Procambarus Clarkii Research Articles

Parabens and triclosan in red swamp crayfish (Procambarus clarkii) from China: Concentrations, tissue distribution and related human dietary intake risk

Parabens (PBs) and triclosan (TCS) are commonly found in pharmaceuticals and personal care products (PPCPs). As a result, they have been extensively found in the environment, particularly in aquaculture operations. Red swamp crayfish (Procambarus clarkii) consumption has significantly risen in China. Nevertheless, the levels of PBs and TCS in this species and the associated risk to human dietary intake remain undisclosed. This study assessed the amounts of five PBs, i.e., methyl-paraben (MeP), ethyl-paraben (EtP), propyl-paraben (PrP), butyl-paraben (BuP) and benzyl-paraben (BzP), as well as TCS in crayfish taken from five provinces of the middle-lower Yangtze River. MeP, PrP and TCS showed the highest detection rates (hepatopancreas: 46–86 %; muscle: 63–77 %) since they are commonly used in PPCPs. Significantly higher levels of ∑5PBs (median: 3.69 ng/g) and TCS (median: 7.27 ng/g) were significantly found in the hepatopancreas compared to the muscle (median: 0.39 ng/g for ∑5PBs and 0.16 ng/g for TCS) (p < 0.05), indicating bioaccumulation of these chemicals in the hepatopancreas. The estimated daily intake values of ∑5PBs and TCS calculated from the median concentrations of crayfish were 6.44–7.94 ng/kg bw/day and 11.4–14.0 ng/kg bw/day, respectively. Although no health risk was predicted from consuming crayfish (HQ <1), consumption of the hepatopancreas is not recommended.

Invisible invaders: range expansion of feral Neocaridina davidi offers new opportunities for generalist intracellular parasites

AbstractThe release of ornamental pets and associated pathogens outside their native range might directly or indirectly impact the recipient community. In temperate regions, e.g., central Europe, feral freshwater species of tropical and sub-tropical origins are mainly constrained to thermally polluted waters and thermal springs. However, species with high environmental plasticity and reproduction rates, such as the shrimp Neocaridina davidi, may adapt to colder water regimes over time. A widening thermal niche may eventually overcome thermal barriers, further expanding the range and enhancing transmission opportunities for host generalist parasites. This study assesses the observed (field observations) and theoretical (species distribution models) range expansion of N. davidi and associated parasites in Europe. We report three newly established N. davidi populations from thermally polluted waters in central Europe (Germany, Hungary, and Slovakia) and provide further evidence of its range expansion into colder environments. Species distribution models predict thermally suitable habitats in the Mediterranean and a foreseeable expansion into Western Europe and the Balkans by 2050. We confirm the presence of the microsporidian parasite Ecytonucleospora hepatopenaei in feral N. davidi populations across Europe and expand the list of microsporidians found in this host from two to four. Furthermore, we provide the first evidence of parasite spillover from/to the invasive crayfish Procambarus clarkii, suggesting that parasite exchange with native biota might be possible. Such possibility, coupled with an ongoing range expansion of N. davidi bolstered by human-mediated introductions and climate change, will likely exacerbate the impact on native biota.

Effects of luteolin supplementation on growth, histology, antioxidant capacity, non−specific immunity and intestinal microbiota of the red swamp crayfish (Procambarus clarkii)

