Hepatosomatic Index Research Articles

Effects of Dietary Ursolic Acid on Growth Performance and Intestinal Health of Largemouth Bass (Micropterus salmoides).

This study aimed to investigate the effects of ursolic acid (UA) on the growth performance and intestinal health of largemouth bass (Micropterus salmoides). Four diets were formulated with UA supplementation at 0, 250, 500, and 1000 mg/kg, defined as the control (CON), UA250, UA500, and UA1000, respectively. After an 8-week feeding experiment, the results showed that, in the UA500 group, the final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) increased, and the feed conversion ratio (FCR) and hepatosomatic index decreased. Total superoxide dismutase (T-SOD) activity exhibited a significant increase, and malondialdehyde (MDA) content decreased. An intestinal histological analysis revealed an improvement in the intestinal structural integrity of the UA500 group. The mRNA relative expression levels of physical barrier-related genes [occludin, claudin-1, and zonula occluden-1 (zo-1)] were upregulated. The mRNA relative expression of interlenkin 10 (il-10) increased, and the mRNA relative expression of interlenkin 1β (il-1β) and tumor necrosis factor-α (tnf-α) significantly decreased. The abundance of Firmicutes and Proteobacteria decreased, and the abundance of Tenericutes increased. The abundance of Mycoplasma, Cyanobium, and Staphylococcus decreased, while the abundance of Clostridium increased. In conclusion, dietary supplementation of UA significantly enhanced the growth performance and antioxidant capacity of largemouth bass while improving intestinal barrier function through its influence on the abundance of intestinal flora, such as Tenericutes, Firmicutes, and Mycoplasma. Optimal dietary UA levels for largemouth bass were determined to be between 498 and 520 mg/kg based on quadratic regression analyses of WGR, SGR, and FCR or T-SOD and MDA content.

Diet, feeding, and niche overlap of west coast steenbras (Lithognathus aureti) and silver kob (Argyrosomus inodorus) in the northern Benguela.

In this study, we described and compared the diet, monthly feeding intensity, and condition of west coast steenbras (Lithognathus aureti) and silver kob (Argyrosomus inodorus) caught at a unique habitat in the northern Benguela. Stomach contents of 179 west coast steenbras and 114 silver kob caught from October 2020 to September 2022 were investigated. The peak in feeding intensity of west coast steenbras appeared to be opportunistic during winter and summer periods depending on food availability. The fish condition, however, peaked at the beginning (October) and at the end (April) of the austral summer spawning period, with the hepatosomatic index (HSI) at 1.5% and the condition factor (CF) at 0.022%. Seven prey taxa were found in the diet of west coast steenbras (bivalves, bony fishes, other mollusks, algae, crustaceans, cnidaria, and polychaetas) and six taxa in the diet of silver kob (bivalves, crustaceans, bony fishes, algae, starfish, and zooplankton), indicating generalist feeding behavior in both the species. The bivalves were the most important prey items in the diet of west coast steenbras (95.9% index of relative importance [IRI]). The most important prey items in the diet of silver kob were crustaceans (83.1% IRI) and bony fishes (16.0% IRI). Crustaceans were most important in the diet of small-to-medium-sized silver kob, whereas bony fishes were most important in the diet of larger silver kob(>75 cm), with significant differences of IRI% by size class. Schoener's index of niche overlap indicated a relatively low overall niche overlap (0.11) between west coast steenbras and silver kob. This allows them to coexist as their feeding habits allow them to occupy unique niches in the coastal reef and sandy habitat and reduce competition for resources.

Attenuation of chromium (VI) and arsenic (III)-induced oxidative stress and hepatic apoptosis by phloretin, biochanin-A, and coenzyme Q10 via activation of SIRT1/Nrf2/HO-1/NQO1 signaling.

Heavy metal contamination is an alarming concern on a global scale, as drinking tainted water significantly increases human susceptibility to heavy metals. In a realistic scenario, humans are often exposed to a combination of harmful chemicals rather than a single toxicant. Phloretin (PHL), biochanin-A (BCA), and coenzyme Q10 (CoQ10) are bioactive compounds owning plentiful pharmacological properties. Henceforth, the current research explored the putative energizing effects of selected nutraceuticals in combined chromium (Cr) and arsenic (As) intoxicated Swiss albino mice. Potassium dichromate (75 ppm) and sodium meta-arsenite (100 ppm) were given in the drinking water to induce hepatotoxicity, conjugated with PHL and BCA (50 mg/kg each), and CoQ10 (10 mg/kg) intraperitoneally for 2 weeks. After the statistical evaluation, it was observed that the hepato-somatic index, metal load, and antioxidant activity (lipid peroxidation and protein carbonyl content) increased along with the concomitant decrease in the antioxidants (catalase, glutathione-S-transferase, superoxide dismutase, reduced glutathione, and total thiol) in the Cr and As intoxicated mice. Additionally, light microscopy observations, DNA breakages, decreased silent information regulator 1 (SIRT1), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase (HO-1), and NAD(P)H quinone dehydrogenase 1 (NQO1) gene expressions, together with stimulated apoptotic cell death manifested by the increased expressions of caspase 8 and caspase 3, thus, proved consistency with the aforementioned outcomes. Importantly, the treatment with nutraceuticals not only restored the antioxidant activity but also favorably altered the expressions of SIRT1, Nrf2, HO-1, and NQO1 signaling and apoptosis markers. These findings highlight the crucial role of the PHL, BCA, and CoQ10 combination in reducing Cr and As-induced hepatotoxicity in mice. By averting the triggered apoptosis in conjunction with oxidative stress, this combination increases the SIRT1, Nrf2, HO-1, and NQO1 signaling, thereby reassuringly maintaining the cellular equilibrium.

