Journal of Fisheries

Effect of L-proline supplementation on long-term cryopreservation of Piaractus brachypomus sperm: post-thaw motility, viability, and morphological assessment of sperm

2026-07-17T12:35:54+00:00

Sperm cryopreservation is widely used in aquaculture for long-term preservation of genetic resources and broodstock management; however, prolonged storage can adversely affect sperm quality due to structural damage and ionic imbalance. This study evaluated the influence of L-proline supplementation, with and without dimethylsulfoxide (DMSO), on the cryopreservation efficiency of Piaractus brachypomus sperm. Milt from hormonally induced males was cryopreserved in Modified Cortland Medium (MCM) supplemented with 2, 5, 10, and 30 mM L-proline, either in the absence of DMSO or in combination with 10% DMSO, and maintained under liquid nitrogen for 90 days. Sperm quality after thawing was evaluated at 15-day intervals. Significant differences were observed in sperm motility and viability among treatments. Among the MCM supplemented with L-proline treatments, 10 mM L-proline maintained the highest post-thaw sperm motility (58.05–53.40%) and viability (62.50%), whereas the MCM without cryoprotectant showed the lowest values. Among the MCM containing 10% DMSO treatments, 10% DMSO and 10% DMSO + 2 mM L-proline maintained comparatively higher post-thaw sperm motility (54.36–51.04% and 56.44–49.75%, respectively), whereas other groups exhibited higher post-thaw sperm viability (>52%) than the other DMSO-based treatments. Although a progressive decline in sperm quality was observed over the 90-day storage period, L-proline-supplemented groups maintained superior functional performance. Morphological assessment showed better preservation of sperm head integrity and fewer structural abnormalities in the 10 mM L-proline treatment compared to other cryopreserved treatments. The findings indicate that supplementation with 10 mM L-proline enhances sperm membrane stability and overall cellular function during cryostorage.

Effect of dietary L-ascorbic acid and L-leucine and their combination on growth performance, survival and feed utilisation in Labeo catla fingerlings

2026-07-17T08:27:21+00:00

The present investigation was carried out for a period of 75 days to evaluate the effects of dietary supplementation of L-ascorbic acid and L-leucine on growth performance and feed utilisation in Labeo catla fingerlings. A total of nine experimental diets were formulated with different levels of L-leucine and L-ascorbic acid, including a control (T₀) without supplementation. The treatments consisted of T₁ (10 g L-leucine), T₂ (15 g L-leucine), T₃ (0.3 g L-ascorbic acid), T₄ (0.4 g L-ascorbic acid), T₅ (0.3 g L-ascorbic acid + 10 g L-leucine), T₆ (0.4 g L-ascorbic acid + 10 g L-leucine), T₇ (0.3 g L-ascorbic acid + 15 g L-leucine) and T₈ (0.4 g L ascorbic acid + 15 g L-leucine). The results indicated significant improvement in the highest final weight (3.86±0.38 g), specific growth rate (1.95±0.10% day^–1), and protein efficiency ratio (1.74±0.08), along with the lowest feed conversion ratio (1.93±0.09) in T₆. The combination of 0.4 g L-ascorbic acid and 10 g L-leucine (T₆) was found to be the most effective and is recommended for enhancing growth and feed utilisation in L. catla fingerlings.

Immunomodulatory effects of indigenous herbal feed additives on innate immunity of common carp (Cyprinus carpio) challenged with Aeromonas hydrophila

