3个大珠母贝养殖群体生物学特征及肌肉营养成分分析

Biological characteristics and muscle nutrition components analysis of three cultured populations of Pinctada maxima

【目的】探究不同大珠母贝(Pinctada maxima)养殖群体外部形态特征和肌肉营养成分的差异,为不同地理大珠母贝种质资源的分类管理与合理利用提供科学依据,也为野生大珠母贝种质资源的管理与保护提供理论参考。【方法】采集广西北海、海南三亚和广东徐闻等地的大珠母贝养殖群体,测量其体质量、壳长、壳宽、壳高及铰合线长,检测大珠母贝肌肉营养成分,并根据联合国粮农组织和世界卫生组织(FAO/WHO)建议的氨基酸评分标准模式进行品质评价。【结果】北海(BH)群体的壳长、壳宽、壳高和铰合线长均高于三亚(SY)群体和徐闻(XW)群体;SY群体除了体质量和壳宽外,其他形态性状均显著低于BH群体和XW群体(P<0.05,下同)。除了BH群体与XW群体间的壳宽性状差异系数(1.50)大于1.28外,其余性状差异系数均小于1.28,说明3个大珠母贝养殖群体间的形态差异尚未达到亚种分化水平。主成分分析和层级聚类分析结果均显示,3个群体的散布并未完全分离,彼此间均有一定程度的重合。XW群体肌肉鲜样的粗蛋白含量显著高于BH群体和SY群体,但粗脂肪含量差异不显著(P>0.05)。3个群体共检出17种氨基酸,且均以天冬氨酸(Asp)、谷氨酸(Glu)、甘氨酸(Gly)和精氨酸(Arg)含量较高,合计占总氨基酸的41.15%~45.56%;SY群体的必需氨基酸指数(EAAI)为73.23%,高于BH群体(64.48%)和XW群体(45.53%)。3个群体共检出9种脂肪酸,SY群体多检测出α-亚麻酸,而BH群体和XW群体多检测出油酸。在3个群体肌肉中未检出n-6系列多不饱和脂肪酸(n-6 PUFA),所检出的n-3系列多不饱和脂肪酸(n-3 PUFA)也只有3种[二十碳五烯酸(EPA)、二十二碳六烯酸(DHA)和α-亚麻酸],且以SY群体的含量最高(0.0443%)。【结论】大珠母贝氨基酸含量丰富且均匀,属于优质蛋白,具有较高的营养价值,且SY群体的综合营养价值优于BH群体和XW群体。

【Objective】This study aimed to investigate the differences in external morphological characteristics and muscle nutrition components among different cultured populations of Pinctada maxima,providing a scientific basis for the classification,management and rational utilization of germplasm resources of P.Maxima from different geographical origins,and a theoretical reference for the management and protection of germplasm resources of wild P.maxima.【Method】Cultured populations of P.maxima were collected from Beihai of Guangxi,Sanya of Hainan,and Xuwen of Guangdong.Their body weight,shell length,shell width,shell height and hinge length were measured.The nutrition components of muscle were detected,and the quality was evaluated according to the amino acid scoring model recommended by the Food and Agriculture Organization of the United Nations and the World Health Organization(FAO/WHO).【Result】The shell length,shell width,shell height and hinge length of Beihai(BH)population were all higher than those of Sanya(SY)population and Xuwen(XW)population.Except for body weight and shell width,other morphological traits of SY population were significantly lower than those of BH population and XW population(P<0.05,the same below).The difference coefficient for all traits were less than 1.28,except for the shell width between the BH and XW populations(1.50),indicating that the morphological differences among the three cultured populations of P.maxima did not reach the subspecies differentiation level.Both principal component analysis and hierarchical cluster analysis showed that the distribution of the three populations was not completely separated and they overlapped with each other to some extent.The crude protein content of fresh muscle samples in XW population was significantly higher than that in BH and SY populations,but there was no significant difference in crude fat content(P>0.05).A total of 17 amino acids were detected in the three populations,with the contents of aspartic acid(Asp),glutamic acid(Glu),glycine(Gly)and arginine(Arg)being the most abundant,accounting for 41.15%-45.56%of the total amino acids.The essential amino acid index(EAAI)of SY population was 73.23%,higher than that of BH population(64.48%)and XW population(45.53%).A total of nine fatty acids were detected in the three populations,withα-linolenic acid being more abundant in the SY population,and oleic acid being more abundant in the BH and XW populations.No n-6 polyunsaturated fatty acids(n-6 PUFA)were detected in the muscles of the three populations,and only three kinds of n-3 polyunsaturated fatty acids(n-3 PUFA)were detected[eicosapentaenoic acid(EPA),docosahexaenoic acid(DHA)andα-linolenic acid],with the highest content in SY population(0.0443%).【Conclusion】P.maxima is rich in amino acids and has a balanced amino acid profile,making it a high-quality protein with high nutritional value.The comprehensive nutritional value of SY population is better than that of BH population and XW population.