Lactiplantibacillus plantarum I Induces Gonad Growth in the Queen Scallop Aequipecten opercularis (Linnaeus, 1758) under Conditions of Climate Change

Climate change has presented a serious problem in recent times, which is why a new approach is being sought in terms of aquacultural food quality. In this study, the influence of temperature increase (by 2 °C) and pH decrease (by 0.2) was investigated on the queen scallop, Aequipecten opercularis (Linnaeus, 1758). Furthermore, the effect of a food-enriched diet with the probiotic culture Lactiplantibacillus plantarum I was assessed in climate-changed conditions. Scallops’ morphometric parameters were measured before the experimental setup and after one month of being kept in controlled conditions. Morphometric parameters included the elongation index, compactness index, convexity index, density index, condition index, meat yield, gonadosomatic index, adductor muscle index, and hepatosomatic index. Climate-changed conditions had no effect on the scallop condition index, meat yield, or hepatosomatic index. Nevertheless, the addition of probiotics to their diet had a positive effect on the queen scallops cultivated under conditions of climate change, influencing positive allometry and the increase of the gonadosomatic indices. On the other hand, the same conditions negatively affected the adductor muscle index of the scallops. To conclude, in the context of climate change conditions, queen scallops could be a good organism of choice that can be very well adapted to the changed environmental conditions, especially with the addition of the lactic acid bacteria culture Lpb. plantarum I.

Negligible additive effect of environmental concentrations of fragmented polyethylene terephthalate microplastics on the growth and reproductive performance of Java medaka exposed to 17β-estradiol and bisphenol A

To investigate whether environmental concentrations of fragmented polyethylene terephthalate (PET) microplastics (MPs) have additional or combined effects on endocrine-disrupting activity, Java medaka (Oryzias javanicus) were exposed to 17β-estradiol (E2; 5, 10, 50, and 100 ng L−1), bisphenol A (BPA; 5, 10, 50, and 100 µg L−1), and E2 and BPA combined with PET MPs (1 and 100 particles L−1) for 200 days. The growth parameters, such as body length and weight, were significantly decreased by the highest concentrations of E2 and BPA. A significant reduction in egg production was observed in female fish exposed to BPA, with an additive toxic effect of PET MPs. A female-biased sex ratio was observed in fish exposed to both chemicals. Exposure to E2 significantly increased the hepatosomatic index (HSI) in both sexes, while no significant effect was observed in the gonadosomatic index (GSI). Exposure to BPA significantly increased the HSI in female fish and decreased the GSI in both sexes of fish. An additive effect of PET MPs was observed on the GSI value of female exposed to BPA. Significant elevations in vitellogenin (VTG) levels were observed in both sexes due to exposure to E2 and BPA. Additive effects of PET MPs were observed on VTG levels in males exposed to E2 and BPA. Taken together, even long-term treatment with PET MPs induced only a negligible additive effect on the endocrine-disrupting activity in Java medaka at environmentally relevant concentrations.

Changes in the physiology and chitin metabolism in cultured juvenile Panulirus ornatus across the moult cycle

Crustaceans undergo periodic moulting events to facilitate growth, this is a physiological and energetically demanding process. In an aquaculture environment, crustaceans are generally cultured in a defined space and often at high densities, where exposure to cannibalism may be greater than in the wild. Panulirus ornatus is one such emerging aquaculture candidates, moulting frequently as juveniles and providing the opportunity to investigate the relationship between physiology and genetics throughout this important developmental period. In this study, P. ornatus juveniles were assessed every three days across the seventh to eighth juvenile moult phase, sampling was divided into six distinct time points. Brix index, hepatosomatic index, and circulating ecdysone concentrations were measured across these time points. The Brix index was validated as a useful tool for assessing the moult-stages of juvenile P. ornatus, with an increase in Brix value seen in the lead up to ecdysis. Chitin metabolism was mapped, with Chitinase 3 demonstrating hepatopancreas specificity, indicating a role outside of breakdown of dietary chitin. The investigation of physiological parameters across a moult cycle provides a basis for improving moult cycle staging in cultured P. ornatus juveniles and provides further characterisation of the changes that occur during moulting in this species.

