Crassostrea gigas aquaculture depends on the capacity of hatcheries to produce microalgae to feed oysters. Alternative feeds for bivalves, such as the use of seaweeds single cell detritus (SCD), have been reported. However, this has not been tested as yet as a possible strategy for C. gigas hatcheries. This study was conducted to select an SCD as an alternative feed for C. gigas based on its effects on digestive activity, histomorphology, and microbiota. The seaweeds tested were Ulva lactuca, Ulva clathrata, and Porphyra sp. and compared with common feed consisting of microalgae Chaetoceros calcitrans and Isochrysis galbana. After 17 days of feeding, the mortality was 100% for oysters fed SCD of Porphyra sp., but oysters fed SCD of Ulva showed low mortality. Ulva SCDs were appealing for oysters, according to the filtration rate. Histomorphology of the epithelium height of oysters fed U. lactuca SCD was similar to that fed C. calcitrans. The ingested SCD modified the oyster’s microbiota composition, decreasing the alpha and beta diversity in oysters fed SCD of U. lactuca; however, species richness was similar to that of oysters fed microalgae. In oysters fed SCD, bacterial orders Vibrionales, Campylobacterales, and Clostridiales increased, whereas Pseudomonodales, Chromatiales, Rhizobiales, Sphingomonodales, and Burkholderiales decreased. The most abundant bacterial phyla Proteobacteria, Bacteroidetes, and Firmicutes were identified in all oysters independently of feed. Oysters fed with SCD decreased the lipase enzymatic activity, which is related to the low lipid content in SCD; however, the activity of enzymes involved in carbohydrate and proteases digestion increased in oysters fed U. lactuca SCD. These results suggest U. lactuca-derived SCD as a candidate for supplementation of C. gigas in future partial substitution tests.

Crassostrea gigas水产养殖取决于孵化场生产微藻喂养牡蛎的能力。已经报道了双壳类的替代饲料，例如使用海藻单细胞碎屑（SCD）。但是，这尚未作为长尾C孵化场的可能策略进行测试。进行这项研究的目的是根据SCD对消化活性，组织形态学和微生物群的影响，选择一种SCD作为C. gigas的替代饲料。测试的海藻是紫花苜蓿，紫花苜蓿和紫菜。并与微藻Chaetoceros calcitrans和Isochrysis galbana组成的普通饲料进行比较。进食17天后，饲喂Porphyra sp。SCD的牡蛎的死亡率为100％，但饲喂Ulva SCD的牡蛎的死亡率低。根据过滤速率，Ulva SCD吸引了牡蛎。饲喂U. lactuca SCD的牡蛎上皮高度的组织形态与饲喂C. calcitrans的相似。摄入的SCD改变了牡蛎的微生物群组成，降低了饲喂U. lactuca的SCD的牡蛎中α和β的多样性。然而，物种丰富度与饲喂微藻类的牡蛎相似。在喂食SCD的牡蛎中，细菌菌有弧菌，弯曲杆菌和梭菌增加，而假单脚，Chromatiales，根瘤菌，Sphingomonodales和Burkholderiales减少。最丰富的细菌门变形菌，拟杆菌和厚壁菌门的独立饲料的所有牡蛎进行鉴定。用SCD喂养的牡蛎降低了脂肪酶的酶活性，这与SCD中的低脂质含量有关。然而，喂食U.lactus SCD的牡蛎中参与碳水化合物和蛋白酶消化的酶的活性增加。这些结果表明，来源于U. lactuca的SCD可作为补充C. gigas的候选物。 在将来的部分替代测试中。