Application of phytochemicals as growth‐promoters and endocrine modulators in fish culture

Abstract

There is a constant need to increase productivity in aquaculture, particularly to improve growth rate, feed utilization as well as stress resistance of fish. Because of consumer concerns and strict regulations in many countries, the use of synthetic chemicals, hormones and antibiotics is becoming unviable and natural compounds are more acceptable to the public. A wide variety of chemical compounds are found in plants, and many of them have been shown to have beneficial effects on appetite, growth and the immune status of fish acting through different mechanisms. Phytochemicals contained in herbs may enhance the innate immune system, possess antimicrobial capabilities, and are redox active molecules with antioxidant characteristics that may help to improve the general physiological condition of fish. Many studies have discussed the values of phytochemicals as feed additives. Another paramount concern related to phytochemicals is their endocrine modulator effect that can be applied both in aquaculture targeting the production of table fish and the growing sector of ornamental fish production. Different mechanisms such as the effects at the steroid receptor level, effects on steroid synthesis, distribution and excretion, actions on the hypothalamuspituitary-gonad axis, as well as indirect mechanisms including thyroid and growth hormone disruption have been postulated for the reproductive endocrine disruption in fish populations by phytochemicals. This paper reviews the results of a great number of studies focusing on phytochemicals such as essential oils, saponins, flavonoids and phytosterols discussing their effects on productive traits and the putative mechanism of action.

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“…In general, compounds such as flavonoids have been associated with the antioxidant activity of the plant extract. Other phytochemicals found to be present in the methanol extract of B. alba leaves are reported to have many beneficial health effects as well (Chakraborty and Hancz, 2011;Chakraborty et al, 2014). However, quantitative estimation of flavonoids and phenols needs to be done with the extract to determine the correlation between the available phytochemicals and the antiradical activity of the plant.…”

“…Traditional use of antibiotics and other chemotherapeutics in fish culture has been criticized because of the potential development of antibiotic-resistant bacteria, environmental pollution and accumulation of residues in fish. Since the European Union ratified a ban in 2006 for the use of all sub-therapeutic antibiotics intensified efforts to identify and develop safe dietary supplements and additives that enhance the life activity, health and immune system of farm fish (Chakraborty and Hancz, 2011;Chakraborty et al, 2014).…”

“…Besides, attempts have been made to use the therapeutic potential of this isoflavone for growth induction and health promotion in fish (Chakraborty and Hancz, 2011;Chakraborty et al, 2014). Malabar spinach, Basella alba (family Basellaceae) is a fast growing vegetable, native to tropical Asia, probably originating from India or Indonesia and extremely heat tolerant (Bamidele et al, 2010).…”

“…The Nile tilapia, Oreochromis niloticus (Linnaeus) is a well-studied, fast-growing and widely cultured fish species throughout the world. Plant-derived immunostimulants could improve the immune status of fish by raising the number of phagocytes and enhancing lysozyme and complement activities and the immunoglobulin level leading to increase in fish production (Chakraborty and Hancz, 2011;Chakraborty et al, 2014). Considering these aspects, the present study was focused to evaluate the efficacy of genistein and methanol extract of B. alba for promotion of general health and growth in Nile tilapia.…”

The effects of dietary Eleutherine bulbosa on the growth, leukocyte profile, and digestive enzyme activity of the striped catfish Pangasianodon hypophthalmus

“…Previous research has been carried out to evaluate the feasibility of using herbal plants in aquaculture (Chakrabarti 2005;Citarasu 2010;Thanikachalam et al N U S A N T A R A B I O S C I E N C E 10 (1): 47-52, February 201847-52, February 48 2010Chakraborty et al 2014;Van Hai 2015). Various physiological tools have been used to evaluate effects of feedstuffs on the growth performance and health of fish.…”