Optimization of dietary protein based on ideal protein concept for genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water

A 60-day feeding trial was performed to optimize dietary protein based on the ideal protein concept for genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water (ISW) of 10 ppt salinity. Seven heteronitrogenous (373.6–256.5 g crude protein/kg), isocaloric (∼ 16 MJ digestible energy/kg) and isolipidic (∼ 80 g lipid/kg) semi-purified feeds were formulated and prepared with decreasing levels of crude protein (CP), namely 373.6 (CP1), 352.2 (CP2), 334.5 (CP3), 314.9 (CP4), 293.7 (CP5), 275.2 (CP6) and 256.5 g/kg (CP7). The proportion of total essential and semi-essential amino acids was kept constant in all diets as ideal amino acid profiles and total non-essential amino acids were reduced linearly to reduce the dietary CP levels. Three hundred fifteen juveniles (average weight 4.76 ± 0.01 g) were randomly assigned into seven groups in triplicate. Fish of various groups were fed thrice daily at an apparent satiation level. The growth of juveniles increased linearly and quadratically (p<0.05) when the CP level of diets was decreased from 373.6 (CP1) to 334.5 g/kg (CP3), then declined linearly. The CP2 and CP3 groups had significantly higher feed intake and lower feed conversion ratio. In contrast, low CP-fed groups had superior protein utilization, viscerosomatic index and hepatosomatic index than other groups. The CP1 and CP2 groups had significantly higher whole-body protein and lower lipid content. The whole-body non-essential amino acid content diminished linearly (p<0.05) as dietary CP levels were decreased; the whole-body essential amino acid content remained unchanged (p>0.05). The high CP-fed juveniles (CP1 and CP2) showed a significantly (p<0.05) elevated protease activity, whereas the opposite trend was noticed for amylase activity. The aminotransferase activities of the liver and muscle were reduced linearly (p<0.05) with reduced dietary CP levels. Serum glucose and cholesterol contents elevated linearly (p<0.05) with decreased dietary CP levels. Whereas, the hemoglobin content and RBC count decreased (p<0.05) in the high CP-fed juveniles. The second-order polynomial regression analysis revealed that the optimal dietary CP levels could range from 311.1 to 318.0 g/kg for GIFT juveniles reared in ISW of 10 ppt salinity. Furthermore, by adopting the ideal protein concept, the CP levels in the diet of GIFT juveniles could be reduced from 373.6 to 311.1 g/kg without affecting growth performance. The outcome of this study will assist in developing a low-protein feed with balanced essential amino acids for GIFT culture in ISW.

Liver response to the consumption of fried sunflower oil

Sunflower oil is one of the most commonly used fat sources in Argentina, and deep-fat frying is the popular food preparation process. The liver response of feeding a diet containing fried sunflower oil (SFOx) on growing rats was studied. Thirty-nine male weanling Wistar rats were randomly assigned to one of three diets for 8 wks: control (C), sunflower oil (SFO), and a diet containing SFOx, both of the sunflower diets were mixed with a commercial rat chow at weight ratio of 13% (w/w). Body weight and food consumption were recorded weekly. At t=8 wk, lipid profile and glycemia were measured. Visceral adiposity was registered. Liver was weighed and preserved for histological analysis, relative fatty acid profile, fibrosis markers and oxidative status.The three diets did not alter body weights; however, the SFOx fed rats showed increased energy intake and visceral fat; therefore, in liver saturated fat content, trans fatty acids, plus other unidentified minor components, such as hydroperoxides, hydroxides, epidioxides, hydroperoxy epidioxides, hydroxylepidioxides, and epoxides, were detected. The hepatosomatic index of SFOx rats was altered and showed hepatic steatosis. SFOx rats exhibited increased liver dichlorodihydrofluorescein-diacetate and thiobarbituric acid substance levels and oxidized-proteins content. Their livers had lower relative levels of monounsaturated, polyunsaturated fatty acids and catalase activity, but matrix metalloproteinase-9 activity was unchanged.Consumption of a diet rich in fried oil during growth could induce liver damage due to steatosis, excessive lipid toxicity and the accumulation of reactive oxygen species. Further progression could lead to hepatic fibrosis.

