Tilapia obesity leads to reduced disease resistance; how to prevent and treat it

Tilapia farming

    [Pathogen]: When tilapia are fed diets low in protein and high in fat and carbohydrates and lacking vitamins over the long term, fat metabolism is impaired, large amounts of fat accumulate, the fish become obese, and disease resistance decreases.

    [Symptoms and diagnosis]: In tilapia suffering from obesity, fat cells proliferate throughout the body and fat infiltrates the tissues; in particular, the adipose tissue in the abdominal cavity and around the organs increases markedly. In diseased fish, the abdominal adipose tissue accounts for 3%-5% of body weight, the liver is pale yellow, the liver tissue shows severe fatty degeneration, and the liver cells atrophy. If an entire piece of liver tissue is cut out and placed in water, it will float on the surface, whereas a normal liver will immediately sink to the bottom.

    [Epidemiology and harm]: In intensive tilapia farming, stocking density is high. If the diet is nutritionally inappropriate, this disease readily occurs. The disease mainly harms sexually mature tilapia. Diseased fish have low disease resistance and are susceptible to infections such as Escherichia coli and Aeromonas. Obesity creates conditions for infection by opportunistic pathogens. Bacterial infections secondary to obesity cause even more serious harm to tilapia.

    [Prevention and treatment]: (1) Improve the feed formula to meet the normal growth needs of tilapia as much as possible. Appropriately add vitamin B, vitamin C, and vitamin E to the feed. Natural feed can also be increased. (2) Obesity mainly harms sexually mature tilapia, so mature tilapia should be harvested and marketed in a timely manner, which can reduce losses and alleviate the condition. (3) Strengthen feeding management, keep the water quality clean and fresh, and administer antibiotics regularly.