The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets wer...The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets were formulated to contain 0% (A0), 10% (A10), 20% (A>sub>20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM), as partial fish meal (FM) substitutes. Diet A0 without AM served as a control. Fish growth decreased as AM level exceeded 20% in diets (P 0.05). Crude lipid was significantly lower in fish fed A50 and significant differences were also found in crude ash (P 20, A30 and A50. High level of the fern reduces growth without negatively affecting fatty acid in fish. Fish PUFA, especially the (n - 3) fatty acids, are affected positively, even when fed 50% AM, which is good for the quality of the fish produced in regard to the benefits for the health of consumers.展开更多
Interbreeding of Clarias gariepinus and Heterobranchus bidorsalis was done to produce F1 with fast growing trait using synthetic ovaprim hormone （0.5 ml/kg）. Mean hatching rates were very high （between 72.5% and 92...Interbreeding of Clarias gariepinus and Heterobranchus bidorsalis was done to produce F1 with fast growing trait using synthetic ovaprim hormone （0.5 ml/kg）. Mean hatching rates were very high （between 72.5% and 92.5%）. The parental stock of C. gariepinus showed higher survival value of 96.0% under indoor rearing. The hybrid produced by crossing of ♂H. bidorsalis and ♀C. gariepinus showed higher growth rate in hapa under suspended （14. 1 0 g） and non-suspended condition （14.30 g） in earthen pond at the end of four months rearing. The growth rate under suspended and non-suspended condition were very high and were not significant different from each other. Comparatively, the hybrid of the cross between （♀） H. bidorsalis and （♂） C. gariepinus was better than the other cross under non-suspended condition while the parental strain ofH. bidorsalis was to produce under the suspended condition. The purpose of this is to produce improved fish with fast growing trait and other qualitative characters that could meet the economic target of Nigerian aquaculture, The hybrids have potential as commercial food fish.展开更多
Dried shrimp is a popular aquatic food worldwide due to its unique flavor.However,its flavor qualities on the market remain uneven.This study aimed to compare flavor substances in dried shrimp processed by Litopenaeus...Dried shrimp is a popular aquatic food worldwide due to its unique flavor.However,its flavor qualities on the market remain uneven.This study aimed to compare flavor substances in dried shrimp processed by Litopenaeus vannamei from two aquaculture patterns(earthen pond and greenhouse)using amino acid automatic analyzer,high-performance liquid chromatography(HPLC),gas chromatography(GC)-ion mobility spectrometry(IMS),and GC-mass spectrometry(GC-MS).The results revealed that dried shrimp from earthen pond had significantly higher free amino acids and 5’-nucleotides than those from greenhouse(P<0.05),and their corresponding equivalent umami concentrations(EUCs)were 23.45 g MSG(100 g)^(−1)and 14.86 g MSG(100 g)^(−1),respectively.For volatile compounds,GC-IMS analysis indicated significant differences in volatile compounds between dried shrimp from different aquaculture patterns.According to the quantitative analysis of GC-MS,11 volatile compounds were identified as aroma-active compounds(AACs),of which six AACs(1-octen-3-ol,3-methylbutanal,nonanal,trimethylamine,2,5-dimethylpyrazine,and 2,3,5-trimethylpyrazine)were found in all dried shrimp samples.Although dried shrimp from greenhouse possesses higher OAVs,OAVs of(E,E)-2,4-nonadienal(fishy smell),and 3,5-diethyl-2-methylpyrazine(burnt smell)reached 171.2 and 333 respectively,imparting negative effects on flavor.In general,dried shrimp from earthen pond had a better flavor profile than those from greenhouse.展开更多
文摘The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets were formulated to contain 0% (A0), 10% (A10), 20% (A>sub>20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM), as partial fish meal (FM) substitutes. Diet A0 without AM served as a control. Fish growth decreased as AM level exceeded 20% in diets (P 0.05). Crude lipid was significantly lower in fish fed A50 and significant differences were also found in crude ash (P 20, A30 and A50. High level of the fern reduces growth without negatively affecting fatty acid in fish. Fish PUFA, especially the (n - 3) fatty acids, are affected positively, even when fed 50% AM, which is good for the quality of the fish produced in regard to the benefits for the health of consumers.
文摘Interbreeding of Clarias gariepinus and Heterobranchus bidorsalis was done to produce F1 with fast growing trait using synthetic ovaprim hormone （0.5 ml/kg）. Mean hatching rates were very high （between 72.5% and 92.5%）. The parental stock of C. gariepinus showed higher survival value of 96.0% under indoor rearing. The hybrid produced by crossing of ♂H. bidorsalis and ♀C. gariepinus showed higher growth rate in hapa under suspended （14. 1 0 g） and non-suspended condition （14.30 g） in earthen pond at the end of four months rearing. The growth rate under suspended and non-suspended condition were very high and were not significant different from each other. Comparatively, the hybrid of the cross between （♀） H. bidorsalis and （♂） C. gariepinus was better than the other cross under non-suspended condition while the parental strain ofH. bidorsalis was to produce under the suspended condition. The purpose of this is to produce improved fish with fast growing trait and other qualitative characters that could meet the economic target of Nigerian aquaculture, The hybrids have potential as commercial food fish.
基金supported by the National Key R&D Program of China (No.2018YFD0901004)the Central Public-Interest Scientific Institution Basal Research Fund,YSFRI,CAFS (No.20603022020013).
文摘Dried shrimp is a popular aquatic food worldwide due to its unique flavor.However,its flavor qualities on the market remain uneven.This study aimed to compare flavor substances in dried shrimp processed by Litopenaeus vannamei from two aquaculture patterns(earthen pond and greenhouse)using amino acid automatic analyzer,high-performance liquid chromatography(HPLC),gas chromatography(GC)-ion mobility spectrometry(IMS),and GC-mass spectrometry(GC-MS).The results revealed that dried shrimp from earthen pond had significantly higher free amino acids and 5’-nucleotides than those from greenhouse(P<0.05),and their corresponding equivalent umami concentrations(EUCs)were 23.45 g MSG(100 g)^(−1)and 14.86 g MSG(100 g)^(−1),respectively.For volatile compounds,GC-IMS analysis indicated significant differences in volatile compounds between dried shrimp from different aquaculture patterns.According to the quantitative analysis of GC-MS,11 volatile compounds were identified as aroma-active compounds(AACs),of which six AACs(1-octen-3-ol,3-methylbutanal,nonanal,trimethylamine,2,5-dimethylpyrazine,and 2,3,5-trimethylpyrazine)were found in all dried shrimp samples.Although dried shrimp from greenhouse possesses higher OAVs,OAVs of(E,E)-2,4-nonadienal(fishy smell),and 3,5-diethyl-2-methylpyrazine(burnt smell)reached 171.2 and 333 respectively,imparting negative effects on flavor.In general,dried shrimp from earthen pond had a better flavor profile than those from greenhouse.
