Studies On Growth?digestion?immune And M Uscle Nutrient Of Tilapia Nilotica In Shanmei R Eservior

The characteristics of growth,digestion,immune and the nutritional composition in muscle of Tilapia niotica were studied,based on samples collected from Shanmei reservior in four seasons.It aimed to investigate the effect of seasonal variation on fish physiological and biochemical charactersistics,which could provide scientific basis for the healthy breeding of fish.The research had four main parts as following:1.The research on the growth and feeding composition of Tilapia niloticaThe weight mainly ranged from 220.0 g to 420.0g and body length ranged from 17 cm to 24cm of Tilapia nilotica.Most of them were 1 age,accounting for 43.75%.The relationship between body weight and length was W=0.1889L^2.4713?r=0.934?.The relationship of body length and scale size was L=10.132+23.095R?r=0.928?.The Von Bertalanffy equation were L_t?cm?=32.9×[1-e^{-0.209?t+1.31?}],W_t?g?=720.4×[1-e^{-0.209?t+1.31?}]^2.4713,whose growth inflection point was 3.01 ages.Research showed that hepatosomatic index of Tilapia nilotica was significantly impacted by seasonal changes.Viscerasomatic index and fatness were mainly affected by the mating season.Tilapia nilotica mainly feeded on Bacillariophyta and Chlorophyta,then were Cyanobacteria and Euglena.In December,zonnplankers accounted for a certain number like rotifer.Tilapia nilotica was omnivorous animal.2.The research on digestive enzymes of Tilapia niloticaThe protease and amylase were most active in the digestive of the liver,intestines and stomach,and the activity of protease was showed:summer>winter>sprin g>autumn?P<0.05?,while the amylase activity showed as:summer>autumn>spring>winter?P<0.05?.The lipase activity was similar in liver and intestine,and the lipase activity of stomach was far below than that of hepatopancreas and intestine.Protease and amylase activity in different digestive organs were significantly different?P<0.05?,which was intestines>liver>stomach.3.The immune related enzymesof Tilapia niloticaImmune related enzymes of Tilapia nilotica were significantly influenced by seasonal variation,in which SOD,CAT and POD enzyme activity had the same tendency in four seasons whose enzyme activity was the highest in summer,and the lowest in winter.The activity of GSH-Px,GR and GST in winter were significantly higher than that of spring and summer?P<0.05?.The T-AOC activity was the highest in winter and lowest in autumn.ACP and AKP activity in winter were significantly higher than that of spring and summer and autumn?P<0.05?.MDA concentration in winter was significantly higher than that of spring and summer and autumn?P<0.05?,and the differences between the spring,summer and autumn was not significant?P>0.05?.The NO concentration was significant difference in four seasons?P<0.05?,whose was the highest in winter and lowest in summer.4.The research on muscle nutrient of Tilapia niloticaThere was no significant difference of moisture?fresh weight?in four seasons?P>0.05?.The crude protein and ash?fresh weight?in spring were significantly lower than that of summer,autumn and winter?P<0.05?.The crude fat?fresh weight?was the highest in autumn,and the lowest in spring.In four seasons,the content of glutamic acids in muscle were:16.33%,15.93%,16.33%and 16.47%,respectively,which was the highest among the 17 amino acids.The content of cystine was the lowest whose content were 0.74%,0.88%,0.85%and 0.93%in four seasons,respectively.In four seasons the ratio of essential amino acids/total amino acid were 40.2%,40.8%,40.7%and 40.6%respectively;the ratio of essential amino acids/non-essential amino acid were 78.7%,81.0%,80.4%and 80.2%respectively;the ratio of a flavor amino acids/total amino acids were 39.1%,38.3%,38.5%and 38.5%respectively.The fatty acids of muscle had higher level of palmitic acid and oleic acid.