The Compensation Growth After Starvation And Physiology Mechanism In Juvenile Siberian Sturgeon(Acipenser Baerii)

This study is about the compensatory growth of Siberian sturgeon (average initialbody weight19.48±0.1g) under17.5±1℃after starvation and refeeding for differentdays. The changes of growth index, the index of blood, body composition and thedigestion enzyme activity have been studied in Siberian sturgeon. Countermeasure andmechanism of compensatory growth have been discussed. The result is as follows:After starvation, the body weight, length, hepatosomalic index, corldition factorand specific growth rate in the experimental group decrease. The body weight,hepatosomalic index, corldition factor and specific growth rate are sensitive tostarvation while the body length is not sensitive to starvation. After refeeding, the bodycharacter is no significant difference except for body weight compared with controlgroup. In the period of refeeding, the growth speed of starvation group all exceeds thecontrol group. The change of food conversion efficiency is very obvious.After starvation, red blood cell count and hemoglobin of Siberian sturgeon levelsdecline significantly while white blood cell count shows a downward trend; afterrefeeding, the physiological index of the blood returned to the level with no significantdifference compared with control group. After starvation, the glucose level of blooddeclines significantly and it declines faster in the early period of starvation, As thestarving time increases it maintains a certain level. Total cholesterol and triglyceridelevels are decreased. And the total protein content of the blood did not changesignificantly. After refeeding, the biochemical index of the blood returned to the levelwith no significant difference compared with control group.After starvation, the content of muscle glycogen and liver glycogen descendswhile the content of moisture and ash of Siberian sturgeon ascends. After refeeding, the body component is no significant difference except for muscle glycogen comparedwith control group. The results indicate that the liver is the main organ stores energy ofSiberian sturgeon; when hungry the fish uses the glycogen first and then uses the fat.After starvation, the activities of protease, tryptase and of digestive tract inSiberian sturgeon all decrease. And they all fall faster in the early period then later fallslower. Amylase activity decreased after the first of increased while lipase activity firstdecreased and then increased. After refeeding, the activities of amylase and lipase areon the rise compared to before. The activities of protease and tryptase returned to thelevel with no significant difference compared with control group. The distributionorderliness of different digestive enzymes activities in the digestive tract is: amylaseactivity is highest in intestines, secondly in stomach, thirdly in hepatopancreas.Protease and tryptase activities are highest in stomach, secondly in intestines, thirdly inhepatopancreas. Lipase activity is highest in intestines, secondly in stomach, thirdly inhepatopancreas.It could be seen from the change of body weight and specific growth rate thatSiberian sturgeon shows completely compensatory growth. It could be seen from thechange of food conversion efficiency and feeding rate that the completelycompensation growth is mainly due to increased food conversion efficiency. Starvationshould be avoided or reduced in breeding process of Siberian sturgeon. It has importantsignificance to feeding Siberian sturgeon by scientific using of this physiologicalphenomenon.