Dietary supplementations modulate the physiological parameters, fatty acids profile and the growth of red claw crayfish (Cherax quadricarinatus)

Bee venom enhances performance and immune function in thinlip mullet: A promising approach for sustainable aquaculture

As an environmentally friendly alternative to antibiotics, bee venom holds promise for aquaculture due to its diverse health advantages, including immune-amplifying and anti-inflammatory features. This study investigated the effects of dietary bee venom (BV) on the growth and physiological performance of Thinlip mullet (Liza ramada) with an initial body weight of 40.04 ± 0.11 g for 60 days. Fish were distributed to five dietary treatments (0, 2, 4, 6, and 8 mg BV/kg diet) with three replicates. Growth traits, gut enzyme ability (lipase, protease, amylase), intestinal and liver histology, blood biochemistry, immune responses [lysozyme activity (LYZ), bactericidal activity (BA), nitroblue tetrazolium (NBT%)], and antioxidant status [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), malondialdehyde (MDA)] were evaluated. BV supplementation significantly improved growth performance, digestive enzyme activity, histological integrity of organs, immune responses (LYZ, BA), and antioxidant status (SOD, CAT, GPx), while declining MDA levels. Optimal BV levels were identified between 4.2 and 5.8 mg/kg diet for different parameters. Overall, the findings suggest that BV supplementation can enhance growth and physiological performance in Thinlip mullet, highlighting its potential as a beneficial dietary supplement for fish health and aquaculture management.

Modulation of growth performance, feed utilization, and physiological traits in redbelly Tilapia (Tilapia zillii) through environmental and sex-based interactions

This study explored the combined influence of tank color, stocking density, and gender on Tilapia zillii's performance and well-being. In this 120-day trial, 320 T. zillii, each initially weighing 10.0 ± 0.1 g/fish, were distributed among 24 tanks. The experiment included eight distinct treatment combinations, varying tank color (blue and green), stocking density (10 and 30 fish/m3) and sex (monosexual and mixed). The results showed that blue tanks improved specific growth rate and condition factor, while green tanks were better for feed utilization. Density at 30 fish/m3 showed the highest mean values of final body weight and total length, weight gain (WG), and gain length. Mono-sex outperformed mixed-sex ones in WG and daily growth. Interactions between color, density and sex were significant, affecting growth and feed utilization. Green tanks were best for protein profiles, while blue tanks excelled in glucose. A density of 10 fish/m3 yielded the highest protein profiles, and mono-sex fish had higher protein profiles. For lipid profiles, green tanks were superior, and density affected lipid profiles. Mixed-sex populations were best for certain lipid profile parameters. Interactions between these factors also played a significant role, making the biochemical profiles of T. zillii a complex interplay of various factors. The results explored that tank color, fish density and sex influence the activity of nonspecific immune enzymes in the liver of T. zillii. Blue tanks and lower fish density led to higher nonspecific immune enzymes, while mono-sex fish exhibited more significant nonspecific immune enzymes. Complex interactions between these factors also influenced nonspecific immune enzyme activities. Blue tanks increased malondialdehyde (MDA) levels, while green tanks raised glutathione S-transferases (GST) and catalase (CAT) levels. Lower fish density led to higher MDA, while higher density increased GST and CAT. Mono-sex fish had more MDA and GST, while mixed-sex fish showed greater CAT levels. Complex interactions among these factors affected the antioxidant levels in T. zillii. In summary, our study suggests that rearing T. zillii in green tanks at higher densities (30 fish/m3) and in mono-sex conditions yields the best results in terms of growth and overall performance.

