| 161 individuals of Rhinogobio ventralis(Savage et Dabry) were collected from Jinsha River during July to August,2008.This paper deals with the age and growth,the ratio of muscle content and nutritional composition and amino acids content of Rhinogobio ventralis(Savage et Dabry) based on the 161 speciments colleceted.The results were summarized as follows:1.The annuli on scale and otolith were observed carefully and the age of the species was diagnosed on the basis of 161 specimens.The scale is investigated using the otolith as control.Age agreement based on the scale and otolith was 96.21%.The main feature of annual-ring are fragment pattern on the scales.The fry check,false ring and spawning check can be seen occasionally.2.The analysis of composition of the catches shows that those of dominat age groups from 2 to 3 years,body-length groups from 160mm-180mm and body-weight groups from 50g-100g constitute 85.09%,56.52%and 68.32%respectively.3.The straight line relationship between the body length(L,mm) and scale radius (R,mm) can be expressed by the formula:L=25.373+56.331R(R2=0.9864,n=161), The relationship between the body length(L,mm) and body weight(W,g) can be expressed as W=1.7×10-5L3.0073(R2=0.9505,n=161).It belongs to the type of uniform growth and it can be described by the von Bertalanffy growth equation,and the parameter values are as follows:L∞=278.6966mm,W∞=383.4364g,k=0.3296,to= 0.2589.The age of growth turning point was 3.08 years;the corresponding body length and body weight were 186.02mm and 113.69g.4.The ratio of muscle content R.ventralis was 69.51%,its content of protein was 17.26%,content of fat was 11.28%,content of ash was 0.77%,content of moisture was 70.14%in nutritional composition.Total content of seventeen amino acids was 16.15% (percentage of wet weight),total content of essential amino acids was 6.31%,and the percentage of essential amino acids in total amino acids was 39.10%.Essential amino acids to no-essential amino acids were 0.6420.The constitutional rate of the essential amino acids accorded with the FAO/WHO standard basically.The content of 4 kinds delicious amino acids was 6.27%,the percentage of 4 kinds delicious amino acids in total amino acids was 38.83%.The essential amino acids index was 81.68.According to the amino acids score(AAS),the first limited amino acid was isoleucine and the second limited amino acids was valine;on the basis of chemical score(CS),the first limited amino acids was methionine+cystine and the second limited amino acids was isoleucine. A total of 10 mineral elements were determined in the flesh.Of the 10 mineral elements, the range of average contents of microelements including Ca,P,Na and Mg was 296.32μg/g-3278.14μg/g and that of microelements including Cu,Zn,Fe,Mn,Cr and Se was 0.06μg/g-112.5μg/g.Ca:P averaged 1:2.1. |
