Effects of fish meal replacement with Chlorella meal on growth performance, pigmentation, and liver health of largemouth bass (Micropterus salmoides)

High replacement of fishmeal by Chlorella meal affects intestinal microbiota and the potential metabolic function in largemouth bass (Micropterus salmoides)

“…The gut samples from FM100, FM75 and FM50 groups overlapped closely but separated from those from FM25 and FM0 groups, indicating the significant effect on gut microbial community. Combined with previous results in largemouth bass (Xi et al, 2022) and other species on growth performance and feed utilization, this study further demonstrates the alterations of gut and the potential negative effects caused by high proportions of plant protein inclusion. In some aquaculture species, partial substitutions of fishmeal by plant ingredients (such as soy protein concentrate) negatively affects gut morphology by decreasing mucosal fold width and shortening the microvilli in the gut of fish (Green et al, 2013;Larios-Soriano et al, 2022).…”

“…It is a common practice to utilize microalgae as either a protein source ingredient to reduce the use of fishmeal without compromised performance and to achieve protein source sustainability, or to include it as a low-level dietary supplement to improve fish health (Bai et al, 2001;Perez-Velazquez et al, 2019;Van Vo et al, 2020). Our recent study reveals that partial fishmeal replacement by Chlorella meal in diets contributes to better growth (Xi et al, 2022). However, the effects of replacing fishmeal with Chlorella meal on fish gut microbiota remain to be explored.…”

“…FM100 represents the fishmeal diet without Chlorella meal; FM75, FM50, FM25, and FM0 represent the fishmeal feed with 25, 50, 75, and 100% fishmeal replacement by Chlorella meal, respectively. (Xi et al, 2022). In addition, the elevation of gene pathways dedicated to amino acid metabolism and lipid metabolism further indicates the gut microbiota involved in the fermentative processes.…”

“…For largemouth bass, M. salmoides, replacing fishmeal with alternative protein sources and/or improving the utilization was the object of most studies (Sampaio-Oliveira and Cyrina, 2008;Ding et al, 2015;He et al, 2020;Liu et al, 2021;Li et al, 2021b;Xu et al, 2022); however, few studies involved the use of microalgae such as Chlorella meal. Recently, a sister study revealed that fishmeal replacement with Chlorella meal can enhance the growth of largemouth bass and yellowness of fish body and dorsal muscle (Xi et al, 2022). However, 75% of total replacement of fishmeal by Chlorella meal in a basal diet led to lower feed efficiency and undesirable effects on fish health, suggesting that high fishmeal replacement by Chlorella meal could alter nutritional utilization and metabolism in the fish.…”

Evaluation of four novel protein sources as alternatives to soybean meal for two specifications of cage-farmed grass carp (Ctenopharyngodon idellus) deeds: Effect on growth performance, flesh quality, and expressions of muscle-related genes

“…Single-cell protein (SCP) has been reported as a good alternative to plant protein sources because of its accessibility (Vermeulen et al, 2012) and rich protein supplement (Ritala et al, 2017). Clostridium autoethanogenum protein (bacterioprotein, CAP) and chlorella powder (microalgae protein, CHP) are novel SCPs that have been preliminarily used as protein sources for largemouth bass (Xi et al, 2022), genetically improved farmed tilapia (GIFT, Oreochromis niloticus) (Maulu et al, 2021), and crucian carp (Carassius auratus) (Shi et al, 2015). Compared with plant protein sources, novel animal protein sources are characterized by a low carbohydrate content and high mineral and vitamin content, independent of seasonal and climatic variations and, thus, have been more studied as protein source substitutions (Liu et al, 2019).…”