谷氨酰胺及其前体物对松浦镜鲤肌肉成分、氨基酸组成及AKP活性的影响

Effects of Gln and its precursors on muscular approximate composition,amino acid composition and AKP activities in Songpu mirror carp Cyprinus carpio Songpu

为研究谷氨酰胺及其前体物对松浦镜鲤Cyprinus carpio Songpu肌肉成分、氨基酸组成和碱性磷酸酶(AKP)活性的影响,分别用谷氨酰胺(Gln)、谷氨酸(Glu)、α-酮戊二酸(AKG)、L-鸟氨酸-α-酮戊二酸(OKG)、L-精氨酸-α-酮戊二酸(AAKG)、α-酮戊二酸钠(2Na-AKG)替代基础饲料中1.5%的葡萄糖,配制成6种等能等氮饲料,并设空白对照,共7个组,进行了8周的松浦镜鲤(初始体质量为40.27 g±3.96 g)养殖试验。结果表明:OKG组鱼体肌肉粗蛋白质含量显著高于对照组及其他处理组(P<0.05);2Na-AKG组鱼体粗灰分含量显著高于对照组及其他处理组(P<0.05);不同处理组鱼体粗脂肪含量与对照组相比均无显著性差异(P>0.05);OKG组和AAKG组鱼体肌肉水分含量显著低于对照组(P<0.05),OKG组和AAKG组鱼体肌肉苏氨酸显著高于对照组和AKG组(P<0.05),而Glu组缬氨酸含量显著高于其他处理组(除2Na-AKG组外)(P<0.05);Glu组、AKG组和2Na-AKG组肌肉必需氨基酸(EAA)总量均显著低于对照组(P<0.05);不同处理组中鱼体肌肉非必需氨基酸(NEAA)、呈味氨基酸(DAA)和总氨基酸(TAA)含量与对照组相比均无显著性差异(P>0.05);AAKG组和2Na-AKG组鱼体前肠AKP活性显著高于对照组及其他处理组(P<0.05),与对照组相比,Glu组鱼体肝脏的AKP活性显著提高(P<0.05),而血清中的AKP活性在各处理组间均未表现出显著性差异(P>0.05)。研究表明,饲料中添加1.5%的OKG能显著提高松浦镜鲤鱼体肌肉粗蛋白质及苏氨酸含量,同时能显著降低鱼体肌肉水分含量;饲料中添加1.5%的AAKG和2Na-AKG能够显著提高鱼体肠道AKP活性。

This study aimed to investigate the effects of Gin and its precursors on muscular approximate composi- tion, amino acid composition and AKP activities in Songpu mirror carp Cyprinus carpio Songpu. Seven isoprotein and isolipid diets containing glucose （ control）, glutamine （ Gin）, glusate （ Glu）, α-ketoglutarate （ AKG）, L-or- nithine-α-ketoglutarate （ OKG）, L-arginine-α-ketoglutarate （AAKG） and α-ketoglutarate sodium （2Na-AKG） were prepared. Healthy Songpu mirror carp with an average initial body weight of （40.2± 3.96 ） g were randomly assigned to thirty-five aquaria with an initial stocking density of 30 fish per aquarium and and the diets above for 56 days. The results showed the crude protein levels of fish muscle in the OKG group were significantly higher than those in the control and other treatment groups （P〈0.05）. The muscle crude ash levels in the 2Na-AKG group were significantly higher than those in the control and other treatment groups （P〈0.05）, without significant differenees in crude lipid levels of fish muscle between control and other treatment groups （P〉0.05）. The muscle crude moisture were significantly lower in OKG group and AAKG group than that in the control （P〈0.05）. Compared with the control, the Thr content of fish muscle in the OKG group and AAKG group were significantly higher （ P〈0.05 ） , while the Val content in the Glu group was significantly lower （P〈0.05）. The essential amino acid （EAA） contents of fish muscle were significantly lower in the Glu group, AKG group and 2Na-AKG group than that in the control （P〈0.05）. No significant differenees were showed in the contents of non-essential amino acid （NEAA）, delicious amino acid （DAA） and total amino acid （TAA） between control and other treatment groups （P〉0.05）. The AKP activities in the foregut of fish were significantly higher in the AAKG group and 2Na-AKG group than those in the control and other treatment groups （P〈0.05）. The AKP activities in the hepatopanereas of fish were significantly higher in the Glu group than those in the control （P〈0.05） , while no significant differenees were showed in the AKP activities in serum between control and other treatment groups （P〉0.05）. The fingings indicated that the crude protein levels and Thr contents in fish muscle significantly increased, while the moisture of fish muscle signif- icantly decreased in the fish fed the diet containing 1.5% OKG; that the AKP activities in the gut significantly in- creased in the fish fed the diets containing 1.5% AAKG and 2Na-AKG.