The Growth Rule Of Polydon Spathula And Study On Effects Of Starvation On Fatty Acid Changes And Its Size

This study summarized the growth regularity of Paddlefish in different development stages, the fatty acid composition changes and the bodily form changes during starvation, this could provide the reference data for Paddlefish seedling cultivation, nutrition status of Paddlefish fry, and the management during the winter; the results of the study were as follows:(1)The experiment 1 studied the 3, 5, 7, 13, 19, 25 days after hatching of growth characteristics of Paddlefish larval and juvenile, the results indicated that before feeding the growth equation between total length and hatching time was y=0.1288x+0.7134, R2=0.9993,after feeding the growth equation between total length and feeding time was y=0.9133e0.0785 x,R2=0.9913, both the two stages as a whole, the growth equation between total length and hatching time was y=0.8948e0.0796 x, R2=0.9950; before feeding the growth equation between weight and hatching time was y=0.0035x-0.0032, R2=0.9932, after feeding the growth equation between weight and feeding time was y=0.0061e0.1893 x, R2=0.9948, both the two stages as a whole the growth equation between weight and hatching time was y=0.0049e0.2004 x,R2=0.9911; both the two stages as a whole the relationship equation between weight and total length was W=0.007L2.513. These results indicated: before feeding length and weight of Paddlefish larvae grown linearly with hatching time, after feeding length and weight of Paddlefish larvae and juvenile grown exponentially with hatching time after feeding, before and after feeding as a whole total length and weight of Paddlefish larvae and juvenile grown exponentially with hatching time, the relationship between weight and total length was power function.(2)After 186 d of the pond aquaculture experiment, the results showed that the average weight 10.74 g of Paddlefish, with 186 d breeding can reach 384.49 g/tail, weight increased 35.80 times. The growth equation between total length and time was y=-0.0012x2+0.4129x+17.635, R2=0.99; the growth equation between weight and time was y=2.9317x+0.6167, R2=0.9912, the growth equation between weight and total length was W=0.04L2.957, R2=0.998. These results indicated: under this experimental condition, the young Paddlefish average length and a quadratic polynomial time relationship, a linear correlation weight time, its growth in the test environment conditions were growth uniformity.(3)The experiment 2 studied the 3, 5, 7, 13, 19, 25 days after hatching of Paddlefish larval and juvenile fatty acid composition changes, the results indicated that prophase-larvae,SFA significantly increased with hatching time(P<0.05); MUFA significantly decreased with hatching time(P<0.05); PUFA does not change significantly with hatching time(P>0.05);C18:2 n-6、C18:3 n-3、n-6 PUFA significantly decreased(P<0.05), EPA、DHA、n-3 PUFA significantly increased(P<0.05); After Paddlefish larvae and juvenile fed biological bait, SFA increased first and then decreased with hatching time(P<0.05), MUFA first decreased and then increased and decreased then again(P<0.05), PUFA first increased and then decreased and increased then again with hatching time(P < 0.05), C18:2 n-6 first increased and then decreased(P<0.05), C18:3 n-3 first increased and then decreased and increased again(P<0.05), EPA、DHA first decreased and then increased(P<0.05). These results indicated: before feeding, Paddlefish larvae for different fatty acids in the body use the order was MUFA>n-6PUFA > n-3 PUFA and SFA; After Paddlefish larvae and juvenile fed biological bait, the effect of biological bait fatty acid composition on the fatty acid composition of Paddlefish larvae and juvenile increasing significantly, this might cause the fatty acid composition of Paddlefish larvae and juvenile differences with development time.(4)the results of feeding rhythm and gastrointestinal emptying time showed that: the highest feeding peak was 17:00, the secondly highest feeding peak was 5:00, the lowest feeding peak was 23:00, stomach evacuated after starvation for six hours, however intestinal did not evacuated after starvation for thirty-six hours; in addition the experiment studied the fatty acid composition changes in 0-72 hours during starvation by fasting test. The results indicated that after 0-72 hours of starvation, the ratio of SFA and MUFA significantly decreased with the prolonging of starvation(P<0.05), the ratio of PUFA increased with the prolonging of starvation(P<0.05), EPA ratio had a increasing trend(P<0.05), DHA ratio also had a increasing trend but had no significant difference(P>0.05). These results indicated:Paddlefish juveniles had feeding rhythm feeding in the morning and night; during starving period Paddlefish juvenile mainly consumed SFA and MUFA to supply energy, while PUFA was seldom utilized for energy, and Paddlefish juvenile had a strong ability to reserve EPA and DHA.(5)The experiment 3 collected 300 healthy Paddlefish(average weight479.21±42.36g), the body length, total length, body height, body wide thick, kiss long, kiss wide were determined respectively before and after winter, changes were observed before and after winter, and studied its rule by means of statistical means. The results showed that after winter the weight of Paddlefish was significantly lower than before the winter(P<0.05); after winter reduced by 9.7%, body length, total length, body height, kiss long and kiss wide wereno significant differences(P>0.05), body thickness after winter was significantly lower than before the winter(P<0.05). Body length and body height ratio was no significant difference after winter(P > 0.05), body length and body thickness ratio increased significantly after winter(P<0.05), At the same time after winter condition factor was significantly lower than before the winter. The 3D graph showed before winter the concentration was higher than after winter, but there was no obvious mobility was reversed, after weight standardized 3D graph became more dispersed, before winter concentration was still higher than after winter. These results indicated: Paddlefish body thickness after winter was significantly lower than before the winter, the body length and body fat thickness ratio increased significantly, condition factor significantly reduced and 3D graph dispersion changes were mainly caused by the weight loss after the winter.