Dietary exposure to melamine and cyanuric acid induced growth reduction, oxidative stress and pathological changes of hepatopancreas in Pacific white shrimp

Abstract

This study examined the effects of dietary melamine (MEL) and cyanuric acid (CYA) singly and in combination on growth, nutrient utilization, immunological responses, oxidative stress, and histological changes in Pacific white shrimp. Seven experimental isonitrogenous (35%) and isolipidic (8%) diets were formulated, namely diet 1 (a control diet without MEL and CYA); diets 2-5 (with MEL and CYA at 2.5 ? 2.5, 5 ? 5, 7.5 ? 7.5 and 10 ? 10 g kg -1 diet); diet 6 (with only MEL at 10 g kg -1 diet) and diet 7 (with CYA alone at 10 g kg -1 diet). The shrimp with initial body weight 2.37 ± 0.02 g were fed with these diets for 10 weeks. The results indicate that all the diets with MEL and CYA singly or in combination had adverse effects on growth and nutrient utilization relative to the control diet (p \ 0.05). Total protease and trypsin activities were significantly lowered by all diets containing MEL (p \ 0.05). Haemolymph parameters, including total hemocyte count, phenoloxidase (PO) activity, respiratory burst, and lysozyme activity, were significantly decreased (p \ 0.05) in shrimp receiving MEL alone (10 g kg -1 diet) and at high combination dosages (10 ? 10 g kg -1 diet). Moreover, MEL and CYA induced oxidative stress, damaged hepatopancreas, decreased antioxidant responses, increased lipid peroxidation, and caused abnormality of hepatocytes.

Adulteration of aquafeed with melamine and melamine‐formaldehyde chemicals; Ex situ study of impact on haematology and antioxidant systems in Clarias gariepinus

“…In the present study, dietary uptake of MEL and MEF caused a significant reduction in body biomass of the exposed groups and may suggest underutilization of MEL/MEF contaminated diets. The findings of the present study validate the reports of previous studies, which emphasized the toxicity of MEL, as it caused significant reduction in growth of white shrimp (Nuntapong et al, 2019), red tilapia (Phromkunthong et al, 2013) and Asian sea bass (Phromkunthong et al, 2015). On the contrary, Samranrat et al (2011) reported no significant decrease in the growth of black Tiger shrimp treated with MEL doses ranging from 0.005 to 5.0 g Kg −1 ).…”

“…The liver is an essential organ for the detoxification of chemicals and is sensitive to stress responses (Yu et al, 2016). The result of this study consolidates the finding of Nuntapong et al (2019), who noted significant decreases in SOD, GPx and CAT activities in hepatopancreas of pacific white shrimp treated with 10 g Kg −1 MEL contaminated diet. Phromkunthong et al (2015) emphasized the toxicity of MEL following its inhibitory effect on GPx and CAT activities in the liver and kidney of Asian sea bass.…”

“…It is also important to state that MEL and MEF incorporated into fish diets do not contribute any nutrient. The selected dose (3.0 g Kg −1 ) reflects a chronic scenario of these chemicals, as up to 5–30 g Kg −1 have been reported to induce toxic effects in tilapia fish ( Oreochromis niloticus ) (Phromkunthong et al, 2013) and Pacific white shrimp (Nuntapong et al, 2019). The formulated diets were mechanically mixed and pelletized and air dried at 25°C for 24 h. The processed diets were stored at 4°C in a refrigerator prior to use.…”

“…MEL and co‐polymer (melamine formaldehyde) are used in the production of thermoplastic materials like coating materials, fire retardants, dish wares and resins (Roviello et al, 2015). However, it has also been reported that these chemicals are rich in nitrogen and usually referred to as fake protein, which explains why they are illegally used as an adulterant in animal feed in many countries (Nuntapong et al, 2019; USFDA, 2007). MEL has been detected in animal feed, infant milk and different animal tissues (Phromkunthong et al, 2015; World Health Organization, 2009).…”

“…The toxic effects of MEL have been reported in various fish species such as suppression of growth, immune system and antioxidant system (Nuntapong et al, 2019; Phromkunthong et al, 2015). Other adverse effects of MEL/MEF include hepatotoxicity, nephrotoxicity and behavioural aberrations (Iheanacho, Igberi, Amadi‐eke et al, 2020; Mahardika et al, 2017; Pacini et al, 2013; Pirarat et al, 2012; Xue et al, 2011).…”