Time-temperature indicators(TTIs) are convenient intuitive devices that are widely used to predict food quality. The aim of this study is to develop a new simple device which can be attached to food packages as a qual...Time-temperature indicators(TTIs) are convenient intuitive devices that are widely used to predict food quality. The aim of this study is to develop a new simple device which can be attached to food packages as a quality indicator for turbot sashimi. In this study, a solid TTI based on the reaction between tyrosinase and tyrosine was developed. The Arrhenius behavior of this enzymatic TTI was studied. The kinetics of the tyrosinase-based TTI was investigated in the form of color change from colorless to dark black induced by the enzymatic reaction. The mathematical formula for the color alterations as a function of time and temperature was established. The longest indication time for the developed TTI was 50 hours at 4℃. The activation energy of the tyrosinase-based TTI was 0.409 k J mol^(-1). The suitability of the tyrosinase-based TTI was validated for turbot sashimi using total plate count. The feasibility of using this TTI as a quality indicator for turbot sashimi was assessed based on the activation energy and indication time. Therefore, the tyrosinasebased TTI system developed in this study could be used as an effective tool for monitoring the quality changes of turbot sashimi during the distribution and storage.展开更多
An 8-week feeding experiment was performed to evaluate the effect of dietary genistein on growth performance,body composition,and digestive enzymes activity of juvenile Nile tilapia(Oreochromis niloticus).Four isonitr...An 8-week feeding experiment was performed to evaluate the effect of dietary genistein on growth performance,body composition,and digestive enzymes activity of juvenile Nile tilapia(Oreochromis niloticus).Four isonitrogenous and isoenergetic diets were formulated containing four graded supplements of genistein:0,30,300,and 3 000 μg/g.Each diet was randomly assigned in triplicate to tanks stocked with 15 juvenile tilapia(10.47±1.24 g).The results show that 30 and 300 μg/gdietary genistein had no significant effect on growth performance of Nile tilapia,but the higher level of genistein(3 000 μg/g)significantly depressed the final body weight and specific growth rate.There was no significant difference in survival rate,feed intake,feed efficiency ratio or whole body composition among all dietary treatments.An assay of digestive enzymes showed that the diet containing 3 000 μg/ggenistein decreased stomach and hepatopancreas protease activity,and amylase activity in the liver and intestine,while a dietary level of300 μg/g genistein depressed stomach protease and intestine amylase activities.However,no significant difference in stomach amylase activity was found among dietary treatments.Overall,the results of the present study indicate that a high level of dietary genistein(3 000 μg/g,or above) would significantly reduce the growth of Nile tilapia,partly because of its inhibitory effect on the activity of major digestive enzymes.Accordingly,the detrimental effects of genistein,as found in soybean products,should not be ignored when applied as an alternative ingredient source in aquaculture.展开更多
Growth is a polygenic trait that is under the influence of multiple physiological pathways regulating energy metabolism and muscle growth.Among the possible growth-regulating pathways in vertebrates,components of the ...Growth is a polygenic trait that is under the influence of multiple physiological pathways regulating energy metabolism and muscle growth.Among the possible growth-regulating pathways in vertebrates,components of the somatotropic axis are thought to have the greatest influence.There is growing body of literature focusing on the somatotropic axis and its role regulating growth in fish.This includes research into growth hormone,upstream hypothalamic hormones,insulin-like growth factors,and downstream signaling molecules.Many of these signals have both somatic effects stimulating the growth of tissues and metabolic effects that play a role in nutrient metabolism.Signals of other endocrine axes exhibit profound effects on the function of the somatotropic axis in vivo.In this review we highlight recent advances in our understanding of the teleost fish endocrine somatotropic axis,including emerging research using genetic modified models.These studies have revealed new aspects and challenges associated with regulation of the important steps of somatic growth.展开更多
基金the Science and Technology Major Projects of Shandong Province (No. 2015ZDZX05 003)the National Science & Technology Pillar Program (No. 2015BAD16B0902)
文摘Time-temperature indicators(TTIs) are convenient intuitive devices that are widely used to predict food quality. The aim of this study is to develop a new simple device which can be attached to food packages as a quality indicator for turbot sashimi. In this study, a solid TTI based on the reaction between tyrosinase and tyrosine was developed. The Arrhenius behavior of this enzymatic TTI was studied. The kinetics of the tyrosinase-based TTI was investigated in the form of color change from colorless to dark black induced by the enzymatic reaction. The mathematical formula for the color alterations as a function of time and temperature was established. The longest indication time for the developed TTI was 50 hours at 4℃. The activation energy of the tyrosinase-based TTI was 0.409 k J mol^(-1). The suitability of the tyrosinase-based TTI was validated for turbot sashimi using total plate count. The feasibility of using this TTI as a quality indicator for turbot sashimi was assessed based on the activation energy and indication time. Therefore, the tyrosinasebased TTI system developed in this study could be used as an effective tool for monitoring the quality changes of turbot sashimi during the distribution and storage.
基金Supported by the National Natural Science Foundation of China(No.31170322)
文摘An 8-week feeding experiment was performed to evaluate the effect of dietary genistein on growth performance,body composition,and digestive enzymes activity of juvenile Nile tilapia(Oreochromis niloticus).Four isonitrogenous and isoenergetic diets were formulated containing four graded supplements of genistein:0,30,300,and 3 000 μg/g.Each diet was randomly assigned in triplicate to tanks stocked with 15 juvenile tilapia(10.47±1.24 g).The results show that 30 and 300 μg/gdietary genistein had no significant effect on growth performance of Nile tilapia,but the higher level of genistein(3 000 μg/g)significantly depressed the final body weight and specific growth rate.There was no significant difference in survival rate,feed intake,feed efficiency ratio or whole body composition among all dietary treatments.An assay of digestive enzymes showed that the diet containing 3 000 μg/ggenistein decreased stomach and hepatopancreas protease activity,and amylase activity in the liver and intestine,while a dietary level of300 μg/g genistein depressed stomach protease and intestine amylase activities.However,no significant difference in stomach amylase activity was found among dietary treatments.Overall,the results of the present study indicate that a high level of dietary genistein(3 000 μg/g,or above) would significantly reduce the growth of Nile tilapia,partly because of its inhibitory effect on the activity of major digestive enzymes.Accordingly,the detrimental effects of genistein,as found in soybean products,should not be ignored when applied as an alternative ingredient source in aquaculture.
基金supported by the National Basic Research Program of China(2010CB126302 and 2014CB138602)to Yin Zhan
文摘Growth is a polygenic trait that is under the influence of multiple physiological pathways regulating energy metabolism and muscle growth.Among the possible growth-regulating pathways in vertebrates,components of the somatotropic axis are thought to have the greatest influence.There is growing body of literature focusing on the somatotropic axis and its role regulating growth in fish.This includes research into growth hormone,upstream hypothalamic hormones,insulin-like growth factors,and downstream signaling molecules.Many of these signals have both somatic effects stimulating the growth of tissues and metabolic effects that play a role in nutrient metabolism.Signals of other endocrine axes exhibit profound effects on the function of the somatotropic axis in vivo.In this review we highlight recent advances in our understanding of the teleost fish endocrine somatotropic axis,including emerging research using genetic modified models.These studies have revealed new aspects and challenges associated with regulation of the important steps of somatic growth.
