Background: The study has a bifold objectives, firstly to determine the concentration of iron (Fe) in the soil and pond water within the vicinity of a historical gold mine region located in the Kolar Gold fields (KGF), Karnataka, India. Secondly, the study seeks to investigate the process of bioaccumulation of the heavy metal, iron in the muscles of Zebrafish inhabiting the same area. 
 
Methods: To achieve the objectives, the study employed Thermo Scientific&rsquo;s Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and ICP-AES using Iteva software to evaluate and statistically analyze the distribution of iron in the soil, pond water and muscles samples. Four soil sample sites (A, B, C and D) were selected based on their proximity to residential area. Soil samples were examined from January to December, 2022, while pond water samples were analyzed between April and October, 2022 following a southwest monsoon rain. 
 
Result: During the study, the analysis of soil samples taken from the four mine landfills revealed elevated levels of heavy metals, with the highest mean concentration of 41915.17 mg/kg found in Site A. In the pond water, sample site B exhibited an exceedingly high Fe concentration during October with 5.56 mg/L followed by sample site D, A and C with 4.89, 3.89 and 3.54 mg/L, respectively against 0.98 mg/L in the control site. The concentration of Fe in the muscles was exceedingly high in the sample site B with 10457 mg/Kg on day 30 of October to that of 8219 mg/Kg on day 30 of April month, which is far above the threshold value of 100 mg/kg as per the regulatory bodies <a href="#who_1993">(WHO 1993)</a>. The outcome of this experiment will facilitate the assessment of surface soil contamination levels and the likelihood of contaminants entering the aquatic environment, resulting in the bioaccumulation of heavy metals in the aquatic organisms.

Spatial Evaluation of the Heavy Metal Iron in Soil, Pond Water and its Mobility into the Muscles of Zebrafish using ICP-OES

<div>Background: Periphyton-based aquaculture improves water quality, provides a natural food supplement, limits harmful bacteria, provides a safe haven for shrimp to escape, and adds living space. The impacts of diverse natural substrates on periphyton formation were examined under earthen lined pond seawater systems as a first step in analysing the sustainability of periphyton-based shrimp production. 
 
Methods: Natural substrates such as coconut coir, coconut shell and split bamboo pole were placed inside the earthen lined pond filled with seawater for duration of 45 days. Periphyton samples were obtained from each type of substrate on the 15th, 30th and 45th days of the experiment. For all substrates, periphyton biomass and chlorophyll &lsquo;a&rsquo; pigment in the periphyton were measured at depths of 0 to 40 cm, 40 to 80 cm and 80 to 120 cm. Physico-chemical parameters of experiment pond water were recorded during periphyton samplings. 
 
Result: During the experiment, coconut coir showed higher periphyton biomass in terms of dry matter (DM) (3.4995 0.31201 mg/cm2) and chlorophyll &lsquo;a&rsquo; pigment (3.2949 0. 27076 mg/cm2). Duncan&rsquo;s Multiple Range Test and One Way ANOVA of diverse data reveal a significant difference (P 0.05) between the substrates in periphyton biomass and chlorophyll &lsquo;a&rsquo; pigment. In all three substrates, a Student&rsquo;s &lsquo;t&rsquo; test analysis shows that the upper 0 to 40 cm depth yields more periphyton biomass and chlorophyll &lsquo;a&rsquo; content than the other levels. Coconut coir was the best natural substrate for periphyton growth among the three.</div>

Effect of Different Natural Substrates on Periphyton Production under Earthen Lined Seawater Pond for Periphyton based Aquaculture

Background: This study investigates bacterial contaminants and pathogenic species isolated from fish pond wastewater (FPWW) in Bechar province, Southwestern Algeria and assesses their antibiotic resistance propfile. 
 
Methods: A total of 21 FPWW samples were analyzed using different culture media to isolate bacterial contaminants via the membrane filter technique. Following purification, all bacterial isolates were identified through biochemical tests and subjected to susceptibility testing by the Kirby-Bauer disc diffusion method on Mueller-Hinton (MH) agar and the broth microdilution technique. Antimicrobial residue detection was also carried out using the microbiological tube test method (MTT). 
 