Effects of dietary supplementation of spray dried hog plum (Spondias pinnata (L.f.) Kurz) fruit powder on growth, digestive enzyme activity, and skin mucus immune parameters of climbing perch (Anabas testudineus (Bloch, 1972)

The effects of dietary supplementation of spray-dried hog plum (Spondias pinnata (L.f.) Kurz) fruit powder (SPP) on growth, digestive enzyme activity, and skin mucus immune parameters of climbing perch (Anabas testudineus (Bloch, 1972)) were examined. The fish (N = 330; 2.00±0.1 g) were assigned to five groups in triplicates. They were fed different SPP levels at 0, 5, 10, 15, and 20 g/kg diet for eight weeks. Flavonoids, terpenoids, phenolic compounds, tannins, steroids, glycosides, and glycosides were detected in SPP. The SPP containing diet significantly improved growth parameters (P &lt; 0.05) without a negative effect on the survival rate (P &gt; 0.05). Intestinosomatic and hepatosomatic indices significantly declined in the fish fed SPP added diets (P &lt; 0.05). There were significant elevations in digestive enzyme activities, amylase, protease, lipase, trypsin, pepsin, and esterase, in the tested fish compared to the control fish (P &lt; 0.05). Additionally, fish fed SPP containing diets showed a significant enhancement of total protein, immunoglobulin M, lysozyme, antiprotease, alkaline phosphatase, and esterase in the skin mucus compared to the control group (P &lt; 0.05). Significantly higher levels of superoxide dismutase, catalase, and total antioxidant capacity were detected in fish fed SPP containing diets compared to the control (P &lt; 0.05). These findings suggest that dietary SPP supplementation can effectively enhance fish growth, digestive enzyme activities, and mucosal immune parameters in the climbing perch. The suitable level of SPP observed in this present study was 13.00 – 15.88 g/kg diet.

Zootechnical parameters and hepatosomatic index of two genetic strains of Nile tilapia fed with β-Glucan + Mannan oligosaccharide (βG+MOS)

The increasing expansion and the rising demand for food require a greater intensification in the production of Nile tilapia (Oreochromis niloticus), and genetic improvement programs are essential to achieve this goal. In managing these programs, new genetic material is introduced after several generations of selections to reduce inbreeding and enhance genetic diversity. In this sense, analyzing the zootechnical parameters of these introductions, with an emphasis on the use of nutritional additives, is of great importance for understanding their impact on breeding programs. Thus, the aim of this study was to evaluate the zootechnical parameters and hepatosomatic index of two genetic strains of Nile tilapia from the genetic improvement program fed with β-Glucan + Mannan oligosaccharide (βG+MOS). This study utilized a 2 × 2 factorial design containing two genetic groups and two treatments with βG+MOS (Control, 0.2%). The groups were formed from the 12th generation of the Tilamax genetic improvement program (TILAMAX) and by crossing Tilamax with an introduced test strain (CBTILAMAX). In total, 96 tilapias (31.1 ± 5.73 g) were distributed into 16 aquariums, with 6 fish per aquarium, 24 per group, and four repetitions. The experimental period lasted for 41 days, and the water parameters were measured daily and maintained under ideal conditions. The condition factor and hepatosomatic index were analyzed. Final weight, total length, and standard length were measured, and other zootechnical parameters were calculated based on these data. The condition factor showed that the fish in both groups exhibited adequate health and growth during the experiment, with no differences in strain or use of additives. Similarly, the hepatosomatic index did not differ between the groups, indicating that liver size was proportional to fish body size. Similarly, no significant differences (P&gt;0.05) were observed for the other zootechnical parameters evaluated (initial and final total and standard lengths, final weight, total weight gain, condition factor using total and standard lengths, and specific growth rate). Based on these results, it is concluded that there were no differences between TILAMAX and CBTILAMAX related to performance and health under the effect of feeding with βG+MOS. This result is positive regarding the introduction of the test strain into the Tilamax genetic improvement program and establishes a starting point for further research that may provide greater clarity on its future effects.

Effect of dietary supplementation of selenium-L-methionine on growth, antioxidant capacity and resistance to nitrite stress of spotted seabass (Lateolabrax maculatus) under two rearing water temperatures

A 10-week feeding trial, followed by 24-h nitrite stress, was performed to evaluate the effects of dietary selenium-L-methionine (Se-Met) on growth, Se accumulation, antioxidant capacity, transcripts of selenoproteins and histological changes of muscle as well as resistance to nitrite stress in spotted seabass (Lateolabrax maculatus) reared at optimal (27 °C) and high (33 °C) temperatures. Five experimental diets were formulated to contain 0, 0.9, 1.8, 3.5, and 7.0 mg Se-Met/kg. Each diet was fed to fish (2.60 ± 0.2 g) in two parallel treatments at 27 or 33 °C. The results showed that elevated temperature (33 °C) induced thermal stress in fish, and fish under thermal stress exhibited lower weight gain (WG) and hepatosomatic index (HSI) but a higher condition factor (CF) compared to those reared at 27 °C. However, the growth and feed utilisation were promoted in L. maculatus with 0.9 to 3.5 mg/kg Se-Met treatments. The protein and lipid content in the muscle increased with the dietary Se-Met level, and the total Se level in the whole body and muscle showed a linear increase with dietary Se-Met supplementation. Thermal stress changed the histology of the muscle, leading to raised levels of malondialdehyde (MDA), reduced antioxidant parameters in the serum and liver, and a decrease in the transcripts of selenoprotein genes in the muscle. Meanwhile, increased antioxidant capacity of serum and liver and up-regulated transcripts of selenoprotein of muscle were observed in L. maculatus reaching a maximum with 3.5 mg Se-Met/kg treatment. After 24 h of nitrite stress, thermal stress exacerbated oxidative damage caused by nitrite stress in L. maculatus. In contrast, dietary Se-Met enhanced the resistance to nitrite stress of L. maculatus fed with Se-Met enriched diets containing 0.9 to 1.8 mg Se-Met/kg. Based on the effects of dietary Se-Met on the growth, antioxidant capacity and resistance to nitrite stress of L. maculatus, this study suggests that the optimal range of Se-Met supplementation in L. maculatus diets is 1.80 to 2.39 mg Se-Met/kg of diet at 27 °C and 1.80 to 4.46 mg Se-Met/kg of diet at 33 °C.