To investigate the effects of luteolin (LUT) on the growth, antioxidant capacity, non−specific immunity and intestinal microbiota of the red swamp crayfish (Procambarus clarkii), 300 individual P. clarkii (4.17 ± 0.50g average body weight and 50.19 ± 1.40mm average body length) were randomly divided into five groups and fed with LUT doses of 0mg/kg (CG), 50mg/kg (LG50), 100mg/kg (LG100), 300mg/kg (LG300), and 500mg/kg (LG500) for 8 weeks, respectively. Firstly, the results demonstrated that survival rates were significantly higher in all LUT added groups compared to the CG group, with no significant differences in hepatosomatic index, feed coefficient and muscle components. Secondly, dietary supplementation with LUT improves the growth performance of P. clarkii. Thirdly, histological observations displayed that the hepatopancreas and intestine tissues were not damaged in the LUT−supplemented group, and the length of intestinal folds was significantly increased in the LG100 and LG300 groups. Fourthly, the LG50, LG100, and LG300 groups produced significantly increased hepatopancreatic antioxidant enzyme activities and hemolymph immune indicators compared with the CG group. In all experimental groups, malondialdehyde contents were significantly reduced, as were aspartate aminotransferase and alanine aminotransferase activities. Adding LUT to the diet specifically improved the structure and optimized the function of the gut microbiota. Compared to the CG group, the LG group (100mg/kg) displayed a significant increase in the index of Chao1 and Observed species, an increase in the relative abundance of Proteobacteria and Actinobacteria, a decrease in the ratio of Bacteroidetes to Firmicutes, and an increase in the abundance of Thermomonas, Turicibacter, Bdellovibrio and Enterococcus. PICRUSt analysis demonstrated a significant improvement in the KEGG pathway associated with isoflavone biosynthesis in the LG group. In conclusion, the present study confirms that dietary supplementation with 50−300mg/kg LUT favors growth, non−specific immunity and antioxidant function in P. clarkii, with optimal additions ranging from 102−165mg/kg. Furthermore, it optimized gut microbiota function, suggesting that LUT can be used as a potential feed additive for P. clarkii. These findings provide new insights for healthy P. clarkii culture.

Prevalence of the crayfish plague pathogen in red swamp crayfish populations in western France: How serious is the risk for the native white-clawed crayfish?

The crayfish plague pathogen Aphanomyces astaci has been implicated in a number of mass mortalities and irreversible population declines of native crayfish across Europe. At present, the reservoirs of the pathogen in Europe are mainly populations of invasive North American crayfish species. In southwestern Europe, including France, a particularly widespread invader is the red swamp crayfish Procambarus clarkii. Recent distribution data confirm that P. clarkii is present in at least 75 French departments, i.e. more than 78% of those in metropolitan France. We analysed the prevalence and pathogen load of A. astaci in 42 populations of this species in western France (Nouvelle Aquitaine region), where the species is most densely distributed, particularly in a wide range of environments around the Gironde estuary. The pathogen was detected by two different quantitative PCR assays in more than three quarters of the populations studied (34 out of 42); 163 out of 480 analysed crayfish individuals tested positive for the presence of A. astaci. In most cases, individual infection levels were very low, detectable with quantitative PCR but not sufficient for pathogen genotyping. In seven P. clarkii individuals from four populations, however, we were able to assess A. astaci variation by microsatellite markers and sequencing of mitochondrial markers. All these host specimens carried A. astaci genotype group D, haplotype d1, which has caused the majority of crayfish plague outbreaks in neighbouring Spain. In contrast, the French outbreaks genotyped to date (including eight newly analysed in this study) were mostly caused by strains of genotype group B, specific to the signal crayfish Pacifastacus leniusculus. Haplotype d1 found in P. clarkii was involved in one of the newly characterised outbreaks. Our study confirms that P. clarkii is a potentially important reservoir of the crayfish plague pathogen in France, but not the main source of the pathogen in mass mortalities of A. pallipes, probably due to different ecological requirements of the different invasive host crayfish. However, as P. clarkii continues to spread, the threat posed by this species to native crayfish is likely to increase.

