Efficacy of sodium bicarbonate (Baking soda) and clove powder (Syzygium aromaticum) as anaesthetic agents for Nile tilapia (Oreochromis niloticus, linnaeus 1758) juveniles

Anaesthetics in aquaculture serve as a stress avoidance mechanism, mitigating stress-related impacts during fish handling and transportation. This study assessed the efficacy of sodium bicarbonate and clove stem powder as anaesthetic agents for Nile Tilapia juveniles. Four hundred and twenty uniform O. niloticus juveniles (5 ± 0.5 g, 74 ± 5 mm) were exposed to varying concentrations of sodium bicarbonate (10, 15, 20, 25, 30, 35, 40 g/L) and clove stem powder (0, 1, 3, 5, 7, 10, 15 g/L) in 20 L transparent plastic tanks. The results showed an inverse relationship between anaesthetic concentration and induction time, a direct relationship with recovery time, and an inverse correlation between induction and recovery times for both agents (P < 0.001). The Appropriate concentrations were determined as 25 g/L for sodium bicarbonate and 10 g/L for clove stem powder. At these levels, induction and recovery times met ideal criteria (3-5 min induction, 5-10 min recovery), with fish exhibiting normal behavior and 100% survival after a week of monitoring

Assessment of trace elements (Cu, Fe, and Zn) in Limnothrissa miodon from Lake Kariba, Zambia: implications for ecological and human health

This study examined Copper (Cu), Iron (Fe), and Zinc (Zn) levels in Limnothrissa miodon fish from Lake Kariba in Zambia and their potential impact on human health. Two-gram samples from each stratum underwent a 12-hour digestion, and concentrations were determined using Microwave Plasma Atomic Emission Spectrometer. Results indicated that Cu, Fe, and Zn concentrations fell within Food and Agricultural Organization and World Health Organization safety limits. Estimated Daily Intake (EDI) and Hazard Quotient (THQ) values for males and females remained under recommended thresholds, suggesting minimal health risks from consumption. Element concentrations followed the order Fe > Zn > Cu, all below Recommended Daily Allowances (RDAs). THQ values, with Zn posing the highest potential risk followed by Fe and Cu, were under one. Overall, the Hazard Index (HI) was 0.02, signifying a low non-carcinogenic risk from fish consumption. Despite safety, ongoing monitoring of heavy metal accumulation in the ecosystem is advisable for long-term safety. In conclusion, trace element levels in Limnothrissa miodon from Lake Kariba are safe for human consumption with low associated health risks. Nonetheless, continued monitoring of heavy metal levels is vital

Nutritional requirements and effect of culture conditions on the performance of the African catfish (Clarias gariepinus): a review

AbstractAquaculture is crucial for global food and nutrition security due to the inability of wild harvests to meet increasing demand. Africa’s contribution to aquaculture is generally low, despite its potential for economic development, food security, and reduced unemployment. The study focuses on the African catfish (Clarias gariepinus) a freshwater fish species that is widely farmed for food in Africa and other parts of the world. Proper nutrition is essential for the growth and development of the fish, and understanding their nutritional requirements is critical for producing healthy and high-quality fish. This review article provides an overview of the knowledge on the nutritional requirement of the African catfish, including protein, lipids, carbohydrates, vitamins, minerals, and amino acids. The recommended protein content for juvenile fish is between 40 and 50% and for adult fish is between 30 and 40%. Based on the reviewed studies, the recommended amount of methionine in C. gariepinus diets ranges from 18.7 to 29.7 g/kg of protein while the lysine requirement ranges from 44.9 to 62.2 g/kg protein). The recommended lipid content in the diet is between 5–15% for juvenile fish and 5–10% for adult fish. The African catfish requires a low-carbohydrate diet, with recommended carbohydrate content between 26 and 32%. They require a variety of vitamins, including vitamin A, vitamin D, vitamin E, and vitamin C, as well as minerals, such as calcium, phosphorus, and potassium. Clarias gariepinus also require a variety of essential and non-essential amino acids. Besides the nutritional requirements, culture conditions also have a significant effect on the feed performance. The recommended conditions include temperature ranging from 28 to 32 °C, Light intensity of 150 Lx, 12D:12L photoperiod, and stocking density in earthen of 7 fish m−3. Overall, understanding the nutritional requirements of C. gariepinus is crucial for the successful fish farming and sustainable aquaculture. Information in this review will be built to further guide the development of feeds for C. gariepinus

Application of anaesthetics in fish hatcheries to promote broodstock and fish seed welfare in Zambia

AbstractThis study investigated the application of anaesthetics in 23 private and government-owned hatcheries in 10 provinces of Zambia. The study employed both qualitative and quantitative research designs and used a structured questionnaire to collect data from the respondents. The results showed that most hatcheries (65%) were not using anaesthetics in handling fish and all (100%) that were using anaesthetics (35%) used clove powder as the only type. Most respondents (61%) were not sure or did not have information about the availability of the anaesthetic substances in their localities while only 26% reported wider availability but 13% had a divergent claim. The mortality rate for fingerlings in hatcheries that applied anaesthetics ranged between 15–30% with consistently high demand while those that did not use anaesthetics reported mortality rates of more than 50% and had low demand. The majority of the respondents (53%) had received training up to certificate level, followed by those who had attained up to a diploma qualification (27%) while those that attained up to a degree (13%) and general skills (7%) levels were in the minority. Furthermore, most respondents (35%) did not know the importance of fish anaesthetics. We conclude that the use of fish anaesthetics in Zambian hatcheries is very low and could partly be the cause of high fingerling mortalities, and there is an urgent need to address the situation