Effects of Dietary Melatonin on Antioxidant Capacity, Immune Defense, and Intestinal Microbiota in Red Swamp Crayfish (Procambarus clarkii).

The aim of this study was to investigate the effects of melatonin (MT) feed supplementation on the antioxidant capacity, immune defense, and intestinal flora in Procambarus clarkii (P. clarkii). Six groups of P. clarkii were fed test feeds containing different levels of MT: 0mg/kg (control), 22.5, 41.2, 82.7, 165.1, and 329.2mg/kg for a duration of 2months. The specific growth rate, hepatosomatic index, and condition factor were recorded highest in the test group of shrimp fed an MT concentration of 165.1mg/kg. Compared to the control group, the rate of apoptosis was lower in hepatopancreas cells of P. clarkii supplemented with high concentrations of MT. Analyses of antioxidant capacity and immune-response-related enzymes in the hepatopancreas indicated that dietary supplementation of MT significantly augmented both the antioxidant system and immune responses. Dietary MT supplementation significantly increased the expression levels of antioxidant-immunity-related genes and decreased the expression levels of genes linked to apoptosis. Dietary MT was associated with an elevation in the abundance of the Firmicutes and a reduction in the abundance of the Proteobacteria in the intestines; besides, resulting in an increase in the abundance of beneficial bacteria, such as Lactobacilli. The broken-line model indicated that the suitable MT concentration was 154.09-157.09mg/kg. MT supplementation enhanced the growth performance of P. clarkii, exerting a positive influence on the intestinal microbiota, and bolstered both immune response and disease resistance. Thus, this study offered novel perspectives regarding the application of dietary MT supplementation within the aquaculture field.

Replacing soybean meal with fermented rapeseed meal in diets: potential effects on growth performance, antioxidant capacity, and liver and intestinal health of juvenile tilapia (Oreochromis niloticus).

This study aims to evaluate the effects of substituting soybean meal with fermented rapeseed meal (FRM) on growth, antioxidant capacity, and liver and intestinal health of the genetically improved farmed tilapia (GIFT, Oreochromis niloticus). A total of 450 tilapia (7.22 ± 0.15g) were fed with five experimental diets, including a basal diet containing 40% soybean meal (CP0), which was subsequently replaced by 25% (CP25), 50% (CP50), 75% (CP75), and 100% (CP100) FRM in a recirculated aquiculture system for 9weeks (30 fish per tank in triplicates). The results showed that the weight gain, specific growth rate, feed intake, feed efficiency, hepatosomatic index, and viscerosomatic index of fish in both CP75 and CP100 groups were significantly lower than those in CP0 group (P < 0.05). The fish in CP100 group had the lower content of muscle crude protein while the higher level of muscle crude lipid (P < 0.05). Activities of serum aspartate aminotransferase, alanine aminotransferase along with total triglyceride in CP100 group were significantly higher than those in CP0 group (P < 0.05). There were no significant differences in the contents of liver protease, amylase, and lipase among five groups (P > 0.05). The activities of liver total antioxidant capacity and superoxide dismutase exhibited the increased tendency with the increase of FRM replacement levels from 25 to 50% (P < 0.05), while then significantly decreased from 75 to 100% (P < 0.05). Histological morphology indicated that the fish in between CP75 and CP100 groups had poor liver and intestine health. Intestinal microbial diversity analysis showed that the relative abundance of Cetobacterium and Alcaligenaceae in both CP75 and CP100 groups were lower than that in other three groups. In conclusion, the maximum replacement level of soybean meal with FRM in the diet was determined to be 50% without compromising the growth performance, antioxidant status, and liver and intestinal health of tilapia under the current experimental conditions. The observed decrease in food intake and subsequent retarded growth performance in the CP75 and CP100 groups can be attributed directly to a reduction in feed palatability caused by FRM.

Protein-sparing effects of lipids in the diet of golden pompano (Trachinotus ovatus): evaluation of growth, feed utilization, and lipid metabolism.