Toxic mechanisms of nanoplastics exposure at environmental concentrations on juvenile red swamp crayfish (Procambarus clarkii): from multiple perspectives

Nanoplastics pollution has emerged as a global issue due to its widespread potential toxicity. This study delved in to toxic effects of nanoplastics on juvenile P. clarkii and molecular mechanisms from perspectives of growth, biochemical, histopathological analysis and transcriptome level for the first time. The findings of this study indicated that nanoplastics of different concentrations have varying influence mechanisms on juvenile P. clarkii. Nanoplastics have inhibitory effects on growth of juvenile P. clarkii, can induce oxidative stress. The biochemical analysis and transcriptome results indicated that 10mg/L nanoplastics can activate the antioxidant defense system and non-specific immune system in juvenile P. clarkii, and affect energy metabolism and oxidative phosphorylation. While 20mg/L and 40mg/L have a destructive influence on the immune function in juvenile P. clarkii, leading to lipid peroxidation and oxidative damage, and induce apoptosis, can affect ion transport and osmotic pressure regulation. The findings of this study can offer foundational data for delving further into impacts of nanoplastics on crustaceans and toxicity mechanism.

Morphology-based selective breeding strategy analysis for abdominal meat yield in Procambarus clarkii

The edible portion of Procambarus clarkii mainly consists of the abdominal muscles, highlighting the genetic enhancement of abdominal meat yield in breeding. To explore a selective breeding strategy for abdominal meat yield, the correlation of morphological characteristics with abdominal meat yield based on five P. clarkii populations collected from its major production areas in China was analyzed and an optimal prediction model was constructed for predicting abdominal meat yield. With the analyses of P. clarkii morphological characteristics, Fulton's condition factor (K), which had a strong negative correlation (-0.800 in males and - 0.705 in females) with abdominal meat yield and the advantage of not requiring the sacrifice of breeding candidates, was eventually selected as the morphological predictor. And the optimal prediction model constructed based on K value was a quadratic curve, with R2 values of 0.684 for males and 0.590 for females, and correlation coefficients of 0.827 and 0.768 between observed and predicted values for males and females, respectively. The results of the abdominal meat yield selective breeding experiment, utilizing the optimal prediction model, demonstrated that the breeding population exhibited favorable morphological variation as expected. These findings provide a morphology-based selection strategy for breeding the abdominal meat yield of P. clarkii.

Transcriptomic analyses provide new insights into immune response of the Procambarus clarkii intestines to Aeromonas hydrophila challenge

In recent years, the death rate of Procambarus clarkii increased sharply due to pathogenic bacterial infections, leading to huge economic losses. To determine the immune response of the intestinal tissues of P. clarkii to bacterial infections, we compared the immune indexes, histopathological damage, and transcriptome data of the control and Aeromonas hydrophila-infected P. clarkii. With the injection of A. hydrophila, it was found that intestinal mucosal folds increased, intestinal villi showed obvious vacuolation, and the tissue structure changed significantly. The results of non-specific immunoenzyme activity showed that the Total protein (TP) content was significantly lower than that of the control group at 24 h, and the Acid phosphatase (ACP) and Alkaline phosphatase (AKP) activities in the treatment group showed a significant increasing trend (p < 0.05). In terms of the transcriptome, an average of 22,927,523 clean reads and 27,866 genes were found in the control and treatment groups through gene assembly and annotation. Among these genes, 567 were identified as differentially expressed genes (DEGs), of which 501 were up-regulated and 66 were down-regulated. Quantitative-polymerase chain reaction (qPCR) analysis of six randomly selected genes was used to verify the RNA-sequencing results. The Gene Ontology enrichment analysis revealed that the DEGs were primarily involved in cell processes, metabolic processes, and biological regulation, while the Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that these DEGs were involved in tyrosine metabolism, glycosphingolipid biosynthesis—ganglionic series, and nitrogen metabolism. We studied the tyrosine metabolic pathway and found that it contributes to the immune defense mechanism of P. clarkii. The results of our study provide important insights into the intestinal immune response of P. clarkii to A. hydrophila infection.