Result: We successfully isolated 68 bacterial isolates, classified into six bacterial groups: non-Enterobacteriaceae (41.18%), Enterobacteriaceae (38.24%), Streptococcaceae (8.82%), Pseudomonadaceae (7.35%), Erwiniaceae (2.94%) and Neisseriaceae (1.47%). According to the Chi-Square Goodness-of-Fit Test, this distribution was highly significant (p &lt; 0.001). The isolated species included Aeromonas hydrophila hydrophila, Streptococcus spp., Enterobacter spp., Serratia spp., Escherichia coli, Citrobacter spp., Klebsiella spp., Plesiomonas shigelloides, Kluyvera spp., Pseudomonas aeruginosa, Pantoea spp., Chromobacterium violaceum, Salmonella choleraesuis and Vibrio spp. Susceptibility testing of the bacterial contaminants revealed variable responses among the strains, with increased resistance to &beta;-lactam antibiotics. Multidrug resistance results showed that 17 strains (25%) exhibited resistance to three to six different antibiotic classes, with Multiple Antibiotic Resistance (MAR) indices ranging from 0.28 to 0.68. The variability in MAR indices among bacterial groups was statistically significant (ANOVA, p = 0.0498). Furthermore, no growth-inhibiting substances were detected in the wastewater samples using the MTT method.

Antibiotic Resistance of Pathogenic and Bacterial Contaminants Isolated from Fish Pond Wastewater in Bechar Province, Southwestern Algeria

Background: This study aimed to assess the bacteriological and physicochemical properties of the water supplying the artificial concrete fish ponds in Bechar province (Southwestern Algeria). 
&nbsp; 
Methods: Bacteriological and physicochemical parameters were assessed using standard procedures for water and wastewater analysis, as outlined by the APHA and WEF. 
&nbsp; 
Result: Physicochemical analysis showed that water temperatures ranged from 18 to 21oC, with a neutral to slightly alkaline pH (7.4 to 8.53). Electrical conductivity (EC) varied from 1313 to 3848 &micro;S/cm and the water was classified as hard, with total hardness (TH) ranging from 297 to 873 mg/L. Bacteriological analysis revealed that 13 of the 21 samples (62%) complied with national regulations, while 8 samples (38%) were contaminated with fecal coliforms, fecal streptococci and sulfite-reducing Clostridia (SRC) spores. Five samples (Sb7, Sb8, St15, St16, St17) and one sample (Sb7) were contaminated with Pseudomonas spp and Salmonella spp, respectively. Among the 21 samples analyzed, 16 had a total aerobic mesophilic flora (TAMF) load ranging from 2 to 4 Log10&nbsp;CFU/mL at 22oC, while the remaining 5 had a TAMF load below 2 Log10&nbsp;CFU/mL. Pathogen identification revealed the presence of Salmonella choleraesuis ssp. arizonae and Pseudomonas aeruginosa. We observed that the contaminated samples originated from the elevated water storage tank in Boukais and from some shallow well samples in Taghit, whereas borehole samples from Nif-Rhaa (Ouakda) and Boukais showed good microbiological quality. Further investigation is needed to identify the source of water contamination. Ensuring water quality is essential for safe aquaculture practices, which contribute to high-quality fish production and national food safety strategies.

Water Quality of Borehole and Shallow Wells Feeding Artificial Fish Ponds in Bechar Province, Southwestern Algeria: Bacteriological and Physicochemical Aspects

<div>Background: Stunting is a process of suppressing growth from unfavourable conditions. The protein supplementation during stunting gives scope to maintain the nutrient reserves of fish and its quality. 
 
Methods: A feeding trial was conducted for eight months to study the effect of three hetero-nitrogenous diets with 25% (control), 30% (T1) and 35% (T2) crude protein (CP) levels on growth and physio-metabolic responses of Chanos chanos fingerlings during stunting. Milk fish fingerlings with a mean body weight of 11.71&plusmn;0.18 g were stocked in earthen ponds @ 20 no/m2 in each replicate (n=3) was fed @ 2% biomass throughout the experiment.&nbsp; 
 
Result:&nbsp;Fish fed with T1 diet showed better specific growth rate (0.64&plusmn;0.01% d-1), weight gain percentage (362.56&plusmn;14.95) and protease activity (7.53&plusmn;0.25 U/mg protein). Whereas, lower activity was observed for the enzyme assay, namely superoxide dismutase (45.41&plusmn;2.50 U/min/mg protein), aspartate aminotransferase (34.01&plusmn;1.88 U/min/mg protein) and alanine aminotransferase (39.64&plusmn;0.64 U/min/mg protein). Hence, it may be concluded that the dietary protein inclusion level of 30% CP showed better growth performance and lower physio-metabolic response in milkfish fingerlings during the stunting.</div>

Effect of Different Dietary Protein Levels on Physio-metabolic Response during Stunting of Milkfish, Chanos chanos (Forsskal, 1775) Reared under Pond Conditions

Background: IMTA is an integrated and eco-friendly farming approach, where organisms from different trophic levels can be cultured in the same system to take advantage of the synergistic interaction between species. 
 