To investigate the influences of dietary protein and lipid levels on the growth, feed utilization, morphometric parameters, body composition, serum biochemical parameters, and lipid metabolism of golden pompano (Trachinotus ovatus), nine test diets containing three protein levels (35%, 40%, and 45%) and three lipid levels (8%, 13%, and 18%) were designed in the present study. Each diet (named D1-D9) was randomly assigned to feed triplicate groups of golden pompano juvenile (initial weight ~ 70 g) for 50 days. The results showed that the dietary lipid levels positively correlated with weight gain, specific growth rate, and protein efficiency ratio (PER), suggesting that the high lipid diets (18%) can be efficiently utilized in this fish species. The dietary protein levels have no significant influences on the growth and feed utilization except for the PER. Increasing dietary protein levels resulted in a decrease in hepatosomatic index (HSI), viscerosomatic index (VSI), and intestinal somatic index (ISI), while the dietary lipid level did not have a significant impact on morphological indices except for ISI. The dietary protein and lipid levels had no significant influences on the contents of crude lipid, crude ash, and moisture of whole body, while the crude protein contents was significantly affected by the dietary protein levels. Serum biochemical indexes, including cholesterol (CHO), triglycerides (TG), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL), as well as HDL/LDL ratio were significantly affected by the dietary lipid levels, but not by the dietary protein levels. The expression levels of genes and their associated proteins involved in hepatic lipogenesis (Srebp-1c and Fas) and fatty acids β-oxidation (Pparα and Cpt-1) were up-regulated with increasing dietary lipid levels, while the former was up-regulated, and the latter was down-regulated with increasing dietary protein levels. Considering the present results in terms of growth performance, feed utilization, morphometric parameters, and lipid metabolism, the recommended dietary protein and lipid levels for golden pompano are 40% and 18%, respectively. The findings suggested that this species exhibits a significant protein-sparing effect on lipid utilization.

Poly-β-hydroxybutyrate supplementation enhanced the growth and immune responses of juvenile Nile tilapia (Oreochromis niloticus)

Development of alternative disease treatment and prevention strategies has received considerable attention in recent years due to frequent epizootic outbreaks in modern intensive aquaculture. Poly-β-hydroxybutyrate (PHB) is a biopolymer synthesized by some bacteria with potential immunostimulatory effects. This study analyzed the potential of PHB as an immunomodulator in juvenile Nile tilapia utilizing in vitro and in vivo approaches. Head-kidney-derived macrophage production of intra- and extra-cellular superoxide anion exhibited significant linear and quadratic relationships with graded doses (0.0, 0.5, 1.0, 2.0, 4.0 and 8.0 mM) of a PHB precursor, 3-hydroxybutryate (3HB). Additionally, lyophilized PHB-synthesizing bacteria, Zobellella denitrificans (ZD1), were supplemented to a practical basal diet for Nile tilapia (36% crude protein and 6% crude lipid) to produce five isonitrogenous and isolipidic experimental diets containing PHB in five stepwise increments (0.125, 0.25, 0.5, 1.0, and 2.0% of dry-diet weight). After termination of the feeding trial, Nile tilapia exhibited dose-dependent linear and quadratic relationships in percentage weight gain, as well as feed efficiency, protein conversion efficiency, and hepatosomatic index. Finally, PHB-supplemented diets did significantly modulate intestinal microbiota composition. In conclusion, Nile tilapia exhibited enhanced growth parameters, condition factors, immunological responses, and intestinal microbiota modulation when fed PHB, with the optimal inclusion level determined to be 1% of dry diet.

Dietary Pediastrum boryanum microalgal extract improves growth, enhances immunity, and regulates immune-related genes in Nile tilapia

BackgroundIdentifying alternative sustainable feed sources with high nutritional values is crucial for the future of environmentally and socially responsible aquaculture. In this regard, microalgae have been proven to have positive effects on fish health, which overwhelmed our interest in this study.MethodsPediastrum boryanum (P. boryanum) was incorporated into Nile tilapia feed at concentrations of 0, 0.75, and 1.5 mg/kg, as control, PbExt0.75, and PbExt1.5 groups to assess its effects on growth and biochemical indices, oxidant/antioxidant activities, immune and stress-related gene expression, and intestinal morphology.ResultsAfter 8 weeks, fish fed P. boryanum supplemented feed exhibited significant increases in final weight, length, condition factor, body weight gain, and specific growth rate, while the spleen-somatic index (SSI) and hepatosomatic index (HSI) showed no significant differences compared to the control group. Dietary P. boryanum supplementation also enhanced IgM levels and lysozyme activity, along with no marked effect on markers of liver function enzymes (alanine aminotransferase/ALT and aspartate aminotransferase/AST) or protein status (total protein and albumin). Furthermore, P. boryanum addition increased the activity of superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) enzymes, highlighting its antioxidant potential, whereas malondialdehyde (MDA) concentrations showed no significant differences among the groups. Gene expression analysis revealed that tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and transforming growth factor-β1 (TGF-β1) expression notably increased in groups fed P. boryanum containing feed, while no significant difference was observed in hepatic Heat Shock Protein 70 (HSP70) mRNA expression. Histopathological examination revealed no adverse effects of P. boryanum supplementation on the liver, spleen, or intestinal tissues. Villous height and villous surface area were notably increased in the high P. boryanum supplementation group, suggesting improved intestinal integrity and nutrient absorption.ConclusionDietary P. boryanum supplementation can potentially improve growth performance, immune response, antioxidant status, and intestinal health of Nile tilapia, making it a promising candidate for sustainable aquaculture.