First record of the semi-aquatic invasive plant Crassula helmsii in the Iberian Peninsula and its link to potential dispersal drivers

AbstractAquatic neophytes are among the most harmful invasive species worldwide. Here we report the finding of the semi-aquatic invasive plant Crassula helmsii, naturalized in a freshwater reservoir that provides water to the large city of A Coruña, NW Spain. To better understand the extent and potential environmental correlates of C. helmsii invasion, we recorded the presence and frequency of C. helmsii in its emerged and floating mat forms at twelve sampling sites along the reservoir margins, and characterized the soil characteristics, plant community and environmental factors. Crassula helmsii is dispersed by fragmentation of the stems, potentially aided through shredding by local fauna such as the invasive crayfish Procambarus clarkii. We hypothesize that this could be a case of an invasional meltdown, when multiple invasive species facilitate one another and have synergistic effects on native ecosystems. The emerged form of C. helmsii was found in ten out of twelve sites with a mean cover value of 9.8 ± 10.4% (mean ± SD). We found no correlation between frequency of the emerged form of C. helmsii and abundance of Procambarus clarkii, but frequency of the emerged form of C. helmsii increased with higher soil nitrogen and vascular plant richness. We outline emergency actions for management of C. helmsii at this stage of the invasion, focusing on containment and avoiding spread to nearby water bodies.

Dietary phosphatidylcholine requirements of red swamp crayfish (Procambarus clarkii)

Dietary phosphatidylcholine requirements of red swamp crayfish (Procambarus clarkii)

Stress conditions extend maternal care and delay juvenile development in crayfish

Abstract Maternal care in crayfish has been extensively studied, but little is known of its response to environmental factors. We studied the duration of maternal care and its association with the juvenile development of marbled crayfish Procambarus virginalis in adverse environmental conditions. We exposed females with developmental stage 3 juveniles to environments of low water volume (LW) with food provided, low water volume with no feed (starvation) (LWS), and low water volume without feeding plus an intruder (red swamp crayfish male) (LWSI). A control group with standard water level/feed conditions was included for comparison. Groups were monitored for up to 90 days. The LWS group showed significantly prolonged maternal care (~65 days) as indicated by an extended attachment phase, delayed moulting of mothers (~53 days), and retarded juvenile development. In the LWSI group, conflict precluded extended maternal care. Low use of shelter and feeding was evident under all stress conditions. The results showed that crayfish females modify maternal care in accordance with conditions, providing a longer period of safety for offspring under adverse circumstances. It is possible that the expression of maternal pheromones can manipulate the developmental rate in juveniles, a topic for future research.

The Influence of Shelter Type and Coverage on Crayfish (Procambarus clarkii) Predation by Catfish (Silurus asotus): A Controlled Environment Study.

Procambarus clarkii is adept at using natural shelters and caves to evade attacks from predators. However, the concealment abilities and mechanisms of P. clarkii for different types of shelters under predation pressure have not yet been reported. In this study, laboratory experiments were carried out to determine the effects of different coverages (25%, 50%, and 75%) and different combinations (I-VII) of three types of shelters (PVC pipes, water grass, and stone) on the predation rhythm, behavior, and abilities of Silurus asotus on P. clarkii. The results indicated that the predation of S. asotus on P. clarkii exhibited significant rhythmicity under shelter conditions, excluding PVC pipes, 75% stone, and combination VI. Among the three types of shelters, PVC pipes provided the strongest concealment, followed by stone and water grass. With the increase in shelter coverage, the anti-predation ability of P. clarkii continued to increase, and the optimal shade rate for water grass was 50%. In the different shelter combinations, the environmental complexity had little effect on the predation activity of S. asotus on P. clarkii. These findings demonstrated that the type and abundance of shelters in the wild environment can affect the predation rhythm and activities of S. asotus on P. clarkii.

Effects of Cheliped Amputation on the Personality of Crayfish.

Animal personality, which describes inter-individual differences and intra-individual consistency in behaviors across time and contexts, has been widely observed and has significance for both ecology and evolution. Morphological modifications, particularly during early life stages, may highly influence animal behavior in adulthood; thus, exploring this relationship can elucidate personality development throughout ontogeny. In this study, we reared juvenile crayfish (Procambarus clarkii) with different degrees of cheliped mutilation and explored their personality patterns, including exploration and aggression, when they reached sexual maturity. Male crayfish showed repeatability in exploration, and both sexes showed repeatability in aggression. We observed no significant correlation between the two behavioral traits, indicating the absence of behavioral syndromes. Moreover, exploration did not differ according to the type of mutilation, but crayfish with more intact chelipeds were more aggressive, and males were more aggressive than females. These results indicate that cheliped mutilation may modify the average levels of personality traits associated with competition or self-defense. Our study provides insights into how morphological modifications may shape animal personalities in adulthood.

