Figure 1.
Figure 2.
Roles of probiotics in mitigating crowding stress among aquatic animals
| Probiotics/prebiotics – Dosage | Application/Duration | Aquatic animals/stages (weight) | Impacts | References |
|---|---|---|---|---|
| Shewanella putrefaciens Pdp11 – 109 CFU/g | Feed additive | Solea senegalensis | Mitigate crowding stress | (Tapia-Paniagua et al., 2014) |
| 30 days | Juvenile (14.6 g) | Upregulate immune gene transcription | ||
| Modulate gut microbiota | ||||
| Stimulate disease resistance against Vibrio harveyi and V. parahaemolyticus |
Impacts of crowding stress on the growth performance of aquatic animals
| Species (stage) | Stocking density | Environment/Duration | Impact on growth performance | References |
|---|---|---|---|---|
| Sturgeon, Acipenser queldenstaedtii (juvenile) | 8 fish/m3 (low density) and 12 fish/m3 (high density) | Net cage | No significant difference between groups | (Çelikkale et al., 2005) |
| (2 m × 2 m × 2 m) | ||||
| 203 days | ||||
| Nile tilapia, Oreochromis niloticus (juvenile) | 50, 100, 150 and 200 fish/m3 | Net cage | Low-density group demonstrated significantly better outcomes | (Gibtan et al., 2008) |
| 150 days | ||||
| Nile tilapia, Oreochromis niloticus (juvenile) | Stage I: 800, 2000, 2500 and 3000 fish/cage (6 m3) | Cage Stage I: 41 days | Low density showed significantly better results, and fish in uniform size | (Garcia et al., 2013) |
| Stage II: 80, 100 and 120 kg/m3 | Stage II: endpoint when the fish reached 800 g weight | Disease prevalence was higher in the high stocking density group | ||
| Senegalase sole, Solea senegalensis (juvenile) | Initial densities: 7, 17 and 24 kg/m2 | Raceway system | No significant difference between groups | (Andrade et al., 2015) |
| Final densities: 13, 31 and 40 kg/m2 | 60 days | |||
| Chinese sturgeon, Acipenser sinensis (juvenile) | Low density: 4.80 kg/m2 | Recirculating aquaculture system (RAS) 3 months | Low-density group exhibited significantly superior outcomes | (Long et al., 2019) |
| Medium density: 8.99 kg/m2 | ||||
| High density: 12.68 kg/m2 | ||||
| Hybrid sturgeon (Bester ♀ × Beluga ♂ juvenile) | Trial 1: 2 and 4 kg/m2 | Recirculating aquaculture system (RAS) 6 weeks | Low-density group performed significantly better outcomes | (Dediu et al., 2021) |
| Trial 2: 5 and 12 kg/m2 | ||||
| Minor carp, Labeo bata (juvenile) | 50, 75 and 100 fish/m3 | Cage (5 m × 5 m × 3 m) 180 days | Low-density group showed significantly better result | (Karnatak et al., 2021) |
| Hybrid sturgeon (Acipenser baerii ♀ × Acipenser schrenckii ♂ juvenile) | Low density: 100–150 fish/m3 | In flow water pond 60 days | Low density group exhibited significantly better result | (Bi et al., 2023) |
| Medium density: 200–250 fish/m3 | ||||
| High density: 300–350 fish/m3 |
Roles of phytobiotics in mitigating crowding stress among aquatic animals
| Phytobiotics/(dosage) | Application/Duration | Aquatic animals – Stage | Impacts | References |
|---|---|---|---|---|
| Anthraquinone extract from rhubarb Rheum officinale bail (1% and 2%) | Feed additive | Common carp, Cyprinus carpio var. Jian | Improve blood parameters | (Xie et al., 2008) |
| 70 days | Juvenile (5.39 g) | Stimulate disease resistance against Aeromonas hydrophila | ||
| Mitigate crowding stress | ||||
| Stinging nettle, Urtica dioica (1%, 2% and 5% of diet) | Feed additive | Victoria labeo, Labeo victorianus | Improve blood parameters | (Ngugi et al., 2015) |
| 16 weeks | Juvenile (25 g) | Stimulate disease resistance against A. hydrophila | ||
| Female adult (3.4 kg) | ||||
| Male adult (470 g) | ||||
| Saint John’s wort, Hypericum perforatum, lemon balm, Melissa officinalis, rosemary, Rosmarinus officinalis (ratio 3:2:1, 6 g/kg of feed) | Feed additive | Atlantic salmon, Salmo salar | Enhance antioxidant capacity | (Reyes-Cerpa et al., 2018) |
| 40 days | Juvenile (4.83 g) | Mitigate crowding stress | ||
| Rosemary, Rosmarinus officinalis leaf (1–3% of feed) | Feed additive | Common carp, Cyprinus carpio | Improve growth, enhance immune system, increase antioxidant capacity, mitigate crowding stress | (Yousefi et al., 2019) |
| 65 days | Juvenile (12.93 g) | |||
| Oak, Quercus castaneifolia leaf extract (0.5, 1 and 2 g/kg of feed) | Feed additive | Common carp, Cyprinus carpio | Enhance antioxidant and immune system | (Paray et al., 2020) |
| 60 days | Juvenile (20 g) | No significant improvement in growth performance | ||
| Mitigate crowding stress | ||||
| Dehydrated Citrus lemon peel (DLP) (0.5–1.5% of diet) | Feed additive | Rainbow trout, Oncorhynchus mykiss | No significant improvement in growth performance | (Chekani et al., 2021) |
| 45 days | Juvenile (26.8 g) | Enhance antioxidant and immune system | ||
| Improve blood parameters | ||||
| Mitigate crowding stress | ||||