The impact of Neoporphyra haitanensis dietary supplement on astaxanthin esters and fatty acids accumulation associated with immune promotion in Pacific white shrimp (Litopenaeus vannamei)

To explore and develop effective feed additives for enhancing shrimp cultivation, an 8-week feeding experiment was conducted in Litopenaeus vannamei with dietary supplementation ranging from 0% to 5% Neoporphyra haitanensis. The results indicated that a diet containing 2% N. haitanensis enhanced trypsin activity, as well as the height and width of intestinal villi, leading to improved growth performance of L. vannamei. The specific growth rate (SGR), weight gain rate (WGR) and the ratio of flesh content were increased by 1.1 to 2.0 times, while the hepatosomatic index (HSI) and condition factor (CF) values were 85.6% and 91.5% of those in the control group, respectively. Additionally, the inclusion of 2% N. haitanensis in the diet led to a 1.1-fold increase in the accumulation of fatty acids, particularly DHA and EPA. The diet also exhibited elevated levels of β-carotene, zeaxanthin, α-cryptoxanthin, and β-cryptoxanthin, which correlated with the increased content of carotenoids in the shrimp. The exoskeleton was identified as the primary site for assimilating α−/β-carotenes, free astaxanthin, and its diesters (mainly EPA and DHA chains), accompanied by heightened redness (a*) value. Meanwhile, the muscle tended to accumulate astaxanthin and its monoesters (mainly C16:0 and C18:0 chains) and hepatopancreas had lowest contents of astaxanthin and its diesters (mainly DHA chain). Furthermore, the Toll and IMD immune signal pathways in L. vannamei were activated with 2% N. haitanensis in the die, up-regulating the expression of immune-related genes dorsal, relish and imd, and antibacterial peptides genes crustin, lysozyme, and penaeidin3a. Concurrently, the activities of immune-related enzymes ACP and AKP, as well as antioxidant enzymes CAT, SOD, and GPH-Px, were enhanced, while AST and ALT activities were decreased. In terms of intestinal health, the addition of 2% N haitanensis contributed to the preservation of the intestinal tissue structure and promoted the abundance of beneficial bacteria, while reducing the abundance of Vibrio in L. vannamei. The enhanced immune and antioxidant performance of L. vannamei was demonstrated to prevent intestinal structure damage and increase survival rates, as evidenced by WSSV infection experiments. These results offer valuable insights into the dose-dependent effects of dietary seaweeds in promoting shrimp cultivation.

Proteomics and Its Combined Analysis with Transcriptomics: Liver Fat-Lowering Effect of Taurine in High-Fat Fed Grouper (Epinephelus coioides).

In order to understand the intervention effect of taurine on liver fat deposition induced by high fat intake in the orange-spotted grouper (Epinephelus coioides), we performed proteomic analysis and association analysis with previously obtained transcriptomic data. Three isoproteic (47% crude protein) diets were designed to contain two levels of fat and were named as the 10% fat diet (10F), 15% fat diet (15F), and 15% fat with 1% taurine (15FT). The 10F diet was used as the control diet. After 8 weeks of feeding, the 15F diet exhibited comparable weight gain, feed conversion ratio, and hepatosomatic index as the 10F diet, but the former increased liver fat content vs. the latter. Feeding with the 15FT diet resulted in an improvement in weight gain and a reduction in feed conversion ratio, hepatosomatic index, and liver fat content compared with feeding the 15F diet. When comparing liver proteomic data between the 15F and 15FT groups, a total of 133 differentially expressed proteins (DEPs) were identified, of which 51 were upregulated DEPs and 82 were downregulated DEPs. Among these DEPs, cholesterol 27-hydroxylase, phosphatidate phosphatase LPIN, phosphatidylinositol phospholipase C, and 6-phosphofructo-2-kinase were further screened out and were involved in primary bile acid biosynthesis, glycerolipid metabolism, the phosphatidylinositol signaling system, and the AMPK signaling pathway as key DEPs in terms of alleviating liver fat deposition of taurine in high-fat fed fish. With the association analysis of transcriptomic and proteomic data through KEGG, three differentially expressed genes (atp1a, arf1_2, and plcd) and four DEPs (CYP27α1, LPIN, PLCD, and PTK2B) were co-enriched into five pathways related to fat metabolism including primary bile acid synthesis, bile secretion, glycerolipid metabolism, phospholipid D signaling, or/and phosphatidylinositol signaling. The results showed that dietary taurine intervention could trigger activation of bile acid biosynthesis and inhibition of triglyceride biosynthesis, thereby mediating the liver fat-lowering effects in high-fat fed orange-spotted grouper. The present study contributes some novel insight into the liver fat-lowering effects of dietary taurine in high-fat fed groupers.

