Evaluation of Heavy Metal Content in Feed, Litter, Meat, Meat Products, Liver, and Table Eggs of Chickens

Abstract

We assessed the concentrations of Fe, Cu, Zn, Mn, Se, Co, Cr, Pb, Cd, and Ni in chicken meat and meat products, feed, and litter, as well as laying hens’ eggs, feed and litter to monitor the quality of products on the market and their safety for human consumption as judged by recommended daily allowance (RDA) and tolerable upper levels. Samples were chosen as the most popular poultry products in Saudi Arabia. A total of 45 broiler samples of frozen or fresh meat, liver, burger, or frankfurter were chosen from the same brand. Additionally, 60 table eggs from four commercial brands were collected, and the edible parts of these were used to determine levels of minerals and toxic elements. Furthermore, 30 feed and litter samples were collected from the starter, grower, and layer diets of broilers and laying hens. The results indicated that there were significant levels of most of the trace elements and heavy metals in the different meat sources. Furthermore, the liver contained the highest levels of elements, except for Cr, Co, and Ni. The highest Cr level was detected in the fresh meat, followed by frozen meat. Trace elements (Mn and Co) and heavy metals (Ni and Pb) were not detected in either the frozen or the fresh meat. The chicken burger and the frankfurter exhibited similar trace-element and heavy-metal contents, except for Zn and Mn, as the frankfurter showed higher concentrations than the burger. Differences in most of the trace and toxic elements among the different sources of eggs were not found to be significant, except for Zn. Differences between the broiler meat and table eggs were only substantial for Fe and Zn. Fe was significantly higher in meat than in eggs, and the opposite trend was found for Zn. The liver contained higher heavy metals than the eggs, except for Cr. In addition, the burger had higher concentrations of essential (Cu and Co) and heavy metals (Pb and Ni) than the eggs but had lower levels of Zn and Cr. The frankfurter exhibited significantly higher levels of Fe, Cu, Mn, Co, Pb, and Ni than the eggs but lower levels of Zn and Cr. To summarize, Cd, Pb, As, and Se were not detected in the broiler meat or eggs, indicating no risks from these toxic elements. Conversely, the liver exhibited the highest content of heavy metals, except for Cr, indicating that the intake of Pb and Cd was above the recommended daily allowance (RDA) for adults. The meat products exhibited higher Pb, Cd, and Ni levels than the broiler meat and the table eggs, suggesting that they posed a health threat to humans, and the intake of Pb in the meat products was higher than the RDA. Thus, chicken meat and table eggs, which are primary protein sources, are safe sources of human nutrition, while liver and meat products may present potential health hazards through the food chain.

Effects of Selenium-Enriched Yeast on Performance, Egg Quality, Antioxidant Balance, and Egg Selenium Content in Laying Ducks

“…By comparison with the results of laying performance and egg quality, it was implied that the basal diet with 0.15 mg Se/kg was adequate for productive performance but not for antioxidant balance. In addition, it was acknowledged that Se is key to the maintenance of various physiological and biochemical functions within a small amount, while an excessive dose may lead to harmful effects (41). The Se supplementation at 0.15 and 0.25 mg/kg diet via Se yeast improves the antioxidant balance of the laying ducks in our study, and the average value of Se supplementation level from Se yeast was 0.19 mg/kg for optimum antioxidant balance.…”

“…So far, one of the effective ways to improve Se intake is to consume some functional food, such as Se-enriched egg, meat, and milk products (10,27,62). However, the Se content in ordinary eggs collected from the retail market is under detectable levels (41,63). Many studies have demonstrated that organic Se supplementation of the diets of laying hens translates into greater Se content and Se deposition efficiency in their eggs compared to using inorganic Se (16,17,64,65).…”

Challenges to the Poultry Industry: Current Perspectives and Strategic Future After the COVID-19 Outbreak

“…Se is also part of the deiodinase enzyme essential for the activation of the thyroid hormone ( 97 , 101 , 102 ). The main functions of selenoproteins are control of redox of biochemical function, antioxidant balance systems, thyroid hormone anabolism and catabolism ( 106 ), anticancer protection ( 108 ), and immune function booster ( 117 , 118 ). Hence, Se-enhanced animal products can improve animal immunity, prevent diseases caused by Se deficiency, and enrich general health ( 97 , 101 , 102 ).…”

“…Hence, Se-enhanced animal products can improve animal immunity, prevent diseases caused by Se deficiency, and enrich general health ( 97 , 101 , 102 ). Se fortification can enhance the antioxidant balance of animals and improve product quality and animal performance ( 119 – 121 ), but excess Se may hurt the environment ( 108 , 117 ).…”

Beneficial effects of substituting soybean meal for white lupin (Lupinus albus, cv. Zulika) meal on the biochemical blood parameters of laying hens

“…Birds receiving diets containing reduced levels of trace elements had diminished excretions of Mn and Zn throughout the entire period (p < .01) and droppings of such broilers, fed with this feed mixtures, were not loading the environment too much with trace elements residues. Also Korish and Attia (2020) assessed the concentrations of Fe, Cu, Zn, Mn, Se, Co, Cr, Pb, Cd, and Ni in chicken meat and meat products, feed, and litter, as well as laying hens' eggs, feed and litter to monitor the quality of products on the market and their safety for human consumption and their results indicated that there were significant levels of most of the trace elements and heavy metals in the different meat sources.…”