A feeding trial was conducted for 75 d to evaluate the nutritive value of a mixture of animal by-products （MAB） as a possible protein source in diets for juvenile mangrove red snapper, Lutjanus argentimaculatus （me...A feeding trial was conducted for 75 d to evaluate the nutritive value of a mixture of animal by-products （MAB） as a possible protein source in diets for juvenile mangrove red snapper, Lutjanus argentimaculatus （mean initial body weight, 30 g）. Fish were fed one of five isonitrogenous diets （40% crude protein） replacing 0, 25% （MAB25）, 50% （MAB50）, 75% （MAB75） and 100% （MAB100） of fish meal protein with similar percentages of MAB. The MAB consisted of 25% cow liver meal, 20% leather meal, 20% meat and bone meal, 15% blood meal, 10% APC （poultry feather meal）, 8% poultry manure dried, 1.5% choline and 0.5% chromic oxide. After 75 d of feeding, fish fed with diets MAB50, MAB75 and MABI00 exhibited significantly lower growth performance than that of fish fed with control and MAB25 diets. The optimum level of MAB was estimated to be 23%. Replacement of fish meal by MAB23% showed the following performance： maximum weight gain, 510%; SGR, 2.39% and FCE, 2.83%. The MAB substitution up to 75% of fish meal protein in diets did not show differences in apparent protein digestibility （83.6% for MAB25, 79.2% for MAB50, 78.7% for MAB75） compared with control （83.4%）, whereas in MABI00 group digestibility （65.3%） was significantly lower than in other groups. The apparent phosphorus absorption of test diet groups was significantly higher （37.1% for MAB25, 28.5% for MABS0, 55.6% for MAB75 and 54.5% for MABI00） than that of control （1 1.2%）. The levels of protein and ash in the whole body, carcass and viscera increased as MAB substitution in diets increased, whereas lipids and moisture remained consistent among all treatment groups. These results showed that approximately 23% of fish meal protein could be replaced by a mixture of animal by-products for juvenile snapper growing from 30 g to 167 g in 75 d without compromising growth performance and feed efficiency.展开更多
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
文摘A feeding trial was conducted for 75 d to evaluate the nutritive value of a mixture of animal by-products （MAB） as a possible protein source in diets for juvenile mangrove red snapper, Lutjanus argentimaculatus （mean initial body weight, 30 g）. Fish were fed one of five isonitrogenous diets （40% crude protein） replacing 0, 25% （MAB25）, 50% （MAB50）, 75% （MAB75） and 100% （MAB100） of fish meal protein with similar percentages of MAB. The MAB consisted of 25% cow liver meal, 20% leather meal, 20% meat and bone meal, 15% blood meal, 10% APC （poultry feather meal）, 8% poultry manure dried, 1.5% choline and 0.5% chromic oxide. After 75 d of feeding, fish fed with diets MAB50, MAB75 and MABI00 exhibited significantly lower growth performance than that of fish fed with control and MAB25 diets. The optimum level of MAB was estimated to be 23%. Replacement of fish meal by MAB23% showed the following performance： maximum weight gain, 510%; SGR, 2.39% and FCE, 2.83%. The MAB substitution up to 75% of fish meal protein in diets did not show differences in apparent protein digestibility （83.6% for MAB25, 79.2% for MAB50, 78.7% for MAB75） compared with control （83.4%）, whereas in MABI00 group digestibility （65.3%） was significantly lower than in other groups. The apparent phosphorus absorption of test diet groups was significantly higher （37.1% for MAB25, 28.5% for MABS0, 55.6% for MAB75 and 54.5% for MABI00） than that of control （1 1.2%）. The levels of protein and ash in the whole body, carcass and viscera increased as MAB substitution in diets increased, whereas lipids and moisture remained consistent among all treatment groups. These results showed that approximately 23% of fish meal protein could be replaced by a mixture of animal by-products for juvenile snapper growing from 30 g to 167 g in 75 d without compromising growth performance and feed efficiency.
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.
