Changes in growth, the activities of major digestive enzymes and intestinal tissues during the early development of Procypris mera
This study employed enzymatic methods, tissue sectioning techniques, and routine measurements to explore the pattern of change in the activities of lipase, amylase, trypsin, alkaline phosphatase and their growth and intestinal tissue changes during the growth of Procypris mera from 1 DAH(Day after hatching) larvae to 80 DAH juveniles.Meanwhile, this study also established a suitable feeding strategy for the larvae and juven-ile P.mera.The results showed that the fitted growth equations for the total length and body weight of P.mera during the development of larvae and juveniles were y=-0.00481x2+1.00636x+3.33020(R2=0.985, P<0.05) and y=0.1731x2+3.76634x-40.61142(R2=0.990, P<0.05),and the specific growth rate was 7.7402 mg/d.The intestinal tissue first showed a large number of cup-shaped cells and mucosal folds at 8 DAH, then the layering of the intestinal tissue was obvious at 15 DAH, followed by variable heights of mucosal folds and thickening of the muscle layer at 27 DAH, and finally, the appearance of intestinal glands at 45 DAH, revea-ling the perfecting of development.The activities of lipase, amylase, trypsin, and alkaline phosphatase were detected at 1 DAH in P.mera, and these four digestive enzymes showed different trends.Lipase activity in-creased and then decreased from 1 to 13 DAH and reached a minimum(0.654±0.165) U/g at 13 DAH, and increased to the peak of(1.437±0.110) U/g at 17 DAH, and decreased gradually and then increase sharp-ly.Amylase activity reached a minimum(0.039±0.002) U/g at 3 DAH, and then increased significantly, fol-lowed by a significant increase and a fluctuating downward trend after reaching a maximum(0.146±0.005) U/g at 7 DAH.Trypsin activity reached a minimum(232.677±26.620) U/mg protein at 6 DAH, increased sig-nificantly from 6 to 13 DAH, and showed an overall upward trend after 17 DAH.Alkaline phosphatase activity increased slowly from 1 to 4 DAH, increased significantly from 5 to 13 DAH, fluctuated and decreased from 13 to 35 DAH, and then increased dramatically after 35 DAH.It can be concluded that the activities of the main digestive enzymes during the early development of P.mera change significantly with growth, and its diges-tive function is gradually perfected.P.mera should be fed a bait containing sufficient protein and lipid from 5 to 15 DAH, a compound feed that provides adequate protein and lipid is recommended from 15 to 45 DAH, and a nutritionally balanced compound feed containing a certain proportion of carbohydrates is recommended from 45 to 80 DAH.According to the change in digestive enzyme activities and their growth and intestinal tissue in the early development stage of P.mera, the feeding strategy and food formula were optimized to lay a founda-tion for improving the survival rate of seed cultivation.
万方数据
维普
