How Plant-Based Diets Affect Growth in Giant Freshwater Prawns

Greg Howard
2nd March, 2024

How Plant-Based Diets Affect Growth in Giant Freshwater Prawns

Classification of all genes annotated in KOG that were expressed in hepatopancreas of fast-growing shrimp (F-shrimp) and slow-growing shrimp (S-shrimp). The X-axis represents the classification name of the 26 KOG groups, and the Y-axis represents the percentage of genes in each annotated KOG group.

Image adapted from: Phonsiri et al. / CC BY (Source)

Key Findings

  • In a study at Suranaree University, prawns fed soy-based diets showed varied growth rates
  • Fast-growing prawns were better at turning soy into body protein than slow-growers
  • Fast-growers had genes linked to metabolism and immunity more active than slow-growers
In aquaculture, the search for sustainable and cost-effective feed alternatives is a pressing issue, as traditional fishmeal-based diets are costly and not environmentally sustainable. A recent study by researchers at the Suranaree University of Technology[1] has shed light on how the giant freshwater prawn, Macrobrachium rosenbergii, responds to a plant-based diet, specifically one based on soybean meal (SBM). This research could potentially address the problem of finding an efficient, sustainable feed that supports the growth of prawns, which is a significant step in aquaculture. The study focused on the individual growth response of 200 prawns to a diet of SBM over a period of 90 days. Researchers measured the specific growth rate (SGR) of each prawn to categorize them into two groups: fast-growing (F-shrimp) and slow-growing (S-shrimp). The top 5% fastest growers and the bottom 5% slowest were then analyzed more closely to understand the physiological and metabolic differences contributing to their growth rates. Interestingly, while there were no notable differences in the shrimp's haemolymph chemistry—a fluid equivalent to blood in humans—the F-shrimp group had a higher protein composition in their carcass. This indicates that the F-shrimp were more efficient at converting the soybean meal into body protein, a process known as protein anabolism. To delve deeper, the researchers used RNA sequencing (RNA-Seq) and real-time reverse transcription polymerase chain reaction (qRT-PCR) to compare the expression levels of genes in the hepatopancreas, an organ similar to the liver in vertebrates, which plays a crucial role in metabolism and digestion. They found that F-shrimp had upregulated expression of genes encoding enzymes that are involved in physiological and metabolic processes. This suggests that these enzymes might be key to how well the prawns utilized the SBM diet for growth. The study also observed differences in the immune system responses between the F-shrimp and S-shrimp, with various differentially expressed genes (DEGs) associated with immunity. This finding is consistent with previous research on black tiger shrimp, which identified changes in gene expression related to immune function under ammonia stress[2]. The ability to maintain a robust immune system while on a plant-based diet is crucial for the health and productivity of aquaculture species. Another important aspect of the study was the observation that several housekeeping genes, which are essential for basic cellular function, were upregulated in the S-shrimp. This could suggest that the S-shrimp were diverting energy to maintain basic functions rather than growth, a hypothesis that would need further investigation. The research at Suranaree University of Technology builds upon earlier findings that also explored growth performance in fish. A study on zebrafish showed that a plant protein-based diet affected the expression of growth-related genes in muscle tissue[3]. Similarly, the current study suggests that diet can significantly influence gene expression associated with growth in prawns as well. Moreover, the concept of nutritional programming, as observed in Nile tilapia[4], where early nutritional stimuli influenced the metabolic programming of fish, may also be relevant here. Although the prawn study did not involve early life stage intervention, the principle that nutrition can have long-lasting effects on metabolism is echoed in the observed individual differences in growth response. In summary, the Suranaree University of Technology study has revealed that individual prawns respond differently to a soybean meal-based diet. The findings suggest that certain physiological and metabolic processes, as well as immune function, play a role in how effectively prawns can utilize plant-based diets for growth. This research is a step forward in the quest for sustainable aquaculture practices, as it points towards the possibility of selectively breeding or nutritionally programming prawns to thrive on more sustainable, plant-based feeds.

NutritionGeneticsAnimal Science

References

Main Study

1) Differential responses of hepatopancreas transcriptome between fast and slow growth in giant freshwater prawns (Macrobrachium rosenbergii) fed a plant-based diet.

Published 29th February, 2024

https://doi.org/10.1038/s41598-024-54349-6

Related Studies

2) Transcriptome reveals involvement of immune defense, oxidative imbalance, and apoptosis in ammonia-stress response of the black tiger shrimp (Penaeus monodon).

https://doi.org/10.1016/j.fsi.2018.09.026

3) Growth response and expression of muscle growth-related candidate genes in adult zebrafish fed plant and fishmeal protein-based diets.

https://doi.org/10.1089/zeb.2012.0823

4) Glucose Injection Into Yolk Positively Modulates Intermediary Metabolism and Growth Performance in Juvenile Nile Tilapia (Oreochromis niloticus).

https://doi.org/10.3389/fphys.2020.00286


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