Comparative impact of replacing fish meal with azolla on growth, water quality, and physiology of red tilapia fingerlings at varying salinities

A 210-day experiment to assess the efficacy of substituting azolla plant powder at levels of 0, 20, 40, and 60% for fish meal on red tilapia fingerlings (RTF, initial weight of 18.23 ± 0.12 g) performance under salinity levels of 5, 18, and 28ppt. Among the various conditions, RTF-fed 20% azolla at 28 and 5ppt salinity showcased the highest specific growth rate (SGR), whereas the lowest SGR was observed in fish-fed 60% azolla at 5ppt salinity. Upon azolla incorporation, noteworthy elevations in phytoplankton, zooplankton, dissolved oxygen (DO), pH, NH3, and NO3 were noted and conversely, azolla introduction led to decreased NH4 and NO2 concentrations in all salinity levels. Further, a significant (p < 0.05) interaction between azolla levels and water salinity (S×A) significantly impacted the hematological parameters of RTF. The highest levels of superoxide dismutase (SOD), catalase (CAT), and total protein (TP) were found in RTF-fed 20% azolla at 28ppt salinity, while the lowest CAT and TP levels occurred in RTF-fed 60% azolla at 5ppt salinity. The highest aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were recorded in the RTF group fed 60% azolla at 5ppt salinity, with the lowest values seen in the group given 20% azolla at 28ppt salinity. RTF fed a 20% azolla diet at 18ppt salinity exhibited the highest lysozyme value, in contrast to the lowest value observed in the RTF group fed the control diet at 18ppt salinity. In conclusion, this study recommends the utilization of azolla at inclusion levels ranging from 20 to 40%, as it has the potential to notably enhance the immune system and elevate the survival rate of RTF.

Natural zeolite for heavy metal, ammonia removal, and physiological responses in European sea bass (Dicentrarchus labrax) juveniles tanks with different densities

The present study aims to investigate the influence of zeolite usage and stocking densities on various parameters, including ammonia removal from water, accumulation of heavy metals in fish organs, water quality, growth performance, feed efficiency, muscle composition, as well as hematological and biochemical parameters in European seabass (Dicentrarchus labrax) over a 90-day duration. A total of 2400 D. labrax with an initial weight of 9.83 ± 2.02 g and initial length of 9.37 ± 0.32 cm were distributed among 24 tanks. The research involved six distinct treatment groups, with two different zeolite levels (0 and 15 ppt) and three stocking density levels (50, 100, and 150 fish/m3), each replicated four times. The results of the research demonstrate a statistically significant improvement (p < 0.05) in water quality measures with the introduction of zeolite. The successful implementation of this amendment mitigated the adverse effects of fish density on water quality parameters. Higher stocking density negatively impacted European sea bass growth, feed utilization, and hemato-biochemical indicators. Zeolite use effectively alleviated these adverse effects, particularly on performance, feed utilization, hematological, and biochemical parameters. The study's results indicate that the utilization of zeolite has shown to be efficacious in mitigating the accumulation of heavy metals in both water and fish organs, while concurrently augmenting fish attributes. However, the increase in density led to a significant decrease in the accumulation of heavy metals in both water and fish organs. The present study highlights the capacity of natural zeolites to mitigate the negative consequences associated with water quality concerns. The efficiency of these zeolites in limiting the accessibility of heavy metals in polluted water is shown, hence minimizing their accumulation in fish organs. In addition, the improvement of fish performance has the capacity to have a beneficial influence on both the well-being and efficiency of fish in aquaculture. Additional research is essential to fully understand the complex molecular pathways involved in utilizing natural zeolite under different fish densities.

Evaluation of Dietary Essential Amino Acid Supplementation on Growth, Digestive Capacity, Antioxidant, and Intestine Health of the Juvenile Redclaw Crayfish, Cherax quadricarinatus

