Study assesses quality changes to Pacific white shrimp in a simulated live supply chain

Results suggest that the highest mortality (12%) occurred after live transport

Live shrimp like the Pacific white shrimp (Penaeus vannamei) are favored by consumers in several Asian countries for sensory qualities and nutritional retention. Thus, in “farm-to-fork” live supply chains (including harvesting, transport, rest and sale), maximizing shrimp survival and maintaining quality are critical.

When shrimp move through a live supply chain, they encounter several stress conditions that are likely to combine to trigger physiological deterioration, loss of muscle quality and microflora imbalances. Previous studies have highlighted factors influencing post-harvest quality loss in shrimp and fish, such as prolonged transport, overcrowding, oxygen fluctuation, rest periods before shipment and temperature variations during transport. Meanwhile, the gut microecosystem serves as a key regulator of host activity, and the proposed “gut-muscle axis” theory provides a fundamental basis for understanding the interactive effects between the gut microbiota and muscle quality. Various studies have reported that dietary interventions can improve muscle quality by regulating gut microbiota-mediated nutrient metabolism and immune responses.

The gut microecosystem undergoes stress-induced changes that impair nutrient absorption and antioxidant functions, leading to muscle deterioration. Recent studies on shrimp gut microbiota have focused on tracking various stressful situations in the culture process, such as salinity changes, nutritional composition, growth temperature and probiotic feeding. Overall, most studies to date have focused on isolated stages of the supply chain or single stress factors, with significant gaps in understanding how different stages of the live supply chain affect muscle quality, microbiota and their interactions, particularly in P. vannamei.

This article – summarized from the original publication [Zhang, P. et al. 2025. Changes in Muscle Quality and Gut Microbiota of Whiteleg Shrimp (Penaeus vannamei) Within a Live Supply Chain. Animals 2025, 15(10), 1431] – reports on a study that tracked the critical phases of the live shrimp supply chain, including post-harvest, post-transport, post-rest and simulated sales under ambient temperature and low temperature.

How phospholipid sources impact growth, health and gut microbiota of female Pacific white shrimp

Study setup

Pond-reared P. vannamei (14.2 ± 2 grams) were harvested at Ningbo Zhengda Agriculture Co., Ltd. (Ningbo, China), and 1,220 healthy animals were selected and transported to Ningbo University’s Meishan Campus for the study.

Various phases of the practical live supply chain for white shrimp distribution were simulated and tracked in the lab, including post-harvest (PH), post-transport (PT), post-rest (PR), and simulated sales phases [ambient temperature (AT), 29 degrees-C ± 0.3 degrees-C, and low temperature (LT), 23 degrees-C ± 0.3 degrees-C]. The cumulative survival rate, muscle quality parameters [i.e., color, texture, pH and other parameters] and gut microbiota were assessed.

By integrating and analyzing these datasets, this research aimed to investigate changes in the quality and intestinal bacterial communities of P. vannamei throughout the live supply chain, focusing particularly on the effects of temperature fluctuations. Based on the analysis of muscle quality and gut microbiota changes in P. vannamei in the live supply chain, this study provides critical control points and key microbial biomarkers associated with high muscle quality, aiming to improve the survival rates and extend shelf life in post-harvest and aquaculture management.

Results and discussion

As the simulated supply chain progressed, the cumulative survival rates of the shrimp gradually declined (Fig. 2A). At PT and PR, the survival rates were 88.19 percent ± 0.33 percent and 82.48 percent ± 0.33 percent, respectively. During the simulated sales phase, both the AT and LT groups exhibited similar trends: From S0 to S24, shrimp mortality increased gradually and after S24, the survival rates stabilized. Between S0 and S48, the AT group demonstrated a significant decrease in the survival rate from 81.26 percent ± 0.20 percent to 67.81 percent ± 1.75 percent; similarly, the LT group’s survival rate decreased from 82.48 percent ± 0.33 percent to 75.43 percent ± 1.43 percent during the same period. At S8, the survival rate was significantly higher in the AT group than in the LT group, but over S24–S48, the LT group’s survival rates remained consistently and significantly higher than those of the AT group.

Fig. 2C shows changes in muscle lactate content over time. Lactate content increased from 8.41 ± 1.25 μmol/gram at PH to 31.48 ± 1.02 μmol/gram at PT, followed by a sharp decrease at PR. From PR to S48, lactate levels remained relatively stable, fluctuating around 10 μmol/gram in both AT and LT groups. Fig. 2D illustrates changes in muscle TBARS content (thiobarbituric acid reactive substance; formed as a byproduct of lipid oxidation) throughout the live supply chain.