Baseline study of biomarkers of exposure to metal and polycyclic aromatic hydrocarbon in wild Mugil cephalus from the coastal waters of Fiji

The indirect exposure and effects of marine pollutants such as metals and polycyclic aromatic hydrocarbons, present significant health concerns for human coastal communities that rely on fish consumption as a regular nutritional source. This study verified Mugil cephalus (“mullet”) as an adequate sentinel species for biomonitoring environmental health and conducting risk assessments using biomarkers in Fiji. A non-parametric Kruskall Wallis Test was employed at a 5 % significant difference level to test sample group differences. Sampling was performed over five months in two Fijian study areas, i.e., Laucala Bay and the Ba River Delta by local fishers based on Fiji’s wet season (Nov-Mar). The K factor and hepatosomatic index (HSI) were relatively lower in mullet from Laucala Bay compared to the Ba River Delta, with HSI having a significant difference (χ2= 3.64, d.f. = 1, p-value = 0.057). No significant differences were observed for metals (Pb and Cr) at an instrumental limit of detection of 0.05 mg kg−1, but an important finding was that the levels of Cr in edible tissues of mullet from both study sites exceeded the permissible limits for human consumption set by the World Health Organisation (0.05–0.15 mg kg−1) by approximately 2-fold in Laucala Bay and 3-fold in Ba River Delta. The levels of Hg and Cd in the two sample groups were determined to be below the instrumental limit of detection of 0.1 mg kg−1. Total biliary polycyclic aromatic hydrocarbons (PAHs) were significantly higher in mullet from the Ba River Delta (χ2 = 21.14, d.f. = 1, p-value < 0.001), particularly for phenanthrene (χ2 = 24.678, d.f. = 1, p-value < 0.001). No statistical variations were observed in phase I biotransformation (ethoxyresorufin O-deethylase); however, phase II biotransformation activity (glutathione S-transferase) was found to be significantly higher in mullet from the Ba River Delta compared to Laucala Ba (χ2 = 35.85, d.f. = 1, p-value < 0.001). Similarly, no remarkable variations were observed in glutathione peroxidase activity, but glutathione reductase activity was significantly higher in mullet (χ2 = 5.05, d.f. = 1, p-value = 0.025) from Laucala Bay compared to Ba River Delta. Considering biological damages from oxidative stress, levels of lipid peroxidation were significantly higher (χ2= 4.10, d.f. = 1, p-value = 0.043) in mullet from Ba River Delta, including higher occurrences of micronuclei (χ2= 12.66, d.f. = 1, p-value = <0.001) and other abnormal erythrocyte nuclei (χ2= 26.67, d.f. = 2, p-value < 0.001), suggesting genotoxic damage. These findings 1) support the use of mullet as a suitable reference species for future ecotoxicology studies in Fiji, 2) are essential to take informed health and safety considerations regarding mullet consumption, 3) provide a baseline to compare future monitoring results and, 4) underscore the importance of incorporating biomonitoring practices in future environmental risk assessments.

Can photoperiod improve growth performance and antioxidant responses of pacu (Piaractus mesopotamicus) reared in recirculation aquaculture systems?

The present study investigated the best photoperiod for culturing pacu (Piaractus mesopotamicus) in recirculation aquaculture systems (RAS) based on its growth performance and hematological and oxidative stress responses. Juveniles (∼ 5g) were subjected to five treatments (in triplicate): 24L (light):0D (dark), 15L: 09D, 12L:12D, 9L:15D, and 0L:24D for 45 days. A total of 225 pacu individuals were randomly distributed among 15 tanks of 210L (n = 15 per tank). Zootechnical, hematological (glucose, lactate, hematocrit, and hemoglobin), and antioxidant and oxidative stress parameters (glutathione S-transferase (GST), total antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were analyzed. The zootechnical parameters (e.g., weight gain, Fulton's condition factor, and specific growth rate) were better and worse with 9L:15D and 24L:0D photoperiods, respectively. The hepatosomatic index was higher and lower in the 0L:24D and 9L:15D photoperiods. Blood lactate levels and antioxidant and oxidative stress responses were increased in the longest photoperiods (15L:9D and 24L:0D). In contrast, the treatments that showed lower oxidative damage (liver, gills, brain, and muscle) were 9L:15D and 12L:12D. In conclusion, manipulating artificial light is one way to improve fish growth and health, where the best photoperiod for pacu farming in RAS is 9L:15D.