The present study was an 8-week feeding trial investigating the effects of lysine and threonine supplementation in vegetable-based diets on growth, antioxidative capacity, and gut microbiota of juvenile redclaw crayfish, Cherax quadricarinatus (initial weight 11.52 ± 0.23 g). The lysine and threonine were supplemented to formulate five isonitrogenous (37%) and isolipidic (9%) diets containing 0% (control), 0.2% lysine (L0.2), 0.2% threonine (T0.2), 0.4% lysine (L0.4), and 0.4% threonine (T0.4), respectively. Compared to the control, weight gain rate (WGR) and specific growth rate (SGR) of C. quadricarinatus significantly increased with increasing dietary lysine and threonine supplementation from 0.2% to 0.4% (P < 0.05). Hepatopancreas trypsin activity significantly increased with increasing levels of lysine and threonine in diets (P < 0.05). However, the pepsin, lipase, and amylase activities were not affected by dietary levels of lysine and threonine (P > 0.05). Compared with the control, crayfish in T0.4 and L0.4 showed significantly higher glutathione peroxidase (GPx) activity (P < 0.05), lower alanine aminotransferase (ALT) activity, and lower malondialdehyde (MDA) content (P < 0.05). Supplementation with 0.4% lysine significantly changed the composition of the gut microbiota (P < 0.05), which showed a significantly increased relative abundance of Proteobacteria and decreased Firmicutes, Actinomycetes, and Pontomyces (P < 0.05). The PICRUSt analysis demonstrated that the abundance of the metabolism and cellular processes pathways in the L0.4 group were markedly decreased compared with the control (P < 0.05). Meanwhile, a tighter interaction of the microbiota community in crayfish was observed in the T0.4 experimental group. In conclusion, these results suggested that dietary supplementation with 0.4% threonine could significantly promote growth and improve microbial health in juvenile C. quadricarinatus.

Analysis of the Differences in Muscle Nutrition among Individuals of Different Sexes in Redclaw Crayfish, Cherax quadricarinatus

Redclaw crayfish (Cherax quadricarinatus) was introduced to China many years ago. In recent years, a breeding boom for C. quadricarinatus has been set off in China due to a breakthrough in key technology of seedling breeding. The size and growth rate of C. quadricarinatus vary greatly between female and male individuals, usually the size and growth rate of male individuals are bigger than that of female individuals. There is usually a certain linkage relationship between the sex traits of crustaceans and their own nutrition. In order to explore the linkage relationship between the sex traits of C. quadricarinatus and its nutritional components, this study measured and analyzed the muscle nutritional components of female and male individuals. The results showed that the meat yield rate of male individuals was significantly higher than that of females (p < 0.05), and the crude fat content was significantly lower than that for females (p < 0.05). The ratios of essential amino acids to total amino acids for females and males were 39.61% and 38.49%, respectively. The ratios of essential amino acids to non-essential amino acids were 79.69% and 75.66%, respectively, which far exceed FAO/WHO standards and both belong to high-quality protein. The total amount of flavor amino acids of male individuals was significantly higher than that of female individuals (p < 0.05). The total amount of polyunsaturated fatty acids and the polyunsaturated fatty acid eicosapentaenoic acid of males are both significantly higher than that of females (p < 0.05). Studies have shown that there are certain differences in nutrition between male and female individuals. Compared with female individuals, the meat yield rate, crude protein content, and edible value of the muscles of male individuals is higher.

Lycopene Improves Metabolic Disorders and Liver Injury Induced by a Hight-Fat Diet in Obese Rats

Epidemiological studies have shown that the consumption of a high-fat diet (HFD) is positively related to the development of obesity. Lycopene (LYC) can potentially combat HFD-induced obesity and metabolic disorders in rats. This study aimed to investigate the effect of LYC on metabolic syndrome and assess its anti-inflammatory and antioxidant effects on the liver and adipose tissue in rats fed an HFD. Thirty-six male Wistar albino rats were divided into three groups. Group Ι (the control group) was fed a normal diet, group ΙΙ (HFD) received an HFD for 16 weeks, and group ΙΙΙ (HFD + LYC) received an HFD for 12 weeks and then LYC (25 mg/kg b.wt) was administered for four weeks. Lipid peroxidation, antioxidants, lipid profile, liver function biomarkers, and inflammatory markers were determined. The results showed that long-term consumption of an HFD significantly increased weight gain, liver weight, and cholesterol and triglyceride levels. Rats on an HFD displayed higher levels of lipid peroxidation and inflammatory markers. Moreover, liver and white adipose tissue histopathological investigations showed that LYC treatment mended the damaged tissue. Overall, LYC supplementation successfully reversed HFD-induced changes and shifts through its antioxidant and anti-inflammatory activity. Therefore, LYC displayed a therapeutic potential to manage obesity and its associated pathologies.