| Pomegranate peel (0.5% of diet) | Feed additive | Common carp, Cyprinus carpio | No adverse impact on the growth performance | (Yousefi et al., 2023 b) |
| 56 days | Juvenile (18.1 g) | Enhance antioxidant and immune system | ||
| Improve blood parameters | ||||
| Mitigate crowding stress |
Roles of feed additives combination in mitigating crowding stress in aquatic animals
| Feed additives – Dosage | Application/Duration | Aquatic animals – stages (weight) | Impacts | References |
|---|---|---|---|---|
| Lactobacillus acidophilus (LAB) + resveratrol (RE) – | Feed additive | Common carp, Cyprinus carpio | Mitigate crowding stress | (Gabr et al., 2023) |
| 1.5 × 107 CFU/g + 300 mg/kg | 60 days | Juvenile (30.16 g) | ||
| Nano selenium + garlic extract – | Feed additive | Grass carp, Ctenopharyngodon idella | Improve growth, increase antioxidant capacity, mitigate crowding stress | (Adineh et al., 2021 a) |
| 1–2 mg + 1–2 g | 60 days | Juvenile (2.1 g) |
Impacts of crowding stress on the immune system and antioxidant capacity of aquatic animals
| Species (stage) | Stocking density | Environment/Duration | Impacts on the immune system and antioxidant capacity | References |
|---|---|---|---|---|
| Rainbow trout, Oncorhynchus mykiss (juvenile) | Low stocking density: 10 kg/m3 | 9 months | Blood cortisol level increases in the high stocking density group | (North et al., 2006) |
| High stocking density: 40 and 80 kg/m3 | Lower lysozyme activity in the high stocking density group | |||
| Rainbow trout (juvenile) | Control group: 15 kg/m3 | Fiber glass tank 1 m (diameter) × 1.2 m (depth) | High stocking density inhibits metabolic and antioxidant enzyme activities | (Aksakal et al., 2011) |
| High stocking density: 20, 25 and 30 kg/m3 | 2 months | High stocking density upregulates heat shock protein (Hsp70) expression | ||
| Senegalase sole, Solea senegalensis (juvenile) | Initial densities: 7, 17 and 24 kg/m2 | Raceway system | No significant difference between groups | (Andrade et al., 2015) |
| Final densities: 13, 31 and 40 kg/m2 | 60 days | |||
| Turbot, Scophthalmus maximus (juvenile) | Low density: 9.3 kg/m2 | Recirculating aquaculture system (RAS) | High stocking density inhibits mucus enzyme activities | (Jia et al., 2016) |
| Medium density: 13.6 kg/m2 | 120 days | High stocking density induces oxidative stress on the skin | ||
| High density: 19.1 kg/m2 | High stocking density downregulated the expression of skin immune-related gene expression | |||
| High stocking density decreases lysozyme activity | ||||
| Grass carp, Ctenopharyngodon idella (juvenile, 98.48 g) | Low density: 0.9 kg/m2 | Tank | High stocking density induces immunosuppression | (Lin et al., 2018) |
| Medium density: – 2.97 kg/m2 | 10 weeks | |||
| High density: 5.9 kg/m2 | ||||
| Chinese sturgeon, Acipenser sinensis (juvenile) | Low density: 4.80 kg/m2 | RAS | High stocking density decreases lysozyme activity | (Long et al., 2019) |
| Medium density: 8.99 kg/m2 | 3 months | |||
| High density: 12.68 kg/m2 | ||||
| Hybrid sturgeon (Acipenser baerii ♀ × Acipenser schrenckii ♂ juvenile) | Low density: 100–150 fish/m3 | In-flow water pond | No significant difference in immune status | (Bi et al., 2023) |
| Medium density: 200–250 fish/m3 | 60 days | High stocking density inhibits antioxidant capacity | ||
| High density: 300–350 fish/m3 | ||||
| Grass carp, Ctenopharyngodon Idella (712.70 g) | Low density: 10 kg/m3 | 120 days | High stocking density induces immunosuppression | (Li et al., 2023) |
| Medium density: 15 kg/m3 | ||||
| High density: 20 kg/m3 |
Roles of synthetic immune stimulants (SIS) in mitigating crowding stress in aquatic animals
| SIS – Dosage | Application/Duration | Aquatic animals/stage | Impacts | References |
|---|---|---|---|---|
| Gallic acid – 150, 300, 450 and 600 mg/kg of feed | Feed additive – 60 days | Common carp, Cyprinus carpio, juvenile | Improve growth, enhance immune system, increase antioxidant capacity, mitigate crowding stress | (Ghafarifarsani et al., 2023) |
| Yeast, Xanthophyllomyces dendrorhous (sexual stage Phaffia rhodozyma) extract – 0.5 g/kg of feed | Feed additive – 40 days | Atlantic salmon, Salmo salar, juvenile (4.83 g) | Enhance antioxidant capacity | (Reyes-Cerpa et al., 2018) |
| Mitigate crowding stress | ||||
| Pennyroyal essential oil – 250 mg/kg of feed | Feed additive – 56 days | Common carp, Cyprinus carpio, juvenile (13 g) | Improve growth, enhance immune system, increase antioxidant capacity, mitigate crowding stress | (Yousefi et al., 2023 a) |
| Chrysin – 100–700 mg/kg of feed | Feed additive – 56 days | Rainbow trout, Oncorhynchus mykiss | Improve growth, enhance immune system, increase antioxidant capacity, mitigate crowding stress | (Yousefi et al., 2023 c) |
| Juvenile (51 g) |