Isolation and identification of intestinal cellulolytic bacteria from red swamp crayfish (Procambarus clarkii)

Red swamp crayfish (Procambarus clarkii) like to eat aquatic plants. The intestinal microorganism plays an important role in cellulose degradation and utilization. Isolating bacteria which can degrade cellulose from the intestines of P. clarkii can provide a theoretical basis for the development of probiotics in forage for P. clarkii. Three selective media including carboxymethyl-cellulose, microcrystalline cellulose, and cellobiose were used in plate cultures for 48h and then dyed with Congo red. It was found that 5 strains produced hydrolytic rings on 3 culture media at 48h. Based on the results of 16S rRNA molecular analysis, strains C, E, G, H, and M were identified as Citrobacter sp., Staphylococcus sp., Acinetobacter johnsonii, Shewanella sp., and Aeromonas caviae, respectively. Specifically, Staphylococcus sp. exhibited the strongest capacity for the degradation of cellulose. Shewanella sp. showed the strongest degradation capacity for cellobiose. Acinetobacter johnsonii and Shewanella sp. can degrade cellulose and are expected to be used as probiotic feed for P. clarkii. This study can provide a theoretical basis for the healthy culture of P. clarkii.

Concentrations, sources and health risk of bisphenols in red swamp crayfish (Procambarus clarkii) from South-Eastern China

Bisphenol analogs (BPs) are extensively employed in commercial and industrial products and they have been found in a variety of environmental matrices and human samples. The red swamp crayfish (Procambarus clarkii) has been a trendy food in China in recent decades. However, the levels of BPs in Chinese crayfish and the associated hazards of human exposure remain unknown. Thus, in this study, the levels of eight BPs in crayfish gathered from five major provinces engaged in crayfish within the Yangtze River Basin were analyzed. Additionally, the health risks for humans by ingesting crayfish were calculated. BPs were frequently detected in crayfish tissues, indicating the wide occurrence of these chemicals. In comparison to other substitutions, BPA remains the dominant bisphenol analog. Most of the BPs were observed to accumulate in the hepatopancreas compared to the muscle, so consuming the hepatopancreas of crayfish is not recommended. With the exception of BPS, the Estimated Daily Intakes (EDIs) of the remaining BPs exceeded the Tolerable Daily Intake (TDI) specified by the European Food Safety Authority (EFSA) by a factor of 1.75–69.0. The mean hazard index (HI) values exceeded 1 for both hepatopancreas and muscle in all provinces, and the mean HI values for hepatopancreas were significantly higher than those for muscle, indicating potential health risks for local consumers.

Histological morphology and gene expression in the digestive system of Procambarus clarkii

To unravel the intricate morphological structure and functional aspects of the digestive system in Procambarus clarkii, this study employed histology and transcriptome sequencing techniques for a comprehensive analysis of its digestive system. The investigation revealed that the digestive system of P. clarkii comprises the esophagus, stomach (including cardiac and pyloric regions), caeca, midgut, hindgut, and hepatopancreas. The esophageal lumen displayed an "X" shape, with clearly visible radial muscle bundles within the connecting tissues. The internal architecture of the stomach and intestines mirrored that of the esophagus. Notably, the pyloric region of the stomach exhibited a comb-like structure, which facilitated food selection and filtration. The caeca showcased a larger lumen within the intestines, while the hindgut displayed smaller folds. The hepatopancreas, representing the digestive glands, demonstrated predominant bilaterally symmetrical features, encompassing the midgut on both sides. It consisted of multi-stage branching hepatic ducts, crucial for digestion and absorption. Transcriptomic analysis of the digestive system revealed significant gene expression in the esophagus, stomach, caeca, midgut, hindgut, and hepatopancreas, with 23,006, 22,208, 23,485, 23,196, 22,781, and 21,375 genes expressed, respectively. Moreover, tissue-specific expression was observed in 161, 459, 374, 547, 337, and 1080 genes. Additionally, a subset of 447, 453, 553, 506, 433, and 711 genes exhibited high expression levels. Further analysis led to the identification of 36 digestive enzyme genes across six distinct digestive tissues, categorized into three groups: carbohydrate metabolism, lipid breakdown, and protein metabolism. In conclusion, this study provides a comprehensive understanding of the morphological structure, gene expression characteristics, and classification of digestive enzyme genes in the digestive system of P. clarkii. These findings lay a solid foundation for future investigations on the digestive physiology and food digestion in P. clarkii.

