasma concentration of methionine. When glycine was added to the methionine deficient and adequate diets, the plasma concentration of methionine was not affected, but that of glycine increased. When glycine was added to the methionine excess diet, the plasma concentration of methionine decreased.

7 OHTA and ISHIBASHI: Excess Methionine and Glycine in Broilers 87 Significant effects of dietary methionine levels were observed in total protein, albumin, triglyceride and phospholipid as shown in Fig.2. When dietary methionine increased from deficient, adequate to excess levels, the plasma concentrations of triglyceride and phospholipid continued to decrease, but that of albumin decreased and then increased. Significant effects of glycine supplementation was observed only in a plasma concentration of triglyceride, and interaction of methionine ~glycine was observed in plasma concentrations of total protein. When glycine was added to the methionine excess diet, the plasma total protein concentration decreased and the plasma glucose concentration tended to decrease. Discussion From the data of performance in Experiment 1, the methionine and sulfur containing amino acid levels for the maximum performance were estimated to be 0.43 to 0.48% of the diet. The total sulfur amino acid requirements were calculated to be 0.67 to 0.72%, which were 72.0 to 77.4% of the NRC requirements for broiler chicks from 0 to 3 weeks. The low requirement in this experiment was partly due to the low dietary CP levels, 17.1% in the present study compared to 23.0% by the NRC, because the sulfur amino acid requirement increases with increasing dietary CP levels (MENDONCA and JENSEN, 1989). The growth performance decreased to 70% of the maximum values on the methionine adequate diet by feeding the 0.26 and 1.56% methionine diet. By adding glycine, the reduced growth performance by methionine deficient diet was not recovered, but that by methionine excess diet was improved to 87% of the maximum values achieved on the methionine adequate diet. The alleviatory effect of glycine on methionine toxicity has been explained by elevated cystathionine synthesis for which serine is required as a carbon skeleton source (GIRARD-GLOBA et al., 1972, KATZ and BAKER, 1975). If serine is deficient, glycine and threonine are metabolized to compensate the serine deficiency, which results in deficiency of these two amino acids. However, plasma threonine, serine and glycine concentrations did not decrease, but increased by excessive methionine in the present study. The same observation was reported in rats fed a low protein diet (SUGIYAMA et al., 1987). The partial reduction of elevated plasma methionine concentration on the methionine excess diet might reflect one of the alleviatory effects of glycine in broilers. It is reported that the abdominal fat weight and its ratio to body weight of broilers decrease with increasing dietary methionine levels (JENSEN et al., 1989). In the present study, the abdominal fat content on the methionine deficient and excess diets were lower than those on the methionine adequate diet. Although total carcass fat contents were not determined in the prersent study, there was a close relationship between the abdominal fat and carcass contents (BECKER et al., 1981). On the methionine deficient and excess diets, though the depression of growth performances were the same, the abdominal fat weight of broilers fed the methionine deficient diet decreased to 70%, and that fed the methionine excess diet to 47% of that fed the methionine

8 88 Jpn. Poult. Sci., 32 (2), 1995 adequate diet. By adding glycine, the former was restored to 84% and the latter to 61% of the value obtained on the adequate diet. These results might indicate the possibility to produce low fat broilers by supplementing with excessive methionine and glycine. The mode of response of tissues to the dietary methionine and glycine levels was not uniform. The response of liver was relatively small. HARTER and BAKER (1978) and SUGIYAMA et al., (1987) reported that excessive methionine enlarged the spleen of broilers and rats, whereas the similar tendency was not observed in the present study. Depression of plasma triglyceride and phospholipid concentrations with increasing dietary methionine levels, might be related to the decrease in abdominal fat content. However, it was unclear why total protein and albumin increase on the methionine excess diet. References BENEVENGA, N.J. (1974) Toxicity of methionine and other amino acids. Journal of Agricultural and Food Chemistry, 22: 2-9. BECKER, W.A., J. SPENCER, L.W. MIROTH and J.A. VERSTRATE (1981) Abdominal and carcass fat in five broiler strains. Poultry Science, 60: FAU, D., K.A. SMALLEY, J.G. MORRIS and Q.R. ROGERS (1987) Effect of excess dietary methionine on weight gain and plasma amino acids in kittens. Journal of Nutrition. 117: FINKELSTEIN, J.D. (1990) Methionine metabolism of mammals. Journal of Nutritional Biochemistry, 1: FUJIMURA, S., A. ANNAKA, E. WATANABE, M. TOYOMIZU and T. ISHIBASHI (1992) Rapid analysis of amino acids in plasma and feedstuffs with high performance liquid chromatograph. Bulletin of the Faculty of Agriculture Niigata University, 44: GIRARD-GLOBA, A., P. ROBIN and M. FORESTIER (1972) Long-term adaptation of weanling rats to high dietary levels of methionine and serine. Journal of Nutrition, 102: HARTER, J.M. and D.H. BAKER (1978) Factors affecting methionine toxicity and its alleviation in the chick. Journal of Nutrition, 108: JENSEN, L.S., G.L. WYATT and B.I. FANCHER (1989) Sulfur amino acid requirement of broiler chickens from 3 to 6 weeks of age. Poultry Science, 68: KATZ, R.S. and D.H. BAKER (1975) Methionine toxicity in the chick: Nutritional and metabolic implications. Journal of Nutrition, 105: LEUNG, P.M.-B., Q.R. ROGERS and A.E. HARPER (1968) Effect of amino acid imbalance on plasma and tissue free amino acids in the rat. Journal of Nutrition, 96: MENDONCA, C.X. and L.S. JENSEN (1989) Influence of protein concentration on the sulphur-containing amino acid requirement of broiler chickens, British Poultry Science, 30: National Research Council (1984) Nutrient Requirement of Poultry. 8th edition., National Academy Press, Washington, DC. SUGIYAMA, K., Y. KUSHIMA and K. MURAMATSU (1987) Effect of dietary glycine on methionine metabolism in rats fed a high-methionine diet. Journal of Nutritional Science and Vitaminology, 33: SAS Institute (1985) SAS User's Guide: Statistics., 5th editioin, Cary NC. THOMAS, O.P. and G.F. COMBS (1967) Relationship between serum protein level and body composition in the chick. Journal of Nutrition, 91: TOYOMIZU, M., K. HAYASHI, K. YAMASHITA and Y. TOMITA (1988) Response surface analyses of the effects of dietary protein feeding and growth patterns in mice from weaning to maturity, Journal of Nutrition, 118: USDA, H. and I. TASAKI (1977) Effect of excess methionine on growth, feed intake, energy utilization and plasma amino acid pattern in chicks. Japanese Poultry Science, 14:

9 OHTA and ISHIBASHI: Excess Methionine and Glycine in Broilers 89 UEDA, H., H. YOKOTA and I. TASAKI (1979 a) The effect supplemental glycine or threonine on the elevated plasma methionine concentration and the decreased feed intake of chicks fed the methionine excess diet. Japanese Poultry Science, 16: UEDA, H., H. YOKOTA and I. TASAKI (1979 b) Alleviatory effect of glycine on the methionine toxicity in chicks. Japanese Poultry Science, 16: WHITEHEAD, C.C. and H.D. GRIFFIN (1982) Plasma lipoprotein as an indicator of fatness in broilers: effect of age and diet. British Poultry Science, 23: