Enhanced Growth Rate Research Articles

Silymarin attenuates oxidative stress and pathological changes induced by salinomycin in adult male rabbits

Feed additives are used in animal husbandry to prevent diseases and enhance growth rates. Salinomycin sodium (SAL) is an approved feed additive for rabbit fattening diets, typically administered at a dosage of 20–25 mg/kg feed with a 5-day withdrawal period. However, the misuse or abuse of SAL can result in toxicity in rabbits. This study aimed to evaluate the adverse effects of SAL administration in different organs for the first time and the protective role of silymarin in rabbits. Seven groups of rabbits were randomly allocated. The control group received no additives. The second and third groups received rations with 20 mg SAL/kg and 40 mg SAL/kg, respectively. The fourth and fifth groups received the same SAL doses with silymarin at 6.5 mg/kg body weight (bw) and 13 mg/kg bw, respectively. The sixth and seventh groups were administered silymarin alone at 6.5 mg/kg bw and 13 mg/kg bw, respectively. Rabbits were euthanized and slaughtered on day 29 following the Halal method. SAL at 20 mg/kg ration caused mild to moderate pathological changes compared to the control group, while 40 mg SAL/kg ration induced severe pathological changes. However, silymarin supplementation, alone or with SAL, improved organs histology. Both silymarin doses (6.5 mg/kg bw and 13 mg/kg bw) mitigated SAL's harmful effects. In conclusion, this study highlights the potential detrimental effects of SAL toxicity on different organs in rabbits. The supplementation of silymarin reduced and prevented these hazardous effects. These findings emphasize the promising role of silymarin as a protective agent against SAL-induced toxicity in rabbits.

Plasmid-encoded phosphatase RapP enhances cell growth in non-domesticated Bacillus subtilis strains.

The trade-off between rapid growth and other important physiological traits (e.g., survival and adaptability) poses a fundamental challenge for microbes to achieve fitness maximization. Studies on Bacillus subtilis biology often use strains derived after a process of lab 'domestication' from an ancestral strain known as Marburg strain. The domestication process led to loss of a large plasmid (pBS32) encoding a phosphatase (RapP) that dephosphorylates the Spo0F protein and thus regulates biofilm formation and sporulation. Here, we show that plasmid pBS32, and more specifically rapP, enhance growth rates by preventing premature expression of the Spo0F-Spo0A-mediated adaptive response during exponential phase. This results in reallocation of proteome resources towards biosynthetic, growth-promoting pathways without compromising long-term fitness during stationary phase. Thus, RapP helps B. subtilis to constrain physiological trade-offs and economize cellular resources for fitness improvement.

Optimizing crucible geometry to improve the quality of AlN crystals by the physical vapor transport method

In the conventional crucible structure for AlN crystal growth by physical vapor transport, owing to the long molecular transport path of Al vapor and the disruption of the gas flow by the presence of a deflector, the Al vapor easily forms polycrystals in the growth domain. The result is increased internal stress in the crystals and increased difficulty in growing large-sized crystals. On this basis, with the help of finite element simulations, a novel crucible structure is designed. This crucible not only optimizes the gas transport but also increases the radial gradient of the AlN crystal surface, making the enhanced growth rate in the central region more obvious. The thermal stresses between the deflector and the crystal are also reduced. High-quality AlN crystals with an FWHM of 79 arcsec were successfully grown with this structure, verifying the accuracy of finite element simulation of the growth of AlN crystals. Our work has important guiding significance for the growth of high-quality AlN crystals.

Role of nonthermal solar wind protons in the excitation of electromagnetic proton-cyclotron instability: a kinetic theory based exact numerical investigation

Free transverse kinetic energy i.e. perpendicular temperature anisotropy of protons excite the electromagnetic ion/proton cyclotron instability which is pertained to waves associated with prevalent electromagnetic ion/proton cyclotron emissions in various natural regions of plasmas. The transverse dielectric response function of left hand circularly polarized electromagnetic proton cyclotron (EPC) instability is calculated for two models of nonthermal Cairns distributed plasmas. These models are distinguished according to the effective thermal velocities of protons. For the energetic nonthermal protons populations, nonthermality dependent effective temperature model is proposed which significantly contributes in the excitation of aforementioned plasma mode and cause an appreciable enhancement in the instability growth rate. Exact numerical solution of dispersion relation yields oscillatory real frequency and growth rate of instability. A comparative analysis is also carried out to examine the instability behavior in distinct nonthermal and thermal plasma models. Contemporary numerical investigations are highly beneficial to understand the intricate dynamics of space plasmas.

Enhancing the Growth Performance of Whiteleg Shrimp, <i>Litopenaeus vannamei</i>, by Salt-Tolerant <i>Bacillus</i> sp.

Probiotics are vital in aquaculture for maintaining water quality, boosting aquatic species' health, and enhancing growth rates. This study investigated the effects of probiotics, namely salt-tolerant Bacillus velezensis MT50 and Bacillus amyloliquefaciens MT51, on the water quality and performance of whiteleg shrimp (Litopenaeus vannamei PL) cultured in tanks. The experimental design included two bacterial treatments and one control treatment (without Bacillus), with each treatment replicated three times. The results indicated that temperature, pH, and total alkalinity varied within the ranges of 27.8 to 28.9°C, 7.81 to 7.94, and 98.5 to 114.7 mg CaCO3 L-1, respectively, and all were maintained at appropriate levels. Additionally, other parameters such as dissolved oxygen (DO), chemical oxygen demand (COD), total suspended solids (TSS), and total ammonia nitrogen (TAN) exhibited less fluctuation in the treatments supplemented with Bacillus sp. compared to the control. Furthermore, the densities of pathogenic agents (e.g., Vibrio) in tanks with the addition of MT50 and MT51 bacteria (102 and 101 CFU mL-1, respectively) were significantly lower than in the control tanks (104 CFU mL-1). The survival rates of shrimp treated with MT50 (70.0 ± 5.3%) and MT51 (86.7 ± 3.1%) were significantly higher (P <0.05) compared to the control group (65.3 ± 3.1%). These findings suggest the potential application of B. velezensis MT50 and B. amyloliquefaciens MT51 as probiotics for sustainable aquaculture practices.

Structural characteristics of glycine aggregates grown under sub-Terahertz irradiation

Although crystal growth methods in which intramolecular bonds are induced by infrared irradiation have been investigated recently, there is very little reported on the use of electromagnetic waves to enhance growth rates. In this study, we have irradiated with 40 GHz sub-Terahertz waves during the solution growth of glycine and investigated the effect on crystal growth. Highly crystalline α-glycine grew with or without irradiation and aggregates were formed. The growth rate, however, was strongly affected by sub-Terahertz wave irradiation, with the growth rate from nucleation approximately doubling. Powder X-ray structure analysis showed that the unique diffraction peaks of glycine tended to partially shift to lower angles, with the (−110) plane and (011) plane spacing expanding by about 0.1 % and 0.15 %, respectively. The FTIR results in the terahertz region show a large absorption near 6 THz, suggesting that the structure contains water molecules.

Toward Understanding Mechanistic Regulation of Body Size and Growth Control in Bivalve Mollusks

ABSTRACTBivalves possess a pair of valves connected to a stretchable ligament that facilitates the opening and closing of the shell. The growth bioprocess commences when the supplemental materials secreted from the edge are added to the early‐constructed shell. Here, we endeavor to provide a glimpse into physiological responses, mechanistic control, and omics applications toward understanding this complex trait. In the first section, we review studies that have been performed to investigate the effects of food availability, temperature, salinity, contaminants, and climate change in natural ecosystems and under experimental conditions. These conditions affect some internal promotors and alter the concentration of particular neuropeptides and neurotransmitters that induce neuroendocrinal signals crucial for regulating this peculiar process. Besides, we provide a predicted concept for organs' size control and maintaining body size homeostasis via intertwining networks, including the Hippo pathway. On the other hand, we discuss the findings of studies employing genomics, transcriptomics, proteomics, and metabolomics approaches to uncover the mechanistic modulation of growth‐related traits in different bivalve species. We recommend further research to decipher organ size control and its intricate relationship with the entire body homeostasis. Future genetic dissection studies are also recommended to identify new key genes with a major effect that profoundly influences this trait, facilitating their potential editing to develop new strains with enhanced growth rates.

Evaluation of Probiotics Ability to Enhance Population Density, Growth Rate, and Neonates Production of Moina micrura in Different Environmental Parameters

Salinity, light intensity, and oxygen concentration are key environmental factors that significantly affect biological processes and the composition and dispersion of Moina biomass. Evaluating the effectiveness of probiotic enrichment in improving population density, growth rate, and neonate production can provide valuable details on the effectiveness of probiotics in enhancing the resilience and viability of Moina micrura under suboptimal circumstances. The purpose of this research project is to assess the efficacy of two probiotics, Bacillus pocheonensis strain S2 and Lysinibacillus fusiformis strain A1, in improving the population density, growth rate, and reproductive output in M. micrura across various environmental conditions. Moina micrura were treated with each probiotic at a volume of 5 x 105 CFU/ml under different levels of salinity (0, 2, 4, and 6 ppt), light intensity (800, 1,000, 1,500, and 2,000 lux), and oxygen concentration (80, 70, 60, and 50%). The results indicated that M. micrura treated with L. fusiformis A1 at 0 ppt attained the highest population density (6 ± 0.90 Ind./ml), growth rate (0.355 ± 0.030 µ), and number of offspring production (5 ± 0.75 Ind./ml). The highest point of population density (5 ± 0.07 Ind./ml), growth rate (0.381 ± 0.002 µ) and number of offspring (7 ± 0.41 Ind./ml) of M. micrura were obtained while treated with B. pocheonensis S2 at light intensity of 1,500 lux. Similarly, the highest population density (5 ± 0.60 Ind./ml), growth rate (0.365 ± 0.190 µ), and offspring production (2 ± 0.25 Ind./ml) of M. micrura were observed during enrichment with B. pocheonensis S2 at 70% oxygen concentration. Therefore, these results suggested that the optimum conditions for enriching M. micrura with B. pocheonensis S2 are salinity of 0 ppt, 70% oxygen concentration, and a light intensity level of 1,500 lux.

High aluminum removal efficiency by the two green microalgae, Scenedesmus sp., and Nannochloropsis sp., under laboratory conditions

Heavy metal contamination, such as aluminum (Al), is a significant global environmental concern. In addressing this issue, the ecologically-friendly method of phytoremediation using microalgae has been gaining attention. Our study explored the Al uptake capabilities of two green microalgae species, Scenedesmus sp. and Nannochloropsis sp., under laboratory conditions. Both species were exposed to varying Al concentrations (0.5, 1, and 2 mg L−1) to evaluate their growth and tolerance levels over two weeks. Results showed that Scenedesmus sp. not only demonstrated tolerance to Al up to 2 mg L−1 but also had an enhanced growth rate at the 2 mg L−1 concentration during the 8–14 day period. On the contrary, Nannochloropsis sp. displayed a reduced growth rate at 2 mg L−1 of Al concentration. Both species showed an Al removal efficiency of up to 98–99.7 %. The removal efficiency of two algae was abundance-independent in the present study. Our findings indicated that both microalgae species offer great potential for treating Al-contaminated water, with Scenedesmus sp. standing out for tolerance and removal efficiency, while Nannochloropsis sp. excels in absorbing Al at lower concentrations.

Nonlinear modulation of dispersive fast magnetosonic waves in an inhomogeneous rotating solar low-β magnetoplasma

Abstract We study the modulation of fast magnetosonic waves (MSWs) in rotating inhomogeneous low-β magnetoplasmas with the effects of gravitation and the Coriolis force. By employing the standard multiple-scale reductive perturbation technique (RPT), we derive a nonlinear Schrödinger (NLS) equation that governs the evolution of slowly varying MSW envelopes. The fast MSW becomes dispersive by the effects of the Coriolis force in the fluid motion, and the magnetic field and density inhomogeneity effects favor the Jeans instability in self-gravitating plasmas in a larger domain of the wave number (k, below the Jeans critical wave number, kJ) than homogeneous plasmas. The relative influence of the Jeans frequency (ωJ, associated with the gravitational force) and the angular frequency (Ω0, relating to the Coriolis force) on the Jeans carrier MSW mode and the modulational instability (MI) of the MSW envelope is studied. We show that the MSW envelope (corresponding to the unstable carrier Jeans mode with ωJ > 2Ω0 and k < kJ) is always unstable against the plane wave perturbation with no cut-offs for growth rates. In contrast, the stable Jeans mode with ωJ > 2Ω0 but k > kJ manifests either modulational stability or MI having a finite growth rate before being cut off. We find an enhancement of the MI growth rate by the influence of magnetic field or density inhomogeneity. The case with constant gravity force (other than the self-gravity) perpendicular to the magnetic field is also briefly discussed to show that the fast magnetosonic carrier mode is always unstable, giving MI of slowly varying envelopes with no cut-offs for the growth rates. Possible applications of MI in solar plasmas, such as those in the X-ray corona, are also briefly discussed.

Enhanced growth rates of N-type phosphorus-doped polycrystalline diamond via in-liquid microwave plasma CVD

Phosphorus-doped diamond (PDD) exhibits excellent properties, making it suitable for a wide range of applications, such as electronic devices and electrodes. Here, we report the first synthesis of PDD by in-liquid microwave plasma CVD (IL-MPCVD) under high-pressure and low-power conditions. A mixture of methanol (MeOH) and ethanol (EtOH) with triethyl phosphate ((C2H5)3PO4) and (P/C = 1000 ppm) was used for the PDD deposition. Samples were characterized by laser microscopy, Raman spectroscopy, and glow discharge optical emission spectroscopy. Notably, PDD was successfully produced at a growth rate of 280 μm/h, which is two orders of magnitude higher than conventional CVD methods. Additionally, cyclic voltammetry (CV) and impedance spectroscopy (EIS) were used to evaluate the electrochemical properties of PDD. As a result, we confirmed the wide potential window characteristic of conductive diamond and determined that the donor density was [P] = 3.8 × 1017cm⁻³. Therefore, it is clear that IL-MPCVD is applicable for very high growth rates in the CVD process for PDD synthesis.

Enhancing growth rate in homoepitaxial growth of β-Ga2O3 with flat surface via hydrochloric acid addition in mist CVD

Gallium oxide (Ga2O3) is a wide-bandgap oxide semiconductor, with a bandgap of ∼4.9 eV, making it a promising material for power device applications. This study focuses on the effect of hydrochloric acid addition on the growth rate in homoepitaxial growth of β-Ga2O3 using a mist chemical vapor deposition method. For homoepitaxial growth on a (001) β-Ga2O3 substrate, we introduced different concentrations of HCl into the source solution to assess its impact on the growth rate, crystal structures, and surface morphologies of the films. At a growth temperature of 900 °C, HCl addition linearly increased film thickness, enhancing the growth rate by 4.8 times with 9.09 vol. % HCl. No peaks associated with other phases were exhibited by each sample, indicating pure homoepitaxial growth. When comparing samples with similar film thicknesses, the root-mean-square (rms) roughness was enhanced by 1/7 with an increase in the HCl concentration. However, at 800 °C, an increasing solution concentration caused pronounced step bunching and elevated rms roughness, in contrast with the minimal effect observed at 900 °C. In experiments with hydrochloric acid addition at 900 °C, we observed a striped morphology, which maintained consistent rms roughness despite higher temperature.

The Effect of Adding Chitosan Nanoparticles Loaded with Sidr Leaf Extract (Ziziphus spina-christi) (CPNs SLE) in Diet on Pangasius sp. Infected Aeromonas hydrophila

One of the bacterial types that affects freshwater fish is Aeromonas hydrophila. These bacteria cause the occurrence of Motile Aeromonas Septicemia (MAS) disease. This study investigates the impact and optimal dosage of chitosan nanoparticles (CNPs) loaded with sidr leaves extract (SLE) on clinical manifestations, growth, hematological parameters, and survival rates of Pangasius sp. infected A. hydrophila. The experimental design employed a Completely Randomized Design with five treatments and three replications, utilizing 150 fish with an average length of 7-9 cm. Treatments included the addition of 10 ppm tetracycline (K+) in the diet and CNPs SLE with concentrations A (0 ppm), B (450 ppm), C (500 ppm), and D (550 ppm). The results demonstrate that incorporating CNPs SLE into the diet yields beneficial effects on infected Pangasius sp., leading to faster recovery from clinical symptoms, enhanced growth rates, and increased survival rates of up to 85%. The optimal dosage of CNPs SLE for Pangasius sp. infected A. hydrophila in the feed is determined to be 500 ppm.

Recycling Agricultural Waste to Enhance Sustainable Greenhouse Agriculture: Analyzing the Cost-Effectiveness and Agronomic Benefits of Bokashi and Biochar Byproducts as Soil Amendments in Citrus Nursery Production

Applying bokashi (Bok) at 10% volume/volume (v/v), biochar (BC) at 10% v/v, and their combination (Bok_BC) as soil amendments significantly enhances citrus nursery production, improving plant growth and soil health, alongside offering notable economic benefits. Our greenhouse experiment evaluated these treatments across two fertilizer doses, at half (700 μS/cm) and full (1400 μS/cm) electrical conductivity (EC) levels, compared to a control mix, demonstrating improved nutrient availability, water retention, growth rates, and potential for carbon sequestration. Based on the results of this experiment, a cost–benefit analysis was performed; the BC treatment yielded substantial savings, particularly in large nurseries where BC at 700 μS/cm electrical conductivity (EC) saved USD 1356.38 per day and the same treatment at 1400 μS/cm EC saved USD 1857.53. These savings stem from increased nutrient contents (N, P, and K) and improved water retention, reducing irrigation; shortened growth cycles due to enhanced growth rates were observed, indirectly suggesting reduced electricity costs for greenhouse operations. Additionally, the increased carbon content within the soil points toward long-term benefits from carbon sequestration, further contributing to the sustainability and economic viability of these practices. These findings highlight the economic advantage of incorporating Bok and BC into soil mixes, providing a cost-effective strategy for enhancing greenhouse agriculture sustainability.

Performance evaluation of Indigenous and Garole crossbred sheep (F1) under semi-intensive management system

A crossbreeding program was sought to enhance the genetic attributes of coastal sheep by mating them with Garole rams. The breeding program involved a combination of two male Garole with a group of twenty indigenous ewes. These sheep were permitted to mate naturally, without external intervention. Data collection focused on key metrics like birth weight (kg lamb-1), litter size, sex of lambs, instances of dystocia, weaning weight (kg lamb-1), weaning age (days), body weight (kg), age at puberty (days), and mortality rates (%). Crossbred male lambs had an average birth weight of 1.48±0.12 kg, while female lambs averaged 1.57±0.10 kg. Male to female ratio among crossbred lambs was 54.1% to 45.9%. As for weaning, males and females averaged 151.92±2.24 days and 144.00±4.20 days, respectively, with respective weaning weights of 7.98±0.85 kg for males and 8.31±0.90 kg for females. Between 30 and 60 days, male and female lambs gained at 50.16±5.94 g day-1 and 51.44±7.82 g day-1, respectively. Between 331 and 360 days, growth rates were 15.33±3.84 g day-1 and 22.33±6.00 g day-1 for males and females respectively. Dystocia, or difficult births, occurred in 75% of cases. There was no mortality for male lambs, but female lambs experienced a 20% mortality rate. Crossbreeding has emerged as a viable strategy for increasing meat production due to enhanced growth rates and their adaptability to certain environments. It can be concluded that crossbreeding of indigenous coastal sheep with Garole ram can be carried out to increase body weight and ADG. Bangladesh Journal of Animal Science 53 (2): 55-67, 2024

Dietary Chitosan Attenuates High-Fat Diet-Induced Oxidative Stress, Apoptosis, and Inflammation in Nile Tilapia (Oreochromis niloticus) through Regulation of Nrf2/Kaep1 and Bcl-2/Bax Pathways.

Fatty liver injury is a prevalent condition in most farmed fish, yet the molecular mechanisms underpinning this pathology remain largely elusive. A comprehensive feeding trial spanning eight weeks was conducted to discern the potential of dietary chitosan in mitigating the deleterious effects of a high-fat diet (HFD) while concurrently exploring the underlying mechanism. Growth performance, haemato-biochemical capacity, antioxidant capacity, apoptotic/anti-apoptotic gene expression, inflammatory gene expression, and histopathological changes in the liver, kidney, and intestine were meticulously assessed in Nile tilapia. Six experimental diets were formulated with varying concentrations of chitosan. The first three groups were administered a diet comprising 6% fat with chitosan concentrations of 0%, 5%, and 10% and were designated as F6Ch0, F6Ch5, and F6Ch10, respectively. Conversely, the fourth, fifth, and sixth groups were fed a diet containing 12% fat with chitosan concentrations of 0%, 5%, and 10%, respectively, for 60 days and were termed F12Ch0, F12Ch5, and F12Ch10. The results showed that fish fed an HFD demonstrated enhanced growth rates and a significant accumulation of fat in the perivisceral tissue, accompanied by markedly elevated serum hepatic injury biomarkers and serum lipid levels, along with upregulation of pro-apoptotic and inflammatory markers. In stark contrast, the expression levels of nrf2, sod, gpx, and bcl-2 were notably decreased when compared with the control normal fat group. These observations were accompanied by marked diffuse hepatic steatosis, diffuse tubular damage, and shortened intestinal villi. Intriguingly, chitosan supplementation effectively mitigated the aforementioned findings and alleviated intestinal injury by upregulating the expression of tight junction-related genes. It could be concluded that dietary chitosan alleviates the adverse impacts of an HFD on the liver, kidney, and intestine by modulating the impaired antioxidant defense system, inflammation, and apoptosis through the variation in nrf2 and cox2 signaling pathways.

Transcriptome analysis reveals the molecular mechanism of differences in growth between photoautotrophy and heterotrophy in Chlamydomonas reinhardtii.

The green alga Chlamydomonas reinhardtii can grow photoautotrophically utilizing light and CO2, and heterotrophically utilizing acetate. The physiological and biochemical responses of autotrophy and heterotrophy are different in C. reinhardtii. However, there is no complete understanding of the molecular physiology between autotrophy and heterotrophy. Therefore, we performed biochemical, molecular and transcriptome analysis of C. reinhardtii between autotrophy and heterotrophy. The cell growth characterization demonstrated that heterotrophic cell had enhanced growth rates, and autotrophic cell accumulated more chlorophyll. The transcriptome data showed that a total of 2,970 differentially expressed genes (DEGs) were identified from photoautotrophy 12h (P12h) to heterotrophy 12h (H12h). The DEGs were involved in photosynthesis, the tricarboxylic acid cycle (TCA), pyruvate and oxidative phosphorylation metabolisms. Moreover, the results of qRT-PCR revealed that the relative expression levels of malate dehydrogenase (MDH), succinate dehydrogenase (SDH), ATP synthase (ATPase), and starch synthase (SSS) were increased significantly from P12h and H12h. The protein activity of NAD-malate dehydrogenase (NAD-MDH) and succinate dehydrogenase (SDH) were significantly higher in the H12h group. The above results indicated that the high growth rate observed in heterotrophic cell may be the effects of environmental or genetic regulation of photosynthesis. Therefore, the identification of novel candidate genes in heterotrophy will contribute to the development of microalga strains with higher growth capacity and better performance for biomass production.