Methods: The experiment was conducted in earthen ponds for four months to investigate the effect of bivalves (M. casta) in halophyte-based IMTA on water quality, growth performance and microbial load. Shrimp and fish were fed with commercial feed containing 35% and 30% crude protein, respectively.&nbsp; 
 
Result: The total ammonia nitrogen, nitrate-nitrogen and nitrite were comparatively low in treatments, T1 (0.13&plusmn;0.012, 0.013&plusmn;0.003 and 0.45&plusmn;0.01, respectively) and T2 (0.15&plusmn;0.005, 0.017&plusmn;0.003 and 0.50&plusmn;0.01, respectively). Similarly, the better average body weight, specific growth rate and feed conversion ratio were found in treatments, T1 (Shrimp: 33.87&plusmn;0.88 g, 6.20&plusmn;0.01% 1.10&plusmn;0.02 respectively, Fish: 94.18&plusmn;0.08 g, 1.59&plusmn;0.001% and 1.60&plusmn;0.006 respectively)&nbsp; and T2 (Shrimp: 32.37&plusmn;0.60 g, 6.16&plusmn;0.02% and 1.15&plusmn;0.02 respectively fish: 92.91&plusmn;0.2 g, 1.59&plusmn;0.009 and 1.63&plusmn;0.08 respectively). Therefore it can be concluded that the use of bivalves helps to create better water quality for the growth and survival of P. vannamei and M. cephalus in halophyte-based integrated multi-trophic aquaculture.

&nbsp;

Effect of Bivalves on Water Quality, Microbial Load and Growth Performance of P. vannamei and M. cephalus in Halophyte-based Integrated Multi-trophic Aquaculture Reared under Pond Conditions

<div>Background: Biofloc technology is a minimal or zero water exchange technology which exerts beneficial effects on water quality, improves feed conversion ratio by recycling microbial protein in the culture of commercially important finfishes and shellfishes. This culture technique also improves the pigmentation in the ornamental fish culture. The presence of pigment producing bacteria and the absorption of the pigments by the ornamental fishes under biofloc technology would pave a long way to boost the production and export market of the high value fishes. Therefore, the present study evaluated the use of bacterial pigments isolated from the biofloc culture in the diets of Swordtail ornamental fish for its colouration and pigment absorption ability. 
 
Methods: A 30 days trial was conducted to evaluate the colour enhancement in swordtail through the supplementation of pigment produced from the bacteria in their diets. Swordtail fishes (1.2 &plusmn; 0.01 g) were stocked in 100 litres tanks (20 nos / tank) in triplicates. Fish fed with normal diet served as control and diet supplemented with pigment (50 mg/kg) isolated from the bacteria Exiguobacterium profundum (T1), Chryseobacterium joostei (T2), Staphylococcus pasteuri (T3), Staphylococcus arlettae (T4) served as treatments. The characteristic features of the pigments isolated from the four different bacteria were checked and showed enhanced antibacterial, total antioxidant activity and the reductive ability. 
 
Result: Significant difference was observed in water quality parameters except temperature between the experimental groups. Growth parameters showed significant difference between control and treatment. Highest carotenoid concentration was found in fishes fed with pigments extracted from Staphylococcus pasteuri compared to other experimental groups. The present study proved the incorporation of bacterial pigments in the diets of Swordtail enhanced the total carotenoid concentration.</div>

<div>Characterisation of Pigment Producing Bacteria Isolated from Bio Floc Ponds and Its Colour Enhancement Effect in Xiphophorus helleri</div>

<div style="text-align:justify">Background:&nbsp;With extensive adoption of mechanised harvest in paddy, the population of blackgram in the rice-blackgram relay cropping system is drastically affected due to the chain traverse by combine harvester. This has emerged as another major abiotic stress in addition to moisture stress at flowering stage of the crop, which resulted in poor yield. 
 
Methods:&nbsp;The studies were conducted during post rainy seasons of 2015-16 to 2017-18. with six treatments viz., T1 - Sowing blackgram by broadcasting 7-10 days prior to manual harvest of paddy, T2 - Sowing blackgram by no till seed drill on the day of harvest of paddy, T3 - Sowing blackgram by broadcasting 4-6 days prior to harvest of paddy by combine harvester, T4 - T1 + Life saving irrigation with mobile sprinkler once at 30-35 DAS, T5 -T2 + Life saving irrigation with mobile sprinkler once at 30-35 DAS, T6 -T3 + Life saving irrigation with mobile sprinkler once at 30-35 DAS. 
&nbsp; 
Result: The results indicated that higher grain yield of 875 kg ha-1 was obtained with blackgram sown 7-10 days prior to manual harvest of paddy plus life saving irrigation on 30-35 DAS with mobile sprinkler using farm pond water, which was 31.6% higher than that of blackgram sowing with no till seed drill. The study also indicated that farm pond dug at an area of 100 m3 would be sufficient to irrigate 1 ha of blackgram through mobile sprinkler once at flowering stage (30-35 DAS by which the net return could be increased by ₹ 61416 ha-1.</div>

