Effects of dietary zinc sources and levels on growth performance, tissue zinc retention and antioxidant response of juvenile common carp ( Cyprinus carpio var. Jian) fed diets containing phytic acid

Abstract

Plant protein‐based diets are widely used for common carp (Cyprinus carpio var. Jian). The plant source antagonist, such as phytate, negatively affects the bioavailability of trace minerals, but this aspect was not considered in previous studies on this species. A 10‐week growth trial was conducted to investigate the effects of inorganic Zinc (ZnSO4·7H2O, Zn‐S) and organic Zn (2‐hydroxy‐4‐(methylthio) butanoic Zinc, Zn‐M) on growth performance, Zn retention and antioxidant responses of common carp (initial weight 10.0 ± 0.03 g). Eleven semi‐purified diets containing 7 mg/kg phytic acid were prepared with 0, 5, 20, 35, 50 and 65 mg/kg Zn from Zn‐S and Zn‐M (12.8 mg/kg Zn in basal level), respectively. The results showed that either Zn‐S or Zn‐M inclusion improved growth performance, vertebral Zn deposition and antioxidant responses of fish. The Zn requirement based on WGR, vertebrae Zn and plasma SOD were 47.0, >77.8 and 48.5 mg/kg, and 63.3, 42.2 and 36.8 mg/kg, respectively, with Zn‐S and Zn‐M as Zn sources. The relative bioavailability of Zn‐M was 2.44‐ (vertebrae Zn deposition) and 1.74‐fold (plasma SOD activity) the availability of Zn‐S in the diet of common carp. The lower growth performance and poor bioavailability in vertebrae of Zn‐S group were related to the chelating of zinc with phytic acid.

Impacts of dietary zinc on growth performance, haematological indicators, transaminase activity and tissue trace mineral contents of soft‐shelled turtle ( Pelodiscus sinensis )

“…Aquatic animals fed diets are probably to have evidently higher dietary zinc demand because of the existence of tricalcium phosphate and phytic acid obtained from feed ingredients, which can obstruct zinc in the feed and influence the bioavailability of zinc for aquaculture (Denstadli et al, 2006;Laining et al, 2010;Liang et al, 2020). Compared with previous study, the zinc requirement (60.03-61.27 mg Zn/kg) for soft-shelled turtle was higher than that in previous work (42-46 mg Zn/kg) (Huang et al, 2010).…”

“…Opposite to our result, dietary Zn inclusions had no evident impact on hepatosomatic index (HSI) or viscerosomatic index (VSI) of grass carp (Ctenopharyngodon idella) (Liang et al, 2012), common carp (Cyprinus carpio var. Jian) (Liang et al, 2020) and Jian carp (Cyprinus carpio var. Jian) (Tan et al, 2011).…”

Effects of Different Dietary Zinc (Zn) Sources on Growth Performance, Zn Metabolism, and Intestinal Health of Grass Carp

“…The intestine is the primary organ for absorbing mineral elements derived from diet. It was demonstrated that, compared to the inorganic Zn source (ZnSO 4 ), the dietary organic Zn source (2-hydroxy-4-(methylthio) butanoic Zn) and nano Zn promoted more Zn accumulation in the intestine of fish [ 9 , 10 ]. Zn transport is mainly regulated by ZnTs, ZIPs, and MTF1 [ 2 ].…”

“…Zn sulphate (ZnSO 4 ) is traditionally used in fish feeds, but it suffers from low bioavailability and poor absorption efficiency [ 3 , 8 ]. Studies demonstrated that dietary organic Zn source (2-hydroxy-4-(methylthio) butanoic Zn) or nano-Zn addition promotes growth performance and intestinal Zn accumulation of fish compared to the inorganic Zn source (ZnSO 4 ) [ 9 , 10 ]. Therefore, compared with inorganic Zn sources, organic and nanoform Zn have higher bioavailability, making them effective alternatives to inorganic Zn in aquafeeds [ 10 , 11 ].…”