Dietary zinc addition influenced zinc and lipid deposition in the fore- and mid-intestine of juvenile yellow catfishPelteobagrus fulvidraco

Abstract

The present study explored the mechanisms of dietary Zn influencing Zn and lipid deposition in the fore- and mid- intestine in yellow catfish Pelteobagrus fulvidraco, and investigated whether the mechanism was intestinal-region dependent. For this purpose, yellow catfish were fed three diets containing Zn levels of 8·83, 19·20 and 146·65 mg Zn/kg, respectively. Growth performance, intestinal TAG and Zn contents as well as activities and mRNA expression of enzymes and genes involved in Zn transport and lipid metabolism in the fore- and mid-intestine were analysed. Dietary Zn increased Zn accumulation as well as activities of Cu-, Zn-superoxide dismutase and ATPase in the fore- and mid-intestine. In the fore-intestine, dietary Zn up-regulated mRNA levels of ZnT1, ZnT5, ZnT7, metallothionein (MT) and metal response element-binding transcription factor-1 (MTF-1), but down-regulated mRNA levels of ZIP4 and ZIP5. In the mid-intestine, dietary Zn up-regulated mRNA levels of ZnT1, ZnT5, ZnT7, MT and MTF-1, but down-regulated mRNA levels of ZIP4 and ZIP5. Dietary Zn reduced TAG content, down-regulated activities of 6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and fatty acid synthase (FAS) activities, and reduced mRNA levels of 6PGD, G6PD, FAS, PPARγ and sterol-regulator element-binding protein (SREBP-1), but up-regulated mRNA levels of carnitine palmitoyltransferase IA, hormone-sensitive lipase (HSLa), adipose TAG lipase (ATGL) and PPARα in the fore-intestine. In the mid-intestine, dietary Zn reduced TAG content, activities of G6PD, ME, isocitrate dehydrogenase and FAS, down-regulated mRNA levels of 6PGD, G6PD, FAS, acetyl-CoA carboxylase a, PPARγ and SREBP-1, but up-regulated mRNA expression of HSLa, ATGL and PPARγ. The reduction in TAG content following Zn addition was attributable to reduced lipogenesis and increased lipolysis, and similar regulatory mechanisms were observed between the fore- and mid-intestine.

Nano-Zn Increased Zn Accumulation and Triglyceride Content by Up-Regulating Lipogenesis in Freshwater Teleost, Yellow Catfish Pelteobagrus fulvidraco

“…The in vitro study found that the protein level of MTF1 and the mRNA levels of Zn transport genes (znt5, znt7, mt, and mtf1) were higher in the nano-Zn group than in the ZnSO 4 group. These data indicated that these key genes and proteins mediated the Zn uptake, transport, and metabolism, in agreement with other studies [6,19]. Studies suggested that nano-Zn can be dissolved in the digestive tract and accordingly release Zn 2+ [20].…”

Dietary addition of zinc-methionine influenced eggshell quality by affecting calcium deposition in eggshell formation of laying hens

“…After filtration (Whatman filter), the volume was increased to 50 ml with demineralised water prior to analysis, according to the method of Gheisari et al (27) ; egg white or yolk was defrosted, mixed and 0•5 g was placed in a plastic high-pressure tube for digestion (7 ml of nitric acid and 2 ml of hydrochloric acid) using an organic program. After cooling, the samples were transferred to 100 ml flasks and brought to 100 ml volume with deionised water for the homogenisation (28) ; Zn contents in serum, ovary, magnum and ESG were measured according to the method of Chen et al (29) . Flame atomic absorption spectrophotometry was used in the determination.…”

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

“…Overestimates of bioavailability (100%) and the poor growth performance of fish fed semi‐purified diets might have underestimated micronutrient requirements of fish (Paripatananont & Lovell, ; Wang et al, ). Inhibited feed intake and growth seems to be more apparent for carnivorous fish species than omnivorous or herbivorous fish (Chen et al, ; Wang et al, ). Juvenile yellow catfish exhibited poor growth performance (only 1.11–1.25 g weight gain) when fed a casein‐based basal diet even when formulated with adequate (19.2 mg/kg) to excess levels (146.65 mg/kg) of Zn for 8 weeks (Chen et al, ).…”

“…Inhibited feed intake and growth seems to be more apparent for carnivorous fish species than omnivorous or herbivorous fish (Chen et al, ; Wang et al, ). Juvenile yellow catfish exhibited poor growth performance (only 1.11–1.25 g weight gain) when fed a casein‐based basal diet even when formulated with adequate (19.2 mg/kg) to excess levels (146.65 mg/kg) of Zn for 8 weeks (Chen et al, ). In the present study, a semi‐purified basal diet with 130 g/kg krill meal as palatability enhancer and 7 g/kg sodium phytate as an original antinutritional factor, which usually chelates with and decreases the digestibility of minerals in feedstuff mixtures, was used (Konietzny & Greiner, ).…”