<div style="text-align:justify">Crop Establishment Methods and Moisture Mitigation Practices in Rice Fallow Blackgram for Productivity Enhancement in Cauvery Delta Zone of Tamil Nadu</div>

Background: Studies across various regions reveal that declining crop yields and profits are not just caused by environmental damage and stress. Deficiencies in essential nutrients, both major and minor, also play a significant role. This is why integrating organic and inorganic source of nutrients is critical for ensuring food security and self-sufficiency for maize. 
 
Methods: Field experiment was carried out to examine the integrated use of organic and inorganic sources of nutrients on maize growth and yield components at wetland farm, Tamil Nadu Agricultural University, Tamil Nadu during the 2018-19 to 2019-20 with 15 treatment combination under Split plot design with 3 replications. Main plot consist of five treatments of organic sources of nutrients i.e. M1 (Fish pond silt from desi poultry dropping fed pond @ 5 t/ha and vermicompost @ 5 t/ha), M2 (Fish pond silt from duck dropping fed pond @ 5 t/ha and vermicompost @ 5 t/ha), M3 (Fish pond silt from turkey dropping fed pond @ 5 t/ha and vermicompost @ 5 t/ha), M4 (FYM @ 12.5 t/ha), M5 (No manure application) and three sub plot treatments consist of inorganic sources i.e. S1 (100% recommended dose of NPK), S2 (75% recommended dose of NPK) and S3 (No fertilizer application).&nbsp; 
 
Result: The results revealed that the highest grain yield (8293 kg ha-1) and stover yield (11974 ha-1) was obtained with the application of fish pond silt from duck dropping fed pond @ 5 t/ha and vermicompost @ 5 t/ha along with 100% recommended dose of NPK (M2S1) which was 116% and 132% higher to lowest grain yield (3845 kg ha-1) and stover yield (5160 kg ha-1) obtained in control (M5S3).&nbsp;

Integrated Nutrient Management for Enhanced Maize Yield and Sustainability in Tamil Nadu, India

Background: The study has a bifold objectives, firstly to determine the concentration of lead (Pb) in the pond water and bioaccumulation of the lead in the muscles of Danio rerio raised with the same pond water. Secondly, the study seeks to investigate its effect on the anti-oxidant enzyme catalase in Danio rerio, within the vicinity of a historical gold mine region located in the Kolar Gold fields (KGF), Karnataka, India.&nbsp; 
 
Methods: To achieve the objectives, the study employed Thermo Scientific&rsquo;s Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and ICP-AES using Iteva software to evaluate and statistically analyze the distribution of lead in the pond water and and ICP-OES to evaluate the concentration of lead in the muscles sample. Four sample sites (A, B, C and D) were selected based on their proximity to residential area. Pond water samples were analyzed between April and October 2022 following a southwest monsoon rain.&nbsp; 
 
Result: During the study in the pond water, sample site B and D exhibited an exceedingly high Pb concentration during October with 0.98 mg/L against 0.21 and 0.16 mg/L in April 2022 against the maximum permissible value of 0.05 mg/L by WHO 2008 and USEPA 2009, followed by site A and C. The control sample had a normal range of 0.01 mg/L. The concentration of Pb in the muscles on day 30 of October&nbsp; was exceedingly high in the sample site D with 1.9 mg/Kg against 1 mg/Kg on day 30 of April followed by the sample sites B,C and A, which is far above the threshold value as per the regulatory bodies (WHO 2008). The increase in the concentration of the lead decreases the catalase enzyme in the brain region of Danio rerio, the value goes down drastically from 112.3 (&micro;M H2O2 utilized/min/mg protein) to 105.8 in sample site D between day 30 of April and October months, to that of the control value being stable from 151.7 to 150.94 (&micro;M H2O2 utilized/min/mg protein). The outcome of this experiment will facilitate the assessment of pond water contamination levels and the likelihood of contaminants entering the aquatic environment, resulting in the bioaccumulation of heavy metals in the aquatic organisms. The above results clearly indicates the effect of south-west monsoon rain in increasing the levels of lead concentration in the pond water during the month of October to that of April, which indirectly affects the physiology and metabolism of the fishes raised in the contaminated habitat of Kolar Gold Fields.&nbsp;

Bioaccumulation of Pb (Lead) in the Muscles of Danio rerio and its Effect on the Anti-oxidant Enzyme Catalase in the Mining Vicinity of Kolar Gold Fields