Effects of Zinc Lactate Supplementation on Growth Performance, Intestinal Morphology, Serum Parameters, and Hepatic Metallothionein of Chinese Yellow-Feathered Broilers

In poultry, organic zinc compounds have higher bioavailability than inorganic zinc sources. However, as an organic zinc source, the application of zinc lactate (ZL) on Chinese yellow-feathered broilers has been rarely reported. Hence, the present study aimed to investigate the effects of ZL supplementation on growth performance, small intestinal morphology, serum biochemical parameters, immune organ index, as well as hepatic metallothionein of Chinese yellow-feathered broilers. A total of 2100 broilers (19 days old) were randomly assigned to 5 treatment groups, including the control (fed basal diet), ZL40 (basal diet plus 40 mg/kg ZL), ZL60 (basal diet plus 60 mg/kg ZL), ZL80 (basal diet plus 80 mg/kg ZL), and ZS80 (basal diet plus 80 mg/kg ZS. Each treatment group had 6 replicates with 70 chickens per replicate. Compared to the control group, the ZL40 and the ZS80 groups had a lower feed to gain ratio (P < 0.05), ZL40 group had higher duodenum and ileum villus heights (P < 0.05), and ZS80 and ZL80 groups had a lower ratio of villus height to crypt depth in the jejunum (P < 0.01). In addition, the ZL60 group had a higher concentration of total protein (P < 0.05) and activity of glutathione peroxidase (GSH-Px) (P < 0.01) compared with the ZS80 and the control groups. Interestingly, the ZL40, ZL60, and ZL80 groups all had higher levels of hepatic metallothionein than the other groups (P < 0.01). In conclusion, zinc lactate had a higher bioavailability and could be used as an alternative to zinc sulfate.

Antioxidant potential of bulk and nanoparticles of naringenin against cadmium-induced oxidative stress in Nile tilapia, Oreochromis niloticus

The study assessed the attenuating effect of citrus flavonone, naringenin, and its nanoformulation against cadmium (Cd) toxicity in Nile tilapia (Oreochromis niloticus). Nanoparticles of naringenin (NNn) were synthesized; size 165.1 nm (PDI 0.396) in variable shapes; cluster widespread, spherical accumulated, and tubular bacillary. Parallel, mature male Nile tilapia (n = 120 fish) were used for the exposure study. Group I was negative control. The groups II, III, and IV were exposed to 5 ppm of cadmium chloride monohydrate (CdCl2·H2O) for 21 days. Group III was treated with bulk naringenin (BNn) (3 ppm) and group IV was treated with NNn (3 ppm). Group V was exposed only to NNn (3 ppm). Cd-induced oxidative stress was evident from a significant increase in the hepatic malondialdehyde (MDA) levels and modulation of antioxidant enzymes in the liver and kidney. A significant increase in the hepatic metallothionein and HSP70 levels in the gills was observed. Treatment with both BNn and NNn significantly (p ≤ 0.05) reversed the Cd-induced alterations. However, the protective effect of nano naringenin was more profound on the bioaccumulation of Cd in liver and levels of HSP70 in the gills. These key findings could add to the commercial exploitation of naringenin and its nanosized form as a dietary therapeutic molecule.

Dietary Zinc Supplementation to Prevent Chronic Copper Poisoning in Sheep

The aim of this study was to evaluate whether zinc (Zn) supplementation protects against hepatic copper (Cu) accumulation in copper-loaded sheep. Forty cross-bred lambs were assigned to five experimental groups. These included the control group (C) and four treatment groups that received Cu and/or Zn supplementation (dry matter (DM) basis) over 14 weeks, as follows: Cu (450 mg Cu/kg); Zn-35 (450 mg Cu + 35 mg Zn/kg); Zn-150 (450 mg Cu + 150 mg Zn/kg); and Zn-300 (450 mg Cu + 300 mg Zn/kg). Blood, liver, and bile samples were obtained for mineral determination by inductively coupled plasma optical emission spectrometry (ICP–OES). The hepatic metallothionein (MT) concentrations were also determined. At the end of the experiment, hepatic Cu concentrations were higher in all Cu-supplemented groups than in C. Hepatic Cu accumulation was lower in the groups receiving the Zn supplementation than in the Cu group, although the difference was only statistically significant (66%) in the Zn-300 group. The MT concentrations tended to be higher (almost two-fold) in the Zn groups (but were not dose related) than in the C and Cu groups, and they were related to hepatic Zn concentrations. Zn supplementation at 300 mg/kg DM is useful for preventing excessive hepatic Cu accumulation in sheep exposed to high dietary concentrations of Cu.

Human Metallothionein Enhanced Tolerance and Biosorption of Cadmium when Expressed in Saccharomyces cerevisiae

The recombinant Saccharomyces cerevisiae expressing human hepatic metallothionein (MT) was constructed for biosorption of cadmium (II). The gene sequence of mt was modified for codon preference of S. cerevisiae and synthesized using chemical method. The maximal biosorption capability of cadmium compounds Cd2+ of the recombinant increased more than 25.8% compared with the control. For MT-expressed recombinant strains, a rapid adsorption occurred within the first 30 min with a significant level of Cd2+ (55.75mg/g). For comparison, S. cerevisiae cells reach its maximal Cd2+ adsorption capacity (45.02 mg/g) until 2h. Furthermore, recombinant strain were able to withstand the toxicity of Cd2+ and grow. The results indicated that recombinant should be useful in enhancement the tolerance and biosorption of cadmium in practice.