The cumulative survival rate is a key indicator of transport efficiency, reflecting stress damage in shrimp. The high mortality rates observed during the transportation phase are likely attributable to rough handling, high stocking density, localized hypoxia and physiological injuries induced by harvesting, all of which impose severe stress that may exceed the shrimp’s adaptive capacity. After the 24-hour mark of simulated sales, the cumulative survival rate stabilized, likely due to the activation of adaptive strategies in shrimp, which gradually restored physiological homeostasis, leading to a reduction in mortality.

TBARS represent an important indicator for evaluating lipid oxidation and flavor deterioration. Their increase is primarily due to the oxidation of polyunsaturated fatty acids (PUFAs) in cell membranes, leading to the formation of toxic peroxides that can induce apoptosis (cell death) and activate immune responses, contributing to muscle degradation. TBARS levels remained low throughout the live supply chain and did not reach thresholds known to affect flavor, which is likely due to the inherently low lipid content of P. vannamei.

Color and texture are important quality parameters for shrimp, and consumers prefer brighter, firmer and more elastic muscles. In our study, muscle brightness deteriorated at PT, which is consistent with findings related to crowding stress. Muscle texture deteriorated primarily due to pH drop, release of the hormone cortisol and activation of protease enzymes. During the sales phase, texture worsened in the AT group, but was less affected in the LT group, possibly due to inhibited protease enzyme and phenoloxidase (PO, a major defense system in many invertebrates) activity at cold temperatures.

Predominant phyla in shrimp intestines included Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes, consistently with previous studies. The high abundance of Gammaproteobacteria in adult shrimp intestines (up to 40 percent) is characteristic of gut microbiome disruptions. Actinomycetes are crucial to intestinal homeostasis, and their rapid growth suggests potential gut microbiome issues. This study also found that the dominance shifted from Proteobacteria (at PH) to Actinobacteria (at PT) and Firmicutes (at PR).

It is essential to integrate and discuss various indicators to evaluate the changes in the live supply chain and derive practical insights from these changes. Among the various stages of the supply chain, the transportation phase exhibited the greatest reduction in survival rate, during which the shrimp countered the associated stress by enhancing gut microbiota-mediated antioxidant defenses, stress-resistance mechanisms, and energy metabolism pathways. Meanwhile, we found that during the simulated marketing period, muscle quality changed, and the transport, 24-hour sales and 40-hour sales stages were identified as three potential critical control points. These key points can be used to optimize conditions or adjust sales strategies in the live shrimp supply chain to maximize shrimp quality and shelf life.

Moreover, post-transport rest effectively alleviated transport stress and gut microbiota dysfunction, indicating that a standardized rest procedure is beneficial for shrimp survival, especially during longer-distance transport. During the simulated sales period, the LT group exhibited higher survival rates and better-quality parameters. These findings demonstrate that a low-temperature environment enhances shrimp stress resistance and stabilizes the interactions between the gut microbiota and the host.

Overall, maintaining 23 degrees-C in the LT group is an effective, feasible and industry-aligned strategy for improving live shrimp survival and quality. Notably, the enrichment of Xanthomonadales and Oscillospirales in the LT group, along with their positive correlation with survival rates and muscle quality indicators, suggests that these bacterial taxa could serve as biomarkers for assessing shrimp adaptation to low temperatures and the maintenance of muscle quality. Study results provide essential tools and new perspectives for future gut microbiota-based muscle quality control strategies.

Perspectives

In this study, the transport, 24-hour sales and 40-hour sales stages were identified as three potential critical control points. Meanwhile, post-transport rest was effective in relieving transport stress and is recommended for standardization in the live supply chain. Notably, the LT group (23 degrees-C) showed higher survival, resulted in higher muscle hardness and pH, and reduced gut-mediated metabolic levels, making it an effective and feasible solution.

We speculate whether the improved physiological condition of the LT group might be related to the enrichment by the bacterial orders Xanthomonadales and Oscillospirales, which could serve as biomarkers for muscle quality. As this study focused on short-distance transport, further validation over longer distances is needed. In the future, integrating water quality parameters, shrimp physiological indicators, and metabolomics will help clarify host-microbiota interactions, thereby advancing microbiota-based quality control strategies in the live supply chain and aquaculture.

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