Partial replacement of fishmeal with Clostridium autoethanogenum single‐cell protein in the diet for juvenile black sea bream ( Acanthopagrus schlegelii )

Abstract

Clostridium autoethanogenum protein (CAP) is a single‐cell protein derived from ethanol production and may have potential to become a substitute for fishmeal in aquafeeds. A 70‐day feeding trial was conducted with black sea bream (Acanthopagrus schlegelii) (mean initial weight 6.03 ± 0.09 g) to evaluate partial replacement of fishmeal with CAP in diets. Seven isonitrogenous and isoenergetic diets were formulated with graded levels of CAP (0, 4.85, 9.70, 14.55, 19.40, 38.80 and 58.20%) to replace fishmeal. The inclusion of CAP at all dietary levels tested did not significantly affect the growth performance (p > .05). Fish fed the CAP58.20% diet showed a significantly lower feeding rate, with significantly higher protein efficiency ratio and feed efficiency ratio compared with fish fed the other diets (p < .05). No statistical differences were found in dorsal muscle and whole‐body compositions. Total superoxide dismutase in serum of fish fed CAP58.20% diet was significantly lower compared with that of the control. Malondialdehyde, catalase, total antioxidant capacity and digestive enzyme activities revealed no significant differences among dietary treatments. Phosphorus retention efficiency significantly increased, and phosphorus discharge showed a downward trend with increasing CAP inclusion levels. In conclusion, the results indicated that CAP is a safe and effective alternative protein source, which can replace fishmeal in the diet of black sea bream up to 58.20%, without adverse effects on growth performance, antioxidation and digestive enzyme activity. This study has shown the potential of converting industrial waste into a high protein feed ingredient for aquafeeds.

Effects of Dietary Inclusion of Clostridium autoethanogenum Protein on the Growth Performance and Liver Health of Largemouth Bass (Micropterus salmoides)

“…It showed that high levels of CAP substitution affected the antioxidant capacity of juvenile largemouth bass, leading to the accumulation of free radicals, which damaged liver health. Inversely, replacing fish meal with CAP in feed for juvenile black sea bream did not affect the antioxidant capacity of the liver tissue (Chen Y. et al, 2020). This conflicting result may be due to different fish and protein-processing methods used, which may have an impact on the availability and digestibility of nutrients.…”

“…However, when the level of CAP replacement fish meal exceeds 50%, it will have a negative impact on the growth performance of largemouth bass. On the one hand, the content of lysine in CAP is low, and lysine has a great influence on the growth center (Chen Y. et al, 2020;Wang et al, 2020). Therefore, the relative lack of lysine content in feeds with high CAP replacement levels may cause the growth performance of the D4 group to decline.…”

“…As a pretty novel SCP, current preliminary studies only evaluate the effects of the supplementation with CAP on the growth, digestion, and antioxidant capacity of grass carp (Ctenopharyngodon idella), (Wei et al, 2018), Jian carp (Cyprinus carpio var. Jian), (Li M. Y. et al, 2021), tilapia (GIFT: Oreochromis niloticus), (Maulu et al, 2020(Maulu et al, , 2021, and black sea bream (Acanthopagrus schlegelii), (Chen Y. et al, 2020), but few studies to date have focused on the liver health of fish and the regulation mechanism of dietary inclusion of CAP, especially in high inclusion levels.…”

Transcriptional control of Clostridium autoethanogenum using CRISPRi

“…Gas fermentation by carbon fixing chemolithoautotrophic organisms, such as Clostridium autoethanogenum , offers an opportunity to recycle carbon and harness energy from synthesis gas (syngas) generated through gasification of organic biomass (such as agricultural waste, unsorted and nonrecyclable municipal solid waste or industrial waste) or industrial off-gases. Carbon recycled by C. autoethanogenum can be applied toward the production of transportation fuels, nutritionally valuable food additives for animal feed and chemicals ( 4–6 ). After a decade of research and progressive scale-up, the technology has been commercialized with the first plant operating successfully, producing fuel-grade ethanol, since 2018; additional units are currently under construction ( 7 ).…”

Nontraditional Feedstuffs as an Alternative in Poultry Feed

“…The oil content in bacteria and yeast is high and rich in unsaturated fatty acids. Chen et al [51] concluded that SCP produced by Chlostridium autoethanogenum had 88.93% crude protein and most of essential amino acids were higher than that of fish meal.…”