AUTHOR=Ye Bingcong , Gu Zhifeng , Zhang Xingzhi , Yang Yi , Wang Aimin , Liu Chunsheng 

TITLE=Comparative Effects of Microalgal Species on Growth, Feeding, and Metabolism of Pearl Oysters, Pinctada fucata martensii and Pinctada maxima

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.895386

DOI=10.3389/fmars.2022.895386

ISSN=2296-7745

ABSTRACT=In this study, P. f. martensii and P. maxima juveniles of two sizes (large and small) were fed with six different microalgae diets [I. galbana (I), Platymonas subcordiformis (P), Chaetoceros muelleri (C), I+P, I+C and P+C] to evaluate the differences in growth, feeding, and metabolism between two pearl oyster species. After 60-d of the rearing period, P. f. martensii and P. maxima fed with mixed microalgae showed a significantly higher relative growth rate (RGR) than those fed with single microalgae (P < 0.05). RGRs were significantly higher in P. f. martensii than those in P. maxima fed with the same diets (P < 0.05). The RGRs showed a decreasing tendency with the growth in both pearl oyster species. CRs of pearl oysters fed with mixed microalgae were significantly higher than those fed with single microalgae (P < 0.05), and CRs of P. f. martensii were significantly higher than those of P. maxima fed with the same diets (P < 0.05). Significantly lower respiration rates (RRs) were observed in small size P. f. martensii groups fed with I, P, and I+P diets, and all large P. f. martensii groups compared to P. maxima fed with the same diets (P < 0.05). Higher activities of amylase, cellulase, lipase, and pepsin in P. f. martensii were observed compared to P. maxima fed with the same diets at two sizes. The pepsin activities in P. maxima decreased with the growth, while there were no consistent pepsin activities of P. f. martensii with the growth. The carbonic anhydrase activities in P. maxima were significantly higher than those in P. f. martensii fed with the same diets (P < 0.05). The carbonic anhydrase activities were highest in the I+C diet group, followed by C+P and I+P, I, C, and P groups. Significant differences were observed among different diet groups in the same pearl oyster species (P < 0.05). Our results suggest that the lower CR and activities of digestive enzymes and higher RRs and activities of carbonic anhydrase may cause a lower growth rate of P. maxima compared to P. f. martensii.