Inhibitory effects of glutathione peroxidase on microbial spoilage of crayfish (Procambarus clarkii) during refrigerated storage

The variety of enzyme-based biological preservatives is limited. This study evaluated the effects of glutathione peroxidase (GSH-Px) on the quality of crayfish during refrigerated storage by measuring the pH, total volatile basic nitrogen, trimethylamine, and microbial contamination in crayfish muscle simulation system. The results revealed that 0.3% GSH-Px (CK3) not only suppressed the degradation of nitrogenous substances but also decreased the contamination levels of total viable, Enterobacteriaceae, and Pseudomonas counts (P < 0.05). Furthermore, the populations of Lactococcus, Aeromonas, and Massilia differed in the CK3 group compared to the other groups (P < 0.05) at the end of the storage (day 15). Moreover, the principal coordinate analysis showed that the colony composition of CK3 stored for 15 days was similar to that of the control group stored for 10 days. Therefore, GSH-Px exhibits antibacterial activity against Gram-negative bacteria and has good application potential in freshwater aquatic product preservation.

Mechanical excavation of wetland habitat failed to eradicate invasive American red swamp crayfish (Procambarus clarkii) in Malta

Abstract Invasive crayfish are an important ecological concern in many freshwater ecosystems. Many efforts have been made to eradicate them, but there is very little documentation of the effectiveness of these efforts. Between 2019 and 2020, a restoration project funded by the European Regional Development Fund tried to eradicate invasive American red swamp crayfish Procambarus clarkii from the Fiddien valley system in Malta by mechanically excavating the valley's stream bed and exporting contaminated debris securely off‐site to a dry quarry. Three years post‐intervention, we systematically surveyed the valley system to explore the distribution and relative abundance of the invasive crayfish population. We placed traps in a stratified random sample of stream segments (both those that were included in the original restoration project and those that were not) and recorded catch per unit effort (crayfish caught per trap night) and the size/frequency distribution of crayfish caught. The invasive crayfish were still abundant in the upper reaches of the valley system, and, despite the excavation effort, crayfish were present at the highest relative abundance (4.3–14.8 CPUE, median = 12.3) within the restored area. Despite substantial effort and spending of more than 700,000 €, mechanical excavation did not eradicate invasive crayfish populations. We urge caution for future projects planning to attempt crayfish eradication using this approach and call for much greater impact evaluation, and at the very least post‐project monitoring, to ensure lessons can be learnt from such failures in future.

The first finding of the red swamp crayfish Procambarus clarkii in Greece calls for rapid measures

AbstractThis contribution presents the first record of the invasive non-native red swamp crayfish Procambarus clarkii (Girard, 1852) in Greece and the Balkans. The crayfish was found during a fish monitoring expedition in the lower reaches of the Vosvozis River, near the city of Komotini, Thrace (northeastern Greece). The finding of P. clarkii in Greece expands the southernmost geographical range of the species in the Balkans and calls for immediate actions in preventing its further expansion to other water bodies and towards strict control of aquarium trade.

