Comparative Analysis of Nutritional Components in Muscles between Wild and Cultured Masu Salmon Oncorhynchus masou

In this paper,approximate nutritional components and amino acid content were determined in muscles of female wild population(WP)with body weight of 2500-3000 g and female cultured population(CP)with body weight of 750-1250 g masu salmon Oncorhynchus masou in the gonadal development stage IV by conventional method.The results showed that there were significantly higher crude protein and significantly lower crude fat in fresh muscle of WP than that in CP(P<0.05),but not significant differences in the contents of moisture and crude ash between WP and CP(P>0.05).Eighteen kinds of amino acids were detected in muscles of WP and CP,with higher total content of amino acids(TAA),essential amino acids(EAA)and four kinds of delicious amino acids(DAA)in WP than those in CP(P<0.05).The amino acid score(AAS)and chemical score(CS)revealed that the first limiting amino acid was tryptophan in two populations,with essential amino acid index(EAAI)of 75.59%in WP and 70.77%in CP.The findings indicated that the amino acid contents in muscles of CP are lower than that of WP,but the amino acid nutritional value evaluation indicators of both populations are very close,and both have high nutritional value.

Gluconeogenesis during starvation and refeeding phase is affected by previous dietary carbohydrates levels and a glucose stimuli during early life in Siberian sturgeon(Acipenser baerii)

Gluconeogenesis responses was assessed during a short starvation period and subsequent refeeding in Siberian sturgeon(Acipenser baerii) previously fed different dietary carbohydrates levels and experienced to a glucose stimuli during early life. The sturgeon larvae were previously fed either a high glucose diet(G) or a low glucose diet(F) from the first feeding to yolk absorption(8 to 12 d post-hatching [dph]). Each group of fish was sub-divided into 2 treatments at 13 dph and was fed either a high-carbohydrate diet(H) or a low carbohydrate diet(L) until 20 wk. In the current study, the fish in 4 groups(GL, FL, GH and FH) were experienced to starvation for 21 d following by re-feeding of their corresponding diets for 21 d.Fish were sampled at postprandial 6 and 24 h before starvation(P6 h and P24 h), starvation 7,14 and 21 d(S7, S14 and S21) and 1, 7,14 and 21 d during refeeding(R1, R7, R14 and R21). Plasma samples during refeeding were taken at P6 h at each time point. Glycaemia levels, liver and muscle glycogen contents,activities and mRNA levels of hepatic gluconeogenic enzymes were examined. We found that both dietary carbohydrate levels and early glucose stimuli significantly affected the metabolic responses to starvation and refeeding in Siberian sturgeon(P < 0.05). During prolonged starvation, Siberian sturgeon firstly mobilized the liver glycogen and then improved gluconeogenesis when the dietary carbohydrates were abundant, whereas preserved the liver glycogen stores at a stable level and more effectively promoted gluconeogenesis when the dietary carbohydrates are absent to maintain glucose homoeostasis.During refeeding, as most teleostean, Siberian sturgeon failed controlling the activities and mRNA levels of phosphoenolpyruvate carboxykinase cytosolic forms(PEPCK-C), fructose-1,6-bisphosphatase(FBPase),but particularly controlled phosphoenolpyruvate carboxykinase mitochondrial forms(PEPCK-M) activities and mRNA expression of glucose-6-phosphatase(G6 Pase, except in GL group). Siberian sturgeon has a full compensatory ability on growth, but this ability would be obstructed by early glucose stimuli when refeeding the low carbohydrate diet after S21.