2026-07-17T08:27:31+00:00

The increasing incidence of bacterial diseases in aquaculture necessitates the development of sustainable immunostimulatory strategies as alternatives to antibiotics. The present study evaluated the immunomodulatory and growth-promoting effects of indigenous herbal feed additives on common carp (Cyprinus carpio) challenged with Aeromonas hydrophila. Fish were fed diets supplemented with neem (Azadirachta indica), tulsi (Ocimum sanctum), and their combination for 90 days under controlled conditions, followed by bacterial challenge. Hematological parameters, including hemoglobin (Hb), red blood cell (RBC) count, total leukocyte count (TLC), and packed cell volume (PCV), along with growth indices such as specific growth rate (SGR), weight gain, and feed conversion ratio (FCR), were evaluated. Results showed a significant improvement in hematological and immune parameters in all treated groups compared to control, with the combined supplementation (neem + tulsi) exhibiting the most pronounced effects. The highest Hb, RBC, TLC, and PCV values were observed in the combination group, indicating improved oxygen transport capacity and immune competence. Growth performance was also significantly improved, as indicated by higher SGR and weight gain and lower FCR. Following bacterial challenge, treated groups exhibited increased resistance and survival, confirming the protective role of herbal supplementation. The findings demonstrate that dietary inclusion of indigenous herbal additives, particularly in combination, effectively enhances innate immunity, hematological health, and growth performance in common carp (Cyprinus carpio). This study highlights the potential of phytogenic feed additives as eco-friendly and sustainable alternatives for disease management in aquaculture systems.

Formulation and characterization of Halymenia dilatata-based nori alternative through nutritional, sensory, structural, textural, and functional analyses

2026-07-17T08:27:41+00:00

The increasing demand for seaweed-based foods has created interest in developing sustainable alternatives to conventional Porphyra-based nori using tropical seaweed resources. This study developed a nori-like product from Halymenia dilatata and evaluated the effects of glycerin concentration and drying conditions on its nutritional, physicochemical, structural, and sensory properties. Four formulations were prepared using a constant seaweed-to-water ratio (1:10, w/v) with varying glycerin concentrations. The formulation containing 2.5% glycerin and dried at 55°C for 2 h produced sheets with the best pliability, uniformity, and handling characteristics. The optimized product contained low moisture (7.84%), moderate protein (11.62%), high dietary fibre (31.54%), and a mineral-rich ash content (14.87%), with appreciable levels of iron and zinc and a balanced sodium-to-potassium ratio. Sensory evaluation indicated good consumer acceptance for appearance, flavour, texture, and overall acceptability. Structural analyses confirmed the formation of a cohesive polysaccharide network, while biochemical and microbiological analyses demonstrated favourable quality, oxidative stability, and microbial safety. These findings demonstrated that H. dilatata could be successfully developed into a nutritious, safe, and acceptable nori-like product with physicochemical characteristics comparable to those of conventional nori, highlighting its potential as a sustainable tropical alternative for value-added seaweed-based food products.

Age and growth of Oreochromis niloticus in the Samandéni Reservoir, Burkina Faso: a scale-based study

2026-07-17T08:27:52+00:00

Oreochromis niloticus is a key species supporting inland fisheries in tropical African reservoirs, including the recently impounded Samandéni Reservoir in Burkina Faso. However, age-based information required for reliable stock assessment remains limited for this reservoir. This study estimated age structure, growth parameters, and population characteristics of O. niloticus using scale readings from 318 specimens collected monthly between October 2021 and September 2022 at three sampling sites: Badoville (n = 114), Sadina (n = 100), and Dioufoulma (n = 104). Monthly sample sizes were relatively uniform, ranging from 25 to 28 individuals, ensuring consistent temporal coverage throughout the study period. Scale annuli were examined and validated using marginal increment analysis. The population exhibited a unimodal length-frequency distribution ranging from 10.0 to 32.0 cm (mean±SD: 20.38±0.17 cm). The sex ratio was significantly male-biased (2.06:1, χ² = 38.04, p < 0.001). Length–weight relationships indicated isometric growth for the pooled population (b = 2.96), negative allometry in males (b = 2.92), and isometric growth in females (b = 3.09). Marginal increment analysis confirmed annual annulus formation, with minimum values occurring in February during the dry season. The von Bertalanffy growth model showed rapid juvenile growth followed by a progressive decline after maturation. Age classes ranged from 0+ to VI+, with dominance of intermediate age groups (II+ to IV+), suggesting continuous recruitment and moderate exploitation pressure. These results provide the first validated scale-based age and growth parameters for O. niloticus in the Samandéni Reservoir and contribute essential baseline information for sustainable fisheries management.