Differentially expressed genes involved in immune pathways following Vibro parahaemolyticus challenge: A study on red swamp crayfish Procambarus clarkii

This study conducted a comprehensive analysis of the damage mechanism of Vibrio parahaemolyticus (V. parahaemolyticus) on crayfish, utilizing pathological section observations, biochemical indicator detection, and transcriptomics analysis. Histopathological examination showed fragmentation of the gill lamellae, spotted pigment deposition on the branchial membrane, degeneration of epithelial cells, and disruption of the normal structure of gill tissues. Biochemical tests indicated a significant decrease in the activity of antioxidant-related enzymes in crayfish injected with V. parahaemolyticus compared with the phosphate-buffered saline group. Transcriptomics analysis identified 2307 upregulated and 1721 downregulated differentially expressed genes (DEGs). Gene ontology enrichment analysis highlighted that DEGs were primarily involved in the regulation of lipid metabolic processes, cellular nitrogen compound biosynthesis and metabolic processes, and the negative regulation of neuron death. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed significant enrichment in N-glycan biosynthesis, fatty acid metabolism, and the mTOR signaling pathway. Gene set enrichment analysis indicated pathways related to immunity and oxidative stress, including oxidative phosphorylation and tyrosine metabolism. Quantitative reverse transcription–polymerase chain reaction results for selected genes involved in the oxidative phosphorylation pathway and immune-related genes corroborated the RNA-Seq trends, confirming the transcriptomics data's reliability. The findings suggest that infection with V. parahaemolyticus leads to excessive oxidative stress due to bacterial proliferation, overwhelming the crayfish's antioxidative defense. This causes a continuous increase in reactive oxygen species levels, leading to irreversible damage to the oxidative phosphorylation and innate immune systems. This study elucidated the mechanism of oxidative stress damage in crayfish following V. parahaemolyticus infection, providing valuable insights for reducing bacterial and viral diseases in aquaculture. A deeper understanding of pathogen affects the physiology and immune systems of aquatic organisms can help develop more effective prevention and control strategies, thereby improving the efficiency and sustainability of aquaculture.

Effect of Soybean, Groundnut, Crayfish Inclusion and Vitamin C-fortified Formulated Food Blends on Biochemical, Hematological, Protein Quality and Performance Indices in Weanling Albino Rats

In this study, food staples comprising of Zea mays (maize), Sorghum bicolor (guinea corn), Glycine max (soybean), Arachis hypogea (groundnut) and Procambarus clarkii (crayfish) were traditionally processed  and formulated into maize-guinea corn based weaning diets at 16% protein level. A replica of each diet was formulated with inclusion of vitamin C (50 mg/100 g diet). Fifty four 3-week old weanling albino rats (Rattus norvegicus) weighing between 36-39 g were placed into 13 groups of 4 rats per group and administered different diet groups ranging from  maize- guinea corn base diet alone, through staples-inclusive diet (singly and in combination) and their vitamin c fortified replica diets, and standard commercial infant formula (Cerelac®) diet. Animals were sacrificed on the 28th day from onset of feeding and evaluated for biochemical, hematological and biological parameters; and sensory evaluation also conducted on the diets. Results showed significant increases in serum concentrations of protein, urea, creatinine; in the levels of red blood cell (RBC), hemoglobin (Hb) and packed cell volume (PCV); in total body weight gain and organ weights and insignificant changes in white blood cell (WBC) and platelet counts in the staples-inclusive diets compared to base diet and also in the vitamin C- fortified diets compared to non-fortified diets. Incorporation of food staples enhanced the protein quality of the diets while fortification with vitamin C increased only the biological value. On the acceptability rating, only the base gruel-crayfish mix showed significantly higher taste and overall acceptability. Therefore, the inclusion of the food blends comprising of soybean, groundnut and crayfish improved the nutritive content, hematopoietic potential, protein quality, taste and overall acceptability of the maize-guinea corn based weaning diet. These were further improved by fortification of the diets with vitamin C, while crayfish played a prominent role in taste and overall acceptance of the formulated diets. Fortification also significantly bridges the gap between the formulated weaning diets and Cerelac®, a standard commercial weaning formula in Nigeria.