Improving duckling hatchability and quality by optimization of egg turning angle during incubation

Egg turning in incubation is crucial to the development of embryos and hatching performance. We aimed to develop a high performance duck egg incubation technique by enlarging and changing egg turning angles. Increasing turning angle from 45 to 75° did not affect the embryo early mortality during the first 15 d of incubation, which ranged from 3.5 to 4.0%, but accelerated chorioallantoic membrane (CAM) development by 17 h, and significantly (P < 0.01) reduced the late mortality from 9.4 ± 0.98% to 5.31 ± 0.63%. As the result, fertile egg hatchability increased from 91.03 ± 0.97% to 94.64 ± 0.61% (P < 0.05), so was healthy duckling rate from 87.24 ± 1.17% to 92.08 ± 0.55% (P < 0.05), and duckling live weight from 60.74 ± 0.63 g to 63.15 ± 0.35 g (P < 0.05). Changing turning angle from 75°to 60°during incubation d 15 to 25 further reduced late embryo mortality to 3.88 ± 0.47 and increased hatchability to 96.58 ± 0.68%. This changing angle turning hatched ducklings exhibited the highest growth performance during rearing than those hatched by 45 and 75° egg turning. The enhanced growth rate was paralleled by upregulations of somatotropic axis genes mRNA expression levels of the hypothalamus GHRH, liver GHR and IGF-1 during embryo incubation and duckling rearing. In conclusion, a changing angle egg turning incubation technique, 75°in the first 15 d and 60°thereafter, can enhance CAM development, upregulate somatotropic axis genes expressions, and can maximally improve embryo livability, duckling hatchability and growth performance.

Effects of the Three Gorges Dam on the mandarin fish larvae (Siniperca chuatsi) in the middle reach of the Yangtze River: Spatial gradients in abundance, feeding, growth, and survival

AbstractLarge dams significantly impact river ecosystems by disrupting connectivity, altering physicochemical variables, and modifying flow regimes. These modifications influence the spatial and temporal dynamics of biological processes and species distributions. While much research has focused on potamodromous species, there remains a gap in understanding the recovery gradients of resident species in dam‐altered rivers. This study examines the responses of larvae of a resident species, the mandarin fish (Siniperca chuatsi), to environmental alterations caused by the Three Gorges Dam (TGD) in the middle reach of the Yangtze River. We hypothesized that larval abundance, feeding, growth, and survival would exhibit longitudinal recovery gradients, improving with the increased distance from the TGD. Our results confirm this hypothesis, showing that larvae further from the TGD exhibited higher abundance, increased feeding intensity, enhanced growth rates, improved survival rate, and earlier peak abundance and hatching dates. Key environmental factors, including water temperature and discharge, increased downstream, while transparency decreased. Major tributary inputs significantly contributed to these recovery gradients. The observed longitudinal gradients in larval attributes mirrored environmental changes, underscoring the TGD impact on population recruitment. These results highlight the broader implications of dam‐induced changes on resident species recruitment, potentially affecting entire fish communities. Our study contributes to understanding the distinct spatial patterns of population trends, providing valuable insights for designing more effective conservation and management practices for resident freshwater fishes in large regulated rivers.

The Effect of Adding Chitosan Nanoparticles Loaded with Sidr Leaf Extract (Ziziphus spina-christi) (CPNs SLE) in Diet on Pangasius sp. Infected Aeromonas hydrophila

One of the bacterial types that affects freshwater fish is Aeromonas hydrophila. These bacteria cause the occurrence of Motile Aeromonas Septicemia (MAS) disease. This study investigates the impact and optimal dosage of chitosan nanoparticles (CNPs) loaded with sidr leaves extract (SLE) on clinical manifestations, growth, hematological parameters, and survival rates of Pangasius sp. infected A. hydrophila. The experimental design employed a Completely Randomized Design with five treatments and three replications, utilizing 150 fish with an average length of 7-9 cm. Treatments included the addition of 10 ppm tetracycline (K+) in the diet and CNPs SLE with concentrations A (0 ppm), B (450 ppm), C (500 ppm), and D (550 ppm). The results demonstrate that incorporating CNPs SLE into the diet yields beneficial effects on infected Pangasius sp., leading to faster recovery from clinical symptoms, enhanced growth rates, and increased survival rates of up to 85%. The optimal dosage of CNPs SLE for Pangasius sp. infected A. hydrophila in the feed is determined to be 500 ppm.