title: Effects of dietary protein content and 2-hydroxy-4-methylthiobutanoic acid or DL-methionine supplementation on performance and oxidative status of broiler chickens.
abstract: Besides its typical role as an amino acid in protein synthesis, methionine is an important intermediate in methylation reactions. In addition, it can also be converted to cysteine and hence plays a role in the defence against oxidative stress. The present study was conducted to investigate further the role of DL-methionine (DLM) and its hydroxy analogue, DL-2-hydroxy-4-methylthiobutanoic acid (DL-HMTBA), on zootechnical performance and oxidative status of broiler chickens. Male broiler chickens were reared on two diets differing in crude protein (CP) content (low-protein, 18·3 % v. high-protein, 23·2 % CP) and were supplemented either with 0·25 % DLM or 0·25 % DL-HMTBA. Reducing the dietary protein content resulted in an impaired body weight gain (P < 0·0001). However, supplementation of DL-HMTBA to the low-protein diet partially alleviated these negative effects (P = 0·0003). This latter phenomenon could be explained by the fact that chickens fed DL-HMTBA-supplemented diets displayed a better antioxidant status as reflected in lower lipid peroxidation probably as a consequence of their higher hepatic concentrations of total and reduced glutathione compared with their DLM counterparts. On the other hand, within the high protein levels, uric acid might be an important antioxidant to explain the lower lipid peroxidation of high-protein DL-HMTBA-supplemented chickens. Hepatic methionine sulfoxide reductase-A gene expression was not significantly affected by the dietary treatments. In conclusion, the present study indicates that there are interactions between dietary protein content and supplementation of methionine analogues with respect to broiler performance and antioxidant status, also suggesting a causal link between these traits.
authors: Laboratory of Livestock Physiology, Immunology and Genetics, Department of Biosystems, K.U. Leuven, Kasteelpark Arenberg 30, 3001, Leuven, Belgium.
authors: Quirine
authors: Q
authors: Swennen
authors: Pierre-André
authors: PA
authors: Geraert
authors: Yves
authors: Y
authors: Mercier
authors: Nadia
authors: N
authors: Everaert
authors: Anneleen
authors: A
authors: Stinckens
authors: Hilke
authors: H
authors: Willemsen
authors: Yue
authors: Y
authors: Li
authors: Eddy
authors: E
authors: Decuypere
authors: Johan
authors: J
authors: Buyse
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D002645:Chickens / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood; D017931:DNA Primers / Q000235:genetics; D004044:Dietary Proteins / Q000008:administration & dosage*; D019587:Dietary Supplements; D004435:Eating; D015870:Gene Expression; D015227:Lipid Peroxidation; D008099:Liver / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D051150:Methionine Sulfoxide Reductases / Q000235:genetics; D009929:Organ Size; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D014284:Triiodothyronine / Q000097:blood; D015430:Weight Gain
chemical_list: D000975:Antioxidants; D017931:DNA Primers; D004044:Dietary Proteins; D014284:Triiodothyronine; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D008715:Methionine; D051150:Methionine Sulfoxide Reductases; D003345:Corticosterone