NUTRITION OF OYSTERS: GLYCOGEN FORMATION AND STORAGE. 



157 



The optimum concentration of dextrose for glycogen formation was found to be 

 about 0.25 per cent. It was found that i per cent of dextrose was toxic. Oysters exposed 

 to it showed inability to close their shells normally after 24 hours' exposure and rapidly 

 died off in about two or three days. If removed from the sugar-containing water soon 

 after signs of distress appeared, the oysters recovered their normal behavior in the course 

 of a few days' immersion in running sea water. Some experiments contrasting the gly- 

 cogen formation in 0.25 per cent dextrose with that in o.i per cent dextrose are given 

 in Table 4. 



Table 4. — The Effect of DrPFERENT Concentrations of Dextrose on Glycogen Formation. 



Experi- 

 ment 

 No. 



Concen- 

 tration of 

 dextrose. 



Treatment of oysters (is used for each analysis). 



Ash in 

 dried 



meats. 



Glycogen 

 in dried 

 meats. 



Glycogen 

 in ash- 

 free 

 solids. 



Control analysis to be compared with Nos. 37 and 38 



In sea water, sp. gr. 1.015. with o.i per cent dextrose, 36 hours, aerated. 

 Same as No. 37, but continued for 72 hours 



Control analysis to be compared with Nos. 43 and 44 



In sea water, sp. gr. 1.02a, with 0.1 per cent dextrose, 24 hours, aerated 

 Same as No. 43, but with 0.25 per cent dextrose 



Same as Nos. 43 and 44, but without dextrose 



Per cent. 

 35- so 

 30.72 

 38.6s 



31.92 

 32-95 

 31. SO 



Per cent. 



5-48 

 6-34 

 7-44 



7-79 

 9.90 

 12.70 



8.98 



Per cent. 



8.49 

 9. IS 

 10.45 



11.50 

 14.76 

 18.33 



13-38 



By comparison of experiments Nos. 37 and 38 with 6, 11, and 12 (shown in Table 2), 

 evidence of more rapid formation of glycogen in 0.25 per cent dextrose than in 0.1 

 per cent is seen in addition to the data shown in Table 4. 



The effect of different specific gravities of the sea water containing dextrose on 

 glycogen formation was studied. Fresh or nearly fresh water did not permit glycogen 

 formation. The evidence points to the fact that any change in the salt concentration 

 at the time oysters are transferred from ordinary sea water to dextrose-containing 

 water is a deterrent to maximum glycogen formation. Experiments bearing on this 

 point are reported in Table 5. 



Table $■ — The Effect op Varying Specific Gravity of the Sea Water on Glycogen Formation. 



Experi- 

 ment 

 No. 



Specific 

 gravity 

 of the 

 water. 



1.023 

 I. coo 

 1. 010 

 1. 016 

 1.023 

 1.023 

 1.023 



1.023 

 1. 000 

 1. 000 



1.023' 



1.023 

 1-006 

 1.006 



1.023 



l.OIO 



1.023 



Treatment of oysters (is used for each analysis). 



Control analysis to be compared with Nos. 40 to 45 



In aerated fresh water containing o-i per cent dextrose, 24 hours 



la aerated water (M fresh. 'A sea water) with o-i per cent dextrose, 24 hours. 

 In aerated water (K fresh, K sea water) with 0.1 per cent dextrose, 34 hours. 



In aerated sea water with o-i per cent dextrose. 24 hours 



In aerated sea water with 0.35 per cent dextrose, 24 hours 



Same as Nos. 43 and 44, but without dextrose, control 



Control analysis to be compared with Nos. 47 to 49 



In aerated fresh water with 0-25 per cent dextrose, 24 hours 



Same as No. 47, but continued 72 hours, water changed daily 



Control analysis, same lot as Nos. 46 1048, in sea water tmtil end of experiment 

 No. 48 



Control analysis to be compared with Nos- 51 and 52 



In aerated water (K sea water. K fresh) with 0.1 per cent dextrose, 36 hours. 

 Same as No. 51, but continued 73 hours 



Control analysis to be compared with Nos. S4 and 55 



In aerated water (M fresh. 14 sea water) with 0.1 per cent dextrose 73 hours. . 



Control analysis, same lot as Nos. 53 to 54, in sea water until end of experiment 



No. 54 



Ash in 

 dried 

 meats. 



Per cent. 

 31.93 

 37.55 

 22.00 

 37-75 

 32-95 

 31.50 

 33.90 



34.30 

 31.63 



34.84 



37.60 



35-75 

 36-35 

 19.90 



37.48 

 23-55 

 36-73 



Glyco- 

 gen in 

 dried 



meats. 



Per cent. 



7-79 



8-75 

 10-79 

 10-57 



9-90 

 12-70 



8-98 



4- 30 

 3-83 

 4.03 



4-54 

 5.36 

 5.41 



3.69 



4-45 

 4- 13 



Glyco- 

 gen in 

 ash-free 

 solids. 



Per cent. 

 11.50 

 13.08 

 13-84 

 14.64 

 14.76 

 ■ 18.53 

 13.38 



6-39 



S-60 

 S-36 



S-64 



7-08 

 7-28 

 6-75 



5.90 



S.82 

 6.50 



69571°— 18- 



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